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IELLING HOME COMPUTER MAGAZINE 



Vol. 3 No. 4 



45uggy road test 
step for 




Snaking on 
me Vic 7 

-81 file system 

Plus plenty of games and 
features for the BBC, Ape, 
Atari and Dragon 



n6kor :Sk} 
£K SPECTRUM 



SFEU 



Ike WoM,'i. Qnetded A- 



From our team of outstar 
come games crammer 1- 




rpgram experts 

ient for hours of fun 



HI-RESOLUTl frHICS 

SENSATION^SOUIMD EFFECTS 

FAST LOADINWWACHINE CODE THRILLS 

SPECIAL SKILL LEVELS 

HALL OF FAME 




iiissiLE ii n :s 



THE ULTIMATE EXPLOSIVE CHALLENGE 




M§0 

MONSTER 
MUNCHER 

Ghosts energizers 
and a secret escape 

pw W^ W& IP* 






ANY GAME JUST 



i 
i 
i 

£5.50 I 



POST COUPON MOW TO i^B ■ 

SPECTRUM GAMES 
FREEPOST Manchester M3 8BB 

PLEASE RUSH ME A COPY OF 



authentic arcade 
action 



7X SPECTRUM 
(16* Of 48k) 



ZX81 
|16kJ 

□ 
□ 

D 



VIC 20 

|Any Memory) 



□ 

a 
□ 



INCLUDES VAT, AND 1st CLASS POST 
AND PACKING 

ANY FAULT, YOUR GAME WILL 
BE REPLACED COMPLETELY FREE 



SPECTRUM GAMES 

FREEPOST MANCHESTER M3 SBB 

SAME DAY CREDIT CARD SALES 

$ ^ 061-832 9143. (24 HOURS) 

DEAL I R I •JOUlRfES INVJTED 




MONSTER MUNCHER | 

HOPPER □ 

MISSILE ATTACK Q 

SPECIAL OFFER -SAVEONTWOH 

SAVE £2.00 ON ANY 2 GAMES PAY ONLY £9,00 

I enclose a cheque/PO. for t 

or please de&it my Access Card. 

no. naDnnnDDPaDDnnnn 



NAME..., 
Address 



FREE POST - 




TAMP NECESSARY 



I 
S 
I 
I 
I 
I 
1 

1 




APRIL 1983 




ZX-81 Ground Strike: page 84. 

$502 machine 
code serivs: 
page 103. 




MACHINE 
CODE 

Cover photograph by Stephen Qitver 



28 



EDITORIAL AND YOUR LETTERS: Lynx lovers; Dutch Dragon doubters; Swiss 
tipsters; and the Riddle's black rod. Arc micros corrupting the nation's youth? 



30 



NEWS; ZX-83, ZX-84, and Microdrive latest; Peanut — the £300 Apple look-alike; 
talking cars; computing for the blind; £170 Texas portable; £10 computer repair garages. 



37 



COMPUTER CLUB: Stopping just short of world domination, north London's 
Queen's Crescent club is spreading its message from Kentish Town to Primrose Hill, 



38 



FIRST BYTES: If you have noi passed Go with your brand-new micro go straight to 
First Bytes to collect an imroduaion to microcomputing and perhaps win £1 > of software. 



40 



DRAGON SOFTWARE SURVEY: Save your planet, slay mythical beasts, or just take 
on gorillas with your bare hands — and all in the comfort of your own home. 



BBC BUGGY: At last a robot that you can just plug: in to your computer. Simon Becslcy 
reviews Bconomatics £150 BBC Buggy — the ultimate adult toy. 

TEXET'S £98 COLOUR COMPUTER: The cheapest yet, Bill Bennett reviews the 
Hong Kong built micro aimed at Oric and Sinclair country, 

VIC-20" SNAKE: Watch out there's a killer mushroom about in Andrew Diiley's game 
of predatory pythons and violent vegetables for the uncxpanded Vic. 

DRAGON REBOUND; Quick reflexes are the key to Vincent Crockett's original game 
for the Dragon, How many targets can you hit in a minute? 



56 
60 
64 



66 



ZX-81 UNIFILE; A comprehensive filing system for the 16K ZX-81 allowing you to 

make rhe best use of information storage on cassette. 



72 



BBC MACHINE OPERATING SYSTEM: 13 may be unlucky for some hut not for 
Chris Melville as he explains the 13 sections of the BBC's MOS, 



76 



ATARI TOAD: Not jusE another Froggcr program* This time you sit on a lily pad and 
wait for the flies to come to you. 



79 



82 



BBC MODES: Fintan Culwin shows how to double (he height and width of characters 
in high resolution without doubling your money. 

ACE CHARACTER FORMING: Down with pstudcKlcsccndcrs. Roger Liddiard 
gives dignity back to screen characters on the Ace, 



84 



ZX-81 GROUND STRIKE: Philip Tyler's machine-code attack game stretches the 
capabilities of the unespanded ZX-81 to the limit. 



88 



95 



SPECTRUM DEATH DUEL; A high-speed fame ol strategy (w two players Force 
your opponents into the walls of death. 

VIC VARIABLES: Vic variables are a bit like spaghetti — difficult to pick up but a 
deliphi once mastered. Clivc Fitinis is your pasta master, 



103 
111 



6502 MACHINE CODE: A new series to help you to get to grips with how the 
Vic-20, Oric, Atom and BBC Micro work, 

SPECTRUM ANIMATION: Robert Newman's machine-code routines open up a 
new fast-action flicker-free universe. 



117 



SPECTRUM COMPLEX SOUNDS: Ronald Seniscal utilising interrupts so you 
can add fuss-free sound to your favourite games- 



122 



HISTORY OF SOFTWARE: John Dawson puts today's software in context with a 
look 3t the early days of computer programming- 



127 
129 



BASIC DICTIONARY: Tony Edwards completes his A to Z of Basic but breaks 
into non-alpha numeric symbols in this penultimate: episode. 



RESPONSE FRAME: Tim Hart- 
nell answers your computing queries. 



<n^ FINGERTIPS: David Pringle's 
U I pocket computer and calculator spot. 



133 



SOFTWARE FILE: 10 program-packed pages full of games, tips, and serious 
applications for the Ace, Atom, ZX-81, BBC* Vic-20, Dragon, Atari and Spectrum. 



WIN A TEXET: 



See card 
at page 26. 



155 



COMPETITION CORNER: New 

teasen Commodore 64 winner. 



VOURCOMHUTfcR, APRIL 1983 



DEALER THERE'S A NEW 





From now on, you won't have to look far for a totally professional home computer dealer. 

Just look for the name that says it all. COMPUTERS FOR ALL 

It's the newest and most exciting network of Micro dealers in the U.K. 

The ideal places to buy, browse, seek advice and after-sales 

service . . . professional service! 

Every COMPUTERS FOR ALL dealer is dedicated to giving you, the customer, 

exactly what you have always wanted . .-. a shop or store that knows about computers, 

capable of helping you sort out what's right for your needs; expertise 

in giving sound advice, knowledgeable in technical matters. 

If you've ever bought from the usual retailer who just stocks and sells, 

you'll appreciate the difference! 

A COMPUTERS FOR ALL dealer is a shop where people matter . . . why not 

call in at your local one today. You'll get a friendly welcome! 




FRIENDLY SERVICE AND THE WORLD'S FINEST MICROS! 

You'll find a wide range of popular Micros at a COMPUTERS FOR ALL dealer 
Atari 400 and 800, Sinclair ZX Spectrum, DRAGON 32. SORD M5, MPFII, 
Commodore 64, Oric I (48K) and BBC Micro* to name a just few! 
Plus of course, the sort of dealer who can (and 
will) explain which one is best for your needs! 




HARDWARE, SOFTWARE TOO! 

A COMPUTERS FOR ALL dealer also stocks a great deal of the very best hardware 

and software, so that you can expand into new worlds of computing. 

Everything from equipment like EPSON and SEIKOSHA printers to a fantastic new range 

of ATARI software direct from the U.S.A.! 

Of course, you'll also find lots of other items of interest at a COMPUTERS FOR ALL dealer. 

Books, BBC Software, DRAGON 32 Software . . . .^j?-^. -sec Micro amiable 

the liSt iS endleSS! ^»C_ ^""XL at selected dealers only 

Call now at your local shop or store. 
Look for the name that says it all . , . 
COMPUTERS FOR ALL 

Where to find your COMPUTERS FOR ALL DEALER 




AKHTER INSTRUMENTS LTD 

Unit 19. Arlingtiyde E stale 
South Read Harlow, Essex 
0279-412639 
ANIROG COMPUTERS 
26 Balcombe Gardens 
Hariey. Surrey 02 9 34 6083 
APHROS SOFTWARE CO, 
83 Canterbury Road 
Wesibrook. Margate, Kent 
0843 23627 

AUTOMATION SERVICES 
IS, Wales) 

3 Wermeys Road. Penystai 
Bridgend. S.Wales 
0656720969 

BITS & BYTES 
44 Fore Street, litracombe 
Devon 0271 -62801 
CARLTON COMPUTERS 

4 Swans tons Road 
Great Yarmouth, Norfolk 
0493-58898 
COMPUTASOLVE 

8 Central Parade 
St. Marks Hill. Surbiton 
Surrey 01-390 5135 
COMPUTER CORNER 

The Wickford Video Da 
15 The Broadway. Wi cater rJ 
Essex 03744-3710 



COMPUTER SYSTEMS 

ITORBAY] 

Pump Street. Brixham. Devon 

08045-6565/6 

COMPUTERS FOR ALL 

72 North Street 

Romior-d, Essex 

0708-752862 (two lines) 

CRYSTAL COMPUTERS 

209 Union Street, Torquay 

QevDn 0803-22699 

DAN EVANS (BARRY) LTD. 

81 Hollonfload 

Barry. South Glamorgan 

0446-734242 

D.V.MARTIN LTD. 

13 Bridge street. Belfast 

N Ireland 0232- 2Z6434 

EMPRtSELTD. 

5fi East SI reel Colchester 

Essex D 206 -87 0353 

EMPRISE LTD. 

3a Baddow Road. Chelmsford 

Essex 0245-355834 

EUROCALC 

224 Tottenham Co urtRd 

London W1 01-631 4139 

FAL-SOFT COMPUTERS 

8 St. George's Arcade 

Falmouth, Cornwall 

0326314663 



HOME COMPUTER CENTRE 

(ROSS RECORDS) 
13 Kingston Road, Portsmouth 
Harts 0703-819515 
IMPULSE MICRO 
SYSTEMS LTD 
6 Centra! Chambers 
Cooks Alley, Wood Street 
Strallord -upon -Avon 
0789 295819 
JADE COMPUTERS 
Coombend, Radslcck 
Bath, Avon 0761 -32570 
KELLY'S 

COMPUTERMARKET 
227 Dartmouth Road 
Sydenham, London SE26 40 Y 
01-6994399/6202 



KENNETH WARD 

COMPUTERS 

Verve House. London Road 

Sunning dale. Berkshire 

0990-22275 

MEDWAY COMPUTERS 

141 New Road. Chatham 

KentQ634-826080 

MERCATOR COMPUTER 

SYSTEMS 

3WhiteladiesRoad, Clifton 

Bristol 0272-731079 

MOBILE MICROS 

2 Castle Street, Thornhury 

Bristol 0454-418383 



STEVE'S COMPUTER CO. LTD. 

Castle Arcade Carditl 

South Glamorgan 0222-41905 

THE COMPUTER CENTRE 

(QMS) LTD. 

37d & 37e Robertson Sir eel 

Hastings. East Sussex 

0424 439190 

TWILLSTAR COMPUTERS 

17 Reg ma Road. Soulhall 

Middlesex 01 -574 5271 

WEYTECH COMPUTER 

SYSTEMS 

20 SI Edmunds Street 

Weymouth, Dorset 

03057-79881 




COMPUTERS 

irrrr 




"THE SHOP WHERE PEOPLE MATTER" 



¥)u know that Spectrum 
software is easily arfordable. 

NowWELSmith make it 

easily available. 




Meteor Storm 
Quicksilva 

16K £4.95 



Escape 

New Generation 

16K £4.95 



Ground Attack 
Silversoft 

,6K £5.95 



Orbiter 

Silversoft 
16K 



<Xm?*3t>ZSmD 



Space Raiders 

Sinclair 
16K 



£4.95 




Flight Simulation 

Sinclair 

^£7.95 



Horace Goes Skiing 
Sinclair 

,6K £5.95 



Battle of Britain 
Microgame 

""£5.95 



G YOUR COMPUTER, APRIL 1983 



When it comes to software for 
the Sinclair Spectrum, there's no 
question who's right up your street 
W. H. Smith. 

Our range already covers some 
65 programs. And it's growing fast. 

So fast that every month we 
select and illustrate a Top Ten to 

W. H. Smith Spectrum Software Library 

(all 16K programs will run on48K machines) 



keep you informed of the programs 
which are proving to be the most 
popular. 

If on the other hand you've 
already got the Top Ten then why 
not come in and browse through 
the rest ^ of our range. 



Tide 

Arcade Games 

Space Intruders 

Time Gale 

Mined Out 

Gulpman 

Spectral Invaders 

Avenger 

Metcoroid^ 

Planetoids 

Hungry Horace 

Mazeman 

Nigliiflighl 

Ground Force Zero 

Caterpillar 

Leapfrog 

Gobble- A -Ghost 

Ccnti-Bug 

3D-Tanx 

Pcnetrator 

Cruising 

Arcadia 

Derby Day 

Jackpot 

3D-Tunncl 

Gobble man 

Galax tans 

Senlinal 

Cyber Rats 

Strategy Games 

Novotnik Puzzle 

Chess 

Voice Chess 

Football Manager 

Chess -The Turk 

Adventure 

Labyrinth 

Planet of Death 

IneaCurse 

Ship of Doom 

Espionage Island 

The Orb 



Producer 



K RAM 



Quicksilva 
Quick silva 
Quicksilva 
Campbell 
Bug-Byte 
Abacus 
Soltek 
Sinclair 
Sinclair 
Abersoft 
Jlewson 
Titan 
CDS 
CDS 
CDS 

DK Ironies 
DK Tronics 
Melbourne I Ise 
Sunshine 
ie 



16 
48 
48 
16 
16 
16 
16 
16 
16 
16 
48 
16 
16 
16 
16 
16 
16 
48 
16 
16 

Computer Rentals 16 
Computer Rentals 16 
New Generation 16 
Artie 16 

Artie 16 

Abacus 16 

Silversoft 16 

Pliipps 16 

Artie 48 

Artie 48 

Addictive 48 

Oxford 48 

Axis 16 

Sinclair 48 

Sinclair 48 

Artie 48 

Artie 48 

Computer Rentals 48 




£4.95 
£5.95 
£4.95 
£4.95 
£5.00 
£4.95 
£4.95 
£4,95 
£5,95 
£4.95 
15.95 
£5.00 
£5.95 
£5.95 
£5.95 
£4.95 
£4.95 
£6.95 
£4.95 
£5,50 
£5.95 
£4.95 
£4.95 
£4,95 
£4.95 
£4.95 
£5.95 

£4.95 
£9.45 
B35 
£6.95 
£8.95 

£5.95 
£6.95 
£6.95 
£6.95 
£6.95 
£5.95 



Chess 
Sinclair 48K 



The Hobbit 
Sinclair 48K 



£7.95 £14.95 ■ 



oublr Yap* 

\ii I t. 



Tide 

Utility 

M/C Code Test Tool 

Compiler 

Family Games 

Revmi 

Othello 

Golf 

Conflict 

Practical 

Vu-Cak 

Vu-Fde 

Vu-3D 

Collectors' Pack 

Club Record Controller 

Address Manager 

DtL'tron 

Program Collections 

Shiva Special 1 

Over The Spectrum 1 

Over The Spectrum 2 

Over The Spectrum 3 



Pmduccr KRAM Price 

Oxford 16 £9.95 

Softek 16 £14.95 

Sinclair 16 £7.95 

CDS 16 £5.95 

RandR 16 £3.75 

Martech 48 £11.95 

Sinclair 16 £8.95 

Sinclair 16 £5.95 

Sinclair 48 £9.95 

Sinclair 48 £9.95 

Sinclair 48 £9.95 

Oxford 16 £8.95 

Custom Data 16 £4.75 

Shiva 16 £5.95 

Melbourne Use 16 £5.95 

Melbourne Use 16 £5,95 

Melbourne Hse 16 £5.95 



WHSMITH &» 

F\.^l ■£■ Pncijcorreclai!imcofgoirig!oprC4s.SubjcctioarailaWiljp.Alsclec(cdhratKhcj(r»n|y. ^^^^ 



YOUR COMPUTER APfl'l. 1983 



DONTMISS THIS INCREDIBLE OFFER ! 

50 GAMES £995/ 

CASSETTE 50 FOR YOUR MICRO 



fci 



ES& 



*-.*> 



CASS 



grre 



5 o 



or 



,<*i 



i&\ 



j-» 



GALACTIC ATTACK 
SPACE MISSION 
LUNAR LANDFR 
PlASMA-BOLT 

STAR TREK 
RADAR LAWOlNG 

■mt^cker 

GALACTIC MGFIGHT 

ZION ATTACK 

PVASWE ACTlffld 

OKO 

BQGGLE5 

KSNTO0N 

SKIJUWP 

hAWG^AN- 

OLD BONES 

ThJN ICE 



MAfE EATER 

Orbitteh 
motorway 

fORCE HELD 
HIM 

TUNNEL ESCAPE 

BARREL JUMP 

CANWONB ALL BATTLE 

OVERTAKE 

SITTING TAftGET 

SMASH THE WIN DOWS 

SPACESHIP 

JET FLIGHT 

MAffiEK 

INTFTUQER 

INFERNO 

GHOSTS 



SUBMARINES 

RQCKE T ;JHJNCH 

PLANETS 

SLACK HOl,i 

OVNAMITE 

00 YOUR SUMS 

D£RflY DASH 

SPACE SEARCH 

UNIVt RSE 

RATS 

TANKEfl 

PARACHUTE 

JLTUOBut 

HIGH Rl$E 

THE FOfiCfc 

EXCHANGE 



^X.^3 



T?' 1 

1**% I 



NOW AVAILABLE FOR 

Vlfr±) 

ACORN 
ATOM 

ORIC4 

SHARP 
NEW BRAIN 



sinczlaii - 

SREETRUM 

ZXB1 

LYNX 

DRAGON 

ATARI 

i_j_l_ OH DISC* 
PPPKZ CASSETTE I 



#£t^ 



DIRECT MAIL ORDER FQRt 



MINIMUM SIZE COMPUTER REQUIRED ONLY 



frasrfti>E 


SUPPLY CASSETTE SO FOft 


) SOFTWARE 


t cnctot ctoquc/P.O. OS please debn my 


| CASCADES HOUSE 


Access BudaycardNo 


| BARGAN'S LAME 


Name 


\ UANDOGO 


Mdkcn 


1 GWENT 

[ S,WALES NPS4PA 










hs&M 



COMPUFFftl 



The Samurai* 
home computer 
is coming... 



*Samurai is a trademark of Samurai Worldwide Ltd 



6 YOUR COMPUTER. APRIL 1983 



100 FREE PROGRAMS 

FROM SILICA SHOP — WITH EVERY PURCHASE OF AN 



ATARI 



!3?sHn;9 






fe 



REDUCED PRICES! 

We n Silica Snap are pleased to announce some 
fantastic reductions in the prices of the. Atari 400 800 
personal computers. We believe that the Atari at its 
new price wifl Oecome the l/.K.'s most oopuUf pee 
sonal computer and have therefore set up the Silica 
Atari Users Club Thus club already "as a library of 
Over 5Q0 programs and win your purchase o' a 400 
or 800 computet wt wiJI grve you the firsl 100 'fee o' 
charge. There are also over 350 prof esston ally writ- 
t*#i g»m*s ind utility programs, swim its listed 
below. Compfete the reply coupon and we'll send 
you lull details. Alternatively give us a ring on 01 -301 
1111 or 01-303 1111 



ATARI 400 

with 16K 



£159 



ATARI 400 

with 48K 



£228 



ATARI 800 

with 48K 



£349 



400/800 SOFTWARE & PERIPHERALS 

Don't buy A T.V game 1 Buy an Atari 400 personal computer and s game cartridge and that's all you'll need Later on you can buy the Basic 
Programming cartridge if 35] and try your nand at programming using the easy to ream BASIC language. Or if you are interested in business 

iprj confins vfu. ,-,!■■ buy the Atari 8C0 ■ Disk Dr vt I rVintti tofttksi wftti • tali ■.' dI Lu.i rwu padugst 

Silica Shop have put together a lull catalogue and price list giving details of all the peripherals as well as the extensive range dI software i hat is row 
available for the Atari 400 800 The Atari is now one oF the best sunported personal computers Send NOWfof Silica Shop's catalogue and price list 
as well as details on our users club. 
THE FOLLOWING IS JUST A SMALL SELECTION FROM THE RANGE Of ITEMS AVAILABLE- 



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FOR FREE BROCHURES -TEL: 01-301 1111 



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FREE LITERATURE 

I am MEtrntad ■> pu'thjirtj an At*ft *00 »» corrp-Jtw >nd 
wfl<AH*,i » r*c*v* oopw of yo«f brodwrt* »nd l«I rtpors 
» W(i w V4vf pric* kH covsnrtg M Ql rh* *v*k*6*r HarAW* 

and Sortwam: 

Nmm 

Ad(Jp*.l ........... 



•'Wiiilr 



illl nil 



F>D|.lC«d« 



VCtHO — foui ComtujiBf — April 1983 



VOUR COMPUTER, APRtL 1 963 9 




It can do a powerful job for yoi 



SPECIAL LIMITED 
OFFER 

Buy just any two prosrams at £19.95 
and take one at £19.95 

FREE! 



CASH BOOKS ACCOUNTS 

PROGRAM FOR 

BBC MICRO. . X95.00 




**«*! 



One of the most innovative business 
prosrams on the market. Most serious 
accountancy packages arc written and 
coded by professional and competent 
programmers. The Gemini Cashbook Accounting 
program was written by practising Chartered Accountants and 
coded by professional and competent programmers, This is a 
fundamental difference 

This practical program is simple to use and will replace your 
manual cash and bank records and by giving you instant 
management information, it may even put your accountant out 
of job! 

Witri exceptionally exhaustive user documentation, full 
technical back up and product update policy this program will 
increase the efficiency and profitability of your business. Take a 
look at the information this program will provide, 

* summary of VAT information to enable you to complete your 
VAT returns 

* cumulative receipts and payments report analysed over the 
standard profit and loss and balance sheet heading. 

* option for departmental analysis of sales and purchases 

* print out of all transactions 

* journal routine for entering transfers between accounts and 
year end adjustment for debtors, creditors etc. 

* year end trial balance 

* profit and loss account and balance sheet 

These statements can be produced at what ever interval 
you require e.g. monthly, quarterly or annually, 

Coming soon:- Integrated Saks + Purchase Ledgers 



". . . the systems worked immaculately 
when tested , . ." 
"Mailist Is a very professional piece of software , 

OMiich Mao A Software Review Feb 83) 



Here's a range of software for the independent 
businessman that's designed to harness the power of your 
micro to deliver the vital information you need in all key areas 
of your business, A breakthrough on both price and 
performance, each program is fully tested and comes with all 
the documentation back up you need. 



"Gemini's range of software is in the vanguard of 
the releases for 'serious' micro users . . ." 



■;*%<h Mrtf a *nd Saft**rr Pt*vi*v» 





SPREADSHEET ANALYSIS 
BEEBCALC £19*95 
DRAGONCALC £19*95 



FOR BBC AND DRAGON 32. Spreadsheet 
0*M processors have proved to be important 
____J tools for ustns micros in business, scientific 
and domestic financial applications. 
Without any programming knowledge at all, you may:- 

* Set up a computerised spreadsheet, with chosen row and column names. 

* Specify formulae retating any row or column to any other, 

* Enter your source data end have the results calculated. 

* Save the results or tape (or disk - B6C) for tater reloading and manipulation. 

* Print the tabulated results in an elegant report format. 

* Experienced users may access saved files and write their Own reporting or 
graphics presentation prosrams for the results, 

Some typical applicatiortsi- 

* Smalt business accounting applications, eg. profit and loss statements and 
cashflow projections, break-even analyses etc. 

* Investment project appraisal - anything from double glazing to oil rigs? 

* Comparing renfc'>ease/buy options 

* Processing the results of scientific experiments, or field studies 

* Engineering calculation models 

* In fact, anything that involves repeated re-calculation of results presented in 
tabular or spreadsheet format 

Program Availab H ity Chart:- 





Dtovtom 


■: atM 


RAM*! 


• ■■•-<■, K 








MBfioM 


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ur business at petty cash prices. 




INVOICES AND STATEMENTS . . . £19,95 

Compatible with most micros. See table, ideal for the small 
business A complete suite of programs together with 
generated customer file for prod utirvj crisp and efficient 
business invoices and monthly statements on your line printer. All 
calculations include VAT automatically, and the program allows your 
own messages on the form produced. This program gives you superb 
presentation and saves time on one of the most tedious tasks in the 
office, 

COMMERCIAL ACCOUNTS . . . £19.95 

Compatible witti most micros. See table. A gem of a 
program, all for cassette, with the foll0win3 features:- Daily 
Journal, Credit Sales Cash Sales. Credit Purchases. Purchases 
- other Sales Ledger Purchase Ledger. Bank Account, year to date 
summary. A fulry interactive program suitable for all businesses. Files 
can be saved and loaded and totals from one file canned forward to 
**'"■ *' ;r on cassette. Particularly useful from a cash flow point of view, 
> immediate accessibility to totals for debtors and creditors Bank 
supported with entries for cheque numbers, credits and, of 
:, running balance. 

MAJLI NG LIST. . .£19.95 

Compatible with most micros. See table. A Superb 
dedicated database to allow tor manipulations of names 
and addresses and other data Gemini's unique 'searchkey 
system gives you a further ten 'user-defined parameters' to make your 
own selections. Features include the facility to find a name or detail 
when only part of the detail is known, it will print labels in a variety of 
user specified formats 





□ DATABASE , . . £19.95 
Compatible with most micros. See table. The program that 
everyone needs, the most valuable and versatile in your 
collection Feci titles include sort search, list print if required. 
Cen be used in place of any card index application; once purchased 
you can write your own dedicated database to suit your particular 
needs with a limitless numbered entries on separate cassettes. 

STOCK CONTROL . . . £19.95 

Compatible with most micros , See table. Dedicated 
software with alt that's necessary to keep control of stock. 
This program will take the tedium out of stock control and 
save time and money. Routines include stock set up, user reference 
number, minimum stock level, financial summary, line print records, 
quick stock summary, add stock, delete' change record and more 

HOME ACCOUNTS . . . £19.95 
Compatible with most micros, See table. Runs a complete 
home finance package for you with every facility necessary 
for keeping a track of regular and other expenses, bank 

account mortgage, HP. etc. This program also allows you to plot 

graphically by Ustogrems your monthly outgoings 

ri WORD PROCESSOR . . . £19,95 

Compatible with most micros. See table. This program 
features routines found in much larger and more expensive 
packages with a typical word length of 5-6 letters it allows 
for around 1 000 words m memory at one time. Ideal for the user who 
requires a simple program to write letters on his computer. Features 
include, btock delete, block insert, search and replace, edit text, display 
text and more. 





Dealer/Trade enquiries invited - generous trade discounts for quantity 
Special ACCESS card instant sales hotline TW|* A^ORO C4 *£C 
for GUARANTEED despatch within 24 hours . . . 161 ♦ U^7JX K J I OS 

24 hr Ansaphone Service. 

All enquiries other than credit card sales to 03952-5832 

Gemini. Functional Software Specialists. 9, Salterton Road, Exmouth, Devon, 



i 
i 

i 
i 
i 
i 
i 



Tick the box tor Program you require. Prices include VAT and PacJtage and Postage 
Please supply the following cassette software, 

Database ._._ ._ £19.95 n 

SUM* Control £19:95 P 

Mailrg Lest , , „ £19.95 1 1 

hvotte* v& s»t*rf*fitj . £19.95 □ 



ZX61 if* Database 
BBC Gun Book .ww 



Commercial Accounts , 
Home Accounts 



..£19.95 P 
_ £19.95 P 



BBC Disks - other title* . . 
Osborne Otik Database 

Word prrxCMOr 

Seebeok: .. 

DrsgarcaJc 



. £9.9$ U 
. £95.00 P 
CS3 9i :'\ 
.£83.9$ a 
£19.95 P 
£19.95 P 
£19950 



Home. 



Adorc«_ 



Machine typc_ 
IcnctoK 



Memory Sj«_ 



Make cheque* and postal orders payable to Gemirb Martetirg Ltd 



fine ps Card Number 



jAtceis Number 
Sinistra 



ll}3S^%~, JJ^J 

Gemini, Functional Software Specialists, 9 Salterton Road, E xmo u th , Devon. 




\ 



4llT$L J 



Push your Sinclair to the limit 



ZX81/SPECTRUM 

ARCADE GAMES 



^^<Ti ZX INVASION FORCE 

TOWjL— " Use you r ski 1 1 to fire though 
V***"*^ the energy band to destroy 
Ihe merqcinq niien ship — 
^ p ^- E3.95 
-"t?\(\l SPEC INVAOEttS 
Wr.]J> SPEC GOBBLEMAN 
\_^-^"*' These exciting high- 
speed classic games 
incorporate hi -resolution graphics and 
sound to bring you (he best in arcade 
action al only E4.95 each { 1&48K) 

^^~- SP EC FHOG 5JS HO W D OW N 
^tSN <16.48K) 
Mr, \Z* Hop across the dangerous 
•^■-•"■"""^ road avoiding the lethal cars, 

then lorries. Go back to Ihe 
wi id west for a gunlighl battle amongst 
cacti and wagons. Features include 
western music. £4.9 B 

^^^-* NAMTIRRAIDEnS<2XG1) 
^"iCVftl HlQf1 s P eed - quick action 
^At :*ji- arcade game with four 
*^**-"*"^ separate groups of attackers. 

GoBble-Tiam a 1 so avail *We tor ZXfli ai £3 91 



THE ULTIMATE ADVENTLJHE FOHTHE 
SPEC T RUM/ 2X81 tor only f 9 95 

FHOrVt AHTIC -\^fj 

has left you £ 10.000 in Pit! *i II In ofOBf lo ei Birr your 
wifuJtaiiytnj fTiusi iotv* twtive dues and gain 

KCC33 !0 * Dili! account in wtlictl tnrj mOAfy hit 
actually txrei deponled Bs lTia firsl Id crack Iho 

puLi'e ana 1he jjcre js j-oufi! Plus you Mil win Iwa 
[ickeli !o PP-* city al the secret KRAKlT' w *iul| 
local ion TP># Prize money if irtCf«aMK) ws*K4y. A 

telephone n umber -a i 11 be supplied so you ha** tPie 
Opportunity "o lir>d oul | uil how muc h you :n u Id *i n 

DON'T MISS 

YOUR CHANCE TO WIN 

A FORTUNE! 



UTILITIES 

TOOLKIT 

Nine powerful new (unctions for 
your ZXfi 1 (including re-number 
lines (goto, gosuD), pfOfiram merge, 
string finding and replacement, £5.95 

SPEC BUG 

A 30 1 n i machine code tool and d I sassembl er 

for your ZX Spec I rum. £6,95 

ZXBUQ 

A 30 In 1 machine code tool ana disassembler 

lOr your ZX81. CS-95 




Improve your machine 
code programs with this 
new 48K Spectrum 
Assembler 

Just released by Artie, this new profess tonal 
quality assembler is also available for 16K 
ZX81 and features:— 

•Word-processor-like text editor. * High 
speed, versatile two pass mnemonic 
assembler with labels and detailed error- 
trapping Will assemble to any address. 
* Essential support facilities such as 
memory -edit, register inspect'modify and 
search for de- bugging, ■ Full output to 
ZX-prinler * Memory. si atus 
report and comprehensive r-n *"«- 

usef-manuai. ONLY I_t).i70 

ZX81& SPECTRUM 



SPECTRUM 

MICRO CHESS 

Tne only Choi s ptoQram tor i 16K at tSKSp*ettttm 
A)IOW« *H leg*! mo^frS. C«Wl Mng:eA-eU9an| 

and pawn promotion. 

Option* to play D.'acK, o r *rni te Sel s 

board ;n &•> y po*l 1 1 *n . Full colour 

«ndgr*»tiic*ili>til«y. 

ONLtr 

£6.95 



NEW LOW PRICE * 
# pjDVENTU/?^ 

^ GAMES c & 
O ONLY £5.95 for ZX81 
and £6.95 forSPECTRUM 

1NCA CURSE [MwitureB, 
In a jungle clearing you come across an 
ancient inca temple Your mission to enter 
collect the treasure and escape alive. Bui 
beware' includes a cassette save routine. 

SHIP OF OOOMlAdvonlMraCl 

You are unavoidably drawn to an alien cruiser. 
Can you reach the control room and tree 
yoursel f "? Or wit I they get yr>u f if St ? I nd udes 
a cassette save routine. 

ESPIONAGE ISLAND < Adjure ai 

While on a reconnaisance mission your plane 
losas control and you are forced lo land- 
Gan you Survive and escape with Ihe island's 
hidden secret"' 

PLANET OF DEATHtAdvom^Ai 16/4SK 

You find yourself stranded on an inhabited 
alien planet. Can you teach your ship and 
escape? 

>^£\ ZX FORTH 

^pPr.l nu'^ Supplied on cassette 
with editor cassette, 
user manuals and keyboard over lay, ZX Forth 
combines Ihe simplicity of basic wiln Ihe 
speed ol machine code now £14 95 





'SKCTftUM 
CHESS 48K 



SPECTRUM 

INVASION 
FORCE 

A popular ircaflo cam* fo* l<GK or *BK SptKtrum 

Fre* 1hrp«flh the rorc4 TmlrJ CO 0*S"'Oy th» 
menacing alwn ftTup SQuhds ea^y' 1 T*o Imwts ot 
0»iy — normal Ot SuiCtdai Full colour Sflund and 

ttitt graphics 

NOW ONLY £4.95 



ALWAYS AHEAD WITH ZXSl/SPECTRUM SOFTWARE 

ARTIC COMPUTING LTD. 



A 

GREAT 
CHESS 
GAME FOR 
YOUR ZX81 
OR SPECTRUM 

ZX CHESS I 

Very popular machine code program, with six 

levels of play and an analysis opt I on Available 

forZXW.nJQ 

ZX CHESS II 

Anew improved version, *rlh a taster response 
time, seven levels of play, analysis option and m 

Sddrtion a Tecommendod move option, E9.9B 

ZX1K CHESS -rr 

An Incredible game " _ feQlyjt&i&R _L- 



in tK for only £2.95 




SPECTRUM 

VOICE CHESS 



TrH» incrMibM program lalhr, you 

ttvi uflhyouratiM 
1 1 rnova. rpctKiiTwudi « rntrv*. trm 
COOtwns a range ol Ifttuiir*! s cormnenta t r* gam* 
t* CtlMd on trw higniy suce««*1iil ZX Cr«s II and 
<4 Olteredat !PU? C^" r/rras frffer OfKprj' E9.BS 



SPECTfiUM CHESS now only £9.« 



CPiwjues 4 P O made payable to: ADlc Compollmj ] imit»d tValff enquints w*ICOrr-e 
Please stale *rn>! he youf/Of (W Is for ZXB1 of Sp*c trurri. Sand S. A E (61 n :■: 9i nltor calalogy • 



To: Arlic Computing Ltd . 396 James RteMt Avenue. 
Hull. N. Humo*r»lo>, HU« CJ*_ 

Pl**t*tupp4y 



396 JAMES RECKITT AVENUE, 
HULL, N. HUMBERSIDE, 



CrnX|iie (SI total anlOunt tncloUd, 

Nam« . . . 

Addtesi . . 



VC-4 



1 2 YOUR COMPUTER. APRIL 1 983 



TELEWRITER 

the DRAGON 32 Word Processor 



TELEWRITER 

Telewriter is ihe powerful word processor 
designed specifically for the DRAGON 32 
Computer, It can handle almost any serious 
writing job and is extremely easy to use. It 
has all the advanced features you need to 
create, edit, store, format jiiuI prim arts- 
kind of text. With Telewriter you can 
quickly produce perfect, finished copy for 
leuerc, reports, term papers, articles, 
technical documentation, stories, novels, 
screenplays, newsletters. It is also a flexible 
and efficient way to lake notes or organize 
ideas and plans. 

51 x 24 DISPLAY 

The DRAGON H is an incredibly powerful 
and versatile computer, but for text editing 
it has some major drawbacks. The small 32 
character by 1 6 line screen format shows 
you too little of the text and, combined with 
its lack of lower case letters, bears linte 
resemblance to the way texi really looks on 
the page. Reverse video in place of lower 
case just adds confusion. 
Telewriter eliminates these short comings 
with mi hardware modifications required. lis 
using software alone. Telewriter creaies a 
new character set thai has real toner caw 
lellers, and puts 24 lines of 51 characters on 
the screen. That's more on-screen characters 
than Apple U, Atari or TRS-80 Model lit, 
Thai's more than double the DRAGON 32*8 
standard display. 

FULLSCREEN EDITOR 

The Telewriter editor is designed for 
maximum case of use. The commands are 
single key (or single key plus control key}, 
fast, and easy io remember. There is no 
need to switch between insert modes and 
delete modes and cursor movement modes 
You simply type. What you type is inserted 
into the tcx i at the cursor, o« the screen. 
What you see on the screen is always the 
current stale of your text. You can move 
quickly through the text with one key cursor 
movement in all 4 directions, or press the 
shift key simultaneously for fast, auio- 
repeat. You can jump to ihe lop or bottom 
of the text, and beginning or end of a line, 
move forward or backward a page at a time, 
or scroll quickly up or down. When you 
type past the end of the line, ihe wordwrap 
feature moves you cleanly to the ncsi. 

You can copy, move or delete any siae block 
of lext, search repeatedly for any pattern of 
characters, then instantly delete il Or replace 
it with another. Telewriter gives you a tab 

. . . twtvu ttott qf tht art wt*nt 
protestor . . . ituismndirtg in every respect 

- The B A IN BOW. }j/i |*t2 



The only one with all these features 
for your DRAGON 32 

51 column x 24 line screen display 

Sophisticated full screen editor 

Real lower case characters 

Powerful text formatter 

Works with any printer 

Special MX-80 driver 

Requires absolutely 

no hardware modifications 

* Tandy colour version 

also available 

key, tells you hov, much \pave >*»lj haic leu 
in memory, and warns you when the buffer 
is full. 



FORMAT FEATURES 

When it comes lime lo print out the finished 
manuscript. Telewriter lets you specify: left, 
right, top, and bottom margins, line spacing 
and lines per page. These parameters can be 
set before printing or they can be 
dynamically modified during printing wilh 
simple format codes in icxi. 
Telewriter will automatically number A4 
pages (if you want) and centre lines. It can 
chain print any number of text hies from 
cassette without user intervention. You can 
(ell it to stari a new page anywhere in the 
text or pause at the boitom of the page. 
You can print all or any pan of the text 
buffer, abort the printing at any point, and 
there is a "Typewriter" feature which allows 
you lo type straight to your primer. Because 
Telewriter lets you output numeric control 
codes direct ly (either from the menu or 
during printing), il works with any printer 
(Tandy, Seikosha, M.VBO, Okidata, NEC 
S023. C. Itoh 8510. Centronics, GE 
Term in et. Smith Corona TP-I , etc.}. 
There's even a special driver for the Epson 
MX-80 that lets you simply select any of its 
12 fonts and do underlining with a single 
underline character, 

CASSETTE INPUT/OUTPUT 
Because ihe Telewriter makes using cassette 
almost painless, you can still have a 
powerful word processor without the major 
additional cost of a disk. The advanced 
cassette handler will search in the forward 
direction till il finds ihe first valid file, so 
there's no need to keep retyping a load 
command when you are lost in your tape. 
The Verify command checks your cassette 
save io make sure they're good. You can 
save all or any part of ihe lexi buffer to 
cassette and you can append pre-existing 
files from those you have in the buffer 
alreadv. 



ASCII COMPATIBLE 
Telewriter turns your DRAGON 32 into ihe 
niOM powerful, lowest cost, word processor 
■n the world loday. Bui ihats not all. The 
simple ASCII conversion program provided 
with Telewriter means you can use the full 
powct of iht telewriter editor tor creating 
and editing BASIC and assembly language 
programs, li means you can use Telewriter 
to prepare qr edit test files used with any 
data communications program. 

Telewriter costs £49,91 on cassette and is 

AVAILABLE FROM 
DRAGON 32 

DEALERS 
NATIONWIDE 

OR DIRECT FROM 

M1CIIOMAIL 

41 TRURO ROAD. ST. AUSTELL, 
CORNWALL PL2S SJE 
24 HO UR OROERLINE 0726 67676,- 

• - iyi ^Zm& 

^sendforourTreT i 
software lists for 
dragon 32 & tandy 
range of computers, 
please state which 
computer you own 

Name 



Address. 



Make j type of computer 



| Please include a 1st Class Stamp! 

. tutt' nf ihe fttfl progrmits fur lire Cttitir 
Computer / have .vren . „ . 

- Color C'OinrwKrr Sfm, tar. 198.1 



Apple II is- a trademark of Apple Computer Inc.. Atari is a !radomarkof Alan, Inc.. TRSSO'Sa trademark ol Tandy Corp.: MX-80 is a trademark of Epsoi America Inc 

DRAGON 32 is a Tradamafk of Dragon Data Ltd 



VOUH COMPUTER. APRIL 1963 13 




NEWS 

from SPECTRUM 



ATARI 800 



This proven and tested micro is now 
UPGAAOED to 4$K RAM and there's 

no Incfc.ise in price either whith IMUSI 

make 11 about the best value around 
See our ad loi lurlher details 



ATARI 400 



Now REDUCED by a MASSIVE C39 lo 
an incredible price ot only £159.95 
from Spectrum. 



SINCLAIR ZX 
SPECTRUM 



We have now added the super 
SINCLAIR ZX SPECTRUM 16K and 
48K Models to oui tango - check our 
ad. for further details 



NEW SPECTRUM 



Checfc otlf address page! - there are 
many now SPECTRUM dealers 
throughout the UK so there's a good 
chance there'll be a SPECTRUM 
centre very near you. 



STOCKS 



The general stock situation has now 
improved and you'll find (hat must 
SPECTRUM centres will be able lo 
supply you Immediately and at super 
LOW prices tool 



INTRODUCING 
SPECTRUM FACTS 



Next to many of Our oflers , you'll 1 ,nd a tow 
lines lagged SPECTRUM FACTS, We pride 
ouranlvai on providing you, Ihe customer, 

With a g*nulne sefvicB as well as Super 
LOW prices- and we want you to know 
that wlt«n you buy from a SPECTRUM 
dealer, you'll Qot aigctiy the nc.ru Micro 
for your need*, SO LOOK OUT FOH YOUR 
SPECTRUM FACTS! 



fitter Soles care 



JPICtftUM lerVICI irl'lip! n -II Miyil th«,l 
ihllMtlur ruckm* "g.i d-rtn »( mil (11 i| 
tunning ifiin 411 auicklr in piiiibl*. Vf 'h& 
t>Uti otinrJid wiirintm Jl rtJiomtlt p 1 »t* ( 
IS«' *!k 1 oi>r SPEClflOM HOME COMPUTER 
CfHtKI Per lull ttlluj 



COMPUTER DEALERS! 



t»r prpipmirii Computer Dealers!} If iw would 
tiki t» know mm* jhtui Jieteniiij * SPICTflUM 
AF P 1 N 1 f FJ [ ME fl or, 1 « ■» Make *■*■ *a»i.. 
pluu Willi to MIKE 51EKK. Spectrum ill K I 
Ltd., Berrowiiild, Wilwyn Gird in Cur. rttrt*. 



COLOUR GENIE 



A truly reliable micro 
and highly recom- 
mended by Spectrum. 



" m ■ m— * im i f m w — ■* m r, - 




Spectrum LOW Price 

£224« 



COLOUR GENIE ACCESSORIES 



tN ppw COLOUR GENU liilurfi plnnM ml 10+hnr.itJlrJ COIOUR GflAPHlCS *l{o»u»| 
tow Hi (itHi lull 1 cdHC t>l>«1. Dumi »M Cmtl qai<l!f »<■ unylj 

Al 11 !m SPECTRUM pnet, tfce Collar Gnu n ntmfly vkmIiIb - >n PeviKl«l It I RAM 
mimer, I*i3«<rtr» lalwMlrf U 3ItSt-lKH MUCOiQUN til.. ■■■■? Md FflWCAfUL COM- 
PUTING miis ■ 1*11 fuji el lurpeaiM iccntvnti 1»K MM list. Jonlicki (01 IV gjtnti. 
Light Pi*,. Oil* Of 1*1 In4 1 Pnour 

fim Itiil 1 no] ill • Ihi Call * Clan '111 teileMi 1 lift ROM MiHIIt mlt lit Upper liul Lower 
tin CbIbbi BuBBicf CkaiiClpn J ipidv iloipd plui iDBnd 1 j« j'ftl'-sril lyivnrilpl kpfDOitd 

la HI. ill II ilmgarfiiiniiJ |i ia| triinki :g Ikf m n1 BASIC U14UJ31 ird duct! tiTtianl 
i;(tnH ciIhm cmiBiMti 

Ihi tufprbCekfi Gift it H JP4CTSUM no* (Mti it lit ip* 1 tei tki Cinot 11 *<xfcl 



Joysticks,., 


r«.« 


16K RAM 


. £38 SO 


Printer Inter F He it 


£39.95 


VISCOUNT Teach yOurt.aH Colour 




Genu BASC 


CS.9S 


SPECTRUM FACTS 


Maximum u60r RAM. . . 14.200 By-lea JjipprAx) 


Toxl Scropn 


24 x 4L 


Hiflhftesotudon, ... 


, ISO x. 96 


Cassette Lead. 


. Included 



ORIC-1 






. 







J»| ':ak IT iNni mpn Bin I THX Mnr« in intndihli l(k + 3JI ijn ui |4i 
I'll! 1 |i|LlaM>h op rn ■« bifleit i(K lei (ail fZ7b IFJ INCIUDING VST ■ p 

LfiE 11 unnismlli riiiflilr i',1 IfMX'i '*«■»*' ttMettimi mi limits 
tfiu Tr.r kijh <<l'nin»p> »l*vi (iipRtii nit* ii * itt-ttlH cane* 1«r r*« 
Mbm n lllitt !n,th nr»HMI, lk< LTSX h*b tilCPr jl U r.>HMlf 1 per till 
nrrdiiiiCiiMi') liii ilwV illUa LfMX I Alnlrtllt bmim1-:r- SPlCfmilM 
til [lull I.htri IB LhllV UMl pMUMII kslBf* nikiAf t JtafMi 11 it,n «t* 
HCMei « bennJ li b< 1 |int liBHl. 

Speclrum OOOI a 
LOWPiice %£.£lJ 

VISCOUNT Teach yoursellLYNX BASIC E6.95 

SPECTRUM FACTS 

Minimum user RAM 13,700 Bytes (appro*) 

Toxi Screen 24 x 40 

High Resolution 265x240 

Cassette Lead. Included 



mgarjfaswB»B*«Mi»««B 



*_ i a I *+_ «■ j i- ^ 

^■■■■/■PWM:*«f|i 



A tvptrtlr tltirjAHl »fid tnflimirtd mien ind frtal nl-ut loronfi* T 
frem SPECTRUM. Qitmng UK MM Colour |2 toitjieund jnd { 
bKijrsmid can ti dii^tiTfrJ at nmt lint) Hilh rnolcliori ajriphin 
U**r definable Grapbict, Fltl ssund |& atlirn of «ntrpll»1il« 
[Dunfl.l iaty lo oil kiftiBird with murine kif*. Stirnfurrl Cin 
Ironies parallel iatirfica tllrjwt ojiy CMniiliein la ■ widt ring* 
lunge it prmllri Ut 



Specltutn 
10W Price £ 

SPECTRUM FACTS 
Maximum user RAM. 

TftKi Screen .,,,..,, 

High RGSolLfllOfi 

Cassette Lead 



169 



.95 

Inc. 
VAT 



4f*,87{> Byte* 

28x40 

240x200 

Included 



JUPITER ACE 

Outstanding valua-tor-moneylTlie JUPITER ACE uses easy lo understand 
FORTH language. Connect! to your own TV. 3K RAM expandable lo 19K. Full 
moving keyboard with auto repeat and caps lock. Full *ound and chunky 
graphics. II you've wanted to learn an impressive Language then this is 
Ihe machine far you. 




IfSfVBBI 
lllllll 



Spectrum 
LOW price 



£89 



I tic 
VAT 

£76.22 flivat 



SPECTRUM FACTS 
Maximum user 
RAM 1.000 Rytea 

appro*. 



HURRY! Limited stocks only- 




M0M ■ ■ - 




U>h*li(.ihlt uba )l a»1f(13S.3ilrfi» tKtldtlll! tnm!i fc»ll Hi 
dun'nl rl i ««* »1 flit watt i»rwi4*»'» ■urn is ipfrir for qvii «"<* 
Inn lili'in Ik I lui -ftlid* higMr rt«*»tf * lalnr sttE-Mci Jrnl rut 
■I ikn lc-p ifiitititthll faniihl iijrdir* 12a, RiM iij; infill 1* UK 

*T'»U ■ * - llt '-' i nioltHiM DibJ'i! ■ Utr-iti "'t'itsK wl«f 
JAS'C 1*1 sUndaiJ; ■ »d>ji>[n: Khnd <*1* 1 til net J Sf t«nn 
B Frg1f;]ipnjl il, • ldjli*j i{ |i;raCl I ni iUi ru j (umir! ■ Prg 
1tllltn*l (iilil) HiIdjJ. ■ CrnlrB<ii£t Pjulltd frimUl ifittrlaci 
| SiriUf piofluwinuirr Ihi 8*511 U Ifc'i ma**i'I u linrln So H*i»! 

tt«t« <* aKhiiri c*ttu« 1 Imiilhi B"[f'B Out) »i^ni am mil lit 
itccrdti. ■ iitidad fiit 'j**IIisi OK t*J>£ 



Spectrum 

LOW 

price 



£ 



199 



.95 

INC. 
VAT 



SPECTRUM FACTS 



Maximum user RAM 
Text Screen , 
High Resolution 
Cassette Lead 



29,673 Sytis 

16*35 

25* x 193 

. Included 



ACCESSORIES 

-■■r-( r*» F-> " 

Caiiaitt Ua: 

CARTRIDGES 
Britik 

[atmie hitdlU 
Mtltrairii 
GfcpH Attack 
CHl Hiimit 
Slailhip 

Cltarnfhai 
EMfffTH 

Cll u? iilanik 
liiiprnt Amntatai 
Oahii 



VAT 

lll» 
E13& 

{\Til 

It) IS 

(31.19 

mis 



INC 
VAT 

f 2 TO 

£1S 9E> 

flMb 

iid as? 
£2*.9b 
£1! -95 



Madhfttafidlh* 

WlIVDllU' 

ii ampin ham 

\}:n^n Mj ill 1 1 
Pi 1 15i> 4 1 Fini!i[« 
fliagan Msl-iU n 
Typing Tutdf 



M.St fits 



£491 
EB91 

£6 91 
(Ml 



£795 
£795 
(7 9i 
C7 95 



ili.jS us li 




ft.si 
fin 



£7 95 
[Mi 



Black SificiM* f* »t 17 Si 

VISCOUNT Soft- 
ware for DRAGON 
Teach yourself Dra- 
gon Basic , . C6.9S 



% RAM M 

*T^ and if ill at the mam* ^^ 

^Qt LOW price! *^T 




New |hii }iBKM and I(i1*e Ptthilt hu b«fl uMHSti Hi * nutitl UK. RAM lilt U' i Hill r.X» 
immn|LOWp)»Lttf f J91 . If fi ruin SPECTRUkl.il ihi ifkal Horn* Micro let g^ptntt.adutatiaml 
and panoral fmaisn tic vi« and it will taka ¥su Iiib itamir) tip tt until bunnaii att. Tan ;m 
add pfmiBii. pi n gum rmordtri. dtih druti and mora, la tipafid f«ui micfB at anrJ whin taa want, 
id mil y<3'J' niitji.. Se i1 youra laslmj ler a lap-Gl-tht-ltn* micm iau mail he Iha ATAfll 800 
wiihASK .>! SPECTRUM -HOW I _ . _„. _ . 

fflST Sp«.n. m LOWPHc. 



£399 



.99 



ATARI 400 



16K RAM 




NOW ONLY 

£159 



INC 

WAT 



8 ASIC cartridge extra 

E39.99inc,VAT 

(EM. 77 ex. VAT) 



SPECTRUM FaCTS 



Maiiir-Lti mt" HiM \1.113 Brltl 
'ftilh banc t*nii<!a*l 

Tt^t Sdtun |4 H 4Q 

High KimliiliaB 3ZDx If 2 

CiUitlt Litd NifduHr Heiwiu 

ATARI DISK DRIVE 

C299.00 SI, 



spectrum 
facts 



ACCESSORIES. BOOK & GAMES for ATARI 





1 INC. 




" V.A.T. 


Waiinum ntJ RAM 


J7.JS9 B»lf l 


^tsE S:rttn 


?+* 40 


H:fth Rllslii' L l«« 


133 > 1S2 


Ciiullt Li ad 


Ntf rii etffl Kttw dir 



Accttiartit 

fhtr.il jl P*inl»l 
tOK RAM Pjci. 
404 KtiCrjiid 
32KFfW6isjrrji:tl5STlfft| 
JK RAM hen* 1*00 80(11 
PtiMin iPtu; 
Jofil-cli rjfm) 
1,'D rjDit 
h nF.tr Ciftle 
Mn.inoi Ljblo 
Thtimal Pip«( 
PnifilniaiHr J«fif,i[i| 

OuiihihiDl Jd^ m(l.i 

Ktfb«»r«j f(J A| in <flO 
Ootlit & MinMtla 
Wi,l<t Minujl 
Btiit Rt In i net Mimil 
DDS.JMinajl . 
Dpiiitmf Si litre Luting 
DOS.iSlitititiLiliins 
Home Cflmnultr Progrtnu 
Word PlM*tl«i iCiin 
Hertgjft A iuin 
M>ckieIi 9mic ',Dm*i[*|i 



INC VAT 
f 198 15 

r&soo 

159 « 
t/h tii 
tSSj.OO 
fll.M 
111.91 
tli 9 J 
(JISB 
(IS.OO 
E4.0D 
111?? 
H4S5 
E0DB0 

Nd VAT 
No VAT 
Mb VAT 

No VAT 
No VAT 

KitMOIItc* 

ESS.S9 

F14.94 
EBS.S9 



Horn Sudf ; Ciiitll * titeji I whu i si ntd) 



INV. to pfccrjrpmmj ; 
Ini'i'. tn piDQiammirig ? 
INV. to- praflHTimiitig J. . 

Cnri,irsi1igni! FrtKli. . 
in-'iiist1i.)n*l Gtimn. 
[D-iiruTunik ltlli»n 



£1S?9 

il2 3U 
£22.39 
(IS S3 

qui 

1H 99 



CMrtrMtetl Spirnh {J9 39 



INC VAT 

turcptjn Cptnlriii h Cibi £14 S? 

Hjrgmin EtA.SU 

Kir-jdnm ... . £li4.S9 

Siaiti A Cap n lis C14.» 

Tooth TYP'n« £19.19 

Mynt CenpBitr iCirlndftf Hi S9 

Homi IntiminmrBt iCirifldf* *ictBl 
ntitia ■! tirr a 

GtUtiin £29 99 

OtlMdti . £19.19 

AititoiBi . . £29.90 

tbifctlbbll £24.95 

QlxtjiEk iCHMltil £14.94 

tsitini ol Mitt |0>it) £29 91 

Cintiatdf , [J9.94 

^umpuLii C"nn £24.99 

Mmi l« Cinnn aiiij £2999 

PACMm £2999 

Sp*ct Irniin £79.99 

SUi Ranitr* £29 99 

CnBbujt A Dofeino (19 99 

Euiopim Stinit Jij iaA El 1.91 

PrtgiJinnniitij Linjoigti A Aidi 

Aiumblir (diler £3-9.99 

Attn B*tK Culiidgt £39 13 

Mat it AiitmWn | Orsfc! £S9 99 

Pi I M itimumri) £59 99 

Pilol 4Edv»1nt) Clf.1> 

Enltrlimtr Kn ;Sln Rudtrl Muni* 

ConanJind A Pan JattliC'ii £61.1$ 
Preojimntr Kit (BaiK Cumdrjl A 

Minuili) . £39.99 



43&22-3M t. f 



Commodore VIC 20 

Now ■ ttja quilily homt bujiritj.j micro far the 
priEt til t gtmni. itiehtii. 
Wk ^imoiY irptndibii lo 32KB Higr) nulaiitn (fill 
PIT ivpti e.r*fHitiH If Strttn ebIhuIi and A boidti 
Eelnuii ■ Plugi in la rum TV, er ovgiilai ■ Add Onk 
Ci..-. A Prialtrl«i iitipiiiint nW Eyti TiiUrl Car 
acE at aii mltlNgtnt tifmintl lar ■ Ilia* r canaulti, 

p129 90 




VISC0UHT SUPER X2 

64K DYNAMIC 
RAM PACK for VIC-20 

EXCLUSIVE TO SPECTRUM! 



•Jnti«ii*ii-jbl*.Dut.Uij». now yauUA up graft yt,ut 
tf(C-jatro>n iSrt Id a maillv* A?i ft*W £r.aDi»i 
fai, to load up i« 9 g*T#t or pfoorami tt ■ t-rn« ( 
id i ftjCfttl *fich afiayOu with lo uto Can r>« gitrj 
n conjunction *tth nlht* rxpamtJont ic rncr«a»a 
tocar *n*<i»ry up |o lS2K-u*iPfl 1he VIC marpofir ea;- 
pjnsiD" board. Tina SUPEH X-i mil mitt your VIC. 
JO Ihe tx Bflojl lifllf nnicrain lawn) 



Spectrum 
LOW price 



£114 



.94 

INC. 
VAT 



SPECTRUM FACTS 



Maiimum mar RAM 3,193 

T«t SEHIil 22 1 73 

High Hti;M;an 1 7S «: 1 58 

Cjiftllt Ittd .flttdf ««n fltcardu 



■rtii'.i. , .iH'i'in«>1 

Vtfr linittd tujpiiu el thi t ntn micro new aviiljolt 
- pltait eh«c« milh ftui Isttl SPf CTRUM drill' 



bilart tatkinQ a jsmrtT 

Spectrum 
LOW Price 



£345 



.00 





■ TO! RAM iiiatJltftEiri 1* 

UK) ■ BinlMn UK Bflt 

BASIC iriwjutHf ■ tt Oil 

W TFfl prcttiTdfB IS Colour 

H;gh Rnslstisn griphifi 

■ hltnuv* rtngi gf 

IP lilt Ultt loltwajrt 

ttmrnind mcau\ti *ti\ 

otli lien (junti is 

•rdHlKturiil ndi. 



Spectrum LOW Price £154 9 ' 



INC VAT 



SPECTRUM FACTS 



TEXAS PERIPHERALS- 
SlJMth. Squint ni*r 
Piiiphtial Ei p. SiHim 

One Cam. Card 

Due, Dim. 
ftAMfip, Card 



EX. 

VAT 

(40.55 
(122.00 
(I24.3B 
E23* J4 
fUSV 



Mjrr.i tni[ir . .. E34? T| 

Sahwirt Enla rta in ntnt 

Tl litatlari £1S.4t 

Ttmtilaat Cat, C19.SW 

Altael , £13.94 



(f 1 34,74 
■x. VAT) 

Mitinmn ultf RAM 14 500 Bftti UpJ""! 

TfilS^rttnl'liih Rtiilutioti 3iJj1J? 

CtiritltLaid fitm£l(l55 

INC. 
VAT 

C«.R 

11 4 30 
£142,99 
E 2 AS. It* 
DH.H 

E39S.9S 



Ell Si 
£22 9S 
£22,95 



Pi rial. 

Car Wan 

MuoiNniit 
Advititurp a Pirilf . 
Education 

Mumetr Migic 
addil len.'Sub ■[. 1 . , . 
Tuen f ouuall btgnmiri 
BASIC [,,26 

Harm BudgitMa'ijgamtnl El 91? 
. . . and minf (nan 



£!3.4i 
£«.« 

(23 43 
£31.21 

£13.13 
£31.43 



£21.91 

f 26 95 

CU.lt 
t3f.fi 

E13.9& 
EII.9& 

£9 90 

£32 95 



MORE SPECTRUM LOW PRICES 



Skivh Cnww nwnr« »*• "« id«wi iiKMMt •*■* *« < X (nmv ii Pmiti ™«»urKinrpu t, *)rsl». l uo rt tut 



A few examples from our 

Software 

SELECTION 

from independe nt software houses 

ll!Mil!IKIol 



Jurgl* 

Cbiihic Batli* 

Fiujjit 13-K.J 

Ri btnf FuncUc n i . 
Code BrtakctE. . 



(* *a 

[4 49 
£9,49 

£449 
£4 49 

Nighl Flight []K| £4 49 

RatabiLWritci 

<1&K C*»*Itt» £19 49 

BrtbH Btit (UK C«Jtit*r £14,49 

Mania '3(C) (j.49 

Ch>ii«20 |3KJ £4.49 

Slur-He f 9 45 

SDK* PhfM*l £9 49 

HIbM CmMir fS.49 

H*c.p* **-•* 

Tina Wti ,... ......tT.#l 





So llivi r< lor Atari I at , VAT 

Sutmi-'itii Ccftifliindfi ..£34.44 

JBinb* Jtl Mat £34.44 

Sweat ua.B* 

Kickback £29,34 

Han* FmiKiil 

MlMg*M*Mt ,..,,£19 49 

D4lt( CJ9.49 

Sino-iH & Billurdi f IS 49 

P«rf £10.49 

LiiLl!j!)plDD!nin3rt . £14 19 

CuBlrtt * ft Htm n f 14. It9 

MutiM H*rd . £Z4.Z5 

Scltwiri lot Com mad are 

Bit** RttEii* £25.24 

V-E Matic Ctmpdttf £ii .24 



Sell wart let Sh»ip 

r Ice ll All 33 6» . .(0.10 

CnbBjgt ri2.Qfl 

S«lt*ll* (of ZX11. 0rts«o Aihjfimif (12,08 

and Speclum lie. VM r>*n £f| $g 
Momltr Mm* it* ZXJIj. (4 41 

Wwii*( Mint (fws«*t-i'«f»i (4.?s ■■■■■■■■eefveoj 

MonUti Mint {lei Drieonj f J 99 ■111 [MM 1 I tefl 

Sptt« Hunan l,lar ZXtiJ (4,9!> IJl'J'J L'l'J H i I L" 

Sp*« Mni«iiEf« S P .C« U ™j.t4,9S T"!T!T!T^flTHAT 

Sp»ce Mnnoa llw Dragon) £7.95 **£*"* '" *""' '"■ V *J 

Dragon CH»r«l»( ficntnttf £9 95 JJ* B SliU f J „ 

■JO»VWVeOOB0Jr*#0epeV»PWH $pid"» of Man (10-99 

l^Yll 11 ll'l S*iui,i«AM»i»orn«. £15.95 

fcjj TuTllil'JHll tW. fT.90 

~^^^^^^^^^^^ lr,tfi,fi«ll £19.99 

G»m« lei Dngofi 11 Ibc. VAT Bu „ CT4 95 

Urninin Tin .... £9.95 T.nk Attack £18.95 

IHltiittv £7. IS WorSCratt 

V»hm0t+. £7 95 WordProealM", pictage (125 BO 

Ci*«t*moiin),u-ini f/ 04 

Cult UM 

Plus many more at 
your local 

SailnirtlorCaraniooW CDCi-TDl lr.4 

vic2Q i«.v*t SPECTRUM 

SpKt St<wa.., £6.49 , ,, , 

ski nun £*49 dealer — call In 

Dm* Baggy...,,,, £4,49 . 

supjr Whi £4.41 now and see! 

SANYO Colour Monitor 

CDD3125N 

ONLY 

£228.85 .nc vat 

(E199.0O »i- VAT) 

SANTO lie. VAT Sj<iglipart1f*x9j~prift(»f 

SAMTOirgrwnasmtoi. iSO.Sfl ?*atr. osx ol MM6 iliieti (13. OS 

Sim 30 CtiUtld Rtcordti £19.95 VJC-iaAcc«ut)iittfroni Viscannt 

CTP3I31 U'Caloor TV 3*1 (129.99 Molh»rbo»rd viiMdoi B«rr*r.(24.9S 

CI I CuMtl*! (0 . .40 Vc [h* ibt-ji (J *,■!*! if u1l t r ( 23 .90 

Siflflt n d«d. ti nil* deitptr 1 KK RAM Part , , £43 ,95 

niik* (1.99 JltFUMFieJt CMJf 

OeuM* i i i , 4 d o u ej I * M K H A M Pack f 11 4 .94 

4**4itf ttiiki (3.30 Curlih ChalEtifaaaVsict 

O.iklvtadtltiiirr £T04« SmlAtfiacr £07.44 



RABBIT 





Now available from Spectrum Computer Centres- 

the top selling- 

SINCLAIR ZX-SPECTRUM 




Yea, t-hJS lop selling micro is now available from 
your local SPECTRUM COMPUTER CENTER ir> bottl 
1AK and 49K RAM. So now Ihere's no need to send 
by Tiaii order, just call inio your local SPECTRUM 
dealer and pick one up. But just one word of warnjtig, 
wilh i his added avail ability advanlage slocks am 
bound to sell fast - so make It soon! 

SINCLAIR ZX SPECTRUM 16K - £125,00 
SINCLAIR IX SPECTRUM 4SH - £175,00 

Spftclrurn Computer Canlres have no conned ion whatso- 
ever wilh [he £X-Spe-ctru!T> Computer niariufAciur-pd try 
Sinclair Rese*rcti Ltd. 



SINCLAIR ZX-81 



SINCLAIR ZX . . 
16K RAM pack 

ZX Printer « . 

Co-iripuler Boeik&haii IUC- 

3allwi»fDr Sinclair VAT 

Com outers 

B-jmoii 1 IK fMl ,. .CS.tS 

". K, SutXil ll:« JKSl ct.es 

LttwmthlCKlXm . £b.9b 

rtigMnu m P»ik ,'Mu« c 1 BK IXS1 , 1 6.95 
Conpulacjlc IS* 7iH1 CT.fH 

Pc*lHjr>i» B*nlir*a S>T-tC-m 

teKzxei rii.M 

Sdjc* lnvjd*n/ft*u:u* 

iakzic^i r« M 

aieihaut tOK 1X«I CB-SS 

MMBif DKlJtei £S.t6 

f-ail rvi is c 'e-K 2x41 f t 'j*j 

f«0lEMll Mctio»r l-JK 7XS1 . . C7 » 

Cast *n«* for ZXtl Tyi»— iu 

& G»n*r» £j,44 



C491.95 
. £29.935 
. £59.95 

Junior Ed'j£jlini» . X3.W 

Out in*4i b r(oui*hol(J £3.91 
Skill ii juiicjcmini Cinm C3.M 

Jui4j tduc«i>on. . . C3 •* 

FlWlh Qui.- . CS »i 
Tip* M 

Fanojn Bww . . f- 4 75 

iB*i 4 ft*IO*rt Ir BdmlMrt. C4.7B 

Tvim— » 

Sup»< FiOsi'amtNst. 1 -0. f4,H 

lyp* — 40 

Biekaammun t'S.95 

ip.urnSunuljrijn Cb.lS 

"tvp*— M 

Englnh Lilti*tni« 1 CSSf 

Iflol.ih Ulaiiluia ? £ 6.91 

GcOfl Ufi4)y E6.9i 

Hulqrv 1 Ce.SO 

MalAl. 1 £6,44 




Give your ZXS1 the 
power of a big micro! 

CHEETAH 64K 

RAM PACK 

ONLY £54.95 



Quality PRINTERS at super LOW prices from Spectrum 



EPSON 




KB 

INC. 

Model VAT 

HXU-T1 ......OTO.M 

Hl«0f T T r p* III £414.39 

MXlOOTrpflil [439 15 

Pltlil lag >r>nr SPECTRUM St alt I toi 
pi ice 1 at I NTFHFAC E,' CABLl opliens. 



SEIK0SHA 




BMMA 

Hin a rap qujlitt giapfai priaUr 41 i bck« 

f au tin jflerd. CearrtXlLtt iRltlliC* Ur.mdi 
tiulf wuh mm eiicur. 

5p*elru<n LOW pn«* f 219 94 Int VAT 
Cabltt It Inltrt aras > villi hla fn r mail miLrej 



SMITH CORONA 




Ms no TIM 

MiciopiOMSiSt c4AIidII*4. tiigh cjuiIiIt 

dli4H nhttl pnaitr at a LOW c*H <i»ro 

SPECTRUM. Sarul, Parallal w IEEE 

IntfrliM, 

Spaclrvn LOW piicr £|ST.75 tic. 

VAT 




BOOKS 



SE LE CTION f HO M T H E C Mf U f t* t r>* /i S pltir u n tncj h«* Is gat 

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More memory for vour ZX81! 

ZXPANDA. 

The uniquely expandable 16K RAM pack 

The professionally produced 16K RAM Pack 
that is expandable to 32K simply by 
plugging- in our expansion module. 
Start with 16K . . expand later to 32K! 
Solidly built attractive ly cased to fit 
perfectly on to a 2X81 without wobblal 
Includes LED power indicator. 
The RAM pack that won't become 
redundant when you want more than I6K 

16 K Expandable RAM E32.95 

16K Expansion Module £19.95 

More sound from your ZX Spec trum! 

Echo 

Not only more sound, but better sound and a wide range of 

other facilities! 

Control Volume, and adjust tone of sound! 

Load and Save without switching leads! 

Audible cue facility for tape programs! 

DIN compatibility! 

No additional power supply needed \ 

Attractively cased- looks good 

-SOUNDS GOOD! 

Only £23.50 





More m emor y for y our Jupiter Ace 



Pacer 

The uniquely expandable 

I6K RAM pack 

Similar concept to ZXPANDA but tor 

the incredible Jupiter Ace. 
Attractive, solidly built 16K RAM pack 
with the facility of expanding to 32 K 
by plug-in module. 
For more power to faster FORTH . . . 
you need a PACER! 

16K Expandable RAM £29.95 

16K Expansion Module. .... £19.95 

18 YOUFl COMPUTE. iPftii 1363 






More memory for your VIC- 2 

VlXen RAM Cartridge for the VIC-20 

Switchable between 16K or 8K + 3K, 

Gives you the option of full 16 K RAM or SK and 3K RAM m one 

package, When added to a Standard VIC 20 

gives 16384 bytes of extra memory in 

memory blocks I and 2 or 

3092 bytes of extra memory 

into the 3K memory block AND 

8192 bytes of extra memory 

switchable between memory 

blocks 1 and 3, 

Fully compatible with available motherboards/ modules. 

Simply plugs into the rear expansion port of computer. 

No re-add ressmg of existing BASIC programs needed. Only £44.95 

Tandem 

Expandable Expansion System for the VIC-20 
Gives 4 expansion slots for VIC-20 cartridges. 
Custom-designed case. Plugs directly into 
computer. Further expanded 
by using TANDEM System! 
ROM socket for expansion. 
No extra power supply needed 
Only £34.95 



I Aid 




Ston«hip Electronics, Unit 9, Ths Brook InduHiul Eiiitt, Dttdbiufc Lint, 

Aldershot, Hints. lelcfhont: (0252) 316260. 
Please foivrjid me the tollomnji products: 



All price m idctusirt of VAT, P«l i P«km| lor U.K. deliveries [oversew jdd 15%| 

Name . ,,...., ,»....... 

Address: : .... i. .................. 



STONECHIP 
ELECTRONICS 

"more ways to make more of 

Lyour computer" J 

^■1 ^M MH I^H ^H ^H ■■ ^B ^^H ^^H 

DEALER ENQUIRIES WELCOME Deliver y appro* Wdays 





Cruising 
on Broadway 

Behind the wheel of your 
machine. Cruising on 
Broadway. You look mean. 
People stop to stare. Suddenly 
a black-and-white pulls onto 
the Broadway behind— its light 
flashing and siren wailing. The chase 
isonJ 

Cruising on Broadway is a tyre- 
burning fast machine-code game for 
the 16 & 4SK Spectrum. The further 
you can gel the more dlfficuJt it 
becomes— cash prizes are being 
offered each month for {he highest 
scores. 
£4*95* 




2 cassettes 



TheWorking Spectrum 

4(228 page book) 
irst well -documented 

collection of serious programs 



i*i* iL.TK*^^rJ ■L-M.ll' JlMtfl* ■tl-Illi 



include a Basic Renumber 

which can handle Gotos and 

losubs. a character dictionary, 

a file-handler, several utility 

programs and a few games. 

Each program is built up out of 

re usable subroutines. 



' Submit if our program to Sunshine 
And your name could be here next month. 



Blind Alley 

A deadly duel. deep In space. 

Blind Alley is what passes for 

sport in the year 3017. Your era 

must use strategy to out-wit and corral 

the opponent— in this crazy development of the pursuit games of the iate 2600s, 

After each round in the enclosure game more players are sent against you to test 

your sill and agility. Blind Alley is the machine&de action of the future— now! 

For I he 1 6 & 48K Spect rum. \ 



THE WORKING 

SPECTRUM 



TheWorking 

Dragon 32 



O— tL— ■» «,« 




IWlDlWfitNCI 




'Available thi*pjr»W H Sfrn!h'.sand computer oeaie^s 
Please send me 



^2 

SUNSHINE 



TheWorking D 

This is a companion volume to 
The Working Spectrum and 
includes several new features 
such as a Text Editor and a 
Music Composer and Editor. 

tther programs help you use 
e Dragon 32 as an 
accountant, for more 
advanced high resolution 
graphics, as a home tutor for 
education and for playing 
games. Each of the programs 
and subroutines is explained 
line byline to help develop 
your own programming skills. 

£5.95* 



Tr»tfe*M iwi MiianriWweittfT-S 



□ 
□ 



The Working 
Spectrum 

at £5 95 eacn 

The Working 
Dragon 32 
ai £5.95 each 



Cruising 
on Broadway 

ai £4,95 each 

Blind 
Alley 
ai£X95each 



Name 



Address, 



I enclose a cheque/ oo$W order tor E 

payatfeto Sunshine Books 

T9 Wniicomb Street. London WC2 7HF. 



Signed , 



L--_ 



We can normally deliver in tour lo live days, 



J 












/ 



The assault on your 
senses has begun J 
with a great , \^ 
choice of games \ 
that have been > 
created to give ^ 
you a real 
challenge! 



-'.-"■ 






••the name 
of the game 






m 



tt&tev 



.-/J .- 













b 




TT 



A 















••the name 
of the game 



4° „* 















^vyw 1 



"* sfJ i^ JC* .t t 






Any of these games for just 

£C50 

41W+ EACH 




including first class post, 
packing, VAT and an 
UNCONDITIONAL 
LIFETIME GUARANTEE 



When you buy imagine Software you buy it for life. If on 
Imagine Software product EVER foils 1o load first time 
simply return it to Imagine for on injtgnt free replacement. 
All orders despatched by first class post within 
24 hours of receipt* Subject to stock availability. 
Why not put o first class sEamp on your envelope and you wi 
receive your order within 3 days of posting. Available from 
W.H, Smiths, Boots, Laskysand all good software outlets. 



Dealership enquiries contact: Mark Butler 



Imagine Software, Masons Buildings, Exchange Street East, Liverpo 



«*>^ 















>w>* */>> 4°^V 



.■#■> 






/> 



I, Mereeyside L2 3PN. 



^V^ 



cp^p 




Post coupon now 'Q Imagine Software, Mgjonj Building*, 
■ Exchange Street East, Liverpool, Merseyiide L2 3PN, 



Weose ruah ma- copies f>l I tick bt>x| 



■ □ Arcadia □ Schizoid* 
OAhDfddums 



D Arcadia Q Wocty Waiter* 
DCoichoSnalcho 
O Motor Maul D Frarclic 

■ (lor gny ZX Spec Mum) [i©r any Commodore VlC-20) 

■ Pfease debit my Access/Bardaytord (delete as necessary! 
"Cofd 
| Number 



I 1 endose Chequa/PO lor £ . 
_ Nome 

I 



Address. 



VC3I 




SUPERFAST CREDIT CAftDSALESUNE: piwwji. 

051 236 6849 (24hrs) " 




THIS IS THE A6E OF 




HOME COMPUTING 




ZX Spectrum 

SOFTWARE 



GORF IAN 

GORFIAN INVADERS, A Superb 4 screen 
machine code program with Invaders, 

Galaxians, Firebird and Flagship. 
Multicoloured Hi Resolution graphics and 

Sound Effects. 

For the 40K Spectrum, price £5,00 

KRAZY 
KONG 

KRAZY KONG, Another 100% machine 
code program, featuring 3 Screens of Hi- 
Res Gorilla, Barrels, Fireballs, Lifts and a 
Running and Jumping man who must 
rescue his girlfriend from thr* enraged 
KONG! For the Spectrum, price £5.00 

SPECMAN 





#* #*# ********* 



** ******* ***** 





mm& mm® 



F ROGGER ^ 



FROGGER AND SPECMAN, two excellent games for the price of one! 

SPECMAN is probably the best version of it's type with great machine 

code graphics and sound effecis wiih 3 to 5 ghosts, power pills and a 

real munchie man who munches Sway '" a" directions unlike cheaper 

versions! 

Frogger, is a 2 screen superb representation of this arcade classic and 

has full colour Hi-fles Frogs, Cars, Roads. Logs, Turtles end Rtverbank. 

Plus Super sound effects. 

Both on one cassette for the Spectrum, price £5.00. 



CENTIPEDE 

CENTIPEDE AND PAINTER 

By the time you read this our latest release for the 

Spectrum should be available 

Centipede is a full colour machine code arcade game 
where the object is to defend yourself with your Laser 
against a f&st mowing gentipede whigh weeves in end 
out of the mushroom patch. There are other versions 
Of this game but we think you'll prefer ourb because 
we always Strive for an extra dimension of realism, 
which makes ail the difference! 
Painter, is another welt loved Arcade game here you 
must paint in between the numbers on a 
multicoloured screen before you have to overlap, 
Price for SPECTRUM is E5.O0, 



HOW AND WHERE TO GET C Tech Software PRODUCTS 

There are three ways to get the tape that you require, firstly you can go to one of 

around fifty retailers in the UK and some more overseas, there is at least one in every 

town and several in major cities. 

Secondly you can ring our Telesales on 061-366 8223 and Atison or Shirley will take 

your order and tell you of any other games you might be interested in. 

Last the most popular way is to simply clip the coupon and send it to us at: 

C Tech, 164 Market St r HYDE. CHESHIRE, SK14 1EX. 



flWSE SEMJMf THE F0UOW>SG 



*n MAW A«(i AdOMSS 6 



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A computer simulation of the popular electronic "One 
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Enjoy hours of entertainment with this hangman type game 
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PROGRAMS 

for the 
DRAGON 



MONSTER MINT, by W E. MaeGowan. 

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alien fleer in deep io«e. Multiple skill levelt a::d The best (f ap.hict ever . . , .£7.9$. 

GOLF by Pete Allen. 

Over 20K of Sax, givinf sou full IB hale §o!f coufve with handicap! eho4ec of clubs, 

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Landing by Peter Chase. I la Hitman by CtUittOpher Hunt, Speed boll by Prter Chase, 

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Revtisi by pr. H, J. Ftytr. 

Tty 14 treat tlsr Dtagon it this fmcinaititti board game, From Noviw 10 Grand Master, 

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Play thii ftvouMic card jame utth the Dragon U the. banket, Incredible tfajihics ahd 

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ALIEN HI IT/ by Peter Chase. 

Youi cult is running !i>» on Fuel and you mun land I You hast to uie your oombi to 

deai a space arnontjst the sky>craperv, but beware of srjicis' A superb mul1i-locl action 

gamr, with super h louftd .1 rid ^-raphiimi ..,.,.»,.. £ J? 9 H; 

GEMPACX IV by VY. E. MaeGowan. 

Two great machine code games with full colour iraph:ci. In Sea Hnrner you muH land 
on the K.uvr*li iifritr iflef dilpetslAi (he cloud*. In Sub ChiSc you must depth charge 
the wolf pack iMthou: being }unk. Both with * l«v«b of llcrll from eaty 10 

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Create and use your osnt tjtntol* and character teii en the Onsen's hiih resolution 

graphits icfccns Writttn in Bat it for tut of us#, Comrs nMt complete ASCII character 

file and demonstration program , .,.,.,. £9,95 

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Three great Educational Qui* games. Bet on (he ajMweit of your ehoktMid; bt a ssinntf !' 

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YOUR COMPUTER, APRIL 19S3 27 



YOUR LETTERS^ 



THE CASTLE OF RIDDLES 

yfi Last the task is finished — Castle ol' Riddles is solved! 
^J Although it undoubtedly took me longer than many others, I 
posted my compeiitn.ni form earlier this, morning, I also felt the 
nced to make a few communis, 

f am not an adventure game cjipert by any means, Castle of 
Riddles was the first I have ever completed, but what a marvellous 
five days* enjoyment I have had. A thoroughly well-planned and 
written program with only one exception which 1 will come to in a 
moment. 

I would never have believed the incredible emotional ups and 
downs a game like that could produce-, I'rom Saturday morning to 
evening, passing the Shooting Gallery or the Awesome Creature 
was proving absolutely impossible. That was a low low. My wife 
encouraged me to lake a break and relax. A few hours later the 
rhought or exploding the case and scaring the Giants seemed a 
possibility. Sure enough that was. a high. Later in bed, amid a 
turmoil of thoughtSj the association between the red paint and the 
creature occurred. 

On Sunday morning with trembling fingers, I threw the can of 
paint and observed with undisguised joy the dying of the beast. 
Thai was a high high. 

The one odd thing about the program was the Black Rod. I jm\ 
tould not believe that losing the rod before moving through the 
Black Passage was correct, t tried for a long time making the trip 
from the Pit through the tunnel the final move, but that of course 
proved impossible. 

All hough the ruthi answer h achieved by not carrying the rod 
through the passages, surely there must be a way of retrieving it 
first? I would very much like to know. 

However, congratulations to Your Computer and Acomsolt for 
mounting a brilliant exercise, I sincerely hope that it will not be 
the last. 

P Craft, County Down, Intend. 



SCROLL TRICK 

Jk feature lacking oil the Sinclair 
ffSpcctmm is the Scroll 
command. Although substitutions 
have been published for this, 
involving Poking and Priming, 1 
believe that my solution is much 
neater. Simply, place the line, LET 
A ■ L'SR 3280 in your program, and 
the entire screen will be scrolled up 
by one line. 

Peter Bermtem, 
Northwood, 



POLYGON BUG 

rhL Sinclair Spectrum has a 
versatile bug in the one-liner 

PLOT *,y DRAW 3,b, n*Pt 

There ii a pentagon at 
s-y-a-b^SO, n- 100.5. Odd- 
sided polygons arc usually larger 
than I he circle whose diameter is 
defined by the line joining x,y and 
K + a, y+b. Thus they go off the 
screen, with an Integer Out of Ratine 
message. Good examples are the 
near-perfect triangle spooking about 
al s-220, y-210, i-b-50, 
n m 168,24, and the heptagon lurking 
somewhere bciwcccrt it "71.5 and 

ra.5. 

The bug trawls in at rt D 17 and is 
cyclic. As odd values of n go up, the 
circle turns into an apparently 
rotating polygon. As in rises, ihe 
number of sides decrease and ihc 
speed of rotation increases, program 
running time s:ays constant at eight 
or nine seconds. 



At some point it collapses into a 
rotating line. I think most of these 
collapsed polygons arc at non> 
integer values of n. As n increases 
further the polygon "opens out'" and 
the number of sides increases, The 
cycle then repeats. For polygons and 
stars, the trick is to find values of n 
thai visually "locks" the rotation 
and gives a static shape. 

[ recommend trying siitatl rallies 
for a and b in studying the odd-aided 
polygons, so that they stay on-screen 
even if I hey are very large relative to 
the circle diameter 1 cannon my 
Spectrum recently went into ter- 
minal coma and is back at Chateau 
Sinclair for a rebate! 

John Brtisier, 

Stanford in the Valr t 

Oxfordshire. 



LYNX FAN 

■ Jour review of the Lynx in your 
JT February issue prompts me to 
reply to some of Bill Be mien's 
comments: He op^ns hi* review with 
I he assumption thai the consumer 
wants gimmicks or a computer with 
some outstanding feature. Any 
prospective Lynx buyer should bear 
in mind that some machines with 
outstanding features have thenai the 
expense of some graphics. If anyone 
wants gimmicks, I suggest that they 
compare the Spectrum dead-flesh 
keyboard with thll oi rite 1 ,ynx 

As a ZX-SI owner I know that 
Sinclair's manual provides one 
chapter of two pages on machine- 



code. The Lynx manual's machine- 
code chapter es nine pages long. I do 
not think any purchasers can expect 
a great deal more. 

Your reviewer seemed to he dis- 
appointed by the Beep command — 
perhaps he is jaded after all the 
machines he has reviewed. Anyone 
wishing to try out Beep need only 
walk into a branch of Laskys and 
tvpc in tile following dittv: 
90 RANDOM 
100 LET W-RANOI2Q0) 
110 t.ETC~RANDf200) 
120 BEEP W.C.63 
130 IF W C THEN LET W-W'Z 
140 IF W = C THEN GOTO 90 
ISO GOTO 100 

Our 15-month-old daughter thinks 
that this beats Beethoven, 

I agree that the manual could be 
improved by the addition of an index 
— I am sure it will be. 

Why was there no mention of the 
Lynx's ability to accept abbreviated 
commands? For example. Auto to A. 
Also, why na mention of single key 
entries? I think rhat indeed the Lynx 
dkK-n indeed offer something new — 
ii is consistently good. It is soundly 
engineered and it does not overheat. 
It has a well-designed, professional 
quality keyboard, and it is British 
and available. 

No doubt by now you have 
guessed that previously 1 had been 
using a ZX-81 and now am the 
proud owner of a Lynx. Before 
buying it I looked at the BBC 
machines. You have Id pay another 
£195 to implement CP/M on the 
HHC I personally did not like the 
Dragon as it was not Z-80 based. 
Following my bad experiences with 
mail order from Sinclair, imagine the 
trepidation with which 1 ordered my 
Lyns on November 22, I9J32. 1 had 
hoped to receive it before Christmas 
hut did anticipate some delay with a 
brand new machine, Imagine my 



surprise when I received a letter of 
apology in the New year apologising 
for the delay and promising it by 
mid-January. Sure enough it arrived 
on January 20, Considering the 
Christmas holiday 1 do not think 
thai is a bad record. 

I wanted CP/M because I had used 
WordStar at work and appreciated 
what a vast range or software would 
be available tt> me given that disc- 
operating system. 

R D Miigher, Worthing, 
Wett Suntx. 



NO STRINGS 

Ajfi lisccll seems to think BBC 
/Yj Basic is more standard than 
Sinclair Basic because BBC Basic 
supports string arrays — Letters, 
January issue, p27, In fact, those 
funny MidS, l.eftS, RighiS and 
similar commands are an aberration 
of Microsoft-type Basics, and not 
"standard" at all. 

The proposed American National 
Standards Institute — ANSI — com- 
mittee X3J2 is currently finalising 
Standard Basic. It does not include 
siring arrays, and it does make Let 
mandatory. The original co-author 
of Dartmouth Basic, and Chairman 
of the ANSI committee, noted last 
year that string arrays had gone and 
cried "Good riddance!" 1 agree. 

Anything that can be done with 
string arrays can be done with long 
strings, but not vice versa> Also, 
siring arrays are not a feature, in the 
Microsoft form, of any more ad- 
vanced language I can think of. If 
you want to progress from Basic, it is 
not a good idea to come to depend on 
them. 

Mind you, I would rather use BBC 
Basic than Sinclair Basic. BBC Basic 
is good, but look al the size of it! A 
better Basic ts the Cromcmco Struc- 



DUTCH DRAGON BOOSTER 

f JJith reference to Stephen Mummery's letter — February 1983 
TY — regarding the increase of the Dragon 32's user-available 
memory, I can add that with the following statement: 

POKE25.6:POKE27,6: 

POKE29.6;P0KE3l,6 
you have 31015 bytes at your disposal. You have also cleared the 
first high-resolution page, which could not be done with ihc 
PCIcar statement. With ClcarO you can add another 200 bytes. 

Another useful feature, which you can achieve by changing 
pointers, is to Merge programs. First you have to Chml the first 
program. Then you ask the contents of memory locations 25,26,27 
and 28 with the command: 

?PEEK(25), PEEK (261. 

PEEK(271,PE£K<28) 
Mcxt you have to Poke the value of location 27 in location 25 and 
the value of location 28 minus 2 in location 26 — suppose the value 
is 1 37, then you have to Poke value 135 in location 26. If the value 
of location 28 is or I then you have to subtract one from the 
value to Poke in location 25 and the value to poke in location 26 
would be 254 or 255. Mow you can Cloud the second program. 
Make sure that all ihe line numbers are greater than those in the 
first program. That can be done by the Retmm command. The last 
thing to do is to Poke the original values back to location 25 and 
26, which will be in most cases 30 and L If you enter the List 
command you see you have both programs together. 

T A Bik, Amsteheetty Netherlands, 



29 VOUfl COMPUTER. A Will 1983 




lined Basic, which also lack* suing 
a r rays, but Thai's 32K. We should alt 
have so much spare memory, 

I own in Atari 800. Atari Basic is a 
Mrippcd-down version of ihr Cro- 
memoo Basic, written by the same 
people. It takes up only about 8K, 
and has long sitings instead of string 
arrays. As it is supplied on a plug-in 
ROM, however, you can remove it 
and load an enhanced Microsoft 
Basic — that is more than twice the 
sot — from disc without running 
Out of memory. Alter natively there is 
in enhanced version of Atari Basic 
called Bask A*, available from 
Optimized Systems Software, Again 
it was written by the people who 
wrote Atari Basic, is upward- 
compiuble, and includes the things 
that had to be left out of The SK 
ROM such as Print Using, While — 
Endwhile, and If— Else — End if. 

The moral is simple. The most 
powerful feature to look for in a 
Bask is that you can remove it, or 
switch it out, freeing the address 
space cither for another Bask or 
another language. 

Jack Schofittd 
Lendon W3 



SPECTRUM TIPS 

##ere arc a tew tips for increasing 
ff execution speed when writing 
programs in Basic on the Spectrum. 
A program's memory may be divided 
into three parts: the top, The middle 
and the bonom, each one being more 
appropriate for rhe storage of a 
specific functional pan of the 
program. 

The top part, which always has 
the lowest line numbers, is suitable 
for frequent ly-used loops and 
subroutines — the most-used ones 
have the lowest line numbers- It is 
useful to make a subroutine with any 
frequently-used loop — having taken 
all unnecessary computations out of 
the loop — and then put it at the top 
of the program's memory. It is still 
better to pack each subroutine 
within one line only, keeping in 
mind however that For-Mcxi loops 
are better at the beginning of a line 
instead of in the middle, The middle 
part is used to store the main body of 
the program. 

The bottom part is convenient for 
functions that are performed only- 
one time per execution, like 
initialising variables, dimensioning 
arrays, reading Data statements and 
so on. It it better to declare vari- 
able* beginning with those most 
frequently- referenced first. 

The reason for all that is that 
jumps are always performed by 
processing through line numbers, 

Starting at line 1, and skipping over 

to the next line until match is found; 

thus, The fewer lines away from line 

1 you are, the quicker the jump. Do 

not forget that this gain is multiplied 

by the number of jumps performed: 

in French, we say: "Les petite 

ruisseaux font les grandes rivieres"! 

Andri Dideler, 

GtHeta, 

Switstrla nd. I 



EDITORIAL 



After thje ravages oJ glue sniffing and teenage 
alcoholism, the nation's youth are now 7 in the grip of 
computer addiction. Recent shock reports tell hnw 
children sneak back after four o'clock to use then- 
school's computer laboratories, or meet in derelict 
buildings to program pocket calculators. Parents 
are warned of the tell-tale signs: (he inability to 
converse in anything but machine code; the 
complexion horribly coarsened by hours at the 
keyboard; the eyes vacant except for the cursor 
flashing in the corner. 

Clearly all this make* for good, scarermongering 
newspaper stories which are, of course, totally 
misinformed. Every computer fan, knows thai you 
are just as likely to observe this kind of behaviour in 
adults as in children. A recent survey by Gowling 
revealed that the father and son partnership makes 
up SO percent of home computer owners. Micros 
arc bought for sons by fathers who believe that 
understanding computing will help their child in 
school. Presumably as soon as the micro arrives at 
home some children become users very quickly. In 
ether cases, the father feels he has to get to know 
the machine if he is to help his son — and becomes 
hooked in the process. So, what seems to 
distinguish this addiction from other vices is that 
parents and children are equally responsible for 
introducing each other to it. But what is it about 
computers that makes them so habit-forming? 

Some will claim it is the dement of problem- 
solving involved in programming. Others will 
answer that it is the fact that micros promise 
mastery of a finite and logical universe contained in 
a small plastic box. A place where — unlike the real 
world — if you have the knowledge, what you want 
to happen surprisingly often does. In other words a 



kind of hi-tech escapism. Others, still under the 
influence of a dose of Space Invaders, will be 
unable to answer at all . 

In the old days lecturers complained that all-night 
drinking and debauchery disrupted students' 
studies. Now a new villain has emerged. Tutors at 
London University claim that many under- 
graduates are spending five hours a night 
intoxicating themselves with the pleasures of home 
computing. Students arrive for their lectures lit 
only for another game of Pae-Man. 

So much for the vices but what about the virtues 
of computer addiction? A physical dependence on 
micros could make you highly productive — if only 
in terms of computing. Jobs that can only be 
regarded as chores by the ordinary owner are fun 
for the addicts, who see in even' new operating 
system the chance of a kind of electronic nature 
ramble. 

The computer-dependent form an unpaid army 
of software engineers ready to engage themselves in 
any national programming cause that appears on 
their screens. It is exactly because there is this level 
of obsessional commitment to home computing that 
such a profusion of software exists in the U.K. 

Kids have been addicted to arcade games for 30 
years. But whereas the teenage pinball wizards of 
the past only profited the pier managers today's 
silicon whizz-kids are learning skills which could 
stand them in good stead for their future careers. 
Some already have careers, programming for the 
big software houses. 

And although critics view the addiction as 
dangerous, the bank managers of the child prodigies 
may well be content to sec them continue living 
dangerously. 



How to write for Your Computer 

We called this magazine Your Computer precisely because we welcome your 
views, tips and hints and even your criticism of machines and software in general- 
It you would like to see your name in print, whether on a Software File program or 
a full-blooded article, here is how to go about it. Ideally, all articles should be 
typed double spaced on one side only of uniform sheets of paper. If listings can 
be dumped directly from a printer you can always use a friend's or user group's 
this minimises the risk of error. In a perfect world a cassette would 
accompany the article. That considerably speeds up the checking process. Mot 
only do you get to air your own discoveries and opinions, but we will even pay 
you for the privilege. We pay f 35 per published page - that's as It appears in the 

magazine and includes illustrations. 
Why not give it a try? You have nothing to lose but your postage. 



ABC 



Editor 

TOBY WOLPE 

Assistant Editor 
MEIRION JONES 

Staff Writer 
SIMON 8EESLEY 

Staff Writer 
SIMON BEESLEY 

Sub- editor 
PAUL BOND 

Editorial Secretary 
LYNN COWLING 

Editorial: 01-661 3144 
Your Computer, Quadrant House, The 
Quadrant, Sutton, Surrey SM2 5 AS. 
Subscriptions: U.K. £8 for 12 issues. 

Prinud In GflMl Srtwlr) lor th» frop.-ister* of 
Buttret* Prtm |n(JWTUiJen«l Ud. QuJdrent Houw. The 
OuMJnni. Sutton, Surrey SMS SAS. T*l: 31-B$1 35M 
Ttdwyimi- BEO&s BSPRESG. (SSN 0283-CS8S, 
Primed By flivtnfd* PrMa Lid, Wtvt»1it*r, Ktnt. jrri 
typ***i bv Imhp Ltd, London ECi 



Advertisement Manager 
PHILIP K1RBY 01-661 3127 

Assistant Advertisement Manager 
PETER RICE 01-661 8441 

Advertisement Executive 
BILL ARDLEY 01-661 8484 
NIGEL BORRELL 01-661 3127 

Midlands Office 

KEITH SALT 021-356 4638 

Northern Office 

RON SOUTHALL 061-872 8861 

Advertisement Secretary 

JEANETTE MACKRELL 

Classified 

CLAIRE NOTLEY 01-661 3036 

Publishing Director 
CHRIS HIPWELL 

Business Press International Ltd 1383 



YOUR COMPUTER APRIL 1963 29 



NEWS 



Happy birthday Microdrive — and now a big 
hand for the ZX-83, ZX-84 and Microvision 



You will be able 10 order the 
Microdrive on or about April 23 — 
the anniversary of its official 
announcement. Sinclair also ha* A 
ZX-83 in store for us this year, but 
the revolutionary all-in-one com- 
puter exclusively revealed in last 
November's Your C#**>pu:tr h now 
dubbed the ZX-84 and may not be 
released until nest year, 

Sinclair's Song awaited Microdrive 
is a compromise between cassette 
storage and floppy-disc storage, A 
high Speed tape loop — or stringy 
floppy — will store over 100K of 
data or programs. Sinclair is 
confident that the access time will be 
less than the 3.5*. advertised. 

The £40 prices is less, than 
originally expected but a £10 drive 
controller containing an RS-232 
interface is necessary to connect the 
Microdrive io a Spectrum. 

Initially Microdrives will not be 
able to run on any other computers, 
although one controller will allow 
you to run up to 40 Microdrives off 
one Spectrum. 

The Microdrives will accept inter- 
changeable tape-loop cassettes. 
Initially Sinclair will sell games and 
adaptation? of existing Spectrum 



mm 


TOD **rt 


1 Ur 

Garnfi Company 


Mnchinn 


■ Arcadia Imagine 


Spectrum 


■Chop Creaiiu« 


VIe-20 


liter Software 




■ Defender Atari 


Atari 


■ Dragon Sataman- 


Dragon 


Tnsfc der 




■Flight Psion 


ZXB1 


Simulation 




■Football Addictive 


ZK-31 


Manager Games 




■ Gorf COnwnp 


Vlc-20 


dor* 




■ Tru! Melbourne SjWctrtim 


HobbH House 




■ Hungry Psion 


Spectrum 


Korsoa 




■ Intro to Commo 


VJc-20 


Programnri'dora 




Ing 




■ King Kong T D 


ZX-B1 


Sofnwe 




■Miner Big 5 


Atari 


2D4Ser Softwaro 




■Monatefs Acomaoft 


BBC 


■ Pimanifl Automata 


Dragon 


■ Planet M .nrofirji.il 


Dragon 


Invasion 




■ Piffnetoidis AeomsoH 


sec 


■ Rocket Acomsoft 


BBC 


Raid 




■3D J K Grave 


2X81 


■3D Tunnot Wow 




Spectrum 


GerHfatbr 




■Tlmegaw Qutckaha 


Spectrum 




Software on these cassettes. Blank 
cassettes will be made available to 
other software manufacturers. 

Priority will be given to satisfying 
the Microdrive orders of these who 



ordered Spect runts last summer, so 
it could be late this summer before 
the microdrive goes on general 
release. 
Sinclair's Microvision tlai-screcn J 



pocket television should be launched 
this July, opening the way for the 
9in. fiat-screen to be incorporated in 
the ZX-84, which will also have twin 
Microdrives and a Modem. 

Nigel Searle, Sinclair Research's 
Managing Director is playing bis 
cards close to the ZX-83, but he has 
confirmed rhat there will be one — 
"It is fairly natural iryou follow the 
sequence; ZX-8Q, ZX-&L, Spectrum 
- alias ?X-82 T ". 

Yqmt Computer spies have 
observed several projects which 
could be the ZX-83 under wraps at 
Sinclair's new Cambridge 
headquarters. One of the favourites 
is a Spectrum with improved sound 
capabilities and a Modem which 
could be rushed into production if 
rhe Oric begins w threaten Sinclair's 
hold on the market. 

The situation is further confused 
by the low-cost desktop business 
computer which Sinclair has de- 
veloped for ICL to launch this year. 



The difference between an Apple 
and a Peanut is just £300 



'l !ii u't'u n ..-.st: I'.fiT^ i-'fiim mid 
April Peanut Computers will be 
selling an Apple look-alike with 
virtually the same specifications at 
fusi over half rhe price. 

Like the MFF-1I, another Apple 
copy, the Peanut is imported from 
the Par F^st. It is designed to run 
Apple soflwate and to take many of 
the Urge range of Apple II 
accessories. These include RAM 
I'xpansion boards, Z-80 interface 1© 
■I m the computer to run CPfM 
Software* language Curds and an 
flO-colurin display card. 

The standard machine comes with 
48K RAM and is expected to sell for 
arnund £M5, Two graphic modes 
are offered, pi vine 3 resolution in 
black and white of 280 by 192 and 
colour resolution of 140 by 192. The 




The Appfe If £ — Apple's latest attempt to stave off Apple ft copies. 

text format provides 40 columns by 
48 rows. ]f will be sold by mail order 
from Peanut Computers, Unit 20, 
Low Mill, Dewsbury, West 
Yorkshire. 



Just propping up the hack of you/ home micro cart save it from 
overheating end certainty makes it easier to Type on. While most 
compuferniks lean their slices of 1980s high technology on cassette 
cases, door wedges or state sandwiches, Hi Stak plastic tegs are the latest 
spring fashion. Wftrp factor Sight sells them at an appropriately 
astronomical £3.95 for n*p- ff you use something really obscure to prop 
up your micro, write in and teff us and we will send you a pair of Hi S(ak$. 




Check your 
power packs 



SlKCl air research has been obliged 
to recall some 28,000 power packs 
after discovering that they could be 
dangerous. 

The power packs are recognisable 
by a white stripe on the power 
supply's output to rhe Spectrum. 

What makes them unsafe is that 
the 240V input track inside the 
power supply is too close to the GV 
output — it is possible that a power- 
spike during very humid weather 
could result in a user receiving an 
electric shock. 

Sinclair Research Managing 
Director Nigel Searle admitted that 
the power packs — just one batch 
from one supplier — were not 
checked in detail for safety. 



30 VOUR COMPUTER, APWL 1983 



NEWS 



\ 



BBC Micros 
for the blind 

A GRANT worth £18,000 from the 
Department of Industry will help 
i he Open University to open up 
microcomputing to ihe blind and 
p;ir i tally- sighted. Eight schools will 
be supplied with "touch and hear" 
systems based on BBC Micros 
equipped with speech synthesisers, 

The system reads line* of Basic 
aloud as they are entered usmt a 
Votrax-bwd Type and Talk syn- 
thesiser instead of displaying them 
on the screen. So instead of, say: 

TO PRINT CHR*1231 
appearing on the tube you would 
hear 

TEN PRINT CHARACTER 
TWENTY THREE 

Many blind people can net use a 
conventional typewriter keyboard 
but are fa miliar with a manual 
Braille typewriter, the Perkins 
Brailkr, So Dr Thomas Vincent and 
his Manchester Open University 
team which has been developing ihr 
system over the last year has adapted 
the Perkins machine is an altern- 
ative keyboard for the BBC Micro 
hy fitting mkroswirches to sense key 
depression and an interface to the 
BBC Micro. 

Vincent hopes that the micros will 
step the blind children from being 
left behind as computer ski IK 
become more widespread. It should 
also make it easier and more 
enjoyable to learn Braille. 

Double Dragon 
the 64,000 byte 

Watch out Commodore and BBC, 
Dragon Data plans to launch a new 
64K RAM machine late this 
summer. The £180 Dragon 32 which 
has now sold 35,000 units wi3 1 not be 
discontinued when the £300 64K 
machine goes into production. 

Commodore at least will be well 
able to drop the price of the 




Versatile n 
Texas com 

The struggle to win a place in the 
nation's briefcase becomes even 
more heated with the launch of the 
Compact Computer 40, the first in a 
Kliej of Texas Instrument* portable 
computers, Texas dearly intends it 
to compete with the Epson HX-20. 
I ike the Epson computer it has an 
liquid crystal display , a QWERTY 
keyboard and a numeric keypad. 
The display has 31 characters, can 

will answer 
question 

Commodore 64 if the competiiioU 
gets too hot. A spokesman refused to 
deny persistent nimours that new- 
technology makes the £350 64 
cheaper to produce than the old 
i 1 30 Vic- 20 and would only say thai 
price was "all to do with what the 
market will bear — not to do with 
what it costs to make". 



ew portable from 
pletes the Tl family 



be scrolled left and right and 
adjusted for different contrasts 

Measuring 9in by 6in, by I in, the 
CC-40 weights 22oz. and takes four 
AA alkaline batteries which provide 
power for up to 200 hours. Programs 
arc retained in memory when the 
machine is switched off. 

Memory capacity is 6K of RAM 
expandable to I8K, and 34K ROM. 
Plug-in cartridges can expand the 
ROM by a further 128K. The Basic 
is compatible with the TI Basic used 
in the T1-99/4A and the new 7149/2 
announced last month. 

The CC-40 will also take the same 
low-cost peripherals as the TI- 
99/4 A. These include a £150 four- 
colour printer and the £120 
Wafertape digital tape drive which 
takes 40R tape cartridges and has a 
data-iransfcr rate of 8,000 bits per 
second - 

A RS-232 interface will also be 
available and at later dsie Texas will 



Cut-price rail tickets offer for 
first Midland Computer Fair 



Whisper it softly but Acorn's 
Electron may receive its first public 



showing at the Midland Computer 
Fair — and combined rail fare and 



Acorn's Electron should be out by the end of April 




idmisMOH IKke'.S will CU( ihe CO*l of 

getting there. 

Tens of thousands of home com- 
puter enthusiasts are expected to 
turn up tp the Fair al Bingley Hall 
Birmingham which will be open 
from 10am to 6pm on Thursday and 
Friday April 28 and 29, and 1 0am 
until "5pm, Saturday April 30. 

Admission will be £2 — half price 
Tor children and pensioners — but 
British Rail and IPC Exhibitions are 
offering cut-price all-in fares; such as 
£12 from any station in London, 
£9.50 from Manchester, £4 from 
Coventry and £4.50 from Hereford. 



release other peripherals such as a 
Modem, a bar<odc reader and a TV 
interface. 

The CC-40 is expected to sell for 
around £110, Texas claims that It 
has more capabilities than the Epson 
portable computer and thai it will be 
considerably cheaper — even with 
the additional cost of the printer and 
tape drive. 

Not some new videogame 
monster but s face which may be 
fust PS frightening for sums' of 
the big names in micro games, ft 
belongs to Richard Branson who 
msfite mfffions from Virgin records 
gnd is now turning his evil eye to 
homg computers- Nick Alexander 
win tun Virgin Games which wit! 
bring record-company style 
razzmatazz to computer games. 
Nick Alexander reckons that 
computer games will soon 
become even more popular than 
video films. 




VOkJH COMPUTER. APRIL 1 983 31 






fiiO©CD©(I)®QQ(SO 




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G 





G 




B 




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•SPACIOUS SHOWROOM 

OPEN MOW. to SAT. 
♦FRIENDLY AND HELPFUL STAFF 
•EXPERT ASSISTANCE 

ALWAYS ON HAND 

*GOOD RANGE OF COMPUTER BOOKS 
•AFTER SALES TECHNICAL 

BACK UP and SUPPORT 



a®& MICRO 

Model A432K} 
MocWB 

Marjory Upgrade 

Full Upgrade 

JoysHcks ipairt 

Single Disk D'rvo 

Oiik Interface ITilledl 

14 inch CotOUrMOnilor 

20 inch Cotour Monitor 

ACORNSOFT PROGRAMS (phone for av*il$toiHtyj 

ACORN ATOM 

Singly Dj«fc Drive Unci. FREE buMor kit) 

ATOMCALC ROM 

WORK PROCESSOR ROM 

FLOATINGPOINT ROM 

ROM S€iec(-o* Board 

BBC BASIC Board 

Prog rammt* "8 TOOLBOX 

SUPERTQOLBOX 

M/ C CO DE MO WITOR / DTS ASS EMB LEfl 

PRINTERS 

EPSON MX80F/T III 

EPSON MX8QT HI 

STARDPB4S0 

SEIKOSHA6P1COA 

Printer Leads (BBC/ATOM- DRAGON l 

BOOKS 

A&serrbly Language Programming for the BBC Micro 

SBC Mlcfo- Instant Machina Code 

BBC Mice RivtiibH 

BaiieProgrimmingon furBBC Mico 

Le>l Your B BC Micro Teach You to Ft ograrn 

NEC 30 Hour BASIC" 

practical Progrtmiforthe BBC Microend Acorn Atom 

Setting Acquainted with your Acorn Atom 

39 Teai«J Pre® rams tor th* Acorn A torn 

A torn Magic Book 



C32SQQ 

C34»00 

£399 00 

C25 00 

rre.oo 

£1300 
f 265 00 
£113 00 
£309.00 
£34385 



£39.10 

fjggrj 

£23 00 
£22 40 
C4S.9S 
£20.10 
£16.00 
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£399 00 
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E22900 
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DRAGON 3 

THE FAMIL Y COMPUTER TO FIRE 
YOUR IMAGINATION 

KEY FEATURES 

* "32K RAM as Standard, Expandable to 64K 
••Display: 

9 colours available, 

5 different resolutions from 16 x 32 

to 256 x 192. 
** Extended MICROSOFT Colour Basic 

as Standard. 

Advanced graphics commands. 

Advanced Sound 

Full Editing— insert, delete, amend. 
*• Professional Typewriter Keyboard 
••FREE 160 page 'BASIC training manual 
••Connections for Joysticks, Printer, 

Cartridges and Cassette. 

PRICE ONLv£199.50ir«I.V.A.T. 

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32 YOUft COMPUTER. APRIL 1983 




£3,000 Riddle 
— the winners 

Now it CAN be loid — the names of 
the winners of the F«tr Computer 
and Acornsofr Curie of Riddles 
competition. Peter Vokt from 
Aylesbury, Buckinghamshire was 
the first to deliver the right answer, 
m person, 

Second was C P Bignell of 
I.mlchampwi, Wbi Sussex and, in 
third place, P K Colbert of Heath, 
Cardiff, Nessi month, we will 
publish fuller details for those of you 
still stuck in the Pit or over-awed by 
the Awesome Creature, 

Down with the 
Atari 400 

Atari rs LAUNCHING! rhree-pmngisd 
attack on, micro users. Prices of the 
400 scries home computers Save 
been slashed by £40 to £160 for the 

hare loK RAM machine or £200 if 
you warn Basic and the manuals. 
Meanwhile ihc £400 Atari 800 has 
been upgraded from 16K to 48K 
RAM without a price increase and a 
conversion kit will soon be available 
to turn the Atari video parries 
machine into a home computer 



NEWS 

Maestro and Renault II pop 
talking micros under the bonnet 



At last motor manufacturers are 
waking up to the possibilities of on- 
board microcomputers. Computers 
have been creeping into luxury cars 
like BMWs for the last couple of 
years but only with the announce- 
ment of the Renault 1 1 and the 
Austin Maestro last month has the 
micro appeared in volume pro- 
duction. 

The Austin and Renault systems 
are a similar use ro the aver age home 
computer with the addition or a 
voice synthesis unit which again is 
similar to some of the plug-in 
peripherals available for home 
computers, The Maesrro's unit is 
based around a 6805 microprocessor 
running at 4MHz, 32K ROM is 
used to store 15 phrases such as 
"Fasten your s?at bell 1 " including 

Austin's Maestro - below — and 




warnings of high engine teirrpcrature 
or low fuel, 

In Britain the voice is female but a 
further 1 2SK ROM on export 
models incorporates German, 
French and Italian voices. The 
French have also opted for a female 

the Renault ft — above. 









km ft — . — - m -- 

km. fna — — 






*Qk 



Computer 
fix micros 

HlGH STREET computer garages 
where you can take in an ailing 
micro and have it fixed on the spot 



Now you can plug your Spectrum straight into a professional printer 
ustng the new Euroetactronks ZX {.print Centronics interface. This 
partiiiet interface wilt free Spectrum owners from dependence On SintiSir 
peripftcrafs arid wiit be tough competition for Sinclair's serial RS-232 
interface which should be launched this month, Both the ZX Lptint and 
Sirtrfmr's RS 232 should cost around £30, 




garages to 
on the spot 

for a fixed Fee of £10 are the latest 
ides from Liverpool software house 
Imagine. 

Sending your home computer back 
to the manufacture]: after it gives up 
the ghost in the middle of a game of 
Pac-Man can be a frustrating 
business. With horror stories of 
people waiting up to a year for 
repaired machines to be returned, 
Itnigjne's Mark Butler is confident 
of the demand for a simple High 
Street repair service. 

The first computer garages will 
appear in Liverpool bui Mark Butler 
is already negotiating with an 
Oxford Street store and hopes to set 
up branches all over The country. 
The garages will deal with 
Spectrums, ZXSIs, BBC Micros, 
Dragons, Vic-20& and Atoms. 

Previously Imagine was better 
known for games like Wacky Waiters 
and Ah Diddums but although 
Butler claims that 70 per cent of 
Spectrum owners now have 
Imagine"* Arcadia, ii has not starred 
in Yemr Computer's retail Top 30 
because most of the sales have been 
bv mail order. 



voice but the Germans and Italians 
will be warned by male voices. The 
Germans will be confronted by a 
barking "Achtung, achtunpf, every 
time they step out of line. 

Renault has opted for a similar 
voice unit on ihe Renault 1 1 — a 
fast back version of (be top-selling 
Renault 9, A Female voice will regale 
the driver with advice while a male 
voice will -shout warnings. 

The Maestro's voice unit will only 
be available on the top of the line 
Varuten Ptas and MG models but the 
microcomputer will control speed 
and temperature sensors on all 
models and will power a digital 
display board. Smiths Industries 
who makes the unit claims that the 
vacuum Eluoresccnt display of speed 
and fuel consumption is 20 times 
brighter than » television screen. 

Bob Dickens of RD Labs has had 

to head for the hills because of 

Your Computer. Safes of the 

Digital Tracer — a device which 

allows you to copy drawings 

straight to the screen with o 

Spectrum or ZX-8T — have 

proved so successful since we 

reviewed it in January that RD 

labs has bad to move to a new 

factory in Cwmbran, South 

Wales. 




YOUR COMPUTER. APftrL 1983 33 



^^ ■■ A\ I VI ■ I ^^ I ll ^^ n CARNELL SOFTWARE 




X 





WIN A FABULOUS 'WINGS' 
HOLIDAY FOR 2 TO FLORIDA. 

VISIT THE AMAZING NEW 
EPCOT CENTRE 

Volcanic Dungeon, the addictive adventure. People have 
been kno w n 10 ven tu re i n t o i ts maze of caverns to rescue t he 
Princess Edora again and again. If you are one of them, or 
wish to be, then you could find yourself lying on a sun 
drenched beach in Miami for a week. Followed by a 
further week at Orlando, visiting Disney World and 
Epcot. So what do you have to do for all this? Just be the 
best Volcanic Dungeon player in the U K, that's alt! Ten 
finalists will hattle it out in the championship at the London 
Computer Fair. Eart's Court, in June 1963. But first you 
must prove you are worthy. 

Volcanic Dungeon is avaifable^n theJ£K ZX-81, 48 K 
Spectrum and Oregon 32 An entry form is supplied with 
every game. {Anyone who already own: gfnal £X 

Version can enter by sending a SAE for wjnJ 

Order youf copy NOW from CARNELL SOFTWARE, 4 
Staunton Road, Slough, Berks. Only £5 00 including 
P£rP. Also available from good microcomputer stores. 

~he 'Judges' decision is final and no correspondence will he 
entered into. Ail business associates of Carneil Software, 
and their relatives, ate disqualified from entry. A copy of the 
rules of the Volcanic Dungeon championship will be 
supplied with the entry form. 



/ mfi 



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*V 








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GET THE BEST NEW PROGRAMS AND THE 
ALL-TIME GREATS, SPECTRUM OR ZX81 

AT SOFTWARE SUPERMARKET NOW 



We siatted Software Supermarket with just one idea To play all the 
Spectrum and ZXSl games we could find, to select the very best and 
to offer only those to our customers. 

Judging hy our mail irom all over the world, you're very pleased 
with our fiee selection service It's impartial (we produce no programs 
ourselves) and it saves you CtXson stamps and mistakes. 

And it 5 fast We usually despatch your order within 48 hours, 
Here s the best of the new and the best of them all for yam Spectrum. 
Plus some great ZX81 games, Full detailed catalogue sent free with 
every order Or send large SAE for catalogue only 



ZX SPECTRUM; 16/48K 



Oui la.es [ Top 10 Programs for youi Spectrum The' 



;n both 16 Si 43K 



An ff IKf MCf 3iJbant NEW 3D giaphw game by Malcolm 
Oii 1 UIvIvuIj 'Escape" Evans Fry down the winding 3D 

tunnel shooting bats spiders, nogs and iais' Demo mode 3 speeds: training 
program fo: each phase. And (4SK only! watch ow foi the Tarje nam 1 
(New Generation) £5 95 

*%n mAuy NEW game with stunning graphics Shoot die 
JU 1 AIM A enemy from your 3D tank turret 3 play levels accurate 
ballistics: j o! 2 players hold feature demo mode naming program And 
choose your own control keys even plays 'God Save The Queen' i 
(DKTieoics) C4 3& 

MTIIuriPn A IffMnrD "One of the best, vowrs 
W1JN \XEmU A V EiH \JE*M\ all the stages of lite Arcade 
original, .a game to coins back to ' PopVomp Wkly Veiy lasr PHOENIX 
7 play levels: 3 attack waves laser shield mothership with smart bombs, [Work 
force) £4 50 (16K ZXfll version iA 50) 

fan /"if turn AirfiA t*V ^ ss * ®x&nan w?ftfran of 
KxtXXjXJiMlJ All AV/A the arcade game' YrOxsp 
'Very absorbing" E&C "Extremely good Pop:Comp , Wkly Thrilling 
SCRAMBLE" Pilot your ship thro 26 rones up. down brake thrust' smart 
bombs: as you get better, it gets harder iSitversolt] £5 .95 

r^VKfTTDITTlir '^* *' ,sl an( " ast ' Spectrum version of 
vull llrLUlli the famous ai cade g;i::.f full arcade 
movement ■ left light up. down, tire - as you attack the centipede. Great 
graphics Watch out hi the jumping spider* 3 lives hold feature. 
(DKTronics}£4 95 

r+Cf* A 111! 1 ^ e olIiie test and most anginal games we have 
add \*f Air £i seen S User b vary real dinosaurs chase you ton:::: I 
maze as you search lot the axe to escape. Different maze every time 5 play 
levels' 9 speeds Hall of Fame {New Generation) £4.95 

p|t| I)mf A W "^ oris csssei [if ! - 3{ 1 wwtid buy <i.o 
\J vJ La Jr IV1 *7T N ?xt >-ptHmai program " Pop Camp Wkly \ 5 ma/ts , 
each with demo mode 9 speeds laser gun helps against 4 chasers. Program 
your own aanlid. keys personalise/save your vary own game (Campbell? £5.95 

f*£\%*flMf\C ■ hJEW) F ara astic Sophies Loads in 2 pans 

vwdulvu (instruction manual first) Protect your 9 ships against 
16 aliens, warp mines, asteroids Your graphic en-board computer helps with 
elaborate displays. Our favoumenew game (AbbaxJ £5.95 

1? AFICP'C POT f V The hi st acventuie we've seen 

CAUul Off vIIjuX that's worth playing in 16K It's great 

and it's got graphics 1 Loads m two parts cleai instructions fus*. Then a 

smashing adventure with directions'. Inventory, look, score, save Aiu^zuigi 

Abbex) £5 95 

nTIITI f f\ Recommended without reserve .a superb 

KJ 1 £l£ilill V opponent' Yr Camp The great 19th Century power 

game Su iit-und your opponent capture his territory Millions of different 

games: maximum 60 moves eacii. 1 or I players demo game: 9 skill levels 

crint (Moll £7 95 



L 



JflfrlW lW 



Special 16K ZXSl versions of G of theie programs are available: 



WIKGED AVENGER £4.50 
OTHELLO £6,95 

BLACK CRYSTAL £7.50 



PEMAN1A £3.00 

CHESS 2 £9.95 

GREAT BRITAIN LTD £4.95 



48K SPECTRUM ONLY 



These programs use nearly all the Spectrum's 49K They will not run on the 16K 

Specbum But there are versions of Black Crystal GB Ltd Fimania and 

SpecChessfcrfo:16KZXe- 

w% T« jr ji RT Y A T?> e best adventure game we have reviewed ' 

JT 1IV1AH1A S.Ikes 'An adventure enthusiast's dream" C&V 

Games Best use of Spectrum graphics and music we've seen A wonderfully 

witty adventure and yoi; could win die £6,000 GoJden Sundial of Pi 

(Automata) £10 {ZX81 1SK version £8) 

ft TfUTE 1 [* A *nij* ~^ e txst graphical game 1 haveseen on any 

1 lIHJLvlA 1 Ei micro' Interface 'Excellent graphics one of 
the best " Yr Camp. 'Fast and furious , required playing for any Spectrum 
owner* Which Mas? 5 skill tevels uauiing program HoW HaU of Fame, 
keyboard oveilay 25-page on-screen manual. (Quicksilva) £&,95 
mtip UADDTT 'Superior to any other adventure g&me 

1 JtUl tlKjDDL 1 available for the Spectrum" Yf -Camp 
Free 285 -page illustrated book of The Hocbtt contains clues to heip solve the 
adventure 'JO neautifiU f ult-scteen pictures 500 word vocabulary: 16 page 
instruction manual save: punt pause. It took 4 people 18 months to write 1 
Melbourne House} £14.95 

GREAT BRITAIN LTD'iSSSS' 

management game Pets Comp 'wld' "Difficult and challenging ' ZX Comp 

n plays 'Rule Britannia' ' Choose your party and run the country, Will inflation 
and unemployment come down or the rioters come out? It's up to you. Then 
watch the results on election night 1 (Hesseil) £5 95 ( *5K ZX81 version, £4.95) 

*}mr J!il#l*Xll!ii9i9 sirrJiTgessr chess ptpgt&ai' Pop Comprlvkty 

Full graphic chessmen ' 7 play levels ■ all legal moves' positron analysis !or 
problem solving recommended move option print game history (A.'Uc)£S45 
;ZX81 [jon- graphic 16K version £9.S&) 

nf a/117 PDVCTAT Take the adventure of your Ufe 
Dli Al/A VrA 191 All 1B0K of piogiam to unravel, on 
two thiillmy cassena^i You must solve each of the 6 stages to defeat the 
Lords of Chaos Real-time monster battles: If command keys. (Caineli) C7.5C 
[16K 2X81 version Oer 10QKiradsin7pans.C7.50} 

Foci Itn SOrTWAAE SUVLHHAflKET. 17 Howudi Liu, London , SW1S6NU, 

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Use the coupon to order. Free detailed catalogue of Oar best 

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YOUR COMPUTER, APRIL 1983 35 



LOAD AND GO WITH YOUR DRAGON 



tt PROGRAMS FOR YOUR OR AGON tt 

* Games Pairs 

Pontoon 

Snakes and Ladders 
Ski Run 
Gastk Walls 

* Homework helpers 

Sums Tester 
Vocabulary tester 

* Graphics section 

Full explanation of all Graphics 
commands with worked examples 
+ Hints and Tips 

* How to debug programs 




Depi A FREEPOST EM46J (No stamp required) 
99 East Si. Epsom, Surrey KTI7 I BR. 
Telephone 03727-21215. 24hr phone service. 
Prices include postage but for air mail delivery in Europe add 90p (outside Europe add £1.70} per item. 

Access and Bmclaycard accepted 



PHIPPS ASSOCIATES 




THE SPECTRUM POCKET BOOK 



loOpp *% f ^g\ Trevor Toms, best selling author of the ZX81 Pocket Book and the Sinclair 

■frffc ll f ^ arrl i n E Lab, turns his attention to the ZX Spectrum — the book you have been 
&*^J*+S*J waiting for! All the materia! in the book is totally new. 

Programs Hints & Tips 

• Castle walls; boiling oil and lovely slurping Discover new ways of using PRINT; INSTR functions, 
noises VAL, PRINT USING, hexadecimal conversion, upper 

• Great Fire or London; try and change the case conversion, load and save arrays. BEEP with sliding 

p l- mrv tones, automatic scroll and how to use all the machine 

course oi nisiory features within machine code. 

• Chase: outwit the pursuing robots and lead _ _ . . ^ , 

them to their doom ^^ hiI1 ? C ° de „ , „ h * A „ „ ■ 

t _ , . . „ ^ ,««, a «.,-,-»!* All the toots you need to write machine code ettectiveiy. 

• Truly amazing; generate a new maze puzzle Graphics loo f kLl ._ debug monitor _ symbo i assem bler 

every go (with labels, all ED commands, ORG statements, forward 

• Reversi; the classic oriental strategy game and relative jumps) — disassembler (with label asstgn- 
with board screen display meni); now you can really dig into the Sinclair ROM! 

• 3D Maze; race against time and three T hh sectk>n alone would be stupendous value for money! 
dimensions to escape. Cassettes Spectrum games as opposite £5.00 

r Spectrum machine code as above £5.00 

Also Available ZXS1 Pocket Book I38pp £5.95 far ZX81 Nowttnik Puwle, DemolHion & Tcnpin £5.00 

ZX80 Pocket Book lttpp £4.95 _ . 3 ^ventures: Greedy Gulch 

Aiom Business HOpp £7.50 *™*\ „ A<r ™agic Mountain Pharaohs r ° mb g'°° 

KK include VAT ZX81 Pocket Book Cassette £5.00 

TkT-B"«"rfcTfcn a nn/\/^T A mnri De P l A FREEPOST EM463 (No stamp required) 

PHIPPS ASSOCI Al Eb », E *< ha^faSE IBR - • 

Telephone 03727-21215. 24hr phone service. «■ 

Prices include postage bui for air mail delivery in Europe add 90p (outside Europe add 12.20) per item. m ^ mm 

Access mid Barcknvard accepted 



38 VOUfi CO^PUTFR APRIL 1 983 



COMPUTER CLUB 



Computer Club is here to encourage you to start your own local computer club or, if one already 
exists, to join it and become involved. We would like to hear of anything which has made your 
club a success, or of any projects or programs you are developing. 



Camden 
keys in at 

Queen's 
Crescent 

Meirion Jones takes a look 
at what's happening down 
in North London at the 
burgeoning new club 
based at Queen's Crescent 
library in Camden. 

While anna ford, David Frost and the rest 
of TV-am's megastars were launching them- 
selves from Camden Lock on to the nation's 
breakfast tables with a "Hello, good morning 
and welcome" 1 a quieter bur perhaps more 
effective launch was being prepared down the 
road at Queen's Crescent library. 

It fill started with a chance enquiry by Wil 
Jackson ai his local library. Why, he wanted to 
know, did they have so few books about new 
technology? "You would be surprised how 
many people who come in here have their own 
computers," he told Branch Librarian Jean 
Walton. She made him her computer books 
adviser, and by February there were 50 
computer titles on the shelves and it was time 
to set up a computer club. Camden Council 




gave free use of the library where the club has 
met every Tuesday at 7pm since. 

The club concentrates its efforts on new- 
comers to computing with two beginners* 
groups and a more advanced programming 
section. Many of the 30 members who attend 
each week are still at school. 

When we visited, one group was huddled 
around a Spectrum in the hands of Simon 
Warren — a radio engineer. They had 
mastered the essentials or Basic and he was 
showing them how to debug a program — in 
this case an error-prone version of Mini. 



Local society news 



Amateurs in Spennymoor 

SPENNYMOOR AMATEUR Computer Club in 
Country Durham meets every Thursday 
evening at the Spennymoor Recreation 
Centre. Members own a wide range of home 
computers, and new members plus their 
micros are always welcome. More details from 
Anthony Vincent on 0388-8 17304. 

Stevenage Sinclairs 

A computer club for owners of Sinclair 
machines has been formed in Stevenage. It 
meets on the first Wednesday of each month at 
the Stevenage Library. Telephone John 
Fearce on 0438-50587 or Bill Googe on 
0436-54758 for details. 

South Trafford computes 

South trafford Microcomputer club meets 
once every two weeks and puts out a monthly 
newsletter which contains courses in Basic and 
machine code. The club is open to all serious 
users with an interest in learning pr 
exchanging ideas. For further details write to 



Ian White ai 16 Leicester Avenue, Timperley, 
Altrincham, WA15 6AR or phone him on 
061-969 2080. 

Yate and Sodbury 

YATE AND SODBURY Computer Club formed 
only recently but 80 people attended its 
second meeting. The club meets on the third 
Monday of the month in the canteen at 
Newmans, Station Road, Yate. You can 
telephone the secretary, Kay Crowe, on 
0454-517461. 

Brentwood buffs 

Meetings of the Brentwood Microcomputer 
Club are held every two months on the third 
Monday of the month at the Methodist Hall, 
Warley Hill. The next meeting is on May 16, 
starting at 7.15pm. The club regularly 
organises talks and demonstrations. Future 
meetings will include a visit from a 
Commodore representative and a talk on 
network programming. Contact Allan Holland 
on 0277-22 1&20 for further information, 



Simon showed how to trace problems in a 
program but the final error proved elusive and 
so the group learnt an unexpected lesson — 
knowing when to give up. 

Wil Jackson, who is now the chairman, was 
explaining the rudiments of computing to 
newcomers using another Spectrum. In 
another corner Lucas Fowler the club 
secretary was demonstrating a ZX-81 input/ 
output board which he had made for an 
O-level electronics project. 

Robert Martin — a professional programs 
analyst — was explaining structures to the 
more advanced programmers and advocating 
flowcharts. He also warned against becoming 
so obsessed with the program that you forget 
what you want it to do. "If you proceed from 
the output you cannot go wrong. If you find a 
bit of the program interesting and start there 
you can lose sight of the overall objective — 
and end up with spaghetti programming." 

The club is increasing its links with other 
groups. While we were there a missionary 
from Worcester Park preached the benefits of 
Joining the Association of London Computer 
Clubs. 

Camden Council is hoping the Queen's 
Crescent project will be a success so it can be 
spread to other libraries in the area. Wil 
Jackson hopes the effect will be "like ripples 
on a pond. From Kentish Town to Primrose 
Hill — and from there you never know where 
we will get to." 

You can find out more about Queen's 
Crescent Computer Club by catling in at [he 
library or ringing /can Walton on 01-48: 
4551, ■ 



VOUR COMPUTER, A PfilU 1963 37 



FIRST 8YTCS 



Starting out in home computing? First Bytes is for you, 
Just write to Your Computer with any hardware or 
software problems, no matter how small or simple. 

QUESTIONS 

What are the arrows? 

'Tell me more about the cursor control keys. 
How are they used to control movement?* 



LURKING SOMEWHERE on every computer 
keyboard are the four cursor control 01 arrow 
keys which are of particular importance in 
editing programs, and other text, and it} 
com rolling on-screen movement in games. 

When you are entering program lines you 
will find that the left arrow — backspace — 
often acts as a delete key and will erase the last 
character which you typed. If your particular 
implementation of Basic has only a line editor 
then only the left and right arrows are ofust 10 
move back and forth along a single line, but if 
you are fortunate enough to have a full-screen 
editor then the up and down arrows will also 
move you from lint to lint. 

Often the cursor symbols are not displayablc 
on the screen and must be dealt with as their 
ASCII character codes which are as follows: 





shift not 


shift 






pressed 


pre&»«d 




li''i arrow 


3 


21 




right arrow 


9 


93 




up arrow 


94 


95 




down arrow 


10 


91 




Organising movement around the screen must 


lake into account 


how the screen is maj 


>ped. 


The following i 


'ouiine sorts 


out the 


four 


movements, in both upper and lower case 


for a 


screen addressed 


as X, Y coordinates, 




10 X = 0, Y = 









20 AS INKEVSlIF AS -- 

A ASClAS) 



THEM 20 ELSE 



I could 
do that... 

Most microcomputers only store 
integers to eight or nine-figure accuracy. 
We will award £15 to the shortest 
program which multiplies two 12- dig it 
numbers and gives the answer to 
24-digit accuracy. Entries must be in by 
the last dey in April. Contestants had no 
trouble in answering March's 
programming challenge. The winning 
program was sent in by D Waring, 
Staddie Stones, Stock Green, Redditch. 
His solution is simplicity itself: 

10 INPUT AS 

20 LETAS = " "+A$ + " " 
30 FOR N = 0-20 
40 FORM = 0-31 
50 PRINT AT N, M; A$ 
60 NEXTM : NEXTN 
70 FOR M= 20-0 STEP 1 
80 FOR M = 31-0 STEP-1 
90 PRINT AT N, M; AS 
100 NEXT M: NEXT N 



30 IF A ^ BORA =21 THEN X-X- 1 

40 IF A = 9 0RA = 93THENX = X + 1 

SO IF A-94 0R A-95THEN Y = Y-1 

60 IF A =10 OR A = 91 THEN Y-Y + 1 

90 GOTO 20 

If you want to ensure that movement does not 

exceed particular boundaries add: 

70 IF X<XM THEN X - XM ELSE IF X>XS 

THEN X = XS 
B0 IF Y<YM THEN Y ~ YM ELSE IF Y>YS 

THEN Y = YS 
where XM = minimum value and XS the 
maximum value of X, and YM = minimum 
value and Yis the maximum value of Y. 

Where the screen is mapped sequentially — 
Matting from the top left and returning to the 
left at the start of each new line — the 
appropriate lines for modifying the prim 
position (P) are: 

30 .. P-P-1 

10 P = P + 1 

50 P = P-LL 

60 ..... P = P + LL 

where LI. is the number of characters a line. 

BEATING 

STOP 

Debugging a program can be both 
frustrating and enjoyable. Some people seem 
to have a gift for homing in at once on the 
source of a problem. Obviously the more 
experience you have the more likely you arc to 
develop an intuition for the son of bugs that 
cause particular types of error. 

But most of us have to adopt a rather more 
systematic approach and there are several 
straightforward techniques that can be 
usefully adopted. 

Beginners are often unaware that although a 
program has crashed, Us variables still hold 
numbers and characters. To find out the value 



CHARACTERS PRINT 




One OF THE FJRS'I Basic commands everyone 
learns is Print which puts characters onto the 
screen. In its simplest form: 

10 PRINT "HELLO" 
The message Hello will apear at the left side of 
the screen arid the print position will then 
move to the oext line below, so that if 20 Print 
"Rrst Bytes 1 ' is added the screen display will 
be; 

HELLO 

FIRST BYTERS 

Punctuation is very important in controlling 
print position as can be seen by placing a 
comma ai the end of line 10, which changes 
the display to: 

HELLO FIRST BYTERS 

as a comma only moves the next print position 
some way to the right and not onto the next 
line. 
If the comma is now replaced by a semi- 



colon the new print position i$ directlv behind 
the old one giving HELLOFf RST BYTERS 
which is not very helpful. To stop the two 
strings running together place ft Space at the 
end of the first one to give 

"HELLO ". 
Note that spaces are often automatically left 
either side of numeric variables to keep things 
tidy without effort. 

When you want to put material in columns a 
Tab — for tabulator — command is useful, 
This moves the print position to a particular 
column of the display on the current line and 
is most useful for tables. Note the careful 
punciuaiion which stops your carefully-chosen 
print position jumping straight to the next 
line. 

10 PRINT "DATE" 
20 INPUT DAS 
30 PRINT TAB 16): DAS 



40 PRINT TAB(15>;"CREDIT" 

SO INPUT CR$ 

60 PRINT TAB[24J;CRS 

Even more exact control of print position is 

available through Prim @ — or Print At — 

commands which specify not only the column 

but also the line of the display, allowing you to 

jump easily to any point on the screen. 

Their exact operation depends on the dialect 
of Basic and the way the screen display is 
mapped, Screen mapping is usually one of two 
types. In the first the print positions ate 
numbered consecutively From the top left 
hand corner, jumping back to the left hand 
side of the screen at the start of each new line. 

In the second, print positions are defined on 
an X,Y grid. Thus 

PRINT AT 10,10; "HERE" 
on a ZX-S1 and 

PRINT @ 330, "HERE' 



38 YOUR COMPUTER, APRIL 1983 



FIRST BYTES 




FHEBUGS 



\ND TRACE 



of the variables simply type as a direct 
command 

PRINT A,B,C 
or whatever variables you want to look at. You 
can then work out what values they should 
have at that stage in the program, and set 
about finding the point at which they have 
been corrupted. 

Programs that run but do not do what you 
want them to are even more worrying. The 
problem may occur because the program is not 
following the path you intend it to. It may be 
branching to the wrong subroutine or perhaps 
pay not be returning to the right place. 



D 



R 



LY 



on a Dragon both Print 10 lines down and 10 
columns across. 

For really fancy printing the Print Using 
facility^ which allows you to specify the print 
formal, is invaluable. The structure of this is 
Print Using format — image of print structure 
requited; output list — what you want u> print 
— and the most common use of this option is 
in printing columns of cash in a form where 
only two decimal places are displayed and all 
decimal points are aligned. 
10 INPUT C$ 

20 PRINT USING '**#>* ";CS 
30 GOTO 10 

If the following values are input, 123.456: 
987.54: 6.4; 4.3211 this is the display: 

123.46 
987.54 

6.40 

4.32 



Whatever the cause, the first step here is to 
track down the point at which things arc going 
wrong. A good procedure is to insert Stop 
commands at different stages of the program 
and check whether the program runs correctly 
up to those points. In this way you can 
eliminate the sections that appear to be 
working properly and narrow down the 
trouble spot to a single routine. 

One of the most useful debugging aids is a 
Trace facility. This is built into BBC Basic 
but some toolkit packages, such as 
Commodore's Programmers Aid, supply it for 
other machines. 

Trace gives a printout of the line number of 
each progiam line before it is executed, A 
proper Trace facility should also allow you to 
control the speed at which the program is 
executed and should print the line numbers in 
a window in one pan of the screen. If these 
features are not present — as they arc not on 
the BBC Trace — then the line numbers come 
too fast to follow and overwrite the rest of the 
display, 

if you do not have a Trace facility you can 
write a simple version yourself: insert a print 
statement in the routine you want to check 
telling the computer to print the variables or 
line number at the top of the screen. 

These techniques will not help you if the 
screen goes haywire or blank and the 
computer does not respond when you press 
the escape or break keys. 

Almost certainly, in this case, the program 
has either Poked the wrong location or 
contains a machine code routine which it 
cannot break out of program. The only 
solution is to turn the computer off and start 
again, right from the very beginning. 



Decisions, 
decisions: 
branching 
programs 

MOST COMPUTER PROGRAMS involve 
decisions and have branches in their structure. 
Although it may appear that the computer has 
a mind of its own you must always remember 
that it is only carrying out your instruct ions to 
the letter. The simplest type of branch 
involves testing a variable against another 
variable — or perhaps an absolute value — and 
taking some particular action in consequence. 
The general form is If condition is true 
Then take action, for example: 

■ 10 IF A- B THEN GOTO 100 

■ 10 IF A=B THEN B = B + 1 

■ 10 IF A - 10 THEN STOP 

The Full form of this type of conditional 
branch is If condition is true, Then take action 
I, Else take action 2, although the latter part is 
often omitted as, if the first parr is untrue, the 
program will fall through to the next line 
anyway, Let us consider a situation often 
found at the start of a program! 
10 PRINT "DO YOU WANT 

INSTRUCTIONS? lY/Nf' 
20 INPUT OS 
30 IF QS^"Y" THEN 1000 

40 rest of program 

7000 ..., .instructions 

As you presumably want to ret urn to the main 
part of the program after reading the 
instructions Then Gosub 1000 may be better 
than Then 1000. The test as it stands is OK. as 
long as some clown does not reply with Yes 
instead of just Y, but if we change 30 to: 
30 IF G$ = "Y" THEN 1000 ELSE IF 

QSO"N" THEN 20 
then only V and N are acceptable, any other 
key producing a request for another input. 

[ i you have a complex decision point in a 
program, such as selection from a menu, ihen 
you can use several If-Then tests but things 
can. soon start to look very messy and 
complicated: 
100 IF A- 1 THEN 1000 ELSE IF A- 2 THEN 

2000 ELSE IF A = 3 THEN 3000 ELSE IF 

A = 4 THEN 400TJ ELSE IF A = 5 THEN 

500O ELSE PRINT TOO BIG'* 
In such situations On Goto or On Gosub can 
usefully be used instead. The form of this is 
On expression Goto line number list, where 
the line number which control passes to is 
determined by the value of ihe expression. 

If numbers are used in the menu then these 
can be evaluated direuilv: 
100 ON A GOTO 1000, 2000. 3000,4000, 5000 

ELSE PRINT "TOO BIG" 
To use the letters A to £ instead of numbers 1 
to 5 you can input AS, determine the ASCII 
value of this, and then subtract 64 and 
continue with line 100: 
80 INPUT AS 
90 A=ASCtA$)-64 



YOLFfi COMPUTEH APWL 1983 39 



No home computer will succeed without 
quality software and plenty of if. The Dragon 
32 has been both praised and criticised for 
shying away from state-of-the-art technology 
in favour of the tried and tested. In spite of the 
unfashionable 6809 CPU quantity of Dragon 
software is not a problem* but how docs the 
quality stand up? 

Presentation varies widely from cheap 
cassmes with hand-written labels to custom- 
made book- type cases with program notes or 
separate detailed instruction manuals. Most of 
the program* were easy to load. 

Since the Dragon and the Tandy Colour 
Computer use pretty much the same version 
of Microsoft Colour Basic, interconversion of 
programs was an obvious idea, although there 
are significant differences between the two 
machine*. 

As the cassette-operating systems differ, 
most Tandy tapes will not load on the Dragon, 
and only some Tandy cartridges operate 
correctly, as certain ROM routines are not 
identical. Only one software house — 
Microdeal — seems to have followed this 
route, via licensing deals, for some of the best 
Colour Computer machine-code software 
from the U.S.A. We found some of the 
original author credit lines intriguing M we 
thought Tom Mix was a pre-war western hero 

— although as the author of Donkey King and 
Katerpillar he is certainly no cowboy. 

Assessing programs is always difficult as we 
all appreciate different things. An arcade-game 
freak looks for close similarity to the original 
bui many people want originality rather than a 
re-hash of tired old ideas. 

Most adventures were traditional text-only 
types which scarcely exploited the Dragon's 
capabilities j, but they were quite cheap, Taipan 
is a trading game set in the China Sea, where 
you travel from port to port buying and 
buccaneering on the briny- Other adventure 
games take place in mazes where you mam 
around collecting valuable objects and 
weapons, and facing many perils. Scenarios 
range from seeking treasure in Egypt, questing 
for the Holy Grail, rescuing stranded 
potholcrs in the Mendips, and finding the Orb 

— whatever that is — we have not found it yet. 
Pharaoh's Curse from Apex Trading did not 
seem too powerful and we thought rescue 
from Death's Head Hole — by Words and 
Pictures — the most original and interesting. 

3*D Maze by Impact Software is graphics 
only and rather simple. It involves collecting 
treasure and finding your way out. On the 
other hand Phantom Slayer, written in 
machine code, is very fast. It is difficult to zap 
those hooded phantoms before they get you. If 
the first shot does not kill it, then run. 

Starshfp troopers 

Dragon Trek from Salamander, and Dragon 
Trek from S W Winter both featured mixed 
text and graphics on the high-resolution screen 
and were in real time. This means you cannot 
wait for ever to make your move. The 
Salamander version had the largest visual 
position display, an excellent damage control 
centre, nice messages from the crew and 
allowed you to steer photon torpedoes with a 
joystick, but we must say that the Winter 
version was also excellent value for money and 
the picture of the Enterprise in the title 



C^A30N 



Once upon a time the Dragon was 
a fine machine with no software - 
but now the Brains have picked 
the best from 100 good programs. 

Ski 



SOF 




sequence was magnificent, 

Trojan's version gave a 
ioystck option, and a very 
comprehensive display cm the 
low resolution screen but the 
commands were tricky to master. Impact's 
Star Trek was cheap, hence there arc some 
limitations; but it is worth considering if 
your Pockets are feeling the strain, 

Star Trek III finds it somewhat hard to 
compete at its price and the Barnsoft version, 
only using high-resolution in the introductory 
sequence — which seemed interminable — had 
very slow response to commands, and fighting 
Klingons seemed a pretty random process. 

The most impressive adventure tested was 
S W Winter's The Ring of Darkness, which 
really flexes the Dragon's muscles. A scries of 
sub- programs, each of which is loaded 
separately, under program control and each 
constituting a good game in its own right make 
up the fabric of this game. Having decided 
what sort of character you want to be, and 
what particular skills you need, you find 
yourself on a complex high-resolution map 
and set out on your search for four rings. 

Do you visit a town or buy provisions, 
weapons or spells and perhaps do a little job 
on the side for the king, or do you explore 
deep dark 3-D dungeons infested with giant 
bats, rats and skeletons? How can you reach 
those islands, and can you cope with the 
constant attacks of various foes? A very 
complex adventure which could take a lifetime 
to solve. This soon displaced breakfast 
television in our house. 



b 34 11 



Many compendia of games, of varying 
quality, arc on offer but all reviewed here offer 
a reasonable range of programs at a fair price 
and can be recommended, particularly to new 
users. The best buy must now be the recent 
Games Tape I from a new source — Active 




40 VOUB COMPUTER, APRIL 1 983 



SURVEY 

WARE 

Software — which has taken some established 
ideas and implemented them beautifully using 
ill of the Dragon's facilities cleverly. There 
are eight games, several of them as good as 
those offered elsewhere as individual cassettes. 

In Interplanetary Trader you voyage the 
galaxy for blatant personal gain, dealing with 
the bank, and avoiding various perils, whilst 
keeping you ship in one piece. 

Execution is a colourful re-intt-rpretaton of 
Hangman with a first-class moving high- 
resolution display of a firing squad in place of 
the scaffold, and a tuneful rendering of the 
Mexican Hai Dance. Wumpus Mansion is a 
game with two mazes, you travel the first 
seeking treasure and avoiding Wumpi — 
revolting things - and race through the 
second if you have the misfortune to trigger a 
time-bomb. 

Wipeout is a variant of the old snake idea. 
You slither around the screen collecting items.. 
but not crossing or going back on your track. 

Hi-Lo is rather like "Play Your Cards 
Right" but has the advantage of doing without 
Bruce- Forsyth. Snail's Pace makes a change 
from horse-racing, and Atom Hunt requires 
some bratnwork, but Air Assault is just good 
old-fashioned aggression as you bomb the city 
to make enough room to land your helicopter. 

A series of innovative family-orientated 
mulii-piayer games come from Shards 
Software, Dragon Furl and Games is excellent 
for children's parties. 

The first Gem Pack, from Gem Software) 
offers four games of skill, the second Gem 
Pack offers two skill games plus two strategy 
games, and the third complex versions of 
Re vers i and Pontoon. 





U 4fc 4fc- ^> 

£ # 32 *> 



:: 



J C Morrison's tapes are excellent for your 
arcade games fans as they each contain three 
diverse and very fast machine-code programs, 
DGT2 contains Snakes, Lander and Invaders 
and DGT4 feature Pterodactyl, Torpedo Run 
and Hornet. 

Garland Software has released physics and 
biology programs, which arc particularly 
useful to schools. All programs use both text 
arid graphics, repeatedly question the user on 
his knowledge, and allow any section to be 

repeated. 

Useful animation is included in Action of 
the Heart — showing blood (low and electrical 
activity — and Principles of the DC Motor — 
especially the perspective view of a moving 
motor at the end — and the Ohm's Law 
program features a useful simulation of an 
experiment which requires you to take 
readings fryin the screen, checks your 
accuracy and plots a graph of your results, 

The educational value of these programs is 
high and our only real criticism is the jump- 
back from the high-resolution pictures to the 
text screen when user input is required, which 
makes it more difficult to consider your 
answer. 

Skill may mean different things but arcade 
games are the highest test of reaction and 
co-ordination. Microdeal has an extensive 
range of first-class machine-code look-alikes of 
all the favourites. Planet Invasion is very hard 
and if you are fed up with zapping and being 
zapped then try Donkey King: rescue the fair 
maiden from that maniac gorilla with the 
endless supply of barrels by lumping and 
hammering at the right moment. 

The popularity of golf programs was a 
surprise — surely people play golf to get out in 
the fresh air, or is the 1 9th hole merely a 
substitute for the one-armed bandits? 

The best — for the true golfer — is 
Salamander's. It closely approximates the 
actual game procedure, includes wind, sloping 
greens and an obvious thud when your 
trajectory ends in a bunker. The use of a 
movable aiming point rather than compass 
directions is particularly good. Apex offer a 
much cheaper and quite reasonable high- 
resolution alternative. For the non*go!fer who 



just wants another game, or for youngsters, 
the low- resolution Handicap Golf from 
Computer Rentals is perhaps your cup of tee- 
Grand Prix, from Salamander, allows one or 
two players to try their driving skill with the 
joystick on versions of all the major motor- 
racing circuits of the world, or if ihat is too 
easy what about Hying a Jumbo Jet? 747 
Simulator — from DACC — lets you try cold- 
start, warm-start and landing approach and 
has a very complex and realistic flight-deck 
display. Keeping control of the 141 is hard 
even wiihout the occasional systems failures 
which were generated — I wonder what 
Boeing would have to say about this — and 
tlying this program is a real simulation, rather 
than just another game. 

Dragon slaying 

Tenpin, by G Newman, was a reasonable 
simulation of bowlingj including an accurate 
update of your score card on screen, but the 
ball was rather small and dillkult to see. If you 
are stuck on the space theme UFO — 
Computer Rentals — allows you to pit your 
wits against 10 different types of alien ship 
and Luna Lander — St George Software — 
was quite difficult. 

We nominated St George and the Dragon 
from Computer Rentals as the most original 
and amusing game. This is an animated 
graphics program in which you kill — or avoid 
— the fire-breathing dragon, cross a river, and 
smite a magic rock asunder with your sword to 
release the princess. Two versions were 
included, for joystick and cursor keys, the 
former being extremely difficult and the latter 
merely impossible. Killing the dragon is a 
cinch compared with balancing on the bridge 
and swimming with armour on. 

If brainpower is your forte then consider the 
games of strategy. St George Software's 
Checkers was simple — and cheap — but still 
beat us, so what hope did we have against 
Salamander's three-dimensional Vulcan 
Noughts and Crosses, Ho wonder the latter 
has a zero player option where the machine 
tries to out -think itself as you sit back and 
watch in amaziuent. In MC Lothlorkn's 
(continued on next page} 



VOUR COMPUTER. APRIL 1 9S3 4 1 



i 'continued from previous page/ 
Samurai Warrioi you have to weigh Up which 
of your colleagues to fight to the death, but t he- 
graphics are rather slow and predictable. 
Tyrant of Athens, also by Loth lor ien, is .1 
better idea, representing the Hellenic Wars. 

For those planning World War III there is 
the more complex Strategic Command from 
Romik where you build up and deploy your 
land and sea force* Again si the enemy. 
Keeping truck of the entire disposition of your 
forces, and selecting targets, becomes difficult 
and we deplore the absence q{~ an :irn*s 
limitation conference option. 

If money, rather than military might, takes 
your fancy then invite your friends in for a 
flutter at Charm Computer Software's 
Roulette, where the wheel stands still and the 
ball goes round, bui the bank still wins. An 
alternative multi-player money game in Space* 
Monopoly from MicrodeaL You must Select 
your Outposts and make your investments with 
due regard to the possibilities of expansion 
and takeovers. 

Wizard Wars from Salamander is a clever 
technological development of the old 'Taper- 
stone-scissors" schoolyard game, in which 
teams of wizards select diabolical and 
protective spells as they battle to desiroy each 
other. There is a whole book of complex spells 
with differing potencies, energy requirements, 
and possibilities of backfiring, to be learnt if 
you are to triumph. 

An increasing range of Dragon utilities is 
appearing. Artist's Designer from S VX Winter 
allows you to const rua high-re solution 



drawings with case and also to write text on 
the high-resolution screen. Character 
Generator — Gem Software — allows you to 
define your own high-resolution character set 
on a nine by seven matrix, and Save this for 
use elsewhere. It makes character definition 
easy and detailed written instructions are 
supplied, but in use text appears rather slowly 
as PSci rather than Draw is used. An interest- 
ing 3-D demonstration of the manipulation of 
an image in thrce-d miens ions is included. 

Micro Musk Map, from Cotswold 
Computers, is a chart giving conversions from 




tf ft Hfefi 



L *+- 



*° 



sheet music to Dragon Flay format, 
particularly useful to non-musicians who 
wants to include tunes in the program. 

Compusense's Demon — cartridge — and 
PSS's Dragbug — cassette — both provide 
monitors which allow you to inspect and 
modify memory and register contents so that 
you can create your own machine-code 
programs. As the main part of Demon resides 
ID the cartridge area, little user memory is 
taken up and, whilst Dragbug includes a dis- 



assembler and a printer driver, Demon allows 
you to inspect memory in ASCII format, and 
include various monitor subroutines in your 
own programs. Demon also comes with clearer 
instructions, and is compatible with other 
software to be released by Compusense — 
including an editor-assembler. The dis- 
assembler from Rampage gives output of 
selected memory contents to screen and 
printer in standard 6809 mnemonics. 

The two text processors Telewriter from 
Microdcal, and Textstar from PSS, could both 
be used as word processors and indirectly, to 
produce and edit Basic programs with the 
benefit of a full-feature editor. In this 
application the value of the Dragon's "real" 
keyboard becomes particularly apparent. Both 
programs provide a useful range of text- 
handling facilities including full-screen 
editing, moves, search and replace, formatting, 
cassette saving and merging. Textstar also 
includes alpabetical and numerical sort, line 
and column display, and tight justification, 
ind is relatively inexpensive, but it uses the 
normal limited Diai',on text screen and 
character set. As a real word processor 
Telewriter — U.S. transplant via Microdeal — 
is much more practical as it provides true 
upper and lower case characters on a black-on- 
while, 51 columns by 23 lines screen display. 
This accepts a wide range of printer control 
functions, block copy and delete, selective 
search and replace, word and line count, page- 
numbering, Verify, auto-retry during file 
search, partial Save and Print, queucing of 

Scontinued on page 45) 



Type 


Supplier 


ffayers 


Price 


Origin- 
ality 


ACCU 
racy 


Type 


Supplier 


Players 


Price Origin- Accu- 
alky racy ' 


Adventures 












Dragon Space Mission 


10 


l 


£7.95 - 


Text otify 












Dragon Monster Mine 


10 


1 


£7.95 - 


Orb 


11 


1 


£5,00 


* * 


— 


Katerpillar 


14 


1 J 


£8.00 "*■ 


Pharaoh's Curse 


2 


1 


£4,96 


. m 


— 


Invaders Revenge 


14 


120 


£6.00 - **" 


Rescue from Death's 












Pianet invasion 


14 


1 J 


£8.00 


Head Hole 


25 


1 


£4.45 


mt * 


|M 


Scarf man 


14 


1 O 


£8.00 - 


Taipan 


12 


1 


£5 00 


tli 


V * 


Dragon Gold 


10 


12 


£7.95 * 


The Quest 


11 


1 


£5.00 


* 1 


— 


Golf 


20 


12 


£7.95 *' 


Graphics onfy 












Golf 


2 


1-2 


£4.96 ** *** 


Phantom Slaver 


14 


1 


ES.00 


« * •* 


— 


Handicap Golf 


6 


12 


£6.95 " 


3D Maze 


11 


1 


£5.00 


14 


— 


Grand Prix 


20 


1-2 J 


£7.95 "" 


Text »n<t Graphics 












Luna Lander 


22 


1 


£4.00 


Ring of Darkness 


24 


1 


E10.00 


« fl • -ft ■ 


— 


St George and the 








Star- Trek 












Dragon 


6 


1 O 


£6.95 *««•■ 


Dragon Trek 


24 


1 


£6.99 


— 


* •* * 


Tenpin 


16 


1 


£7.00 


Dragon Trek 


20 


1 J 


£9.95 


— 


.. ■ . . 


UFO 


6 


1 J 


£695 


Space Trek 


23 


1 O 


£7,50 


— 


* * 4 * 


747 Simulator 


8 


1 2J 


£9.95 *"* 


Star Trek 


3 


1 


£6.50 


- 


■ * 


Strategy 








Star Trek 


11 


1 


£5.00 


— 


m * * 


Checkers 


22 


1 


£3.50 * *■** 


Star Tiok III 


22 


1 


£8.00 


— 


m m ■ 


Roulette 


4 


19 


£4.95 •" •*** 


Compendia 












Samurai Warrior 


13 


1 


£6.95 " 


Dragon Family Programs 


21 


V 


£6.00 


* * i * 


— 


Space Monopoly 


14 


24 


£8.00 


Dragon Fun and Games 


21 


V 


£6.00 


» * * w 


— 


Strategic Command 


19 


2 2J 


£9.99 ***' 


Games Compendium 


20 


V 


£7.95 


* ** 


— 


Tyrant of Athens 


13 


1 


£6.95 "■ 


Games Pack 1 


10 


V 


£7.95 


* * 


— 


Vulcan Noughts and 








Games Pack 2 


10 


V 


£7.96 


* *> 


— 


Crosses 


20 


0-2 


£7.95 •" 


Games Pack 3 


10 


V 


£7.96 


_ 


.... 


Wizard War 


20 


2-9 2J 


£7.95 


Games Tape 1 


1 


V 


£5.75 


«*■>*- 


— 


Utilities 








Dragon Games 2 


15 


1 


£6.95 


— 


.... 


Artist's Designer 


24 





£6,99 ■« 


Dragon Games 4 


15 


1 


£6.95 


— 


. 4 . . 


Character Generator 


10 




£9.95 *■ 


Educational 












Demon 


5 




£18.40 **" 


Action of the heart 


9 


- 


£11.00 


... 


*»*• 


Disassembler 


18 




£5,00 * 


Digestive system 


9 


— 


£9.90 


. . * 


.... 


Dragbug 


17 




£9.95 " 


Ohm's LttW 


9 


— 


£5.00 


. . * » m 


. ■ 1 + 


Micro Music Map 


7 




£3.50 •« 


Principles of the 












Telewriter 


14 




£50.00 •*•-* — 


DC motor 


9 


— 




t - . . 1 


i * . * 


Textstar 


17 




£11.95 "■ 


Skill 












Threedee 


22 




£5.00 •" 


Defence 


14 


1 H 


£8.00 


— 


• *1 > 


Table of games reviewed. 


J means joysticks reautrecf; O means 


Donkey King 


14 


1-2 J 


£8.00 




» . ■ ■ 


joysticks are optional, and V means the number of players varies. 



42 YOUR COMPUTER. APfiJL 1983 



PLAY YOUR CARDS 

RIGHT 



THE INTEGRAL 
EXPANSION SYSTEM 
FOR VIC-20 



•*••*. 








Congratulations for choosing one of the best home computers around. Unlike Commodore, 
we still think that the VIC 20 is great , and doesn't need replacing by a big brother. Here is the 
result of careful design, hearing in mind many similar products from Commodore, Stack and 
Affon: an integral expansion system which is practical, reasonably priced and compatible 
with Commodore products and many others. The system features many exclusive qualities 
in addition to those of its competitors. It consists of 4 items, each of which may be purchased 
separately and used independently 

• 3 SLOT MOTHERBOARD: This is a simple box plugging straight into the VIC 20, 
providing support for various cartridges, Et comes with a switch to isolate the Super Expan- 
der Cartridge from Commodore, a switch to simulate games cartridges, a battery back up 
connector* and (here is also room for 8K of extra Ram if required*. 

• A SPECIAL RAM CARTRIDGE: This can be used instead of the Commodore cartridge, 
and offers 16K of extra RAM. A further 16K can also be added, giving 28159 bytes free for 
Basic and 8192 bytes free for machine code. 

• A SPECIAL EPROM CARTRIDGE: This is designed to offer access speed of disk, 
security il ROM and ease of use with Tapes, Basic programs and games cartridges can be 
copied into the Eprom cartridge and played back at any time. 

• A 40 column ROM: This will be available towards mid-February. It will enhance the VIC 
display to 25 lines per 40 columns and offer the facility of adding 8 second processor (Intel 
BOSS). 



• TECHNICAL SPECIFICATIONS 



MOTHERBOARD: i x 22 way gold plated connectors. Accepts all Commodore car- 
iridKcs. Accepts Toshiba 20 16 sir Hitachi 6 1 16 CMOS Ram (qly: 4), Write protect twitch 
filled. Mode switch and battery connector fined only when supplied with SK Hitachi 
Ram. 

• SPECIAL RAM CARTRIDGE: uses single SV supply Dynamic Ram Transparent 
refresh without slowing processor speed. Access time: 250ns maximum. Capacity: l&Kor 
32K bylei, addressed fromfi 2000— 7FFF andSAQOO — BFFF. Switch fined to partially 
disable any BK memory Mock, 

• SPECIAL EPROM CARTRIDGE: Memory capacity: upto32K Eproms(4 x 2764s). 
Programs liproms from Basic or Machine code programs or directly copies ready made 
cartridge*, All saved programs have separate entry to the Eprom catalog {held in the first 
Eprom.) and can be loaded bafk and run at any lime. Addressed fmm.fi 9800 — °FFFand is 
compatible with all Commodore can ridges,. 

• 40 COLUMN ROM (ADVANCE INFORMATION ONLY): «K bytes. Can com. 
municait With 2nd processor Via 2K dual port Ram and interrupt. 



THE MOST PRACTICAL 
SYSTEM FROM: 



19 



ONLY. 







Wj&L* 



vJW 









*&A9 






& 



« 



# 



-& 



cs 






*S 



V 



Please note that each of the above products is normally 
available il your local computer store. You can also order 
them directly from us by mail or telephone. Thank you for 
the lateral shown. 



AUDIO-COMPUTERS 

47 BOURNEMOUTH PARK ROAD, 
SOUTHEND-ON-SEA - ESSEX SSS 2JJ 
TELEPHONE: SOUTHEND (0702) 613081 



35 



<- 



$■ 






<" 



V 



^v 




^^nt " jLj 


mmgm 

^i 1 '*'" 1 


1 TEw&S^K^;* 


a! 


J IS 




L— ^' J? 



ORBITER 



A fast and f uncus arcade action game for the 
ZX Spectrum, Orbiteris written entirely in m/c 
code with full arcade features including scan- 
ners, reverse, hyper-space, continuous scor- 
ing, sound effects and humanoids. 



GROUND ATTACK 



Survival is the name of the game in this exciting 
scramble-type arcade game. Fast machine 
code action with full arcade features, 



MUNCHER 







TARSHIP ENTERPRISE 



Fruiteatingmonsterbeat<ngmazernunching 
creaturecmnchingghostchasingfastame^mg 

Muncher! Fast machine code, maze, race 
and chase game, 



ZX 81 Arcade Action List 






ZX81 Compiler 




□ 


£5.95 


Muncher (ZX 81) 




□ 


£4.95 


Asteroids 




□ 


£4.95 


Invaders 




□ 


£3.95 


Alien-dropout 




□ 


£3.95 


Startrek 




□ 


£3.95 


Graphic Golf 




D 


£3,95 


Super lAlumpus 




□ 


£3.95 


Games Pack 1 




□ 


£3.95 


Please send me as 


indicated. 




I en 


NAMF 









Soar through the scars in this exciting new 
space ship simulation. This new. advanced ver- 
sion of Startrek uses the full colour and sound 
facilities of the Spectrum microcomputer. 



ZX — Spectrum Software 

arbiter 
Ground Attack 
Starship Enterprise 
Muncher 

GENEROUS DEALER 
DISCOUNTS AVAILABLE 



□ £5.95 
£5.95 

G £5.95 
£5.95 



SILVERSOFT 

2 Hammersmith Broadway, London WC6 



I enclose a cheque/PO for £. 



ADDRESS 



PROGRAMMERS. Tired of working for nothing, send your programs to SILVERSOFT for a speedy reply. 



(continued from page 42) 

cassette files for Print, and repeat headers. 

Cassette files are saved as very compact 

machine-code dumps rather than the 

extremely slow ASCII format used by 

Tcxisiar. 

Four different versions, optimised for 
different printers, arc included, together with 
3 Conversion program for work on Basic 
programs. First-class documentation 
comprising a step by step tutorial and a 
reference manual are included and Telewriter 
represents excellent value as a word processor 
for the serious Dragon user which, at £50, 
looks very good in comparison with Wordcrsft 
for the Vic-20. 

CONCLUSIONS 

■ An excellent range of games soft- 
ware for the Dragon has emerged, at 
prices which compare well with materia! 
for competitive machines, and 
substantial offerings on the serious side 
are now appearing, ell of which augurs 
well for the future of Dragon Data. 

■ Various rumours are circulating 
about hardware modifications, ROM 
bugs and RAM reconfiguration which 
can cause problems on some machine- 
cede programs, so it you have a 
program that runs into difficulties 
consult your supplier. 

■ One point to watch when using 
programs one after the other is the last 



Softwwe suppliers^ Numbers correspond wtth those given in the table of games reviewed. 


1 


Active Software, 32 Moor* Lane, 




Cheadle Hume, Cheshire SK8 6LS. 




Northfield, Birmingham B31 10H, 


14 


Microdeal. Deal House, Luxyian, 


2 


Apex Trading, 115 Crescent Drive 




Bodmin, Cornwall PL30 5EF. 




South, Brighton BN2 6SB, 


15 


J Morrison Micros, 2 Giensd&te Street. 


3 


Barnsoft. 43 Waverley Road, 




Leeds IS9 9JJ, 




Portsmouth, Hampshire*. 


IS 


G Newman, 12 Maiden Park, New 


4 


Charm Computer Software, 243 Shirley 




Mfilden. Surrey. 




Road, Acocks Green. Birmingham B27. 


17 


PSS, 452 Stonoy Stanton Road, 


5 


CompuServe, PO Box 169, London 




Coventry CV6 5DG, 




N13 4HT. 


13 


Rampage. 32 Birchwood Drive, 


6 


Computer Rentals , 140 Whitechapel 




Wilmington, Dartfprd, Kent DA2 7NE. 




Road, London El. 


19 


Romik Software, 24 Church Street. 


7 


Cotswold Computers, Park Hill, Hook 




Slouch SL1 1PT, 




Norton, Oxfordshire. 


20 


Salamander Software, 27 DitChling 


8 


OACC. 23 WaverSey Road, Hinderley, 




Rise, Brighton, East Sussex 6N1 4QI. 




Greater Manchester WN? 3BM. 


21 


Shards Software, 10 Park Vale Court, 


9 


Garland Computing, 35 Dean Hill, 




Vine Way, Brentwood, Essex, CM 14 




Plymouth PL9 9AF. 




4UR, 


10 


Gem Software, 22 Prestwick Drive, 


22 


St George Software, 6 Storrsdale Road, 




Bishop's Stortlord, Hertfordshire CM23 




Liverpool LIS 7JZ, 




5ES. 


23 


Trojan Products, 166 Derlwyn. 


11 


Impact Software, 70 fledford Avenue, 




Dunvant, Swansea SA2 7PF. 




Edinburgh EH 13 OBW. 


24 


S W Winter & Co. 101 Westminster 


12 


Jaysgtt, 6 Wenfworth Drive. Bishop's 




Bridge Road, London SE1 




Stanford, Hertfordshire. 


2S 


Words and Pictures, 7 Hawthorn 


13 


M C Lothlorien. 4 Gran by Road. 




Crescent, Burton-on-Tiew DEI 5 9QP, 



state of ihe reserved graphics pages. 
These can easily cause out -of memory 
errors on the next program if you do not 
turn off between programs. 
A final word to small suppliers — 



please remember multiple copies are 
realty no substitute for a decent 
recording. There is nothing so 
frustrating as a program that will not 
load. ■ 



DRAGON SOFTWARE 






FOR ALL THE FAMILY © 9 



FAMILY PROGRAMS . . . £6 

• Sir a legit: tank battle for 2 players. 

• Educational maths qui* \3 levels). 

• Guess the tune! [100 songs) 1/2 
players, 

• Comprehensive mortgage/savings 
calculator. 

• Massive 750 question Quiz for 1 2 
players, 

• "Simon"-type memory game. 

• "Day- of- week" calculator. 

• Test your speed of reaction. 

• "Chase the face" across the 
screen. 

• Anisis sketch pad. 

• Thread the ring through the wire, 
1-6 players. 



FUN AND GAMES 



£6 



• Hi res noughts and crosses (2 
levers}, 

• Brain teasing mastermind test. 

• Rant>' n gainst time to collect the 
gold, 

• Play card game, "Snap" against 
the Dragon. 

• Un jumble the town name 
anagrams, 

• Pin the tail to the donkey! 

• Who can score the highest at 
poker dice. 

• Pair up the coloured circles. 

• Create and compare your 
computer art, 

• Let the Dragon control your party 
games. 



LIVE AND LEARN . . . £6 

• Step by* step tutorial. exploring 
the mysteries of High- resolution 
graphics. 

• Facts and figures about favourite 
zoo animals with world map and a 
qui?. 

• Educational tour of England, 
Scotland & Wales, 

• Instructional quiz on towns and 
cities of Britain. 

• How would you survive in a 
desert? Try the quiz, then learn the 
facts. 

• Play your own tunes end teem 
about music notation. 



CITY DEFENCE 



£5 



exciting missile command arcade game for joystick, With good sound, colour and graphics 



GENEROUS DEALER DISCOUNTS. SEND NOW FOR OUR STARTER PACK OFFER 



HEAR WHAT THEY HAD TO SAY: 

"Well thought out programs, made better by professional 

presentation and full use Of Dragon facilities" Popular Computing Weekly 

{Ft/ft AND GAMES) 
"Very enjoyable, exceflent quality". CG of Colchester (FAMiLY PROGRAMS) 



• 43 HOUR DESPATCH &V 1ST CLASS POST 

• LIFE-TIME REPLACEMENT GUARANTEE 

• AUTOMATtC MEMBERSHIP OF SHARDS 
USFR CLUB {with discounts end newsletter) 



SEND CHEQUES/ POs 
To: 

(Prices include P&P} 



SHARDS SOFTWARE 



At: 

10 PARK VALE COURT 
VINE WAY, BRENTWOOD, 
ESSEX CM14 4UR 



YOUR COMPUTER, APRIL 19B3 45 




Hewson Consultants 

We proudly announce our 1983 range of 
SPECTRUM 




IMIGHTFLITE 16 and 48K FLIGHT SIMULATOR 



MG HTFLITE puts you at the controls of a 

Nght aircraft flying at night. You can: ^ h 

Clfrnh, descend, takeoff, ^lj . 

Land, bank left or right, HOG ■ 

N avi ga re be t wc e n boa cons. pj_ 

Raise/lower the flaps, qr 

Raise/lower the undercarriage, yg| 

Adjust engine rpm, WIND- 

Raise/lower the nose varying amounts DME 

Runway lights appear on approach, ADF - 

5 modes including Autopilot. IIS 

Written by a qualified light aircraft pilot. VOR - 



artificial horizon 

altitude in ft 

heading in compass degrees 

flaps up/down 

gear up/down 

vertical speed indicator 

wind direction/velocity 

distance me asure equipment 

automatic direction finder 

instrument landing system 

VHF omrti directional range 



£5.95 



our runs way bestseller 



Available through WH SMITHS and many independent micro-computer shops 



COMING SOON:- AIR TRAFFIC CONTROL -Puts you in command at Heath row Airport £5.95 




4 



MAZE CHASE 

1Gand48K 

4 or 8 M aze s , Hi g best score to date, 
4 i n dependent gu a rd i a n s , 3 1 i ves. 
Full colour. Fast machine code action. 



£5.95 

All action game 



£5.95 

Are you 
fast enough? 



► 




SPECVADERS i6K 

Defeat each squadron of Beeple Zaps 
and another appears only closer 
Cyrianrnothership with ejecting Zeetle 
Baps. 



5 levels of play from Orionssnatls pace 
to close your eyes and hope- 
Real lime scoring. 3 lives. Pan galactic 
gargle blaster for highest score. 
Descending asteriods. 




4 



BACKGAMMON %sk 

& Levels of play from novice to expert . 

Full colour display of tables and dice. 

Ga m b le n a s ing I e ga me ora series, dou b I e or 

quits. All the features of the ancient game. 



£5.95 

A rest challenge 



£5.95 

Another first 



► 



COUNTRIES 
OFTHE WORLD 

16 and 48K on one cassette 
Countries of the world is an 
educational package designed to give 
an a pp reciat io n of t h e \ ocali on of a 1 1 the 
main countries and some information 
about them. 
16K version displays a world map. 




shows the position of each country and 
names its capital. 

48K version ; a) I the a bove p lu-s pri n ts 
the popular ion, size, currency, and 
m a i n I a rig u ao es of each cou n try, and 
statistics on largest and smallest 
countries etc. 



■S6 VOUR COMPUTER APRIL 1 983 




Hewson Consultants 

SPECTRUM BOOKS 



1 Wt»M*fcCEKK.W>SWK& 



%^ TXSPtcrajH 



40 BEST MACHINE CODE ROUTINES 
FOR THE ZX SPECTRUM 



£5.95 








By Andrew Hewson and John Hgrdmgn 
Section A : T h ree cha piers expla i n ing wh al you 
n eed [o k now about Z80 mech i n e code on th s 
Spectrum. 

• How to load and save machine code. 

• How to use the system variables, 

• How memory is organised. 

• How program lines are stored. 

• How to use the stack the display the 
attribute files. 

• How to call ROM routines -wherethey are 
and what they do, 

9 The structure of Z8Q code- plus a valuable 
glossary. 



Secti on B : 40 ro u ti nes i n clud i rig , 

9 S c rol I - up. down , si de to si de by pi xei or by 

character. 
• Search and replace, token swap, string 

search, 
9 R ota te c ha ra cte r , j nvert cha recta r - 

horizontally and vertically, 
9 Line renumber- including GOSUBs, 

GOTOs, RUN etc. 



This book teach es the beginner all he needs to 
know in a simple, easy-to-learn form and its an 
i nva lua ble re fe rencc wo rk f o r the expert too ! 



ttftW*vr-«»* 



Ava i I a b I e th ro u g h Com pu te r Books hops 
andWHSMlTH. 




20 BEST PROGRAMS FOR THE ZX SPECTRUM £5.95 

By Andrew Hewson 

Program titles include: 

Machine Code Editor-Write, modify, extend 

and load machine code using this all-basic 

program. No need to use an Assembler when 

you have this program. 

Index Fits- Learn about fixed length records, 

save numericand string information, add to, 

sort, modify, delete and print your records. 

Ideal as a computer based f i ling system. 

Duckshoot - Learn how to manipulate the 

ZX81 
BEST SELLERS 



attributes fife andhave fun at the same time. 

Graphix - Construct up to 210 graphics 

characters with the full on-screen editing 

facilities, enhance and modify them and recall 

them later to bu i Id a data il ed d isplsy to save on 

cassette. 

Spiromania - A program to stretch your artistic 

taiants, imagination and ingenuity. Draws a 

limitless variety of curves and spirals, 

Plus: FOOTBALL. DIGITISER, DIARY and many 

more. 



PILOT 16K(zx8iJ £5.95 

Fly your own aircraft 

Instruments : 

Artificial Horizon, 

Automatic Direction Finder, 

Instrument Landing System. 

Readouts: 

RPM, Flaps, Heading etc. 





PUCKMAN 16K(ZX8!)£5.95 



HINTS & TIPS FOR 
THEZX81 £3.95 



Passing data between programmes. 
Calling subroutines from cassette, 
Machine code programmes, 
Bits, bytes, addresses and hexodecimal plus 
much more. 



3 Mazes. 

Hi ghesl sco re t o date , 

4 Independent guardians. 
Magic strawberries. 



RETAILERS 



We are continually en the look out for new 
Outlets, if you are interested in stocking 
the items advertised here, write to us for 
our trade rates. 



URGENT 

We require high quality Spectrum and 
Dragon software. Good royalties paid. 
Send your samples today for fast 
evaluation. 



THE PROGRAMS 

Th e progra ms ad ve rti s ed here are 
available from computer bookshops with 
a softwa re sta n d", a nd m a n v i nd epe ndent 
micro-computer shops. 









ORDER FORM MakadiequHWs payable to 

Hewso n ConWtii rts 

Quantity Product 


YC3 


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p 




Name Total 




{Block Capitals PJeaaer) 
Address 



Signed. 



My Access/Barclaycsrd No. is. 



Post to : H EWSON CONSU LTANTS. 60A St M a ry 's Street, Wa I li ngfo rd , Oxon 0X1 0E L . 
Tel (0431) 36307. 

YOUR COMPUTER, APRIL 1983 47 



SEVERN SOFTWARE 




SPECTRUM - ORIC 

ROADRUNNER QUINCY 

SPECTRUM 1BK & 48K £4.95 inc. SPECTRUM 48K £5.96 inc. 



Everyday from Monday to Friday Mr. 
McGoo gets in his car and drives home 
from the office. Mr. McGoo is such a 
lousy driver that he'll crash into anything 
that gets in his way' 
The roads are full of Mr. McGoos, Can 
you get home from your office without 
becoming one of their victims? 

• Ask for SEVERN SOFTWARE at your 
local Computer Shop- 

• We guarantee to replace AT ONCE any 
cassette sold by us That fails to load on 
receipt. 

• The exact software specification varies 
from machine to machine particularly with 
regard to sound and graphics. 

• Dealer enquiries welcome. 

Pleas* send me 

(Please state machine) 

I enclose Cheque/P.O- for E 

Name 



Address . . . , 



« 1 ■ fc 4 i i 



Pt + itf-tt-.J-' 



Post Code 



SEVERN SOFTWARE 

5 SCHOOL CRESCENT, 

LYDNEY, GLOS GL15 5TA 



1 

1 

I 
I 
I 
I 

I 
I 
I 
I 

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Get the mast from yuut MtCFQ. 

*A specially commissioned version of 
that well known 5- Dice game for 2-6 
players, played and enjoyed by 
families world-wide. 

Why play alone when the whole 
family or a few friends can join in? 
This is not merely a game of chance. 

You can only win by skilful playing. 

Easy to learn but totally absorbing. 

Features: — 

• Full colour and graphic gama 
displays. 

• Individual screen score cards. 

• Dice control 

• Full choice of score card entries, 
based on individual strategy. 

• Hold and Clear facilities for dice 
scores. 

• Earn a bonus score. 

• Snvn game facility. 

Become the QUINCY CHAMP In your 
house. 

•Written by TONY CHURCHER. 



ZX81 

MORIA 

SPECTRUM 16K & 48K f 4.95 inc. 

ORIC48K £4.95 inc. 

'ZX81-16K £4.45inc. 

A challenging gr.iphif adventure set in the 
Mines of Moria. Can you survive 
encounters, with the monsters of Middle- 
Earth? Will the Wizard help you? Are you 
fated to die beside the sealed doors? Or 
hove you the power to open them? Unless 
you find Dunns fling you will never leave 
Hie Mines alive 1 

A game to test your character. 
Sound effects snd save game and reset 
facilities, 

"The ZXS1 version displays each location. 
Collect treasure and find your way out. 

GRAIL 

SPECTRUM 16K&4BK £4.95 inc. 

0RIC48K £4.95 inc. 

2X81-16K £4.45 inc. 

Exciting graphic adventure. Where in the 
Castle Perilous is the Holy Grail? Gather 
armour and weapons to fight Monsters. 
Sell treasure to a Trader. 

Where will the Warp take you to? 
Sound effects and save game facility {not 
on the ZX81 version). 



r q FORTH 



"r q FORTH" runs on 16K or 32K 
BBC iricror-'ana CQUti £15, It; 

* fellows the FOBTH-7Q STANOARO 

*na h»s fig-FORTH facilities; 

* provides 2SG FOftTH word*; 

* is infinitely e»te"3 it lc ; 

* has a full-screen editor 1 ; 

* tl'.oms full yse of the M.O-S; 

* permits uSe of All Graphic 
modes, even 0-2 (juttrt; 

* provides recursion easily; 

* runs ratter than BEJC QASTC; 

* needs no added tiirdwirt ; 

* includes m r page technical 
manual and a summary card; 
has Hundreds c* usen. 



FORTH 
TOOLKIT 



Level *) C«*nOutinq are pleased 

to announce a new tool* it far- 
"p Q FORTH" on 32* «0C micro*. 
It costs, only £10 *nd adds th# 
Following facilities to FOftTH: 

* a 6SQ2 assembler, providing 
machine -code rfitnin FORTH; 

* turtle grkphfea, giving you 
tasy-to-use colour graphics; 

» decompiler routines, allowing 
the versatile eKj.n nation of 
your- compiled FORTH programs; 

* the full douula-numbef set; 

w an * sample FOfiTH program i a no 

d*nonstrati*fts of graphics; 
■ other useful routines. 



no/com 

E.tcfision Bane . E19/C30 ftcr-i 



Aftt-e»*oida, ...... 

Uilaiy Invaders. 



Adds 30 ittw keywords to BASIC 
Compression Assembler 2 . E1Z 




50ur:<; * hi<jn speed 



n.Zc.1 £?.40 

Hi n ilt Defence . ™/e,g tT.Wi 
Super Gulp ....... cb,g £4.90 

-'-gii^es cassette ■ mite £5.00 
(Pull rangc in CATALOGUE) 



aoueritu ties 

Spectrum HJOJ0 fKISCOfff 




1) COLOSSI AQVENTufiE ; 'he classic mainframe game "Adventure" 



■<ith all the original treasures & creatures » 70 extra ffOTi, 

21 ADVENTURE QUEST r Through forest, desert. Mountain*, caves, 
wattr, fire, moorland i'U iMinp on an epic quest vs Tyranny, 

31 DUMSEOW AOVEmTUH£ : Tie vast dungeons of the Demon Lord have 
survived His fall. Can you ,jet to their treasures first? 

Every Level Adventure has Over ZOO individually described 
locations, and is packed with puiiles - a gars* can easily take 
rtionths to complete. Only sophisticated compression techniques 
can souectg f.a nuct -r. 1 Lach gang needs 3ZK and costs £0.30 



ALL PRICES INCLUDE P4P Af*D VAT - THERE ABE NC EXTRA*. Please 
send oreler or SAE for catalogue, desc^ieinj youi~ micro, to; 

LEVEL 9 COMPUTING 

S*pt V, ?,?.$ Hughenden goad. High wycomoe, Bucks. HP 13 SPQ 



PASCAL FOR THE 
ZX SPECTRUM 

Hisoft are pleased to announce the availability of Hisoft Pascal* 4 

for the 48K ZX SPECTRUM, 

No longer do you have to pui up with* the slow execution speed ol 

BASIC programs,; Hisolt Pascal 4 produces programs thai run 

between 40 and 100 h/es 1001 1 times faster than the equivalent 

programs written in ZX SPECTRUM BASIC. For example, a 

program to sort a 100 element array of numbers into ascending 

order takes 60 seconds in BASIC, while HP4 produces a program 

which does the same thing in 0,6 seconds! 

NOW you and your children can learn to program in an efficient 

and structured way by using Pascal, the favoured language in 

schools and universities. 

NOW you can write games programs etc. which run as fasi as you 

need them to without having to resort to assembler oc machine 

code. 

NOW you can use a language which requires minimal re-teaming 

wtien you move from your SPECTRUM to another computer; 

MisoJr Pascal 4 has an the essential features of Standard Pascal as 

detailed in the Pascal: User Manual end Report - by Kathleen 

Jensen and Niklaus Wirth, the man who designed Pascal 

Hisofi Pascal 4 is a professional piece of software designed by a 

team who have been writing Pascal compilers lor many years, - 

you will find it to be powerful, flexible and very easy to use. 

To top it all, we are offering the package [which includes a 60 page 

manual!, for a limited time, to 48 K ZX SPECTRUM users at an 

INCREDIBLE pric& of 

ONLY £25 INCLUSIVE 

STOP PRESS: DEV PAC, our powerful assembler, disassembler 
and debugger package is now available. Only £12,50 inclusive. 

Wrne for more ct&t&i/s TOD A V to: 

H3HI5DFT 

40 Hilltm Moor 
Liden SKTNP3K 

Tel (0793) 26616 (Answering machine) 



46 YOUR COMPUTER. APRIL 1983 



7 

*4. 



DRAGON 



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ANOTHER GREAT (iAME 
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Watch out there's a robot about. 

The BBC Buggy is not alone. From £30 to £2,500 the 

robots are ready to move into your home. 



The Buggy's only competition comes from 
the Japanese toy industry and infant 
American domestic robot industry. 

Tomy's Robu 1 was the star of the British 
Toy Fair at Earl's Court, A toy version of an 
industrial robot arm, it is battery run and 
controlled by two joysticks at the base. The 
firm itsrtl can bn swung up and down 
ihrutKjh 180 degrees and turn 360 degrees 
horizontally. Further dexterity is provide! by 
the wrist which can swivel in almost any 
direction. By con (rolling the Robo 1*s daw 
hand the ojMjrator can grip, pick up, rotate, 
move and release objects with remarkable 
precision. This is a well eonsttucted end 
absorbing loy which selte for just E30 

Like the Buggy the Hero-1 is a pro 

ijr.jirirri.lUN' ttm-*: wheeled vehidl' driven by 
two stepper motors and sotd in kit form. 
Looking like a cross between Or Who's K9 
tind Slar Wars R2D2 it more closely conforms 
to the popular idea of a robot. Unlike (he 
Buggy the Hero 1 is self-contained with an 
on board microprocessor and its own battery 
power supply 1 1 uses a 6808 processor with 
4K RAM and 8K ROM. Instructions are 
entered vta s hexadecimal keypad . 

The Hero-1's range of sensors is far more 
extensive than the Buggy's. As well as a light 
detector it has detectors which can sense 
sound, motion and distance. It uses a sonar 
system to work out the distance of objects 
within u range of eight teet Tlnirt! is also a 
built-in clock and options for a Speech 
synthesiser and g ripper arm. 



This is obviously a more sophisticated 
package than the Buggy and a much more 
expensive one. In the USA. the Hero-1 
robot kit sells for $1,000 without the ami and 
speech synthesiser. Heath Electronics U.K. 
will be launching a Hilly -assembled version 
including the arm and synthesiser for £2.466 



*v* 












-w 



h 



:m 



'w. 



.1 1 



I f - I 



SO VQUft COMPUTER. APRIL 1953 




Designed for the home. 
Built by screwdriver. 
Tested by Simon Beesley. 
Buggy — the world's first 
affordable robot- 




BUGGf 



IF YOU HAVE grown tired of ail those video 
games and, have exhausted your machine's 
programming potential you can now revive 
your interest in computing with the BBC 
Buggy. This is a three-wheeled vehicle which 
can be controlled by a BBC Micro and 
programmed to move in any direction, delect 
collisions;, detect light j read a bar-code^ and 
operate a pen-up/pen-down mechanism. In 
short it is a robot — and at around £120 it is 
the first to come within the range of the home 
computer user rather than the electronic* 
hobbyist. 

The Buggy is the fruit of a collaboration 
beiween the BBC Computer Literacy Project 
and the Microelectronics Education Pro- 
gramme. After discussing ideas for ihe BBC's 
Making the Mosi of the Micro series with 
producer David Allen, Mike Bostock, 
Technology Manager for the MEP, built a 
prototype Buggy using Lego bricks, 
"Everyone wants to build a robot", he says, 
"and at ihe age of 11 I finally built one". 

When the Buggy goes on sale this month it 
will come as a construction kit containing a 
chassis, two stepper motors, three ivpcs of 
sensor, control cables and electronic circuit 
boards, To go with it there is a tape with 13 
programs, documentation, a Buggy handbook 
and assembly instructions. 

Fortunately the review robot arrived ready- 
built so we did not need to test the claims of 
Buggy-maker Economatics chat the kit can be 
easily assembled in about two and a half hours 
using only a screwdriver. 

The main body of the vehicle is a five-inch 
cube driven by two stepper motors 
which turn the front wheels. At the 
back there is a ball-bearing which acts 
as a balance wheel for the vehicle. 

Using stepper motors greatly 
simplifies steering the Buggy since the 
motor can only be advanced by a fixed 
step ai a lime. This allows precise 
control of the vehicle's movement. Each 
motor has independent control over its 
respective wheel and the gearing is such 
that a single pulse to the motors rotates 
the Buggy by one degree. 

It is comparatively easy w send the 
Buggy a specified distance forwards or 
backwards, or rotate it through any 
given angle. The two motors drive the 
vehicle at a rather stately pace with 
sufficient power for it to authoritatively 
brush aside obstacles such as books, in 
bulldozer fashion. 



Top speed was measured at one and half 
miles per hour — hardly enough to trouble the 
man with the red flag. At the front is a split 
bumper with left and right micros witch 
collision detectors and above it a light detector 
— LDR. There is also a bar-code reader — 
BCR — mounted on a hinged arm which 
extends between the bumper and the LDR. 

This consists of an infra-red light -emit ting 
diode — LED — and photo-diode which 
respectively send out and receive infra-red 
light. The BCR detects a black line by 
measuring the amount or light it reflects. My 
only criticism of the vehicle's design is that the 
BCR arm is inconveniently positioned. 
Although it can fold back it lends to prevent 
ihe bumpers below from registering a head-on 
collision. 

Logo-style turtle 

In the Buggy's centre of rotation there is a 
pen-up, pen-down mechanism which is 
mounted on the centre axle and controlled by 
an electro-magnet. This will permit the Buggy 
to be used as a Logo-style turtle. It is not quite 
as accurate as a dedicated Logo turtle but is 
£180 cheaper. 

On the BBC Micro the Buggy is controlled 
through the user and analogue-in ports. Both 
the LDR and BCR return an analogue input 
proportional to the intensity of light 
measured. The collision detectors send a 
digital on/off signal to the user port. 

Each of the user port's eight bits provides a 

control line. Four of the lines from the user 

(continued on page 53) 




YCHJR COMPUTER, APfttL 1 9&3 51 



23ragonS Hair 

I thought it would be easy . . , 
explore the Dragon's Lair and 
find the Crystal of Power with 
which to destroy him, But 1 
didn't count on the dangers that 
confronted me. There were 
others in that mind boggling 
mgze too 1 

The Ultimate 3D Maze- 
Adventure, for the 4BK ZX 
Spectrum. 



Jousst 



It's taken America by storm — 
now it's available for your ZX 
Spectrum! In this amazing new 
arcade game you Joust with the 
Dark Lords in an other-worldly 
setting. Quite amazing animation 
as you fly your Ostrich by 
controlling the flap of its wings! 
By Andrew 'Grbiter Glaister 



MONSTERS IN HELL 

It was like a nightmare, Trapped 
in HelL the all consuming flames 
below me, running from the 
Vampire monsters through a 
maze of platforms and ladders. I 
had Holy Power on my side, 
though, and could survive if l 
replenished it frequently. And the 
only way to kill them was to 
make them fall through holes I 
created with my hammer, But 
then the Mad Monk sent his 
ghouls after me , . . Any ZX 
Spectrum. By Mark Lewis 



COSMIC SWARM 

OK, I accept I'm to blame. I 
disregarded orders and entered 
the Altair sector. Eggs, eggs, 
everywhere I shoot, two 
fantastical alien types appear, 
whose touch is deadly! They join, 
seemingly by chance, into a 
mutant which chases me! 
Probably the most original new 
space 'shoot-em-up' game to 
appear. Any ZX Spectrumn, By 
Andrew Beale 







MILLIPEDE 

Milli the Millipede seemed 
indestructible; no matter how 
much of her body I shot away 
she kept coming! But then Sid 
the Spider appeared from 
nowhere, and Scorpi zoomed 
across dropping her indestructible 
fleas on me! A quite astounding 
version of the arcade favourite. 
£5.95. By Andrew Blake 



ALSO AVAILABLE 
And you can still obtain our 
outstanding Meteofids, still the 
best available, or our Zolan 
Adventure, still the only truly 
playable 1 6K Adventure! 



EACH GAME JUST 



I 

They swoop, they dodge, they 
loop figures of eight! Can you 
survive the Firebirds' attack? 
Amazing ht-res machine code 
action from the Masters, Any ZX 
Spectrum, By Graham Devine 



including VAT, Postage and 
UNCONDITIONAL GUARANTEE. 
ALL GAMES IN 100% MACHINE 
CODE. Available from all good 
shops, or if they are out of 
stock, direct from us by return of 
post - please make out your 
cheque/P-O. to Softek. 



3S9 Croxted 



K SOFTWARE 
Road, London SES4 



ZX SPECTRUM SOFTWARE 



(Continued from page 51} 
port art used to control the stepper motors; 
one bit is used to turn on and off the electro- 
magnet for the pen -up, pen-down mechanism, 
and two further bits are allocated to register 
the left and right collision switches. 

I was pleasantly surprised at how easy it was 
to write controlling software for the Buggy, 
Once I found out how to write to and read 
from the user port it did not take long to write 
a short program to steer the Buggy from the 
keyboard, detect collisions and operate the 
pen- 

Although the Buggy only runs go a BBC 
Micro at present, it should be possible to drive 
it from any micro with an eight-bit parallel 
port, Machines without analogue ports would 
be at a disadvantage and would require 
additional hardware to give the light sensors 
an on/off reading, Economatics is contem- 
plating adapting the Buggy for the two 
machines on the Dol's list of recommended 
micros for schools — the Spectrum and 
Research Machines 3SQZ, 

A robot can be described as an artificial 
intelligence in an artificial body. While the 
vehicle itself provides the body the BUG Micro 
or rather the programs it can run supply the 
intelligence. Along with the electronics and 
ironmongery almost 100K of software is 
supplied with the kit. The programs are 
graded and designed to take the user step by 
step up the artificial intelligence ladder. 

In the process ihey show how a computer 



can be used with a robot as a switching device, 
a memory, a graphics terminal, a pro- 
grammable device, an information processor 
and a problem solving unit. Since they 
demonstrate what the Buggy is capable of they 
are worth describing in some detail. 

Test, the first program, checks thai the 
Buggy is correctly set up and enables the user 
to test the sensors., displaying their input on 
the screen. This is followed by Switch, a short 
program, which lets you drive the Buggy in 
any direction by pressing the cursor keys. The 
vehicle is quick lo respond and can be readily 
steered hither and thither. 

As an advance on this facility Memory 
Switch records the key presses and can replay 
them in their sequence or in reverse order. 
This demonstrates how precisely the Buggy's 
movement can be controlled sending ihe 
Buggy along quite a complicated route several 
metres long and then commanding it to return, 



bringing it back to within a few centimetres of 
its starting position. 

Recorder draws a map on the screen oT the 
Buggy's progress while giving readouts of its 
position in an instrument panel below the 
map. Collisions are registered with a 
convincing crashing sound. Snail likewise 
plots the Buggy's path but also allows you to 
give it a coded sequence of instructions first, 
such as R30 or F50 meaning Turn Right 30 
degrees or Go Forward 50 centimetres. 

There are two programs which show how 
the Buggy can read in quite complex 
information from bar-codes. In Tin Pan Alley 
it reads musical information from a line of bar- 
codes, plays the tune and displays an animated 
score on the screen, Bar- Code Route Planner 





instructs the Buggy to follow route 
instructions given on bar-code cards, 

The remaining programs, in which the 
robot appears to act under its own control, 
demonstrate some of the principles of artificial 
intelligence. The Buggy is instructed to 
perform such tasks as seeking out an object 
and working out its size, following a black or 
white line, and measuring an enclosed area. 
Sunsccker programs the robot to track down a 
light source. 

Once it has located its goal it homes in 
negotiating any objects in its way. Man versus 
Buggy requires the user to perform the same 
i task — to drive the Buggy from the keyboard 
using ihc same information as is available to 
the computer which it presents on an 
instrument panel 

As soon as the vehicle starts to move in a 
purposeful manner it is difficult not to ascribe 
intelligence to its behaviour. One of the 
Buggy's predecessors, Dr Grey Walter's 
tortoise was a three-wheeled vehicle which 
could travel around a room avoiding obstacles. 
It was programmed to look for a power point 
to plug itself into and recharge its batteries 
when they ran low. Onlookers tended to feel 
empathy with it in its quest. The Buggy can 
provoke a similar response. It is bound to be a 
success in schools. 

The 13 programs in the software kit are 
written in Basic and the procedures they 
contain can be incorporated in the user's own 
programs, There is clearly scope for more 
advanced artificial intelligence applications. 

People who saw the Buggy on the BBC's 
Making the Mqh of the Miero scries will have 
seen it finding its way around a maze until it 
reached a light source at the end and then 
returned to the start. If the robot were fitted 
with a prab-arm it could for example be 
programmed to demonstrate the principles of 




the computerised warehouse. It would use the 
BCR to follow a line to a set of pigeon holes, 
then locate a pigeon hole which had been lit 
up, remove an item with a grab-arm, read its 
bar codes and use the information given to 
docket it elsewhere. 

A grab-arm is one of the hardware expan- 
sions Hconomatics is considering. Other 
possibilities could be in the form of extra 
sensors such as a proximity detccior or a heat 
detector. 

The MHP stresses that the robot should not 
be seen just as a toy. Hut the term toy need not 
be applied dismissively. After all for most 
owners' home computers have no practical 
application and could be described as adult 
toys. Whether or not everyone warns to build a 
robot, the idea of controlling a robot exerts a 
fascination for most people. The Buggy's 
inventor Mike Bos rock frankly describes it as 
"modern day Meccano," 

People ate not so much interested in the 
practical role of robots as uncomplaining 
drudges capable of performing menial tasks, as 
in their ability to carry out more complex and 
intricate routines. Linking the Buggy to the 
BBC Micro gives it considerable potential for 
such exercises in artificial intelligence. 

The MEP which developed the Buggy sees 
it as finding a place in both the home and 
school. Andrew Hopkins who has written the 
manual describes it as one solution to the 
problem of introducing more technology into 
the curriculum. Whatever its application ihc 
Buggy is certainly enjoyable to play with as 
well being a useful introduction to control 
technology and artificial intelligence. 



CONCLUSIONS 

■The Buggy may not be able to do the 
washing-up or the housework for 
you but it can provide an excellent 
introduction to robotics and control 
technology. 

■ A3 an educational device which has 

its place in many different pans of 
the curriculum the Buggy should be 
very popular. It is fun to use and easy 
to operate. Its low cost also puts it 
within the reach of home computer 
users who are interested in robots, 

■ The Buggy's capabilities are well 

demonstrated by the 13 programs 
which accompany it. These do not 
exhaust its possibilities and there is 
plenty of scope for a variety of more 
complicated applications, B 



YOUR COMPUTER. APRIL 1 983 &3 



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MICRO MANAGEMENT Apn 83 

Micro Management 32 Princes Street, Ipswich, Suffolk. Telephone: (0473) 59181 



™uft COMPUTER. APRIL 1383 SS 



TEN YEARS AFTER Tester drove Sinclair out of 
the pocket calculator market the TX-8000 is 
ready to take on the ZX-8 1 and the Spectrum, 
As with the calculators Te?fct hopes to win 
customers by aggressive pricing. But although 
the £98 TX-8000 is now the cheapest colour 
micro — by a whisker from the Oric and by 
£27 from the Spectrum — it has only 4K 
RAM as opposed to the 1oK of its rivals. 

The Z-80 based TX-8000 has a specification 
thai, on paper, looks very good compared with 
the ZX-&1. When it is compared with, for 
example, that of the Oric, then a number of 
weaknesses become apparent,. 

Of the three colour computers under £3 25 
- the Spectrum* Oric and TX-8000 — the 
TX-80QO is the largest. It case is made of a 
cream plastic* which feels more brittle than the 
plastic used for its rivals — but ii would still 
require an act ofmalice to break it. The design 
of the case is not as polished as that of its 
rivals, but it does have a gently sloping front 
which means the keys actually face the user. 

The dimensions of the case arc 12in. wide 
by 6in. deep, 2in. high at the rear and lin. 
high at the front. The parte! containing the 
keys is dark brown an J sunken into the body, 
There are 45 keys in a rubber keyboard which 
is very similar to that of the Spectrum, Not 
only do the keys squash down in the same way 
they even have that distinctive clammy feel to 
them, If anything the Texct keyboard feels 
worse than the Spectrum Y 

Individual keys are smaller than on the 
Spectrum, but there are more of them. 
Keyboard layout is based on the usual 
QWERTY typewriter formation, which the 
TX-8000 mimics better than the Spectrum. 
This necessitates fewer key depressions, 
especially in the case of punctuation symbols 
which can only be achieved by a shifted key on 
the Spectrum but have their usual typewriter 
keys on the TX-8000. 

Above the first eight number keys there are 
the corresponding colour names.; yellow, blue, 
red. buff, cyan, magenta* orange and green. 
This is the same colour set as on the Spectrum 
but with the addition of buff and orange. 
Interestingly, there is no black or white, which 
look in theory to be unobtainable. 

When using the keyboard the letter pressed 
is what appears on the scteen, even though 
certain Basic keywords are printed above and 
below the keys. The keywords are accessed by 
the kind of finger gymnastics that put me off 
the Spectrum when it first appeared. 
Alongside the keyboard is a power light which 
tells you when the machine is on* which 



£98 TEXET 
TX-8000 



sometimes is not apparent from looking at the 
strcen. 

On the right-hand side of the machine is a 
rocker-type switch, to turn the power on and 
ofF. This is a welcome feature, as anyone using 
a Spectrum or ZX-S1 will know that the 
continual insertion and removal of the power 
supply plug eventually works it loose. So a 
cold reset — that is a reset of the computer 
which clears the RAM — is a simple 
operation. 

Although the machine is marketed in this 
country as the Texet TX-8O00, elsewhere ii is 
known as the Video Technology VZ-200. This 
is taking badge engineering to new heights. 
The Texet is exactly the same as the Video 
Technology machine except for the VZ-200 
badge. Both machines are manufactured in 
Hong Kong* the factory-door price of the 
VZ-200 being S66 - less than £45. 

The real significance of this similarity is that 
there arc a number of interesting peripherals 
available for the VZ-200, which will work with 
the Tcxet. These include' 16K and 64K Ram 
extensions, joysticks, printer, light-pen, 
Modem, disc-drives and bar-code readers. 
There is also an interface unit which allows 
you to use any standard text or graphics 
printer. All these add-ons are manufactured by 
Video Technology in Hong Kong and will be 
available in the U.K. from Texet. Projected 
prices arc: printer, £129; 64K Ram expansion, 
£52* £3 for a single paddle and £60 for a pair 
of cordless remote control joysticks. 

Opening up the inside of the Texct is like 
digging in the garden of ihc Critiklewood 
house of horrors. A number of vaguely 
familiar objects are recognisable amongst the 
mess even though all the identifying codes on 
the chips have been painted out to preserve 
their anonymity. There is a black and white 
model of the VZ-200 in Hong Kong and one 
look inside the case of the Tcxet shows that it 
is basically a black and white computer that 



Wiffi intefmf ctrcukry thar looks tike this (below J if 1$ not surprising that colours are dispfaced b y half a 
character on screen. 



[ 




has been converted for colour. The colour 
circuitry is antique by the standards of the 
Oric or the Spectrum, with a large number of 
presets* pots, coils and resistors. 

On the rear of the machine are the usual 
power and TV output sockets. In addition 
there is a tape socket, which unlike 
conventional tape sockets is a stereo jack 
socket — the kind used on portable hi-fis. This 
connects to two mono jack plugs , red and 
black* the red one being the Ear connection 
and black the Mic. 

There is also a monitor output — which will 
not work with most monitors. Also along the 
back or the machine, but covered by a couple 
of aluminium panels arc the bus expanders. 
One is marked Memory Expansion and the 
other, Peripheral. This may imply that only 
one peripheral can be connected at a time. The 
panels are attached to the computer by two 
tiny screws. 

Power for the micro comes from a 
transformer which would plug straight into 
the power socket except thai it has a two^pin 
electric shaver-type plug. This needs a special 
adapter to enable it to be used with domestic 
U.K. power sockets. Unfortunately the pen- 
nies this adds to the price of the micro makes 
the Tcxet only a pound cheaper than the Oric, 

Because the transformer itself is attached to 
the plug its weight causes it lo work its way 
out of the socket. While this is not likely to be 
dangerous, due to the insulation on the pins, it 
does mean thai a programming session can be 
ruined and all work lost due the the resulting 
power failure. 

When the machine is powered up the 
message: VIDEO TECHNOLOGY 

BASIC VI. 
appears. The letters are in light green on a 
darker green background with the whole 
surrounded by a black border. The cursor — a 
square of light green,, flashes on and off. If the 
onfoff switch is flicked momentarily to the off 
position and back again a bizarre effect on 
screen is caused by the memory-mapped 
screen area of RAM being filled with garbage. 

The TX-8000 has only 4K RAM - and 2 K 
is available Tor programs, the other 2K is for 
the screen. The maximum size of a numeric 
array defined in a Basic DIM statement is 
1511 locations and a string array can hold 
1751 strings. 

Of course should you decide to use arrays 
that big, there will not be any room left for the 
program. Anyone who has used the ZX-8 1 
might think 2K is a lot of memory, especially 
when it does not have to store the display as 
well, If you w r ere a bit tight for space, you 
could try storing numbers as strings though. 



56 YOUR COMPUTER. Afftll. 1983 



~Vt_ 





18 colour 

computer reviewed by 

Bill Bennett. 



Arrays may be multidimensional, but 
warned, arrays of more than one dimension eat 1 
heavily into the memory. By the time you get 
to an array of seven dimensions, (2,2,2,2,2,2; 2), 
you have run out of memory. 

A simple line of Basic, such as; 
10 k=20 
only lakes up four bytes so a reasonable 
program can be squeezed into the memory. 
However this compares very unfavourably 
with the Oric, which is only a fraction more 
expensive, but has a nominal JGK of RAM, 

The organisation of the video memory is 
interesting, in the normal text mode — which 
is called from Basic by the command Mode(0}, 
the first 512 bytes of video memory store the 



ASCII codes of 
screen characters. 

Any of the machine's 
character set of 255 characters 
can be Poked into this memory, 
and of course it is the area that the 
Print command uses. 

All the usual characters appear in the set, 
together with their inverses. In addition there 
is i subset of graphic characters which consist 



of the character 
square divided 
into four smaller 
squares, filled in ah 
possible combinations. 
This graphic subset is 
repeated four times. 
When the machine is 
initially turned on this 
character set appears in four 
different colours but use of the 
Color command — which is 
similar to Ink on the Spectrum — 
changes this, and the four sets seem 
to change to arbitary colours. 

fcontmyGfj On page 59/ 



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(continued from page S7t 

Color only affects the gTaphic symbols. 
There is no provision for priming words or 
letters in colour. What is strange is 3 lack of 
black or white on she screen. In practice the 
colour designated as Buff is slightly off-white 
and for most purposes can be used in its place, 
Black can be obtained only as the other colour 
in the graphic symbol character set. 

There is a major problem with the colour on 
the Texet, it seems that each of the colours is 
attributed to a character space that is displaced 
half a character to the right of the printed 
character. That is, the printed characters and 
their assigned colours do not match up on the 
screen. This could be a fault in the review 
machine, but looking at the colour circuitry 
within it is not surprising. 

It is a shame about the colour location 
problem, because the colours themselves are 
the brightest on any of the cheaper colour 
computers. The red is a little darker than it 
should be, but the blue and orange are as 
luminous as Day-Glo colours. The colours can 
be changed by altering the controls of your 

TV sctj but the alignment problem cannot be 

ironed out. 

The graphics characters can be printed or 
Poked on to the screen by using their character 
codes, but they are also accessible from the 
keyboard- To print them in, say, a pair of 
quotes inside a Print statement, you have to 
press both shift and control at once, then the 
relevant graphics key. Graphics are printed on 
the key switches, so you have some idea which 
one you are using. On the Z key a graphic 
block is printed which does not cur respond in 
the character printed by that key, and keys: x, 
e, v, b, are merely repeats of characters that 
can be found elsewhere and consequently are 
not marked. 

When printed directly from the keyboard 
the graphics characters appear in the default 
light and dark green colour set, After a Color 
command however they will be printed on the 
screen in thai colour. The characters print 
on to the screen extremely fast in this mode, a 
thousand colour graphic strings taking less 
than 20 seconds. But there is a price to pay. A 
string can only contain graphic characters of 
one colour, and that colour is always the 
colour specified by the preceding Color 
command. 

In the text graphics mode, mode 0, the 
screen is organised into 16 lines of J2 
characters. This compares with 24 lines of J2 
on the Spectrum — or more correctly 22 
usable lines, and 28 by AH on the Oric — 
which is a Prestel-like display- 



High -Resolution mode, mode I, is not really 
high-resolution at all. There arc only 128 by 
61 pixel locations, which is not much better 
than some — albeit much more expensive — 
microcomputers 1 text mode. This take* up the 
entire 2K of the video memory, which is 
interesting because 128 * 64 is not 2K, but 
SK. 

It works in a way that is similar to the text 
mode. There are 32 columns and 64 rows, 
each of which can have any value up to the 
eight-bit limit of 255. In text mode these 
normally represent characters, but in mode 1 
they represent short graphic strings of four 
pixels, arranged in a line one after the other. 
Poking a value into one of these locations 
specifies the colour of each of those four 
pixels. 

Obviously not all possible combinations of 
the eight colours in four pixels can be 
accommodated — there are 4,000. Unfortun- 
ately thanks to the colour misalignment, 
colour is not always visible in this mode. 

Light green is the only possible background 



CONCLUSIONS 

■The Texet TX-8000 may enjoy a brief 
period of fame as the cheapest cotour 
computer around but too many com- 
promises have been made. 

■The colour display on the screen 
needs tidying up as does the internal 
construction of the Texet- If this was 
done then the peripherals available 
for the TX-8000 especially 64K 
expansion for £52 might make it 
worth a second glance. 

■The shortcomings of the E98 Texet 
make the high standards of the £99 
Oric and the E125 Spectrum seem all 
the more remarkable. 



allowed in the so-called high- resolution mode, 
To let you know that the mode has changed 
from low- resolution/text to the pseudo high- 
resolution the border colour changes from soot 
black to the same lime green as the ress of the 
screen. This is to avoid any confusion between 
what might be called low-resolution 1 and low- 
resolution 2. 

So bad is the colour misalignment that when 
a sine curve is displayed on the screen, it 
appears as black on the lime green back- 
ground, with a hint of whatever the chosen 
colour was around the edges. This makes a 
mockery of the TX-8000's ability to display 
any of its eight colours at any one of the 128 
by 64 locations. 

Poking to the display is a com plicated 



business in this mode, so there are adequate 
Basic commands to handle the graphics. They 
are Set and Reset — which plot and unplot 
points on the screen, and Point which 
examines a position and tells vou if it is on or 
Off. 

Despite the ventilation both in the top of 
and under the case, the machine can become 
very hot. This could be due to the poor 
thermal contact of the heat sink, which was 
only loosely connected to the power supply 
semiconductor. This can cause problems. 
When the machine was turned off momen- 
tarily — due to the transformer falling out of 
the socket — the television had to be retimed 
to obtain a picture. 

TX-8000 Basic is a fairly standard version of 
Microsoft Basic. It holds few surprises but 
does have some refinements that, if omitted, 
would make the Texet a very old-fashioned 
machine indeed. There is the Step to go with 
For , . Next, and the Ehe to supplement the If 
. . Then. As far as structures go, the TX-8000 
is a non-starter, 

Cassettes are loaded with the CLoad com- 
mand, which causes the machine to print Bad 
on the screen whenever a load fails. Loading is 
extremely difficult because unlike the 
Spectrum there is no screen display to let you 
know how well the load is going. 

CSave is accompanied by a Verify command, 
which no self-respecting micro would be seen 
without these days. All the tape operations are 
performed at 600 baud which is faster than the 
ZX-SI but slower than the Spectrum — the 
Oric allows you to choose speeds. The speed 
could be at the root of the loading problems 
but more likely the main offender is the power 
socket, which is located right next to the 
cassette socket - 

Baste programming lines cannot be longer 
than two screen lines. If you try entering one 
longer you simply lose it without warning. 
The Sound command is feeble compared to the 
Oric All n can do ;s play rarhci quiet tones 
there is no loudspeaker. The Sound command 
has two parameters, the first being the pitch. 
This can have any integer value between I and 
31. If a decimal number is input it simply 
truncates and plays the next one down. The 
second parameter is the length of the tone and 
this *S Variable between one and nine. 

Numbers can only be printed to six 
significant figures which means that should a 
business be in such bad shape that it decides to 
install a TX-8000 as a computer, it will never 
be able process debts greater than £9,999.99. 
To ensure neatness trailing zeros art 
suppressed. 





Youft coMPuren, apsi. 1933 59 



- 




FOR THE 



MEMORY 

3-5K • 




Hkrk is an implementation of Snake for the 
Vic-20. Although in Basic, if is fast and 
addictive, and makes good use of defined and 
multicoloured graphics. The game, admittedly 
inspired by the veritable plague of ZX Snakes 
in February's Software File, just squeezes into 
the basic machine. Littk space is left for 
instructions so do not enter line ID. 

Using the S, X, < and > keys you steer the 
head of a snake. When you first Run the 
program, you get five seconds grace before the 
snake automatically moves down the screen. 

The object is to clear the screen of flics and 
beetle!.. Watch out for the mushrooms though 
— they are poisonous. Both beetles and [ties 
make the snake grow, but flies more so than 
beetles. The flies also Score more. The more 
you eat, the faster the snake moves. 

If you run into yourself, being a prisonous 
snake, you will die. One other snag — if you 
run into the surrounding fence, or try to move 
alongside yourself, you will find the snake 
stops, and your score decreases rapidly. And if 
your score ever gets below zero, the Vic 
assumes you have committed suicide. This is 
why you can only move left or down at the 
start. You could also find yourself boxed in. 

Swarm of insects 

If you manage to clear the screen, another 
swarm of insects descends, although the snake 
stays the same length, and a batch of 10 extra 
mushrooms grow. The game therefore grows 
progressively harder. 

When the game is over, if you are in the top 
five scores, you can enter your initials in the 
Hall of Fame. 

This program is a perfect illustration of how 
straightforward programming coupled with 
the Vic's excellent graphics and sound 
capabilities can produce a good enjoyable 
game. 

Here is a breakdown of the program: lines 
20-100 initialise it and line 50 lowers RAMtop 

«0 YGUflCOMPjrEH, APRIL 1983 



to protect defined graphics. The fixed 
graphics characters start at line 60. 

S = Segment of snake 

M = Mushroom 

B = Beetle 

F - Fly 

W ■■ Wall 
At line 100, NM sets the initial number of 
mushrooms, and Poke V,47 sets the auxiliary 
colour for ihc defined graphics used in the 
program . 

Lines 120-140 set up the starting position of 
the snake's head — HP — and tail — TP — 
and display it as well as setting its starting 
direction D and its head character H. Lines 
170-190 wait five seconds for a key to be 
pressed and then continue Lines 210-250 
work out the snake's new direction, depending 
on which key was pressed, and from that work 



THESE ARE SOME OF THE 
COLOUR AND CURSOR CONTROL 
CHARACTERS USEB IN THE 
PROGRAM 



FOR "i 
<CTRL 

"■" - 

ii j _ 

ii ^n _ 

"«" - 

"ST - 

"S" - 



r READ INVERSE POUND 
+ KEV 5> 

SLACK (CTRL + KEV 1> 
WHITE <CTRL + KEV 2> 
CYAN (CTRL + KEV 4> 
GREEN uCTRL + KEV 6> 



VELLUW (CTRL + KEV 8> 

REVERSE ON 

<CTRL + KEV 9) 

REVERSE OFF 

CURSOR D0NN 

CURSOR HONE 

CLR 

CURSOR RIGHT 
II" ■ CURSOR LEFT 
USE KEVS S AND H FOR UP 
AND DOWN 

USE KEVS < AND > FOR LEFT 
NNU RIGHT 



U JQII 

II "111 

"IP 

Ii 



out the character to be used for the snake's 
head. 

All the checks on where the snake is are 
contained in lines 280-310, These lines also 
verify thai the move is allowed, and branch to 
the appropriate part of the program if 
necessary. 

Line 320 checks if all the beetles and Ylics 
have been eaten, and if they have, displays 
some more. This line also adds 10 more 
mushrooms. This is the end of the main loop. 

Move-snake routine 

The move-snake routine is at lines 500-570. 
It does this by simply moving the snakes head 
forward and erasing the tail. If the extra-length 
— EL — variable is greater than Z£to t it 
subtracts one from it and skips the erase tail 
section. 

After it has erased the tail, it then looks for a 
segment next to it, which becomes the new 
tail. Incidentally, this is the reason why there 
must always be at least one character between 
"folds" of the snake as it twists and turns. 
Oiherwise it could confuse this part of the 
program. 

Lines 700-740 and 750-790 arc the routines 
called when either a beetle or a fly is hit. They 
increase the score and the "extra length" 
counter. 

Lines 800-8:30 are called when the snake 
either runs into the wall or tries to move 
alongside itself. 

The score is converted into a six-character 
string and displayed at Hues 900-920. 

Lines 1000-1200 define the graphics used in 
the game, and lines 1500-1590 set up the 
screen display for the game. The lines starting 
at I5o0 display the mushroom, beetles and 
flies. Lines 2000-2200 are the "game over" 
part. The length of the 

FOR 1 = 1 TO , . . NEXT 
delay in line 2000 produces an interesting 
strobe effect. 



VIC-20 

A python can swallow a 

sheep but this economical 

program by Andrew Dilley 

will not put any bulges in 

your Vic-20. If you're 

partial to flies and beetles, 

this is the game for you — 

but take our advice and lay 

off the mushrooms. 




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DOT 0209 

369 IFP=BTH£NGQSUB708 

310 IFP-FTHENOOSUB7S0 

320 IFMB-aftNpMF=0THEHNI1"lB GOSUBI360 G0T01~a 

J30 GOS-UtSOO GOT 0205 

5@0 POKES 1,170 

510 POKEHP+CO, 13 POKE HP, & HP-NP P0KEHP+CO, 1 POKErt^-H 

529 IF£L>0THENEL-EL-1 GOTO550 

538 P0KETP,22 

540 TP^rP-vPEEKCTP+l?*S>+<PEEK<TP-l>'S>+22*<PEEKCTP-22^S>-22*<PEEK'rP*22J=S> 

550 POKES 1-0 

560 FORT* 1TQ156-4*L : NEXT 

S70 RETURH 

780 PiQKESR-li L = L-1 EL=EL*1 

?lii >^lNTitlOO+S*LV10> 

720 FORI^nOlfc POKE$2,200 P0KEltfM*J28 

730 SC»SC+X G0SUB999 PCkES2,0 NEXT :POKESR, 10= HB-NB-1 POKES**, 32 

740 RETURH 

?S0 POKESR, 14 i L-L+2 EL-EL+2 



769 X=INT<<l58+6#LVie> 

770 FOffI = iTOf0 PCIKE$2.220 POKENP, 1+123 

780 SC-SC+X GOSUB90O POKES2,0 NEXT:P0KESR, t9 NF*HF-1 FOKENP,32 
790 RETURH 
S00 P0KES2, 188 
310 5C^SC-10 OOSUB300 
826 P0KES20 
530 RETURH 
800 8*=8TR*<SC> O=LENCS#);St-LEFT*( ,, e0008 , >7-O>+RIGHTf<S*,(KI> 

9te print "h^mhsts* 

920 RETURN 

I M0 FORC-35T04S : FORZ=0TO7 PERDU RQKE7l6S+S*C+2, H NEXT NEXT 

1010 F0RZ*8*32TD8» 32+7 POKE716B+Z,0 NEXT 

1D20 RETURH 

J ISO DRTR255, 171 , 1 71, f 39, 171 , 17! , 171 ,255,255- 136^ 187, 139,235,235, 136,255 

1120 BRTA255, 136, 170,168,170,170, 138,255,255- 143, 191,159,191, 191,143,255 

1140 DATR56, 124.124,254-186-56,56,124, 130,84,56,254,56,254,56,254 

1160 LflTfiies, 16,124 , 136, 1S6, 186,94- 16,40,40, 190, 190, 190, 190,40,40 

1180 DRTR43, 104, 1 09. 254, 254, 109> 104,48, J 2, 22, 182,12?, 127, 132,22,12 

1200 [1*7*36,24-60. 126, 1 53, 235, 126, 24, 24, 126, 255- 133- 125, 60, 24, 36 

1500 P0KE36S69,£55 

1510 P0KESR . 10-PRlHT , -3»tX«3|r *Tfl8( 1 !.>"■»*«*«■ " 

1529 FORJ-OT021 Pl^TC+22+IP2=TC+22*22+I P3^TC+22*<l+lJP4*TC+2l+£2*(I+n 
1 538 POKEP 1 , H POK EP2 ■ U P0KEP3 - U P0KEP4 , U P0KEP 1 *C0 - 5 POKEP2+C0, 5 : P0KEP3+CC , 3 ; PO 
EP4+C05 
1550 NEXT 

1 560 C H-H C-4 N=NM G0$UB J 700 
1570 CH-&OSNfr*l5 N-NB GOSUB170O 

1530 CH=FC=? UF-5 N-NF G0SUB179© 
1530 RETURH 
1700 FORI- 1 TON 

L7L0 P-TC +FNRX20 > ♦ 1 +22*<FNR< 191 +3 > 
1720 IFPEEK<PK>32THEHI710 
1730 POKEP+CO,C PQKEPCH 
1740 NEXT 
1750 
2000 



Pi 



. -<j FORT-1TO250 PUK!ESR,2 FORI-1TO10:H£XT'POKE5R, 10 NEXT 

2050 F0ftV0"15TOOSTEP-,l POKEV.VQ NEXT 

I 068 POKE ." , 8 PQKESft, 1 2 : P0KE36869 , 240 POKE 1 98 , & 

2070 PRINT "num KILLED BV A PERDLV PRiNT'liiSM POISONED HUSWIOOM " 

1Vi£:m K=0 FORI = 1T05 I-:-' -.■> <L- <_£" : r • F I ■ J ■ ■ '■ THEMM [«5 

2090 NEXT IFK=OTNENFORT=1TO1000 : HE:-:T GuTO2150 

2190 PRINT-'I^VOU HRE OJ*E OF THE TOP FIVE PLfi-VERS" 

2110 PRIHT"»ENT£R VOL* INITIftLSJB" IflPUtl t IFLE-Mi I J >';. 2THEH2H0 

2120 F0ftl»4T0KSTEP-l E*< 1+1 >*B*U J TiEl-T 

2138 E*0,,i=S*+" "+I* 

2150 PQKE5R,7& FRINT"XT«B<5>"**LL OF FRME M 

2160 F0Rl'=lTO5'PRlNT-jM"J ,, T , |:*<n HEXT 

2170 PRlNT-waiRHOrHER GO<V/H;W N [NPUTV* 

2180 IFV*-"VTH£N100 

2198 lFV*» N N"THENPRlHT-JtfTH«tttt8 FOR PLRVIMG" Etil* 

2200 GOTO2170 

;*0O POJiESR, 154 PRINT TUB S 

J02O PR1HT"S USE THEiE KEYS " 

i©30 PRINT J, p;p*i»lllF rl(ian3»WI-EFT-i< ; *-PIGHTJ!*i*iHi :'lll I rlllE! <:i- 

3040 PRIUT-JSW EFlT THE FLIES ft" ■PRJNT ,, » BEETLE& - EJT EEWHPE" 

3650 PR I NT "W THE DEAOLV N(J5■HPCl0^t$■ , " 

:^O60 GosuEiee* 

307O PRINT" 1 :*!!* hIT RNV KEV TO START', 

3080 OETFl* lFAf=" 'THEH30SO 

309O RETURN 



NflKE" BVTE 




V0U8 COMPUTER, APRH 1983 6l 



BBC 
MICRO 
INSTANT 
MACHINE 



C 



• II 



E! 



Yes, it's true. Instant machine code from a good 
subset of BBC BASIC. Type your BASIC program 
into your mode! B BBC Micro, trigger the 
compiler, and your program is changed almost 
instantaneously into superfast machine code. 
For £34.95 you get: Cassette version of the 
complete compiler (along with a version of the 
compiler for use with discs, ready for when you 
upgrade, the disc version being dubbed on the 
cassette after the cassette version), complete 
compiler listing; extensive documentation and 
instructions. The compiler was written by Jeremy 
Ruston, 

THE BBC MICRO 
REVEALED 

By Jeremy Ruston 

'. . .destmed to become The bible of all BBC microcomputer 
users. . .'{Personal Computing TodayMI you've mastered the 
manual, then this book is for you. Just £7.95 

LET YOUR BBC MICRO TEACH YOU TO 
PROGRAM 

By Tim Hartnell 

'. , .takes you further into the doudy areas of the BBC machine 
than anything else I've yet seer>. , .' {Computer and Video 
Games}. If you're just starting out in the world of programm- 
ing, then this book is the one for you- Forty complete 
programs, Including Othello/Reverse Piano end a host of 
dramatic graphic demos. Just £6.45 

Interface, Dept.VC 

44-4* Carls Court Road, London We fiEJ 

Please tend me: 

( ) INSTANT BBC MACHINE CODE-tap* and book-£34.96 

( , THE BBC MICRO REVEALED-Ru*ton-£J,95 

I ) LET YOUR HBC MICRO TEACH YOU TO PROGRAM - 
Hert»e4l-£&46 

I enclose £ 

Name ,...,.,. ., , .,„„„„«„,..„.„....■„-...,„...... 



SPECTRUM 







"■■•>■„ 



Make the most of your Spectrum, with these 
acclaimed books from the experts! 

PROGRAMMING YOUR 
ZX SPECTRUM 

Tim Hartnell and Dilwyn Jones 



More than 100 routines and programs, 230 pages, and value 
for every Spectrum user. Learn how to make the most of 
user-defined graphics (with a Pacman-Nke program. 
DOTMANI; sound, colour, and such commands as ATTR, 
SCREENS and BRIGHT. From the co -ordinal or of the National 
ZX Users' Club, Tim Hartnell. Just £6.95- 



THE SPECTRUM 
SOFTWARE LIBRARY 

60 GAMES AMD APPLICATIONS FOR THE 
ZX SPECTRUM! 

By David Harwood 



Arcade games, intelligent board games, brain games and 
utility programs. They're all here in this massive collection of 
60 tested programs for the Spectrum, compiled by Interface 
columnist David Harwood. Just £4.95. 



interface, 
Dept.YC 

44-46 Earls Court Road. London, WU GEJ 
Please send me: 

{ I PROG RAM MING YOU R ZX S PECTRU M - E6.95 

( } THE SPECTRUM SOFTWARE U9RARY-£4.&5 

( | A sample issue of INTERFACE, the monthly magazine 
published by the National ZX Users' Club- £1.00 

I enclose £ 

Name „ ..,.,„„ * 

Address 



62 YOUR COMPUTER. APRIL 1983 




MiORG SHC 



ZX8I-ZX SPECTRUM 



DRAGON 52 



ZO-BBC 



The very best mail order items available 
"over the counter" 

Games, Keyboards, Serious Programs, Rams, 
Books, Peripherals and much, much more! 



FAST MAIL ORDER SERVICE PHONE 01-769 2887 

WITH ACCESS/ VISA (24hr Ansafone} 

or send large S.A.E. for catalogue (state which computer) 



Open 10 30 - 5,30 lues, to Sat. (closed Mondays) 
310 STREATHAM HIGH ROAD, LONDON SWIG 




BRINGS YOU 
THE PICK OF THE 

GAMES! 

GAMES- GAMES- GAM ESI More and more computer games hit 
the market every month, BUT THEY CAN" TALL BE GOOD. So- let 
LEISUREMAfL snort JfsT the VERY BEST for you Send 50p NOW for 
our big BEST OF THE BUNCH" catalogue. We select TOP 
QUALITY SOFTWARE FOR YOUR ZX8I - SPECTRUM - BBC 
MICRO - GEME 2 - VIC 20 - DRAGON 32 - ATARI etc, 

SPECIAL THIS MONTH 

New Generation ESCAPE for 16K Spectrum - voted by Sinclair 
User as best and most original game yet seen for Spectrum! Only 
£4,95 post paid. Simply amajing graphics. Also fabulous new 
release -3D TUNNEL- S6K and 48 K versions for Spectrum on one 
tape -ES 95 

To:-LEISUREMAJLfYCl, 69, Long Lane, London EC1A9EJ. 



Please rustl me your BUMPER CATALOGUE of TOP FLIGHT 
GAMES. I enclose SOp (refundable first order). 

1 endose£ for. . , .ESCAPE and/ or 3DTUNNEL, plus 

free catalogue- OR debit my ACCESS/DINE RS/AMEX 
account number ...... 

Name:- *. ,.„....., 

Address;- . 



DONT MISS THIS 
INCREDIBLE OFFER ! 



50 GAMES 



IH £9 95 







=£*» 



SO GA. MESi on tassei ic tbrall 

ihefolJowing* 



&*. *£ riC ATTACK 

p Act JUUVW 

.U'i»* LA*(?<N 
ri A'l'.CA »0: T 

trAjrracx 

4*;** LAM -id 

J-TTACttJi 
i*V*C*l«IM»'lSJtT 
~tW>4 * *1 AC" 

OXCt 

WXALEa 
HJhTQOft 
'.< i j . '■■ I" 
MMlCWA*. 
01 B tCWS 

*rt.t. Ci 



MA/t |AT(« 

until Ha 

U0T4R**f 

fanci fiflD 

t. N 

TUWaii i«A»i 

uadtL Jl'Vi 



• kACKMOlI 

■muinri 
do«a MttUM 

0i»B*DA5H 



CAtUtOMA^UfTLL fPAd kjuch 



ti.-ffi'AKf 

S**CE in* 
CTfLlUHl 

mil" 

i»fnu5t« 
i«f f HHC 

G>J£HTi 



„"slvE*Si 

A0.TS 

TAtttCM 

MJI AtHUTf 

JETWMiLF 

hHjHHIK 




PCS MCf PffEF TO U.K. 
ORDER Of RECT TO.- 

u.t.s. 

P.O. Box 96 

HAftftQGATE 

MOUTH YORKSHIRE 

HG3 2UZ 



SPECTRUM 

■^ I :oftiasc* 

^BCIPPIG C*SSEtT*> 

A.CURN-ATOM 

BLUB 

DRAGON 
ATJXRt VIC 51 
SHARP 

ORIC-1 

VFM/Hff4f/V 
ZJT8/ LVAVX 



PLEASE St NO ME 

CHEQUE E SSCLDSE D, VAL ; II 

NAMF __ 

ADDH ESS . 

POSTCODE 



**Si 



«#£& 



GI72* 



now 



-J 



TI99/4A ^V*k DF « AG N 32 

QUALITY SOFTWARE AT SENSIBLE PRICES 

DRAGON 32 

Order 

eode Tlile Price 

DG2 C*t«p>ll9i * Spate Afiack , £2.95 

DG8 Aicade Action CMetec? Run * Breakout) £3.95 

DG4 Hauniec House „.„......,„...... £3.95 

□G6 Forbidden City (acfvcnluro) „....., £4-95 

DGiO Dev s Wane {sKiwiljrej £4.95 

□ G1 1 Goblin Caves ',3-0 g'apfucs) ,,.,.., ,....,,..... £4.95 

DG1 2 G<* {rst.rf* graphics] £fl-95 

TEXAS TI99/4A 

GWS HBLif>t$d t-k>usft * Wumpus £3.95 

GM6 Sorcerers Castle + lunar Lander £3.95 

GW7 3-D Maie * Towers d Hanoi , £3.95 

G^17 Foibideen City - Mastermind . , £4.95 

GM18 Pharaoi's Curse * 3D Os & Xs £4.95 

GVt9 Devi's isJano • Russian Roulette., £4.95 

GM20 Gobin Caves • Anag*afn.. £4.95 

GM21 Cialiceor Kalrnar * Penguin , , £3.95 

All prices include VAT Pluase add 5Qf> p&p lo alt ordeis undef CIS Ov«f E6 
post free. Send cheque. P.O or tetephone win Aetc$$, aarcfaytsfd tot 
immediaie despaich Seno sae. Iw compieife iisi staling machine 

APEX TRADING LTD 

115 Crescent Drive South 

Brighton BN2 6SB 

Tel: (0273) 36894 

DEALER ENQUIRIES WELCOME 





YOUR COM PUT £H . APRIL 1963 63 



10 TIKER-0 

20 GOTO320:CLS 

30 ft 1=0 

40 CLS:p=105S!Q^RNDC7)+l 

50 FORI-0TO62:SETCI*ftl*Q) :NEXT 

£0 FDRI^0TD31 iSETC <A1 *2> -CA1=31 ),I,QJ s NEXT: IFA1=31 

THENS0 
70 A1*31:GOTD50 

S0 L = l i38:C=0:B=l : P=0: T=0*. Y=4S: X~TIMER 
90 Z=INT(RND<44S) ) +A+32 
100 IFZ=L-B ORPEEK'.'Z) O 96 THEN90 
110 Y^Y+l:PQKEZ- Y 
120 ' 

130 A*=aNKEY*UFA*="M" Dim***"!" THEN270 
140 K-PEEKCL+B) 5IFK0 96 THEN 170 
150 POKEL, 96 

160 L=L+B:POKEL, 79:GOTO130 
170 IF TIMER-X>3600 THEN490 
180 1FK=Y GRK)1UTHEN230 
190 C=SGNCB)*C33-ABS<:B>> 
200 Z=87:IFK^lil THENC=-d Z=43 
210 SOUNDZ, 1 : IFPEEKCL+B+C) <) 96 THEN150 

220 POKEL I 36:L=L+B:B^C!BDTD160 lp##&;#:#^^ 

230 1FK=Y THEN250 
240 B=-6:SQUND61, 1=GQTQ150 
250 Z=225:FORJ-1TO9:SDUND390-Zt I I NEXT 
260 T=T+l:GOTO90 

270 C=SGI\KB)*<:33-fiB5<B>) V X "^^S^:^:^^* v * 

2S0 Z=7S:IFfi*="Z" THENC=-C: Z=3B 
290 IFPEEKCL+C) O 96 THEN 150 
300 POKEL, 111 + 0;A*="M">*19> :SOUNDZ, 1 
310 P=P+1:B-C;GOTO160 
320 CL5: FR I NT3 172, "REBOUND" 
330 GOSUB600 

340 PRINT: PRINT" THE ULTIMATE GAME OF SKILL" : GQSUB600 
350 CLS:PRINT" YOU HAVE ONE MINUTE TO HIT AS"," MANY TARGETS AS 
YOU CAN BY 




360 PRINT" PLACING PADDLES IN THE PATH OF' 



THE BALL. 



370 PRINT: PRINT" PRESSING 'Z' GIVES YOU ' /' 

330 PRINT" 'M' GIVES YOU POKE 1242, 92 

330 PRINT:PRINT" IF YOU USE TOO MANY PADDLES "," YOUR SCORE WILL BE 
REDUCED. " 

400 PRINT345E, "PRESS ANY KEY" 

410 GO5UB610 

420 CLS:PRINT" YOU WILL NOT BE ABLE TO HIT ",,," TARGETS WHEN VERY 

CLOSE AND 
430 PRINT: PRINT*' UNWANTED PADDLES AND TARGETS '■,,,■' MAY BE ERASED" 
440 PRINT: PRINT" TO PLAY: -*' , , , , " SELECT * A* FOR AMATEUR",,," 

' P T FOR PROFESSIONAL 
450 PRINTJPRINT" ' N' TO END 

460 GOSUB510: IFA*<> "A" ORA$ O "P"THENGQSUB610 
470 IFA*="P" THENPDKE65495, 0:GOTO30 
480 IFA$="A" THEN30 

DRA3C^ 



64 YOUR COMPUTER. APRIL 1933 




GAMES 



You'll have to be fast off 
the mark to master 
Vincent Crockett's original 
game for the Dragon 32, 
Your quick reflexes come 
into play as you set the 
paddles which will send 
the ball racing towards a 
new high score. Your 
targets are the randomly- 
generated numbers that 
appear scattered over the 
screen. Full instructions 
are included in the 
program itself. Because 
Rebound uses Poke 
locations to increase speed 
of play, you must finish 
each game properly and 
not just stop using the 
Break key. Remember: you 
have only one minute per 
game and if you use too 
many paddles, your score 
will be reduced. 



490 
500 
510 
520 
530 
540 
550 
560 
570 



5S0 
530 
600 
610 
620 
630 



FORZ-250TO4 STEP-EsSOUNDZ, 1:MEXT 

P0KEG5494, 

PR I NTS 108* "GAME OVER"? 

DOSUBG00 

CLSi PRINT339, "YOU HIT" ST? "TARGETS 

PRINTS 102, "YOU USED" ?P;' 4 PADDLES 

5=INTCe000*T/CP+70) )/10 

PRINT316S, "YOUR SCORE IS";S;">1" 

IFS>HS THENHS-SsZ=200:FORJ=tTO9:Z=350-Z:SDUNDZ, 1 

PRINT3224:PRINT3234, " its a record" ;FOR£l =1TO30J 

NEXT:NEXT 

PRINT: PRINT" HIGH SCORE IS" ; HS; " %" 

GOSUBE00 : GQTO440 

FDRI=1 TO2000: NEXT : RETURN 

A*=INK£Y$: IFR*=" "THENE10 

IFA*="N H THENEND 

RETURN 




REBOUND 



YOUR COMPUTER APHH. 1983 65 




ON r E OF THE dreams thai accompanies mow 
micros into the home is the vision of massive 
information storage. Within weeks, every 
recipe will be stored, every cheque and bill 
recorded, phone numbers available at the mere 
touch of a button. Even if (he dream does not 
turn into a nightmare, it usually fades for two 
reasons: first, for a great many purposes, the 
amount of benefit to be gained from putting 
information on to a micro simply docs not 
justify the amount of work needed to program 
it in or to retrieve it; and secondly, large 
masses of information have a nasty habit of 
resisting all attempts to process them or 
present them in an orderly fashion — it is all 
very well storing the whole of the telephone 
directory on your micro but how do you 
actually persuade the thing to tell you what 
you want to know? 

The program accompanying this article is 
directed at 16K. ZX-81 Owners who have 
decided that they do want to use their 
machines for information storage and retrieval 
but have run up against problems in practice. 
The system is called Unifile and it is, 
basically, an empty filing cabinet waiting to be 
filled with information which it will arrange 
according to instructions laid down by the 
user and } equally important, retrieve and 
display information or amend it. 

The Unifile program stores its dara in a 
single string which can be as long as The 
memory of your expanded ZX-81 will allow. 
This is not The simplest method of storage by 
any means. Imagine, for instance, a file 
consisting only of 100 names. By far The 
simplest way to store them on a ZX-81 would 
be to use a string array — each name would be 
in a clearly definable place and to gain access 
to any name you would have only to specify its 
number in the array, a fast and uncomplicated 
technique. 

The real problem is one of space. It is 
unlikely that you will have many names with 
20 characters in them, but if your filing system 
is not 10 break down the firsi lime you come 
across such a name, your array must allow for 
at least 20 charades — a 100 by 20 array. The 
result is that every time you enter "Smith, J 
H" you have wasted an enormous amount of 
space in your memory because even with the 
punctuation you only needed 10 characters of 
the 20 you have set aside in the array. 

If all you have to worry about is one 
hundred, or even two or three hundred names, 
then do put them into an array. But what if 
you wish to add details to the names, so that 
for each name entered into the file there may 
be five or six Other items of informal ion, all of 
which will require a space allocation in the 
array, Space enough in the memory for three 
hundred names now becomes space enough 
for only 50 names with their attendant details, 



assuming that you allow a possible di) 
characters for each item of information. 

li is for this reason thai most computer- 
filing systems use a storage method which 
allocates to each item of information only as 
much space as it actually needs and on the 
2X-8 I the only way io achieve this end is to 
pack each item into a siring. The technique 
raises its own problems, as the following 
example will illustrate. 
Name: Smiih 
C/name; John 
Address: 12 North St 
Town: AnyTOwn 
Phone: 0998-11111 
Age: 35 

interests: ferret washing 
This is a typical entry from an imaginary file 
and is fairly self-explanatory. Packed into a 
siring, however, si becomes slightly less clear; 
SMlf HJOHN12 NORTH STANYTQWN 
099& 1 11 11 35FE R RET WASH I NG 
It may still be decipherable to the human eye, 
but how is a program searching a string made 
up of many such entries, packed together, to 
know where one item begins and anoTher ends. 
It would be much clearer if we marked each 
item, at the cos! of very little extra space: 
+ SMITH ■JOHN* 12 NORTH ST'ANYTOWN* 
0998-111 n-35*FERRET WASHING + 
We can now instruct our program, when it 
searches for a particular item, to recognise a 
plus sign as the beginning of an entry and an 
asterisk as marking individual items within 
that entry. Unfortunately such separator 
symbols can only be recognised if the string of 
information is examined character by 
character, which is fine when you are dealing 
with only a few entries but a little on the slow 
side if your file has grown to around 10,000 
characters. 

Some method is needed which allows the 
program to identify the beginning and end of 
an entry without examining every character in 
ihe file. The Unifile program achieves this by 
attaching to each entry a special indicator 
called a "string length indicator 1 ', or SLI. 

In the case of a small system such as Unifile, 
the SLI does nor need to be able to cope with 
huge entries and it is, in fact, one character 
whose Code value is the length of the whole 
entry. 

This limits The length of each entry to 255 
characters, or approximately five times as 
much information as was stored in our 
specimen entry, which has been found in 
practice to be adequate. 

While the Unifile program cannot jump to 
the middle of its stored data and unerringly 
identify the beginning of an entry, using the 
SLls it can quickly scan along its files, 
jumping from one entry to the next at an 
acceptable speed. A typical Unifile entry 
would be structured as follows: 



more organised social life, 

David Lawrei 

versatil 

it yoi 

order 




a) an SLI recording the iength of ihe whole entry 

b} an SLI recording the length of item 1 

q\ item 1 

dl an SLI recording the length of item 2 

el item 2 

t) an SLI for the next entry etc. 

The Unifile program provides five facilities 
necessary to operating a useful storage and 
retrieval system: file structuring, information 
entry, amendment, search and display. First of 
all, file structuring. In the specimen entry 
given above, seven items of information were 



■66 YOUR COMPUTER. APfllL 19B3 




recorded about John Smith. The Unifile 
sysiem allows any number of named items to 
be specified and any information retrieved 
later will be reproduced under the specified 
headings. The only limitation here is that the 
whole entry must not exceed 255 characters. 

Ai to entry of informal ion,, once the types of 
informal ion to be recorded in each entry have 
been specified, the program requests entries 
on the basis of the structure the user has laid 
down. Entries will be stored in alphabetical 
of dcr of the first item. 



Using the amendment function, individual 
items can be changed or whole entries deleted. 

Two types of search function are provided. 
For the purposes of a normal search the user 
specifics, an item to be searched for and the 
program compares this with each item 
contained in its files. However, only whole 
items are compared — a normal search would 
only come up with John Smith if the address 
being searched for were "12 North Street", it 
would pass over the entry if the specified 
address were simply North Street - 

Special search, on the other hand, will 
identify every occurrence of a specified 
combination of characters such as North 
Street, or even 'Nor\ Special search is 
particularly useful for files which do not 
follow an orderly structure, such as recipes, 
where it may not be possible to predict 
precisely how many items of information will 
be needed and two or more end up being 
lumped together under the same heading, The 
disadvantage of special search is that il is 
considerably slower than norma] search. For 
either form of search, when the specified item 
is discovered, the whole of the entry 
containing it is displayed. 

The display function displays entries one at 
a time on command. All the program's 
functions arc called simply from a menu 
section which is displayed on entry to the 
program and at relevant points during its use. 

The beauty of the Unifile idea is that, once 
entered on to your ZX-81 and recorded on to a 
cassette, its uses arc endless. A single user can, 
at one and ihe same lime, be u&ing one version 
to store his personal address book, with only 
two or three items per entry, while another 
version stores vastly more complex club 
records or business data. 

The one major drawback of the program as 
listed is that it still does not use the memory 
space available as efJicieruty as possible — in 
fact it uses only half the space the ZX-81 
would allow. The reason for this is that we 
have referred to our data storage string on 
both sides of a string equation, as in line 730, 
Upon encountering this instruction the ZX-81 
promptly sets up a copy of BS in order that it 
may maintain a distinction between the new 



BS that it is being asked to create and the old 
BS it is being asked to use as material. This 
problem can only be avoided by fixing the 
length of BS in the memory of ihe ZX-fil and 
working within that fixed length. 

The method of doing this, outlined in the 
supplementary program notes, requires more 
program lines and is slight}}' slower in 
execution. This is because, instead of the 
economy of line 730, we have now to move BS 
in blocks whenever we wish to insert or 
remove data from the file. This version of the 
program should only be used, therefore, if you 
are likely to exceed 4K, characters in your 
intended file. In order to use the second 
version, BS must be dimensioned when the file 
is about to be set up. The maximum length is 
between 9000 and 9500 characters and to set 
up a new file simply enter DIM BS<9000) in 
direct mode, followed by Goto I. Other than 
that there is no difference in operation. 

395 Size is the variable used to store the 
number of characters so far recorded in 
BS. 

632 These extra lines chsck to see whether 
&$., which is now of fixed length, will be 
overfilled by the current entry, 

730 These two Gosubs replace the sections 
which added data or subtracted it from 
Q$. 

1170 We cannot now use the length of B$ as 
an indicator that the end of the data has 
been passed in a smirch, since no matter 
how little data is recorded, (be length of 
SS is sialic . 

1256 This line and 1320 us« the spurious entry, 
inserted into the f lie when it was first set 
up, in order to detect the end of the file. 

1880 This section - down to 1930 - uses an 
intermediate string - SS - to move 
blocks of 8$ up the string, in order to 
make room for more data. Since BS does 
not appear on both sides of a string 
equation any longer, it is not duplicated in 
the memory. Slightly more mamory can 
be made available for storage by reducing 
(he value ol SHIFT in lima 1360 and I960, 
though this slows the program down. 

1M0 This section telescopes the file when an 
entry is removed and is simply the 
opposite of the previous section. 



± <S(JTO & 

a sniic "L 
3 stop 

4B PBIMT * 
SB PRINT , 

" " ew p*itnr„" j,' 

CTuHK. OF FILE. 

70 PRINT , . • 

■'OT tan . ■■ 

B0 PRINT , , ' 

.fiV/CHftHGE „ r ' 
*& PRINT 
100 PRINT 



nr it-S" 



< FUNCTIONS HUfllLAP'. 
i I SET UP STfii,' 

3 1 (ENTER rtiFOP 

31 SEflpeM/PIS^ 

* I STOP. " 
PL ERSE ENTER UMI 



SH YOU RE0UIRE." 
113 5LOU 
ISO INPUT Z 

i3o et,s 

14S IF Z-l THEN SOSUS 250 

ISO IF E=i TrtCN COSUB *2<> 

1M IF 2-3 THEN COSJUO 103B 

170 IF 7. A THKN [IflMir* 3C>» 

iae cls 

ISO GOTO *t! 

[NT frt ie,5 



•PLCH&C M-PtCC 



INPORHH1 IOM HH5 BEL 



INT 
&C- IF NEtJ" 

220 PRINT 
■: ENTCREDt - 

aw stop ■ 

i£ -l <2> RE H |iiittii((itfti »#!.#*»* 

asn K»rn entkv structure 

a&o f>£ h **»■•***■ mnmntn 

870 prist ht a, a, "SEHanUtinMRt: 

"4 

3BQ PRINT .,"MOLl MRWV ITEMS IN 

EHCH ENTHY '- 

a 3D ii-jhuT X 

3«B ill 

aia dim fli(x,aei 

aae print rt u.e, 
9" 

333 FOR l^A TO X 

3*s print "rreM ■■> I, 

3S6S GPSUB 1374 

-SCO PRINT Q*ia TO t 



370 1.ET ft* ill •«( 

3S9 NEiCT I 

3B0 LET Bt = - *" iCMB| (aSSl 

400 ftf-TURN 

410 REM rtiltli)iiM»tllt«ttti 

i.'L" l--l.r" rjr.L-,M^i: T I- j I . ' 

*3B RCTM KlHltMU'tMlMMtt 

4,4a let «*»■■■■ 

450 PRINT nr n. j P. i-Otat3>fr#r- 

4ftB PRINT , , '-CDHMftHOS RUnii,RBLE 

i *■ 

478 PRINT ,/itHTCH rTCM SPECIF 
IED" , . , " J ■'"*■" TO QUXT FONCTI 
ON" 

490 PRINT "HftMlllMlMtttltt 
************ " 

400 FDR HI TO X 

510 COSUf- 1370 

52(1 PRINT Q* IS TO ) 

5 30 IF Bl<"i 2:t THEN RETURN 

340 LETT ft*»R»*C* 

530 ME NT I 

560. GL& 

570 LET Rt-CHRt (LEN C**1J*R* 

5B0 GOsuft eie 

sw torn ji;. 1 © 

PO0 REM iftllMIIHHIMtMHt 

610 REM PLBCe DRTR I« FILE 

eae pen *•• n •«*» *»*•»» r ■•»»♦ • 

630 FRST 
640 LPT CwS 

IJSlf L(T Clu-.l 

660 t>IM Cf ueai 

678 LKT M-CI 

eSi LET &II1 TO CODE R*C2>-l)sR 
4f3 TO l*COOC RIISM 

SOB LET ClU TO COOB e?tClJ-l?a 
OlICl.l TO Cl*COI>E BtlCli-H 

700 IF Of <C* THEM GOTO 736 

71B LET C=CvCOE>C B.»(C> 

72B GOTO 65* 

730 LET et^BIM TO C-H*R*tBilC 

TO 1 

74* SLOU 

750 RETURN 

760 REN lf»M«IHHttMMMtl4 



YOUR COMPUTER, APRIL 1983 67 



ANIROG SOFTWARE 



KRAZY KONG 16KVIC20 

All the thrills of the arcade game have been brought to life 
on this expanded screen, extra large characters and multi- 
screen presentation. Rolling barrels, hammer etc. are 
featured in the action inside King Dong's lair as you try to 
rescue the boy he h as abducted, K . B J J . S , £6 . 

ZOK'S KINGDOM 16K VIC 20 

An afternoon stroll turns into a nightmare. A footslip and 
you fall down the biztual hole leading to the middle earth 
kingdom of ZOK. A harsh and cunning ruler by any 
standards. You arc challenged to a battle of wits and 
endurance as the battle for survival starts in earnest. 

K,B. C6 

ORACULA 3KVIC20 

Count Dracula is asleep somewhere in his castle. He rises at 
mid-night and you must find him and drive a stake through 
his heart before he rises. A multi-screen graphic adventure. 

KB. £6. 

HOPPER 16/ 48K SPECTRUM 

SPECTRUM version of FROGGER with same features and 
bf ill ia nt g raphics* K . B , f 6 , 

PHARAOH'S TOMB 16KVIC20 

A graphical adventure game set in a pyramid. Once you 
enter, the only way out is with the aid of a key which 
unlocks the mystery of the Pharao's tomb. Beware of the 
mantraps the ancient Egyptians so painstakingly built. One 
false move and you will meet the same fate as befetl Other 
tomb robbers over thousands of years. 



FROGGER UNEXP VIC 20 

Popular arcade game. All machine code with brilliant colour 
graphics and sound effect. Features include snakes, 
crocodiles, lady frogs, turtles, cars, lorries and logs 

K.B./J.S.£6 

CAVERN FIGHTER UNEXP. VIC 20 

All M/C version of SCRAMBLE. Lasers, bombs, 
continuous scoring and sound effects give all the thrills of 
arcade game. Pilot your space ship through the tortuous 
tunnels and caverns destroying enemy missile launchers, 
fuel dumps and airborne fire saucers Four ships to 
complete mission- 10 skill levels. K, EL /J ,S. £6 

CRAWLER UNEXP. VIC20 

Armed with a laser gun, you must destroy the centipede. 
Destroy his mushroom cover and his allies mushroom 
laying flea and the homing spider, Fast and furious game. 

J.S.£6. 

SEVEN PROGRAMS (VOL 1) UNEXP. VIC 20 

This exciting collection of seven games, ail in Hi- Res 
graphics include popular board game Othello plus Bomber, 
Slalom, Bounce Out, Snake, Memory and Lunar Docker- 

K.B.£p. 

SEVEN PROGRAMS (VOL 2) UNEXP. VIC20 

This pack with all games in Hi Rt:s graphics contains 
graphical adventure game Goblin's Gold plus Ghosts, 
Breakout, Dare Devil. Minetiled, Grand Prix and Cobra, 

K.B.C6. 

TINYTOTSSEVEN UNEXP. V»C20 

Seven games for young children. All games are in Hi-Res 
graphics with bright graphics, The games include Super 
Snap, Simon, Bombs Away, Noughts and crosses, Duck 
Shoot, Mad Drivers and Santa, KB, £6 




GENEROUS DEALERS DISCOUNT AVAILABLE 

AREA AGENCIES AVAILABLE. 

SOFTWARE WRITERS 

We are looking for top class writers to join our growing software 
team. If you have written a quality game for VIC 20, SPECTRUM, 
DRAGON 32, ORIC 1 or COMMODORE 64, then contact us. We pay 
top royalties for accepted programmes. 



ANIROG AT COOP CRAWLEY 



Huge selection of software and Computer Books for 

SPECTRUM - ZX81 - VIC 20 - DRAGON 32 - 

COMMODORE 64 

Most of the software and add-on's advertised in this magazine for 

these computers available across the counter. 

Manufacturer's appointed dealers for DRAGON 32 — VIC 20 

COMMODORE 64 and ORIC home computers. We stock full 

range of peripherals (disc drives, printers and memory expansions) 

and support software. Come and see us for expert advice and 

comprehensive service, 



AR 



MAILORDER 
ANIROG COMPUTERS 
26 BALCOMBE GARDENS 
HORLEY SURREY 



Acch.* 






Payment EJy Cheque. 

P.O. /Access or Visa 

CREDIT CARD SALES 

HORLEV (029 34) 6083.2007 



6B YOUR COMPUTER. APRIL 1983 



780 
790 

8O0 
810 
820 
©30 
64© 
850 

see 

670 
880 



GOSUB 
PRINT 
PRINT 
PRINT 



(continued from pegv 67} 

770 REM CHANGE ENTRY 

REM ********************** 

LET CS=C2-1 

LET C1=C+1 

LET R$=" M 

PRINT "ENTRY ";C2i":-" 

FOR 1=1 TO X 

GOSUB 1&00 

1620 

rt 17, ie; " fcaatifflM " 

"COMMANDS RUPILBBLE:" 
" >NEULINE LEAUES ITEM 
' ( ">""222'"- DELETES UH 
">ENTER NEU ITEM" 
S90 GOSUB 1570 
900 IF G$ = ,,B - THEN LET R*=R*+B$ 
CC1 TO Cl+CODE BfCCl)-l) 
910 LET Cl=Cl+CODE B*(C1X 
CLS 

IF 0$ = "" " THEN GOTO 960 
IF 0* = "i2Z2" THEN GOTO 97© 
LET R*~R$+0* 
NEXT I 

LET BS=BS<1 TO C-l)+B$CC+CO 
DE B*<C> TO 1 
980 IF Q$«*" B ZZZ" THEN RETURN 

LET R$=CHRf (LEN R$+l)+R* 

GOSUB 610 

RETURN 

REM ********************** 

REM SEARCH 

REM ***********#*##*****#* 

LET 0=2 

LET C4«0 

let ca=i 

PRINT RT 14. i 

PRINT , , "COMMANDS PUAIL.ABLE 



UNCHANGED 
OLE ENTRY*" 



920 
930 
940 

350 

96G 
970 



990 
1000 
1010 
1020 
1030 
1040 
1050 
1060 
107© 
1080 
1090 



1100 PRINT "> INPUT ITEM FOR NORM 

AL SEARCH" . " >PRECEDE UITH ""SSS" 

" FOR" j "SPECIAL SEARCH" , , " >FRECE 

DE UITH '■■■IIX'"' TO 5EARCH"/TOR 

1ST CHARACTER OF ENTRY" 

1110 PRINT ">NEULINE FOR 1ST ITE 

M ON FILE" 

lie© print ■■ ****** **********.»*** 

************" 

1130 PRINT , /•INPLTT SEARCH ITEM: 
ii ■ 

1140 GOSUB 1570 

1150 LET S*^Q* 

1160 IF S*="» " THEN GOTO 1310 

1170 IF C+a^LEN B* THEN RETURN 

11S0 FAST 

1190 LET ClftC+1 

1200 IF LEN 5$<4 THEN GOTO 1240 

1210 IF S*f2 TO 4-) ="SSS" THEN GC 

SUB 1730 

1220 IF S* f 2 TO 4)« M III" THEN GO 

SUB 1730 

1230 IF C4=l THEN GOTO 1310 

1240 FOR 1=1 TO X 

1250 IF B$CC1 TO Cl+CODE B* tCU - 

11 *S* THEN GOTO 1310 

126© LET CIsCl+CODE B*<C1) 

1270 NEXT I 

1200 LET C^C+CODE B*(C> 

1290 LET C2-C2+1 

1300 GOTO 1170 

1310 LET C1=C+1 

1320 IF C+2«LEN B* THEN RETURN 

1330 CLS 

134© SLOU 

1350 PRINT 'ENTRY ";C2;";-" 

1360 GOSUB 1640 

1370 LET CSsCS+1 

1360 PRINT RT 16,12;' 

1390 PRINT "COMMANDS RUAILABLE: " 

i40©5|PRINT " >NEULINE TO DISPLAY 

NEXT ITEM", " ►""ZZZ"" TO QUIT FUN 

CTION" , " >""PAA "" TO AMEND", , ">"*' 

CCC" TO CONTINUE" 

1410 INPUT P* 

5 420 CLS 

1430 IF P$="CCC" THEN GOTO 117© 

1440 IF P$="" THEN GOTO 131& __-, 

1450 IF P*0"flftR" THEN GOTO 1510 

1460 LET C-C-C3 

1470 LET C4=€ 

1460 CLS 

1490 GOSUB 770 



1495 LET C2=l 

1500 LET C=2 

1510 IF P$s"ZZZ" THEN RETURN 

1520 CL5 

1530 GOTO 1170 

1540 REM ********************** 

1560 REH FUNCTIONAL SUBROUTINES 

1560 REM ********************** 

1S7B INPUT OS 

158© LET Q*=CHR$ (LEN Q$ + l) + G$ 

1590 RETURN 

1500 PRINT A* (1,2 TO CODE A* (1,1 

1510 RETURN 

1620 PRINT B*(C1+1 TO Cl+CODE 6 3 

(CI) -1) 

1630 RETURN 

1540 FOR 1=1 TO X 

1650 GOSUB 1600 

1660 GOSUB 1620 

167© LET Cl^Cl+CODE B*tCl» 

168© NEXT I 

1690 LET C3=CODE B*(CD 

170© LET C=C+CQDE B*(C) 

1710 RETURN 

172© REM ********************** 

173© REM SPECIAL SEARCH 

1740 REM ********************** 

1750 LET C4=0 

176© FOR JsC+2 TO C+CODE B$ tCi -L 

EN 5 $+5 

1770 IF S*(2 TO i)*"III" AND U>C 

+2 THEN GOTO 1820 

1780 IF B* (U TO J+LEN S*-SJ <>S*( 

5 TO ) THEN GOTO 1610 

1790 LET C4=l 

1800 RETURN 

1610 NEXT J 

1820 RETURN 



Two subroutines to be added. 

1830BREM ********************** 

1B40 REM MOUING DRTR 

1850 REM ********************** 

1860 LET SHIFT=512 

1670 FOR I=LEN B$-LEN R* TO C ST 

EP -SHIFT 

1660 IF I-SHIFT<C THEN LET SHIFT 

= X-C 

1890 LET S$-B$ (I-SHIFT TO I) 

ISO© LET B$ ( I-SHIFT +LEN R* TO 1+ 

LEN R$> =S* 

1910 NEXT I 

192© LET B*<C TO C+LEN R*-1)=R* 

1930 RETURN 

1940 FAST 

1956 LET SHIFT=512 

196© LET 5l2EsSI2E-COOE B*<C) 

197© FOR I~C*CQDE B$(C> TO LEN £ 

$ STEP SHIFT 

19BB IF LEN BS-I + K5HIFT THEN LE 

T SHIFTMEN 6$-I + l 

1990 LET S*=:B4(I TO I+SHIFT-1) 

2000 LET 5$ (C TO C+SHIFT-1J *S* 

2010 LET C*C+SHIFT 

2020 NEXT I 

2030 RETURN 



Tho$e fines complete the change. 
390 LET B*(i TO 4)**' , , "+CMR* (, 

395 LET SIZE— 5 

435 PRINT "FILE SIZE ;"; SIZE; "^" 

.; LEN B* 

632 LET 5I2E=5IZE+LEN R* 

634 IF 5I2E<=LEN B* THEN GOTO 6 
40 

636 PRINT RT 14, 10; "FILE NOU FU 
LL" 

638 LET SIZE=SIZE-LEN R* 

639 RETURN 
730 GOSUB 1660 
970 GOSUB 1940 

1170 REH DELETE THIS LINE 

1255 IF B»(C1 TO Cl+CODE B$(CD- 

1) a" ■ COPY ■■ THEN RETURN 

1320 IF B*(C1 TO Cl+CODE BJ(CD- 

1> ='• ■ COPY " THEN RETURN 



VOUfl COMPUTER, APHIL 19B3 69 



- 



Every computer needs a 

\CHATTERBOXi] 

"OK Spock, you win this time 
for 

ZX81 
SPECTRUM 



SAVEC££s 
>NLY 



SfNTKSS 



A'.. HAM 
SltjAftT 
SYSTEMS 




NASCOW.VIC, PET. 
BBC. APPLE, TflSflO 
IBM. CRAV. ETC 

(Please stale) 

At last! Genuine phonetic synthesis at a sensible 
price. Gives your computer an unlimited vocabulary 
(nothing more to buy!). Self contained speaker/ 
amplifier, Sinclair connector etc. PLUS Expansion 
socket tor BIG EARS AND Monitor socket for Music 
Board. Full instructions, technical notes and 
programme examples supplied with this outstanding 
educational unit oon 

OR COMPLETE D.LY KIT fc*jy 

DEALER ENQUIRIES WELCOME 

As seen on SBC TV ''Computer Programme" 

* BIG EARS * V/,, 

SPEECH 

INPUT 
FOR ANY 
COMPUTER 

Hugely successful Speech Htecognilion System 
complete with microoh&ne. software and lull instructions n jt q 

BUILT TESTED & GUARANTEED ONLY 3L*T <J 

PLEASE STATE COMPUTER: UK101 . SPECTRUM. ATOM, NASCOM3. 
Vrc 20, Micron. ZXJMHSV PET, TflS&O. MZBOK. APPLE II. BBC MICRO 

NEW: FAST MACHINE CODE FOR ZXBUSPECTRUM £7.40 




ZX81 /SPECTRUM 

MUSIC SYNTHESISER (STEREO) 
+ 16 LINE CONTROL PORT 



Play 3-part music, SOjnd filfects, 

drums etc. Full control ot attach, decay 

and frequency inpuUOulput nnes provide 

control and rromtor facility f<y Home Security, Robot Control. 

Model Railway etc etc. Works with or without 16K RAM 

Add keyboard to make a live performance polyphonic synthesiser 1 
Full msifucttons/soltware included 



AMAZING VALUE AT ONLY 
Extra 23 way connectors at £2,60 



£19.50 >„ 

£25.50 (BUILT) 



THE COMPOSER 

Music Programme for above synthesiser. 

Enter and play 3 part harmony. 

Includes demonstration tunes. Recommended £7,40 




COLOUR MODULATOR 

RGB in, PAL/UHF out (not for ZX) 



KIT £15 

BUILT £20 



SPECIAL OFFER 

SPEECH OUTPUT CHIP SX-01 

Phoneme Speech Processor 



I.C. £18 



DATA £0.60 



Please add VAT al 181* ID all prices. 

Barclay/ Ace ess orders accepted by telephone 



All enquiries 

S.A.E please 



WILLIAM 

t~* ~r~\ I /\ f— i ~t~ 44, BtHiford Gardens, 

& I LJ/ArH I Kensington. London W8 7EH, 

SYSTEIVIS LCd T ol 01-221 H31 ISofry - no enters] 



7vai m ™ 



£-/\UI 



LMJ 




from 



J.K. GREYE SOFTWARE LTD 



PLEASE NOTE 

As from March 31st the ZX81 
games currently available from 
this company will be marketed 
solely by two separate companies 
as follows: 



GAMESTAPE 1 
10 games for 1K 

GAMESTAPE 2 
Starfighter, Artist, Pyramid 

GAMESTAPE 3 
Catacombs 

From: 

J.K. Greye Enterprises 

16 Park Street, Bath 



GAMESTAPE 4 
3D Monster Maze 

GAMESTAPE 5 
3D Defender 

GAMESTAPE 6 
Full Screen Breakout for 1K 

From: 
New Generation Software 

16 Brendon Close 
Oldland Common, Bristol 



ANY ENQUIRIES CONCERNING THE 

ABOVE GAMES SHOULD BE MADE TO 

THE RESPECTIVE COMPANIES, 



70 YOUfi COMPUTER, APRIL 1983 



El 
El 
El 
01 
EJ 
El 
El 
El 
EJ 
El 
El 



VIC 20 



El 
El 

El 
El 
El 
El 

El 
El 
El 
El 



LASER ZONE BBBI J 

An utterly *», totally original masterpiece of videp games design. Lnir io CPnVtf 2 
ipa ceiriipi At onto. Feral the raw power a* yov hinge far lh* electro button end blast your 
enem** inio »ip»r*ln-ij clouds of space junL. f «l line humiSalion as i carelessly a\mt?tf W»II 
slim* Into rha side ol your l»t remainino sfupl Requires 8 v 1 UK and DEDICATION, Ee.00 * 
PAP 

ABDUCTOR J 

A classic n»w space game 1 ZAP (ltd twirling Alien nordes before lfiey Jim you — and 

induct youf hrgmanrjdS 1 Survive the assault 'Or long enough And you'll pet in (xlf* sl*geon 
your ipasesnip with eoubJa firepower 1 Awesome unexpired Vie ACIkST £6.00 t Sflp 

GR1DRUNNER J 

Firtahy, true treacle CuAluy On lha uneirpandod VrSl Shctp! (fpvrn lit* M0r»»fi1efl OPIOIDS 
nvajmg [ho -grid Beware of Ihrj pods and upperi! The t*eoma tp*ed. Sound ami 
0/apNcs gives you Its* Best Win available tor unetHfMbnrJfd Vie. C6.00 * 50p P*P. 

ANDES ATTACK <8K> J 

Your spacecraft mutt fttiaek the deseeno-ng ai*ns and l?uitr»te ]Haw evil Intern. Pry yaur 
Rjrnjet 1igh1er fjuer trie Ances mguniain range and protect your llama* (torn kidnap by 
nasi** Uf OS. f «Atur»s S Kinds of UFO. controls meludfl up. down, nwH , fve, thrust And 
smart bomb. Entifuslv in machine code. ReouiresflK e»pansipn and .s«-b: .■:■ tfl.M - 50p 
P4P. 

TRAXXMC{8K - EXPANSION} J 

This is VIC 20 cross breed Wtwe+n the new lamed PasAman' and (tie- gsrsc Qui* All in 
machine code, *as1 and 1un with joySOCl* controls, uses hVflos colour graphs* 8K Of larger 
expansion nMnJod Only £6.00 - 50p PaP complete with instructions. 



THE VERY FIRST COMMODORE 64 GAMES 



ATTACK OF THE M UTAMT CAM ELS J 

Plane! earih need* y*u" He* 1 *)* alien* nav* used seriat* engineetinc; to mutata tanwis 

front normally harmless beasts mto 90 foal high, neulreniurro shielded, laser -spirting 0ea.ln 
camels' 1 Con you By your t«iy. manoeuvr aisle tighter over V\e mountainous landscape lo 
wsaKen and destroy ITie camels colore 1M5y rnyade 1*ie human itfongHolo" You must 
witrisland withering lasnr tirg and alien LfFQs. Came Action sketches over 1Q screen 
lengths and tealures iupcrh scrolling, scanner. 12 p'ayet actions and unbelievable 
ar.rnauon 1 Play rtiis gam* and you'll nev*r be able la vusrt * *oo again without getting an 
ftchy trigger firtgei" Awesome mc action* £8.50 - 50p PiP. 

HOK64 

Roi ii a challenging g nme mvolvrng the cference o' your lunar CAM (rem a deadly rn«tPor 
$honer h.qx-6* iriclude^ ama^ino spn(e graph cS displays and tisaty sound afflicts, and an 
awesome rrothership o^piayilysu winmagam* fop 1 sce*«s are lasted aioog witn (He? 
rvarnes. TliS (XDgtern srtnwj ;uil whfll can » aehieved using only ConirnOdora-64 UasfC. 
Study the lilting ano learn hpw to use sprites a^d sound pn this DuUtAnding macf»ne. 
C4.M + MP Pif>. 



GRIG-RUNNER 64 j 

The No. I Pes! gsmr> lo* |h B V-c has Ueum improved l&r your OOVMOtJORE 64" GrOrunnef 
is a smash hit m the USA. Mow etpener-ca 1ni .'ightnina>lasl chailenoe or tf:* grid pn ti m 
Fea1ures31 s^.il levels »nd ej(eellenl Sdund ait! gj apf >cs Soretnooer fnoer ire? w,lfiew«rv 
gjaT-n' E8.S0 - Wfr PUP, 



SPECTRUM 



GRAPHICS CREATOfl <19K) 

Mol jult anoifwf cnA'Acler fldrtfj' f AlUwl you IP deliup no| eniy the 21 u*Cf ddlinAbie 

charaeurt, Aito Allows you to cUBtje (ha afftre re character ASCII *e1 CreAdrt, BYTES 

diet rtady tor you to load tftd your own programs tncl Jde* advanced Retted. lnv*n. Fund 

commands die. Compltl* wrin lull OOCumarttaoon Bid me BIN slrjlpmenl »nd u*g Oraphm 

Cflltof with rti SAsy pn-iceen cursor editing. £2.«£ t EOp PIP. 

BOMBER {16KI 

Yes. « lull tealure vemien o" if « popular game Buti'. auppirM tor tfie 1 6K or UK Sped ■ u.-n 

For Ortly C2.«S 4 »p P4JI. 

HEADBANGER (4SK) 

CokMiiuri new game sian-ir« Oieo the headbar^er who you muai guide to rich**, through 
an tncraaAirtg tSowar or heAvy n»!t, $un ponaset for neadfMnging but Be sure to take an 
Sipirn when the pain gets IPO mu-cn 1 Basic ' t. c to speed up action. Great graphics, mo* 
Animation Win ev«n dr.v* YV#i*m Stuan sysrem's vtnat synmes.ser to produce speedi 
Outout. Can you aflaTi the arade ol Rocker cias* One' or wid rtu t* Banv Van kw.'Cas^ 

5"? Sierr heatfbanging ro rJiiy and f<nd Put. f*S6- Itl-iVal 

SUP EROE FL EX (4»KJ wtatm 

Bounce Sid' ;he jpuce invader, around tne tcoen m|p the powor pods, keeping away ol 
course from the devil who chases you Around Ma sctaen. Steer with your Oetlei shields, Put 
tMiwa'a the nnes or you may be buned aJiva' Supe'd grajinics and tanlastlc sound on the 
4BK Spectrum only. Oply t*M on citeelt* *■ Sflp PAP. 



ATARI 400-800 



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VOOR COMPUTER APRIL 1963 71 




BBC 

Chris Melville 
plunges into the 
BBC's MOS - 
the handy 
machine-code 
routines 
already 
inside the 
Micro. 



Last MONTH 1 looked at the machine- level 
programming of the BBC using its assembler. 
This month I will deal with the useful 
machine-aide routines already inside the 
firmware of the machine — that is, the 
Machine Operating System or MOS, 

There are several slightly differing operating 
systems available, each one an improvement 
on the last. To identify your operating system, 
type: 

•FXO 
and then press Return. 

Operating systems around at the moment 
include the OS 0.1 — the first issue and t In- 
most common, sadly bug-ridden and lacking 
several important features such as the ability 
to drive discs* support extra paged ROMs, 
receive data on the RS-425 port and several 
important input-output routines. The OS 1 .0 
is a revision of 0.1, and can handle discs, 
paged ROMs, RS-423 reception, and has a full 
complement of system routines, although 
there are still some minor bugs. 

There were then various issues with minor 
differences until the OS 2,1 — (he one now 
being put on ROM. This features all the 
features of 1.0 as well as some useful new 
graphics routines to be used as starting points 
for sophisticated shape-filling algorithms. 
These will be incorporated into Issue 2 Bask 
as an extra set of Plot commands, 

When referring to the MOS* I will be 
referring to OS 0. 1 since this is compatible 
with the rest in most respects. I will point out 
any differences as I go. 

The operating system of the BBC computer 
is a set of routines which control the input - 
output and housekeeping functions of the 
micro. These include VDU drivers for 
printing, plotting — that is, everything that 
can be performed by the VDU function in 
Basic; sound-chip management — the routines 
that control the operation of the sound chip as 
specified in Basic Sound and Envelope 
statements; cassette filing system operations; 
and keyboard handling. The routines form a 
central core around which the high-level 
language interpreter operates, as shown in 
figure 1. 

Since the MOS routines arc powerful tools 
for the assembly language programmer as well 
as the machine's own interpreter, Acorn was 
careful that they were made as accessible as 



possible. There are several entry points to the 
MOS. Since the MOS is so big — around 16K 
— and contains so many routines, it was 
necessary to provide a modified method of 
calling these routines, rather than the straight- 
forward listing of a suitable calling address for 
each routine. 

The MOS is divided into 13 sections, each 
performing a particular task or collection of 
tasks, each of which has an address to which 
an assembly language, JSR or Basic Ca1l,USR 
can refer. 

Where there are several tasks to a section, it 
is necessary to specify which one is being 
called by placing an identification number in 
the accumulator just before executing the call. 
Figure 2 is a comprehensive summary of the 
OS features. 

The sections that comprise the MOS arc 
shown in the left-hand column of figure 2, We 
will take them one by one, 

Oswrch - OS WRite CHaracter in 
accumulator; also known as the "VDU 
driver", this section is responsible for the 
input output to the VDU — which includes 
the 32 ASCII control characters as well as the 
printable character set. 

The Basic statement VDU a,b,c v . . is 
equivalent to: 
A%-a : CALL OSWRCH ; A% = b : CALL 

OSWRCH 
or 
LDA- a : JSR OSWRCH : LOA# a ; JSR 

OSWRCH 
in Basic and assembler respectively. 

This is obviously a very powerful routine 
because it means that all Basic screen 
commands can be written as a series of VDU 
commands and therefore all can be easily 
performed at assembly-language level. 

Suppose, for example, we wished to do the 
following sequence of operations in assembly 
language: 

1. Select mode 2 — mode 2 in Basic is 
equivalent to VDU 22,2 

2. Set graphics foreground colour Fed — GCOL 
0,1 which is equivalent to VDU 18,0,1, 

3. Draw a line between (100,100) and (300,200). 
The latter is done bv 

MOVE 100,100 : DRAW 300.200 



INK 
OPER 




or VD U 25.4. 1 00: 1 00; 25, 5, 300; 200; 

which is again the same as 

VDU 25 A 100,0, 100,0.15.5.44. 1,200.0 
The operations can be written as one long 
VDU statement: 

VDU22,2, 18,0, 1,25.4.200,0.100,0,25,5,44. 1 ,200,0 
Which is easily written in assembly language: 
LDA# 22 : JSR OSWRCH : LOA < 18 : JSR 
OSWRCH : LDA#0. . etc 
Or, to make it more tidv and less bulky: 
FOR x% - 1 TO 17 
READ 3% 

[: LDA#a% : JSR OSWRCH :l 
NEXT x% 

D AT A 22, 2, 1 8, 0, 1 ,25 .4,200 ,0, 1 00, 0,25, 5, 44, 
1,200,0 

Outputting prompts or messages from a 
machine-code program can be a tedious 
business on a bit-mapped machine like the 
BBC, but again the Oswrch routine helps 
make light work of this. The following 
procedure can be used in an assembly- 
language program to generate the code to 
output a message, which is passed to the 
procedure as a string parameter; 
DEF PRQCMESSAGEUS} 

LOCAL i% 

FOR i% = 1 TO LEW (*s> 
t; LDA# ASC(M1D$u$,i%.1H : JSR 
OSWRCH ;| 

NEXT \% 
ENDPROC 

Of Course, before you can call Procmcssagc 
you must leave the assembler and then re-enter 
it after the call. The procedure generates five 
bytes of code for every character in the 
message, so ensure you have reserved enough 
memory, 

Oswrch, and all the other Osnames, is not a 
defined constant. You should set it at the 
beginning of a program and use it to aid 
readability. The actual value it has varies from 
one MOS issue to the next but you can set it so 
that it does not matter which MOS you have. 
This ts done by: 

OSWRCH » I &20E AMD ErFFFF 
The reason for this obscure-looking command 
will become clear later. 

Osbyte — OS routines that use the 
processor's registers to pass byte-size 
parameters. We have seen how the entire 



72 YOUR COMPUTER. APR«_ 1983 




THE 
MING 




range of VDU commands can, be performed by 
3 call to Os wrch but these do not constitute the 
entire range of screen-handling facilities 
provided by Basic, such as altering the flash- 
rates, of colours and seeing what character lies 
at the position of ihc text cursor. These are all 
performed in Basic by the *FX command, 
which also controls many other machine 
functions not connected with the screen — sec 
page 418 of the manual. The Osbyte routines 
provide the entire range of *FX commands in 
the same way as Oswrch did the VDUs, 
though this time there are many differing 
routines and we choose which one we want by 
placing an identification number in the 
accumulator prior to the call. In common with 
the VDU statement, the *FX statement may 
have more than one parameter, for example; 

■FX 12,50 
sets the keyboard auto-repeat to halt" a second. 
However, there are never more than three 
parameters so the entire statement can be 
performed in one go by passing the parameters 
in the A,X and Y registers of the 6502A, This 
avoids the need for repeated calling, necessary 
in the Oswrch section. For the call 

*FXa,b,c 
a is rhc call number and is passed in the 
accumulator; b is the first parameter, present 



on the most calls, and is passed in the 
processor's X register^ c is the second 
parameter, only present on a few calls, and is 
passed in the Y register. So the 

*FX 12,50 
call would be done as follows: 

LDA* 12 : LDX# SO : JSR OSBYTE 
Osbyte having been previously defined. In 
some cases success/failure indicators or results 
are returned in the register. You shuuld 
consult the manual to see further. The value of 
Osbyte is set by 

Osbyte = t &20A AND ftFFFF 
Osword — OS routines whose parameters are 
taken from specified words or memory. So far 
we can perform a large range of useful 
functions using Oswrch, where each call 
provides one parameter in the accumulator, 
and Osbyte, where each call gives up to three 
parameters in the processor's only three 
registers. There are a few more important 
features we would need regularly that need a 
lot more specified parameters than either 
Oswrch or Osbyte. For example it is vital that 
the OS provides sound-generating routines 
otherwise we would be left to manipulate the 
sound chip's registers ourselves if wc required 
sound to be produced from a machine-code 
program. However the Basic's Sound and 
Envelope statements need a lot of parameters 
— far too many to be passed in the A,X,Y 
registers of the processor. The technique used 
to make these Oswoid calla u to use the A 
register as before — that is, to identify the 
function required — see figure 2 — and to pass 
the Address of a block of locations in RAM 
where we have previously stored the 
parameters in a predefined order in the X 
register — low by« — and Y register — high 
bylc. A good example of this process is sound 
generation. 

Oswrch, Osbyte and Osword are by far the 
most useful MOS sections to the assembly 
language programmer but for completeness I 
will briefly describe the Other MOS parts. 

Osrdch — this MOS section deais with 
inputting characters from the keyboard. This 
is not really as useful as it sounds since most 
purposes will require thai typing ahead lug no 
effect and so an Osbyte call of 129 would be a 
belter method. Contrast this to the two forms 
of tnkey statements — a negative argument 
tests whether a kev is held at thai instant. 
OSRDCH = I&210 AND &FFFF 



Figure f. The user reietes to the operating system via the Basic interpreter. The hightevet 
language relates to thn operating system via machine code, but using prewritten OS routines. 




is the prefered definition of the address. 

Osfind, Osgbpb, Osbput, Osbget, 
Dsargs, Ostilc — These are all calls to deal 
with the setting up of a data file on the current 
filing system, and then performing transfers to 
and from it, 

Osnewl — this simply causes a new line to 
be started on the screen 

OSNEWL = &FFE7 

Osa*ci — equivalent to Oswrch except that 
a line feed is issued if, on calling, the 
accumulator contains StOD. 

OSASCI &FFE3 

Oscli — This provides another way of 
calling MOS routines. If, on calling Oscli, the 
6502A's X and Y registers point to the start of 
a command line in memo i v. Suppose wc had 

TV 0255 
stored in succcsive bytes from location cV2345 
then we would put &45 into X and &21 into 
Y. Then the command line interpreter will 
interpret and execute the command. 
OSCLJ = ! &208 AND &FFFF 
That concludes the machine-operating system 
sections, At this point it would be wise to 
point out that there is a price to be paid for all 
the power and flexibility of the routines 
provided by the MOS and it is speed. A little 
lime must be taken for the MOS to examine 
your call and cause execution of the correct 
routine inside of the section you have called to. 
However, this may not be such a disadvantage 
since the chances arc that, should you have 
written your own routine to do the job, it 
would not be as efficiently coded as those 
inside the MOS and would thus be slower 
anyway. 

Up until now wc have assumed that when 
we execute a call such as JSR Oswrch — with 
Oswrch defined as &FFFK — the program 
flow goes directly to &FFEE and the routine 
starts there. This raises an immediate 
problem; when a second processor is fitted the 
whole memory-map of the machine changes 
and it can no longer be guaranteed that the 
routine actually begins at &FFEE in the 
second processor. 

Similarly, if you were to update your OS to 
the laiest version, it would be highly unlikely 
that i hat particular routine was still held at i he 
same starting address. In both cases, any calls 
such as the above would fail and therefore the 
program would fail also, unless it was 
modified suitably. These problems are neatly 
avoided by introducing indirection into the 
call mechanism. In simple terms, the real 
sequence of events when wc call a MOS 
routine is: first, we make our calk as before, to 
arl address in the range &FFO0 to &FFFF. 
Second, the operating system then looks at two 
consecutive bytes in RAM and from them 
obtains a 16-bit address previously put there 
by the bootstrap on power-up or Break. This 
address may change from machine to machine 
depending on the MOSs and whether or not 
second processors are fitted, but it always 
points to the start in memory of the code that 
performs ihe routine wc originally wanted. 
This 16-bit RAM-held address is called the 
Vector for that particular call. Third, the 
routine can now he performed by jumping to 
the address given by the vector. 

Although all of the vectors arc originally set 

at power-up, since they are held in RAM there 

{continued on next page/ 



YOUR COMPUTER APFilL 1983 73 



(Continued front previous page! 
is nothing lo slop us changing them so (hat 
they point to our own routines in RAM. We 
could then write routines which completely 
replace those in the MOS, ■ 

t will now demonstrate writing a routine 
which performs a small operation before 
branching to the address ih.it was the original 
vector. This program will cause 'he BBC lo 
beep every lime a key is pressed on the 
keyboard, First of all we have to be able 10 
produce a Beep in machine code, which is 
achieved using a call to the Osword routine for 
sound generation. The stages for this are first, 
set up a parameter block — this can be done in 
Basic at the start: 
10 DIM PARAM% 7 : OSWORD = 1 I&20C) 

AND &FFFF 
20 FOR i% -. 1 TO 8 

30 REAOp% : ? (PARAM% +i%-lf ^P% 
40 NEXT 
50 DATA &1t J 0,&Fe,&FF,&t4 J 0,2,Q 

See pa[te -161 of the manual to see how a sound 
parameter block should be arranged- The Data 
statement gives rise to the parameters 
equivalent to those in the Sound statement: 

SOUND &11, 10,20.2 
Assemble the code to call up the sound routine 
in Osword: 

70 DIM P% 30 

80 I 

90 beep PHA:TXA:PHA:TYA:PHA 
100 LDA#7 

110 LDX* PARAM% MOD 256 
120 LDY# PARAM% OIV 256 
130 JSR OSWORD 
140 PLATAV:PLA:TAX;PLA 
ISO RTS 
160 I 

Run this program and then do Call Beep and 
you should hear a short tone. Lines 90 arid 140 
Save and Restotfe the A.X,Y registers, since 
this will be necessary in the full program. 

\\ "e must now decide how lo arrange things 
so that the subroutine tk-ep gets called every 
time a kev is pressed- When a key is pressed, 
three things happen, one, an interrupt tells the 
processor thai this, has occurred; two» the 
MOS uses its Osrdch routine io take this 
character from the keyboard; three, the 
character is possibly echoed ru the screen ar.d 
funnel action nuy be taken 

Since two and three involve Operating 
System calls, we could intercept them by 
changing the vector of which one we choose w 
that it points to Reep. It turns out that it is 
best to choose number two, Three further 
mod ili cat ions are required to complete the 
program. Save the value of the Qsrdch vector 
so that the proper Osrdch routine can still be 
called at the end of the beep routine. 
60 v% - I (&2101 AND &FFFF 
Now call the real Osrdch routine jiiet our 
Beep routine so that the proper things still 
happen when we press a character. 

145 JSR v% 
The Basic program should change ihe Osrdch 
vector to point to Beep, but only after its old 
value has been saved. 

170 '(&210) BE€P MOO 256 ?{&211] = BEEP 
D1V256 

The program can now be run and deleted; the 
key-beep will remain. Although not very 
practical in itself, this is .1 i:>->od illustration of 
the way in which it is possible to use a little 
ingenuity to attain a desired effect. 



MOS 










section 


Address 


Vector 


Function 


Routines inside 


OSGBPB 


&FFOK 


21A 


Load /Save Memory 




OSFIND 


&FFCE 


&21C 


Opening files 


Open for read (&40), Open for Write 
(&801 Close 101, Open for Read and 
Write l&cOl 


OSBGET 


&FFD7 


&216 


Reads Byte 


— 


OSBPUT 


8FF04 


&21B 


Writes Bytes 




OSARGS 


bFFOA 


&214 


Attributes - 




OSFILE 


&FFDD 


&212 


fi/W Files 


Contents of accumulator decide 
what to Read /Write 


OSRDCH 


&FFE0 


&210 


Reads from Input 
Stream IIS) 




OSWRCH 


&FFEE 


&20E 


Writes to IS 


Causes output of character or 
control code whose ASCII oode is in 
accumulator 


OS ASCI 


&FFE3 


none 


Writes to IS 


As above, but new line il 
accumulator - SKID 


OSNEWL 


&FFEE 


none 


Writes to IS 


Outputs line feed, carriage return 
only 


OSWORD 


&FFF1 


&20C 


Miscellaneous 


Reads line from input stream to 

RAM (CI 

Reads internal clock 1 1 1 

Writes internal clock (21 

Reads Interval tinier (3) 

Writes interval timer (41 

Reads a byte across thn Tube 151 










Writes byte to processors memory 
across Tube dJ) 
Performs sound (71 










Envelope definition (8) 

Reads <t pixel colour at specified 

position J9I 










Reads dot pattern on non control 










character (Al 

Returns palette/ logical colour 

relationship IB! 


OSBYTfc 


&FFF4 


&20A 


Effects 


The following are in numerical order 










of accumulator contents- 










Prints MOS report 










Choose input stream 
Choose output stream 
Enable v disable cursor edh keys (4| 
Parallel or serial printer select 
Define printer, ignore character 
Set serial port receive rate 17) 
Set serial pon transmit rate 
Select Hash speed of foreground 
colour (91 

Background 

Miscellaneous enables 

disables 

Empty buffers 

Select ADC channel number i16! 

Starts analogue to -digital conversion 

Clear s«fi keys 

Pause until fields are synchronised 

Explode user-definable key memorv 

Empty chosen buffer 

Cancel escape condition 1 124) 

Set escape condition 

Acknowledge presence of escape 

condition U26) 

Select base number for soft-key 

codes 










Perform escape 

enable, disable escape kev 

interrupt request for 










user 5522 










...... .ADA 68SQ 


OSCLI 


&FFF7 


&208 


Interpreting 
command line 




Figure 2; Summary of fecilitms offered by operating systems t.O and above. The cell numbers 


for the routines insidp arc sfunvr 


i in brackets. 





74 YQuRCOMFUtER . APRH, 1933 



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4 no ii»mp requlnwil 

Cambridge 

CB3 7BR 



UK price* ere *hown lirrt The bracketed (kie*» 
m eirpori piien which include <n&ui*d air mat I 
postage r.o all [he countries of Europe including 
Norway, Sweden, Fa-ilend and Dctfirruyrk For 
overseas cu*tom*rj ou»<d* Europe *n eutrj £5 
poimae per iwm bj charged. 
Ore 1 4&K computer £147 (£1581. 
xifil f 13.43 (£521. m primer £52.13 10611. a 
spectrum flflfl 70 If 129) it spectrum *BK 
£152 (f 172). 32K mancfy upfl'ade for 1SK 
spectrum (Issue 2 onPy> £44 tt*JI, i% 
microdnv* n/a In/al. ix rs232 n.'a Ln.''e), 5 

printer rolls £10.43 If IB), r»Bl ram pflH;ks 

1GK rze.oa (£38], MR £33 i£4i), S« CJ&lfSU- 

DRAGON 32 £173 



SINCLAIR AND 
ORIC COMPUTERS 




EG3014 32K £189. Disc driven stigie £199. 
dual £389. Doubte donsity convenor £72. 
High resolution o,rapbrci £82 Printer 
interface £39. 

UK101 AND 
SUPERBOARD 

32-48 diiptJV onpansion km UK 101 fS, 
S#ries 1 SuperboarrJ £14, 31K memory 
expansion board £60. Ctsjitwi £77.50- Word 
[MEKttkmf p*Ofl £ 10. Ceriii-onici interface kit 
£10. Cased doc drwes with DOS single £275, 
double Ml 5 Stand atom* floppy disc 
controller f85 

ORIC 1 48K 
COMPUTER £147.78 



PRINTERS , 
1 



COMMODORE 
COMPUTERS 

Commodore 64 £299 Vic 20 f 1». Kit To 
elkow the use of On orornery mono tHntll 
notordor with <ho Vie 20 and thS Commodore 
64 fS, Commodore utwilt record* lor 
Thftta computer* £36.80. Sup« aKpandflr 
high raspiiiiicn caniirjge £27.96. We stoc>t 
most iccesscihn. 

B BC 
MfCROCOMPUTERS 

A Mod« £28D. B Mood £347, 

GENIE 
COMPUTERS 

Mew colour Geruo £179, cwetl* recorder 

£25, 16K Rem »r(t£33. Light pen £15. 
Atco4»il«i tor Gun* 1 end Genio 2: — 



Low cost deiey wheels-- Snvm-Cotone T^l 
Ml*. Broth* Hftl £520. 0«v*iii Pr»xa3D 

Ayiewriter; |he Hwil m*acle. a combinod 
flsrsy whnt pnriier and Brectrk typewnter lor 
oruy £418. Epson MX80FT3 £324. Epson 
MX1CO.'3 £425. Ok! Microl.ne 80 C199. Oi. 
Mkrcrtine 82A £343. OI(i MtcrotinoSSA t-*ST, 
Oki Mlcroline 64 £684 Oki Muroa'rw 92 £437. 
0-. Microbne 9.3 £699 

5V POWER KITS 

Fu*y stabilized SV compoier and TT L rxrwx 
kit* 1 6A L7 S3, ISA £12,17. 6A £30 87- 

SHARP 
COMPUTERS 

We can supply £pson MXS0 end MX100 
crinwrt to rurt du^cl from lh* H2SWt b,'o 
|jo-» not n-r<-s!rdr (cf £4fi plui primer price. 
Wf nlM »pnt«lii-e in interfacing printers to 
Hie M260K, WZB0A and MZWB ttolh witi 
and without the Ir'o bo». 



SWANLEY ELECTRONICS 

Dept YC, 32 Gofdssf Rd., Swanfey, Kent BffS SEZ 
Tel Swanhsy (0322) 648ST 

Pottage £1 on Sinclair product* [OKI, £3.50 on other computer*. f4.5o on phn»« and 50p 
on other order* Plate* add VAT to all prices. Otfieijl credit end oversea* order* welcome 



VOUft COMPUTER, APRIL 1963 7S 



10 REM niitiltillllllll 
20 HEM ■* It 

30 RTM •■ r„U_ &/H7 tl 
40 HEN •fftttllttftttlll 

4V HEM VBI AND DC \ KUUIINfS 

50 FOR I-I5J6 TO )6|3iREAD RlPQK£ r t At«If tlPQKE 20*,4iPOKE 707 , * J A=U5R 1 153* 1 

AO DATA 104, 1*0, 10, J 62. A, 14"?,?, 7*,92,?M, 173, I », 2,205,200,2,240, l*. 1 9S1, 207, 208, 25. 149,3, 133,204 

70 DATS 173, 200, 2, 14L . I«,Z,I«, 13, 198. 20*, 200, 9, 149. 10. 153. 207. 1*3.208, Ml, 199,2, 1*7.4, 133,209, 

7*,98,22fl 

BO DATA 72, 138, 72, 1*6, 209. 189, 75,6, 141, 10,212, 141 ,2A, 20B, 232, 134, TOT, 104, 170, 104,64, 159, 192,24 

89 REM CHAM3E CHARACTER 6ET 

90 6DSUB 3000 

99 REM STRINGS HOLDING PRINT POS. 

100 0{n C*(?l,I»l7J,V*<7t,XS*l7l, ¥»(?>, I7*<7J ( V7tl7^J(6f 17) ,¥4*I7J . X14K7I , Y14M7f , I10*<7>, TIC* 
IT) 

105 D1H lIlll/l.rUH/l.IWl/Hfll/l.BlI/h^Tl/l 

110 FDA t"l TO 7i)r»*ltlH3««(D4-I):V5«tI1^3f»(B*IltX»(nH3tH(e+I)tVT*Ul<0««C9)tI**U>«0«»{S 

•J) 

IIS V6»{i)-O**(l0'l»:i:i4»n)-C*»tv> s y-|4*(l>-O«»<10-lS:)(l0t<I)^M«*(l0 I): YlO*< Il-CHMUO-ll 

130 JUl»CT}-Q**<10-t>lT|]*n!~a«*I<?}lI<f*(I>-Q«t1IO l>2T9»!II'-a«*(n*|l 

129 HTM I34XKF IWUT DEVICE 

130 BRUmilCr, l«!:rf»r 73t.,BTAflr/;aAiNEXT IiHKKTIUN 6,3i7 16; -ChciO«J- : POSITION 4.5l? 4*| '1 piddle 

131 KM 'paddil*' t » joystick ' IN INVERSE CHAR, 

133 POSITION B,*I? •6;-ur-:l 1 tKIT10N 4,7:7 t*l"2 jDV"lt 1 c k * I QPEH 11,4,0, "K* 
140 GET II, Ai IF A<49 Oft A>S0 TUN 144 
ISO POSITION V.'*;-' •*; 0***<ft> : IN&tV a *8 

199 REM PftQCnW INITIM IJATLON 

200 Din F(7},ST*a0),HP*<4l:»P«--h^p->FttllNAlT-6iPttxeU6-30 
210 AJF.SftW 720i FOR 1*1 TO IQiREAD fljSTtCT) ^HHKll :NFIT I 
73* DATA 7,3,6,0,1,3,2,0,0,4 

200 POS 200,37! 5-1 1 REH 208 IS BUG COLOR 

285 REM INITIAL DIFFICULTY SELECTION 

286 GRAPHICS It POKE 708,229iP0KE 712,1 53: 8QSUB 7Q0iOSSU8 400 
28? REN RESTART GAME 

290 FOR 1-1 TO 7iF<n=*JjNExT 1 : SCORE -O: NUrtiu6"0i BONUS -So 

300 GRAPHICS UPOKE Dt, START/ 256: GOSUB 7»t X»-)(5*: t*»Y3f jPOKE 708, 229 j POKE 709, 34i POKE 710,777; 

POKE 712,133 

305 RCH DftAH 

39* SOSUB 3CO0J POSITION 8,5iGDSUB 905 

sob rcji main i nnp 

309 IF 1MDEV-2 THEN GOSUfJ SOOiBUrO 330 

110 5* INT C (PADDLE 40) -43) /?0): |F g>7 TVCTt T.-7 

312 IF SO THEN 5*1 

314 S-0-S 

320 POSITION B,b: GOSUB 900*5 

3ffl IF IHWV 7 AMD 5TH[G<01-0 THTN GOT^JM tow 

330 [F IKDEV-l AND pTRlSfOl-O THEM 6USU* 1000 

339 I-OlIF HA1T>1 THEM MAtt MAIT l:GOT[] 150 

340 HA9T-HAXNA1T 

341 1-1 « I - TF 1-8 THEM 350 
3*2 IF F<II-0 THEN 341 
343 IF F(T>-2 THEN 347 

34* RESTORE OOO+liftEAD I)*, TJ Y , BX, A Vt POSITION BX,BYil IAiCHM ( 1291 : r H 1 1 -?-. flX r 1 1 AKi PY< I h BY: GOTO 3 
41 

347 RESTORE 8COM:READ DX,DY:P0SITI0N BX (I) .SVtlf: ? It:" *iBX r is 01 c J ■■ -l:i :Hv ,■ |> nv . I f TDY 

348 POSITION E)i£P,Br<H:? 46; CHR* ( 1 29! 1 IF BX<1>>3 AMD SXrlxu and 6Y(t)>5 AW »T|[K1I THEN 37 


249 KTTD 341 

330 IF BU6>1 THEN BU6-BU6- 1 1 GQ TO 360 

352 RJG'MAlBUCi: IF NUHtHJC? THEN 3*0 

35* lolHT(RH>(0)t7]<-liIF F(IJ» THEN 354 

356 r(I)-liNUHRJC»-«*JHIMO*i 

3*0 BUTO 309 

3*9 HFT1 BUG EQI TO FROG 

370 POSITION H,3i^ l*j -- ,'|FOR I-l TO 6 J POKE 708, 38i STJLHP 0, 100, 12, IfliFDH J-l TO SOiHEXT J 

37T, POKE 70a,S*HSOi*nj 0, ISO, 12, lOlFDR J-l TO K-jNTIT JiHE'T liSOUKD 0,0,0,0 

398 GOSUD 40fi:«!TO 2W 

399 run rnotiPT for hen w*t 

400 POSITION 4,13:? «*| 'PRESS start *i POSITION *,14r? ft*; 'TO PtAY'iREH USE IN INVERSE CHAR. IN TH 
E8E TW UNES 

401 POSITION 4,|*i7 *i>; -PAE5S wltct* I POSITION 3, 17:~> ■*: TOR [HFTIUHTY' 

402 PO¥E 53Z79,BtK>PLtK4$3Z7?ltlF If-ft THSN 430 

404 [F Kh5 THEN HAIHAl TtWXIH] T 1 i IWUDUG-HAXetfi-S: I F NfUBUiKS THEN HA I BUG- 30 1 HATHA IT-* 

«* POKE *5*,Q,P0KC 637,£.-? 7-mXHAIT 

*» FOR [-1 TO lOOtNEIT 1 

410 GOTO 407 

470 POSITION i, Lis-' ff*i~ 'iP05ITI0N 3,17i7 ■*■' 

430 IF fiCORE JHAJfSCDfiL THEN mi SO** SCORE 

44Q W ItlWI 

499 REW gOYirriC* SUBROUTINE 

500 S0-5TICKi0lilF SO 15 OR 30-13 THEN RTR1W 
510 ^•ASC4STt{S0-4l>|HErrURM 

599 RFH BUT !^IRRQUTtNE 

600 POKE 77,0:X-1:V-0:FOR K-l TO 4: X-I-l : Y-T-f liPOSI T10N i,Yl? «*lSP«<K,K> iHf'T K 
620 FOR K-230 TO 150 STEP -3: SOUND 0,K,S,]0:NFIT V. 

630 X-1:V-0:F0R hC- J TO 4: '"lt+l:Y-Y*l : POSITION J,Yr? ■*) - -iftEfT KtR£TURN 

69t REM CMANBE 01SPIAY t 1ST 

700 AHtW (540) f23*(PEEKf 561): POKE fl+J. l9t):POKE A* 13, 1 34 s POKE A>74,t34 

710 IT FEEK(A)0*6 THtN ft-A»l:IMTO 710 

7TO POKE A, 71, POKE A*3,7tPDtrt: AM,AStPWE A*3, PttKI *»71 tPOKE A**, P1EEK ( A*»l 

727 r»,T 3l2 1 54lPOKE 5iJ,*|P0KE 54286,197 

730 POKE 63*,0:PT1KF A57.3: - " 7-MAIMAI TrPOKF *.5i..0;P»I i57,l5i'' IHISCORE 

740 POSiriON 7, 19 t 7 t*j'<N* «or* hiyh":RETURN 

800 RCH X-Y HCHinbHTif * STARTING POS. 

001 DATA I, -1,0, IS 

SO? DATA 1,0,0,9 

D03 DATA l.l.O.O 

U04 DATA 0, 1,9,0 

803 DATA -1,1,18.0 

80* DATA 1,0,18.9 

DO? DATA -I, -I, IB, IB 

900 REM PRINT EYES OH FR06 

901 I*»X9*lY**Y9*|? •&;-! |-:RTTIJR« 




Gulp down those bugs as 
you drift lazily on your lily- 
pad with Stan Ockers' 
game for the Atari, 

Vol' n.rW ihc pari of an extremely hungry 
toad. Your objcci is io cat alt bugs before they 
reach you by poiiriing the load's bendy eyes at 
ihe incoming bug. You will find ihat your 
tongue snakes out and slurps up the buu> when 
you press the Fire button- Points are scored 
depending on the difficulty level. However, if 
ihfc bug hiis you, you die. The level of 
difficulty can be set at the si mi of the game. 
Either a Joystick or paddle conirollcr can be 
used. 

The bugs arc made to blink ort and off bv a 
Vertical Blank Interrupt — VB1 — routine that 
changes the bugs' colour to background colour 
and back. The VBI routine also has an 
important function in connection with another 
routine, the Display List Interrupt routine. 

Tlie display list is modified, lines 700-720, to 
change the text area to two mode 2 lints and 
also to set display list interrupts at three points 
down the vertical height of the screen. When 
these interrupts occur the DLI routine changes 
the background colour depending on a counter 
which counis the DLIs- During the vertical 

blank period this Counter is reset to zero, ready 
for the next screen. This technique gives 
separate colours to the sky, water and score 
areas. 

The character set has been altered enabling 
the toad to be printed in graphics mode I . This 



76 VOUR COMPUTER. APRH, l$aS 



ATARI 




gives a choice of upper case and punctuation on 
lower case and graphics symbols, h is best to 
pick the former and change the punctuation 
starting, with that above the numerals on the 
keyboard, leave the quotation mark alone. The 
set must first be moved from ROM to RAM 
and 1 use a machine-code routine stored in ZZS 
to do this - lint 3000. 

To move ihe tongue around, keep track of 
the print positions. I put these locations in 
strings; a set of Xs and Ys for each direction — 
lines 100- 120, The positions are recovered 
from the strings by using the ASC function — 
lines 1002 and 1004. 

Atari Basic can restore data values to the 
beginning of a certain line. This function is 
used in picking up the starting position a: id 
increments of the bugs — 346 ro start or line 
347 to continue — flags — F(I) — keep tract of 
the condition of the bugs; means the hug is 
active, 1 it is in motion and 2 means that it 
collided with something. 

Wait and Bug are counters thai skip over the 
start-a-bug and move-bug sections. When the 
counters reach zero, a new bug is started or all 
the bugs are moved and the counters are set to 
Max Wait, Max Bug respectively. The larger 
these maximums, the slower things go and the 
difficulty level is increased by reducing Mas 
Wait and Max Bug. ■ 



7-HAMA!T);BUHP^l 



902 ***Jll*(Yt»Y]l*t? f*|"( [") RETURN 

90S »*jn0tiY*~V10*.i7 tif"* •"[RETURN 

904 H»iJJM*jYt»YH*l7 •*! m t t'lRETUM 

905 IWdTfTHl'* HifX I'tRETlHH 
904 X*=X7*iYK=YM:? W>; *t **:RETURH 
907 XVKStlYt-ire*,? i*| "' -"iKETUW 

wn rem hmue routine 

1000 1-0 

1001 I-i+lilF I-B TWH 1010 

iw; position ftsciHimj.asrtYKTtjznri K.niCKT.ii-omihi 

100* POSITION KCIKtrm.ASCTYtm)!? «4b;CHKwM!>i SOUND 0,7-1, 8,BslF A-129 THEM GOTO 1050 

loos eon) toot 

1010 t-I-litF 1=0 T1€M 1020 

1017 POSITION ftSC(t»(rt},ASC<Y*(ttH? «AiC»Ct,I>iSOu* 0,7-1,6,6(6010 1010 

I020 IF «JRP=I THEN 60SUB 600: BURP^O 

1037 HXHD 0, 0,0,0 1 RETURN 

104V REM 60T A DUE 

10» FtS)-0 

1060 SajF£=SQJRE»10»<7H1finMITi,r<*E 6S6,<HPWE 437,81'' StOREt* ' 1 NUnBUB**UpU6- 1 

1070 IF STORE JFCWTS THEN fttlMAITHtAXHAIT-l :WlBOGHVHBU5-5i«]MJS-BOHllS<H00t (7-flAW 

1072 IF flflKBUKS THEN MAXEU6-5:f«](t4flIT=l 

1090 WE 654 ,Oi POKE 657,31? 7-NUHA1T 

1090 C« ([,!)■" 'fl-I+IieOTO 1010 

1999 REH TO1NT FROB SUBROUTINE 

2000 POSITION b,4:7 i4|*M M H :FOSiriOH 4,717 Mf+t »I*|HJS1TI0N 6,B)7 *t.\**— 1" 

2010 POSITION 6, 9:? •&; ■— t +— *:POSITIQM 5, 10a? Hi "t-+ »-«■ 

202O POSITION 3, Hi? 14j* "jRETLPN :REH INVERSE CHAR, IN THIS L IlC 

2997 RE* Dlflief DHflR. STT SUBR. 

5000 DIN Z7t 1321 (RESTORE JOlOtFOR I»l TO 32SREAO A|Z7*U t «CHR* tfl) : MEX f I 

3010 DATA 104,104, 1X3,204,104, 133,203,104,133,206,104,133,295,162,4, 160,0 

302O DATA 1 77 , 203, 1 43, 2W,1 36, 208,249,330, 204, 230,206,207, 20tf, 240,96 

5030 POKE 1 to, PEEK (lOA)-bi GRAPHICS 1 ST ART - i PEEK ( 10* ) + 1 } 1 254 1 PQffi 754, START /254i POKE 752, It? 'IN 

1 riM I7INfi - 

S040 A"U5R I AEH <£![•>, 373*4, START? I RESTORE JlOOtFQK I"START*B TO ST AftT* 1 J 9l REM AiPWZ t,AtNLXI t 

5030 REtlKN 

3-100 DATA 0,34. 83. 6;,34, 83, 34,0.0, 102,102, 102,0, 0.0.0,253,241, 241. 241, 129, 129,233,235 

5110 DATA 553, 199. 199, 199. 129, 129, 233, 235, 255, 143, Ml, 143, 1 29, 1 29. 255 . 253 . 255 , 129, 143, 143, 143, 12 

9,755,235 

3120 DATA 255. 129, 129, M3, 143, 143,253, 253, 255, 129,241, 241, 241, 129,255.255,755, 129, 129,241. 2*1, 24 

1,233,233 

3130 DATA 240,240,240,240,240, 240,740, 740, 15, IS, 15,13,13,1$, 15,13, 0,0,0,0,0,24,24,4s 

3140 DATA 233, 255,253, 233, 233, 233, 235, 233,255, 145, 143,235,145, 145,255,255 



YOUR COMPUTER. APRIL t£83 77 



A + F SOFTWARE A + F 



H K ^ 




II 




r 




Hi 


■ 




W mm. - - * v* h- n- -m. ■_ i 








a ji. 




■*•• 



PAINTER - BBC SPECTRUM, ATOM 

Completely machine coded Arcade 
game. 6 levels. 16 different screens- 
< Runs in colour on the Atom without 
F.P. BBC cassette £8. Disk £11,50. 
Atom cassette £6.90. 
Spectrum cassette £5,75. 



FROGGER - BBC h SPECTRUM 

More arcade action for the BBC (as 
photo) and Spectrum. Get your frog 
across the road, use the logs to navigate 
the river and get home. Beware the 
crocodile and snake, collecting the lady 
frog gains valuable bonus points. Beat 
the time limit or die. 
BBC Cass. £8.00 Disc £11.50. 
Spectrum cassette £5.75. 



Bisfc. ilia trass i 



*Hi 



BONUS 





flOOAB Tint HXDH 






■ ' i ■ a "■" 1 


PLANES - BBC 32K 

Spectacularly fast arcade style game. 
Options for different speed of game- 
^ even the slowest is fast! Many different 
screens and bonus scores, Graphics are 
really superb. 
Cassette £8.00 Disc £1 1 . 50 . 








^^^j ^^TT| 


ORIC SPECTRUM 

Two adventure games for the ORIC available NOW, Crazy Balloons — an excellent game for the 

Death Satellite and Zodiac. Both will run on the i$k machine at £5,75. 

16K machine. Cassettes at £6.90 per game. Speefile - Stock control/ data management 

__ . __., system for the 48K machine £10.00. 
UHAuUn 

Deadwood monopolies a western town — 1-4 Players, 

set your own time limit. Cassette £6.90, BBC 

Buccaneers — a piratical qame again for „, . , T , . .. 

,j rjl„ V-JLito re on Pharoah's Tomb - an interactive graphic 

1-4 players Lassette Lo.yu, , 

adventure game for the Model B. 

ATOM Cassette £8.00 Disc £11.50. 
Space Panic £6.90 Tower of Alos another graphic adventure game — 
Z oa =j ac £6.90 tn ' s w ^" run on t ' ie A or B machine. 

Cassette £6.90 Disc £11.50. 

Death Satellite £6.90 
Cy Ion Attack £6-90 

PLEASE NOTE THAT ALL OUR PRICES 
Atom U till kits still available from stock at £18,50. INCLUDE VAT B POSTAGE 



NAME 

ADDRESS 



5% DISCOUNT ON ALL SOFTWARE WITH THIS COUPON 

(Quote 830/ A for discount on telephone orders) 
PLEASE SEND ME: 



Please note prices include post & pecking 
You may also telephone 124 hrs) 



with credit card order 



830 HYDE ROAD MANCHESTER M18 7JD 
061-223 6206 (24 hrs) Telex 667461 (AHn A&F) 



$ WOIV NOOVUQ D88 WflUJOadS SfllHIS HIVlO 



73 VOUR COMPUTER, APRIL 1 983 



Listing J. 
S*KE¥ 10 "7*lB-tJBSM0LD:M- 

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13B READ KH'!C5l»K!J'NexT 



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1010. rot L&R «3 



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120 pk-tj: 
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!48.$Ch*r STX 1,7® 
130STY J.71 
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^ »»fc * but* (frsfing continued On next page) 



ALL BBC CHARACTERS 
GREAT AND SMALL 



Groups of people and the young arc 
supposed to find the 20-coIumn modes of the 
BBC Micro easier to read. Personally I have 
never found [his true. The double-width 
characters arc too far removed from any other 
form of primed character to be easily 
recognisable; double-width and double-height 
characters would be much more effective. The 
double-height characters of mode 7 can be 
used very effective ly to titie and highlight 
parts of the text without this disadvantage, 
however no other graphics mode allows 
different-sized characters to be mixed on the 
surten. Another shortcoming of (he text 
capability of the high-resolution modes is the 
inability to produce text in any other 
orientation than the conventional left -right 
direction. It is useful, for example, to label 
graphs by plotting text from the bottom to the 
top of the screen, or with games to plot a user- 
defined character in more than one 
orientation. 

Having grown used to having these facilities 
available on other machines, I produced the 
machinc<o<k program shown in listing I to 
make possible a much more flexible use of text 
in BBC high-resolution graphics modes. 
Specifically it will plot a string on to the screen 
in any One of four Orientations in any one of 
four character sizes. 

The four possible sizes are normal, double- 
width, double- height, and double-width and 
height, These sizes arc related to the normal 
character sizes for the graphics mode you are 



Mix double-height, normal 

and double-width text on 

the screen at the same 

time. Fintan Culwin shows 

you how to do it. 



Listing 2. 

232 DEF PR0CGOiflR<X5i*V5!,t^ino*> 
1085 LOCAL L^,T^ 

1019 IF J«!<0 DR X%>3 THEN PRQCERROR 
102B IF Y*<0 OR Y*>3 THEN PROCERRGR 
1030 FOR. L?.-l TO CENKitrlnO*} 

1049 T*<*nsccniD«<;*tri.rrtB,L5:*i>:> 

1030 IF T*;<32 0» T*>126 RHO Tf1<l23 

THEN PROCERROR 
iesa NEXT VJ% 

1870 COLL &0DEt-*trin^* 

1B9B ENDPROC 

1108 DEFPROCER.RQR 

Hie PR I NT "I incorrect u»* of 9ch*r 

furfCtiOn" 
U2B PRINT' "CAl'ltd utth "",-XTi", 

x<' ,"vy." .vs.' ,* "Sfttrirvs* 

1138 END 



Listing 3. 

133 .9cK*r LDR §0 

136 STfl I.7S 

137 ROL 176 ■«. STORE C% 
140 STK t70 

> 
1310 .R0 LDR &7S v norm*! or- inv*r»*T 



!32B BECi R12 
I33B LDY *7 



v-rtOTUfci 1 ! 
v *ttrt Of 



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invert 



lS3fl EQH! MFF 
]S*B 3TR 07., t 
1370 DEV 
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^ md Of invert 

•v« END OF ROT** 



currently using. The double-width and 
double-height options refer to the screen and 
not to the character — take a deep breath and 
think about it. 

The size is selected by the value of Y% when 
the routine is called. The values arc for 
normal, 1 for double-width, 2 for double- 
height and 3 for double- width/height. These 
are controlled in a similar manner by the value 
of X%. The routine Uscirdoes not perform 
any error-checking on the values, of X% and 
Y%, Values of Y% in excess of three will cause 
a default of double- width/height, but values of 
X% higher than three will cause disastrous 
results. 

The string to be plotted is passed to the 
routine via the Call command. The first 
argument to the Call command is the entry 
point to ihc routine. In this case, The absolute 
value is &0D21 labelled by ihc variable 
GChar. The second argument to the Call is the 
variable name of the string, and not the siring 
itself. The characters within the string can 
include any printable character. A random 
noise pattern will result if any control codes 
are passed in the string. 

It is possible to perform error checking on 
the siring and an the control variables from 
within the routine, bui in ihe interests of 
keeping the code as short as possible 1 have 
omitted them from the version presented here. 
Instead, I have included listing 2 which is a 
procedure to check for these errors and halt 
{continued on next page) 



YOUR COMPUTLR. APKIL 13B3 70 



(continued from previous page} 

program execution if such an error occurs. It 

uses X% and Y% as formal parameters to the 

procedure so it is safe to use thtse within the 

main body of the program without any 

confusion. 

The routine was written on a machine fitted 
with operating system 0-1 EPROM. One of 
the jobs the routine has to do is to calculate the 
position in memory where the character 
definitions have been stored. The new user 
guide describes an Osword call implemented 
from version 1.0 onwards which will do this. 
If you have OS 1.0 fitted, the code given in 
Sis ting 3 will ensure thai the whole program 
runs smoothly. 

Routine protection 

The routine occupies less than 200 bytes hex 
and can thus fit into less than two pages of 
memory. Page &0D is reserved for user- 
supplied resident routines. If this and the 
following page are used, then the routine will 
only occupy one page of what is usually user 
memory. The routine has to be protected 
against the Resetting of Page by the operating 
system when the break key is pressed. This is 
done by the Key 10 definition in line 5. Before 
a final version of the routine is loaded or run 
this page must be reserved for it by resetting 
Page to &1000. 

Once a working copy of the routine is 
successfully installed in the memory al this 
position a direct copy of the code can be made 
by Saving this section of memory. To do this 
use the "Save command 

For example 

'SAVE J 'Gcbar J ' 0O00 0FFF 



The code can be directly loaded back into 
memory using the "Load command 
•LOAD "gclw" 

Both of these operations are best done with 
full CFS information displayed. To do this use 

the command 

*OPT 1,2 

Remember to reset Page .before attempting 
any Basic and to protect the Reset as 
described. 

A note to model A owners or even 
extravagant users of model Bs. Up to two extra 
pages of memory can be obtained by resetting 
Page downwards. Program memory usually 
starts at &0EG0. The page below this is 
reserved for user-supplied routines. If these 
are not being supplied then Page can be reset 
to &OD0O to allow Basic to use it. Page &0C is 
where the user-defined character information 
is stored. If user-defined characters are not 
being uScd within the program then this also 
can be used for program memory. The reset 
has to be protected against the Break key as 
described. 

Most of the routine is explained in outline 
by the comment entries in the listing. It 
should be possible, if you are familiar with 
6502 machine code, to reduce or enlarge the 
number of options fairly easily- The only non- 
standard part of the code is the method of 
storing the cursor movement information. 
The information for moving the cursor is 
stored in the 16-byte data block labelled by 
M%. 

Each byte of data holds the information for 
horizontal and vertical movement of the 
cursor. The byte is split into two nybbles — 



four bits — each nybble holds a three-bit 
number and the sign. The first — left-most — 
nybble holds the up-down information in the 
order high bit, middle bit, Low bit and sign. 

Where sign is for upward movement and 1 
for downward movement. The second nybble 
holds information for left /right movemem in a 
similar way but the order of the bits is 
reversed. Sign indicates right ward move- 
ment and sign I leftward. This allows the 
maximum movement between characters of 
seven-character cells in any direction. The 
information is extracted from the data block 
decoded and implemented in the cursor 
subroutine. 

If you are not conversant with BBC 
assembler the program can be copied directly 
into your machine. 

Type and test 

To facilitate typing and testing the program 
the actual location of the code can initially be 
left to the machine operating system. This will 
allow the routine to be entered and tested 
without bothering to reset Page, and possibly 
overwrite the program if any problem?, arise. 
1*0 do this omit lines 5, 40, 60 and SO until the 
routine has been fully tested. Then Load the 
program from &1OO0 upwards before re- 
entering the missing lines which locate it in 
pages &0D and &0E. 

The final point to note is that the 
information is actually sent to the screen by 
continually redefining character 224 which is 
consequently unavailable for other uses within 
■he user program. This restriction is 
accounted for within the ProcGchar procedure 
listing given. 



(fisting continued from previous page} 






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2410RTS v« END OF DwlD ** 






4330SEC 










3OG0 V***** STRRT OF 


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3039RTS ^ ** END OF 


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5393 ^***** UTILITY ROUTINES ***** 

6000 .OtoO LDY #7 \ cePie* D5t to Gchi*>( 

6018 .zl LCR 05:^ V 

6020 STR crW*5i,Y 

6030 DEY 

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V0UR COMPUTER. APRIL 1983 81 






THE SPEED of Forth and being able to redefine 
standard graphic characters art fcuiurcs uf the 
Jupiter Ace which make it ideal for improved 
quality printing — cither on screen or on 
paper — a parallel printer has been promised 
by Jupiter Cantab, 

The Jupiter Ace Handbook explains that the 
character set is contained in RAM addresses 
11264 to 122S7. These characters can be 
changed by writing new values into this HAW. 
but cannot be read back again. The initial 
character set is created from the ROM when 
the computer is switched on- The t?w data to 
generate the characters is contained in ROM 
bytes 7547 to 8187 which consist of an 
abbreviated set of ASCII characters 32 to 127. 
If you want to see this data, define the words 
DD and Changed as follows: 
: DD 
DUP 16 + DUP ROT 
DO 
I C@ 256 + 2 BASE C! 
. DECIMAL 32 EMIT I . CR 
LOOP: 
: CHANGED1 
11264 48 8" + 80 
DO 
DUP 128 SWAP C! 8 + 
DUP 255 SWAP C! 7 - 
LOOP 
1- 255 SWAP C! ; 

Now enter 

CHANGE01 SNVIS CLS 7547 DD 
and enieT further DD as required. The 
program displays the ROM data in succession 
— with an additional character on the left-hand 
side — and the byte number at the right. The 
word Changed has turned the character 
into .i black square and ihc character 1 into a 
white square, so that the ASCII characters arc 
readily discernible. 

If you look carefully at this section of ROM, 
you will see that the ASCH characters 32 to 62 
copy seven bytes fit a time, The rop line of 
each character is a zero byte. ASCII characters 
63 to 94 only use six bytes each with zero top 
and bottom, while 95 to 126 use seven as 
before. Finally character 127 uses all eight 
bytes. 

When you have finished looking at the 
ROM, enter Abort to clear the data stack. 

The ROM data provides a very simple 
means of returning any character set you may 
have devised back into the original form. For 
example, we do not want Os and Is to look like 
black and white squares for the rest of their 
lives. The word Reset emulates the action of 
the computer when it is first switched on, 
restoring to original any altered characters 
between 32 and 127. 

Two utility words are needed — ROW 
which enters a single byte where ordered, and 
Block, which copies a prescribed block of data 
from the ROM. 

: ROW 
OVER Cf 1 + ; 

: BLOCK 
ODO 
OVER C@ ROW SWAP 
1 + SWAP 
LOOP ; 

: RESET 
7547 11S20 31 
DO ROW 7 BLOCK 



CHARAC 






YOUR 




LOOP 32 

DO ROW 6 BLOCK ROW 

LOOP 32 

DO ROW 7 8L0CK 

LOOP 8 BLOCK ABORT ; 
Now Redefine DD and Change OL This 
removes them from the dictionary and leaves 
jusi Row, Block and Reset. Define another 
word Test to display all the characters on the 
screen: 
:TEST 

BEFORE 




127 32 

DO I EMIT 

LOOP 4 1 

00 I EMIT 

LOOP ; 
You will notice thai three graphic characters 
appear at the end — we will need to look at 
these later on; they will be changed into 
something more useful. 

Examine the letters critically — several 
things detract from their appearance; the lines 
c*r writing are too close together; some lower 
case letters seem to be too short, not lining up 
with the top of the other letters; and the 
descenders — the tails that are supposed to fall 
below the line — hardly descend at all. 

To overcome crammed writing one simple 
remedy is to print a blank line between lines of 
type. At first this might appear io space the 
lines out too far, but if the blank lines are used 
to draw better descenders and we increase the 
size of the capitals, the spacing looks just 
right. 

The word Capital increases the height of 
ASCII characters 63 to 94 — it simply doubles 



82 YQUR COMPUTER. APRIL 19S3 



<■ 



FORMING 





Roger Liddiard's programs 

wilf help convert 

your deformed 

characters into 

true descenders 

of the 

Ace 



up on the top i wo lines of the characters; 

: CAPITAL 
7764 11768 32 
DO 2 BLOCK SWAP 

4 + SWAP 6 + 
LOOP DROP DROP ; 

The offending Lowercase letters are 
stretched in a similar manner to smooth out 
their tops; 

: LCASE 
1 14441 4 14 147977 120481*0 
DO 3 PICK BLOCK 3 PICK - 

SWAP ROT - 7 + SWAP 8 + 
LOOP DROP DROP ; 

Now to put proper tails on your letters. The 
letters g, j, p, q and y are re-defined and their 
tails are drawn in graphic characters 1, 2 and 
3. Yest you only need three tails — those of g> 
j, and y are the same. 

The word Descenders make* this trans- 
formation — of course the mils are lost until 
we double space the typing, bur you can sec 
them being formed in the last three characters 
of Test. 



; DESCENDERS 

4 6 64 64 m 68 11272 

DUP 24 

DO ROW 

LOOP DROP 3 

DO20 
DO SWAP ROW 
LOOP 6 + 

LOOP DROP 

8141 12237 8085 12173 8078 12185 

8035 12117 8015 12093 5 

00 3 BLOCK DROP DROP 

LOOP; 
If your Jupiter Ace has no additional 

AFTER 






































































































































memory, you will soon be running out of 
space, but do not worry — once the new set of 
characters has been furmed, we can clear ihe 
dictionary and start again with some new 
words. So Save what we have done so far, then 
enter 

CARTAL LCASE DESCENDERS FORGET 
RESET 

which should clear out the dictionary — check 
it with VLisi. Now the finale. 
St art by entering two utilities: 
32 VARIABLE NN 
: PRINT ; 

Then define the word DType. It is quite 
long but its effect is dramatic: 
: DTYPE 
32 NN I FIND DUP 6 + SWAP 5 @ 13 
BEGIN 
DUP32> 
IF 

ELSE DUP NN I 
THEN NN@0> 
WHILE 
BEGIN 

INKEY DUP 80 = 
IF PRINT 
THEN 
UNTIL NN @ - SWAP DUP NN @ + 
SWAP NN @ 

TYPE SWAP 32 NN @ - SPACES 32 
DO 113 113 113 112 112 121 106 103 
15388 @ 32 C@8 
DO DUP 4 ROLL - ROT + SWAP 
LOOP DROP DUP 
IF 

ELSE DROP 32 
THEN EMIT 
LOOP 

REPEAT DROP DROP : 
DTypc is used in conjunction with a word 
containing text. It starts on a new line so the 
text is best arranged in complete paragraphs. 
The first 32 Letters are typed out, followed by 
a line of blanks and descenders. Ie then waits 
Tot you to press, any key before repeating ihe 
process with the next 32 letters. This control 
facility is very useful when you need to control 
the amount of text you wish to display, for 
example when a printer is used to copy a 
screenful of text. A dummy word Print has 
been included — if the letter P is pressed this 
subroutine is called up — it will be useful in 
the future. To use DType, define some text 
such as 

: PI ." abcdcfghijfclmnop etc. " ; 
preferably with more than one line of 
characters. Because DType uses the word 
Find, and calculates the length of text in PI, 
another word must appear in the dictionary 
after Pi, Otherwise the bytes in Pi's header 
which define its length, will not be complete. 
So add a dummy word :P2 ; on the end. 
Now enter 

INVIS CLS DTYPE Pi 
when the first line is complete, press any key 
and the next line will appear. The advantages 
of storing text in colon definitions are that the 
length of text is not limited to 256 characters 
and full Edit facilities arc available. En 
addition, memory space is not wasted in 
defining new words such as String. Successive 
paragraphs can be displayed 'hv means of 
DTYPE P1 DTYPE P2 DTYPE P3 etc 
and paragraphs can be interspersed with 
additional blank lines by the use of CR as 
required. Your text can be Saved on tape in 
the normal manner. 



YOUH COMPUTER, APRIL 1983 83 



This program will run only on the IK 
ZX-81, and so RAM packs must be discon- 
nected before the program is loaded. Before 
crtiering the machine code, space must be 
reserved for it. The easiest way to do this is 
with Rem statements, so type in lines I and 2 
as: 

1 REM 344 zeros 

2 REM 167 £croa 

[[ is advisable to cnier lines I and 2 in Fasi 
mode. 

When the Rem statements are complete, 
enter the following hex code loading program. 
10 LET X - 16514 

LET AS 

IF AS - "" THEM INPUT A$ 

IF A 5 - "S" THEN STOP 

PRINT AT 0,0:X,A$ < TO 2 } 

POKE X, 16* CODE A$ + CODE AS {2} 

- 476 

LET X - X .4 I 

LET AS = AS < 3 TO | 

GOTO 30 

Run the program, and in response to the 
input prompt enter the bytes in the column on 
the left-hand side of the address column — each 
two characters make one byte. For example, 
Doe may enter the first five byte* of the 
machine code in a block or one byte at a time, 
thus: 

2A3240 IMEWLINE 54 NEWLINE 5D NEWLtNE 
and so on. l>o nol enter any spaces with the hex 
codes. Take your time when entering the 



20 
30 
40 
50 
60 

70 
80 
90 



machine code, 3$ Ortc wrong byte could cause 

disaster. If at any time you make a mistake, 
break out by inputting a single S. Then type in 
line 10 again, but this time with an address you 
know to have been correctly loaded. Then 
continue from that address by running the 
program. 

When all of the machine, code has been 
entered, break out by entering a single S, and 
then type in line three as: 

3 RAND USR 16630 
then delete lines 10 to 90. 

Now Save the program before running it. 
After saving the program, type in, us. direct 
commands 

RAND 
then 

RUN 

If everything is running happily, your \c\ 
should, be re$ting on a flat area of landscape 
ready for take oflj a hilly landscape should be 
moving towards you, ;»nd the flak should be 
moving across the screen. If your aeroplane 
collides with the hillside if will explode, 
stopping the program, 

Keys 1,2,3,4, 5,Q,W,E,R, and T move your 
plane up, and keys A,S,D,F,G,Z,X,C, and V 
move it down. Keys 6, 7,8,9,0, Y,U,I,0,P drop 
a bomb from the jet. Shooting a base 




represented by an A — earns you 10 points. 
If something has gone wrong, turn off the 
power supply and then reload the program 
from tape. To debug it, enter (he follow 
program: 

10 FQRF - 16514 TO 17030 

20 LET X = PEEK F 

30 PRINT CHR$ {INT (X/16I * 281 
CHR$ |X - WTW16J -16 + 28) 

40 NEXT F 
and run it. The machine code is displayed 22 
bytes at a time. After checking each byte for 
errors, euien 

CONT IMEWLINE 
for the next 22. When an incorrect byte is 
found] correct it by Poking its address with the 
decimal equivatem of the correct byte — see 
conversion tables at the back of the ZX-81 
manual. When debugging is complete, delete 
lines 10 to 40. To speed the game up, 
Poke address 16627 with a number 
between 1 and 15; ki slow rht 
game down. Poke 
address 

16627 with a number 
between 16 and 255. 





K?5J t 


2fi 


16515 


32 


1R516 


46 


lfiH17 


54 


issie 


SD 


16515 


29 


XGS&e 


29 


16521 


IS 


16522 


29 


16523 


a g 


issa* 


29 


16525 


19 


16526 


,2-2 


1652? 


3£ 


uasas 


46 


15529 


C9 


16530 


3E 


16531 


1C 


16532 


OS 


16533 


66 


1653* 


£>7 


16535 


10 


16536 


F& 


i©S37 


3E 


16536 


75 


16539 


67 


185410 


0a 


165*1 


09 


165-i< 


36 


1654a 


60 


16544 


66 


165*5 


13 


165*6 


D7 







15568 


36 






16581 


aa 






165BZ 


2.R 


1654 ,' 


IB 


16S63 


0C 


165*6 


n> 


16584 


■Jfl 


16543 


35 


1658S 


11 


1655Q 


76 


16566 


87 


16551 


D7 


1656 7 


00 


16552 


&D 


165e« 


13 


16HE!? 


20 


1&S?00 


11 


16554 


F3 


1&5<P^ 


40 


16555 


BE 


1G591 


40 


16556 


82 


105SE 


05 


1653V 


3L 


15593 


06 


16556 




1&5S* 


C& 


16SS5 


66 


16595 


01 


16SBB 


13 


lt=>L-^_ 


14 


16561 


67 


lbb- 


00 


1A!nft£: 


MS 


16SW 


Et 


16563 


FO 


16S4 = 


."-J 


16564 


35 


16&0V 


23 


16565 


"7& 


1660-1 


72 


16566 


I>7 


166«i^ 


23 


16567 




16603 


EO 


161566 


30 


1650* 


09 


1C569 


F3 


16605 


CI 


16S76 


an 


15685 


10 


16371 


0C 


16687 


f2 


16572 


40 


16608 


Sfl 


16573 


11 


1660 a 


&C 


16574 


rvt 


16610 


40 


18573 


Q» 


16611 


11 


16576 


19 


1G612 


RR 


16577 


36 


16613 


88 


16576 


66 


155 1* 


13 


16579 


23 


16615 


22 



16616 


3C 


16617 


.!(?> 


16618 


11 


16613 


12 


16620 


QB 


16621 


19 


16622 


2fi 


16623 


3E 


1&&S4 


40 


15625 


01 


16626 


00 


16627 


10 


16626 


05 


16639 


78 


16630 


F5 


1683>1 


00 


16632 


20 


16633 


Ffl 


1663* 


3R 


16635 


*C 


leesb 


48 


l&b37 


3C 


16633 


32 


16639 


4C 


16640 


&P> 


16641 


cs 


15642 


*7 


16643 


SB 


16644 


77 


16545 


3R 


165*6 


0C 


1684-7 


40 


1664 Q 


11 


16649 


68 


16650 


00 


16651 


13 


16852 


8E 


16663 


03 


1865* 


54 



16555 


sr% 


16556 


23 


1665"? 


06 


16658 


12 


16653 


76 


16568 


FE 


16661 


tfO 


15652 


26 


16663 


BC 


16664 


FE 


16565 


68 


i &&C*fe 


PS* 


16667 


04 


16656 


3E 


16560: 


36 


16670 


18 


16671 


11 


16672 


FE 


16673 


1& 


1667* 


28 


16575 


0* 


16676 


3C 


16677 


80 


16678 


18 


16679 


09 


16660 


FE 


16661 


00 


16632 


30 


1666:3 


05 


16654 


IK 


16685 


FE 


16686 


as 


16607 


88 


L6656 


F3 


16669 


12 


16690 


23 


15631 


13 


16632 


10 


16633 


DD 


15634 


23 


16635 


BO 


16636 


20 


16637 


D4 


16633 


11 



It, IS 

16700 

16701 

16702 

16703 

16704. 

1670S 

16705 

16707 

16 70S 

16789 

16718 

16711 

16712 

16713 

16714 

16715 

16716 

16717 

16718 

16713 

16720 

16721 

16722 

167E3 

15724 

16725 

16726 

16727 

ll>7E3 

167E3 

16730 

16731 

16V3S 

16733 

16734 

16735 

16736 

16737 

16733 

16733 

18740 

16741 

16742 




12 
00 
19 

E5 

CD 
82 

40 
44 

--£ 

01 

3C 

FE 

05 

20 

02 

35 

01 

10 

F7 I 

47 

El 

11 

ec 
rr 
38 
88 
13 
10 
FB 
FE 
0* 
28 
50 
FS 
E5 
CD 
82 
40 
7C 
FE 
32 
EX 
30 

as 









64 YOUR COMPUTER, APRIL 1 913 



GROUND 




Your terrain-hugging r 
destroy ground targe 

weaving a perilous p 
the heavy ffak in Phi 
machine-code gan 




i6743 

1874* 

167*5 

1G7*B 
167+7 
X67*e 
16749 
167S8 
16751 

16762 

J67S? 
1675* 
16755 



1676& 
1675l» 
16760 
16761 
167G2 
16763 
16764 
16766 
16766 
16767 
16766 
16769 
16770 
16771 
16772 
16773 
16774 
16775 
16776 
16777 
16776 
16779 
16766 
1G701 
16762 
16763 
167S4 
IB ,*. ib. 

167S6 
16767 

167SS 



36 
26 
Fl 
3C 
4-7 
3E 

04 

90 
4.7 
FE 
00 

£6 
66 
11 

EC 

ff 

id 

36 
6© 
10 
FB 
2fl 
3C 
4-0 
33 
7£ 
FE 
62 
26 
66 
SB 
IS 
4-R 
CD 
BB 
62 
CD 
4-5 
26 
04 

ce 

iD 

26 



16.763 



16791 

16792 
16793 
1579* 
16795 
16795 
167ST 
16798 
16793 
16666 
16881 

isee? 

163B3 
16604. 
16605 

16907 
16666 
16809 
168 lO 
16811 
16812 
16613 
16814 
16815 
16816 
16817 
168 IS 
16819 
16S28 

lssai 

16S22 
16623 

16824- 
108S5 
16826 
16827 
16828 
168579 
16636 
16631. 



16 
66 

CB 

rr, 

28 

04- 

C5 

CC 

a** 

36 

11 

EC 

FF 

iiR 

3C 

JO 

36 

00 

23 

3& 

00 

13 

7E 

FE 

66 

26 

11 

28 

7t 

F£ 

00 



11 

1* 



16B33 
16834 



66 
36 

86 
23 
36 
82 
28 

as 

3C 

4.6 
16 
16 
2A 



16635 


3C 


1&B83 


ifH 


16836 


40 


16884 


3C 


16637 


FE 


16885 


40 


16838 


08 


16866 


23 


16839 


28 


16887 


18 


1884.0 


86 


168CO 


3E 


1664.1 


re 


16889 


2fi 


166*2 


26 


16690 


3h 


168*3 


28 


16691 


40 


16944 


84 


16892 


86 


16646 


FE 


16893 


&& 


168*6 


34 


16894 


7JE 


1684-7 


28 


1G89S 


FE 


16846 


E6 


16896 


09 


16849 


19 


16997 


sa 


1685B 


36 


16898 


pi 


1*881 


17 


16899 


FE 


18662 


23 


16906 


26 


16863 


36 


16981 


aa 


16854 


17 


1698& 


IT 


16855 


C9 


18903 


36 


16656 


IB 


16904. 


00 


16857 


06 


16965 


2R 


16656 


76 


16906 


ec 


168S9 


08 


16907 


40 


16866 


62 


16908 


11 


16861 


A9 


16909 


05 


18662 


08 


16910 


00 


16863 


en 


16911 


19 


16864 


CD 


16912 


7fc' 


16865 


BB 


16913 


3C 


16668 


82 


16914. 


FE 


16887 


CB 


16916 


26 


16868 


65 


16916 


26 


16869 


28 


16917 


05 


16870 


04 


16918 


36 


16871 


CB 


16919 


1C 


it,y/2 


6+ 


16920 


SB 


1&673 


i£ft* 


16921 


as 


16974 


0E 


16922 


F5 


1687S 


2« 


16923 


77 


16676 


Uf 


16924 


IB 


16877 


46 


1&925 


06 


16978 


7E 


16926 


FE 


16879 


FiE 


16927 


34 


16889 


gxj 


16926 


r:« 


16691 


26 


16929 


BE 


16666 


06 


16926 


3t 



16931 
16932r 
16933 
16934 

16935 
16936 
16937 



16941 
16942 
1694,3 
16944 
IB94S 
16846 
1694.7 
16948 
16949 
16950 
16961 
16962 
1&9S3 
16913* 
16955 
16956 
16957 
18956 
16959 
16960 
16961 
16962 
16463 
16964 
1696C 
16966 
16&67 
1&96S 
16959 
16970 
16971 
1697» 
16973 
16974 
16S75 
16076 
16977 
16976 
16979 



B* 

2ft 

ec 

4.0 
11 

BC 
06 

aa 

48 
18 

14 
76 
FE 



20 

CR 
36 
60 
11 
15 



ifcsaat 

l&WB 

1596-1 
1B9BI. 
16866 
16967 
16988 
16989 
16990 
16991 
16992 
16993 
16994 
1S995 
16996 
16997 
1699S 



19 

06 
50 
18 
BF 
36 
18 
22 
3E 
40 

4-e 

40 

86 



5E 

S3 
55 

EG 



7F 
FE 
76 
20 
lit 



17606 
17001 

17002 
17063 
17004 
17005 
17066 
1708 7 
17BBB 
17009 
17610 
17011 
17B12 
17»13 
17014 
17B1? 
17016 
17017 
17019 
17019 
17020 
17021 
17022 
17023 
17024 
17025 

170a & 

17027 
17031? 
17029 
17030 



CO 
02 

40 
?C 
El 
FE 
28 
36 
JC 
11 
13 
60 
19 
18 
14 
36 
00 
FE 
b4 
20 
08 
2B 
7E 
FE 
76 
20 
FB 
16 
68 
28 
7E 
FE 
76 
S8 
02 
36 
34 
EB 
El 
72 
2B 
73 
23 
23 
CI 
16 
C5 

C3 

Fl 
40 



YOUR COMPUTER. APRIL 1983 B5 






SPECTRUM 48K : 2X81 16K 
SIX PART ADVENTURE 







BLACK CRYSTAL 

THE QUEST IS ABOUT TO BEGIN 

The vKflWW ra^-playrg sdvcntur* ten the SPECTRUM/ ZX01 
You (M fttetftw ■ wjurtof . t»P Or vwijpfl rd tw i J c :u w( f t> r.nrf drM} uK 
ihe nn£& ol ereancn to dmimy the BLick Cfynul iiwl defmi |i» 
Lord* a! Cnaoi. HcM vmhm tix pragrjirTO J*> <t land of fabulous 
tttttum jmd mvihic*l mcm«l«n, Jou«1*Y Uiiwh.Ii tho find tff 
Bcroth, oupkwe ihw uatfe of sliadowv detewid into the 
SKkvkUH* Hir, w»reh l<y injmoc* in tNt a** o> Mnrtbul bcvwc 
of und stunts' Confront (He f*e demon m his lemple, btiile 
again*! th* Lord* of Ohm* and vwi your way to she Stack Cfyiufll. 

&y w*'ll*»fl Bi«k Cwt* 1 ^ito ** pfogfo™* we wi p'ovuSe mew 
vifpetv jknd tleuil ilun my oiher Mfv«iiuie lew rt» SincWf 
cpmptilerv 

RcaJ trnw monster thitltes. Superb qraph^rti. SawffiHTie lecture 
All m parts m- tupplxxf iogftnei on ctutth. boxoel mtti 

insliuetxm booklet. 

SPECTRUM 48K: 1S0K OF PROGRAM 

IN SIX PARTS - ONLY D,50 
ZXS1 16K; OVER 100K OF PROGRAM 

IN SEVEN PARTS - ONLY £7.50 

WHY PAY MORE FOR LESS OF AN 

ADVENTURE 




To CARNELl SOFTWARE OtPT 2. * STAUNTON RO, SLOUCH. SL2 f NT. 
PtWle send me: Buck CtVSHl 'tir my. 



Specif um 48K.. , 
ZXB1BK.... 

I «tdos# 3 cfwqua/pocud BK»*f I MOW* !0 C**HI Scitwwo! fat C 

NAME 



f7 50 
17 50 



A11DHFS5 



TRADE ENQUIRIES WELCOME 




;{; 



mimimt: "tl ill "*■« 

■ ««« ;;; ;;; :;:;:: 
Hiii" :;!;;£; ::::;;! 



6f t 



Tit If* JTl tit 



........... ....... 



FOR THE C.B.M. 64 

IN MACHINE CODE 

e.pp 

A, PLANE LANDER ....8.00 

B, NIM AND LINE UP 4 7.60 

C, FRUIT MACHINE .... 5.70 

D, HANGMAN WORDS & MATHS ........ $.50 

E, SPACE NUMBERS 7.00 

F, BATTLE SHIPS , 7.50 

G, PROTEUS CHALLENGE 8.00 

All programs available on 5 14 ins. disc add £4.00 
All progrms on one disc for £45.00 

SPECIAL SERVICE only £8.00 per program 
Your programs compiled into fast, efficient 
machine code. Send your programs on tape for 
speedy service, compiled programs sent on new 
tape. Also available for 5% ins. disc users £12.00 
(max. no. of errors de-bugged 5, programs may 
not contain any machine code routines already). 
No liability accepted for tapes damaged in process. 
Send SAE for details. Trade enquiries welcomed. 

Make cheques or P/O payable to: 

PROTEUS SOFTWARE, 8 GLASGON COURT, 

GRANGE ROAD, LONDON, W5 5QR. 

orders usually despatched within 7 days 

of receipt of order, for use with CBM 64 only. 

e = educational 



EDUCATIONAL COMPUTING 

or the 




itrongly 

ndaf " 



ZX81 




^.k Oil l™ 



fecOmmendad by 

| rdu clonal | Fifty high- quality programs to turn your ZX81 
i_ f^] hoM|i ** _j Or Spectrum into a power tut educes tonal tool. 

And you don'j *V*n need to kttowr propr&nirifg. 
Tttmem *t* &tmr lfi*l/u£tt>&n* tot/ ottnlf of rjpj 
A MfM M4Jpnetf to faOtyerrt ttiM A pitcnc* 
i*« promof imernina ttvouatr kttmmCHO* * Ji i cpw r y. 

Includes - 



TORTOISE 

' r- ■ i ■■ — 

A simplified 
vtirsiOn of the 
tampus Turtle 
oi liUJWy 'M I pfograirmie 

CQOED MISSILE 



SPECTRUM 



AW programs 
tit tK 

Cr**tiv* use 
graphics 



My innOvetive 
ideas 



fully documented 
Includes many 

games 




Combiner the 
fun of arcade 
games with 
fewn in a 

£5 "95 only 

ptp*'0*c* no poje* 

Gfapfi-ptanw • Histogram • 5impfl~$p«ll* SkticMu^j • Times ■wbl( • Sets 
SefM-quw • Xt- cooitjrnaies • Count • Equanons • flieas # Gueu-a-Votur* 
Angles* Ujjiuirs- Down suits • Mus«-not« # S« saw • Wipe-cui •Sprtl 
Tcmpeiiiur* • Clue* • Money • Snake C^\l 1^^ A QC 
MaslermrrnJ* Number shooi • +26rnaft bUUvMKC 



To 



| Plaa&e send n>e COpte? Sducare's S0j 

I 



IEOUCARE [| fine lose cheque postal order for £ 
139a S(oane St u,.,- 

L ^ d °" u^l~ 

SWIX SAY I AddresS 



Lai your child OeriBlit **r|y - 5«ifl now 



B 6 VOUR C OMPU t ER. APRS. 1 98 3 



Introducing 



©so 



?vf ll&£ 






cfitss 



THE BEST at £7-95 

Guaranteed able to beat Sargon II 
and all other Spectrum chess programs ! ! ! 

• Six levels of play 

• Plays a variety of openings e.g. French Defense, Sicilian Defense, Ruy Lopez, 
Queen's Gambit etc. • Self play mode • Analyse mode 

• Enhanced end-game play •Recommended move option 

Proof of the superiority of SUPERCHESS II is available in the form of listings of 10 
consecutive games played against other well known Spectrum Chess programmes. 
SUPERCHESS H 8 wins, Spectrum Chess 1 win and 1 draw. The listings are free 
with each program or 40p on their own. 

Available only from the address below - dealer enquiries welcome 




••ORIGINAL SUPERCHESS •• 
The Cheapest 

10 levels of play: recommended move option, 
substantial 'opening book' e.g. French Defense, 
Queen's Gambit, Ruy Lopez etc: Self play feature: 
analyse mode. 48k Spectrum E4.95 

16kZXS1 £4-95 



ZX DRAUGHTS 

The game for everyone, played at level O It replies 
immediately, can you beat it at level g? 
Draughts is an ideal game to apply tree searching 
techniques to. Our machine cod© program analyses 
each position in depth making it a formidable opponent 
Choice of colour and search strategy. 10 levels of play, 
at level 4 {response time - 20 seconds) it beats its own 
programmed 48k Spectrum Ed. 95 



•• BACKGAMMON 

(mm 
[mm 

Play this fascinating game of skill and chance. High 
resolution colour display with dice roll. Can be used by 
expert players and also has documentation to enable 
beginners to learn the game. 48k Spectrum £5.95 



UK Prices include post & packing. Despatch within 43 
hours ot receipt of order 
{For orders outside UK add 80p for postage). 
Send cheque or postal order to: 

CP SOFTWARE, Dept.YC, 17 Orchard 



••SPECTRUM SPEECH •• 

Yes it's possible! Software driven speech from the 
Spectrum. Simple to use in your own programs. Each 
cassette comes with user documentation and 
demonstration program. No extra hardware is required. 
Uses Spectrum speaker and top 32k Ram. 

SOFTALK I: 'Multiwords" 70 plus words, numbers 
zero to million, plus, go, limit, right, 
great etc 48k Spectrum €6.95 

SOFTALK II: 'Spacegames' 80 plus words, numbers, red 
alert, torpedoes, phasors, bearing 
south etc. 48k Spectrum £6.95 



•• BEEPER AMPLIFIER •• 

Boost your Spectrum's beeper. This neat amplifier, with 
volume control, plugs directly into the Spectrum's EAR 
or MIC socket using the tape lead. NO OTHER 
CONNECTIONS NECESSARY. Powered b^ a PP3 
battery (not supplied) it doubles as a radio when not 
used with your Spectrum. £5.95 or only £4.95 when 
purchased with a SOFTALK program. Please add 35p to 
cover p&p. 



••SPECTRUM ASSEMBLER •• 

An essential aid for m/c programmers. User 
documentation supplied with each cassette. 

16k and 48k Spectrum £4.95 



?"* tori's 



O/v 






3 0th 



Lane, Prestwood, Bucks. HP16 0NN 



PROGRAMMERS - TOP RATES PAID FOR HIGH QUALITY SPECTRUM 

STRATEGY GAMES AND SPECTRUM FORTH. 

SEND YOUR MATERIAL FOR EVALUATION AND PROMPT REPLY, 



YOUR COMPUTER. APRIL 1983 37 







2 GO SUB 30es 

3 GO SUB 6000 
S LET Sl=S. LET £2-0 
S REM 
S REM 2 Lines O *" 32 Gi 

lg PRINT AT « 




•.',■:■;->,; 




' ''■'■'■:V : :';', 




a* REH 

t5 REM 2 Lines of 

^S^prtnt^^^^^ ^^II 



32 Graph i c fi 



4-4 REM 

4-5 REM Graphic 8, 30 Graphic b 

Graph i c s 

50 FOR f =£ TO 19: PRINT RT F , 

"■miiiiiniiiin!ii)niiiin 



dJ* 



60 NEXT f 

70 LET X=4; LET y =10 
80 LET a =27: LET b=10 
00 LET d=£. LET c =4 
95 GO TO 100+60* fRND < -Si 
110 LET a*=("l"- RHD IN 6J43S *> 2 
55> + l"*2" AND IN B*510=2S3J + { " 3" 
AND IN 6S022<>255J + (*+" RNF> IN © 
4.510-2544 

120 IF LEN a*-l THEN LET d =\>Ri- 
as 



125 LET X~X + fd =2Ji - Id 
y + (4=3) - Cd -1) 

126 IF SCREEN* (y,X* 
O TO 2000 

130 PRINT RT y,*; BR 
C1J ■"■*■: REM Gfaphit 
14-0 IF SCRE-EiNS iy+1, 
PRINT RT y+l,Xj PfiPER 
;"«": REM Graphic ft 
14-5 BEEP -01.0 
160 LET a*=f f "l" RNP 
55)+t"3" HND IN 57342 
AND IN 4.915So255^f 
734-2=253? 

170 IF LEN a$-l THEN 

175 LET 3=a+tC-2>— *t 
b+l c=3J - f c=U 

175 IF SCREEN $ ( b , a ) 
O TO 100B 

ISO PRINT RT b,a; BR 

c2; "|" : REM Graphic 

130 IF SCREEN* fb + 1, 
PRINT RT b+l.a; PAPER 
, "M" : REM Graphic R 

195 B^^R -01.10 

200 GO TO 100 



= 4-J ; 



LET y m 
THEN G 



XSrJ-FT 1 ," XNI< 
ClJ INK Cl 



IN 614-301 >2 
=254-i * {"3" 
4-" ftwcr* IN 5 

LET C =VRL 

-4 J : LET b^ 

< > " ** THEN G 

IGHT 1; INK 

a 

al ='"" THEN 

C2; INK C2 



68 YCMJR COMPUTER. APHIL 1983 



GAMES 




Force your opponent into a 
corner — that is your 

sm^^^..^,^. goa' in this 

^interactive game 

by Andrew 

Foord for the 1 6K 

ZX Spectrum. 

Two people can 

play simultaneously 

using the keyboard — 

instructions are shown 

in the program. The 

players shoot along the grid 

leaving a trail of deadly 

orgone energy in their 

wakes- This manifests 

itself on the screen as a 

wall. To survive you must 

force your antagonist to 

career helplessly into either 

your wake or his own: 

both will prove equally 

fatal. The program gives a 

view of the action — 

looking from an angle of 

45° — by using Bright to 

make the top of the trail 

brighter than the front. 

The player to win is the 

first to achieve a score of 

10. Different trace 

elements can be injected 

fnto the energy-conversion 

cycle of your overlander to 

alter the colour of the 

exhausted field of primary 

energy you leave in your 

wake. You can have any 

colour you want as long as 

it is not black. To make 

the game really confusing 

the two players can even 

be the same colour. 



100© 


PRIMT fit h,a; FLASH 1; " " 


2010 


LET sl=sl+i 


102© 


GO TO 3000 


2S0S 


PRINT BT y,x; JF^RSH 1 ; " ** 


2010 


LOlI 52-52 + 1 


3000 


FOR f-30 TO 30: BEEP -tfsal^f 


: NEXT f 


3010 


PRINT INVERSE 1 : RT 9,11; "Pi- 


aye r 


le ";sl 


3020 


PRINT INUERSE 1 ; RT 11 # 11; ^n=> 


Layer 2 .- ";s2 


3030 


FOR f=S0 TO 30 STEP -1: BEE 


P .001, f : NEXT f 


303S 


IF sl>9 OR S2>9 THEN GO TO 


4-00© 




3340 


XF XNKEV$<> tt " TH^H GO TO 30 


4-0 




3050 


PRINT RT 20 ,3; TNUH&^E. X; wr f* 


RES5 


RNY KEY TO CONTINUE" 


3060 


XF INKEYfO"" THEM SO TO 10 


3070 


GO TO 3eS0 


4-000 


PRINT FLASH 1_; RT 13, 10; "PO* 


YER k 


"; Cs2 = 10> +1; " UIH3" 


4018 


INPUT "Another gc? "; LlNe 


0I Hi 

4020 


IF 3$="" THEN GO TO 4010 


4-030 


IF 3$tl><>"n" THEN RUN 


4-0*0 


STOP 


8000 


BORDER S: PAPER S. INK ~F- C 


i_S 




3S10 


print "This is - - 


3020 


PRINT TAB 13; "CHfiSER" * TAB 




HMDREU. FOORD" 


SS30 


PRINT '"The object of dHRSE 


R is 


to force the other pisyer in 


to a 


wall." 


5040 


print * " Each player has a 


chaser which Leaves a. trails tJ^e 


chasers tan not stop until one 


is destroyed*" 


3S50 


PRINT 'Tf*e 12.; "CQ^FTROL-B-- 


8051" 

D 

©055 


HEitt ^-Graphic C., v-Graphic 


PRINT TfiB 14;"" < > ^~ 


3060 
R 

8070 
i_" 

3050 


PRINT "Player i; = m U 


PRINT '"PLauer 2; OP 


PRINT *TRB 14-;' ,J - < > ■*-*< 




INPUT "Players l cot&u r ? tl 


TO 7> "; cl 


8118 


XF C 1 < 1 OR Cl>? THEN GO TO 


3100 




3120 


INPUT "Players 2 coUbf? fl 


TO 1 


? J "; c2 


6130 


IF C2<1 OR C2>7 THEN GC* TO 


3120 




3140 


RETURN 


3000 


FOR f=S TO "7 STEP 2: POKE U 


SR "a" + f,170: POKE USR "a*" + F + l,S 


5 : NEXT f 


9010 


FOR f=0 TO S; POKE USR ^&" + 


f,12^: HEXT m POKE" USR " W r ^~7\S^ 


3020 


RESTORE : FOR f =0 TO 7: REP 


D 3 : 


POKE USR " c ■" + F f a r POKE USR 


"d"-^ 


';f,3: NEXT f 


3030 


DfiTR 8^3 f 5, 213 j.34 .0,0^13 


3040 


RETURN ■ 



YOUR COMPUTER, APRIL 1933 89 




From Scotland's Capital comes quality software lor ihe 



ZX Spectrum, VIC 20 & now also Dragon 32 



The Quest 



(48K ■ Spec trum; Dragon 32) 
{Qrti- ni ihe moit exciting ariueniure 
qames currently available). Fight your 
uvuv iino the depth*, of the complex in 

ycimr Qui-'.l for the Holy Grail. DiSCOWr 

bold and Precious stones, buy weapon.* 
ind Magic warn from a trader Battle 
wpi'» ■> i it ol Ihe many Monsters. Up lo 
l c >00 local ions may be searched in the 
enurse of a flame. Full sound effects and 
s.jvf qame facility. Only £500 

Suit Trek 



urD Star lighter 

<4SK - Sp*cuum, tSK - VIC 20; Dragon 32) „-„ _ «-„.„,_, 
Make your way through (he under " D * ^("^"umt 



ijiuunil labarynth m your search lor tbe 
dreaded Orl>. which yog must destroy. 
Encounter many Monsters, discover 
Treasure and try to rememlier your 
route so that you cm gel out again. Full 
sound effects and save game laciltiy. 

Only lb 00 * 

NEW 3D Maze 



n . rt ™i (4SK ~ Spectrum; Dragon 32) 

<;,*¥*■ game l.icihry Only £5.00 . 

1. EMCiltnq 3 Dimr-itMiirt.il Mri/f Gam*-' 

Sf.nrh tttt ihi 1 J l.ihylous iti>,i<sui<>$, ihnn 
I16K Sp«rrum,8K - VIC 20; Dragon 32) milll ,. yuLt , Wly | wct |(( (ht . ,.,,, Tl(w 



An action, full-colour, graphic machine^ 
code. Space battle with devastating 
explosions. On screen scoring and high 
score kept. The longer you furtive The 
more difficult il becomes. Only f S 00 
Games Pack {Unexpended VIC 20! 

Alien * Road Race * 

The Istarwl " Pnrtlurin * 
Only ES 00 



'din ftn 1 CS.il.ixy trorn Ihr» Klint|on<> usmq 

vfui ii«pnMirfl phasers and phcuoii 
r<trpruVH Automatic shnri range vcan, 

' ■ ii i» ,' map iintf Si.ii n.isKt 

full itHiivd #?lleci> itnd 10 level* "' 
itifficuliyi Only £5.00 



yovrsfM uwdi ■>«■ On Sci'tii Cloth 
Bur 8>'kv."f rtw ireogurn »<> net 

alWHiyv in ihir uiu1i> looinimi 

Only £5 00 

OtMli'r-. Aiii.h Iivi'UisiiiijiiI', 

Slir-H II nisi Si VII .-'<> [II <i |i inimi '. 




ALL ORDERS DESPATCHED BY RETURN «.i»i«i 



3*>% R«ry,illii-s P,nd 



I enck>s« a Ctvqu&t 



Name 

AfJfJreB*,. ____ 

Am pr.ee* IndUM P4P*nd VA.1 
IMPWCT SOFTWARE 
70. RefltWO Avenue, 
tDlNBuftjM£Ml3cew 
JEL 031 -441-^5 J" 



TheCM*i<C*O0rP 

CXpCtSCOl D 
SrarT**n<t5 00) D 
Piaace «■*> machine lyj» 



3-0 Mj»j« fcs fX>! D 

st^igmeftcsoo) O 
G*n« PfeMCSCCI D 



IMPACT SOfTWEAR 

fw S*"""^i C«"!» <M <u> l T mi r »i mr iv 



Destroyer* 16&4SK 



ZX Spectrum 



New cuid original anode gain* "i real htne. w" 1 "-"" m high 
ipred mothint cade with ht-r*i grophm. Full ioTciui and 
itvnd e ff •< 1 1 . T* tt y g l»' ikill againtt the switonie gag 
varying firepower i>( the djffc'«ni waves Q l i. he 
Dr»trgy. r ». M»gn H«* W»H*. £ 6"50 



ZX TREK 



48K ZX Spectrum 

Firil qi>el.iy Hai ireb gome in r#ol lim« wilK hi<*r«i 
gfopflitr pJui (On vi on< on ictr" ditploy of galaxy mop 

leng ranfj* nan, and iiaiwoi rtpori. 

O v • r I>tn1f c • m a n d * with full (Oloitt and 

**wnd («*<••. 

T hi» ggim« prtvitlai a real choilenoi-. 

Kn ihe ZX Spaxfrum gome plovtr. 




■ 



C 6-50 



IMPACT SOFTWARE 

70 BtD'OKD A-r 

£ D ' N B l,. 9 C " 

f H 13 l)(H 

Til 03" 14' 411 7 



OfSTHO V t BS 



in 1REK 




Business Bank Account 1: this program enables you to make 
debits under 1 1 subheadings. Statements include totals of all sub- 
headings. EH 75 

Business Bank Account 2: with IB subheadings and standing 
orders. El 0.75 

Sales Day Book 1; for all your invoices, this program will enable 
you to prepare statements of outstanding invoices. Program witl 
also calculate VAT. E8.75 

Sales Day Book 2: with many extra facrUties including toiaJs of 
past 12 periods. €10-75 

Sales Cash Book: for retailers program calculates VAT and 
denotes met hod of payment . D3 r 75 

Purchase Day Book 1: keeps a complete record of all your 
purchases under 11 subheadings. The program will also calculate 
and deduct VAT. £8.75 

Purchase Day Book 2: with many extra facilities including totals 
of past 12 periods. f 10. 75 

Quarterly Analysis: quarterly totals from Bank Account, 
Purchase and Sales programs can be analysed with this 
program . £4.75 

• Ail the programs have full search facilities • 

Business Pack 1: incl. Bank Account 1, Seles 1, Purchase 1 and 

quar ter ly a naty sis progra ms £25. 00 

Business Pack 2. incl. all 4 programs £30.00 

Please specify memory size when ordering for your 

ZX81 or ZX spectrum. 

ALL PRICES Includa VAT pO»t U pJtheCjina for dnrs.l» und SAE lo 



TRANSFORM LTD 

41 Keats Ho Porchester Mead Beckenham, Kent, 

Tel: 01-658 1661 



90 YOUR COMPUTER. AFHiL 1 983 



J. h. GREVE 

TERPRISES LTD 

V ,.. is a new company, from J.K. Greye, set up 

(^ . specifically to bring you High Quality/Low 

Cost games lor y°u r Sinclair ZX Spectrum. 



THE 

AtKCAOiAti 

4 Gomes plus Menu ' 




for th 
SINCLAIR 



6/48k 
PECTRUM 



only £4.95 incl. 

^iHKide£ 

Invosion ■ Kamikaze 
Minefield • UFO 



Games a a" 






tre for £5 + .each 



The ARCADIAN 
includes games to suit all ages, from 5 to 105 

INVASION: Our version of the Classic Arcade Game, 
surely one of the best around. Includes Full Colour High 
Res. Graphics, Sound and it's incredibly fast at the end. 

KAMIKAZE: If you like Scramble, you'll love this. 16 
levels (long ones at that}, of tortuously twisting caverns. 
Missiles. Starmincs (which move in between games, so 
it's never the same next time around). Bases, Fuel 
Dumps {watch you don't run out of fuel!), and two 
speeds {difficult and impossible). Definitely a game for 
those amongst you with a suicidal tendency, when 
playing games, because you can score even when you 
crash! (If you can make il past level 1 8, write and let us 
know, 'cause that's as far as we've managed!). 

MINEFIELD: A totally new game. In which you have to 
lay mines in a forest Sounds simple doesn't it? But, 
once you start, you can't stop and there lies the rub {or to 
be more exact the explosion'). Guaranteed to get your 
fingers in a twist! 

UFO; Dodge the Asteriods, blast the Alien Craft and 
work off your aggressive instincts on the keyboard. Gets 
progressively more difficult the longer you last I 

All of these for only £4,95, can you afford 
to miss out on this one! 

;Wf 

Send your order to J.K, GREYE ENTERPRISES LTD 
16 PARK STREET, BATH BA1 2TE. 

Please send me copies of "The ARCADIAN" at £4.95 

e8Ch ' t0; Name 

Address. 

Postcode 

I enclose a cheque;P.O. for £ ,, 

made payable to J.K. GREYE ENTERPRISES LTD. 

All So(!*Jre sold subjet! to [he condition (hat Hiring, LfrWJing, 
Unauthorised Copying or Rasals is, Strictly Prohltriiad. 

toadeTexkot ctguirieswelcome~ 

PROGRAMMERS! Do you think you can write briltianl 

games Software for the Spectrum? 
If so, contact us and well market it for you. If you doni 
think your games are the be3t around, try the other 
Software Houses, because we will only sell the best! 




Outstanding Features 

• Self centring stick. 

• Super strong nylon and steel construction, built to last. 

• A total of 8 directions plus 2 large fire buttons. 

• Arcade proven moulded leaf switches ensure incredible 
reliability. 

For ZX Spectrum complete with self contained box 
interface which simply plugs into the Spectrum expansion 
port (with or without printer) only £25.00 inc. VAT. 
For VIC 20, Atari 400 and Atari 800 only £ 16,4* irtc, VAT. 
Full range of software available, details on request 

SOU= UK DISTRIBUTOR 

KEmpsron 

"^ MICRO " ELECTRON ICS 

1 80a Bedford Road. Kempston, Bedford MK42 8BL 
I wish to orden 1 

I 



Quantity 


kt-jr. 


Price 
















Pose & Packing 

Total {VAT inouv ve) 


CI. 00 







Cheques/Postal orders should be made payable to 
Kempston (Micro) Electronics 

Name 



Address . 



Post to Kempston (Micro) Ctectronics, Dcpt 

180a Bedford Road, Kempston, Bedford MK4Z 8BL 



YOUR COMPUTER, WRU. 1993 91 




OF THI 





PLEASE SEND ME it 

PLEASE SEND ME .*.....»....... $t . . ■ * .■..■■.<■* ■ 

I PLEASE SEND ME ®< . . 
PLE ASE ADDON 5 Op for P&P 

Ilencloit chequer P.O. payable to m 

DKTronic$tot*l ordafcrt my 

Accent Barclaycard 

NAME ... ADDRESS 

SIGNATURE 



CREDIT CARD SALES LINE 

(0493) 602453 (24 hrs) 

Quoting your Access or Barclaycard number 

DK Tronics software Is also available from alF ( 

good software outlets. 

3D TANX- Pit your wits against the enemy Tanx, This is a full feature game with 
fantastic 3D balistics. ONLY £4.95 

3D SPAWN OF EVIL— Eliminate the spawn before it matures to full attack potent^ 
The most spectacular 3D space game ever written for this I&K SpeCtfum. ONLY £4.9 i 
CENTIPEDE— Shoot down the ever menacing Centipede before it shoots you One f 
the most addictive games for the Spectrum ONLY £4.95 

For more information send 5.A.E. for our full colour brochure. 




* 0. 



m 



rK 




9 Pfc3 



Sal 



K2»fF*Cr 



■ ' ' ' 



% 



X 



: 



UCTATOR— Can you Sufvrve as Dictator? A complex 

r»d entertaining simulation adventure featurrng easy 

Deration and excellent use of graphics ONLY €4,95 

lETJEOROfD*— The hesr Spectrum version of mis 

spufar arcade game ONLY £4.95 

DUND FX — Even the begrnrwr can use this 

nstaitic program to create and infinitely variable 

nount of machine code sounds ONLY £4.95 

IS ASSEMBLER -A fast machine code disassembler 

r use on the ASK and I6K Spectrum givmg full 

ilOur output CO the screen ONLY E4.95 

XED (TooJkitJ— A powerful edrcor for use on trie 

bK and 48K Spectrum, it creates several useful and 

ne sawing features ONLY £6,95 



4 




23 Sussex Road, Gorfeston, Gt. Yarmouth, Norfolk. 



■uko 




LmJDC§[?(o) 

— (am 

FOR OWNERS OF 

IBo (Mi 






IAjU o l! 

ramnr 
Mill 

MICROCOMPUTERS 



Buying software for your computer is a gamble. Apart from 
the occasional review and, perhaps, a recommendation from 
a friend, you have precious little information upon which to 
base your purchasing decision. 



Advertisements and clever packaging can make the the 
worst programs appear tremendous. It is not until you have 
'gambled' your money that you discover how good they 
really are. Some arc only slightly different to others you 
may already own; many are not as good as you would be 
entitled to expect; and others are just a complete waste of 
money. Of course, there are some excellent programs 
around, and many more appear month. Now there is a safe 
way of finding out about them- 



- free membership - 

THE MICROCOMPUTER SOFTWARE CLUB was started 
to make software purchasing easier, cheaper, and less risky. 
Membership is completely free of charge, as is the monthly 
Newsletter. Every month members receive full details on 
the best and latest programs available for their computer 
and, simply and confidently, are able to order any of the 
programs they choose at substantially less than normal 
prices. 



large savings 

on top software 

All programs are, at least, 10% cheaper than normal and, 
each month, the best of the most recent software is made 
available to members at 20% less than normal. Postage and 
packing is free on orders of two or more programs for 
delivery within the UK; ordering and payment are simple, 
and quality is guaranteed. 



no obligation 



Members are not obliged to buy a fixed number of programs 
from The Club. They buy what they want when they want, 
Whether it is one program in a year or one a month, they 
know that when they buy from THE MICROCOMPUTER 
SOFTWARE CLUB they arc buying the best programs at 
the best prices. 



— free Newsletter - 

Our latest Newsletter offers programs from most leading 
suppliers * and from a few that, perhaps, you do not yet 
know. A program has to be good, very good . before it is 
recommended to members. It also has to be reliable and, 
even before the members' discount, it has to be good value 
for money. Subject coverage includes adventure, arcade, 
education, strategy games, household applications, family 
games, business, utilities and programming aids. 

Remember, membership is completely free of charge and 
you are under no obligation to buy anything from The Club 
unless you really want to. If you own or use a ZX8 1 ( 1 6K), 
Specirum( 1 6K or 48K), BBC (A or B), Dragon 32, or VIC 
(expanded or uncxpanded), you should join THE CLUB. 

THE MICROCOMPUTER SOFTWARE CLUB 



P.O.Box 166, Oxford, 0X2 9 BJ, England. 



Free membership application 



Please accept my application and enrol me as a 
membciafThe Microcomputer Software CI Lib. I 
understand That membership is free or ehatge. 

As a member 1 will receive the Club Newsletter 
free of charge and will be entitled to benefit 
from any savings offered to members on selected 
programs for microcomputers. 1 may cancel my 
membership at any time- 
When completed, return form to:- 



NAME I I 
ADDRESS I I 



CITY 

POSTCODE 



1 



1 



II I I i I 



I I I f I I 



M I I I 1 I 



I I I I i I 



I I I I M I 



1 



I M I I I I r M I I I t II I I 



I I II I I I M I I I M I I I I 



I I I I I I I I I I I I I I I M I 



I M 1 M I I M N I I I 1 I I 



I I M I I I AGE (If under 18) |_L 



THE MICROCOMPUTER SOFTWARE CLUB 

P.O.Box 166, Oxford, 0X2 9BJ, England. 



COMPUTER MODEL I I I 11 I I I I 1 I COMPUTER RAM LJLJ 
SIGNATURE 



94 VOUR COMPUTER. APRIL 1983 



A VARIABLE is a named memory area inside 
the Vic which can store varying data. This 
data can be in the form of numbers or 
characters. If you can remember algebra at 
school it typically looked like 

x+2 = y 
where x and y are variables. Obviously The 
value oT v will vary as the value of n varies. 
There arc two types of numeric variables used 
by the Vic — integer and floating point, which 
is sometimes called real. 

Integers ate whole numbers with no decimal 
point and the Vic can only deal with them in 
the range 327$$ to + 327$7. The Vic will 
assume that numbers arc positive unless you 
tell it otherwise- Examples of integers are: 
r, 100. -320QQ, 990 

Floating-point numbers can have a decimal 
point and cover a much wider range than 
integers. Floating-point numbers can also be 
expressed as a mantissa with an exponent, 




Savour Clive 
Finn Is' recipe for 
slimmer and faster 
programming with this 
first course in Vic variables. 



VARIABLES: FIRST 

COURSE ON A PLATE 



Simply, this means that the number 
I2K.567S can be expressed as a mantissa of 
L2M5678 and an exponent of 3, where the 
exponent means "Times 10 to the power of 3", 
or in this case 1,000. This would be entered 
into the Vic ay 

1.Z345678E3 
This might seem an unnecessary complication 
but in, fact it makes the entry of very large and 
very small numbers easier. 

For example the number 1,000,000,000.0 in 
mantissa and exponent form is 1E9 and the 
number ,0000123 will be 1.23E-5. 

A negative exponent can be thought of as 
"move the decimal point to the right", 
whereas a positive exponent means "move the 
decimal point to the left". On these two 
examples wc moved the decimal point nine 
places to the left and ended up with an 
exponent E9,, and in the second case we moved 
it five places to the right and had an exponent 
of E-5. 

The range covered by the Vic is from 
* 1 .70141 183E+ 38 to * L93873588E-39, and the 
Vic works to nine digits of accuracy. Try some 
number!, outside llib range jnd sec what the 
Vic makes of them. 

Bui how does the Vic expect you lo define 

variables? What is the syntax for describing a 
variable? The computer only acts on one, two 
or three significant characters of the variable 
name — although variables can be much 
longer. The first character must be 
alphabetical. The simplest variable names will 
be just one alphabetical character — for 
example, A 

In reality the Vic sees this as two characters, 
one alphabetical, the other a "nothing" 
character, thai is ASCII or null, Try the 
following: 

PRINT CHR$(65) 

You get the letter A — correct? Now try 



PRINT CHR${65JCHfr$l66t 
You get AB. Let us, introduce the ASCII or 
null character in the middle to see what it 
does. Tvpe 

PRINT CHR$(65K:HR$I0)CHR$U36I 
The printout reads AB again — in other words 
the ASCII null is completely ignored. So when 
wl define our variable names as A, I or X the 
Vic stores AO, 10, XO. 

Ifyou decide to use a second character this 
can be alphabetical or numeric — that is A 
through to Z or through to 9, so that AA, 
A9, XA, XI are all valid names. 

Our third significant character can only be S 
or %. These characters define the type of 
variable that the one or two preceding 
significant characters represent. 

Any variable followed by the % sign means 
that this is an integer variable. Any variable 
followed by the S sign is defined as a string 
variable. Any variable not followed by % or S 
is by default a real variable. Examples or valid 
variable names arc 

A AA A1 Z5 for real 

1A% AA% A7% Z3% for integer 

AS AA$ A1S 29$ for string 

Note that you can use, say, A, A% and AS in 
one program and the Vic wilt quite happily 
differentiate between them — it sees them as 
three quite separate variables. 

Where possible try to pick variable names 
which mean something to you and relative to 
the job that they are performing. There are 
traps for the unwary, through. Say you are 
using the variable CO. There will be a hidden 
syntax error in the following apparently good 
line: 

FORI = 100TOCOSTEP-1 

The problem? Vic sees the CO of the variable 
and the S of Step as Cos which is of course a 
Basic function. 
The cure? Put a space between CO and S or 



find another variable name. What is wrong 
wilh C on iis own? It will save you two bytes 
in this instance alone. 

In some cases it mighi be more convenient 
to use whole words as variable names instead 
of just one or two characters. For example, if 
you are writing a program to help sort out 
your home finances, variables such as Interest, 
Balance, Debit mean far more when working 
through your listing than, say, Id, Ra and Dc. 

You do not often get something for nothing 
though and this is no exception. You gain in 
program clarity — you lose in using more 
memory to do the same job. Every time your 
program uses, say, the variable name Interest, 
it needs eight bytes of memory to store it — 
one byte for every character. So the difference 
between using In and Interest is six bytes for 
each time it is used. 

Integer variables are quite literally a waste of 
time and effort. As you will see later all 
numeric variables — forget about Strings for 
the moment — are Stored as float ing-poirtt 
numbers. Thus when we ask the Vic to 
perform mlegci aisthmeiK as iollow.s: 

it first takes the floating-point contents of Y% 
and converts ihcm to integer, then it takes the 
floating-point contents of Z% and converts 
them to integer, adds these two integers, then 
converts from integer to floating point and 
stores the contents in X%. Not only arc you 
wasting time while the processor performs 
unnecessary tasks, but the % character uses up 
one extra byte of memory every time it occurs 
in the program. Tails you lose, heads you 
cannot win. 

This does not apply to integer arrays. 
Significant memory saving can be achieved by 
defining an array as m integer instead of real. 

We saw earlier that you cannot use Basic 
(continued on next page) 



YQURCOMPUTEft, APRJL 1983 95 



Address 4096 — r 
Address 7679 — , 

Memory map. Variables are stored km 
memory, and they are immediately to/ton 




BASIC 


+ 


variables 


+ 


arrays ^ 


free memory 






String 
data 


t 


nodiateiy following the end Of lf>e Basic 
ted by the arrays. 


program in 



(continued from previous page/, 

command words or functions as variable 
names — Tor example Cos, Sin, New, Print 
would all be Thrown qui as syntax errors if you 
tried 10 use them as variable names. There are 
three other reserved words which you cannot 
use as general-purpose variable names because 
they arc already used by the Vie for specific 
variables. 

$T — short for Status — is used 10 monitor 
input-output functions to the scrccm cassette, 
keyboard or serial bus. 

TI is used fur ihc real-time clock . This is 
updated every 0.0 lei seconds by an interrupt 
routine. 

TIS is a string variable of six characters 
length and it will return a real time in the 
format HHMMSS. It may be initialised — set 
to zero - easily by TIS- "000000". 

So now you know something about real and 
integer variables, but what is the string 
variable that keeps popping up? 

String variables are used to store not 
numeric information, like real and integer 
numbers, but any of the 256 ASCII characters 
available on the Vic. Thus whereas the 
virijble A may contain 1.2345, the variable 
AS may contain the word computer. String 
variables art written to — filled up — in the 
following manner: 

AS- "COMPUTER" 
The contents must be framed by the quotation 
marks Shift and 2 on your keyboard. 

String variables are not restricted to storing 
the letters A through to Z, but can store Vic 
graphics and control characters as well. For 
example try the following routine;- 
10 LET AS = "<etear scurcnl" 
20 PRINT A* 
where {clear screen) is the Shift and Clear 
Home. 

If we Run this routine the screen will clear 
just as if we had typed 

PRINT "(dear screen)" 
Note that the Let in line 10 is optional in Vic 
Basic. Line 10 could have been written as 
10AS ■ "(clear screen)" 

String variables can be up to 255 characters 
long. This, at first, seems rather difficult to 
achieve as the maximum number of characters 
that the Vic will accept for one line of Basic is 
88, and this must include the line number 
itself. We can achieve long string variables — 
if we really want to — by the process of 
concatenation of variables. This is really just a 
complicated way of saying adding together of 



"string variables. For example, the program 

10 As - "YOUR" 

20 BS- "COMPUTER" 

30 CS-AS + BS 

40 PRINTCS 
produces the result 

YOURCOMPUTER 
CS has effectively taken Ihc contents of AS 
{Your) and has joined on the contents of BS 
(Computer) to form the longer string. 

Using the CHRS command other characters 
may be added to the string. For example to get 
a slightly belter format to the result we can 
amend line 30 to read: 

30 C$ = AS+CHR$I32I+B$ 
-which will give us 

YOUR COMPUTER 
Character 32 is "space" in the Vic. Another 
way of achieving the same result here would 
be lo use the construction 

30 C*«A* + ""+B$ 

Try different combinations yourself, Use 
the cursor keys and colour characters inside 
string variables and see what results you get. 
Try to make a string variable 255 characters 
long by using concatenation and discover the 
error message that the Vic will print if you 
exceed this number, 

It is also possible to perform comparisons 
between string variables by using the 
following format 

IF AS = B$ THEN etc. 
Of course when it comes to operating on 
variables there are far more operators available 
for the numeric variables. One word of 
warning, though: if you want, say, the square 
of variable A, it might" be tempting to use 
exponential ion of the form 
B-AT2 
However, whereas this will give you the 
correct result, if is a very slow operation in 
Basic and you would be better advised to use 
the less impressive but faster contract 
B = A " A 

So now we have a grasp of the different 
types of Vic variable and how to use them. But 
how does the Vic store these variables? To 
answer that we must first look at the memory 
map. 

In an unexpanded Vic, user memory starts 
at address 4096 and finishes at address 7679. 
Addresses 7680 to 8 19 1 arc the screen area and 
thus the total RAM available is 4K of which 
r 5K is for the screen leaving the infamous 
3,5K for you. To be fair, the reason why 
RAM is limited on the Vic is because RAM 
chips were expensive when Commodore 



designed the Vic a few years ago. The cost of 
the 4K chips used in the Vic was probably 
more than 64K chips cost today because of 
phenomenal advances in RAM technology. 

Anyway, back to memory maps. Variables 
are stored immediately following the end of 
the Basic program in memory, and they are 
immediately followed by the arrays. This 
variable storage area siores both the names and 
contents of numeric variables, but stores the 
name only of string variables along with an 
address of where the actual contents of that 
variable can be found. The contents or string 
data are stored downwards from address 7679, 
that is, top of memory. Thus free memory is 
actually the gap between string data moving 
downwards from top of memory and ihc end 
of arrays moving upwards. 

As the boundaries between these different 
areas will move as the Basic program is edited, 
or string variables arc changed, or whatever, 
the Vic must keep a careful note of where these 
boundaries arc. The addresses of these 
boundaries are stored in specific memory 
locations in standard low-byte/high-byte order. 
I know some beginners get confused by these 
terms: put simply, the Vic can only store eight 
bits of information in each memory address 
because ii is an eight -bit machine. Eight bits 
give you a total range of from to 255 only, 
but the Vic can address a total of 65,535 
addresses. Thus to get this range it is generally 
necessary to use two bytes for each address 
stored as low byte that is, least significant and 
high byte — the most significant. The actual 
address is low byte +256 (high byte). If you 
work out 255 + 256x2^5 you get 65,535 — 
thus we can address the whole Vic range using 
this format. 

The locations which we are interested in are 
as follows: 





Low 
byte 


High 

byte 


Address 


Start of Basic 

on unexpended Vic 


43 
1 


44 
16 = 


4097 


Start of variables 


4h 


46 




Start of arrays 


47 


48 




End of arrays 


49 


60 




End of strings 
moving downwards 


51 


52 




Top al memory 
on unexpended Vic 


55 



56 

30- 


7680 



Thus we know that variables arc stored in the 
area which starts at the address pointed to by 
locations 45 and 46 and finishes at ihc address 
pointed to by locations 47 and 48, 

The Vic siores all variables regardless of 
whether they are real, integer or string in a 
similar way in this area, namely two bytes for 
name, five bytes for contents — or l he address 
of where rhe contents are stored in the case of 
strings. But if only iwo bytes arc used for the 
variable name, how does the Vic s?ore the 
three significant characters thai it requires to 
define each variable? It does this by adding 
128 to ihc first or second character depending 
on rhe lype of variable- For example, the real 
— floating point — variable AA will be stored 
as 65 65 where 65 is the ASCII code for A. 
The variable AAS will be stored as 65 193 — m 
that is 65 (65+128). The variable AA% will be 
stored as 193 193. iconUnuea m w mv 



96 YOUR COMPUTER, APRIL 1983 



Sinclair ZX Specti 



16Kor48KRAM... 
full-size moving- 
key keyboard... 
colour and sound... 
high-resolution 
graphics... 

From only 

£125! 



ZX Spectrum 



nm ttAGEHTh GfiEEN C*AN 

SiEsUQCK tWffVtWO wyWOEO 






MFfM fH 



WCH « " 0VE 



REA0 RESTORE 



L PRtHl LUSI 



BRIGHT 



First, there was the wo rid -beating 
Sinclair 2X80. The first personal computer 
for under £100. 

Then r theZX8l.Withupto16KRAM 
available, and theZX Printer. Giving more 
power and more flexibility. Together, 
they've sold over 500,000 so tar. to make 
Sinclair world leaders in personal 
computing. And the 2X81 remains the 
ideal low-cost introduction to computing. 

Now there s the ZX S p ect rum (With 
up to48KofRAM. A full-size moving-key 
keyboard. Vivid colourand sound. High- 
resolution graphics. And a low price that's 
unrivalled. 

Professional power- 
personal computer price! 

The ZX Spectrum incorporates all 
the proven features of theZXSl . But its 
new l6K8ASiC ROM dramatically 
increases your computing power. 

You have access to a range of 8 
colours for foreground, background and 
border, together with a sound generator 
and high-resolution graphics 

You have the facility to support 
separate data files. 

You have a choice of storage capa- 
cities {governed by the amount of RAM). 
16K of RAM (which you can up rate later 
to 48K of RAM) or a massive 48K of RAM, 

Yet the price of the Spectrum 16K 
is an amazing £125! Even the popular 
4SK version costs only £1751 

You may decide to begin with the 
1 6K v e rsio n. Ifso.youcans ti II ret u rn it later 
for an upgrade. The cost? Around £60, 



Ready to use today, 
easy to expand tomorrow 

YourZX Spectrum comes with a mains 
adaptor and all the necessary leads to 
connect to most cassette recorders 
and TVs (colour or black and white). 

Employing Sinclair BASIC (now used 
in ov e r 500, 000 co m p ut e rs wo rldwi de) 
the ZX Spectrum comes complete with 
two manuals which together represent a 
detailed course in BASIC programming. 
Whether you're a beginner or a competent 
programmer, you'll find them both of im- 
mense help. Depending on your computer 
experience, you II quickly be moving 
into the colourful world of ZX Spectrum 
professional-level computing. 

There's no need to stop there. The 
ZX Printer -available now- is fully 
compatible with the ZX Spectrum. And 
later this year there will be Microdrives for 
massive amounts of extra on-line storage, 
plus an RS232V network interface board. 




Key features of the 
Sinclair ZX Spectrum 

• Full colour- 8 colours each for 
foreground, background and border, 
plus flashing and brightness-intensity 
control. 

% Sound - BEEP command with variable 
pitch and duration 

• Massive RAM -16K or 48K. 

• Full -ssze moving- key keyboard- all 
keys at normal typewriter pitch, with 
repeat facility on each key 

• High- re solution- 256 dots 
horizontally x 192 vertically, each 

in di v id ual ly a d dressa b le for t rue hi g h - 
resolution graphics. 

• ASCII character set -with upper- and 
lower-case characters. 

• Te letex t- co m pat ib I e - use r sof twa re 
can generate 40 characters per line 
or other settings. 

• High speed LOAD & SAVE -16K in tOQ 
seconds via cassette, with VERIFY & 
MERGE for programs and separate 
data files. 

• Sinclair 16K extended BASlC- 
incorporating unique one-touch 
keyword entry, syntax check, and 
report codes 



um 




ZX Spectrum software on 
cassettes -available now 

The Spectrum software library is 
growing every day. Subjects Include 
games, education, and business/ 
household management. Flight 
Simulation . , .Chess, . . Planetoids . , . 
History... Inventions... VU-CALC...VU-30 
... Club Record Controller... there is 
something for everyone. And the/ all 
make full use of the Spectrum's colour, 
sound, and graphics capabilities. You'll 
receive a detailed catalogue with your 
Spectrum. 

ZX Expansion Module 

This module incorporates the three 
functions of Microdrive controller, local 
area network, and RS 232 interface. 
Connect it to your Spectrum and you can 
control up to eight Micro drives. 
communicate with other computers, and 
drive a wide range of printers. 

The potential is enormous, and the 
module will be available in the early part 
of 1983 for around £30. 



inczlaii - 



Sinclair Research Ltd, Stanhope Road, 
Camberley, Surrey GU15 3PS. 
Tel:Camberley (0276) 686311. 



The ZX Printer- 
available now 

Designed exclusively for use with the 
Sinclair ZX range of computers, the 
printer offers ZX Spectrum owners the full 
ASCII character set -including lower-case 
characters and high -resolution graphics, 

A special feature is COPY which 
prints out exactly what is on the whole TV 
screen without the need for further 
instructions, Printing speed is 50 charac- 
ters per second, with 32 characters 
per line and 9 lines per vertical inch, 

The ZX Printer connects to the rear of 
your ZX Spectrum. A roll of paper {65ft 
ong and 4in wide) is supplied, along with 
full instructions. Further supplies of paper 
are available in packs of five rolls. 



The ZX Microdrive - 
coming soon 

The new Microdrives, designed 
especially for the ZX Spectrum, are set to 
change the face of personal computing 
by providing mass on-line storage. 

Each Microdrive can hold up lolOOK 
bytes using a single interchangeable 
storage medium. 

The transfer rate is 1 6K bytes per 
second, with an average access time of 
35 seconds. And you'll be able to connect 
uptoSMicrodrivestoyourSpeetrum via 
theZX Expansion Module. 

A remarkable breakthrough at a 
remarkable price. The Microdrives will be 
available in the early part of 1983 for 
around £50. 




How to order your ZX Spectrum 



BY PHONE- Access, Bare lay card or 
Trustcard holders can call 01 -200 0200 for 
personal attention 24 hours a day. every 
day. BY FREEPOST- use the no-stamp 
needed coupon below. You can pay by 
cheque, postal order, Barclaycard. 



Access or Trustcard. 

EITHER WAY- please allow up to 28 
days for delivery. And there's a 14-day 
m oney - back opt ion, of cou rse . We want 
yo u to be satisf i e d b eyo nd doubt - a nd we 
have no doubt that you will be. 



To; Sinclair Research, FREEPOST, Camberley, Surrey, GUI5 3BR. 


Order 


Qty Hem 


Code 


Item Price 
£ 

125.00 


Total 

£ 


Sinclair ZX Spectrum -16K RAM version 


100 




SinclairZX Spectrum -48K RAM version 


101 


1 75 00 




Sinclair ZX Printer 


27 


59 95 




Printer paper (pack of S rolls) 


16 


11.95 




Postage and packing: orders under £100 


28 


2,95 




orders over £100 


29 


4.95 





.7] 



Total £ 

Please tick if you require a VAT receipt □ 

*l enclose a cheque/postal order payable to Sinclair Research Ltd for £ 

*Please charge to my Access/Barclaycard/Trustcard account no. 

•Please delete/complete I I 1 1 I I I I 1 1 I I 1 I 

as applicable 

[Signature I 

PLEASE PRINT 
;Name:Mrj'Mrs/Miss | j 



1 I I I I I I I I I 1 



I Address ; 



I I I 



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I I I I 



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I 1 I 1 I I » ■ I I I I I 1 I 1 I I IYQCB03I j 

FREEPOST- no stamp needed. Prices apply to UK only, Export prices on application. 



Sinclair ZX Spectrum-technical data. 



Dimension} 
Width 233 mm 

Depth 144 mm 

Height 30 mm 

CPU/ memory 

730A microprocessor running at 3 'j MHz. 
16Kbyte ROM containing BASIC interpreter and 
operating system. 

16K-byteRAM (plus Optional 32K -byte RAM gn 
internal expansion board! or 4SK -byte RA M 

Keyboard 

40-moving-Key keyboard with lull upper and 
lower case wil h capitals Iock feature All BASIC 
words o blamed by single keys, plus 1 6 graphics 
Characters, 22 colour control codes, and 21 user- 
definable graphics character s All keys have auto 
repeat, 

Display 

Memory-mapped display of 256 pixels x 
192 pixels, plus one attributes byte per character 
square, defining one of eight foreground colours, 
one of eight background colours, normal or extra 
brig riinesr, and I lashing or steady, Screen border 
colour also sellable to one of eight colours. Will 
drive a PAL UHF colou r TV sel , or black and wh Ite 
$61 {Which Will give a scale of grey) , On channel 36 

Sound 

internal loudspeaker can be operaied over 
more than 1 octaves ( actually 130 semitones^ via 
basic &£EP command. Jack socket s at th e rear or 
computer allow connections to external amplifier/ 
speaker 

Graphic* 

Point, line, circle and arc drawing commands 
in high -resolution graphics 
1 6 pre-del i n ed graphics characters plus 21 user - 
delinab le graph ics characters, A Iso functions to 
yield character at a given position, attribute at a 
given position (colours, brightness and Hash) and 
whet her a given pi xel is set . Text may be wri lien on 
the screen on 24 lines ot 32 characters, Text and 
graphics may be Ir eelv mixed. 

Colours 

Foreground and background colours bright- 
ness and flashing arc sol by BA SIC INK. PAPE R. 
BRIGHT and PLASH commands OVER may also 
be sel. which performs an exclusive-or operation 
to overwrite any print i ng or plotting that is already 
on trie screen INVERSE wit give inverse video 
printing . These six commands may be set giobail y 
to cover all further PRINT. PLOT. DftAWorCiRCLE 
commands, or rocally withm these commands to 
cover only the resultsot that command They may 
also be set locall y to cove r text printed by an 
INPUT statement. Colour-control codes, which 
may be accessed from the keyboard, may be 
i n sen ed mto lexl or program listi ng. and when 
displayed will override the globally set colours 
unlii another control code is encountered , Bnghl - 
ness and flashing codes may be inserted into 
program or text, similarly colour -control codes in 
a program listing have no effect on its execution. 
Border colour is set by a BORDER command. The 
eight colours available are black, blue, red, 



magenta, green, cyan, yellow and while. Ail eight 
colours may be present on I he screen at once, 
with some areas flashing and others steady, and 
any area may be highlighted extra bright 

Screen 

The screen is divided mio two sections The 
top section - normally the! irst 22 lines - displays 
the program listing or the results of program or 
command execution. The bottom section - 
normally the last 2 lines - shows the command or 
program line-currently being entered, or the 
program line currently being edited. It a Iso shows 
the report messages Full editing facilitiesol 
cursor left , cu rsor n gh t i n sen a nd delete (wil h 
auto -repeat facility) are available over this lino. 
The bottom section will expand to accept a 
current lineol up to 22 lines. 

Mathematical operations and functions 

Arith mafic operations ol +. -. X, -t-.&od raise 
lo a power. Mathematical functions of sine, 
cosine , tangent and 1 heir in verses; natural log s 
a nd exponentials: sign function , absolute value 
I unci I on. and integer tunction; square root 
I u nd Ion. random num ber generator, and pi 

Numbers are stored as five bytes of Heating 
point binary - giving a range of +3 X 1Q~ 3 * to 
+7 x l0 J * accurate to S'-j decimal digits 

Brnary numbers may be entered directly with 
the BIN lunction, -.>.<.>— ,<^ and<> may be 
used to compare string or arithmetic values or 
variables to yield (false) or 1 (true}- Logical 
opei alors AN D , OR dnd NOT yi eld boolean results 
but will accept {false) and any number (true). 

User -del i nable I u nc t ions are defined using 
DEF FN, and called using FN. They may take up to 
26 numeric and 26 string arguments, and may 
yield stnng or numeric results. 

There is a full DATA mechanism, using the 
co mm finds RFAD. DMA and RESTORE. 

A real -l i me clock <s obtainable. 

String operations and functions 

String s can be corneals nated with i- , String 
variables or values may be compared with —,>,<, 
>™,< — ,<> lo give boolean results. String func- 
tions are VAL, VALS, SIRS and LEM, CHRS and 
CODE convert nu m bcrs to g h aractcrs and vice 
versa, using the ASCII code 

A very powerful siring si icing mechanism 
exists, using the formaS (xTO y), 

Variable names 

N umenc - any string starting wil h a letter 
(upper and lower case are not distinguished 
between, and spaces are ignored). 
String-A$toZ$. 
FOR -NEXT loops -A-Z. 
N umenc arrays - A -Z . 
String arrays - AS toZ$. 

S imp ie variables and arrays wit h the same 
name are allowed and dlslinguished between 

Arrays 

Arrays may be multi-dimensional, with sub- 
scripts starting at 1 . String arrays, technically 
character arrays, may have their last subscript 
omilled. yield i ng a siring 



Expression a valuator 

A lull expression eva I uator is called during 
program execution whenever an expression 
constant or variable is encountered. This allows 
the use of expressions as argument s to GOTO. 
GOSUB.etc 

It also operates on commands allowing the 
ZX Sped rum to operate as a calculator 

Cassette interface 

I h e ZX Spect rum incorporates an advanced 

cassette interface. A tone leader is recorded 
before the information to ove rcome I he automat I c 
recording level fluctualionsol some tape 
recorders, and a Sch mitt trigger is used to remove 
n oise On playback. 

AH saved information is started with a header 
containing informal i on as lo its type, l i I le . I e ngl h 
and address informal ion Program, screens, 
blocks of memory, string and character arrays 
may all be saved separol c I y. 

Programs, blocks of memory and arrays 
may be venlied alter saving to confirm successful 
saving. 

Program s and arrays may be merged from 
tape to co m bine th c m wi t h the ex isl i ng contents 
of memory Where two line numbers or variables 
names coincide, the old one is overwritten. 

Prog rams may be saved wit h a 1 1 n e number. 
where execution will start immediately on loading. 

Thecassette interlace runs at 15O0 baud, 
Th roug h two 3 .5 mm jack p I ugs 

E >; (j.-nihi ( i ii port 

This has the lull data, address and control 
busses irom theZSQA, and is used to interface to 
theZX Printer, theRS232 and NET interfaces and 
the ZX Microd rives 

IN and OUT commands give the I/O port 
equivalents ol PEEK and POKE. 

ZXftl compatibility 

ZXS1 BASIC is essentiality a subset ol 
ZX Spect m m BASIC . The differences are as 
follows 

FAST and SLOW; the ZX Spectrum operates al 
the speed of the ZX 61 in FAST mode with ihe 
steady display ol SLOW mode, and does not 
include th ese command s, 

SCROLL: the ZX Spectrum scrolls automat re - 
a I ly, asking the operator "scroll? " every I irne a 
screen i$ filled. 

UN PLOT: the ZX Spectrum can unplot a pixel 
using PLOT OVER. and thus achieves unptol. 

C haractcr set I he ZX S peclmm uses the 
ASCII character sel, as opposed to trie ZxSi 
non-standard set. 

ZX8t programs may be typed into the 
ZX Spectrum with very little change, but may 
ol course now be considerably improved The 
ZX Spectrum is fully compatible with the 
ZX Prinler. which can now print out a full upper and 
lower case character sel. and the high resolution 
graphics: using LLIST, LPRINT and COPY. 
ZXB1 software tasseiles and the ZX16KRAM 
pac k wil I not operate with I he ZX Spectrum . 





inczl 

ZX Spectrum 

Sinclair Research Ltd, Stanhope Road, Camberley, Surrey, GUIS 3PS. Tel: Camberley (0276) 635311. 




Program }. Thff vArisbi* lister 

€3800 PRINT"T =Z9«PEEK<43H256*PEEK<46) 

63001 Z9-0 i IFZ8>«PEEKC47)+256*PEEK(48>THENEND 

63082 IFPEEKC28»i27THENPRIHTCHRf(PEEK<Ze>-128>; : 29*37 i OOTO63004 

63003 PRINTCHfti<PEEK<Z8>>; 

63004 Ze*Z8+l:IFPEEK(28><:i28THENPRINTCHR*<PEEK<Z8)>; JQOTO63006 

63005 PRIHTCHRf(PEEK(Ze>-128); •IF29=0THENZ9»36 
63806 PRINTCHR$<Z9) , I Z8*Z8+6 ■ OOTO63001 



fcpntrm/etf from page $6/ 

The Vic platen variables into the variable 
storage area as and when it encounters them in 
a Basic program. In the following program, A 
would be stored first, then E, then CS. 
T0A^1:B = 1D:C$ = "C" 

Program 1 is a utility which will list all the 
variables' names used in a Bask program. It 
uses two variables itself", ZB and Z9, and takes 
up about 230 byte*. 

Line 630OO clears the screen and sets Z$ to 
the address of the start of variables 

Line 63001 sets 9 to zero. Thus if we 
subsequently 

PR1NTCHRSIZ9) 
it will print the ASCII null mentioned earlier. 
Tins also checks whether ZS is equal 10 or 
greater than rhc address of the end of 
variables. This Step is obviously redundant For 
the first pass through the program. 

Line 630Q2 checks whether the character 
stored at address VJ& is greater than 127 and if 
it is, subtracts 128 to give us a printable 
character in the range A to Z. 7,9 is then set to 
37 which means a subsequent 
PRINTCHR*(Z9J 
will give a % character — that is, we have 
detected an integer variable as the first 
character is greater than 127. 

Line 63003 prints the character if it was 
originally less than 127. 

Line 63004 increments Z8 by I so that we 
are now looking at the second character of our 
variable name and a similar process to that in 
line 63002 is performed 

Line 63005 sets Z° to 36 — the character 
code for $ — if it has not already been set to 
the % code. 

Line 63006 prints Z9 which can now be 0, 
36<S) or 37(%), and then increments Z8 by 6 to 
pick up the first character of the next variable 
name. The program then loops back to line 
63001 to continue ihe process. 

How do you use this utility? It needs to be in 
memory with the main Basic program whose 
variables you want to list. More of how to get 
it in later. You must then Run your program 
and when it ends type 

GOTO63000 
This will start the utility, ihe screen will clear 
and the variables encountered in the Basic 
program will be listed. Ignore Z8 and Z9 
which are listed at the end — they belong to 
the utility itself. Do not type Run63000 or all 
you will get is Z8 and Z9 on their own. This U 
because Run automatically docs a Clr which 
clears the variable storage area. 



If your main Basic program does not end 
but, say, continuously loops, press Run/Stop 
and Restore keys, then type 

GOTO63000 
The variables used will still be in the variabli- 
storage area, Remember, though, that they are 
placed there only as and when encountered by 
your Basic program, so try to ensure that it is 
run for long enough, or all possible 
subroutines are entered before pressing the 
Run/Stop, Restore keys or some variables may 
be left off your list. 

Now how do we get the utility into memory? 
Well, one way is to Load your main program 
from cassette and then to type in the utility 
from the listing. Ensure that you do not 
already use lines 63000 and 63006 inclusive, 
of course, or you will overwrite them. This is 
obviously tedious and prone to errors. You 
cannot Load the utility from cassette as this 
automatically clears memory first and would 
thus delete your main program. 

What is needed is the ability to merge or 
append programs — but this facility is not 
available on the Vic — or is it? 

The following procedure was devised by Jim 
Butterfield — a Commodore Vic supremo. 
The trick is to save the utility on to cassette 
not as a standard binary file but as an ASCII 
data file and then to fool the Vic inro accepting 
keyboard entry from the cassette. 

Here is the procedure — it is a little 
complicated but mighty handy in lots of cases. 
First type in the utility from the listing, Save 
in the normal wav typing 

SAVE "VARIABLES" 

This will give you a normal binary file as .i 
back up in case anything goes wrong. Now- 
type 
0PEN1J.1."VARIABLES!ASCIII":CMD1:LIST 

Press Record and Play on the tape cassette 
when asked to do so. 

When the tape stops tvpe 

PRINT* I: CLOSE1 
You now have the utility saved as an ASCII 
file. What we did here was to Open the 
cassette for a Write operation; set the Vic 
output from the screen to the cassette; and 
then listed the program not to the screen but 
direct on to the cassette. We then dosed the file 
and returned everything to normal. 

Now to merge this with your Basic program 
which is already in memory. Firstly, make 
sure that you rewind the tape to the beginning 
of the utility ASCII file. Then type 

FOKF19.1:OPEN1 
and press Return, Press Play on lape and (he 



cassette will search for the file, finally 
reporting: 

FOUND VARIABLES (ASCII! 
Clear the screen and type exactly three cursor 
downs SO that you are now on line four. Type 
?"(homer ' : POKE 198. 1 : POKE63 1 . 13: POKE 1 53, 1 
mid pre-is Return Note [hat (.home) means liti- 
Clr Home key. 

The motor will whirr into life and after a 
short time an error message will display on the 
screen, Ignore it. 

If you now List you will find the utility 
tucked on to the end of your Basic program 
and you can Run and Goto 63000 as 
previously described. 

This merging technique is also very useful 
for adding your favourite subroutines to a 
program already in memory. 

Different programming techniques are 
generally required if you are trying to save 
space or trying to speed up a program. 
Unfortunately it is sometimes difficult to do 
both ai once. If you are trying to save space, 
use single characters for variable names and 
minimise the number of variables that you 
use, Remember each new variable needs seven 

bytes in the variable storage area, and that 
siring variables also need space in the String 
data area to store their text. To speed up a 
program you need to ensure that a specific 
variable can be found quickly by the Bask 
interpreter. You remember how Basic 
al locales variables into the variable storage 
area as and when it encounters them in the 
Basic program? Every time the Basic 
interpreter encounters a variable, it jumps to 
the variable storage area and sequentially scans 
along until it finds that variable name. 
Obviously, if that variable is first in the list, it 
finds il faster than if it is the last in the list. 
Thus io speed up the process we need to 
ensure that speed-critical variables, or the 
most commonly-used variables, arc at the front 
of the list. We can do this by assigning them to 
dummy values in the first line of our Basic 
program. 

If you arc using a constant value in several 
places in a program it will speed up operation 
if you assign a variable name to it. For 
example if you arc using the constant 
32897.123 a lot, this uses up nine bytes every 
time it occurs. It also slows down the 
opera i ion as Basic has to read in all nine 
characters and convert them to a floating-point 
number for internal use. An initial assignment 
of A = 32897. 123 will not only save you 
memory but time as well. 



YOUR COMPtlT Eft APRIL 1 983 %0 1 




FOX 



ELECTRONICS 

Presents Products: 
For the Spectrum, The VIC-20, The Jupiter Ace and the ZX-81 




The Fox Spectrum Upgrade Kit (for issuu 
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5 1 rue I inns supplied. 
Unbeatable value at £24.00 

Spectrum Keyboard - A 42 key full 
ifjvcl keyboard which 2X printed circuit 
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New Sounds 
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or inexpens- 
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Or let your 
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New from FOX I lie Vixen RAM Cartridge 

lor the VIC 20. Swii citable between \GK or 
8K + 3K gives you tfi>0 Option of full T6K 
RAM or 8K and 3K HAM in one pack. 
Simply plugs into 
roar expansion port 
no re-addressing of 
existing basic, programs 
needed only £39.95 ***w. 

Let your VIC 20 talk to you with the New 
Chatterbox speech synthesizer with an 
infinite vocabulary of spoken words, 
Fully programmable and simply plugs into 
VIC or Mother boa r d Includes a series of 
software routine in Eprom to facilitate the 
programming. £57. 00 «, W 

Coming shortly from FOX 

THE TANDEM 

Expandable ex- 
pansion system, 
gives 4 expansion 
Slots for VIC 20 



cartridges. Custom 
designed case, 
plugs directly into 
computer- Further 
expanded by using 
Tandem system 
ROM socket- No 
extra power supply 
needed. £33 QQ 



THE PACER 

Uniquely expand- 
able 16K RAM 
pack for the 
Jupiter Ace- 
Similar concept to 
ZX Pandn For 
more power to 
Faster Forth you 
need a Pacer, 
1SK expandable 
RAM 179.95 
16K Module f 19.95 
bid. 




Improve your Memory 

with the ZX Panda. The 

uniquely expandable 16K RAM 

pack. Simply expanded to 

32K by insertion of a 

plug in modulo. Specially 

designed lo eliminate wobble. 

and compkrie with LEO power indication 

16K expandable RAM pack E24.5GW' ffyf 

16K. expansion module C19.95ww* flfrft 

or 32K complete for C40-Q0W W. 

or go for the Big Big pack 64K only £50,00 

ZX81 Keyboard (identical lo Spectrum 
keyboard opposite again with ZX81 PCB 
fitting inside, again without soldering. A 
great buy at only £29.95 • <2»W>. 
ZX81 Keyboard No Z 
Alternatively, go for the stylish and effic- 
ient, pushbutton, precision moulded (ASS 
as per your ZX81I 3 coloured keyboard at 
an incredibly low price of rt#v 

Unit adhejes direct lo ZX key £1 0. 00 
board. No soldering isquired. .«/ p&p 
Coming Shortly s^ now to FOX 



The Spectrum 
Echo. Volume and 
tone control. Load 
and Save without 
switching leads. 
Looks good, 
sounds good. 

£23. 50 & 



Elect! o< iif.« 141 Abbuy 
Rood, Poplay A. Basirsg 
sloko. Hunis Catalog u* 
available. Send SAE. 
AH products guaranteed 
1 yr. Oversees gust- 
omtn add a further 
E1.50P&P to all 'tcms 
Delivery 10-14 days. 



r 



Self Adhesive 
Cassette Labels 

^ ON ROLLS OR SHEETS 

Jf IDEAL FOR USE IN TYPEWRITERS 

^ A BOON TO SOFTWARE PRODUCERS 

^ CAN BE PRINTED WITH CLU B OR 
COMPANY LOGO OR SYMBOL 



CASSETTE LABELS ON SHEETS 
1 15 L abets per sheet J 



100 Libel* 
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4 Compters with lr#do* toed &)fittto\io*is 

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Minimum order GOO llbdt 

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1000 Labels. C20.00 
2000 Labels F35.00 



Al Prices include VAT and postage/ packing 

Excellent discounts for large quantities 

Pleavc send stamp tor printing price lists and sample labels 

NEW FOR 1983 - Sampler pack of different types of computer label - F20 




Unit A4 

Smeed Dean Centre 

Eu relink Ind. Estate 

Sittingbourne 

KentME10 3RN 

Sittingbourne (0795) 28425 1 24 Hrs. ) 



SPECTRUM SPECTACULAR £4.95 



DRAGON EXTRAVAGANZA £4.9S 



Two new books by Roger Valentine, Each containing 
a mammoth 50 programs (for the Sinclair Spectrum 

and Dragon 32 respectively). 

* 

From the publishers of.' 



WHAT CAN I DO WITH IK? £4.95 



WHAT CAN 1 DO WITH 16K? £4,95 



The two best program books for the Sinclair ZXSL 
A vailabie from your bookshop, or 

V&H COMPUTEER SERVICES 

182c Kingston Road, Staines, Middx. 
Tel: Staines 58041 



BUSINESS USERS PLEASE NOTE: OUR PAYROLL 
PROGRAM IS NOW AVAILABLE FOR: 31X81. SPEC-TRI'M. 
PET, BBC, KONTRON AND SOON DRAGON PLEASE 
WRITE FOR DETAILS OR SEND £2.00 FOR 
COMPREHENSIVE MANUAL (SINCLAIR VERSIONS ONLY) 



102 YOUR COMPUTER, APRIL 1003 



MADE 



Da try I Mattocks' 
new guide to 6502 
code will help you 
to write fast 
games for the 




aafcaaaaaa^^ 



Vic-20, Atom, ^c f ^: 
Oric and BBC 
Micro. 




This article is aimed at these of you who 
would normally read the words machine code, 
scream, and Turn the page quickly. If you have 
done this in the past, now is the lime 10 
change. Did you realise that Basic itself is a 
machine-code program, and thai every 
instruction such as Print, Let and Poke is 
convened into machine code, and then run as 
machine-code subroutines? This tends to make 
Basic very slow- — a machine-code program is 
in the ordeT of 100 times faster than its Basic 
equivalent. 

As in Basic, machine code is made up of a 
series of instructions which arc executed 
sequentially — one after the other — starting 
from the one in the lowest memory location 
and working up through the memory. As in 
Basic we have instructions allowing us to jump 
to a new location — Goto — execute a 
subroutine and return to the instruction 
following the subroutine call — Gosub and 
Return — add number, subtract, conditional 
jumps — If-Then-Goio — and so on. The only 
trouble with machine code is that these 
instructions are set out differently, 

A command in machine code is called a 
mnemonic and the thing, that this mnemonic 
manipulates is cailed an operand. This is 
illusi rated in figure 1, a short segment of 
machine code. 



Unfortunately, these mnemonics and 
operands cannot be typed directly into the 
computer. To speed things up, each 
mnemonic is represented by a numerical code 

— varying from to 255. These special codes 
arc called operation codes — opcodes for short 

— and it is these op-codes that the computer 
can understand and act on. 

In figure I then, A9 represents the LDA # 
command, 85 the STA command and 60 the 
RTS. Using these Op-codes and operands 
then, we can reduce any program to a series of 
numbers. 

For variables in machine code we have 
registers. A register i$ similar eg a variable in 
Basic — that is, it can be set to contain a 
particular value which can then be added to or 
subtracted from in a similar pattern to the 
variables in Basic. 

Now here is the catch. We have only five 
registers, and of those, only three are available 
to play with, If that is not bad enough, they 
can only contain integer values from 0-255 
inclusive. It may look grim, but let us assess 
exactly what we have available. 

Register 



symbol 


Nam* 


A 


Accumulator 


X 


X register 


Y 


¥ register 



SP tor Si Stack pointer 

S lor P) Status register 

The A register is the most used, and most 
important register of the five. The X register 
is used mainly as a variable or offset. The Y 
register is used mainly as a variable or offset, 
The SP and S registers are pretty tricky and 
win a separate section of their own later on; 
but basically the SP shows current position on 
stack, and S is the basis of conditioned jumps, 
eic 

Now let us try a simple machine-code 
program for adding up the two numbers 
stored in memory locations — from now on 
referred to as bytes and 1 and storing the 
result in the second byte — byre 2. The 
equivalent Basic program to do this would be 

POKE 2. PEEK (0J * PEEK 111 
In machine-code this looks like this: 

code Operand Mnemonic Comment 



IB 




CLC 


Clear the carry bit 


A5 


00 


LOAD 


Load the 

Accumulator from 
byte 


65 


01 


ADC 1 


Add contents of 
byte 1 


85 


02 


STA 2 


Store the Accumu- 
lator in byte 2 


60 




ATS 


Return to Basic 



I continued on page 10?f 



YOUR COMPUTER. APRIL 1983 103 



For the best hardware 
the best software. 



The BBC Microcomputer system is 
generally regarded to be the best micro in its 
price range you can lay your hands on. So, if 
you're thinking of buying one or already own 
one,youll want to know about the software thatls 
been specially designed for it 

Not surprisingly, it's made by Acornsoft, 
the software division of Acorn Computers Ltd., 
who designed and built the BBC Microcomputer, 
So naturally you can expect the highest quality 
software with the built-in ingenuity to fully 
exploit the BBC Micro's potential. 

Further education for everyone. 
Creative Graphics, which includes the book 
'Creative Graphics on the BBC Microcomputer 1 
(price £17.45), provides 36 programs on cassette 
producing a spectacular range of pictures and 
patterns in full colour, including animated 
pictures, recursively-defined curves and three 
dimensional shapes. 

Word Sequencing (price £11.90) contains 
three word sequencing programs on cassette. 
Each program presents a series of jumbled 
words which must be arranged on screen to form 



either a proverb, nursery rhyme title or a 
sensible sentence. 

Learn more lan guages. 
LISP (price £24.35) is the fundamental 
language of artificial intelligence research- 



y*COKNS§FT LANGUAGES I JlCORNStFT LANGUAGES 

LISP I FORTH 




MM 




cp_r-ic 



CJJG2S2 




It consists of 5.5K of machine code interpreter, 
plus 3K of initialised LISP work-space 
containing utilities and constants. It comes 
complete with a hook that introduces you to 
programming in LISP as well as some 
fascinating applications. 

FORTH (price £24.35) is a complete 
implementation of the FORTH language 
to the 1979 standard specification for the 
B BC Microcomputer Model BThis much 
acclaimed programming language is 
also accompanied by a specially 
written book explaining all you need 
to know. 

Mind-bo gglin g g ames. 
Philosopher's Quest (price 
£9-95) is an advanced adventure 
in which you tell the computer 
what you want to do and it 



rrrrrrr 





describes baek in plain English your progress 
through a fascinating world of fiendish puzzles 
to be solved. 

Snapper (price £9.95) is a colourful game 
where you guide your 'snapper through the 
maze, eating dots and fruit and avoiding the 
creatures that chase you. Complete with full 
sound effects, score and a ladder of high scores* 

Rocket Raid (price £9.95) sends you on a 
mission to raid a heavily guarded Martian fuel 
depot You must fly your rocket over mountains 
and through caverns, avoiding enemy missiles 
and dodging convoys of deadly fizzers. 

Increase your business acumen* 
Desk Diary (price £9.95) is an indispens- 
able program that can hold a file of several 
hundred names, addresses and telephone 
numbers. 

And View, a program that enables your 
machine, together with a printer, to openile ;is a 
fully operational word processor. (The program is 
in ROM, but can easily be fitted to most BBC 
Micros by your local dealer.) You can find out 




more by sending for our 

free catalogue. 

How to get 

\( •{ i r 1 1 .si. i.lj_ | Huji ranis. 

If you're a credit 
card holder and would 
like to buy cassettes of 
the programs shown in 
t hi s adverti semen t, or 
if you would like to 
know the address of 

your nearest stockist, just phone 01-200 0200. 
Alternatively, you can buy the cassettes 

directly by sending off 

the order form below to: 

Acorn soft, c/o Vector 

Marketing. Denington 

Estate,Wel li ngbo rough, 

Northants NN8 2RL, 

.Also use this form if you 

would like to receive 

ihe current free 

Acornsoft catalogue. 
Please allow 28 

days for delivery. 

l&CreditCard Holders. Ring 01-200 0200. 




R 



To: Acornsoft, c/o Vector Marketing. Denington Kstale, 
Wellingborough, IV'orthant* >JN8 2RL 



Please send me l he following:- 
pko<;ih\i trio: uv.wrm 

< i i-.itive- Graphic* £17.45 


AccmMvA 
■1U1AI. wwonlv) 

(SBX01/SBIHH} 


V'oftlSi'qwiK'inf! £11. 'tl 


IS1IKU6) 


i IM' £2135 


(SBI.O2/SBD04] 


Hiiiin $MM 


SBMH/SBIMK) 


l'bi|i..-|.|nT-U<i-1 t'l.T. 


(&BG0lj 


>IMjh|!i 1 £">.<J5 


(SHftiot) 


Koi'krlKaid t*M5 


(SBCOS) 




(SHIH>1| 



to™. 



1 enclose PO/cheque payable to Acornsoft Ltd. Or charge 

my e red it card- 

Card Number 

\rin j s/l)in<'rs/VijmMrrriiH ( !>■■! r-l-i*J 

Please send me the Acornsoft brochure, D 

Name . 



Address. 



Postcode. 



Signature. 



YO 



Ki-giMfn'd \u ir*247(>:* 



VATNih-JI.iKl-J.lHli 



>1C0RNSdrT 




ht On Your VIC 




CONVERT YOUR VIC INTO AN ARCADE 
MACHINE 

Amazing arcade action for the standard Vic 20 
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RamshaW: ALIEN BLITZ? INVADERS? GROUND 

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marked* contain machine code). You must 

have the VIC GAMES PACK cassette-only $5.95. 



RESCUE A VIC PRINCESS 

A multi-part adventure for the standard VIC 201 

All you have to do Is And the castle, defeat 

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IS THERE LIFE AFTER THE ALIEN OVERUN? 

You'li find out in Clifford Ramshaw's book 

VIC INNOVATIVE COMPUTING - undoubtedly one 

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HOP YOUR WAY THROUGH THE NIGHT! 

Ail the programs from the book VIC innovative 

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Each cassette £5.95. 



MELBOURNE HOUSE PUBLISHERS 

catalogue. 



Pitas* tend m* your ft 
Please send nw : 
looks 

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VIC 20 

VIC innovative Computing f$95 

All Melbourne Mouse cassette software is unconditionally guaranteed against malfunction 
Access or tiers can be telephoned t hrough o n ou r 24- hour ansa fo ne 1 1 1 85 § 739 7 



n Enter Tne Dragon 
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MELBOURNE HOUSE PUBLISHERS 



m 



(continued from page 103) 

There is an odd quirk in 6502 when adding 
up; the only Add command we have is ADC — 
add with carry. This cakes The contents of the 
carry flag and adds I hem TO the result of the 
original calculation we were hoping to make, 
If the carry flag were set then — say it was set 
to 1 — the result obtained when The ADC is 
performed would be I too high, So the CLC 
command sets carry ecjua' to rero and ..c 
should gei the right result. 

So now we have our mac" i.j» ~. iram 

in the form of opcodes sod or . is. vhere 
can we put this little mast*- -■ oe? On the 
Vic- 20, it is best place*! under l he 

screen memory, as her' .ill not interfere 
with Basic ait all. 

A program to Poke our machine-code 
program into memory is given in figure 2. 

Type it in and Save it. Check lines 50, 60 
and 100 especially as any mistake here could 
Cause a crash. When "Finished" appears our 
program has been loaded into bytes 6700 
6707, To run this program we use the Sys 
command. To run the machine code starting 
at 6700, tvpe in 

SYS ©TOO 
and hit Return. You should get an almost 
instantaneous reply of "Ready" and the cursor 
blinking. The machine has run the progranij 
but it was so fast that you did not notice. To 
check that it has done something trv — 
PRINT PEEK (001 + PEEK 11 1, PEEK (21 

As location 2 = location + location 1, the 

two printed numbers should be the same. 

The stack is an area of memory situated 
around 600-650 reserved for remembering 
data in a first in last out — FII.O — manner. It 
is called a stack because of its similarities with 
a stack of other things, for example, plates. If 
you have a stack of plates and then add a plate 
to the top of this stackj then the next plate you 
take from that stack must be the one you have 
iust added. The same is true f<»r mir memory 
stack. The last item to be pushed into the top 
of the stack will be first to be pulled off it. 

It is by using the stack that Basic returns 
from a subroutine to the right place, knows 
when it has finished a For -Nest loops and so 
On, The pointer which tells the 6502 what 
position it is at in the stack is the stack pointer 
register SP. As return addresses are added to 
the stack each time a subroutine call is made, it 
is best to avoid using the stack as much as 
possible. Unless you keep a strict record of 
what exactly you arc doingj what you put in 
might not be what you get out at some later 
date. 

The status register — SR — is better 
considered as a group of eight bits rather than 
just one byte. It contains seven flags and one 
unused bit. They appear as — 
Bit number 7 6 5 4 3 2 10 

Symbol N V -GDI Z l 

Bit 7 is the sign bit. It is set whenever a 
result from Add instruction is a negative 
number in two's complement format. 
Translating this, it means that N bit will be 
the same as Bit 7 in the accumulator after 
many operations. 

Bit 6 is the overflow flag used in two's 
complement subtraction when the result could 
be wrong due to a carry from Bit 6 to Bit 7. Bit 
5 is unused. 



Op -code 


Operand 


Mnemonic 


Operand 


Basic equivalent 


A9 


03 


LDA# 


03 


A = 03 


85 


06 


STA 


05 


Poke 5, A 


60 




RTS 




Return 


Figura *. 











Bit 4 is the Break flag and is set afier the Brk 
instruction to let us know that it is a software, 
not hardware, break. Bit 3 is the Decimal flag 
and informs the processor whether to use 
BDC or binary representations of data. Bit 2 is 
the interrupt flag, when set, it will prevent any 
interrupts. 

Bit 1 is my personal favourite. This is the 
zero flag and is used to indicate that the result 
of any particular operation equals zero. 

Bit is the carry flag which is used for a 
carry during additions. It can often be thought 
of as an eighth bit during additions. These 
flags form the basis of all the Conditional 
Jumps in 6502 assembly. 

We get the following branches; 



Status register 
C = 
C = 1 
Z = 1 
N = 1 
Z = 

v=o 

V^l 



Branch 
BCC — if carry clear 
BCS — if carry set 
BEG - if equal to 
BMI — if minus (negative) 
BNE - if not equal to 
BPL — if plus (positive) 
BVC — if overflow ctear 
BVS - if overflow SSI 

These branches correspond to the If-Then- 
Goto sequence, except that one does not 
specify a branch and an address but a branch 
and a displacement between 127 and -126- 
This displacement is added to the program 
counter — PC, or two-byte register which 
contains the address of the instruction 
currently being executed — to send it either 
forward or backward by that displacement. 

To illustrate this, here are two programs; 
the firsi clears the screen, the second JStps up 
and down the music scales. The asterisks on 
the programs indicate a memory byte to be 
skipped in the branch instruction. 
Assembly code Mnemonics 
A2 00 LDX # 

A9 20 LDA $20 

9D*00-1E- STA$1E00,X 

90*00* IF* STA$1F00,X 

CA* rn x 



10 POKE 56, 26: POKE 52, 26: REM 

RESERVE SPACE FOR THE 

PROGRAM 
20 COUNT = 0: REM POINTER TO 

DATA 
30 READ 0$ : (F DS - THEN PRINT 

"FINISHED" '; END 
40 D1$ - LEFT * {DS,1j : 02$ - RIGHT 

$ (D$,1> : REM CONVERT 

HEXADECIMAL 
SO V m (ASC (Oil) - 48 + (IASC I01SJ 

>64) -71) M6 : 
60 V - V h (ASC <D2$) - 48 * |{ASC 

|D2S1>64) * ?)> : REM DECIMAL 
70 POKE 6700 + COUNT, V : REM 

STORE THE MACHINE CODE !N $700 

ONWARDS 
80 PRINT 16700 + COUNT) ; V : COUNT 

= COUNT f 1 i GOTO 30 : REM 

REPEAT FOR NEXT BYTE 
99 REM : HERE IS THE DATA OF THE 

PROGRAM 
100 DATA 18, AS, 00. 65. 01, 85, 02, 60: 
110 DATA * i REM END OF DATA. 

Figure 2. 



DO* F8* BNE $F8 

60 RTS 

The Basic equivalent of this program would 
look like this: 
10 X - 256 
20 A = 32 
30 Poke 7680 + X, A 
40 Poke 7936 + X, A 
50 X = X-1 
60 lFXOGThen30 
70 END 

The FS in the branch instruction is the 
displacement mentioned and is obtained thus: 
count how many bytes are needed to skip 
backward, in this case 89. Then this is 
converted to eight-bit binary. One's 
complement is then calculated in binary and 1 
is added to obtain two's complement. The 
resultant sum looks like this: 

- 89 

= OQ001001 

- 11110110 
= 11110110 

1 + 



= 11110111 
The eight-bit binary is then converted to 
two-bit hex: F7 is the result. If a line 5 is 
added to the Basic program 
5 FOR 1-0 TO 512 : POKE 7680 + 1,160 : NEXT 
and the rest entered and Run, this will show 
you what the machine-code program does. To 
enter the machine code, change line 100 in 
figure 2 to: 

100 Data A2,00,A9,2Q,9D,OQ,1E,9D,Oa,lF,CA, 
DO, F8, 60 

Do not forget to Save, then Run* iust in 
case. To run the machine code try Sys 6700. 
The program should respond with a blank 
screen and a **Ready" plus cursor. 
Here is the second program. 
Op-code Operand Mnemonic 
A9 OF LDA # OF 

80 0€ 90 STA 90DE 

A2 FF LDX#FF 

AO 00 LDY # 00 

CA' DEX 

SE* OA* 30" STX 900 A 

8C- OB* 90* STY 900B 

C3' INY 

FO* F6 BEG F6 

60 RTS 

The Basic equivalent looks like this: 
10 A- 15 
20 POKE36878,A 
30 X -255 
40 Y = 
50 X-X-1 
60 POKE 36874, X 
70 POKE 36875,X 
80 V - Y ► 1 

90 IF Y = Q OR Y = 256 THEN SO 
100 END 

The F6 in the branch-if-equal-io-0 command 
is obtained by the same process as was used to 
obtain F7 previously. 

To enter this program change line 100 to 
100 Data A9,DF,8D,0E,90,A2,FF,AO P O0,CA 
1 02 Da ta 8£ . A, 90. 8C,0B ,90, C8, FO. F6, 60 

When the program has been Saved, try Sys 
S7Q0. This will Run the program, but it may 
be a bit fast, so until next time, can you think 
of a machine-code routine to slow it down? I 



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The. provision of colour, sound and uscr- 
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full and excitingly implemented on Spectrums- 
The usual method of producing the illusion 
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at one position, and then erasing it and 
printing one character position further along 
ihe screen. This method is certainly fast 



First d$t& byte for each tine. 



Second byte. 

1_ 











































' 





























































































































































































Figure 1. 



Figure 2. 


■ ■ 


I I 



enough when used in Basic programs on the 
Spectrum if only one or two graphics 
characters require animation, but the move- 
ment has a jerky appearance, because the 
smallest distance that a character can be 
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Most commercially-written software uses 
machine code in order to achieve the required 
speed and smoothness of movemem, but 
writing an entire game in machine code is not 
a task that most home programmers would 
relish. It is therefore necessary to consider 
other methods for speeding up the action in 
Basic programs. 

Smooth routine 

On the ZX-81 it is possible to short»cut the 
Print statement by Poking characters directly 
into the display file, thereby getting slightly 
faster graphics. Unfortunately the Spectrum's 
display file is laid out in a very complicated 
fashion — see page 164 of the manual — and it 
is not really feasible to do the same thing on 
this computer. 

For this reason 1 have written a machine- 
code routine especially for the purpose of 
enabling games programmers to obtain faster, 
smoother animation from Basic, ]t is intended 
to be used with user-defined graphics 
characters, which can be made as large as 

{continued on next page} 



YOUR COMPUTER. APflNL 1 933 1 1 1 



(./sting 5. 



h 






* Ren 

■.' LLEH» E-SlSV 
» a PHPCR ft BORDER 7. CL3 

*?# Fpit ^.see to 100 step -sb 

3J ED 5ut lOW 
4fl fit,"! U 

50 ink a 

E0 STOF 

70 REM * * | »I*MI* t »*•■! » t ♦-♦» «■ » ■ 

i#C> POKE 6SloiJ,l+: Punt &E>i«4il 
a IB FOR S-O TD IBB STEP 3 SO •. 

JB SBI): NEXT K 
13V FOR x-AUB TO STEP -&. Go 

SUB £00. NEXT X 

130 POKE bbl*B,tt t'OHE bElBl.U 
1*0 POKE BBUSj^e: POKE fcJVl&S, 

190 POKE tSlt,«.e 

1&« HrtNPOHUC USP 6S171 

170 RETURN 

itjfc fitl-l IMHtllltMltMMllttt 

206 POKE 6Sltl,v POKE BS1D3.11 

?ia POKE bSlbM.i 

2SB GO 3 UP 300 

83B POKE OSlM^-9; POKE C-Slbj, 

a 

B+B POKE frSl«,4 

sac uo sue 3H4 
a«a ncTUHK 

S7B REJ1 •»<«41IIMIf»>lflllll(l 

300 rOfl t»» TO «.; PRINT INK c; 

310 PORh «l»»,C*0*tV 

33B RRMOOKXZE USA 65171 

330 NCXI C 

34-0 RETURN 

31jB HEM *»tt*ltI*t»l»VUt^itti 



(continued from previous page) 
desired and primed by a single call to the 
routine. In addition, the graphics can he 
located at any position on the 256 x 176 high- 
resolution screen, and can therefore be made 
to move by as little as one point at a time. This 



Listing 1. Machine-Code dump 


















2 


175 


8 


!.; 


1 


1 


40 


9 


7 


221 


53 


10 





O 








O 


221 


221 


33 


7 


32 


217 


203 


42 


178 


92 


221 


35 


42 


33 


203 


16 


23 


221 




123 


92 


221 


94 


5 


29 


10 


22 1 


53 


6 


32 


19 


20 - 


53 


203 


35 


203 


35 


221 


53 


10 


40 


6 


7 


22 


O 


25 


235 


221 


78 


221 


53 


io 


32 


250 


1 19 


O 


221 


70 


1 


221 


126 


193 


241 


5 


61 


32 


155 


3 


243 


197 • 


221 


126 


2 


201 


221 


53 


9 


32 


10 


221 


119 


6 


205 


170 


34 


221 


203 


4 


70 


40 


4 


221 


119 


7 


221 


52 


7 


235 


35 


78 


235 


221 


53 


47 


230 


7 


60 


221 


119 


8 


32 


204 


221 


S3 


10 


S 


213 


229 


205 


219 


1 1 


40 


b 


7 


221 


53 


IO 


225 


209 


221 


2D3 


4 


70 


32 


250 


119 


33 


213 


229 


32 


5 


1 








24 


245 


205 


219 


11 


241 


225 


5 


233 


70 


35 


78 


235 


209 


221 


54 


8 


8 


221 


221 


54 


9 


S 


221 


54 


54 


7 


1 


24 


153 




10 


9 


1 26 


221 


53 


7 















is a considerable improvement over the coarse 
32 x 22 resolution normally obtainable The 
colour of the graphics can be controlled from 
Basic with the normal Ink, Paper, Bright and 
Flash statements. 

The machine code occupies 197 bytes, and 
the safest way to store it is to move RAMiop 
downwards in memory, using the Clear 
command, and place the code 1 between the 
Basic area and the user-defined graphics. 

The address of the routine will therefore be 



different for 48K and 16K Spectrum*, The 
routine itself, however, is the same for both 
computers, and a dump of the machine code is 
given in listing 1. Owners of 48K machines 
can use the loader program in listing 2. Enter 
this program and Run it, inputting the 
numbers from listing 1 as prompted: read the 
numbers from left to right. 1 would advise you 
to check the machine code before Saving it or 
attempting to use it. This can be done with the 
(continued on page IIS) 



Listing 3. Disassembled machine-code, 
















ORG 


65160 




INC 


A 


L6 


LD 


(HL) ,A 


XROS 


DEFB 


2 




LD 


(IX+8) ,A 




POP 


BC 


YPDS 


DEFFJ 


175 




PUSH 


DE 




POP 


AF 


WIDTH 


DEFB 


8 




PUSH 


HL 




DEC 


B 


HT 


DEFB 


8 




CALL 


OBDBH 




DEC 


A 


MODE 


DEFB 


1 




POP 


HL 




JR 


NZ,LINE 


UDGCH 


DEFB 


1 




POP 


DE 




REf 






DEFB 







BIT 


0, (IX+4) 


L7 


DEC 


< IX+9) 




DEFB 







JR 


NZ ? 5 




JR 


NZ,L4 




DEFB 







LD 


BC,0 




BIT 


0, (IX+4) 




DEFB 







JR 


LN1 




JR 


Z, L4 




DEFB 







EX 


HL,DE 




EX 


HL,DE 


I 








LD 


B, (HL> 




INC 


HL 


START 


LD 


IX, (23730) 




INC 


HL 




'_D 


C, (HL) 




INC 


IX 




LD 


C, (HL) 




IX 


HL,DE 




LD 


HL T (23675) 




EX 


HL,DE 


L4 


'EC 


(IX+8) 




LD 


E, CIX+S) 


LN1 


LD 


<IX+9),8 




R 


N2,L3 




DEC 


E 


LI 


LD 


(IX+IO) ,? 




EC 


(IX+10) 




SLA 


E 




LD 


A, (HL) 




IR 


Z,LB 




SLA 


E 




DEC 


CIX+7) 


L9 


RLCA 






SLA 


E 




JR 


Z,L3 




DEC 


(IX+iO) 




LD 


D, 


L2 


RLCA 






JR 


NZ,L9 




ADD 


HL„DE 




DEC 


(IX+IO) 




,j h 


NZ,L3 




EX 


HL, DE 




DEC 


(IX+7> 


LB 


LD 


(HL) ,A 




LD 


C, UX+0) 




JR 


NZ,L2 




INC 


HL 




LD 


B, <IX+1> 


L3 


SLA 


C 




PUSH 


DE 




LD 


A, (IX+3) 




RL 


B 




PUSH 


HL 


LINE 


PUSH 


AF 




RLA 






PUSH 


AF 




PUSH 


BC 




DEC 


(IX+IO) 




CALL 


OBDBH 




LD 


A, CIX+2) 




DEC 


(IX+6) 




POP 


AF 




LD 


UX+6) ,A 




JR 


NZ,L7 




POP 


HL 




CALL 


22AAH 




DEC 


CIX+10) 




PGP 


DE 




LD 


CIX+7) ,A 




JR 


Z,L6 




LD 


(IX+8) ,8 




INC 


CJX+7) 


L5 


RLCA 






LD 


(IX + 7) , 1 




CPL 






DEC 


CIX+10) 




JR 


LI 




AND 


7 




JR 


NZ,L5 


■ 

9 


END 





1 13 YOUR COMPUTER. APRIL 1983 






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1 14 YOUR COMPUTER, APRIL 13S3 






(continued from page tt2i 
same loader program by deleting lines 20, 30, 
70 and 90, and changing line 30 to: 
80 PR [NT TAB 10; PEEK i 
If all is correct, you should Save the routine 
with the command: 

SAVE "animate" CODE 65160J97 
Owners of 16K computers need to make the 
following changes. In listing 2, change line 20 
to 

CLEAFt 32389 
and line 50 to 

FOR i-32390 TO 32586 
Save the routine with the command 

SAVE 'animate" CODE 32390,197 
You can now test the routine by clearing the 
screen and issuing the command:— 

R A N DOMIZE US R 651 7 1 48K 
RANDOMIZE USft 32401 16K 

Whereupon the character in user-defined 
graphic "a" — usually a capital letter A — 
should appear at the top left-hand corner of 
the screen, If [his docs not happen you have 
made a mistake while entering the machine 
code. 

If the computer has crashed you must 
remember to reset RAMtop by giving the 
appropriate Clear command before reloading 
your copy of the routine and checking it. 

If all went as expected, here is how to use 
the routine from a Basic program. If you 
examine the disassembled routine in listing 3, 
you will see that the first fj bytes are used as 
variables, XPOS, YPOS and' so on. These 
names will not be recognised if you iry to use 
them in a Basic program, but by Poking 
different values into these six bytes you can 
control the operation of the routine as follows. 

Routine control 

XPOS - address 32390 for 16K, 65160 Tor 
48K. — is the X co-ordinate of the Lop left-hand 
corner when the graphic character is printed 
on the screen. Possible values are the same as 
are allowed for the PLOT command, that is 
to 255* 

YPOS - address 32391 or 65161 - is the Y 
coordinate of the top left-hand corner of the 
graphic character when printed on the screen. 
It may take values from — bottom of screen 
— to 175 — top of screen. 

Width - address 32392 or 65162 - this is 
the number of points left-right in the character 
to be printed. 

HT - address 32393 or 65163 - is the 
number of points top-bottom in the character 
to be printed. 

Mode — address 32394 or 65164 — has the 
value I if you wish to print a character at the 
current position, or if you wish to erase a 
block of Width x HT points at the current 
position. 

UDGCH - address 32395 or 65165 - this 
must have a value from 1 to 21, arid ii tells the 
routine where to find the data for the character 
that you want to print. A value of I means that 
the first byte of data is held at address USR 
"a", that is, the first byte of the user graphic 
"a", while a value of 21 means that it is held in 
address USR "u". 

Values Poked into these sik bytes before 
calling the routine will be unchanged on exit, 
SO, if priming more than One character, you 
may not need to update every byte. You will 
get strange results, or possibly cause a crash if 



you attempr to set XPOS and YPOS to values 
which do not permit the character you wish to 
print to fit onto the screen, and so your Basic 
program may need to include a check to 
prevent this. 

Different colours 

The routine prints the graphic character in 
the colour defined by the current contents of 
system variable ATTR T - location 23695, If 
you want to print characters in different 
colours, you can set ATTR T from Basic 
without changing the current print position by 
using a dummy Print statement such as 

PRINT PAPER 6: INK 1; 
before calling the routine. The Flash and 
Bright statements can also be used. 

If you use the routine to print user-graphics 
consisting of eight-by-eight points, then the 
method of storing the pattern is exactly the 
same as described in chapter 14 of the user 
manual. However, the routine can handle 
graphics of any size, and the method for larger 
characters is slightly different. 

Firstly, design your character on a piece of 
squared paper. I am going 10 use the routine to 
move the character across the screen by two 
points at a time, and so it is best to leave a 
margin at left and right edges of two blank 
columns. The operation of moving left or 
right by two points and printing at the new 
position will then automatically print over the 
old space invader, saving the trouble of erasing 
it first. The character we want to use therefore 
consists of 14 by 11 points. 

If the width is. not an exact multiple of eight, 
you must add the required number of blank 
columns to the right-hand edge. The width of 
the character is then divided into eight-bit 
sections, which can be described by a Bin 
number as usual and stored in the user-defined 
graphics area. A program like that in listing 4 
can be used for this. The first byte of data for 
the character is going to be stored in address 
given by Usr "a". When entering data for 
your own characters, remember that the data 
for the top line is stored first, then she second 
line and so On. 

Since the space invader occupies 22 bytes, 
that is, all of graphics "a" and "b", plus most 
of "c", the next unused section begins at USR 
"d*\ This is where the four bytes of data 
needed for the character in figure 2 can be 
Stored. When these two lines are printed over 
the bottom two lines of the space invader, its 
legs will appear io move while it moves across 
the screen. Enter and Run listing 4. You can 
save the user-graphics if you wish with 
SAVE "chars'CODE USR "a ".32 
Erase listing 4 — you can do this with New 



Listing 2. 








io 


REM listing 


2 fiaio 




2C 


CLEAR 


■. '.!'■- 






SO 


CLS : 


PRINT 


'ont-ar numbwrn from 


listing 


t m ■ 






40 


PR I NT 


t PRINT "addrftptt 


content*™ 


30 


FOR i- /.!•■, 1 isi'i 


TO 65336 




60 


PRINT 


ii 






70 


INPUT 


n 






BO 


PRINT 


TAB IO 


in 




*0 


POKE i.O 






1O0 NEXT 


i 






I6K uftri chang 


d 1 i nun 20 


& 50 


tOJ- 








20 


CLEAR 


S23B9 






SO 


FOR i 


■32J90 


TO 323SA 





Listing 4. 



IV RErt character in -fiqiire 1 

20 FOH 1-LI5P "<«- TG USK *ik**4l 

30 READ hi POKE a ,n 

•DM ■: I I 

50 DATA L»1N OOOOOl J 1 , BIN lOOOGOOCI, 

tun oocmm.stN j n'j<-"'X>u.niH win m. 

BIN I M lOQOO. Blft Oi'l ii'">l ! .BFW OOllDOQO 
60 DATA DIM 'X> 1 1 OO 1 1 , H I N CKjiiOQOO, 

BIN uOUIl ll.UIrt 111 IiXilXl.BiN 00011111, 

mti 1 1 iOOOOt*, VIH 0oClttJOO,81N IOIO00OO 
70 D*rp bin poniOOll .hIM OOlPOWO, 

BIN OOIOOOOO.BIN OOOl iK>0C, BIN OOlOOOtJQ 

P1M OOOlOOMS 
90 hfcrt cK.r*ct»r lo Mgtirs 2 
?0 FOR 1-USP "d" TO USPI -0"+3 
lOO READ nt PO! E i,fi 
110 Nt-:*T i 

120 DATft BID 0QO01OOO,BIN 01OO9O0O, 
SIN OOOOlOOO, BIN MOOOO<>* 



since the routine and the uterographies are safe 
above RAMtop — and enter the program in 
listing 5, This will make a row of seven 
multicoloured space invaders walk across and 
down the screen in the manner so farnilar to all 
devotees of the arcade game. Note that all 
seven invaders can be erased with one call to 
the routine when moving down a line by 
setting Mode to 0, Width to 140 and HT to 
II - lines 130- 160. 

Other sections of the program are as follows: 
lines 300-340 print the row of seven characters 
in the seven different Ink colours. Lines 
200-260 call the subroutine at line 30Q to print 
first the row of space invaders at a certain 
position and then overprints their legs with 
the character in figure 2, 

Lines 100-170 make the invaders move first 
left to right across the screen, and then walk 
back in the reverse direction, Lines 20-60 
make the invaders move down ihc screen after 
walking across it. 

Fast graphics 

From this example, you should be able to 
see bow the routine can be used to advantage 
in your own programs, producing spectacular, 
fast-action graphics. 

Finally, should you find that the user- 
defined graphics area is not large enough to 
store the number or size of characters that you 
wish to print with this routine, you can 
relocate the routine and use a larger area of 
RAM for character 51 or age. 

This can be done very easily since the 
machine-code routine can be put anywhere, 
provided that its first byte, that is, XPOS, 
comes immediately after RAMtop. For 
example, if you wanted to use the routine to 
generate 40 characters per line printing,, you 
would need to define your own si x-by -eight 
character set, or copy the Sinclair one, missing 
out the left and right hand margins which give 
spaces between the letters. This would require 
a large area of memory — about 800 bytes — 
for storage, and so 48K owners would need to 
relocate the routine at, say, address 64000 by 
issuing a command 

CLEAR 62999 
and then loading with 

LOAD "animate" CODE 64000 

The user-defined graphics area can now be 
moved to start at address 64300 by Poking 
system variable UDG — location 23675/6 — 
accordingly. This gives ample space for an 
alternative character set or for any other user- 
graphics. 



¥0U R COMPUT ER. APRl L 1 98 3 115 



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116 YOUR COMPUTER, APRIL 1983 



p 

r. 



THIS PROGRAM produces 3 variety of Sounds 
at the same time as executing instructions of a 
program completely separate from it. It is self- 
contained, so that a program written with it 
can run on any 4SK. Spectrum. 

To do this I used the Z-80 interrupt mode 2. 
First of allj prepare a tape ready to record ihe 

rogram on, and then type in the listing in 
figure 1. This is the editor which creates nhe 
sounds used in a program, There is an extra 
line to be inserted in the program missing 
from the listing printed. It is: 
755 SAVE "Sp&csound" CODE 65002,271 . 

PAUSE 50 

It is important that you check your typing 
against the listing again when you have 
finished, to make sure there are no Poke 
errors, which could crash the program. Do not 
run the program at this stage, as it contains 
calls to a machine-code routine you have not 
yet put in. When you are satisfied with your 
typing save a copy of the program by typing in 

SAVE "Specsound 2" LINE 1 
and Verify it, Leave the tape in position after 
Verifying. 

Now clear the machine by typing 
PRINT USR 
and input the listing in figure 2, Again when 
you have finished, check each number against 
the listing. 

Now Run the program, The location and 
contents of the addresses Poked into will be 
scrolled up the screen, When H is finished, 
before Saving it, Jook at location 6527) on the 
left and check that it holds the number 251. If 
there is anything other than that there, you 
have probably put an extra number in the 
Data statements, or left one out. Go back and 
check it again. 

Now press a key to save this code straight 



From laser explosions to 

ducks quacking, Ronald 

Seniscal's complex sound 

generator provides the 

special effects — without 

interrupting your games 

program and without 

special circuitry. 

after the Basic editor, You have now finished 
the entire program. After doing that, use as a 
command 

PAUSE 50: PRINT USR 66002 
One second later, the number nine should 
appear and there will be a slight clicking noise 
If anything else happens, lherc is an error. 

Clear the machine again — after verifying 
the code — and load the entire program in 
from the beginning. The second part will be 
automatically loaded after the first, and then it 
will auto-run. 

You will see nine numbers, with their 
names, and a cursor. The cursor is moved by 
the up and down cursor keys. While the cursor 
is pointing to a number, thai number can be 
changed. This is done by pressing the left 
cursor to decrement, and the right Cursor to 
increment. To change more quickly use the 4 
key to decrease by 1 and 9 to increase by 1 0- 
You cannot go beyond the values 0-2 55> and 
the program protects against this. 

These numbers actually form a part of the 
machine code and it is by changing these that 
you change the sound. To hear a sound at any 
time, press P, You can do this while another 
sound is still being put out without danger of 
crashing. 



Now the names to which the numbers are 
related. First is the starling point, if you think 
of a complete sound as having a value of 255, 
changing it to 127 would mean that you would 
hear it from halfway through compared to the 
first version. 

Second is speed. is the fastest here, and 
higher values mean the same sound is 
produced, but more drawn out. 

The next four values act against each other 
inside the routine. The first two control the 
length and frequency of the click being 
produced, and the second the gap between the 
clicks. To find out more about these, 
experiment with them, but the second number 
of each pair is usually set to 255. To avoid 
doing this manually, press T. 

The next two should be set cither to 1 or 
as anything over I will be taken to mean 1 . 
The first one, if set to 0, causes the pitch to 
rise. Setting this to 1 does the opposite. The 
Second variable does the same for the silences 
between the clicks. 

The last variable determines the actual 
quality of the sound, as balanced against the 
speed penalty. A program requiring high- 
quality sound will run more slowly than one 
which is not as critical. Setting 1 is awful, and 
should not be used; 6 is highest and sounds 
like a custom-built generator but runs ai only 
10 percent of normal speed so should only be 
used in machine-code programs. A useful 
compromise is 2. Anything over o is for 
special effects . Try it and see. 

Technically this number is used as the high 
byte of a number which is decreased by one 
when a sound or gap is put out, returning 
when xcro, so six times 256 + 255 or 1,791 
clicks can be put out every interrupt. This is 
(continued on page 7 J9) 



COMPLEX SOUNDS 



Figure t. The sound editor. 


, 346 , , 230 , 2S5 




170 DRTR 2S3 , 203, 71,70,40, X ,47, 




71 , 50 , 72 




130 DRTR 92, 203, 63,203,63,203, 6 


1 REM data for interrupt sou 


3 237 121 .45 
i90 DRTR "204, 132,254, 16,243,21, 


nd driver 


10 CLEftR 64968 


32, 191,29,32 


25 POKE £3692,255 


200 DRTR 186 , 235 , 34 * 165 , 254 , 225 


30 FOR 4^65002 TO 6^373 


, 209 , 193 ,241, 237 


40 RERD X : POKE a,Z: FRIKT a,P 


210 DRTR 86,251,201,0,0,37.192, 


EEK a : NEXT a 


226, 34 , 165 


4-5 5RUE "Specsound"CODE 65003, 


220 DRTR 254,50,168,254,130,50, 


271 


167,254, 122,50 


60 DflTB 50 , 162 , 254., 60 , 33 , 24-7 , 9 


230 DRTR 169,254,123,50,47,254-, 


0,i.9 


226, 209 , 193 , 24 1 


70 DRTR 0,9, 61,32, 252> 19^, 174 , 


240 PflfTB 25 1 , 237 ,77,0,0,, 0,0,0,0 


254,0,0 


^0 


60 ORTH 0,9,3,254,0,0,245,197, 


250 DRTR 10,31,1,0,0,0,0,243.23 


213 * 223 


3,54 


00 OftTR 2«m,191,2,42,l6S,254,l 


260 DRTR 71,0.126.60.50.47,254, 


24,161,40,2* 


35, 125,60 


100 DRTR 229.33,255,2,58,167,25 


270 DRTR 50,49, 254 , 35 , 126 , 5© , 52 


4-, 71, 58, 159 


. 254 , 35 , 126 


110 DRTP 254,67,56,4-7,254,96,56 


=200 DRTR 50*54,254,35,126.50,84 


, 168,254, 14 


,25=4,35,126 


120 DRTR 254, 201, ©,0,33,2655, 2,1 


290 DRTR 50 , S& , 254 , 35 , 126 . 163 >* 


4,254,3© 


0,4, 253 , 203 


1313 ORTR 14 , 22, 1 , 183 , 946 , 0, 230.. 


300 DRXR 71,190,35,126,163,40,4 


2S5 .263,203 

140 DRTR 71,70,40 . 1,47 ,71, S3 .72 


,253,203,71 


310 DRTR 205,35,126,183,32,2,62 


, 9fi , 203 
1h,K» DRTR &3,2d3,63,203,63,24&,2 


, 5 , 50 , 20 


320 DRTR 254,50,43,254,62,253,2 


4,237, 121,45 


37,71, 237,94 
330 DRTR 251,201,0 


160 DRTR 204 ., 132 , 254 , IS , £43 .. 123 



YOUR COMPUTER, APRIL 1 9S3 1 1 7 



AMSOFT 



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FOR DISCERNING 

ZX81 AND 
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AM-ZXEDIT for ZXS1 and Spectrum £4.00. 
AMAZON for ZX81 £8.00, available for 
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1 18 YOUR COMPUTER, APHIl I9S3 



{continued from page 117} 
why everything slows down so much when 
using [his number in the length of interrupt 
variable- is not really useful so the routine 
sets it to 5. 

Of course, one sound is not much good on 
its own, so room has been made for 2S of 
them. The red number in the top left of the 
screen is the field number — to 27 — and is 
changed by pressing C and then the number of 
the field you want to work on. A Held is 
unchanged when you are not actually working 
on it, so you can go back to ii ai any lime. 
Pressing M moves one field to another. Give 
the si a rifle id and the destination; the field will 
be copied and the one put on the screen for 
you to work on will be the new copy. 

To make more copies of this program use 
Goto 1000. Both parts of the routine will be 
automatically Saved. Dot not use any Print 



commands, as the numbers are stored in the 
printer buffer. 

It is recommended that you play around 
with this routine for a while before actually 
incorporating any sounds into a program of 
your own. When you are ready to do this, use 
the following as guidelines. 

Calculate how many sounds you want in a 
program, and write down the number — 
Starting at — and a description of the sound, 
that is, what it is meant to represent. Write 
your game with this in mind. 

Inside your program, when you want a 
sound to be produced at a particular point, just 
Poke the field number into 65 1 8& and then use 
theinstruetion LCTsd-USR 65002 

While writing these put a Rem in front of 
them so that if you accidentally Run it, it will 
not try and execute these instructions. 
Remember to remove them when the machine- 



code routine is in place. At the start of your 
program put these commands 

CLEAR 64900; LOAD "Specsound" CODE: 
LOAD "" CODE 
and then Save the program, keeping the tape 
positioned after the item you have just saved. 

Load the editor and create the sounds you 
want as shown above. When you have 
finished, press S and then the first field 
number you want Saving, then the last and 
finally the name. The machine-code routine 
will then be copied on ro tape, followed by the 
sounds, and that is all there is to it. 

It is possible to Save and Load before a 
sound has finished. The sound will stop for 
the duration of these commands, but resume 
where it left off afterwards. List and Edit can 
all be performed during sound production. To 
stop a sound, select a field which is blank and 
make it produce thai sound 



Figure 2. 






260 IF INKEY» = '-p" OR INKEY *-"P" 
THEN LET I =USR 65002 


1 REM TJ-*iS pro* is 


290 IF INKEY$="C" OR TNKEY*-"C" 


© R sen 


is ca I 1^62 


THEN GO TO 600 


2 RESTORE : 


CL ERR 6*9B0 


295 IF INKEYS-"S" OR XNKEY*-"S" 


3 BORDER 0: 


PRPER 0; INK 7: C 


THEN GO TO 700 


1_5 






300 LET - pe=pos+pres 


* PRINT 


INK 


6;"tnait a wc^ent" 


310 IF INK£Y*="9" RND PEEK pe<- 


5 LORD * 


'Spec Sound "CODE 


24,5 THEN POKE pe , (PEEK pel +10 


6 REM run 1G 


if stopped 


320 IF INKEY* = "4-" RND PEEK p£> = 


10 BORDER 7: 


PfJPER 7: INK 0; C 


10 THEN POKE pe t (PEEK pe J -10 


LS : POKE 65166,0 


330 IF INKEY* = "©" RND PEEK. pe< = 


12 DIM 3 


C9> 




254- THEN POKE pe, (PEEK pC* *1 


15 LET pres=23295: LET 5£=0: L 


3*0 IF 1NKE!Y$^'S" BND PEEK pe > = 


ET b = 12 






1 THEN POKE P« , (PEEK pftJ -1 


IS FOR Z = 


si TC 


9 : READ X : LET d 


350 IF INKEY(= ,, f OR INKEY »="T" 


t Z ) =X . NEXT Z 




THEN BEEP .5*1: POKE (prest*» ,fi 


1- DflTfi 5,6,6 


,9, n,12, 1*,1S,17 


55: POKE (p res +6 J ,265: GO TO 190 


19 PRINT 


INK 


4.; "ttttttttrttttt 


360 IF INKEY$="«" OR INKEY*="M" 


ttttttttttttt+ftft" 


THEN GO TO 600 


20 PRINT 


INK 


ljTflB 6j "Spec trua 


4B0 REM 


sound fx" 






*90 PRINT RT atposi.3;'* "; . P 


30 PRINT 


INK 


2; TRB 6; "© RS 2S-/ 


RINT RT atpos) ,6-(LEN STR* (PEEK 


26. 12 . 1982' 


T 




pen; INK 1; PEEK pe 


4-5 PRINT 


INK 


4-; "++**+?^f ttfftt 


500 GO TO 24.0 


^ + +ttti , t ^ t ^ tJMtlt ,^^ i . - 


600 INPUT PRPER 2; INK. ~7} " ni»b 


4-7 PRINT 






er? " ; s e 


S0 PRINT 


TAB 


bj "starting point. 


60S IF se>27 THEN GO TO 600 


m 






610 LET pressgjse+23295 


60 PR INT 


TRB 


b; "speed" 


620 FOR a=l TO 9: PRINT" RTF a t a> 


65 PRINT 






*3; " " ; NEXT a 


70 PRINT 


TRB 


b; "Lowest Pi tch < 


62S POKE 65186, se 


1> " 






630 GO TO 190 


60 PRINT 


TRB 


b; "highes t pitch 


700 REM 


11} *' 






710 INPUT PRPER 4-; INK 7; "FfOl 


85 PRINT 






which number (inc.J?"; froa 


90 PRINT 


TRB 


b; "Lowest pitch ( 


720 INPUT PRPER 3; INK 7; "TO Wh 


2 J " 






i ch nun be r ( i r> c - >■?"; t o 


100 PRINT 


TRB 


b; "highest pitch 


730 LET StBrt^3g96t9*ffo*: LET 


(2> *" 






tO = (tO-ffOU *9+9 


110 PRINT 






7*0 input "naie?";ts 


120 PRINT 


TRB 


b; "reverse 1 13 " 


750 IF t *="" OR LEN t*>10 THEN 


130 PRINT 


TRB 


b; "reverse: i2> " 


GO TO 7*0 


135 PRINT 






760 SRUE t*CODE start* to 


14-0 PRINT 


TRB 


b; "length of inte 


770 GO TO 190 


r rupt" 






800 REM wove 


150 PRINT 


INK 


2, TRB b; " Ci f th 


S10 INPUT INK 2, move frOB? ";s 


en ien-3 th=S) " 




ta : 


160 PRINT 






620 IF Sta<0 OR Sta>27 THEN GO 


170 PRINT 


TRB 


3; INK 7; T*f}¥>ttt 3 


TO 610 


j " press " 


• p." "■ 


to hear sound " 


S3© INPUT ink a; "aove to? ";sta 


190 PRINT 


RT 5,0; " ": PRINT fi 


2: 


T S*0J INK 


2; se; " : " 


64,0 IF Sta2<0 OR Sta2>27 THEN G 


200 FOR a 


=1 TO 9.* PRINT AT aCaJ 


O TO 610 


,6-(LEN STR* (PEEK (pres+a)>U X 


650 IF Sta=Sta2 THEN BEEP 1^-10 


NK l; PEEK 


tpres +aJ 


GO TO S10 


210 NEXT 


3 




655 LET se=sta2 


230 LET pos=l 




660 LET Std =23296+5 t 3 *9 


24-0 IP INKEYS = 


= "7" RND pos>=fi TH 


670 LET Sta2=23296+sta2*9 


EN LET pos 


=POS - 


-1 


SS0 FOR Z=0 TO 8: POKE (Sta2+Z) 


E50 IF INKEY*: 


-**e~ HND pos < ==© TTf 


,PEEK CSta+Z); NEXT Z 


EN LET pos 


cpOS +1 


690 BEEP -6„-20 


255 FOR Z 


=1 TO 9: PRINT RT d(ZJ 


695 GO TO 610 


■j - >■ •■ . 


NEXT Z 


999 REM 


'260 PRINT 


RT «(po&) /?; INK 4.^ " < 


1000 CLEAR : BEEP 1,-10: BEEP 1, 


"; INK 2; " 


tt * 


INK li ">" 


-20: SRUE "Spexsound2" LINE 1; S 


270 IF INKEY S- 


= "" THEN GO TO 270 


RUE "SpeC£OUnd"CODE 65002,280 



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REAL APPLICATIONS TAPE ...£11.44 

MASTERING MACHINE CODE....... .....£ 7-50 

Prices are for buiit items, Postage 40p under £4.00. 

Export postage fsurf&cttj £7,80. Send 5AE for full catalogue. 

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ZX81 AND SPECTRUM 



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VOUft COMPUTER, APRIL 1983 131 



John Dawson looks back 
at the days when every 
byte mattered, in his 
history of software. 

THE EFFORT required 10 write software has 
been a matter of concern since 1946. At that 
lime, M V Wilkes built EDSAC - Electronic 
Delay Storage Automatic Computer — with a 
team of helpers at Cambridge University 
primarily to permit program development. 
After 1949 this work concentrated on the 
construction of a library of mathematical 
subroutines, Wilkes said that "there would be 
almost as much capital sunk in the library of 
subroutines as in the machine itself, and 
builders of new machines in the future might 
wish to make use or the same order code — 
machine-code operations — as an existing 
machine in order that the subroutines could be 
taken over without modification," 

Like the first Manchester and Cambridge 
computers some early microcomputers had so 
little memory that hardware was used to start 
the machine from the first instruction. These 
front panels allowed the operator to load 
binary values into the accumulator and other 
registers. Switches were set to identify the 
address in the memory and the data which was 
to be placed at that address. The address 
switches were then incremented and the new 
data placed at the next location. By this 
laborious method it was possible to place a 
short program into the computer's memory. 

In Faster than Thought - B V Bowden, 
Pitman 1953 — it is said "In previous 
machines the input to the machine had been 
directly to the cathode-ray tube store from a 
binary keyboard, and output had been by 
inspection of a cathode ray tube monitor. For 
this machine — the second 1949 computer — 
input and output routines were developed 
which enabled teleprinter equipment to be 
controlled by the machine." 

This was 9 great gain in productivity. 
Remember that the original input looked like 
figure 1 and you will have no doubt that high- 
level languages are a great boon to any 
computer programmer. 

At Manchester University, R A Brooker 
developed the Autocode system which was 
intended to be a simple, easy to learn 
programming system for scientific users. 
Autocode concealed much of the magnetic 
drum transfer details from users allowing 
them to concentrate more on the purpose of 
the program — the solution of a mathematical 
problem. Autocode provided floating point 
operations and standard instructions to take 
information into the machine from a punched 
paper tape j output ting the result to a tele- 
printer. Fortran — formula translation — often 
referred to as the grandaddy of high-level 
languages did not appear until 1956, two years 
after the introduction of the Autocode system, 

All high-level computer languages translate 
the instructions that you or I can understand 
easily into a long series of machine-code 
instructions which appear to the computer as 
ones and zeroes. However different the high- 
level language looks, the translation produces 
the same machine code and the operation of 
the central processor unit is precisely the same. 




SOFTWAR 



Why are there literally hundreds of high 
level languages? Some were written for special 
purposes and arc difficult or impossible to use 
for anything else. Graforth, for example, is a 
special purpose version of Forth developed for 
drawing pictures and graphs. It would be 
almost impossible to use Graforth for office 
accounting or the continuous control of an 
industrial chemical plant. Other languages 
were cramped or limited by the hardware that 
they were designed for. 

Lisp was made to work — or implemented 
— first on an IBM 704 and some of the 
instructions in the language take their names 
from registers inside the computer where the 
results were to be found — CAR and CDR for 
example — contents of the address part of 
register and contents of decrement part of 
register. You might reasonably have come to 
the conclusion by now that a great deal of 
software and many of the languages it is 
written in are primitive. This is correct. 

It is true that the technical revolution has 
continued with the development of 16- and 
32-bit microprocessors but it is also true that 
there is, at present, no significant software 
written specifically for these new CPUs and in 
the microcomputer world we are only 
beginning lo scratch the surface of what can be 



done using old faithful processors such as the 
6502, the 8086 and the Z-80. 

The reason for the failure to advance at a 
comparable rate in software is merely that 
writing programs is labour intensive, difficult 
and very time consuming, Programs are 
written either by one person or by a team of 
programmers working to a common plan. 
Teams take longer to complete a project than 
you might expect because of the overhead time 
lost in managing the development of the 
program, making sure that various pieces fit 
and each section is built according to common 
design principles. When the development time 
runs into man, or woman, years, a single 
designer/programmer might never finish the 
task or might Tail to appreciate some aspect of 
the program that will prevent it from ever 
working correct IV- 

The permutations of the various branches 
and choices that are made in any significant 
program are so numerous as to effectively 
prevent comprehensive testing. Remember 
that at a microcode level even the designers of 
the chips themselves make mistakes. The Z-SO 
CPU made by Zilog contains a number of 
unlisted instructions which were dropped 
from the final specification and may or may 
not work on the chip you possess. 



122 YOUR COMPUTER, A Pftlt, 1 983 




the name was shortened to Forth — another 
good example of hardware dominance. 

Forth is a threaded interpretive language — 
TIL — and this means that the program that 
von l. l xi\ uiL 1 i:onsiMs oi .: succession ui calls 10 
addresses of lower level instruction. Those 
instructions may, iti mm, call other instruc- 
tions at the same level or at a lower level until 
machine code instructions arc reached. 

Forth has given birth to a family of 
languages. Stoic is a CP/M version with some 
advantages, the source program takes up less 
space and CIVM. files arc fully supported, 
while BCPI- — Basic Common Programming 
Language — is an austere TIL with a high 
degree of flexibility and little error checking. 
Program development tends to be faster than 
average using TII-s because the nature or the 
language leads to a modular programming 
style which, in turn, allows easier debugging 
of sections of the program as you proceed. 

The ease of descent into assembly language 
rod the high level constructions such as If- 
Then- Else and Repeat-While often provided 
in TIL assemblers make Forth and its relatives 
suitable for on-line as opposed to batch 
processing. Programming iti a TIL is a matter 
of extending the dictionary by building new 
words out of words that already exist and this, 
I believe, makes the language ideal for 
programming by people who art disabled, A 
microprocessor-based aid for a disabled person 
could be easily customised to suit the 
particular requirements of (hat person and 
could be altered from day to day by the owner. 

Some people believe that as Forth becomes 



more popular so the need for assembly 
language programming will disappear. While 
it is true that Forth has a wide dynamic range 
— it allows you to move from a very high-level 
program to naked machine code entirely at 
will — there is a time penalty to be paid each 
time a new Forth word is executed. For words 
containing short sections of machine code the 
time overhead may be greater than the 
execution time for [he actual operations that 
you wish to carry out. 

A macro-assembler, on the other hand, 
bridges the gap between a straight assembler 
producing one machine-code instruction for 
each line of assembler code and high-level 
interpreters that will initiate several hundred 
machine code instructions for each line of the 
source program. A macroassembler allows 
you to define a group of machine code Lnst rue- 
lions by a name- You may then use the name 
in your program as a single line and when the 
source code is assembled to produce an object 
program that will run on the computer all the 
instructions that were included in the group 
are inserted into the object program. 

The advantages of this facility arc immense. 
If you make a mistake in ihe method you use 
to multiply two numbers then you need only 
correct the instructions in the macro and 
wherever that macro-instruction h used in the 
program it will be put right when you re- 
assemble the program. A good macro- 
assembler will allow you to "nest" macro- 
instructions so that one macro can call 
another. This feature allows you to build 
higher and higher level mac ro-instrucf ions .H 




AND ALL THAT 



The 6502 CPU actually contains a mistake 
in one of the listed instructions — JMP (jocFF) 
where the xx represents any page number, 
does not work correctly. If 'xxFF' is 'SOFT", 
for example, the instruction should obtain the 
address to jump to from 50FF and 5100. In 
fact, (he 6502 chip uses the values in 50FI- and 
5000 to form an incorrect address 
combination. 

Assemblers are used widely by programmers 
who need detailed control over the operation 
nf ihe computer because the application they 
arc working on is lime critical or because they 
need to control sophisticated peripheral 
devices. 

Forth was written by Charles Moore over a 
period of several years, although the language 
is dated formally as originating in 1969. 
Working at the National Radio Astronomy 
Observatory, Charles Moore wanted a new 
high level language to allow easy communica- 
tion between the observatory instruments, the 
computer and the astronomer, the computer 
user- The IBM 1 1 30 machine used in the 
observatory was a third generation computer 
and Charles Moore was so impressed with the 
results of his work that he called it a fourth 
generation language. The IBM 1130 
permitted only five-character identifiers and 



Figure h 




. 


6502 CPU Instruction 




Binary representation 


Decrement Register X 




1100 1010 


Load Accumulator with Zero 




1010 1001 0000 0000 


Load Accumulator with 1 




1010 10010000 0001 


Load Accumulator with the contents of 






Address 10GQ Ha*. 




1010 1101 0000 0000 0000 0001 


Jump to Subroutine el 4040 Hex. 




0010 0000 0000 0100 OOOO 010O 


Expressed in hexadecimal notation the 


long Strings of ones and zeros become more easily 


manageable — the instruction to decrement 


register X is expressed simply as CA. 



Below; EDSAG in 1949. Above toft, the Manchester Mark t. 




YOUR COMPUTEH, APRIL 19B3 123 



As from April 

there could be a 
/1/fWmaaazine 

in your li 



L45d 



&i*£nal 9 * 



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microcomputer hardware and software and 
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• Micro Business is the magazine which 
makes sense of the micro scene, identifying 
the pitfalls and explaining the complexities of 
the microcomputer jungle. 

• Micro Business is produced by the 
publishers of Practical Computing; Your 
Computer; Systems International; Computer 
Weekly; Electrical & Radio Trading and 
Electrical & Electronic Trader — Britain's 
leading journals in the computer and 
electrical retail markets. 



# Micro Business will bring new hardware 
and software products to the attention of 
dealers and retail outlets throughout the UK. 

That all adds up to an effective marketing and 
sales aid for companies producing 
microcomputer hardware and software. And 
an important source of market information 
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dealers who are selling direct to the general 
public. If you fall into either of these 
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I 



To; Chris Hipwell, Publishing Director, Micro Business, Room 309H, Business Press International, 

Quadrant House, The Quadrant, Sutton, Surrey 

Name = 

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microcomputer hardware and/or software products. Job Title 



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I2fl YOUR COMPUTE*. APFHL 19S3 



"IT LOOKS NICE BUT WHAT 
THE HELL (AM DO WITH IT?" 

Every 2 x SPECTRUM Prlnt'n Plotter Jotter Has 100 pages of finely 
printed screen grids, 

50 For the high resolution screen. SO for the normal character 
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with these at your disposal you can plan practically any graphics print- 
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The nign-resoiudon plot grid snows every one of the 45,OGO pixels! 
Every one printed, Everyone with its co-ordinate numoers. This gives 
you enormous graphics power to DRAW, plot. CIRCLE, plot over and so 
on I n any position or screen tan tldl ng up graph I C ti raw) ngs, Char ts, maps 
... in fact anyth Ing witnout the com p I Scat Ions of guesswork. In teger 
out of range, Of wrong ly posit loned p Ixel colours wh I ch change PfftNTed 
(NK characters! 

The normal character PRINT grids on the other hand will allow you to 
be specific about print at, tab. print over, screens and INK paper in 
direct co-ordination with PLOT , , . vou see every page is printed on high 
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And there? another bonus, because each page contains 24 User- 
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PROGRAMMING 



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"NOW WHICH KEY DO I PRESS 



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Ever forgotten wh ic h key to press when piavl ng a game? 
Do you suffer from a mind-boggling mass of programmed keys? 
Do you write programs that use different keys to perform various 
functions? if so, we have just the thing for vou rzx spectrum. 

a pack of Prtnt'nPiotter Keyboard overlays. 

Just write the function or functions under each key you prog ram and 
keepthe overlay for the next time you play the gsme. 
of course there's lots of more uses you win find f nr our overlays, user 
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busi ness uses ~ to na me just a few. 

Tnere' s t en overlays to a pac k — so yo u can prog ram with impu n ityl 
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Each overlay is printed with the cursor movement key directions ana 
there s room f 



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" PRINTER PAPER THAT WORKS? 
I DON'T BELIEVE IT!" 

Five rolls of our printer pape r wi II on I y cost y o u £ 1 o. 9 5. And you w i i i 
gain a great deal morel it prints beautiful ry. it's not too thick its not too 
Shiny. Print Is black — not grey, it actually feeds through the machine! 
see for yourself. Only £10.95 for S roils. Beware of expensive imitationsi 



"ZX81 GRAPHICS BETTER 
THAN SQUIGGLES AND BLOBS? 

Disappointed with ZXS1 Graphics? Perhaps you haven t explored the 
vast possibilities. 

Why not invest in a zxbi jotter, film and our guide zxsi Graphics 
programming made easy"? 

The jotter is a 100 page pad of PRINT qrids and plot grids with all 
numbered co-ordinates, The FILM Is a re usable matt transparent 
polyester version of the grids which can be drawn-on and used again . . . 
Ideal for overlaying and copying 

Th e 24 page f u 1 1 co i o u r g ui oe wl 1 1 show you how to use the JOTTER and 
film to produce perfect 1 ow resolut Ion graphics on your ZXSI I 

so stop sctLiiggiing. Get a set now I 



"lAJUCDE rAMirCTTUCM7" 2X spe ctrum jomR^9.9seach. 

Ill ICftE Vrlll I UC I ICIf I f ZX SPECTRUM KEYBOARD OVERLAYS @ £2.95 D6r pack 

Post now or can at one of our retailers! Mw*wm£n5& ^ *** 

Post to Print n' Plotter Products, 19 Borough |gj rlms^s e£h 

h ig n St , Lond on SE 1 95E , 7^ CHA pm^s prog&am m i ng guide ■ @ £ i .to each 

ZX PRINTER PAPER @ E 10.95 per five rolls 
Namp- 

™" c — ■ — ,T * ■■' ■ Remittance encloses. Please dill my Access/ 

Barciavcard^ Visa f Mastercard NO: 

Address: 

Please note: Price Quoted include vat. pup for 
uk aei series. 
Y Overseas order please add 25*b for additional 

Surface Mali 



Vou can s« and ouv most of ou r products at 

w. H. smith (Computer stores) 

Buffer Micro iStreatham) 

Mlcrowareneicesten 

Oennys Book shoos i London £C1 1 

Personal computer Services iDarwen Lanes) 

reiford Electronic* commuting (Shifn.aU) 

Georges aoohthop (Bristol) 




NovVs the time to 
subscribe to Your 
Computer, Britain's 
biggest selling home 
computer magazine. Because 
as from the April issue we will be increasing the price 
to keep pace with rising production costs. 
Your Computer is fantastic value for money. The 
December issue consisted of 1 64 pages packed with 
computer and software reviews, a special games 
section with listings for all the major home computers, 
articles on writing programs yourself, three features just 
for ZX81 owners, and Response Frame — the page 
which answers your questions. All this, PLUS a free 
Flexidisc containing games for the ZX81 , Vic 20 and 
Sinclair Spectrum. The price? Only 60p, 
And that issue was typical of the value which Your 
Computer readers have come to expect. Rather than 
cutting down on editorial and on the lively presentation 
which makes Youf Computer so readable we are 
dedicated to maintaining our editorial standards. But 
with production costs rising we can onfy maintain 
quality if we increase the price of the magazine. 
We know you'll think it worth paying the little extra 
we'll be asking because Your Computer will still be 
unrivalled value for money. Meanwhile, a subscription 
taken out NOW at the old rate of only £8.00 for 1 2 
issues will save you money throughout 1983 — and 
beyond! 

Just fill in the coupon and return it to us with your 
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To: Subscription Manager, Your Computer, 

Business Press International, Oakfield House, 
Perrymount Road, Hay wards Heath, Sussex 
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I wish to save money by taking out a subscription to Your 
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126 YOURCQMPUTER, APRIL 1983 



BASIC DICTIONARY 

This dictionary, compiled by Tony Edwards, will explain the function of common Basic words as 
used in popular machines, enabling you to work out your own machine's equivalent. A useful 

complement to our recent series on Basic dialect translation. 



BASIC DICTIONARY 



TAN The function which returns the 
tangent of its argument. The argument is 
usually expressed in radians. A standard 
ANSI word. 

TEXT The Apple II command or statement 
which changes from graphics mode to text 
mode. 

THE The PDP-SE abbreviation for THEN. 

THEN Part of the IF .... . THEN statement 
which is used to indicate the next operation 
scheduled, once the IF condition is 
satisfied. A standard ANSI word. 

TI The Commodore Pet abbreviation for 
TIME. 

TIM Another common abbreviation for 
TIME. 

TIME A command and function used to 
return the elapsed time in seconds from 
some reference point. Not to be confused 
with TIMES. 

TIMES A function which returns the actual 
time of day. Not to be confused with 
TIME. 

Til The Commodore Pet abbreviation i'oi 
TIME! 

TO Part of the FOR . . . TO . , .STEP 
statement. 

TOP A function used in BBC Micro Basic 
to return the address of the first free 
location after the end of the current 
program. 

TRACE An Apple II command or 
statement which causes the computer to 
prim out line numbers as each one is 
executed. It is normally used during de- 
bugging only, 

TRACE OFF The command or statement 
whkh switches ofFthe TRACE Command. 
See also NOTRACE. 

TRACE ON A command or statement 
similar to TRACE. 

TROFF A common abbreviation for 
TRACE OFF 

TRON A common abbreviation for TRACE 
ON. 

TRUE A special function used on the BBC 
Micro which returns the logical true value 
{- 1 J when called. 



U 



USR A function which transfers control 
from a Basic program to a machine-Code 
program resident elsewhere in the 
memory. 

UNTIL Pari of the REPEAT UNTIL 

statement. 



VAL A function which returns the num- 
erical value of a number expressed as a 
string. 

VLIN AT An Apple II statement which 
draws a vertical line at the specified 
column position. The arguments after 
VLIN designate the start and end points 
and the argument after the AT designates 
the column. 

VPOS A function which returns the vertical 
position of the cursor. The screen top is 
numbered 0. 

VTAB An Apple II command which speci- 
fies the line on which the next output will 
commence. 



W 



WAIT A command or statement which 
causes the computer to halt execution for 
a specified period of time. 

WIDTH A command or statement used to 
pre-select the printer carriage or VDU 
screen width. 

WRITE The Apple II command or state- 
ment used to output on to disc or cassette 
storage material!. 



Non-alphanumeric 
characters 

As well as the use of reserved words, 
computers also use non-alphanumeric 
characters as operators or abbreviations. To 
conclude this dictionary these are listed — in 
no particular order. 

n {quotes). The almost universal use of 
quotes is to delimit the range of a String. 
It is an ANSI standard operator. The 
Atom uses a single quote for this 
purpose, 
„ (comma) An ANSI standard operator used 
as a delimiter in lists. The TRS-80 uses it 
as an abbreviation for THEN and to 
separate otherwise ambiguous lists. Palo 
Alto Tiny Basic uses the comma to allow 
the placing of more than one statement 
on a line. 
. (full stop) An operator used by the 
TRS-80 level . 1 to identify abbreviated 
commands, statements and functions. It 
can be used in level 2 as the argument of a 
List or Edit command and in this case 
means "last line operated upon". It is 
also used as the decimal point. 




BA *IC DlCT,Of 



; (semicolon) A standard ANSI operator 
which allows several output sections to be 
joined together on one line. 

(...) (parenthesis) The operator used to 
determine the order in which operations 
are performed. The innermost pair of 
parentheses arc performed first. 

[ - , . 1 (square brackets) In many 
computers square brackets are inter- 
changeable with parent hesis. The BBC 
Micro uses square brackets as delimiters 
for assembler statements. A single left 
square bracket sometimes represents the 
exponential ion operator. 

= (equals) The ANSI standard mathemat- 
ical equal sign, ll is also widely used as an 
Assignment operator, sometimes with a 
preceding LET, Most computers also use 
it as a relational operator to compare 
numerical values or strings, 

1 (caret) The standard ANSI symbol for the 
exponentiation operator, 

T (up arrow) Another symbol sometimes 
used as the exponentiation sign. 

< (less than) The standard ANSI symbol 

for "less than". Used when comparing to 
numeric values. Many computers can use 
this to compare strings and, in this case, 
each character in turn is compared from 
the left to assess alphabetic order. As each 
character is compared individually and 
the order is decided by the first non- 
identical character, the length of the string 
is not a factor. Can be used with a" + " to 
tc present equal to or more than. 

> (greater than) The standard ANSI 
symbol for "greater than". Used when 
comparing numerical values or strings. 
Can be used with a " = " to represent 
equal to or more than. 

<> (not equal to) The standard ANSI 
symbol for "not equal to". Used when 
comparing numerical values or strings. 

X (not equal to) A symbol sometimes 
used instead of <>. 

< (equal to or less than) An alternative to 

< = used on some computers. 

(equal to or greater than) An 
alternative to >= used on some 
computers. 

9* (not equal to) An alternative to <> used 
on some computers. 

* (apostrophe) used on many computers as 
an abbreviation for REM. Used on 
the Atom to enclose strings and on the 
BBC Micro to produce new lines in 
PRINT or INPUT statements 
Sometimes called a "single quote". 



YOUR COMPUTER. APRIL 1983 127 



ZX81 AND SPECTRUM 
HARDWARE 

ZX81 KEYBOARD 



FULLY BUILT! 




• Full size keyboard 

• Plug in — No soldering 

• Full Repeat on all keys 

• Single keys for F4UB0UT, EDIT, FUNCTION and CURSORS 

• Large space and newline keys 

• 2 Shift keys 

We also are stockist for Rodditch Electronics. 
Sec their Ad in litis issue and Feb S3 page 36. 
Our prices are 10% leas for all their products. 

Metal case to hold our keyboard, RAM pack, ZX81, PSU and 
strong enough to put TV on top. £26. 

Postage 40p under £4. Export (surface) £2. 
Send SAE or 20p for catalogue. 
Cash with order w ACCESS. 

HARRIS & LOCKYER ASSOCIATES 

33 Pedmore Close, Woodrow South, 

Redditch, Worcs B97 7XB 



SPECTRUM 
48K 



SERIOUS APPLICATION PROGRAMMES 



ELECTRONICS 



£5.95 



tver built i dtfitil *l*ctrorile circuit tfc*t didn't mrkl Nov ehu lu^hl* 

v.iJjpr»fi»n»Vv« dailan ps-iiftE*™* Cfi#bia» fou [□ Jtiu a clTcult <H±e,mei an th. 
Li-rtirn, gtlM itgp.ijTj ctJTper.an: ■ , including "•ntlUori, lojie gatai, dljtl, 
trlBL-i, :hyr£»ce-T» *lc ate (Sr dr-tlntC pmtiala *t* «ii»d*. Thai* bit fc* 
rftt*vc4 O.E1 »frrrn :f 7*qulcaii. OnCa corplm* In* c<j«ipuL*tf wit) acliVala Ch* 

- ?■; dtiplir [^ wolds' l* M *li thiovihovtt Tfour circuit *jy p» 
d*'*mv*t*4. ncdlfiad ind r«-Mll.**Tt*d a i*y«4 en '.*>• 1(H fU£ur> *ir and 
ciiplrd to ifta BfiRHH. hi tnviluifrlc «|<J ;c ;)■.* d*H(r*r «f ^Hi;*l *3rciTun 

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ilti (r«o tKe »l«fO«n in « r<i*«nfu! of d*n»ly ■*(k«4 IntvTcwntetHd 



NUMERIC 



£5.95 



A nvl ii-lu.neiiM> well* twllite p* £■*« at«>* . 

it will *n £nlv* anr aquation lor a aLnjlr imkiWVfl. 

?, Jiae th* iT*ph af pry function - yau ™*jf *»pand or contract th* 
nil jnd lltir rh* lrtci*lr*;Yli In ftid*? ;« OfcliLn lla* b**l 

* *»i***ai*iic*> fi vmr 'ubj-ioh. 
C. ialiir aiauLtanasua and quadrille *«ultl6n*. 
d. Solvt iliht JfjL* 5Tl*ve.»«- 
*. Find jt 1 -fan L". C Man and *ian4atd ^tvltllen fef t lire «f taaTAttir 

II uill do cr* iibi (er H*l lltti plui finding th> coafflcianl 

of correlation Human ".ha*, Graph*, tin be predtitd for yeur dill 

afitrft to* t-raa i-ndaid Saviiclon. Cutvai. 
All dUplayi 4*» S>* £a«l«4 EC- th* ?Tll!:#T l( laquind* 

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on a r,prc*l Sfaccruji. Theae »^s»ra jiennacui* ate aitricaly uaa: frt=r.Jl^. 
coca vith ccn.p(anar.ilw« tni tiwt Irn* ins after I'iCll^elaa '.Oft Auttifrul M 
cov*r In thii aitvart laaaan-. CxcapiionaJ valu* (or nonaj. 

riaaaa i£ata £tn)lu|<T tiffi 
Qwqnifa r ayj^! T ioi 



(p?ctr 



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2 MULL CLOSE 
OAKLEV 
BASINGSTOKE 
HANTS 



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All price*, include VAT and poa and ptckaguig All jskim tnc)ud> * fuD |hi e^uuint>v 
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Addtess 




Program Duplicating 
on cassettes? 

500-20,000 Copies 
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J 23 V OUR COMPU T &R APRIL 1 983 



RESPONSE FRAME 



Do you have a problem? Your manual is 
incomprehensible or you just cannot get the 
hang of that programming trick you tried — 
whatever it ?s, Tim Hartnell will do his best to 
answer your queries. Please include only one 
question per letter and mark them "Response 
Frame". 



BLANK STARE 

■ 1 cannot get my Spectrum to 
recognise the difference between 
si blank space — either as OIKS 
20, 1, 32 or CHKS 143 — and an 
imprinted character. The 
ScreenS fundi nit (rents the in nil 
as 32. If an Ink is specified 
beforehand, then I can differ- 
entiate between them tiling Attr, 
However, if 1 just print up an I "\ 
Video or t i-sJiifi t-M black square, 
Ailt treats it as If i I were blank. 

What can I do? 

Julian Vincent, 

Eariey, Raiding. 
It is unfortunate i har it is 
impossible to detect use t -graphics or 
blink.! with SereenS. It -seems an 
oversight when designing the ROM, 
as it is probable thai Screen} would 
find its widest application in moving 
graphics programs when you need to 
detect whether two object* have tun 
into each other or have, say, run otT 
the edge of ■ track or road. I get 
around ihe problem by using some- 
thing other than a blank, which still 
prims up as a satisfactory object, 
You will find that the capital X 
very well for walls and things that 
you otherwise would prim us a set lcs. 
of inverse space*. Use Inverse 1 in 
the line thai is printing the Xs, and 
detect them just looking for the X, 
The full stop can also be used, or the 
slash. Experiment with the letters of 
the alphabet and the symbols, to find 
one which does not look too much 
out of place in your program. 

ATOM TOOLBOX 

■ I have a 12K plus 12K Atom 
and am contemplating an 
expansion of its facilities. Would 
you advise me to buy a 
programmer's toolbox ROM, 
considering the availability of 
the disc pack for the Atom, or to 
upgrade it by inserting a BBC 
ROM, considering the further 
expansion of the BBC computer? 
If I choose the latter, it it 
possible to upgrade it further to 
BBC model B? 

WLuk, 
Oxford. 
You Do not explain the main 
purposes for which your computer is 
used, and this has some bearing on 
the answer to your question. The 
"BBC upgrade 1 " does not turn an 
Atom into a BBC Micro, but simply 
gives it access to a large pan of BBC 
Basic, but noi at the same speed as 
the BBC Micro. If you are 
sufficiently advanced in pro- 
gramming the Atom to contemplate 
purchasing a utility ROM such as 
you describe, it is likely that you 
would be best advised to stick with 



the Atom, and continue to develop 
your skills on that, rather than 
convert it to a machine which is 
neither one computer nor the other, 
and have ro re learn many of the 
techniques you have acquired to 
date. 



PLUG BUG 

II am 12 years old and own a IK 
ZX-Sl which works perfectly, 
except sometimes when first 
switched on. I have found that 1 
can correct its odd behaviour hy 
fiddling with the power input 
plug lo the computer. Can you 
tell me what is wrong? 

Michael Rabhetl, 
Huntingdon. 
Thk stXKtr for the power supply — 
and indeed I'ur Mic and Ear as well 
— tends to work loose, as you move 
the plugs in and out a lot. The 
answer is simple. Get art electrician, 
or a friend who knows how to do 
such things, id bend the metal inside 
the plug socket slightly, so it grips 
lite plug firmly, As « general rule, 
you Should not remove the plugs 
more than you have to. I suggest 
leaving them in place nil the time, to 
minimise wear on the sockets, 



SLEEP NO MORE 

■ l won a ZX-81 and have 
recently been writing a games 
program which involved, in 
part, negotiating a two- 
dimensional matt, The mare is 
randomly generated, with its 
only record being in the display 
file. By using the common 

PEEKIPEEK 16396 

256-PEEK 163391 
I thought that I could prevent the 
JnfctyS operated figure 1 from 
passing through — and erasing 
— the walls, which are made up 
from graphic spaces. For a 
while, I thought this had been 
successful, then discovered that 
by rapidly pressing and 
releasing the controlling key it 
was possible to pass through the 
wall with ease. I have tried in 
vain to solve the problem but it 
seems to be beyond me. The 
above is the only Peek routine I 
know. It works perfectly if 1 just 
want the program to stop when a 
wall is hit. All progress on what I 
hoped would be one of my bent 
games has been halted because 
of this bug. E am desperate and 
without steep. Can you help? 

Marias Htintey, 

Chipping Sodbu ry, 

Yot'R pff.k routine is correct. The 

most likely explanation for its failure 

under certain circumstances is that 



you are not checking the result of 
this Peek every time you cycle 
through the program, because there 
arc two routes through it. Perhaps 
you are lumping some of it when the 
InktyS is not one of the vital 
readings, and one of the routes 
misses the routine Check this by 
including it in another pan of the 
program, and make sure the line 
which is needed as welt — the Print 
At ending with a semicolon — is I 
atwtiyt immediately before the 
Peek/Peek, 



CHEAP MEMORY 

■ I would like lo expand the 
memory of my Vic-20, but it is 
very expensive. Commodore 
charges over £70 for its unit. 
While looking through a re-cent 
edition of lour Computer I saw 
an advert for a I6K unit for the 
Vic-20 for less than £4(1. Does 
this unit do the same job as 
CommodorcS unit? Arc there 
any catches In buying the cheap 
memory? 

Ricky PedeJty, 
Skeppy. 
1 BOUGHT ONE of the cheaper 
memory units in August last year, 
and was unable to get it it* work, I 
returned it, and asked to see the 
replacement working before 1 
accepted it. I was happy with the 
demonstration in the shop, and since 
then, have had no problems with the 
unit at all. There is no indication, in 
terms of performance, that the 
cheaper memory is not doing every- 
thing the Commodore unit would 
provide. I suggest the dud unit I got 
the first time was just luck of the 
draw. Perhaps I would have been 
just is unfortunate with a 
Commodore expansion. 

PICK A MICRO 

■ I'lease help 1 . I often read your 
magazine, which T find 
fascinating, particularly the 
evaluations of micros. However, 
there now seems to be a 
bewildering range of micros 
available- I should be very 
grateful for any advice on the 
moat appropriate one for my 
own needs, which are at least 
32K of memory, expandable; 
high- resolution colour graphics, 
with the possibility of 3-D 
graphic*; scientific use — I am 
not particularly Interested Id 
games; real typewriter key- 
board; ability to turn a cassette 
player on and off from the 
computer; usable with L'HF TV; 
a good, clear user manual; good 
colour; and under £400, 

S ]f Pearson, 
Lectin 
It SOUND as if you are talking about 
the BBC Micro mode! B. Check out 
the Electron before you make your 
final decision, The highest graphics 
resolution on the model li demands a 
monitor to see the graphics at their 
best, and would be vital for any 3-D 
graphics work. 



MAKING A DIN 

■ I have just ordered a 48K 
Spectrum. The tape recorder I 
wish Us use is a Philips lil--3302, 

which has DIN in put /output 
sockets. As the Spectrum is only 
supplied with jackplug leads, f 
would like some information on 
how to connect up the Sinclair 
leads to DIN leads, 

.'f If Smith, 
Torquay. 
It IS MKfcLV that you will not be able 
to make the conversion satisfactorily. 
The Spectrum demands a high 
output from the cassette recorder, 

such as that which would be used to 
power an external speaker, rather 
than the reduced output for head- 
phones. Secondly, the output from 
the Spectrum when Saving is 
designed for a socket with the 
sensitivity of an ordinary micro- 
phone socket. Speak to an electrician 
about tapping into the extension 
speaker output, and getting into the 
microphone, rather than ancillary, 
input. 

LOWLAND SCROLL 

■ I recently received a 16K 
Spectrum and am Mill discover- 
ing new possibilities. My only 
question so far is about Poke 
23692 which — according to the 
manual — will let the *creen roll 
on and on. I have tried this, bul 
it does not work on my machine. 
Do other Spectrum owners have 
problems with this? 

8 R Stmt, 
Moan sen, 
The hfttietiamit. 
Tilts poke is designed to stop the 
Spectrum printing up Scroll? every- 
lime the screen is Rill, and needs lo 
be positioned within the program in 
such a way that it is triggered fairly 
regularly. I usually use it within the 
master loop of a program, If you still 
get St.'i.iil' irom time to time, scatter 
the line throughout ihe program a 
few more times. The form I use is 
Poke 25692, -I. 



DRAGON LORE 

■ I have recently bought a 
Dragon 32 computer and would 
like to know if you could 
recommend a book on pro- 
gramming in extended Basic 
Also, could you tell me which 
Other computer software is 
compatible with the Dragon? 

MnJBtgg, 
Abergavenny, 
G&tnt. 
It is rare that Tandy Colour 
Computer programs will run on the 
Dragon 12 even in cassette form. 
About the only way to convert 
Tandy software for the Dragon is to 
get someone with a Tandy to 

CSAVfc PROGRAM NAME "A" 
This will save your Tandy program 
in ASCII form, Tutu you will be 
able to load it into the Dragon, If it is 
in machine-code you will not be able 
lo run it at all. 



YOUR COMPUTER. APRIL 1933 129 



DRAGON OWNERS . . . 

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PEPPER'S GAME PACK 
6 GREAT GAMES ON ONE CASSETTE 




MAS7ERSRAIN 

You'll need all your wits to creek ihe computer's code. 3 levels 

of dif lie ulTy. 

PEPPERS BREAKOUT 

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keyboard. 7 Skill levels. 

TERRIFIC VALUE - ALL SIX JUST C7.95 



NAD THE NECROMANCER 

Mad has stolen your book of spells. Track him through the 
catacombs and us? cunning to trap him, but watch out for 
serpents, trolls, gnosis, etc. 

MUSHROOM MUNCHER 

Sie-m the epedemic of blue mushrooms and flying pods. Look 

out for the munch monster. § skill levels. 

CHESSBOARD TRACKER 

Use cunning and strategy to trap the computer controlled 

runner, but beware deadly blockouts n any skill levels, 

CHAMELEON RUN 

The canyon waRs are closing in, can you fly the shuttle io level 

10, 5 skills, 

Available from selected dealers or send cheques /POs made payable to: 

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ARTISTS DESIGNER 

Produce mrrl-caie dsfigrtf in te-ies graphics and »*ve than* On cesselie, FuK fol ol 

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lent mere* Ubefirng Idc If for education, dfr gnw i t . home •noea caprara. E8 99 

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zx 




Serious Application Software for your 
16K ZX-81/ SPECTRUM 16K or 48K 

(Please specify) 
MATHS 

Po» children 5 12 yfwirjitgi * - */, ell with exceptional HELP facility Ifuli 
sfep-by-sieo e-Kplaiwii&osl and opiionaJ entry of units, ihen tens,. £8.00 

SALES LEDGER 

Ideal wnad business system, day book*, statements etc for up io 200 
accounts nO-00 

PURCHASE LEDGER 

Daybooks, remittance aflwcp eic tor up to ZOO accounts. flQ-00 

INDEX/ RETRIEVAL SYSTEM 

r ijj ir ItfviHs o1 data, usual facililits inc search on kuvword or part of word. 
£6 SO 

BRIDGE 

Full scoring system displays and prints lull scoreboaid. locals for b rubbers 
and .ill hands played. 16,50 

MORTGAGE 

How long will any montage be If the rata increases? What should 1 pay if the 
interest rate changes? Mortgage tells vou land motel. £4.50 

RETAIL ACCOUNTING 

FxctHlenl retailir-g systerr. takings product SflhM analyses etc, C10 00 

SHARE PORTFOLIO 

Analyse and trace investments listings by transaction, current holding*. PfitL 
ar^rysisetc, fl&OO 

INCOME TAX 

Ta* code calculation, CAYE checking and net pay calculation for future 

mpnihs. £10.00 



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lOepi [Yd 



42 45 New Broad St, London EC2M 1QY 
(S.A.E, for more details) 



VIEWPOINT 



THE PROGRAM THAT 

VOURrxSftCTnUMHAS 
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Draw complax 3-dirrwiiional object*- View them after rota- 
tion in any or a 1 1 ol 3 dimensions. 
Features 

II Hot At ion in 3 dimensions about a simjle point 

?'■ Rut alien about a linftbatwecn i«™ points 

SJGtiiieintion o' stereo pairs 

41 Vi e w It am &ne poin I iaivj rd& a no : h e r pQi nt 

Ob|fct4 can be stored srpar a tely on I a pe and COpitd to th* /X 

printar 

Wutteo in BASIC tor you to modify to yoof own requira- 

menu 

Ideal tor computer modelling, molecular modelling. CAD pit 

Viewpoint with full instruction and examples 
£6 50 

Jtiit HJfU'ig io wilts mjthini code program*' Th« (deal as 
»en<uPi"for beginners iau lira violin LooVal ineldcliliesmjtil 
olleis 

Works emntiy m decimal |ng hex problem*!, all 2SO in 
strur.t.Dns correctly assembled, supngris, the pSaodO' 
ins'i uctiont EQU. ORG fmullipie OflGsallowedi. OEFB, DE FW 
a nd DE rS : code ca n be as-semtl L*d at a ne Ipcat mr and Ihen re - 
located.: allows a phanunwrc nbels of any tongth. full listings 
of assembled cede and mnemonic* can be output to the 
unr>|tr(, full error trapping wUFi laully in;1rucUon Clearly <' a- 
cated. commenii can be included in the source Me. 
Trie ideal complement io Olcavioiel is Inlrared - an easy lo- 
use disassemble* 

So no w there ' * n □ A ETd to oe i hti mfdetad by mac htna code ■ 
with UUraviolel and Infrared it's child'* play 1 Buy ihem from 
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ULTRAVIOLET £7.50 



INFRARED • £6.75 



All uur Spectrum programs will worts in both 1&K and 4GK 
modeH Pieate send sae for details of Z KB 1 programs 



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130 VOUft COMPUTER, APRIL 1 98 3 



FINGERTIPS 



Fingertips is our regular calculator column 
covering calculator news, programming hints 
and examples of unusual applications. The 
column is written and compiled by calculator 
enthusiast David Pringle who is glad to hear of 
any of your ideas. Your Computer pays £6 for 
each of your contributions published. 



This month I risk the invective of 
readers who tell me the Sharp 
PC- 1211 should not feature in this 
column, "It's not a real pocket 
calculator", they say. Welt, here 
goes anyway with a program called 
Treasure Quest by J V Moss of 
London. 

Fantasy games are increasing in 
popularity, and also variety, but it 
may surprise some people thai it is 
possible to run such a game On as 
small a machine as the Sharp 
PC- 1211 Pocket Computer, 

In the game to be described, the 
player travels through a labyrinth of 
eaves, the object being to find the 
treasure and brims ii out of the caves 
within forty days. 

The labyrinth is represented by a 
seven -by- seven square matrix of 49 
caves. The caves may be empty, or 
they may be inhabited by fairies, 
trolls, giants or dragons. The player 
may move through the labyrinth 
cave by cave, using the commands 
N, 5, E or W, representing the 
points of the compass. Alternatively 
he may rest or fight. 

Initially, the player is in the most 
south-wester ty cave, and he knows 
1 only that the treasure lies in a cave to 
the far north-cast, On finding the 
treasure, he must bring it out by the 
most north-easterly cave. 

The computer keeps a record of 



the days — it takes one day to 
journey from one cave to the next — 
and tells you what, if anything, 
inhabits the cave. 

Trolls, giants and dragons are the 
adversaries, in order of danger, trolls 
being the least dangerous. The 
player can decide there and then to 
fight, which gives him the advantage 
in the conflict. Alternatively, the 
player may try to move to another 
cave, to return the way he came, or 
to rest quietly for a day. If the 
adversary sees him, then he will 
fight, and in this case the opponent 
has the advantage. The adversary is 
less likely to sec you if you rest, or 
return the way you came. 

The outcome of a fight is 
determined using random numbers. 
Fighting uses up energy — as docs 
moving about — which can be 
recovered by resting. If you arc 
injured, it is best to rest in a fairy 
cave, and let the fairies attend to 
your injuries- However, the quest 
must be completed within forty 
days, 

The program use* fill the available 
memory of the PC- 1211. Therefore 
there are no comments, and the 
program must be keyed in exactly as 
written. 

The subroutine at line 2 is a 
random number generator which 
generates a positive integer in F less 



Adventure £r*r» for FC- }2tt. 



1 
2 

1M 

ne 
fee 

.111 

202 

220 
225 

22* 
228 

230 
235 

241 
242 

243 
243 

. SB 

Hi 

;*: 
2?a 

29ti 

see 
aai 



E*e-HmE>-fp|Hr<E*F> -RETURN 
OOSUf 2- tKl><# :HEXT I 
F"3- GOSUB 2'H-F F-3 EOSUB 2 



FKfrO-9 GOTO 1» 

E>EXPCLN< £ + >*S>: 

FOR 1*14 TO 62 H: 

L«8: H»er K'M B-2S: 

fl<46 * Ft? -H* - 6 

IF K - W If FKfi4> > THEN 700 

H*fl<KJ ■ IF H-6 THEH i&S 

IF H'9 KEF 1 PflUSE h EMFTY CftVE" OOTO 223 

KCP t PflUSETflVE CONTAINS A *,A*<H> 

M - M * ] PflU5£»WW";M [FH.44 PflWSE'YQtJR TltC IS UP* 

STQF 

IFKC6 PftUSE-YOU RRE TlftElr 

IMPUT'lHm DO WW BO "■ ■ i 

IF Jl - "FIGHT" THEH 4» 

If St * -REST* LET F - 3' GOTO 3W 

I « 6- IF J» ■ "H" LET I ■ 7 

IF " 

IF k-l>(UtL/?>»?*8 THEN 299 
IF K-INT<H^7>4?«6 THEH 2M 



Jt 
IF ft 
IF St 
JF 1 ■ 
IF K* 



S" LET 1 

'U« LET I 
*" LET J 

e ooto sss 

CM THEH 2^fl 



1 i 



GOTO 228 



IF <*\>62 THEH 298 

- -I IF I - -L LET F - 3 GOTO 278 
F " £ 

IF rt > 1 THEN 33*J 
L <■ I* - li * ] GOTO 2« 
KtP 2 PfiUSE-MO EKtT TO «;J*i 
C * M 2 IF H ■ 9 THEN 22* 

1 • B:IF H > I THEN 3SB 
F - 12 50SU» 2 

JF F < II IF C IS FfluSE-FfttftV T£N2$ VOUfi UtX*H>5" 
6 r Q * @ GOTO 223 

33* LF F ■ 11 PflUSE'FftlBV OlVES VOU" ^RUSE-fl rWtJJC SUORD* 

e - + AS 
■34 6 GOTO 2iS 

35* OOSUl 2 IF F < 2 THEM 273 
MB BEEP 3: FflUSE"h€ SEES VOtT PftUSE-VOU MUST FI&HT" 

I . 4 i GOTO 4ifl 
403 1 - a=IF M - e THEN 22S 
419 ? * 2- GOSUB 2 
413 IF f.*P<f|.H<H*(F'*ls>;ti:>6 THEH 6661 

Cgf &&"**&*)& "VOU KILLED THE 

435 IF 0>1» THEN 228 

440 J*-*": IF GCfl LET J*»"EFIpLV - 

443 FflUSE *BUT VOU ME ':}*>■ MJVftE.tr .GOTO 223 

&W 1EEP 5 PflUSE -V*U FOVHl) THE THEBSURf^ - -JKKf «*"H 

wt4J » I GOTO 229 
7m BEEP 9:fftUSE 'TftSK: PO* IN h ,fl,' EWS* 
710 PRINT "VOU rtftfiRY THE PR! HCESS r ■ : S TOP 

ew beep 5 priht-vou are killebp" 

ue? STEPS 



-ft*<H> BCKJ-e- h*« 



WW processor for Sharp PC- 7500, 


lJ0:fi"fl+JiN£XI S 


i 0: '"«'■: WOIT 0: 


120: IF DOETHEN 50 


CLEftR :OJn T*C 


1^0;D ,H ;CLS : GRAPH 


120?*79; L^i 


I ROTATE 1U-1 


20: 'C : INPUT T*CL 


1 43 J GL CURSOR t0, -3 


JiLPRlNT T*CL> 


3J:50RGN 


;:CS1ZE J: 


150: FOR rl=lTD 5i 


LFRINT LJCS1ZE 


STEP 20 


2.L=L+i:LF 1 


160EFOR K=JTO 12 


30: IF L<121 THEN 2 


1?0:GLCURSQR 





KTJS, 0):LPRJNT 


40; ,H B'":L^L-1:D=L: 


HID* tTSCJ^n, 


LF 2 


20>:J=J + J J 'NEXl 


50;A=1 :E^D:D^J(|stT 


K 


CD*. 73*. 5>; 


180:GLCUR5OR C0, -2 


PRINT STP* E 


4a?:S0RGN : J~J 


S0;FOR B=1+DT0 L 


-J2:MEXT l°l 


78:G*=LEFT* tT*tO 


J30;J=J*12: IF J<^L 


;, 16i:H*^LEFT* 


THEN 140 


tT*CB>, J6) 


300: TEXT :END 


80: IF G*>H*TMEN J 
00 




SBiGOTQ 110 


1 ( f t t ( )»*.-. ^ 


100:Tit0>^T*<:A>; T* 


0H3&4S6tS^ 


(.(i> = T$<>B);T*<.B 


ABC ... K V I 


>^T*C0> 


«* r-t f| A 

A b C " - ■ H«3 



than the initial value of F, using a 
fractional seed: in E. It was 
positioned here because there was 
thought to be a speed advantage in 
executing a subroutine at me 
beginning rather than ihe end of ihe 
program area. 

Line 101) fills the matrix with 
creatures for the new game. Line 
110 $ci5 up the initial values 
including the position of the 
treasure. Line 200 checks if the 
treasure has been brought to the 
north-eastern most cave. If not , lines 
201 to 226 display the current 
situation and line 223 invites a 
response. 

Lines 230 to 255 procc$s the 
response, checking directions to 
ensure that the player can only move 
within the matrix, Line 260 checks 
for moving back the way you came, 
to alter the value of F so I he re is less 
chance of an adversary seeing you. 
Line 275 actions the move. 

Lines J00 and 340 arc concerned 
with "resting", and lines J50 and 
360 determine whether you arc 
spotted by an adversary. Lines 400 
to +45 determine the result of a 
fight, line* 600 to 800 are self- 
explanatory. 

The program could easily be 
adapted To run on other computers 
using other dialects of Basic. On the 
PC-IZII, Beep merely sounds a 
buzzer, Pause displays a line for 
about half-a-seeond before going lo 
the next line. 

Variable memory is handled in a 
slightly si range way, in that each of 
the first twenty-six variables, A to Z, 
may be referenced in four different 
wwS. Thus A, AS, A( I ) and ASf I > all 
jeter (oihe first variable, B, BS, N?) 
to the second, and so on. The use of 
variables is listed in table 1. 

In playing the game, it will be 
found helpful if a seven-by-scven 
grid is drawn, and the inhabitant of 
each cave marked as it is visited, in 
case it is wished to return to, or 
avoid, a particular cave. It is quite 
dilYicull to complete ihe quesl in 40 
days. Happy hunting. 



Tabks I; memory uttSnatiuti 

ASCII - A$C4) are set up 
befpfe running. £ atid F me used 
by random number y«i«(iiiur 

A$(T> - FAtrVY 

A$12) ^ "TROLL" 

A4I3J = 'GIANT" 

A*Hl ■ 'DRAGON 

E ■ decimal Traction 

F 

G - energy oft player 

H - siranrjih oi advo/sary 

l = working variable 

J$ = intaractrvo response 

K ■ cio-ordinate within mairix 

L - previous response 

M ■ count of days 

A414) - A{*a - matrix 

A<65t - treasure lound indicator. 



The second proKTain by A E Cox 
of Sussex, is a very interesting 
indexing program written for the 
Sharp 1500. h can sort up to 120 
cha racier strings of 79 characters 
each into alphabetical order and then 
prints them out as shown. Could it 
be the first genuine useful word- 
processing program for a pocket - 
sized calculator? 

Each item is printed immediately 
after it is entered, taking up to about 
4.5 lines of print. The items arc then 
sorted oui into alphabetical order — 
ASCII priority — and prinud our 
lengthwise it: blocks of 12 items, 

The user should first check ihat 
ihcrc is adequate pap«r and Text 
mode is Csiie 2. Now press Def A. 
Next, write first item and Ruler. 
Write each subsequent item in the 
same way. To sort, press Del" ft. 
Print-out follows automatically. 

To amend ilems, noic the tally 
number at the end of the item to be 
amended. Press Break. Write L-n 
— tally number and Entry. Press 
Def C. Write the new test and 
Enter, then press Break. Write 
L~tn, where m™l + last tally 
number pn the prim-out . Enter. 

Press Def C: continue. 

Items already em erect may be 
printed out lengthwise without 
sorting, by pressing, Del" D. 



YOUR COMPUTER. APRSL 1983 131 




IMWf 



IN VflUK HIGH 

sriti ii shops 






by ■ 
tor 



Addictive Games 

SPECTRUM 48K 
AND ZX81 1BK 



ACTION 
FROM ' 



xZt 



*/' 






/ 



y. 



version 



^P This superb gam<? is now available from branches. <ji 
W. H.SMITH ami BOOTS THE CHEMIST 

M*nage youi QW ™ te*m in (hvs exciting game of Skill which 
vividly Ciipiur^s the drama and excitement of real Inmhall 



FEA TURES INCLUDE: 
* 4 DlVtSfONS * FA CUP • PflOMOTION 1 RELEGATION * 
» TRANSFER MARKET * TIAM SELECTION * 
* SAVE GAME FACILITY *## AMD MUCH MORE I ** • 



WHAT Tni PR[f $ 5*VT ABOUT IT; — 

* /f rOU tan mtwMtt mnlBcf f c mttnmo* * toatUMB HIM, FOOTS Al L 
MANAGER, hem Adittctt,* G iir^t, hi for you — T/t* ft trt m n »W fer 
* fvottnlt fmnmUc but litw mail mtmemtttng tAuiy for u J nr*l I** J -O 

T'CI.'1'l -' UI-Tf fr. i-ihjI- If... pMAniwtft *» rn,..v rftr y.^m- it .1 nnnf> 

SinCUmh U5mnB«U*»f 1»1J 

» AfViHoupA />> nauitMt /cm) ri»*H f*n. f ,n*ty -r tr , yr< lpi M f"jf Ihn ammr 
— fJtc*ffiMtf m*r» m*tfH3/(i>li)K fgifmif .d»f7rwrf cw#prfcnrr TiSo jumc 
it *** r Mi>Ff *#y pv f tOC*fr>wt, la rrwl «Ai> drvrlapmrnt at iltiftpy *n,t 

Ifl* *Vwirf^ f*if*rtf tf * rAr # 4 C«p wA^f r il w# i DHlfA Etr* xrcrsMtrt 
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tHrtirf WMtrti outl 



MitlfrWnp.1 ILbkmwI 
*i|lirK.CCi-Wi»TJTWr»i IHb% T kmt> 

ThI CGtmwltm ■ 

P"tOI| Pf II KlVMI 

a*vb tittr* m g-im» cum purr* emi?*i 



ix com ru him a* ib march imj 



»|?5«iil>HllE101lLTI« iFi-t.u- >m«t 

TpOid«p t«nd Chtw>f P pa*al>l« ta 
i»»fuy| r;j.«ft Ci-ri 4 IDU.iN 



COMPUTACLUB - UK 

Why not join ComputaClub UK and have a Software 
Library at your fingertips? Members can receive programs 
for up to half-price, YES, HALF-PRICE! 

Most machines are catered for and ALL our software is 
guaranteed. But we don't just deal in games programs 
either. We have a comprehensive calalogue for you 10 
browse through at your leisure. 

So fill in the form below for a 6 months TRIAL 
MEMBERSHIP and accept a FREE games cassette {worth 
over flO. 00) as our special opening offer to you the 
customer. 



6 MONTH TRIAL MEMBERSHIP 

To COMPUTACLUe-UK, 
Commercial Works. Church Accrington. Lancashire. 



Oate 



Please accept me as a member of your club, and send me my 
FREE gamos cassette- I enclose my fee of 0,00 made payable to 
"CompgiaClubUK". 

My Computer is Storage Capacity.., 

My Name is {please use BLOCK CAPITALS! 

My Address is ....*,......«.«........,.... 



Signed .. 



Ht*lilMM»1Hlllbl>l1t4 Tel* tiitl 

........... Age Cif under IB}. 



^DRflFT 

■ ■ ■ ■ 

Cafa Review, Analysis & Formutetfon Technique 
Makes the 16K-ZX81 a serious data processing tool 

'* . , probably thebett spreadsheet program av&tfabte tot the 

ZX81." 

"'. . . turns the ZXSt into * serious toot for recording and 

analysing data st home. " 

"Thoughtfully writ tun and very «*tv to if if - yet mora compre- 
hensive ths/i many programs written tor forger computers end 
which take days to master. " 

jjjg Spreadsheet flexible from 5 to 80 columns wide with up \o 
450 "grid position*" 

■:m - Comprehensive report generator and full text/data listing 
facilities are usable at any stage — all with instant machine 
code speed 

gg Columns are displayed 3 at a time In arty order you wish — 
vastly superior to the clumsy "window" system 

■J Range of 21 calculating functions: Arithmetic, Average, 
Percentage. Group Total, £0.00 justification and all the 
keyboard fcientif ic and trjgonomerr lc functions 

M AH reports and listings duplicated on the ZX primer as 

continuous copy 
ffi Named MDRATT file* can be "saved' either full or empty 

but ttruciured lor repetitive later uje 

S| Detailed instruction manual covert all facer* of the program 




4 

Send now (a 

idon Software, 
Sox 2, Tadworth ^ 
Surrey KT20 7LU 



Pfeasa tend me . r r»T;T=uii program(i) 

I enclose a chequa/p. order for £ 

Mama , 



Address 



A jJ 



132 VOUfl COMPUTER. APRIL 1983 



SOFTWARE FILE 



Software File gives you the opportunity to have your pro-ams, 
ideas and discoveries published. We will accept contributions for 
any home computer provided they are submitted to Your Computer 
exclusively. Please double-check your programs and specify the 
memory they require before sending them, preferably on cassette. 
We pay beiween £6 and £36 for contributions published. 













36 00 01 


Figvr$ J, 










OC 08 C9 


Address 


Hexadactmai 


Figuri 


i 2. 


165U 


2A 


0E 


40 


1 


Rem [75 Xs] 




06 


11 


36 


10 


Let A$="" 




OS 


0b 


21 


20 


For X = 16514 To 165BB 


16523 


2b 


0D 


20 


30 


If A$=""Then hput A| 




FC 
ID 
}6 


5E 
20 
OS 


1C 
22 
0E 


40 
50 


Poke X,16x Code A$+ Code A${2)-476 
Scroll 


16535 


21 


23 


0D 


60 


Print */'( 3 spaces)"; AS (To 2) 




20 


FC 


36 


70 


Let A$=A$(3To] 




00 


0E 


21 


B0 


NextX 


16544 


2B 


0D 


20 


Figure 3. 




FC 


0E 


FE 


1 


Rem [machine code] 




OU 


20 


FD 


5 


Let score=0 


1655 3 


Oh 


Kb 


0D 


10 


Print At 4, 6; "boh" 




20 


hU 


10 


20 


Let A=10 




D7 
01 


do 
00 


00 
00 


30 


Let L = 


16565 


C9 


26 


2B 


40 


Let A-A+(lnkey$="8"And A<291- 




28 


0E 


05 




(lnkey£="5"And A>2} 




23 


36 


00 


50 


Print At 19 l A-2 ; "pQiiD" ; Atie j A; 


16574 


0D 


20 


FA 


60 


ff lnkey$ = 't)" Then Let L=Usr 16514 




0E 


1F 


23 


70 


If L<> Then Let score=score+1 




00 


20 


FC 


80 


Goto 30 



Search and destroy 



C Stewart^ 
South Shields, 
Tyne and Wear. 



2**a? 



This short machine-code routine produces a 
missile on line 18 on the display. Ji proceeds 
upwards searching for an alien as ii goes. The 
missile leaves ihe display if no obstruction is 
ibund, or blots it out if an obstruction is found. 
The machine code is stored in a Rem in line 1 
containing 75 bvtes. After entering: 

1 REM 175 Xs) 
finer the hex loader in figure 2. Run. the 
program in the fast mode and enter the codes 
given in figure 1. They can be entered 
individually — 2A Newline OE New-line — or 
in batches of as many as you like — 2A OE 40 
06 Newline. To operate the routine the print 
position mosi be set to; 

PRINT At 18. A; 
immediately before calling the routine, where A 
is the column you wish the missile to appear in. 
To increase speed, Poke 16549 1 — less than 255 
— and for rhc missile character, Poke 16520 — 
code character — and Poke 16533 — code 
character. 

[nptiv the program in figure 3, which 
demonstrates the routine. Run the program 
and move using the 5 and Stays. Try missing 
the alien and then hitting it. Line 70 keeps the 
score and line 30 must be within the main loop. 
Lme on the display is leir untouched by the 
missile for scores and titles, however more can 
be left by Poke 165 IS, The routine is ideal for 
invader -type games. 



Space chase 



Tshir Abbas, 
Edinburgh. 



&m:>M\ 



In THJS GAME for the 48K Spectrum, you 
shoot down 10 alien craft before they reach (he 
talc zone. You ait looking out of your cockpit 
window and have to line them up in your sights 
and fire your lasers. If they reach the safe zone 
then you have failed. The bottom of the screen 
displays time left and craft shot down. 
To fly your ship use these keys: 



Up 


7 


Down 


6 


Left 


5 


Right 


8 


Fire 


O 



This program uses three machine-code 
routines. The first of these copies the screen 
into Mother pan of the memory. It acts a* j 
kind of CLS but it recalls the saved screen 
only T clearing everything else on the screen. 



Space Cbase program construction. 

IB TO 19S SCREEN CONSTRUCT IOH . 


19B6 TD 99S9--ENO Or 0*tHE 

ROUTINE A DRTTR. 


seo 


TO 2Q2--LORO CJRTR I»OR SOUNt 
AND SCREEN BOUTINES . 


Space Chase graphics. 


3BB 


TO 305--V/RRIRDLCS. 


»Wt fleCD LINES 50S A GOS 


5»8 


TO 5&8--PR1HT ALIEN CR«FT 
A MOUCHtNT OF VQUR 
CRAFT. 


:*-- — e. cmr* us 


6 as 


TO 70S— FIRE LASER. 


• **. UNC 96S 


see 


TO SSfl- -EXPLOSION A SOUNDS. 




CMH 


to «BO--r*RrKT aTfm*. 


• G. LING «©7 



Repiiter HI- holds the location where the 
copy starts. Register HI*. hnki\ location where 
screen is moved to. Register BC holds the 
amount of bytes to be transferred. I-Pir carries 
out the task of moving the block of memory. 

The next machine-code routine enhances the 
Spectrum's sounds. It uses the Spectrum's 
sound routine in the ROM. Register DE holds 
duration of the note; register HL holds pitch of 
the note: and register B controls the loop. 

The final machine-code routine prints out the 



explosion. The data for the explosion is held in 
location 40051 onwards. All the machine-code 
routines are held in Data statements wichifythe 
program. So there is no need to toad them 
separately in the Spectrum, The sound routine 
used in this program was developed from the 
sound routine printed in November's Your 
CwHfHtttr. 

Once you have mastered the game as it 
stands, you can make il more difficult by 
reducing the time variable "if in line WO. 



1 REM *#***SPRCE ChftSEt**** 

2 REM WRITTEN BY TflHIR RBBR&. 

3 REM FOR THE 

*SK SPECTRUM, 
5 REM SCREEN CONSTRUCTION. 

10 REM 

11 INVERSE 0: OVER 0: BRIGHT 
: BORDER 3. PRPER 0: INK 9: CL.S 

20 INK 6: PLOT 112^4: DRAW 0, 
15, -PI: DRRU 15,0: DRRU 0,15: l>R 
RU 1,0: DRRU 0,-15: DRRU 15,0: E> 
RRU a,-15,-PI: DRRU -15,0 

30 DRRU 0,-15: DRRU -1,0: DRRU 
, 15; DRRU -15, 
£0 PLOT 105,92: DRRU -15,0. DR 
RU 0,-1: DRRU 15,0: PLOT 151,92: 
DRRU 15,0: &&&U 0,-1: DRRU -IS, 




50 INK 7 

70 PLOT 30,0: DRRU 15,15; DRRW 
1,0: DRRU 5,5: DRRU 1,0: DRRU - 
S , -O : DRRU 1 , 

80 DRRU -5,-5: DRRU 20,-10 
90 PLOT 225,0: DRRU -15,15: DR 
RU -1,8: DRRU -5,5: DRRU -1,0: D 
RRU 5,-5: DRRU -1,0: DRRU 5,-5 
100 DRRU -20,-10 

105 REM 

106 REM COPY SCREEN 

110 FOR f =4.0000 TO 40050: RERD 
a : POKE f,3: NEXT f 

120 DRTR 33,0 , 64, 17,60, 195, 1, 19 
2,26,237, 176,201,33^80, 195, 17,0, 
64-, 1, 192,25,237,176,201,0,0, 17, 1 
0,0,33, 10,0,6, 10, 197,213,229,205 

{continued an page 1351 



YOUR COMPUTER, APRIL 1963 133 



NEW SPECTRUM AND 
ZX81 SOFTWARE 

"WINGED AVENGER" 

Fa* and hjroui SPECYftUU<<wv0nhu5OUMD*ftd USER GRAPHICS 7 LEVELS 
3 WAVES. MOTHER SHIP HIGH SCORE. flE FUELLING. RAPiO FIRE. SMART 
BOMBS ind LASER SHIELO PCW "ONE OF THE BEST SINCLAIR GAMES VET 
Ortfy C4 50 AH SPECTRUM ♦ 16*2X01 

"SPECTRUM SCRAMBLE" 

MORE M CODE ARCADE ACTION SO GOOO THE REVIEWERS OlONT ftEAChr 
THE FINAL STAGE INOT BAD EHH| HO LESS THAN 6 OtRECTONAL KE VS tef i 
SMOOTH MOVE F»* AflCAOf ri*t u r« iMMftt, LASEH5. BOMBS. iWSTANT 
RESPONSE, CONTINUOUS SCOfllNQ. ROCKETS. SOJNO. PuEL PUMPS. HEO 
METEORS. DEFENDER CRAFT *na HIGH SCORE 8«w*« CONCH TlON RED W«i 
tt» cm* yev MOVE FIRE imi BOMB AT THE SAME TIME RELEASE PRCE a* 
M*4 16*0* *8K SPECTRUM 

■DO NOT PASS GO" 
NOW THE 46K SPECTRUM VERSION IS READ V 

A COMF1 F f F SIMULATION at m« BE ST SEl L ING BOARO GAME , you Uno* PA R K 
LAME Hid •» efurt Op lo SIX PLAYERS w compw* **ti the MICRO tang a! I*« 
WORK Acs •» DICE THROWER. BOARD. RENT COLLECTOR. UMPIRE. BANK. 
RULE BOOK. ACCOUNTANT and PROPERTY RECORD SUPER GRAPHICS by 
Guy Konn*oY |tt*nks mat*. GAME SAVE won «nrmm k 1»f feporl COMPLETE witn 
INSTRUCTION BOOKLET The ULTIMATE 1*1 FAMILY GAMES Oftft i MONOPOLISE 
VOUR MICRO AMAZE Ml your trwniJi Hid famriy (Can you •» your GRANNY on ■ 
MICROS ONLY CS*S 1 W. ZWl VERSION ALSO «,M. 

"BASE INVADERS" 

Th* ONLY ARCADE G-*E EtficrtrtJUOT SmOljLU HAVE Th* SCREENS ID* 
Mime. THE INVADERS vt llw sums. BUT you g*1 a SHIELD aDd a CHOICE ol 
THREE SPEEDS |OK , FAST or (NCREDfBLE) GOOO SOUNO, 4 HARD GAME. 
and GREAT GRAPHICS . COUPLE TE yav io*wiub caMacbon lor (usl C4 SO t«K and 
*B«9PtCTRUiyi(yiN. 

"AUDIO SONICS" 

WINNER el WlZZ KID tS For ma SPECTRUM AS <««•» k*m* attaetl tor your own 
{TOOtim* M PRE SELECrrO SOUND EFFECTS *<**!* TELEPHONE. POLICE 
SIREN. FROG. SPACE EFFECTS and OUTBOARD MOTOR GO mw MODIFY and 
yom *rs pdnantarj «n a display ol SLIDER CONTROLS lo arAuH PITCH. RISE. FALL , 
BHlSKNfSS. OECfL. ACCEL L. TONE. REPEAT RATE. STUTTER VK) DELAY 
ADJUST Bw SLIDERS Itwi INSTANTLY h**r ma SOUND CREATED. Call "THE 
SOUND ONE" and a program toa mil appsitr inn >t raaoY tor *iaarth>i mlq your own 
prDorarm. Hound! EXPLORATION. YOU WILL BE AMAZED what BEEP Can DO. Wa 
ara proud fc) othw lri* t1 U 99 IftK or 4flK SPECTRUM 

"SPECTRUM RENUMBER DELETE" __ 

AH MCQOF. Rt NUMBERS All NOT PART "YOU WONT BUY A BETTER* 
RENUMBER PROGRAM FOR THE SPECTRUM- JUST 600 BYTES Al £4 95, ALSO 
ZX*I VERSION 

"HIGH NOON" 

Wrt*n YOU VE SAVED In* GALAXY. SCRAMBLED or wttat*v*f tH* yftu do on your 
MICRO, whal about * GUNFIOHT? Play |ha SPECTRUM <V YOUR PALS THREE 
LEVELS FULL FEATURES. CACTI, COFFINS. WAGONS. RAPID or SINGLE 
SHOTS SUPERB GRAPHICS OOO0 SOUND mdudrngi DEATH MARCH ESCAP 
ISM an TAPE for JUST H. 50 

'DISPLAY" 
Taftn ovar MrfMKi BJN and tn* DEMO lac* NMtoD How would you i*w i T3 diHatant w 
datM-wd LiHAi'MlCSiTi a l« SPECTRUM EM »GFW*D13fl Its* a 4fl*L All ol rhot* can 
bv **pi*ywJ on I ha ktho ad trw SAME TIME UK* ai« ttoi*d t* PAGES end any 
TWO PAGES may pa aicntnoM m momory FILES can ba LOADED FROM or 
SAVED TO TAPE LOAD nio any oaga iccaloo. TURN a UOG '/• mm >fl i\jtr>. FLIP a 
SHAPE fcinr HE VERSE a SHAPE. EXPAND M Ol i CHARACTER into a luN 
character UP. DOWN. LEFT or RIGHT by on* PIXEL. 5 SHAPE FILES art included oq 
TARt INCLUDING a 64 CHARACTERS par LINE DISPLAY COMPl ETE with DEMO 
PROGRAM and INSTRUCTIONS JUST Ht LEASED at E7 00. 48K or ifiK SPEC- 
TRUM Dray 

"YAHTZI" 
Up lo SIX playari aKowfld. PUyr thacLiSsk DICE (j»m»of >l'*!njy. fiM alartn* icorepod 
eomDhrra «nrK GAfrRY'S "CHUNKY LOOK" tftaracler aal. AH cheating aitd arrow 
rS|04t*d by your etotronfe un^wc Upd»t» ynur o«rn«* .cupboard 'o» ft 50 +8K DULY. 

"MATCALC" 

For BUSINESS and PROFESSIONAL us* Idaal lor WHAT IF xtualiona. CASH FLOW 
FOREC STS and analysing RELATED frQvrat 94 (harao** display 00!*" FORMU- 
LA may ba MATHEMATICAL or LOGICAL MENU flf FUNCTIONS SAVE and LOAD 
DATAwTAPE F ULL malruct-oni «K>vdad LITERAll YHUNDRED$ o! OSES BOTH 
4*K and I6K SPECTRUM PROGRAMS on ONE TAPE. JUST (7.00. EXCELLENT 
VALUE 

PROGRAMMERS DREAM 
A SPECTRUM TOOLKIT PovkHi inoopnndanl and rust 1450 BYTES Fac*ti*a 
RENUMBER l.i»i or blocMi any ny ramam or iltn BLOCK OR LINE MOVE rtdudmg' 
a RENUMBER «lp place il req^red BLOCK OR LINE ERASE CHANGE SELECTED, 
STRING S INAMLS OR CONTENTS) DUMP vanatlc names and valuta imiM in a 
K»p|. DISPLAY PROGRAM w PROGRAM pAn VARIABLE S42E INSTANT and 
CLEAN JUST CG S4 wfth dipk&l siitruflOnj 



WORK FORCE 

140 WILSOEN AVENUE. LUTON, BEDS, ENGLAND 

ALSO AVAILABLE AT BUFFER. MlCftOWAn'E AND SOFTWAHE SUPERMARKET 
REM WORK FORCE WORKS HARDER. 



"\ 



HILTON COMPUTER 
SERVICES LIMITED 



The renowned PERSONAL BANKING 

SYSTEM is now available for 

ZX81 C ZX SPECTRUM □ DRAGON 32 

Maintain permanent recores and fully detailed statements 
of your finances including: 

• ALL cheque book transactions and bank receipts. 

• ALL standing order payments. 
AUTOMATICALLY PROCESSED (monthly, quarterly, 
six-mqnthly or annually AND for set number of 
payments}. 

In addition the ability to search, locate, delete or correct 
previous entries. List by category facility is included. 
Additional BANK RECONCILIATION module available to 
automatically match your Sank Statement to your 
PERSONAL BANKING SYSTEM account. 
Full instructions and GUARANTEED after sales 
maintenance provided, 
PBS ZXS1 E895 (16K) . ZX SPECTRUM £9.96 |48K) 

DRAGON £9.95 (32K) 
REC (for use with above) £5 00 
Ask for the P8S at your local computer store, or 
ORDER {specifying for which machine) by POST 
from 

Hilton Computer Services Limited Dept (yo 

14 Avalon Road, Orpington, Kent BR6 9AX, OR al the 

POST OFFICE using TRANSCASH ACCOUNT 302 9557 

• YOUR PBS fS NEVER OUT OF DATE * 






games 

for your Spectrum 




Sorcerer's Castle £5.50 



New from Mikr-o-G#n -takes you mio a world of magic and mystery. 

Gra&htcal poattloo and a host of options with this exerting advwntur* 
game for (he 4&K S peciaim 



Scramble £5.50 



High-speed arcaoe game - ihe fastest available Tirusl attitude. Bre 
and borrrt>coo|rol». Fof 1SK or d8K Spoct rum 

Masterchess £6.95 

The program tor the ml player - a powerfu I. adventurous and 
enjoy abl a chess game for trie 4S K S pec! m m 

And for your ZX81: 

Scfarnoie -t- Frog* + Paintmaie + ZX Chess + Breakoui + Space 
Invaders + Asteroids + Tempest + i KGamespack + Oebug 
ui mn*t iiawiii hi bwtwi - 1) to (B Cm IS SOi 



;-Ti.»t»Ot[ilrtS*Wll**04rHM »«. *S# not-" 1 Htu^ 



M^iD^i 



24 Agar Crescent Brae kneti Berks RGi 2 2BK 



134 YOUB COMPUTER. APRIL t983 






software me. 



(continued from page 133) 

,,130 PRINT INK 4; flTT 21 , 10; "TIhE = 



140 
6,0: 
<3,9 
195 
19G 
197 
186 

see 
o 7 



PLOT 75,0; DRRU 
DRRU 0,-9: PLOT 

DRflU -18,fl 



0,9: DRRU 7 
170,8: DRRU 



FOR t mm 
CHR* g 4-f , 



T 



READ 



LET t=U5R 40800 
RESTORE 3600 
REM 

REM USR GRAPHICS 
FOR 3=144 TO 150 
READ d ■ POKE USR 
-■ NEXT f ■ NEXT 9 

202 FOR f -4-0051 TO 40169 
a : POKE fji: NEXT f 

310 POKE 40027,10: POKE 40033,1 
0: POKE 40041,100 

230 ITT (. =USR 40012. PRUSE 30 
300 LET t 1=500; LET Sh=10 
305 LET x^iNT fRNDflS) : LET y=I 
NT (RND*a7) 

310 GO SUB 500 
330 GO TO 900 
500 PRINT RT " . -j ; " Mtfrl " 
505 PRINT RT 21,15,ti: LET U^t 
l-l 

510 LET X-X+INT (RND*3J -1 + dNKE 
Y(="7"J-(INKEY*s"6") 

520 LET x=x+2* t «x <0) - Cx >16» ) 

vl^5-fI t iNK^XI"e^ D " 33 - 1 + <1NKE 

540 LET y =y +2* C <y <0> - (y >2©) J 

550 LET LsUSR 40«1P 

550 RETURN 

600 REM 

605 PRINT RT X , y . " »4tM " 

610 INK 3: PLOT 54,22: DRRU 72, 
67: PLOT 301,22: DRRU -72,67: LE 
T I =U5R 40026: INK 7 

6£?0 ir POINT (123,901=1 THEN GO 

TO ©00 

660 GO SUB 500 

700 RETURN 

300 REM 

301 LET L=USR 4.0012 
303 PRINT RT 21,15, U 
604 POKE 40027,5: POKE 4-0033,20 



POKE 4004 1,30 



LET t =USR 
NEXT r 



400 



505 FOR f-i. TO 2: 
26: POKE 40053,60: 

606 PRINT RT 0,0; 

810 POKE 40027,1: POKE 40033,1; 

POKE 40041,0. POKE 40159,0 

615 POKE 40150, INT (RNDtS) tl46 

820 PRINT : LET LsUSR 40135 

S25 POKE 40150,32 

330 POKE 40027,1; POKE 40033,1: 

POKE 40041,0: POKE 40159.12 

332 PRINT : LET L-USR 40135 

334 LET LsU5R 400X2 

635 POKE 40027,10: POKE 40033,5 
. POKE 4004 1,250: FOR f=l TO 10- 

LET L=USR 40026: NEXT f 

345 POKE 40027,10; POKE 40033,1 
0: POKE 4004 1,100 

650 LET Sh=Sh-l: PRINT RT 21,20 
JSti: IF Sh=0 THEN GO TO 2400 

360 FOR F=l TO 20; NEXT F GO T 
O 305 

905 LET V=TNT (RND14) +1 

910 IF ti C23 THEN GO TO 1000 

920 RESTORE 7080+V 

930 LET ajj=", - 

940 FOR f=l TO 6 

950 GO SUB 500 

960 RERD j , k 

965 IF j<8 OR j>11 THEN LET d$= 

hd _ ii 

967 IF j<4- OR j>15 THEN LET J * = 

970 PRINT BRIGHT 1 , RTT i,t;at 

975 IF INKEYf="0" THEN GO SUB 6 
00 

930 NEXT F 



LET 9^65 



LET 11= 



990 GO TO 905 
1000 LET Z=B5: 
85: LET L2=S 
1010 PLOT Z,9: DRRU 11,0: DRRU 
,12: DRRU -tl,0: DRRU 0,-12 
1020 GO SUB S00 

1030 LET 2^Z-5: LET 9 =g -5 : LET L 
1=11+10: LET 12=12+10: IF 1=0 TH 
EN GO TO 2000 
1050 GO TO 1010 

2000 POKE 40027,10: POKE 40833 , 1 
0: POKE 40041,100: LET L =USR 400 
12: FOR r=l TO 20: LET L =USR 400 
26: NEXT h FOR f=l TO 100: NEXT 

f : CLS 
2005 LET TI=0 

2010 BORDER 2; PRPER 3: INK 9: C 
LS : PRINT ; PRINT : PRINT "YOU 
HRUE FAILED IN YOUR MISSION 



sh 



FE 



!. , 



ENEMY CRAFTS PERCHED THE SR 

"ZONE. " 
2015 GO SUB 2700 
2020 INPUT "DO YOU WISH TO PLRY 

rgrin *? cy^n) *'; ft* 
2030 IF a*="y" OR a*. = "Y" THEN BO 
RDER 3: PRPER 0: INK 9; CLS PA 
USE 50: RUN 205 

2040 PRINT ' ' "THRNK YOU FDR PLRfY 
ING.": STOP 

2410 POKE 40027,5: POKE 40033,20 
POKE 4004 1,200: LET L=USR 4 001 
2 

2420 FOR F=l TO 5: LET L =U5R 400 
26 : NEXT F 
2500 PRUSE 100: INK 1: BORDER 4: 

PRPER 6: CLS : PRINT RT 0,0; "UE 
LL DONE" ''"YOU HRUE COMPLETED YO 
UR MISSION SUCCESSFULLY." 
2510 PRINT ' ' "ALL 10 ENEMY CRRFT 

ARE DESTROYED" 
2520 GO SUB 2700 
2600 GO TO 2020 

2700 PRINT ' "YOUR SCORE IS ";TI 
*10+ ( C10-SHJ *10) ; RETURN 

7001 DflTR 10,15,9,14,8,13,7,11,4 
,6,0,0 

7002 DRTR 10, 16,9, 17,3, 13,7,20,4 
25 31 

7003 DRTR 10, 15, 11, 14, 12, 13, 13, 1 
1, 16, 6,21.0 

7004 DRTR 18,16,11,17,12,18,13,2 
0,16,25,21,31 

3600 DRTR , 24 , 60 , 63 , 63 , 63 , 60 , 24 
,17,35,71, 141,255,255, 127,9, 136, 
196 ,226, 177,255,255,254, 144,0,24 
, 60 , 252 , 252 , 252 , 60 , 24 

3620 DRTR 0,BIN 10000000 , , B IN 
0000010, , BIN 1*1000000, 0,BIN 000 
01000 

3630 DRTR 0,0,56,124,124,124,55, 
0,60, 126,255,255,255,255, 126,60 
9000 DRTR 10,15,10,16,8,17,12,14 
, 12, 17,6, 14, 12, 13,8, 13,8, 13, 12 , 1 
3,9,12,11,19,11,12,9,19,7, 13, 13, 
IS , 7 , 13 , 13 , 13 , 13 , 12 , 7 , 19 , 13 , 19 , 7 
, 12,5, 14, 14, 17,6, 17,14, 14,12,11, 
8 ,20 

9010 DRTR 3, 11,12,20, 14, 15,6, 18, 
14, 16,6, 15,9,21, 11, 10, 11,21,9, 10 
,10,22, 10,9, IS, 16,5, 16 
9020 DRTR 33,115,156,6,42,62,22, 
215 , 126 , 215 , 35 , 126 , 215 , 35 , 62 , 32 , 
215, 197,2P9,205,90, 156,33,232,4, 
43, 124, 181,32,251 ,225, 193, 16,227 
, 201 



Screen copy. 

40000 i_f> 

40003 |_t> 

40006 l_[> 

40009 LOIR 

40011 RET 

413812 UI> 

48315 t_I> 

400 IS i_D 

40021 LDIR 

40023 RET 



HL, 1638* 
DE , 50000 

IC6335 



HL , 50OCK? 
BE , 163S4 
6C,6335 



Sound enhance* 


4082ft 


LD 


AOBsg 


LD 


40032 


LD 


40034 


PU&H 


+ 0035 


PUSH 


40031 


PUSH 


+ 0037 


COLL 


40040 


LD 


40843 


POP 


40044 


PDC 


40046 


F'Oi > 


40047 


POP 


4 0048 


»JHZ 


40058 


RRT 



Ht_ , 10 

B,&0 

BC 

DC 

HL 

BC , S00 

HL 

HL,BC 

OE 

BC 

40034 



Dream machine 



Tim Cotdingham, 

Maidenhead, 

Berkshire. 



soaaaa 



M0S1 ADVENTURE game* invoke a series of 
choices among a finite number of situations. 
Here is a program Thai gives a completely free 
rem \v your imagination, h is written for the 
Dragon, but could be readily adapted for other 
machines. 



The scenario is that the computer has been 
plugged in to your unconscious mind, and it! 
RAM now contains details of the dream you 
dreamed last night, which you yourself have 
now forgotten. You have to reconstruct ihe 
dream by a scries of yes or no questions. The 
resultant dialogue can be both hilarious and 
revealing. 

It is strongly recommended that you run the 
program a tew times without attempting to 
understand how it works; if possible, have a 
friend key it in for you. 



The program is based on s party game, in 
which one of the players who does not know 
the rules is sent out of the room. The other 
players ostensibly concoct a dream; but in fact 
the simple rule is thai they answer "Yes" to any 
question ending in a vowel, while questions 
ending in a consonant get a "No" response. Y 
is treated as ambivalent. 

This simple algorithm has some limitations. 

In practice, very few words end in vowels other 

than "e"; and the game is inclined to get stuck 

'continued on page 1 3 ?> 



YOUR COMPUTER. APRIL 1983 135 



ZX SPECTRUM 



GHOST'S 
REVENGE 



At last a maze-chaser game for the Spectrum that rivals 
the arcade original. Written in super fast machine code and 
featuring some of the best graphics, colours and sounds 
for the spectrum, 

•Joystick or keyboard operation • Realistic gobble action in 
afl 4 directions • Four intelligent ghosts that wilt chase or 
run from you * Pulsating power pills that change the 
ghosts' colours * Eat the running ghosts for 400, 800, 
1,200, 1,600 bonus pts, • Skill level selection enables both 
beginners and experts to play • Harder levels feature 
invisible mazes • Full solid effects times and top score. 

DESPATCHED BY 1ST CLASS RETURN POST 




ONLY £5,95 



INCLUDING 1ST CLASS 
POST & PACKING 



vCi 



Post coupon now to; MICROMANIA SOFTWARE 
14 Lower Hill Rd, Epsdm. Surrey KT1A 8LT. 

Please rush me 

Q copies of GHOSTS REVENGE at C&.95 

I enclose Cheque /PO/ cash for E 

Sorry no credit cards. 

Name - 



Address 




Cassette-Based Business Software by Andrew Crane 

for 

EPSON HX-21 PORTABLE 

NEW from MST CONSUL TANTS 

STOCK CONTROL PACKAGE 

£25.00 fully inclusive 

You will wonder how you ever nonaged wurioui iNs simpie-io-operato, 

'.i'H . ontsin-utt, functus.' ^ I, bt&ck-Lomrol *Y*imn Fcaiures Midutla 
'H^fd copy on intfyrfll printer 

"Ruady access to all slock records 
* Daic and lime Tf-.ordirifls of trfinte« listings 
'Ab-iity id store! thousands of stock itums on mtc.tQcv&miv fii« 
'Mwiu based opuons rlisplavitJ on rnti*gfai LCD screen Software Menu 
Options inrliuli' 
Add,- Amend slock, slock search, rfeteie Stock, rporrter n>pwi, stock 
evaluation, srocfc liiT. amend sttKk levels, Ni' vjmhangr 
Also EPSON HX X DATABASE- SUPER CAPACITY card indw sysi«m 
ChOOS* yotir own hearting* , FftciMwJ* mclurh* sorts, «safrhf»i, ftpkl lolal* 

ate. £25 inclusive. 

DRAGON 32 PACKAGES - available NOW 

MST DATA BASE - Cord Index filing system, f 14.95 inclusive 

MST INVOICES and STATEMENTS - Prints excellent ar>d 

detailed documents, etc, £14,95 inclusive, 

MST STOCK CONTROL — Stock lists, stock evaluation, 

Reorder reports, etc, f 14,95 inclusive 

MST BUSINESS ACCOUNTS -■ Debtor/ Creditor details and 

summaries, etc. on printout. £14 96 inclusive. 

MST MAILER — Dedicated database for formatted address 

labels fttc. £14.95 inclusive. 

Each program comes with dose risji i v« leaflet. uu*rator notes, etc. Each 

customer will receive o*1*il?of our hol-kn* linV. ChpqutJs^nri Postal QrdCfS 

should bo made payable io MST Consultants, Rilly-incluHv« [W'&es include 

VAT and postage costs, 

TRADE INQUIRIES WELCOMF 

Send your remittance or Access card no. & signature to: 

MST CONSULTANTS 

Newton Road, Bovey Tracey, 

Newton Abbot, South Devon TO.13 9BB 

Tel: 0625-832617 



E9 



sS. 



COLLEGE OF SPECTRUM 
ZX81 USERS 

(BBC users very soon!) 

This is to certify that 

SCISOFT 

Educational nutctial ii an aid to 

passing 'O* L*veli/CSE, 

The following packages arc higJily recommended. 

STUDY PACKS (Include a comprehensive book of notes) 

Physics "O" Level £7.50 

Oiemisiry "O'VCSE Level O.J0 

Biology "O" Lc*el £?,50 

MaThs 1 "O" Level 6.00 I II ordered 

Mnihs IJ "O" Level i6,O0f io*tr,h« ts.oa 

Computer Studies "0'VCSE £6,00 

Teachers Mark book £6(ZX8l) £10 (Sp«[riim| 

JUNIOR SCHOOL 

Jungle Mains ( + — x — ) IS AU for 

A Mroinai hi (■*, Decimals. Fractions) £5 BBC 
Matje Spell (Spellinsl £5 
Mmic* I. II, III £5 =«ch 
Communicant" (Morse. Semaphore rie) £5 

Plraie add 50p for Poitaje and PaiJnng 
5 MINSTER GDNS. NfcWTMORPi:, EASTWOOD, .NOTTS, 




136 YOUR COMPUTER, APRIL 1933 



(cQ/iTiftued ftoni page 1 35) 
if the questioner ends most of his questions 
with "me" The computer program overcomes 
these limitations by selecting five letters ai 
random at she beginning of each run. If a 
question ends in any of the selected letters, it is 
piven One of a choice of affirmative answers, 
picked at random. Similarly, a further three 
letters are selected u-hich produce * 'maybe" 
answers. Even when you know the rule* you 
will still find the same addictive, because you 
do not know what choice of letters has been 
made ftw the currant run. 

To increase the variety of responses, 
questions beginning "Had l"\ "Did 1" arc 
answered "Yes, you had" or "No, you didn't"; 
\nmetnnes the remainder of the question is 
repeated, sometimes not. 

Looking in the program in more detail, lines 
80 to 150 produce a suitably scientific- looking 



SOFTWARE FILE 



"brain scan": any similar graphics pattern 
could be substituted, or this section omitted. 

As there are some letters u-hich very rarely 
end a word, line 2GQ lists those from which the 
selection will he made. Lines 210 to 280 then 
sci up two variables. CS and DS, containing 
respectively live and three letters. The Instr 
function is used to ensure that no letter is 
selected twice. Any question ending in a letter 
thai appears in CS will receive a "yes" answer, 
while the three letters in DS will produce a 
"maybe". 

The question is read at line ?U0, and stripped 
of its question mark by line 140, Also, line 360 
removes a final *V\ so that a succession or 
plurals does not produce the same answer. The 
LiM letter ol the question is then compared with 
CS and DS, by lines iSO and 190. 

Responses are selected at random from the 
appropriate set, Lines 600-630 and 710-710 



transpose pronouns and auxiliary verbs. Notice 
line 760, which presents the question "Was I 
with my aunt?" from receiving the answer 
"Yes, you were with my aunt". 

To introduce some variety, questions are 
counted by line 330, and the first "No" answer 
after 25 questions prompts the possibly mis- 
lead ing response '* Haven't you forgotten some- 
thing'" 

If you want I recap. ,ir. asterisk will pirn! all 
the questions that received the answer "yes" — 
lines 810-850. Finally, if you must cheat, a hash 
sign will show you which letters are currently 
oeing used to make the selection — tine 520. 

You can experiment with variations of the 
program by altering the letters from which the 
selection is made — line 200; by adding extra 
responses; or by altering the probability of any 
particular one being selected — lines 420 and 
470. 



= 6 THC «M» pibchtnc 

TO 'COFfHGrtX T r OC^BTM^MI XiVI 

«".» ELSStPfllMT-Tt* EtH>UTC« HILL MJM110* *tW» 'JUIDUSCEDt^ Pi NO. "OLD M LfW TO 
r*C !ILEW5!Qfc til. ftMJ »Ci.<MCaM*.CTri*. ■ 

tis rntHTtPniKT-nesfi t« smser mtt i**n vqu MMtun'. - 

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ft ■PlOOC 4. :ifiF«£EH hdKLl 

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14.0 MIpT 

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OI4K10U9 niw :r. not «**£ or lMifi ¥du hwe to ours?, h hh scries or ves/M 

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t.;* tr HI «NB «<F l«.N *R|nt- V«U COULO EPY ' M*- - 

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" T!* ■ t^»fc«*#« - ph« 

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mi. r-:r.-- : :.:-. -r 

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. f"is?p «:cfc' n . >. . i ; • •■ 



Option 

Peter Lewis, 

Widnes* 

Cheshire. 



yj'j^j*) 



When programming the sound registers on 
the Vic, there are only two ways to cut out the 
sound. The first is to Restore the computer, 
however this also clears the screen. The other 
alternative is to re-Poke all the registers. 

This program introduces a third option. It 
allows the user to control the volume of sound 
by using the function keys. The program is 
called up 60 times a second by using the IRQ 
routine. 

It is initiated by the command 5Y& 67 3 and 
can be switched ofF by restoring the Vic, 



5 1=673 



IS READ B 

20 lffi= 999 THEN EHB 

22 f0KEI,M 

24 1=1+1 

26 GOTO 10 

36 Ijh Th 1 63 > 1 73 > 141 * SB f 03* 1 63* 02 * 1 41 * 21 * S3 .■ 96 > 2 34 

49 BflTfl 32, 184, 02, 32,205,62, 76, 131,234,234,234 

50 BRTfl 165^ 197. 201, 39, 240, 01, 9S, 173,14,144 

66 BflTfl 201, 00 , 20S ,61, 36 , 286 , 14,1 44 , 36 , 234 , £34 

7% BftTR 1 65 , 1 3 7 , 20 1 , 47 , 240 , 1 , 96 , 1 73, 14, 144 

80 DRTR 201 , 15, 26S , 01 , 96.. 238, 1 4 , i 44 , 36 

9& BflTR 999 

100 REM *** SVS6-73 TO STRRT *** 

1 1ST REM *m RESTORE TO ENB *** 



Lawn mower 



Stmigo Sugiura, 

Putney, 

Lontfen, 



Having iaii.li* all your O-levels you could 
only set a job as a lawn mower, but the garden 
is not as calm as it seems. There are explosive 



cricket halls which you must Hot run over and 
rocks which will blow you up if touched. On 
top of this if your oil runs out. you will be 
vaporised. 

When you first run this game you will rv 
greeted by a short instruction. Then you are 
asked to input your speed, level and (he loud- 
ness, Alter this the game starts with a short 
burst oi* music. You must guttle the mower 



around the garden whilst avoiding the cricket 
bjlls and the rocks and gobbling up the oil 
egos, but this is not all. 11 you mow over an area 
already mowed, your oil will decrease but your 
score will stay the same. So the trick is to avoid 
areas that you have mowed, 

All this furious action is accompanied by 

music in the background and a constant update 

(continued on next page/ 



YOUR COMPUTER, APRIL 1983 137 



(continued item previous page/ 
of the score and high seorc. 

II" you want to change the speed, level or 
loudness simply press liscape. This will start 
the program again without clearing the high 
score. 

lines JO to 2SO, main program; tines 290 to 
450, initialising procedure; lines 460 to 490. 



SOFTWARE FOS 



introduction music; lines 500, 510, data for 
introduction music; lines ^20 to 540, delay 
procedure; lines 550 to 650 set up the screen; 
lines 660 to 750, obstacles procedure; lines 740 
to 1W print the oil cans; lines 800 tu 850 print 
the mower; lines S60 to 900 check the colour in 
front of the mower; lines 910 to 9-10 print the 
readouts; line* 950 10 1010, ending procedure; 



Lines 1020 to 1060 go on to next screen 
procedure; lines 1070 to 1090, music at each 
new screen; line 1 1 00, data for the music ai the 
en J of the screen; lines 1 1 10 to 1 180, music 
during the game; lines 1190 to 1190. 
instruct inns. 

When typing the program in leave out line 10 
and ptit it in after Ihe program is running. 



133 If 

! a 

ira 

2i« 

210 

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— flu cm, 



F>1C^..- 

-OOHt.,' 

FIFfFiT:-; rr 







On the grid 

Steprien Vine, 

ftedhttt. 

Surrey. 

This PR^iR.Ui for the Vic-20 plusi a printer 
will create those puzzles in which a set of words 
are hidden in 11 jirid of letters. All you huvc to 
do is to think of the actual word* you want to 
be hidden, cnicr them and the program will 
randomly unenute them (bf someone to Bud. 
Those of you who have no extra memorv will 
have difficulties, h is possible to work the 
program hut with these few changes: lines J10 
f60 should he left out. This is the alpha son 
and is not essential. Also you will have to do 
jwjy with iIil' display and use up the screen 
RAM; do this by: 

POKE &6,32 
POKE 55, 
CLR 

POKE G4&, 32 Iretuml (run/stopiestorel 
Ykt this alter entering and saving the 
program. After that you will not be able to see 
tconurnjedi on pJtgts 14 U 



te tHPUT"SI3£ OF 0RIB"J>!>V DIM0*<W-V> 

£0 IHPUT"HUHB£fl OF HORBS"; H" MHUttHt-lHTtH/S+l ) > OOSUBfiBe 

3© 5£FFHR<fl>-INT<RMBa>*fi> + i 

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4fl FORI -1 TOM 

SO 05<»Fr«<:MVPM-OX 

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50 VD"V«De> 

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138 WEXT 

110 F0RJ-1T0U 

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]Ge ME^Tl OOTO^OH 

500 R-R*l IFR?X*VTHEH130 

210 OOTOeO 

23d P0KE36e78- !3 F>0KF,Me7S,E£9 POKFT35S7?,i*S 

S«« POKE 1 SS, ' UP IT 1«2 > 64 ' P0KE3667©- 

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500 PEM 

320 FORI"! TON- J 

330 IFt4*( 1 304*0 + 1)9010330 

340 I4*-W*< I 5 1-1* < I -i'Uti 1 + 1 > H*( I + i >*H* ' T-l 

35^ «XT 

3«e IFT*.1TH£H310 

37fl TB*-CHft*tlSJ 

300 CM-O0-2*X-2:3X£ CN*-TBf4-Mtrjf!:^TRfi:CN>,Z) 

301 GR*-CPP*<e; TH*«€f#ft*tlSl-Cft»CM*£*X 

392 CE*"TB**MiD4vsTRffCR>,2) (listing continued on page 14tf 



1 39 YOUR COMPUTER, APRIL 1 9B3 




m 



It could mean the end of 
the rubber duck as we know it. 



fat, 



The HX-20 is a portable computer 
with a full size typewriter keyboard, 
> Virtual Screen, printer and mi c ro- 
sette facility actually built in. A 
nputer with a rechargeable power 
e that's large enough for writing 
ograms and manipulating data 
hi ally anywhere, yet small enough to 
orry in a briefcase. 

let the size fool you. The HX-20 is 
r gimmicky toy or an excuse for a calculator, 
sion machine using □ full extended 
:f Microsoft BASIC with 16k RAH 
lly expandable to 32k and 32k ROM 
mdable to 64k, RS-232C and Serial 

Hie ASCII typewriter keyboard and 
raramable keys brings ten separate 
crtions to your fingertips. 
wer to your elbow. 

runs on its own power supply ior 
and can be easily recharged 
t whilst in use, with the ability to 

HX-20 

PORTABLE COMPUTER 




retain its memory in RAM even when 

switched oft. 

Keeping you in the picture. 

The LCD screen is unique - showing any 
20 characters by 4 lines at a time - enabling 
you to carry out word processing or data entry as 
if you are using a large screen. 
Print Out. Built In. 

The 24 column dot matrix impact micro- 
printer offers 42 LPM in a crisp, precise 
5x7 matrix ior perfect hard copies. Every time. 
And you can choose from a wide range of 
peripherals from bar code readers to acoustic 
couplers for total capabiliiy. 
Epson. Reliability through Research. 

You'll find our name on a highly successful 
range of computer printers. So you can be 
assured of the same quality and reliability 
through an extensive research programme 
prior to the launch of any Epson product 

Write or call us for further details and the 
name of your local stockist (because seeing 
really is believing}. 

Yaull find that the HX-20 is the most complete 
portable computer you can buy. It could even 
change the face of bathtime. 

Which is a bad day for ducks. 



Extraordim 
Exceptional quality. 



Personal Software Services 

THE FUTURE MAKERS 

Arcade Style Games for the ZX81 16 K 

and Spectrum 



GHOST HUNT 

Gobble your way 
through a maze- 
Ghosts, power pills etc. 
All machine code- 
Super fast action. 






MAZE DEATH RACE I KRAZY KONG 



SPECTRUM 16-4a<£4'95 
ZX81 16K £3-95 



Drive through a giant 
maze, 9 times the size 
of the screen, picking 
up points as you go- 
but watch out for the 
the other cars, rocks 
oil and ice. Superb 
machine code game. 
Highly reoo mended. 

SPECTRUM 4SK £4-95 
ZX81 IGK £3-95 



All machine code 
version of the popular 
arcade game.This 
program has all the 
features of the original 
and is every bit as fast. 
3 different screens 
make it difficult to 
beat. 



ZX8! 16K 



£3 95 



HOPPER 

Entirely written in 
machine code. This 
excellent version of the 
arcade game is very 
addictive. See if you 
can get the frogs back 
to the lilly pond, 
(Available end of 
February 1983). 



ZX81 16K 



£3 95 



PSS makes /Machine , 
Code Redundant! 

Now there is no need to spend long 

tedious hours writing and debugging 

your programs in laborious machine 

code- letMCoder from PSS do all the 

hard work for you- 

MCoder is the first real integer compiler for 

The Sinclair Spectrum This very sophisticated 

piece of software will simply translate basic 

programs into machine code for you, giving an 

average speed improvement of the order of 75 

times although in certain cases the improvement 

can be as much as 900 times faster. 

/Vf CODER WAS DESIGNED TO BE AS SIMPLE AS POSSIBLE TO USE.. 




Load yVICoder, 



Write or load your basic 
program as normal. 



RUN and debug 
your basic 
program 



Compile your program using a single print 
USR command. If you have made a mistake 
/HCoder will tell you exactly where.allowing 
you to correct it before it is too late. 



7-95 



As an additional feature basic programs 44CODER FOR THE SPECTRUM f* ,QC 

can be compiled and "Stacked " above 06K or 48K) Costs only ** *9 

each other in memory - giving you THE ZX81 VERSION IS ONLY f .OR 

true flexibility in your programming, # w9 



Eftt+A* TUa DC C *° Srlow our * a ^ n ' n our product we are offering 

dO £1000 in prizes for the best Spectrum programs 

*#%#%fcJ|DET l ITIf\Ikl using /VICoder. They can be GAMES, 

WV-ZlYlrC III I Kjn EDUCATIONAL, UTILITIES, in fact anything you care 
to write —The only restriction we make is that they must be written using /VICoder. 



1st. prize -£500 

On/4 r\ri -yj% a portable colour tv 

zna. pnz©- valued at £250 



IO runners up- 

WILL EACH RECIEVE A PRIZE OF £25 



WE ALSO GUARANTEE TO MARKET THE TWO WINNING PROGRAMS UNDtft A ROYALTY AGREEMENT WtTH THS AUTHOR * CLOSING DATE 31st MAY 
RESULTS WILL BE PUBLISHED IN SINCLAIR USER MAGAZINE ENTRY FORM ENCLOSED WTTH EVERY COPY OF /MCO0€R„ 



SEND CHEQUE OR RO. TO PSS 452 STONEY STANTON ROAD COVENTRY CV6 5DG. 



(continued from page 138} 
what you are typing so go slowly. Now type 
Run and Return. Now you have to input the 
size of the grid — the number of tetters in X 
and Y directions, try 18,18 and press Return. 

Xexi yau arc asked for the number of words: 
20 is a reasonable amount. Then you type in 
the words, be careful if you have no screen. 
You will have to wait a while as it fits them in, 
if the screen border goes red it wants you to 
enter a different, preferably shorter, word. 
When it wants another input this will be the 
title. After typing that it prints the solution plus 
the puszte and list of words. Press Y for 
another copy of the puzzle or press N for 
entering a different one, 

Those with expansion fitted will have no 
difficulties. The printer used was the Seikosha 
OF-I00VC. 



SOFTWARE Flit 



(lisling continued from page T38J 

3B5 QPZH3,* 

367 IHPIJT'TITLE-iTL* 

3S9 CT-IHT<4e-LEMi:TL*Sl CT*«-TB*+MIDKS,TR*<CTJ,2J 

389 PRJHT»3 ■ CHB*i; 1 4 > "SOLUTIOH r " I PRItJT*3 

333 FORJ- 1TCJV FORI -1 Tax: l^QfCI, J>»""TKEM»iriNT«3, " "J 

35*5 FRINT*3 , QtC I . J> , : H£XT ' PRIh"T#3 ' NEWT ! PR IHTfJ ! PR JHT*3 ' FRINT#3 

400 PRlMT#3,CHH*Ci't>CT*TL* , PftIHTt3,TXt 

410 FORt-lTOJt:FfJflJ-iTOV-IFG*a,J>- ,, "TMENGK;i, J}-CHRf CFNR<£G)+64) 

428 HEKTJ.I 

4£S PRIHTM,CNt"/' s'FORK-^TOa^-PRINTM,"-"; HEKT PRINTW. "-."OR* 

438 FBRJf-lTOV PRINT«,TV*CH* B I"; -F0RI-1T0K-1 

440 Pf?IHT*3,G«i, J)" -; NEXT PRINT#3„ 0*<X, J>" J"0R* PRlNT#3,'«f Cti* " f'"CR*" l"0R*- NE 
XT 

441 PRINTS^, TX*CN*" «> ; FQRK-£T02*M ' FRINTB3, '■-'■ I NEXT- FF1NTN3, "/■ 
445 Cl*-CHRt < 1 6 > +"K" ' C2*»CHR*< IE J + "3Q-' 

44S PRINT#3 , PRINT*3:PRIHT#3,T«* 

447 flB"iMT(K/3+. 5>+l 

43CJ FORI - 1 TOBB " PRI MTK3 , W*< I >C 1*W* C I +PE5 C2*U*C I +P,B*2> : NEXT : PRINT#3 1 CLOSES 

AiSG PR I MT" SMOTHER COPY <V/H > " 'POKE 19*,$ 

473 OETR*: IFfl*0 , -yP-NDR*0 , 'N l, THEN47 r e 

490 I FH#- ■ V " THENCFEN3 , 4 ■ PR I NT#3 ■ DDTQ40e 

490 RUN 

see bptp,:, a. i, i, a, 1,-1,1,-1,0- -i,-i,^-i, 1,-1 

6015 FOR I -1 TON 

610 I NPUTWf = IFWf *CHRt^ 1 3 > THEH61 

<?fl iJl' T l.-J* MF^T ■ SFTSION 



S3935S22) 



Drumbeat 

David Squires, 
St Andrews, 
Fife. 

This SHOUT program, written for cither 
version of the ZX Spectrum, expands the idea 
of machine -code sound eiTecis to produce a 
rhythm K enff racor, 

It is deliberately not too long or elaborate as 
this would mean losing some of the speed so 
essential to the program. The program itself 
suffers from the Spectrum's usual lack of! 



volume but even without headphones or 
amplification, some fairly impressive rhythms 
can be produced. 

You have two instruments at your command; 
■in.' bass drum find side drum wills tmit Wbfcn 
the program is run, it asks you for first the 
length of [he note of the bass drum, then the 
length of l he note of the snare drum. It then 
asks you for the number of bars the rhythm is 
to be played and finally the rhythm the 
machine is to play each bar. This is fed into the 
computer as a string of letters, with B for a note 
on the bass drum and S for a note on the snare 



drum. The other letter ihat can be input is P, 
for pause. Two or more can be written for 
longer pauses. Therefore BBSSPPSBBP would 
be read as two notes on the bass, then two on 
the scure, a short pause, another on the snare, 
two more on (he bass and finally a very short 
pause. 

Incidentally, if you arc using headphones or 
amplification* the Mic socket gives a more 
faithful reproduction of the sound you hear 
from the Spectrum's own speaker but the Ear 
socket gives a sharper, louder, more percussive 
sound. 



1© REM ***RhythRi 6e ne r a to r ** * * 


11© FOR *=1 TO b 


a<3 REM *FOT i6/48k ZX SpECtUUt 


120 FOR vsl TO CLEN 3$) 


30 GO TO 60 


130 IF a*(V>="b" THEN GO SUB 4-0 


4-0 POKE 32505, (lb*U/2: POKE 3 
2507,1; LET C=USR 32500. RETURN 


14-0 IF a*(W)="S" THEN GO SUB 50 


150 IF aj(v) s"p" TrfCN PAUSE t + f 


50 POKE 32505,(ls#lJ/£; POKE 3 


V = 0) 


3507,0: LET c =USR 32500: RETURN 


IS© NEXT V: PRUSE U£t=fl) : NEXT 


50 CLEfiR 32*39 


h : STOP 


70 GO SUB 300 


£00 FOR 3=32500 TO 32523 


30 INPUT "Tempo (0-S) ?"; t 


210 READ n: POKE a,H: NEXT 3 


90 input "Lenth bass drum ?te- 


220 DATA 6,1,197,33,15,1,17,1,0 
, 229, 20S, 181,3, 225, 17, 100, 0, 167, 


51 "j Lb: INPUT "Lenth snare ?C0-s 


)''; IS: LET Ls = LS*5: INPUT "NO, b 


237,90, 125, 254-, 255, 32, 237, 193, 16 


firs'? •*; b 


,230, 201 


100 input "Rhtym ";a* 


230 RETURN 



Millipede 

M G Crosstey, 

Hey WOOd, 

Lancashire. 
This PROGRAM is written in Jupiter Ace Forth. 
It is entitled Millipede and b based upon a 
program written by Andrew Weckes in 
Spectrum Basic published in Your Computer, 
February 1983. As there is a great shortage of 
Ace Forth software 1 hope Mr Weekes will not 
mind my usinc. his algorithm - 

1 have tried to use descriptive colon defini- 
tion names in an endeavour to make the coding 



self-explanatory. However, this is at the 
expense of memory and is not strictly 
necessary. The program as it stands occupies 
approximately 2K, 4 bytes } and requires a 
memory expansion to the Ace — I use a 
converted ZX-81 RAM pack. It may be 
possible, by cutting out the frills, to reduce the 
memory requirement and still have a playable 
game using the standard RAM only. 

In the colon definition Once-More she word 
Millipede is used. At the time Once-More is 
being defined Millipede does not esist in the 
vocabulary. Therefore, it is necessary to define 
Once-More omitting Millipede and then when 



ail the program has been typed in, edit Once- 
More putting Millipede in its correct position 
and then redefine Once-More. Anyone who has 
used the Ace for a short time will understand 
the procedure, A simitar situation — recursion 
— is covered in the Ace manual chapter 3, 
exercise 7, page 53. 

One interesting definition which I think is 
not covered in the Ace manual and which could 
be useful elsewhere is Screen-Peek. This colon 
definition expects the stack to contain the row, 
column prini-head position and returns with 
the ASCII value of the character at the print- 
head position on top of the stack, 



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(continued on page 143> 



YOUH COMPUTER. APRIL 13S3 141 



DOWNSWAY 



ELECTRONICS (UK) LTD. 



MORE MEMORY FOR YOUR 
ZX81 OR SPECTRUM! 



7^7 N E W! 32K RAM FOR SPECTRUM 





MEMORIES 

FOR THE 

ZX81 



The DowrlSway 64K Memory* Slots directly on to the 
computer, without needing an additional power supply, or 
adding any extra load to the internal 5v regulator. Trade in 
yourold 16K RAM Pack (any make, any age, any condition) 
for C1 2.50 against a Downsway 64K Memory to bring the 
price down to only £47-45 plus p & p. Without trade-in, it 
costs just £59.95 plus p & p — still incredible value) 
If you only want 1.6K of memory tor your ZXB1, the 
Downsway 1 6K RAM Pack off erst he same benefits of high 
quality and low price at only £24*95 plus p & p. 

Both memories measure only 2% x 11& x 1 in. and are 
supplied with a foam cushion strip to provide added 
mechanical stability. 

* Reviewed in ZX Computing Aug/Sept 1 982 and Popular 
Computing Weekly 22/7/82. 




A full 48 K of memory for the 1 6K Spectrum — Simple D l.Y. 
installation by just undoing 5 screws and plugging inf 

For Issue One machines (with light grey keys) — a RAM 

board of advanced design, using "state-of-the-art" technology 

— only £42.50 plus p & p. 

For Issue Two machines (with dark grey Keys) — a simple 

plug-in kit of I.C.s which fit straight in to the sockets 

already provided-c-nly £32.50 plus pSp. 

Both come with fully detailed, illustrated instructions. 



Nai u rally Downsway add-on memories are f u Ny lested and guaranteed, 
but should you be dissatisfied tor any reason, rust return the 
memory within 14 days for a full refund (and your old 1 6K RAM 
pack, where appropriate). 

Please allow up to 28 days for delivery. 



DOWNSWAY ELECTRONICS [UK) LTD, DEFT, H t DOWNSWAY HOUSE, EPSOM ROAD, ASHTEAD, SURREY, 

My ch«qu#/P.OJMonev Order fcs «ncl«*d 

PI ease dcdil my Barcl Jiycarrj No. 

Namo: 

Ad<Jr*S«: ,....,, 



Please 


send rne: 






Oty, 


hfcm 


Prfee 


Total 




32K RAM Board (Issue 1 Spectrum) 


£42,50 






32 K RAM Kit (JSSUQ 2 Spoglrumj 

64 K Memory for 2Xti 1 At trade-in pf iCe 


E32 50 






t4r,4S 






S4K at normal once 


£59,95 






16KRAM 


£24.95 






Post A Etackma 




C200 




Total 




£ 



Viking 
Software 




CBM 64 AND 

VIC 20 SOFTWARE 

FROM VIKING 

* BASIC FRENCH learn and test your knowledge of everyday 

basic French , ■ ,,,..,,..■,.,. £5,95 

•FRENCH TEST now prove yourself and test your memory of 

common words and phrases. , .,,„.,, r , , £7,95 

PONTOON gamble your money away in our casino with this 

favour tee card game , . , , , . f 5.95 

DRAUGHTS the familiar board game for all the family . £4.95 

OTHELLO can you outwit the computer in this testing game of 

strategy , „ £496 

3D ESCAPE you have set the bomb on a time limit but cen you 
escape th roug h the corridors of the enemies castlo- ........ £5.96 

"STOCK ETTE cassette based stock control for the small 
business, Can produce printouts if required. Full cost & selling 

prices etc £14.95 

COD EM ASTER break trie hidden colour code set by the 
compute* ..,,.., ..,.,,..,,,, £5,95 

"•COOEMASTEH NOW AVAILABLE FOR THE 2X tf> ECTUUM"" 

ft&MT iptrci'Y VrC X or CBM 64 when otdtttftg. 
'ftecfueif » mtinrtwrH n/SK iMrr FA/H on WC 2D. 

Qttkr mqu'rms wefcom*. Qmitty io/nvmr prvffucn* tna pn-keyed by rrt* trpcrtt 

Pfease make cheques payable to: 

VIKING SOFTWARE 

Unit 3 Meadow View Browston Lane, Brows ton. 

Gt. Yarmouth NR31 9DP 



ZX SPECTRUM &> ZX81 
EDUCATIONAL SOFTWARE 



Spectrum Junior Education €5.50 

Use your Spectrum to help your children with their school work. 
This cassette contains eight attractive, Easy -to use programs for 
the 7 to U age group. 

Topics include English comprehension, spellings, homophones, 
junior science, maths and history. 
» Entering your own questions and answers allows you to adapt 
two of these programs for exercises in any subject area, 

* Moving colour graphics and sound are extensively used to 
improve motivation. 

* Use the "draw" program to produce pictures, maps and 
diagrams. 

Suitable for the 16K or 4SK Spectrum. Program notes are 
supplied, 

O- Level Chemistry (CI) £5 50 

This cassette contains four clearly presented revision/ tutorial 
programs. The subject matter has been carefully structured to cover 
the most important aspects of: 

* Elements, compounds and mixtures. 

* Structure, bonding and properties, 

* Redox, electrolysis and the activity series. 

* Acids, bases and salts. 

43K Spectrum and 16K ZXB1 versions of the cassette are available. 
PJeese specify which you require. 



Professional Computet Assisted Learning materials from: 

CALPAC COMPUTER SOFTWARE 

108 Hermitage Woods Crescent, St Johns, 

Woking, Surrey GU21 1UF. 

Overseas orders: £6.50 ($11,601 per cassette; includes AIRMAIL 
postage, 



142 VOURCOMPUTER, APRIL 1SS3 



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Blitzkrieg 

Martin Exati, 

Drayton, 

Nofwicb, 



WRITTEN FOR a fulty expanded Acorn Atom, 
this program uses Kigh-rcsoluciori graphics and, 



iht chaTaciers which arc defined arc placed in 
the fluating-poiiH variable space. The program 
uses a machine-code routine to draw the 
characters on the screen. If you succeed in 
desi roving ail the buildings then the plane will 
land and then take oft' again for another go at a 
more ditlicuh level The program is written in 
MibriuiiiEiL's and includes. Rem statements so it 



should be fairly easily converted io other 
micros. The height of the buildings depends on 
the difficulty level which is set in line 3120 — 
the higher the number is, the higher the build- 
ings can be. There are buildings all across the 
screeo and they all have to be destroyed before 
the plane can land. Only six sections of (he 
building can be destroyed with any one bomb. 



148 GOSUB 1B«^REM MftCHIHE CODE 


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YOUR COMPUTER. APRIL 19S3 143 



SOFTWARE FILE 



tGonitrtued from previous page) 

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F>C- 



Multiline delete 



Chris Detiarocds, 
A thens, 
Greece, 



JJ-JJ 



THE LACK of a Delete command in JiX-81 
Bosk has been iti my opinion a major short- 
coming io » machine where (he lack of Data/ 
Read, the lack of a machine-code monitor and 
the limitations of memory have been forcing 
programmers to create and then line-by-line 
Jt-k-ic lengthy loaders and initialisers. Just 
think of the initialisation program nt Simon 
Lane's Dog Race — Your Computer July 1982. 
It comprises 126 lines. 

Such reasons have prompted me to write the 
Multiline Delete routine. It jusi takes S \ bytes 
and can be used without problem m both IK 
and I6K systems, in last or Slow mode, The 
routine deletes any number of any program 
lines — including line — contained between 
two given line numbers. — Poked to locations 
Fir$| L and LaslL, see programs. While - and 
this is most important — conserving all existing 
Basic variables. 

The routine i\ relocatable with no changes to 
be made when moving it up or down in 
memory. The only point needed to be taken 



into account is the locations of the two words 
First L and LastL, 1 consider it more useful to 
move it above RAMiop and have it sit there 
during Loads and Saves. Thai is why I have 
written an optional relocator occupying 12 
more bytes. You can easily omit that if you 
wish to do so. 

The routine is written around two very use- 
ful ROM routines. The first, starting at 
09D8H, returns the starting address of a given 
Basic line in KL and is used to determine the 
limits of the block of memory that is to be 
deleted. The second, starting at 09ADH, 
changes all pointers — that is 3 system variables 
between DFilc and STKend — that do not 
point lower than HL, by adding them to the 
value in BC. 

1 have written a shon Basic program 10 load, 
Lues 100 ISO, relocate, lines 10-30, drive the 
routine arid also demonstrate some of u* 
features 

Create a I Rem statement with 66 full stops, 
arid then type POKE 16510.0 

and key in the Basic program. SJow type Run 
and enter the hex code. When you have 
finished and checked it, type Com and start 
your cassette recorder. The program will be 
Saved under the name Vcl and then automatic- 
al I v Run. Lines 10-20 will relocate the Del 



routine to 7FQ0, while lines 10-70 will use the 
same routine to delete unwanted lines 0-199. 
When you now List, you will find yourself left 
wit Ji lines 900 onwards. Type Goto 9000 to 
discover that AS has been kept intact. You can 
now use the program through the Basic driver 
— lines y988-9999 — and its operation should 
present no problems. However, you should 
note some of the tbl lowing points: you do not 
have to enter the exact starting and finishing 
lines of ihe block you want deleted. 

The routine usually — but noE always — 
causes the Basic program from which it is 
called to hall the report code. 

Under normal operation the program cannot 

crash- But never enter a first line number larger 

than the very last line of the resident Basic 
program. Also, avoid last line numbers larger 
than 161S2, First line numbers should never be 
larger than last line numbers. 

IK users will probably want to leave the 
routine sitting in the Rem statement, Also, they 
will have to change the locations of First L and 
LastL in memory by changing their references 
in the hex listing — locations 16525-24 
respectively. 

Calling addresses arc: 

USR 165 1 4 for the Del routine if not moved 
USR "IS56S for the Relocator 



— 



BT ; 16 



Ui 



lENOTh :?o 



DEL; 
LB HL, TFIRSTL) 

CHLL 090W 

PUSH HU 

PUSH HL 

UP KL, ILP5TL1 

INC ML 

CALL PCSDBM 

EX DC, ML 

LD HL, tpFILEl 

AND ft 

SBC ML , DE 

JR NC.HOLflST 
LAST. 

LD DE, (£>FILE> 
HOLRST ■ 

LD ML, tt-LlNE) 

l*USH HL 

FIND ft 

SBC HL.OE 
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CX DE.HL 
POP BF 
POP DC 
PUSH RF 
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CD 1>U 09 



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LD HL i«8JH 
LD PC , 7r«BH 
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PET 



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am let e*uSR 16566 

DO* POKE 3B7O0,4 
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S« POKE 38702 , 3B« 
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I *J DESTINATION ADDRESS -CHN BE 
CHANGED TO YOUfi REQUIREMENT*. 



7LX *<t» FBffl^t 

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CRND9 GOSUB 7B, &? 

FftST y G3SUO "■ FA* 
&CN PRINT G03UB JX F 
B ? FAST HT LPRINT 

GOSUB BTRN 
CHB. CiEtLLflROCHS. 
RTMEHS GREECE 
5* BVTCS OF H/COM 
TO PL LOU ¥QU DELETE 
OF PRO^RAH L IME3 UH 
DESTROYIHO TME CXIS 



7B LET 

99 REM 

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9994 POKE LL,B-£5S*INT (BS2S4J 

9997 POKE LL + l,llMT (H.^56) 

999B PRINT 6 

9999 LET O-USR il27*S56l 



Sound editor 



J W Harrison. 

Wiggn, 

Lancashire. 



MW 



SOUND f.ditor for the Atari 400/SOO runs in 
16K and use* rhc variables: V, K, D, L, where 1 



V J* the Voice or sound channel selected, K the 
note, D the distortion factor and L the loudness 
or volume. A ^recn pointer is used to indicate 
the last sclcclien keyed in. The program allows 
;or cither one voice or all four to be used 
singularly or together 
To switch off anv voiccj key in: 
V. 0.0.0 
where V is the voice to be switched off: far 



example 

Sound 1.0.0.0 
switches off voice 1. 

Atari users can relet to the hardware manual 
for lurther guidance in the us* of disronion as 
some ecmbinaiions of V, N. I), I. will cancel 
out to produce silence. The program is self- 
explanatory as it runs and Rem statement*, in 
the listing help explain how ii is put together. 



10 REM << SOUND EDTTOR » 


60 ? H6;"*»t EDITOR t»t" 




15 RJEfl * by J.H.Harrison t 


70 POSITION 3,12 




16 REM ft SET UP TITLE PAGE *t 


80 ? #6| "PRESS fSTARTJ" 




20 GRAPHICS 17 


90 POSITION 5,14 




30 POSITION 3,4 


100 ? #6i*T0 BEGIN" 




#0 ? »6;"<*« SOUND <**" 


110 SOUND 0,66, 12. S: SOUND 


1,60, 12, B 


SO POSITION 3,8 




(continued on page 1 49) 



144 YOUR COMPUTER. APRIL 1961 




IDEAL HONE 
FOR YOUR 
HOMEXOIHPUTER 




The System Care Desk - made specially for 

home computer systems. Designed as a neat, 

smart piece of furniture for your home. 

£49-95 




■ Supplied as a f fat-pack. Easily 
assembled. Full irsiructions 
provided. 

• Smart teak effect finish. 

• All cables can be nearly and 
safely 'hidden.' 

• Economically designed, 
Sliding shelf positions the 
keyboard at the fight distance from 
the screen: to suit you. Slides away 
after use. Saves space 

MIHIAJURt 



• Easi-glide castors allow you to 
move your computer installation 
where you wan I it. 

• Houses computer, disk drive / 
cassette recorder and monitor, with 
ample space for tapes, boohs etc. 
Overall heigh! - 0.63m 
Computer shelf height - 0,70m. 
Width - 0.70m. 

Depth (with shelf closed) - 0.38m. 



Exhibited at the P.C.W. Show 
and the Northern Computer Fair 

And now including design features based on our discussions with home 
computer users. Send for yours TODAY. 



»■ "■*"■**■■■ iff ■■■ ■iaifH" «■■■■ lr ritit ttiiimui 



• Til 



IIP ■■ ■' l-f-l- *■ + *■ m 

l-l-il l-l-l- ik 

■ ■■Fill III^MI - 



I 144«HI 



At home w ft h your comp uter. 



NOW AVAILABLE TO YOU 
BY MAIL ORDER DIRECT 
FROM THE SUPPLIER. 

Micro Aids. 2 Boston Dose. 
Culcheth, Warrington, WA3 1BR 



ORDER BY FREEPOST - send the coupon or order in writing along with your cheque or postal order in an envelope 
- no stamp needed. Please allow up to £8 days for delivery. And there's a f 4-day money back option, in the event 
that you re not fully satisfied with your purchases. 



-^* =) l 



FREE 



Tidy Sal*FollY<"*" lal( * 



A 



~^-\ 

w 



;v 



A p»c* ©l cabit 

Hdieiwiin every 

dflth Ord«(M , '_ -f^\. 

Towinurviaffr 555- 

op*tathsn and c^5** 

improve C^S** 

appearance. - -_J^ 



L N 



To: Micro Aids, FREEPOST, 2 Boston Close, 
Culcheth. Warrington. WA3 19R 



order] 



GTY ITEM 

System Care Desk . 

4-Way Master Plug . 



ITEM PRICE 

_ £49.95 

_ £8.95 



TOTAL 



Post / Pkg 
I enclose a cheque/postal* order payable lo Micro Aids for £ 

* Please <toie;* a appteabte, 

Signature 

PLEASE PRINT 

Name: Mr^Mrs/Miss: 



£4 95 



Address . 



Tel: 



FR EE POST ■ no SUmp needed. Pf Jut app'y to U.K. only. E i port prices on .ipp l<c ,i1 ion 



At last 
A range of software 
thats as well desi 



as the Dragon 




Six months ago, most computer 
users thought a Dragon was 
something out of an adventure game. 

Howtimes change. Nowadays, its 
almost impossible to pick up a 
computer magazine without reading 
some new tribute to the Dragon 32. 

THE FIRST 
FAMILY COMPUTER 

We called it the first family 
computer And we believe that much 
of its success derives from the fact that 
it has been superbly designed for the 
job it has to do. 

Design that incorporates 32K 
RAM of memory at a real value-for- 
money price level. 

Design that utilises the advanced 
6809E microprocessor. 

Plus a range of features that help 
make the world of computers access- 
ible to first-time users, Like colour J^ 
drawings. 5 octaves of music. 

And plenty of power and 
versatility to keep up the 
interest as your experience 
increases. 



SOFTWARE TO MATCH 

Designing a range of software that 
does justice to the Dragon was a task 
we approached with as much care as 
designing the computer itseli 

The results are now available - 
games, educationalprograms, hints on 
programming - 
conceived by 
some of the 
best software 
houses in the 
world, to help 
users get even 
more out of 
their machines. 





TV not included in price- 








G raphic Animator 
A cassette that makes 
use of the Dragoris 
ability to draw on the 
screen. It shows you 
how to create simple 
cartoons - then bring 
them to life. 

Personal Finance, 
This cassette allows 
you to keep track of all 
the family's finances, 
from bills to bank 
statements. 



Ghost Attack On 
cartridge. Youre in a 
maze, and you must 
find your way out, But 
you're not alone - 
youre pursued by 
ghosts! 

Chess, A great 
partner to play against 
again and again - with 
one major drawback 
It's very hard to beat. 
Test yourself against 
nine different levels. 
On cartridge. 

Typing Tuton Only 
a keyboard as sophisti- 
cated as the Dragoris 
could allow you a pro- 
gram like this. You use 
the Dragoris own key- 
board to leam to type. 
On cassette. 





Cave Hunter, 
Finding the hidden 
gold is hard But 
surviving the attacks 
of malevolent crea- 
tu res may well prove to 
be impossible. Cave ' 
Hunter is on cartridge 

Dra g on Selection. 
A cassette of utility 
programs, allowing 
you to create your own 
database. Write your 
own tunes - or learn 
other language 
vocabularies. 

Starship Chame- 
leon. A cartridge game. 
You find yourself 
under attack by the 
dreaded Gabolators! 
Their task is to take 
your planet - yours is 
to protect it. 

Computavoice, 
This cassette actually 
enables your Dragon 
to speak to you. 

These are just 
some of our titles, and 
every month, we'll be 
adding more and more. 
What you get out of a computer 
depends on what you put in, And with 
a Dragon 32 and Dragon software, 
there's enough challenge and 
satisfaction for anyone. But then, that's 
what it's designed for, 

DRAGON 32 

The first family computer. 





16k RAM Cart 

Hon switchable 



hi 



for VIC-20 More memory for vour VIC-20 



m^..^...,*.^..!^. 



s**^ 





while stocks last 



More sound from your ZX Spectrum! 

Echo 

Not only more sound, but better sound and a wide range of 

other facilities! 

Control Volume, and adjust tone of sound' 

bad and Save without switching leads! 

Audible cue facility for tape programs! 

DIN compatibility! 

No additional power supply needed' 

Attract] veJy cased- looks good 

-SOUNDS GOOD! 

Only £23.50 




More memory for y our Jupiter Ace 



Pacer 

The uniquely expandable 

16K RAM pack 

Similar concept to ZXPANDA but for 

the incredible Jupiter Ace. 

Attractive, solidly built 16 K RAM pack 

with the facility of expanding to 32 K 

by plug-in module. 

For more power to faster FORTH . . . 

you need a PACER! 

16K Expandable RAM £29.95 

1SK Expansion Module £19.95 




VJXen RAM Cartridge for the VIC-20 

Switchable between 16 K or 8K + 3K. 

Gives you the option of full 16 K RAM or 8K and 3K SAM in one 

package. When added to a Standard VIC-20 

gives 1638* bytes of extra memory in 

memory blocks 1 and Z or 

3092 bytes of extra memory 

into the 3K memory block AND 

8192 bytes of extra memory 

switchable between memory 

blocks 1 and 3. 

Fully compatible with available motherboards/ modules, 

Simply plugs into the rear expansion port of computer 

No re-addressing of existing BASIC programs needed. Only £44.95 




Tandem 




Expandable Expansion System for the VJC-20 
Gives 4 expansion slots for VIC-20 cartridges. 
Custom-designed case. Plugs directly into 
computer. Further expanded 
by using TANDEM System! 
ROM socket for expansion. 
No extra power supply needed 
Only £34.95 



F 

1 1 Aid 




Stanechip Electronics., Unit 9. Tile Brook Industrial Estitt. Deidbrook Lane, 
AldenM. Hants, telephone: 107521 318260 
Host forward me thi following products: 



All prices are inclusive of VAT, P«1 & Pitkin* (or U.K. deliver i« [owrseji ,*dd 15%| 

Nim*. ,.,,.,..... , . . 

Address:. ............. > 

STONECHIP 
ELECTRONICS 

" more ways to make more of 

L your computer" A 

IM Ml H IM ■ iV iM 1M iM hJ 
DEALER ENQUIRIES WELCOME Delivery appro* 14 days 



SOFTWARE FILE 



{continued from page 144} 

113 REM «» CHECK FOR CSTART] BEING PRESSED tt 

120 IF PEEK ( 5327? K>6 THEN 120 

130 SOUND O,O,0 t 0iSGUND 1,0,0,0 

135 REM « SET UP GRAPHICS 1 WITH TEXT t* 

140 GRAPHICS 1 

150 ? "SELECTION WILL BE DISPLAYED ABOVE ■■ 

160 ? "WHICH VOICE <Q-3>™; : INPUT V 
170 IF V>3 THEN 160 

175 REH tt CLEAR TEXT: PRESS t ESC], THEN 

176 REM PRESS L CTRL 3 AND C CLEAR J TOGETHER 



tt 



1B0 
190 
200 
210 
220 
230 
235 
240 



260 



? "}-|REM tt CLEAR TEXT tt 

? "NOTES GD FROM HIGH(0> TO LOW (255)-" 

7 "WHICH NOTE <0-255>"; : INPUT N 

IF N>255 THEN 200 

7 H }"sREM tt CLEAR TEXT tt 

? "DISTORTION EFFECTS VARY < EXPERIMENT}-" 

? "EVEN NUMBERS ONLY — -" 

7 "WHAT DISTORTION IQ-14J ";: INPUT D 
245 IF DM4 THEN 240 
250 7 ->-sR01 t* CLEAR TEXT tt 

f "VOLUME RUNS FROM QFF<0> TO L0UDU5)-" 



270 ? "HOW LOUD <0-I5>"; i INPUT L 

280 IF L>15 THEN 270 

205 REM tt DISPLAY SELECTION TD GRAPHICS SCREEN tt 

2TO IF V=0 THEN POSITION 0,0 

300 IF V^l THEN POSITION 0,4 

310 IF V=2 THEN POSITION 0,8 

320 IF V=3 THEN POSITION 0, 12 

329 RErt tt TYPE sound IN INVERSE VIDEO tt 

330 ? #6j "sound °|V|", "jN; ", "|D; ", "jL; * 

331 REN tt 4 SPACES BETWEEN LAST QUOTE MARKS tt 
340 SOUND V,N,D,L 

345 REM tt COLOR 26 SELECTS GREEN POINTER 

346 REM ** COLOR ERASES IT. POINTER USED 

347 REM tt TO INDICATE LAST SELECTION KEYED 

350 COLOR OsPLOT IB,0sPLOT lB t 4:PL0T Ifl t 8iPL0T lfl t 12 

360 IF V=0 THEN COLOR 28- PLOT 18,0 

370 IF V=l IHEti COLOR 28: PLOT 18,4 

380 IF V-2 THEN COLOR 28iPL0T lB t 3 

390 IF V-3 THEN COLOR 28: PLOT 18, 12 

400 7 "J":REH *t CLEAR TEXT t* 

410 GOTO 160: REM tt RETURN FOR NEXT SELECTION tt 

420 END 



Memory display 



/ K Biddte. 
Num&aton, 
Warwickshire. 



ass 



A J HYNDS* program, December Your 
Computer, is quite ;i useful idea tin memory 
display but has two distinct disadvantages. 
First, it requires about a page of user memory, 
aivd secondly Pane must be tillered in order to 
prevent the initial program being overwritten. I 
wrote [his machine-code program with these 



considerations in mind. The program uses no 
memory allocated to ihe user suite it is focaced 
in disc space ill &D00. Tlie assembled pcu^rarn 
requires about 225 bytes in &DO0 and five 
bytes at &70. 

To use the program ivpe 
HUN <CR> 
and wait until the prompt re I urns. Then tvpe 

CALL 5% <CR> 
The program should ihen wait until a four- 
digit hex number is input. It it does not, re- 
check the listing. 

In order for The program to operate, all 
leading zeros must be input. Scrolling is 



achieved by pressing -Shift and to exit, press 
Escape. The program can be called from Basic 
and trapped with the Statement: 

ON ERROR GOTO ; . . 
when the user press** Escape, The display 
format can be changed by altering line 820 to 
read 

JSR &FFE7 

All error checking has been made and will not 
accept alphanumeric* outside the range 0-9 and 
A-F. Incidentally, the location at &D7 returns a 
non-ASCII value of a keyboard input and 
Escape is [he value 240. 



40FORI= 


QTQ] ;f^ = JliOO; 


22D. 


CH2 


CMPM? 




410 




BNE LP3 


600 


JSR 


JFFE7 


790 




I.DAM170 


SI-PZs 


con 


290 




ECC LP3 




420, 


PUL 


CLC 


610 


LIiX 


J73 


900 


LP7 


JSR SfFEE 


SO, IN? 


LflXltO 


240. 


CH3 


JSR 1FFEE 


430 




CLD 


629 


Lilt 


S73 


BIO 




LBAM120 


60.LP1 


LPA MX,X 


250 




STfl S70„ 


X 


440 




LDXMOF 


630 


sn 


181 


920 




JSR SFFEE 


70 


L ft * IB 


240 




LOfl S70, 


X 


450 




LHA *?0 


640 


Lt)t 


*7* 


930 




, ; ■-. 107 


90 


BE0 3Pt 


270 




CHpNMO 




440. 


LP4 


AtiC 170 


Si8, LPS 


m 


390 


940 




Crt'-fAFO 


70 


JSR IFF Eh 


280 




PCS SUB 




470 




BEX 




930 




*E0 LPS 


t 00 


IMX 


290 




CLB 




490 




9«E LH 


670 


JSR 


JB370 


960 




IHY 


1 1 


BNE LPT 


300 




BEC 




490 




ABC A7I 


690 


TVA 




970 




BNE LPS 


120. get 


LtiT*0 


310 




SBC* J 30 




500 




STA *73,V 


690 


JSR 


.\95iA 


FJ80 




1HC391 


130- LP2 


Ll'XiO 


320 




SIA 370, 


X 


510 




CF'VllsOl 


700 


LI'A( JtSOJ . T 


B90 




Iri* 


140, LP3 


JSR JFFEO 


330 




JMP DK 




520 




PEG PNT 


71 


JSR 


SS&4A 


?O0 




BNE LT-ti 


ISO 


EKP#?1 


340, 


SUB 


CLB 




530 




I«T 


720 


LBA(«B0> T r 


910. 


LPS 


RTS;: 


160 


&CS LPS 


350 




SEC 




540 




BNE LFT 


730 


CHPN&20 


920HI-PI 


H ! *M , S = C1lftllZ + 


170 


ChPb^S 


3*0 




S6Clt*3? 




5 50. 


(■■ :< r 


;■-■!« 1 4 


740 


BCS 


LP* 


- 


ly^e 


i« start 


190 


BCC CH2 


370 




STfl *?0, 


X 


560 




JSR *FFE3 


750 


i-J'.-«»S20 




hdefrcs* (Up., > " 


170. CHI 


CrtP»6* 


380 


DK 


CPXNK01 




570 




LBA1V2 


760 


.IMF 


LP7 


930MEXT 




200 


*CC LP3 


3*0 




FEO HUL 




590 




JSR JFFE3 


770. UP* 


i: » <■' n i -' k 








210 


JHP CH3 


too 




INI 




5?0 




JSR JtFF£7 


790 


BCC 


LP7 









Forth connection 



P Sharp, 

Maidstone, 

Kent 



,jj 



This is Connect Four Tor the Aoom Atom in 
2K — 05K of ihis is graphics. The object is to 
get a row of four counters in a grid. This is 
done by using the Repeal key io move across 
the top and Shift to drop the counter. There arc 



sound cilects, a scute of each game won and 
alternate goes. 

The computer tells you whose move it is and 
inverts two counters on the winning line when 
a person has won. 



iee-ejL-0,*-BjF*i 

20CLEPR9 

30 IN. "INSTRUCTIONS Y^H'V; 1FV-Y CGS.x 

4BDIMARi4;I*e 

3BI-I+1;RA<I)-0jIF K13 G.50 

fiacLERfte^ft-eiD-SjiH-B^&^/T^aFiU-inejs-it+eiZ^ , ;-e 

70P.il2'- WINS "E* X WINS H Li?#Saie*S;?tfl8lC*S 

30I-I+li«Rn-fS9iF+I;?flflll-(tF8iIFIO2 G.98 

90I-B 

IBS l-I+liP*R+ljFj«#8B6*+flj?Ti«#F0jIFI<H u,!S2 

I J GR-fl-29 ; D -D+64 ;fl-L> j I FD< M49 I -8 j G . 1 0B 

*3ei"I+ljH-i8W4+Cj?K-»FFj>C+32>IF Kit G.138 
i-taZ-2+2>C-2iIFC <>16 I-BiG. 130 
138IF F-t K-UiC. 170 
IS0*X-TjO-tSF 



l70HR12-RRl2+ljIFF»fll2-43 G.u 

1 80?#6043-X i ?tB 1 34-X i ?tfl 1 3€-t i 4 

I90?i6l 37-T i ?i9l39»t90 1 ?#6 1 3R-T j ?(#8 1 3B-IHS 1 7WI3C-I0S 

2001-0 

210>IfljFtfll3»#0133+I,lF I<8 G.210 

220b 1-0 

230 J F( t#eaB2 >i64< we, 2ee 

24B1F?*B001O#FF G.c 

250C 230 

260IFQ»2;?C»S 

270C-#804S+I; I«I+2j?OX;0-2jWftITj IFI-14C,b 

280G.230 

290cIFC-i8043G.b 

300 IF C-«e043 M-6~fiR2,Rfl2-flfl2+'ljG.h 

310 IFC*#B047 M-6-Rfl3iflfi3-flffl3+IjG.ri 

(continued on page 15 J t 



VOUFI COMPUTER, APftIL 1993 149 



Just £4.95 1 



Mrw 
slimmer, 
lighter HAM 
Pack for the 
7X81 — no wobble 
proWems. and com- 
pletely reliable — fully 
printer compatible 



New SPACE TREK 

All the features of the favourite 

'Star Trek' game plus graphic 

warp drive and arcade type 

klirigon shoot- out make 

thrs program a 

must for the 

dedicated 

trekker'. 



.JR/ IBKRAM PACK 



mad, . 



Btytad 



Only £26.50! 



Buy the two together as a budget 
pack for only £29. 951 



Other JRS FAST LOADING 
t6K Programs for the ZX81 

£4.95 GAMES II — 3 arcade-style? machine code pro- 
grams [City Bomb. 3-D Battle. Gndball). 
£4.96 LOST ISLAND — An absorbing adventure pro- 
gram in which you are shipwrecked on a desert island. 
£5.95 GRAPH ICS TOOLKIT— 22 machine-code rou- 
tines that enable you to considerably improve the screen 
displays in your own programs. ('Good value for money' 
2X Computing Sept/Oca JssueJ. 

£4.95 BATTLE SH I PS — The classic game of Battle- 
ships and Cruisers — You verses the 2X81. 

TO JRS SOFTWARE LTD, 19 WAYSIDE AVENUE 
WORTHING, WEST SUSSEX BM13 3JU 



Otv. 


Item 


Price 


Total 




BUDGET PAC< 


L7995 






JRS t6K RAM Pack 


E2S.50 






SPACETREK 


F4 95 




: GAMES II 


£4.95 






LOST ISLAND 


£4.95 






BATTLESHIPS 


£4.95 






GRAPHICS 'OOlKI i 


f5.95 




"] Please tick tor tree catalogue Total £ 





(Note all prices include VAT, o&p) 
I enclose Cheque/Postal order/Money order' for 
£_ made payable to JftS SOFTWARE LTD 

Mr/Mrs/Mi(5 . _ - 

Address , 



19 WAYSIDE AVENUE. WOftTMIMQ, SUSSEX RH13 3JU T*(*phor>* 10*031 **69l 



"Delete ji applicable 



^itiiiiimiiiiiiiiiiimiiiiiiiiiiiiiiriiJiiiiiiiiiiiiiiirimiiiiiiiiiiiiiiiiiriiiiiiriMiiiiiiii^ 

I ST. GEORGE | 

| AND THE DRAGON | 

Software for the Dragon 32 



Can you sfay the fire breathing Dragon? Can you cross 
the slippery bridge and smite the magic stone to lift 
the curse from the castle and its beautiful maidens? 
Don't get roasted by the Dragon, and mind the river 
and pond. If you fall in, your armour will send you to a 
watery martyrdom. Using sound, the program also 
pushes the Dragon high resolution to its full 
capabilities. For joysticks only, 



= Only €6,95. Send to: 

| COMPUTER RENTALS LIMITED 
| DEPT. YC 

140 Whitechapel Road 
= London E1 

Telephone: 01-247 9004 

DEALER ENQUIRtES WELCOME 



Ir 



A 



v- <<?v<>- ~<o <p <<$-> ^ , 



#Vo 



¥K& 



&>■ 



y- -^ ^^<^_&ZS 



<? d?#X> 






^ 
V 






The RD Digital Tracer - 

featured in Your Computer January 1983. - gives 
you instant transfer of pictures and designs to 
ZX Spectrum and ZX 81. The introductory 
price of £4935 must end soon! 

The RD Digital Tracer is supplied with tracing 
sheet, software cassette and full instructions 
on use. For delivery within 28 days, send 
£4995 [payable to RD Laboratories Ltd] to 
Dept T at 

Ft D Unborntoriss Ltd 




[Oiler apples to UK trtfi 

Send stamp and ectonss tor detws of die 

RD 3100 Mcctter htertoce SvHjem for automate 

nvrtuwo. t«et and control 



ISO VOUR COMPUTER, APRIL 1983 



SOFTWARE FM 






(continued from page 14S) 


37BE. 


320 IFO#ea43 M«6~RR4 J RR4*FW4+'. ,G.h 


5BMF X«T Rfil4«l 


330 IFC-M048 H-S-Rfl5jRR3-Rfl3*ljG,h 


390 IF X-U flfli4«2 


340 IFO»804l> M»6-ftR7rRR7«RR7+ljG.h 


$0Bu?OXj 1-0 


350 1FC«#804F M»6-flflBiRR8-Pft9+ljC,h 


61&W+i; W-C;Y*0 


360 IFC-#B051 M-£-flfl9jRR9-Rft9+ljG.h 


S20IF I»l H-S2 


370G. 160 


630 IF 1-2 N-66 


390hIFf1<lC-£30 


640 IF 1-3 H-a 


390I-0jfl-0jft-R*l1 


630 IF 1*4 N*S4 


400J-I+«1i7C-S;C-C+64;?»<jP.*7jfl-R-ljIF ft-8G.ii 


fiBBfrU*H 


4i0G.46e 


S70IF TH-X R.Y<>3 Y-Y+1jG. 660 


4?0C*»8043jIFX-UjG.1 


eeeiFY-s c.r 


430K«UjO»tSe^.l7fl 


690 IFWOX G.?ie 


440xP,»12" COWCCT 4"'" " 


70QC.660 


450P. ' jn TO WIN GET A LINE Of o v X.IN fl ' 


710H— N;W-C 


4S0P." VERTICAL, HORIZONTAL Oft OlRGERNflLLINE" 


720W-U+N 


470P. " "CONTROLS M " "r*n TO MOVE" 


730IF?H-K R,Y<>3 Y*Ytlj&,720 


4B0P."«Mft TO DROP CQUHTER"" ,l t«o Minn onU";fl»a 


740IFV-3 G,r 


490ft*R+tlUfl!Ti IFR<530G.49& 


■ TgeiFKSG.SlB 


560R. 


760G.420 


3 1 0uT#8 1 34-193 , ?«8 1 35- #94 i?W8 \ 36-#8 1 j ?#8 1 37-W0C i ?*6 1 38-fBS 


770rU"U-Hi 1=0 


520T #6 1 39-»SD; ?*S13fl-#91 1 T*S 1 3B-*94j ?#ai3C-405 


?9B ?H-0i?r>O;fl*«i39 


33QLT..1UFB7D> IN. ''"ANOTHER GO Vj'WHj IFft-MjG.STfl 


790I»I+l.i?fl-Sm*R+ljP.*7yIFI<9G.799 


540IFRR14-0 F-i,flfli4-ljG,40 


6Wr#8136MI7j ?#B137*Tf ?#81 3e-#0E 


550IFF-1 RPl4-0jF-ejG.40 


610IFX-T E-E+I;G.530 


360F>1jC40 


eteiFx-u L"L+uc.s3c 



Bone idle 

W A Googe, 

Stevenage, 

Hertfordshire. 



m=m 



THIS ts a program for a 16K RAM ZX-8) , Ii is 
widely recognised that the prime function of a 
computer is to make life easier for us all, but to 
program one to play Patience for you must be 
the ultimate in laziness. My excuse is that the 
computer can play faster than me, and it does 
not cheat. The game is Clock Patience, and the 
program should be entered and Run. 

tn reply lo the L cursor the following data 
should be input, one number at a lime, reading 
the data across the page. Follow each entry 
with New line, and if correctly done, the last 
ennrv will produce a message 9/10. 
Data: 3. 20, 2. 21. 1, 22, 0, 23, 6, 23. 5. 24. 
4. 25. 3, 26. 1 0. 24. 11, 24, 10, 26, 11. 26, 
15, 23, 16. 24, 17, 25, 18, 26, 18, 20, 19, 
21. 20. 22, 21. 23. 18, 15, 19. 15. 20. 15. 
21. 15, 18. 10, 19. 9, 20. 8,21, 7, 15. 7, 16. 

6. 17, 5, 18, 4, 10, 6, 11. 6. 10. 4. 1 1 . 4, 6, 

7. 5, 6. 4, 5, 3 t 4, 3, 10, 2, 9, 1, 8, 0, 7, 3, 



15. 2, 15, 1. 15. 15. 12. 15, 1 I, 15. 10, 
15. 9. 15. End of daw. 

List the program and delete lines I to 10 
inclusive, by typing Line Number Newline. 
Do not use Run or Clear, or you will lose the 
data you have him entered, which is a list of the 
prim positions for the cards. 

You will need a copy of (his exciting 
program, so get your recorder into a recording 
mood, type <loto390, «art the recorder, and 

press Newfine, the program will Autorwi, 

The computer will shuffle the cards and set 
thtinouf in a clock-face pattern on the screen — 
ii deals at random from a new pack each time 
which amounts to ihc tame thing. Should the 
computer succeed in getting (he game to come 
out, it will stop with message 9/380 and Cont 
S'cwlme will start ii off again. 

If it fails, it will display the Ace that stopped 
it in the bottom left of the screen, and after a 
pause try again. Remember this is a program 
with hidden data stored within it, so to restart 
from a listing use Goto 1 1. 

The computer plays at about two games per 
minute, and if such haste makes you dizzy, an 
extra line: 



265 PA USE 100 
will slow things down a bit, or if you dislike the 
screen lump caused by Pause there is room for 
a dummy loopai that part of the program. On 
the other hand, if your patience is limited delete 
line 175, and insert: 

222 SLOW 

This will speed things up by not displaying 
the cards until after they have been set out. 

The computer starts play with the top card 
from the one o'clock pile. If you wish it to Start 
tn Ihc centre, change line 230 lo read: 

LET X = 13 
and alter the first subscript of the arrays in line 
370 to read IS also. 

If desired, the program can be altered to 
delete line 335. Replace it with: 

235 PRINT AT t20+ 1 **1|,0;D* 
236PRINT AT (20+ 1-*1i,0;-' "(two 
spaces! 

This will cause ihe card in the bottom left of 
the screen to flash, and demonsiratc a novel use 
of the * ' function to cause a slight delay — a 
good idea gleaned from somebody else's, 
program, and deserving to be more widely 
known. 



X 


DIM Cf < 13, i,a> 


M 


LET P.INT (fiNOtLEN B«J 4-1 




ff 


LET D**C»tX,VJ 


£ 


DIM R ( 1 3 , 4 , St 


lee 


IF P^S-INT <P^S) -0 THEN GOT 


B71 


LET T (XJ "T(Xt -1 


3 


DItt T*13) 


a I4e 




28 


LET X-UfiL C*(X.C,t3 


4 


FOR W«J TO IS 


110 


LET C*CM,H>B0*tP TO P^ll 




,^>85 


LET V^T (XI 


8 


FOR tt-i TO 4 


123 


LET B»»B#f TO p-ii*o*<p*a 


1 


^(»0 


Xr Y-B THEN OOTO 330 


e 


INPUT ft tN,H, 1) 


O 1 






310 


PRINT RT fl(X,Y, 1> ,fl(Jf ,Y,fft , 


7 


INPUT ft iti.H.Si 


130 


GOTO 1O0 




ni 




a 


NEXT » 


140 


LET C*tN L M> <Bi(P-l TO PJ 
LET Bi=E*t TO P-S)*e«lP*l 




ilS 


LET Bifi+i 


? 


NEXT H 


ISO 


T 


317 


IF R'Sl TMEW OOTO 37(1 


19 


STOP 


Q 1 






j*io 


GOTO 260 


11 


FR&T 


-■Pi 


NEXT li 




^30 


FOR N=l TO 100 


li 


PMMD 


i '0 


MEXT N 




;jb 


PRINT RT 21,fl, I>* 


is 


LEX n-i 


17B 


5LOU 




?*0 


NEXT N 


~o 


LET K»13 


LM 


FOR H«i TO 4 




ma 


CLS 


ia 


LET 0=12 


loe 


FOB M-l TO 13 




360 


GOTO 11 


40 


LET JmiX 


.' 00 


PftlMT AT flth.N,l) ,B(M,H,a) 




370 


PRINT ST Bll,i,l» ,BU,4.ai, 


38 


LET T«ie 


™0 






c*<x 


.Y) 


si 


LET e»- ,, ASSS35*3SsS37SeS.*>S.T 


NEXT M 




M 


STOP 


3JSeSK3AD2O3D4D306D7(>S[>9DTC<JDODK 


dad 


MtTXT N 




" 65 


GOTO 11 


OflC2CaC*CSC6C7COC9CTCvJCPC*CFIH»H3 


^33 


LET ft-* 




! M 


5RUE "CLOCK" 


MdM5HSM7HiH9MTMJHOMRH" 


i30 


LET X*l 




4<B0 


GOTO 11 


70 


fOR N-i TO A3 


a4a 


LET V«TlXJ 








-5 


LET T fN» ■* 


350 


PRINT ftT RCX.V.ll ,FHX,r,£> 


J 






ftO 


POP M*l TO 4 













Music maestro 



)m$&} 



Roger Keatl&y, 
Wolverhampton. 

The pr<w;ram allows the user to enter, 
modify, insert, play, load and save a piece of 
musk. The standard Dragon musk symbols 
are entered into a line where each symbol may 



be separately addressed. Music is entered using 
the E command in the form: 

E (START), I TEXT I 
Where Start is the Hirst position to place a 
symbol and Text the string to use — can be 
more than one symbol. If you enter on an 
existing symbol Modify is effected. Symbols 
can be inserted into the line using the 1 
command in the form: 



JISTARTNITEXTI 
Where Start is the position to start on and Text 
the symbols to be inserted there are no default 
values (or these commands. They should be 
entered in full. The music string can be played 
using the P command as follows: 

POJNE NUMBER} 
Where Line Number is the line to play — 20 
(cotttinoed on next page* 



YOUB COMPUTER, APRIL 19B3 >51 



SOFTWARE FILE 



(continued from previous page) 

lines arc available. Leaving ihe line number off 

will cause the Dragon to piay all the lines 

entered. 

The L command changes the line number 
which music i* entered juto. Use; 

L « II.INF NUWRrRi 

Do noi leate the line number off- The 
command New removes all the symbols from 
the lines, U$c [his to $wn again- When you 



have completed your masterpiece you can save 
it on to tape using the Save command: 
SAVE/tRLENAMEl 

Where Filename is the name you wane to call 
the piece. Similarly Load can be used to get the 
file back from tape: 

LOAD. (FILENAME) 

As the program does not test the symbols 
entered ywi must mate sure wha; you enter is a 



valid Dragon symbol.- If it is not the program 
will halt when you try to play the symbol. If 
this does happen you cart recover by entering 
Goto 50 — this will restart the program, You 
can then change [he offending symbol. 

[f you have been running a high-resolution 
graphics program before using ibis one, switch 
the Dragon off", then on again before loading 
this one, as the program uses PClearl to save 
memory. 



MtUlQHil Ht/Sli US ITER 



1$ 
20 

36 PCLEAM CL£Mt2&99 OM Ht<29> 
40 CL'l 

se cts 

69 print print print 

T9 PP1KT972.1 PRINT0922 FR(HT092 i 3 
Si) FOR r-i TO 3 
.<*$ FOR C'i TO ? 

iso fffiNrustm 'Wtc, 

116 WXT C 

12* PRlNTUSl H&'f,9, 

ne nextt 

140 PR{HTi&lNG**f.l2> 

tie futures,*, line \cl 

ii.e pfti<itti,-:8,rtt<CLy 

we ffljurwgfc sTxiNGHie, • "> 

190 PRlNT9t92, ' • 

199 PRINT 

299 FftlNT'IWUT COWIfttt STRING' 

210 LINE INPUT " y,C* 

220 !F lEFTtiC*. l>i>'F" THEN 299 

/..,! f m0 

249 IF LENfCt)>l THEN F'l PNt'MlOHTMCt, <LMH<C*>~±» 

Jjtf IF F*l THEN FH-rVtlLiPH*i:FLf>V MtiPNiGOTO 150 

266 F0* C't TO 29 t&$~HX**m<C> NFtff C 

2?* FA.HY ttXt.t*Xt' r - 0OTO IS* 

289 ', . . ENTER 

£90 IF tBFTttCt, !><>-£■ THEN 400 

3*8 FC'INSTR<2,c$, "."> 

Jilt Fti*VftLi.MIDt<Ct.2,PC-2>> 

329 iHtrftlGMTKC*. (lEUcC*y-PC>> 

SS9 St*tEFTt<nt<CL>.PN-l> 

3*9 B*~Bt*IHt 

359 IF PH>-lEMHt(£l>> THEN 570 

ofi» 6i*6**H(l(iHT*<tttai>.LEHin9<tL>>-<FH+LEH<lN*>-l>>> 

779 MKCLt'Pt 

3S9 GOTO 130 

3.*fl CHtNtOE LINE. 

409 IF LEFTt^Ct.2>^~5'L•• THEH 456 

*i9 CL^AHRIGNTtiCt, <LEN(C*>-2»> 

429 IF Cl>2& THEN PRINT PRINT" 29 LINES ONLY " * CL'l S0UHt>19&, i? 



4J9 PSfNT9jyt-5TP:NQIiS2'" "> 
440 GOTO 15* 

459 '. SAVE "" — - 

460 IF LEFTtiCI. 4><>r$AV£" THEH S79 
470 Ft'FIGHTHCt- aCffiC* >-*>> 

*90 PRINT PRINT -PRESS ENTER NHLN RECQR&EP REttOV 
4$8 IF iHKEYt*" THEN 490 

509 PKIHT PRINT'OUTPUT OF "Ff IN PROGRESS' 

51 OPEN "0". »-X>Fi 
329 FOR C*i TO 20 
530 PRINT 9-l,Hi<C> 
340 NEST C 

530 CLOSF ■-! 

560 6QT0 Iff 

370 IF LEFT*t<:*,4><>-l.0W THEN 690 

380 Ft'FIGHTKit- <LEN<Ct)-5>> 

S99 PRINT PRINT'FRESS ENTER WHEN RECORDER REHW 

600 if imev*'" thcn ton 

610 PRINT' INPVt IN PfimRFSS- 

£29 OPEN 'l",4-i,ft 

$39 PRJNT'FTIF J F*" FiWNft rtHO LOWING)' 

649 FOR C'l TO 20 

639 IHFVT *-l,t\KCi 
669 HEXT C 

679 CtOSf »-i 
o89 GOTO 49 

640 IF CtO m NEU m THEN 719 
700 RON 

710 '. INSERT 

729 IF LEFTti£*,l>O m l* tHLN 819 
739 PC*lNSTR<2,et, V*> 

7*9 FN* V9l % tnlT>*<Ct,2 r PC-2» 

730 J«*«*f ON Tl (Ct. <LEN(CD -FO > 
?69 &**LEFT*tN*<CL it <Pft-l>) 
7/0 m-&t*tHF 

769 Bt'BttftlGHTHNtiCL.}, iLENiH*(CL>i-PH*t» 

799 IF LENi$t)>72 THEN S0SU& 829 ; HHCL>*LEFTt<St, 32> ELSE HtKCLy-B* 

899 OitTO 159 

St9 SOOWPiSfl. 14. &QT0 150 

820 PRINT PRINT' » TRUNCATION <C * ■ SQUN&180, 20 

SJtf Pf!lHT03S2r 5 TfllNti* hi 5,- •> 

8*9 Jfertfflw 



Box spin 

W Meadowcrofl, 
High Crompton, 
Ofdham. 



Tin F.X<;hI.I.HN1 graphics capabilities of the 
48 K Lynx are demonstrated by this program* 
which draws the visible sides of a rotating 3-D 
bos. If lines 230, 250, 270 and 290 are omitted, 



then a skeleton frame of the box is drawn. If 
line ISO is omitted, geometrical patterns are 
built Up. Here i$ a list Of the variables. 

A - Maximum width of sides 

B - Maximum width of eods 

T = Angle of turn 

D ~ Current width of srdes 

P = Current width of ends 

% Perspective 
- W ■ Reduction in width of sides 

F - Reductfon in height of ends 



100 LETA = 100 




360 DRAM 128-D-P+W, 


150 -S+F 


110 LETTB = 25 




370 DRAW 128-D-P+W f 


100+S-F 


120 FOflT = TO 360 STEP 10 


3&0 DRAW 128+D-P-W, 


100--5-F 


130 LETD = A • COS 


ERAD(T)) 


390 D3AW 128+D-P-W, 


150+S+f 


140 LET? = B • SIN (RAD(T)) 


400 ENDPROC 




150 LETS - 2 * P/3 




410 DEFPROC ENDA 




160 LETH = ABS(5/4) 




420 MOVE 128+D-P-W, 


100-S-F 


170 LETF r D/25 




430 DRAW 128+D+P+W, 


10O^S+F 


*80 CLS 




4U0 DRAW 128+D+P+W, 


150+S-F 


190 1M2 




450 DRAW 128+D-P-W, 


150+S+F 


200 MOVE 128,70 




460 DRAW 128+D-P-W, 


100-S-F 


210 DRAW 128,180 




470 ENDPROC 




220 INK? 




480 DEFPROC SIDES 




230 XFP<0 THEN GOTO 


£50 


490 MOVE 128-D+P-W, 


1 0OnhS+F 


2U0 PROC ENDA 




500 DRAW 128+D+P+W, 


100-S+F 


250 IF D-W<H-D THEK GOTO 270 


510 DRAW 128+D+P+W, 


150+S-F 


260 PRQC SIDEA 




520 DRAW 128-D+P-W, 


150-S-F 


270 IF P>0 THEN GOTO 290 


530 DRAW 128-D+P-W, 


10O+S+F 


280 PROC ENDB 




540 ENDPROC 




290 IF D+W>- (D-dO THEH GOTO 310 


550 DEFPROC ENDB 




300 PROC SIDES 




560 MOVE 128-D+p-W, 


10O+S+F 


310 PAUSE 5000 




570 DRAW 128-D-P+W, 


100+S-F 


320 NEXT T 




580 DRAW 128-D-P+W, 


150^&+F 


330 RUN 




590 DRAW 128-D+P-W, 


150-S-F 


340 UEFPR0C SIDEA 




600 DRAW 128-D+P-W, 


1QO+S+F 


350 MOVE 128+D-P-W, 


150+S+F 


610 ENDPROC 





Extra colours 



Patrick Hit!, 
Walsall. 



&&dm 



THIS rROORAM was devised to produce more 
colgurs on [he Dragon J2, It forms colours by 
drawing alternate lines of two colours, [he 
numbers of which are contained in C arid CI. 
This gives about 30 usable background colours 
which will support the usual graphics 
commands. I have used Draw for the alternate 
lines though Line works equally well. 



to ctso 

10 roa A x to 1 

10 PHODE3, 1 SCREEN1 ,k PCLS 

10 FOR C • I TD 4 

SQ FOR Ct - L TO 4 

*0 P - 1 

10 If P . CI « C THEN P ■ P 

1 t 1 IELSEP - P • Cl 
10 FOR J - I. TO 1»< STIP 1 
*C| tSR»,W -BMO." . STJlt tJi 
100 DRAW "C" . STItt (CJ • 

," + STRi (JJ 
I 10 PR AW ^Slltl, - t STfl» i J 
tlB DRAW "Z" t ST«I (Clt + 

t. " • flTftf I J * 1 ) 
lit NEXT J 

140 CIRCLE! 1*4, ?*J , 75 ,P 
ltd Ffi [NT M 21 .?«} ,P,P 
170 FOR JC . | TO 10 DO NEXT K 
ltd FCLS1 
I»P NEIT Cl 
100 ME IT C 
llfl NEXT A 



ec 



* i ) 

"HIS 



152 YOUR COM PUT£ R, APftIL 19B3 



NOW . . . FOR ZX SPECTRUM USERS EVERYWHERE 

ULLER BOX ... 



A NEW DIMENSION IN 
SPECTRUM CAPABILITY 

It's easy to see why the ZX Spectrum is outselling all the other small 
colour computers, it really is a marvel of new technology. 
Equally marvellous is the new*Fuller Box" for your Spectrum. 
Sound Quality is improved enormously with the built in Audio 
Amplifier which works with all Spectrum programs. The Sound 
Synthesiser will make any sound you want lo design; explosions, 

laser blasts, trains, birds eta Its based on the popular 
G1 -AY-3-891 2 chip, and is supplied with a demo program. 
Finally, the Joystick Port enables you to use any low-priced 
"Aiari/CommodOre joysticks with your programs. 
The Fuller Box tits neatly on to the back of your ZX Spectrumand does not 
interfere with any peripherals, PRICE {INC. VAT) 

including the new Spectrum microdrives. aaq ftc , « -* -v 

But the story doesn't end there! The Fuller Box has been designed to perform many other functions, 
and extra expanded versions are already available. 

Fuller Sound Amplifier Box, including 

Audio AmpEifier (non-expandable) pg Q e: . gQ_ _«, _ 

Fuller Orator upgrade kit - ««-«i> 

to f i M n side Fu 1 1 er Box ;p O 4 Q*^ I postag e f ree, does .not 

X. £.*-¥. UOfine. vati include Fuller box) 

Fuller 'Master Unit^ including Orator, synthesiser, 
amplifier and Joystick port in Fuller Box 

£54.95 + 80 p p&p (Inc. VAT) 




The Fuller Orator An amazing 

Speech Synthesiser which can be programmed 
to say anything you command, using the 
keyboard or demo cassette. It uses the 
Gl SP0256 AL voice synthesiser chip; and 
comes complete with the Fuller Sox 



£39.95 +80pp&p 



(Inc, VAT} 




Fuller FD42 System 
NOW FOR ZX81 or ZX 
-*s . SPECTRUM 



This famous, best selling 
product immediately 
converts your ZX 
Computer into a sturdy, 
"attractive and professional unit 
"with full size typewriter keyboard. A 
tough plastic case encloses the 
keyboard. P.C.B. and power supply It has 
42 keys including all the ZX81 /Spectrum graphic 
characters printed on them. The full travel key switches 
have gold plated contacts and guaranteed life of 10* 
operations. ITS SO EASY TO INSTALL! You simply 
unscrew the ZX PCB from its case screw it to the FD 
case, and plug in the keyboard No soldering or technical 
knowledge required. 

NOW ALL ONE PRICE! £29.95 One VAT] +E2.5Q p*p 
16K Spectrum Expansion Module- to fit into back of 

Fuller case -£24,95 ^ ac - VAT '* P*Pl 

RAM Adaptor Board - enables you to fit 16K Expansion 

Inside Fuller case - £g ,75 (inc. VAT& p&p). 

MICRO 
SYSTEMS 




Fuller FDS Keyboard 
for the ZX81 or 
ZX Spectrum 



Our new advanced keyboard has the same, fine 
specifications as the FD42 system, but with a new, 
re-designed case, space bar and double-sized shift 
and enter keys. A must for the discerning ZX81 or 
Spectrum user. 

SPECIAL LOW PRICE £39.95 (luc vati + E2.SO p&p 



Fuller ZX Spectrum 
Upgrade Pack 



16K Spectrum owners -upgrade to 48 K with a Fuller 
Spectrum Upgrade Pack- Complete vith full assembly 
instructions. Model 2 or 3 only 1 £34,95( Mc . VAT j pAiJ FREE . 



Contact us for a Special Fuller Introductory Pack. 
We are looking for dealers throughout the U.K! 



Please supply the following items: 



n N- 


QUANTITY 


PRIGF 


POSTAGE- 


TOTAL 











































I enclose cheque/p-O- D 

Or. plea&f? debit my Access/Barclaycard No. 

Name 

Address 



Mail to: FULLER MICRO SYSTEMS, 

The ZX Centre, Sweeting Street Liverpool 2. 

Telephone: 051-236 6109 



Please send me further details, I enclose SAE. D 



YC4B3 



A 



YOUft COMPUTER. APWL 1983 153 






z 1 



am 



©oat? ®G\[m] 



■ 



Turn your programs into gold — with Virgin Canwi, a new computer 
software company, port of the Virgin Croup and backed by all its 

resources- Our expertise is in marketing, merchandising and sales - in fact in all the 
aspects of turning software into cash. 

So, we are searching for exciting, entertaining and original programs 
(front software houses or individual programmers) for the following 
home computers — Atari, BBC, Commodore 64 and VIC 20, Dragon, 
ORIC 1, Sinclair ZX Spectrum and Texas Instruments 99/4 A. 

If you have written a games program with good graphics, tots of action and an original 
concept and you want to be rich and famous - but you don't have the resources to 
market it properly yourself - send a cassette copy to Nick Alexander, Virgin 
Games, 61/63 Portobello Road, London Wll. We will evaluate it and if we 
believe that it has good commercial potential, we will offer you a contract for it. 

We are also forming a team of first-class free-lance machine code 
programmers- If you are interested drop us a line with an example of 
your work. 

When sending us programs to evaluate, make sure that you enclose 
your name, full address and phone number, operating instructions and 
details of the computer it runs on. Mjke sure you keep a copy of the program 
yourself. 

We will only be taking on a limited number of programs so don't delay! 



*i 



**f* 



'ff« 



?■■»■* 



tltf 



*Ha 



*Ca 



•fifcte 



**t, 



^ 



>*. 



4b 



4 ^t 



*o, 



'**3 



$d ^ 



***» 



^7 7 



u 



"T 



*** 



*** 



COMPETITION CORNER 



A £15 book token will be awarded to the first correct solution 
drawn from the competition bag. AH entries must be at the 
Your Computer offices by the last working day in April, The 
name of the winner, the solution, and a competition report will 
be published in the June, 1983 issue of Your Computer. 

If you want to set a competition for Competition Corner, 
remember that the simplest solution should be calculable by a 
short program rather than by any other form of reckoning. 



THE PYRAMID 
OF AGPAR 



At THE bottom or ihe Appar Sea lies the 
massive millennia-old Globe Pyramid — a 
structure bristling with solar^powered 
defences, but which contains the test 
remaining matrix-stones — just what you need 
to (deport off Agpar before it is swallowed up 
by the black hole which has all but consumed 
Ag par's twin suns. There will be only 24 
hours to gather as many stones as you can after 
the suns arc finally extinguished, turning oiT 
the Pyramid's defences* You can only pray 
that you can gather enough! 

The Globe Pyramid is a tetrahedron in 
shape — a pile of 35 globes on a triangular 
base, five roan utlre . E&< ":; globe is coffliet i ed 
to its immediate neighbours via a closed tube, 
and one stone is to be found at each end of 
each tube. Once inside a globe, yon can gather 
all the stones from the ends of the tubes 
leading into it: but it takes an hour to break 
through a tube, and six hours to break into a 
globe from the outside. How many stones can 
you get? 

Competition 
results 

THERE WAS a large number of entries for 
February's competition to win a Commodore 
64 — but no obvious winner. The sentence to 
be completed was: "a Commodore 64 allows 
me to do so much more . . .". Many entries 
called for musical accompaniment: "I'll snll 
need it. I'll si ill feed it, when I'm sixty four" 
was M Clark's version of the Beatles lyric. E 



BY ANTHONY 
ROBERTS 




Cross adapted the song sShcnandoah to give us 
"O Commodore, 1 long to hear you, rock on 
you rolling micro". 

Other entries were more jokey — like A 
Stewart's "My wife said she would leave me it 
I got one"; j Finnigan said "It's got more 



Solution to the 
February 
crossword which 
offered a 
Commodore 64 
9S the prize. 



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bytes Mian a ship's cat hosting a flea 
convention' 5 . Rob Munday was refreshingly 
direct with "Reasons] Why do you always 
want reasons! Juss send the computer" while 
the Rev D TordofT made the special plea thai 
"VlCars need much bigger memories — 
without the temptation of Apples". 

The 64 f s relation to the rest of the 
Commodore family was a common theme. P 
Farcy confided "A Per can be so restricting, 
don't you think?" and Y Birch suggested that 
"It's 64 of one and half a cousin of a Pet". 

These were all in the running but after 
much deliberation we awarded ihe prize to W 
Bellini. 27 Edgecombe Park Drive, 
Crowthorne, Berkshire- who turned the 
sentence into a near-limerick with "colourful 
sprites, and sound (hat delights keep programs 
from being a bote". 

The solution to the Orb Bomb Puzzle was 
that shree twists were the minimum number 
required to defuse the bomb, A Scott, 55 
Huntley Grove, Peterborough, PEl 2QW, did 
not supply a program solution but explained 
i hut it was much easier to consider the bomb 
as a two-by-two by two Rubik's cube. Several 
other entries took the same approach. | 



VOUfi COMPUTER. APRIL 1983 155 



t 



INTEREST 



CREDIT 
NOW! ON; 





If your order contains over £120 worth of computer 
hardware apply now for interest free credit by telephoning: 
Mail-order: (0702) 5529 11. London Shop: 01-748 0926. 
Birmingham Shop: 021 -356 7292. Southend Shop; 0702 
554000 or write to PO Box 3, Rayleigh, Essex SS6 SLR. 

You pay 10% down, then 10% per month for a further 
nine months (to nearest penny). Example: Atari 400 48K, 
Cash price £299. Credit terms: £29 90 down, then £29.90 
per month for nine months. Total £299, Credit quotations 
on request. This offer subject to approval which can take up 
to 48 hours. 



THE NEW COMMODORE 64 

The incredible new computer from Commodore comes 
with 64K RAM fitted! Plus 16 colours hi-res graphics, 
320 x 200 pixels. 40 columns by 25 lines, Z80 micro 
processor can be added — that means you can run CP/M 
software, 8 independently movable Sprites with collision 
detection, and a sound generator with 3 voices, 4 wave- 
forms, envelope and filter to rival some dedicated music 
synthesisers. And all this at the most incredible price ever 

{AF56L, Only £33900 



DRAGON 32 




The amazing new British computer 
with a full-travel standard keyboard, 
a 1 6 bn microprocessor, 32K RAM 
fitted (expandable to 64K and later to 
25b*K!l|, 9 colours, hi-res graphics 
and Microsoft extended colour 
BASIC (the very best BASIC to learn 
with). It can be used with virtually 
any ordinary cassette recorder, it has 
a printer interface (Centronics-type), 
joysticks are available and it's in- 
credible value for money. 
(AF57M) Only £199,50. 

Lots of r\ew Dragon software 
available. 



THE AMAZING ATARI COMPUTERS 



4 Consoles Available; 

Atari 400, 16K RAM (AF36PJ £199 95 
Atari 400. 48K RAM (AF37S) £249 00 
Atari 300, 1 6K RAM (AF02C) £399-00 
Atari BOO, 4BK RAM (AF65K) £440. 00 

* All above with BASIC & handbooks 
Carriage free, delivery next day 
by Data post 



Olh«r hardware. 
Co55<3lle Recorder 
Disk Drive 
Thermal Prim or 
Epson MX80T Mk HI 
Epson MX80F T Mk III 
Pnnic» interface lor 400 
Primer Interface lor BOO 
Interface Modulo 

VerSdwfUfr 

1 6K RAM Module 

4SK RAM Module for 400 (AM4X| 

48K Upgrade 1m 400 (AF4$Y| 

Floppy Otsk (YX87UI 

Lfl Stick (AC45t*| 

Joyslitk Controllers (Pair) <AC37S| 
Paddle Controllers (Pair] (AC30HI 



(AF2BF> £5OO0 
{AF06Q £2 99- 95 
IAFQ4E) £ 199 95 
|AF38R, £399.95 
[AF40TJ £447 35 
(AF41UJ £59 95 




'AF42V) 

(AF29G) 

<AF43W) 

(AfCttJ) 



£59.95 

f 1 35.00 

£ 199 95 

£55 00 

£99 95 

£75.00 

£2 50 

£24 95 

£13.95 

£13 95 



mill iinH',;i.imn 



Q «ws 




Per lull rinli.li «■ fOr qui hmtdwaie loallal iXH54J| S At ippinf mliKl 

JOIN THE UK. ATARI COMPUTER OWNERS' ClUB 

An independent inan proup Fi>ur r»ti«f pi thq club macjjjiiri* lot only £ 3 00' AddreM yput tubfejipnprv ig ftocfi 

Hint 1 Hi in* club m*ijjMin* ie*rur*a a lucofitl on cfi ni stie r i« rs0s1 1 n won end canioiriBd * CtiUaeiiorl ot at ma nsif aiion and 

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sek«c1ion oi mcmblit contribution* to I no prorjrairi !b»*ry find much more 



THE FINEST SELECTION OF ATARI SOFTWARE 



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THE NEW 

MAPSOFH" CATALOGUE 

48 fuIJ colour pages of Atari. Dragon 

and VIC 20 hardware and software. 

A comprehensive guide to whafs 
available. Price f 1 
THE NEW 

MAPLIN CATALOGUE 
contains full details of all the 
computers and most of the software 
shown here and much more. On 
sale now tn all branches of W.H. 
Smith price £1 25. Or send £1 .50 to 
P.O Sox 3. Hayleigh. Essex 



V1C20 COLOUR COMPUTER 




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Ma pi in Electronic Supplies Ltd., P.O. Box 3, Rayieigh. 
Essex. Tel: Southend (0702) 552911/5541 55. 

Oamonslrofion*, si Our shops NOW. Sde the compimrrs in arlian .it 
159 161 King St,. Hammeramith W6 Tel: 01-743 0926 
264 London Rend, VVn-ucliff-on Sea, Eihk. T*l: [07021554000 
Lvrnon Square, Parry Barr, Birmingham: Tel: (021) 356 7292. 






YOUR COMPUTE!*. APRfl. 1983 157 




ZX KEYBOARD FOR USE WITH 80/81 SPECTRUM 

Our new cased keyboard has 52 keys, 12 of these are used for the numeric pad. The numeric pad offers some useful features, you can cursor with 
one hand and it will be a boon for anyone who enters a tot of numeric data, The pad is a repeat of the I -9 keys plus it has a fuif stop and a shift key. The 
numer jc pad keys are coloured in fed. the norma I keyboard keys, are grey, with the case being black which makes the whole thing very attractive. The 
case measures IS x 9 x 2 Vt The computer (either 80/81 or spectrum} fits nearly inside. You will have to remove the computer from its original case. Jt is 
tho i screwed to the base of the case The case had ail the bosses already fitted and the screw notes are marked. Also fined inside the case isa mother 
board \&\ model only) which allows l&K, 32K and 64K to be fitted m the case All the connections are at the rear of the case i.e. Power. Mc Ear, T.V. 
and the expansion pon. The case is large enough for other add cms also 
to oe fitted inside. One of these could be the power supply, then you 
could very quickly fit a mains switch, or a switch on the 9V fine This 
means you have a very smart self-contained unit This case does not 
stop you from using any other add-ons that you may have eg Printer 
etc. We are convinced that this is the best keyboard avarfabie at 
present Ft offers more keys and features than any other keyboard in its 
price range 



NOTE 

I ne case tan be purchased separately with the keyboard aperture 
ur K.ut so if you have one Of our early uncased keyboards, or m fact any 
Othei itipptfefs' keyboards, these could be fitted The keyboard is 
com lied to your computer by a nboon cabieandthisnas connectors 
fitted ,vnich amply push into Ihe Snclair connectors. Jt is a simple two 
minute job and requires no electronic skills Thrs keyboard does not 
need any soldering . Please specify on order whetheryou require the ZX 
81 or Spectrum case 



SPECTRUM MODEL 

Ths is supplied with spectrum legends and a sightly different base 
for fitting the spectrum msde again ail the connectors are at the rear of 
the case and there is plenty of room for the power supply fand other 
add-ons} Should you want to change, we can suppV both the 
Spectrum legends and details of updating your case which will enable 
i tiodifitawn from theZX 81 to spectrum PLEASE specify on your order 
whether you require the IX 81 or spectrumcase. 




KEYBOARD 
(SPECTRUM/81) 




r«si 



B 



Trmnrnr 



Internal fixing for 
ZX 81 keyboard case. 



r ■ ■ i 

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Internal fixing for 
spectrum keyboard 
case. 



SPECTRUM LIGHT PEN 



The oen eriabies 
you to produce high 

resolution drawings 
on your own televi- 
sion set. saving a vast 
amount of time over 
using basic program- 
ming statements, such 
as Plot. Draw etc. Vou 
can erase, modrfy and 
save drawings and it 
comes complete with 
software program. 
The superb light pen is 
available from d.k. i 
tronics, 




£19.95 



16K Memory 
The I6K uses' 
Static Ram at\ 
using the Stati 
speed tow pen 
the computer 
which comes 
where. Positic 

64K Memorj 

All the above 
advantage lie: 
56K of usable 
the use of oth 
8192*65536 T 
Spectrum Mi 
Upgrade your 
it is simply slip, 
are supplied, ; 
time. The fitfir 
same as Sine ic 



168 YOUR COMPUTER. APRIL 1983 



ZX 80-81 Spectrum 

HARDWARE 



SPECTRUM/81 TOOLKIT 

I his is the toolkit which won acclaim m the feature in the August 
1^82 issue f pages 29 and 30} of Snc^r User "ft is the most impressive 
program, fast m execution with clear and fun instructions, M. stands out 
from the rest of the field ,." The 2XED is a powerful editor for use on the 
expanded 2X81 It is intended for use by the senous BASIC programmer 
and offers several useful and time saving features most helpful during all 
stages of program development The facilities provided are as follows 
ALTER. BYTES, COPY, DELETE. FM>. HELP, INSERT, KEEP. MOVE. 
RENUMBER AMD VERIFY The Spectrum Toolkit contains most of the 
features above plus autoi-ne numberer and append, and will run m the 

1GK and 48K spectrum. 




Both at 
only £6.95 



FLEXIBLE 

RIBBON 

CONNECTOR 

If you have ever had whiteouts 
or system crashes this could be 
the answer, ft stops tine move- 
ment between me computer and 
the RAM expansion, it is supplied 
with a ribbon, 6 inches long, with 
a male connector at one end and 
a female at the other, at only 



JM MEMORY 



: - 



rslon £22.95 

amic Ram Chips. We use the dynamic as they are much denser than 
ess space They are also much cheaper than the equivalent product 
he Ram is manufactured with high quafrty materials, and uses high 
p*s it is luppfied ready-built and only needs to oe plugged into the rear of 
e components art feted into holders. This massive add-on memory 
Sully assembled and tested is the cheapest 1 6K memory available any- 
iemory from 16384 to 32768 (Same as the Sinclair memory,] 

T6K (UNCASED) £19.95 
rsion £52.95 

■oon on the I6K also applies to the 64K Memory Expansion, but the 
J64K giving nearly FOUR times the memory. This advanced model has 
y in addition, the bfocfc from SK to 16K can be switched out to enable 
fens. The graphics ROM is to be used m this area Position m Memory: 
be From 8 1 92- 1 6384 is SWUChabfe, 64 K (UN CASED] £49.95 

Expansion £35.00 

m to 48K of user Ram. The Spectrum memory expansion fs simple to lit 
Be the case, and then only requires plugging in Full fitting instructions 
only tool you will need is a screwdriver and just two minutes of your 
res no electronic skills Position in memory from 32766 to 65536 (The 
rade to 46K|. 



4K GRAPHICS ROM £24.95 

The DK Graphic module is our latest ZX 81 accessory. This modufe 
unlike most other accessories fits neatly in side you computer under the 
keyboard. The module come> ready built fuiy tested and complete 
with a 4K graphic ROM This will grve you an unbelievable 448 extra 
pre-programmed graphics, your normal graphic set contains only 64 
This means that you now have 512 graphics and with their inverse 
1024, This now turns the 81 into a very powerful computer with a 
graphic set rarely found on larger more expensive machines In the 
ROM are lower case letters, bombs, Dullets, rockets, tanks a complete 
set Of invaders graphics and that only accounts for about 50 of thei n. 
there are still about 400 left {that may give you an idea as to the scope of 
the new ROM) However, the module does not fmish there, n aisohas a 
spare holder on the board which will accept a further 4K of ROM/RAM. 
This holder ran be fitted with a 1K/2K/RAM and can be used for user 
definable graphics so you can create your own custom character sets 

WHY WAIT? 

ORDER TODAY FOR FAST DELIVERY 



16/64 MEMORY 
FOR ZX 81 



The above iflustrahon shows the casing for the f6K or massive &4K 




I ^j»)tJtrty|»(ifrTiKrwir.'^iftchlKomffl«rnoryfr|f.4uinuy».^plKrwhcnor(]nvi9 

Please send me . . @ £ 



Please send me , 



■■+ ■ 1 * V * T -f F ^£f ^- * -f -I I i ft ,■ El I ■ ■'■«« 



Please send me , , . . @ E 

Please add on E 1 .25 for PtP 

In enclose cheque/P.O payable to OK Tronics total E ■■■■■■.■■.■ 

or debit my Access/Barclaycard | | | | | | j | | | | | [ |~| 



Sjgna:ur* . 
turn* 
Adeem . 






Send toDK Tronic$, 23 Sussex Road, GOrleston, Gt, Yarmouth, Norfolk. 



Tel: Qt. Yarmouth |0493J6024S3 

cK 9 troiiics 



New COlOw frrothuf e new ** HWtfc. icntf SAE for quick r crur n 



VOUR COMPUTER, APfllL 1983 159 



C.J.E. ®&B 

micmcnmputErs 

VA J included wtrere apptrcabte 

QUAUTY OISK DRIVES 

S-rvetoddvaJOuiekufigitMMi * tOO*. £300 00 

Oual*rw*40tr»CW*rtfll9*td«2'Httk £380 00 

Dual fltr.* 40 irsck tiftibto **J*d 2 * 200k ES4S.2S 

Dual drive BO track double *d«l 3 * 4flQk £?W-2S 

Al drives *'# «s*0 with sv»ri PSU (of lafiaWily, 

ana irtdiido co^noctirig cable* and utnil-** fluik, 

Daiivery 14.00 

SOFTWARE FOR THE BBC MICRO 

M>$$[LE CONTROL Ine first irrplc.TiiiriT»lnjp 0*1 she 

BBC Micro of the popular arcade game. I32K). .... £3W 
MAZE MAN an jUTient . v«rvor of the popular 

wodOiam*.. 43ZKI , , £6.00 

BALLOONS * h-goty original garr** thai «w becomes 

compulsive ptevuig(32K 1 . ... K.00 

DISASSEMBLER [ha ramorj dump routine include* 

« tcrcUi-iQ Heck m memory facility. ( 16KJ . . , £5-00 

MISSILE CONTROL MAZE MAN & BALLOONS 
uh (ha Keyboard or Joyiticki for conliul 

30+ PROGRAMS FOR 
THE BBC MICROCOMPUTER 

Th* Soak conunri program btung*, with tuploruiiOTH fcr 

lip* OA M*ing in* B8C Micro 

GAMES UTILITIES GRAPHICS & ML SIC 

Most program! wil run or Model's A & B 

Edited by C.J. Evan*, various Aul*ic*». 

A pdif of CBMOIte* wnih all I've a-ogrem* Is available 

BOOK £5.00 
B0K b CASSETTE SET £9.00 



LEADS 

ihe StK Mkrg H net .'..|i . ...t .1 e*MMt* Md 

7Ptn Dm lo2 > S.Smmfj 1 x l.Smrr miii|»cli* El 00 

7Pm D<rnoSP^it OlnfrJ.Sn-JTiminljBek , MOO 

7PmDirHc.7PiriDiri. .. E4 00 

7Pin Dm PLUGS . , . Two for £0 66 

CP.nDtfi PLUGS {for nG&wrckwJ fwotorECte 

SPin E»l PLUGS (380" tor RS232J. ,. Two<or£0rS 

RS423 TO RS423 18BC V-crt. Id BBC Mtroi 

rwi/ me-tre caffe £4.00 Four rreire ctv* £ 5.00 



TElEVISIONrMQNITQR LEADS 
full range available 

Phono piup Id Co MVnthh.flfmuaiity cable 3 Metres . . 

aNC PIuib to BNC Plug 

8NC PUfl to Pfcoftd ftufl 

li.tr, flSCMitroloReniTfiMrtsriTVHM] , , 



£3.00 

£3 10 

£2 Sfl 



PRINTER CABLES 

BBClo36wty Cfwonici . Tyo* conr«iof , £17.50 

BBC w2SwBvDTv0e {for use roth RS23S} £9.50 

BBC 10 40 war edge Connector I Centronics 7391 . £20.00 

TORCH loaftwfiy Gnnliprclcs Type connecter £20.00 



BLANK C30 COMPUTER CASSETTES 

Ten tor W.50 

16 Wey O Type PK19 with Cover Ct JS 
Computer graphic* design pad* 10O sheets £4.00 



BBC UPGRADE KITS 

RAM UPGRADE I lOOrnJ CQ.Q0 

KIT A Pr-nlr d I/O Pwl .« .. , £9 SO 

KIT IB Analogue. Port £8,00 

KITC Sflfifl I O & RGB £10.00 

KIT D Expansion BuV Tube £7 .60 

Full Upgrade fch ESfl.OO 

Al component* full spec i'icetJon 



STAR DPB460 PRINTER 
FROM £250.00 INC VAT 

80 CPS : S0.-96- 132 COLS 

&IDIRECTINAL LOGIC SEEKING 

TRACTOR WITH FRICTION FEED 

CCMTtIONpCS £217 39* £3261 VAT =£250 90 

RSZ32 £236.00 -C3S 26 VAT = £270 25 

High Res Graoh'C* option to allow BBC St**tn dumps 

Ct&OO/CaDjOO 

I24HR SECURiCQR OELiVERV FOR PfiiNlERE £8.001 

VAT included where applicable 

Send SAE (of full Price Lrtt of our large r«r>oe of accessories. 
POSTAGE Add SOp per order or as statEd 

C.J.E. 

rn: r , rnr , rim , ri . .i DrQ Dopi iyci 2S h£Nhy ave, hustington 

I I Ik LI sJLrLlhlfrJUlCi a W. SUSSEX BN16 2PA (090621 6647 



Battle of Britain 

By Microgame Simulations for the Spectrum 

One dav ' n summer., 1940. Reports are cewfiing in Of eflefTvy 
bomber squadrons crossing the English coast; target unknown. 

How are you to deploy the nine tighter squandrons under your 
command to intercept the incoming threat! 

British and enemy squadron movements are plotted on a superb 
high resolution secreen map of south east England with 
communications signal* presented both visually and in morse 
code. 

Features variable difficulty levels, full control of squadron 
movements. randomFy selected targets and bomber routes for 
each game, intelligence reports, refuelling etc. 

A tense game of strategy for one player. 



48K Strategic 
Wargame 



only £5.95 
(Inc. p&p) 




DRAGON ... BBC B 



If Your Computer says it's good 
. . . what more can we add? 



DEATH S HEAD HOLE p unique idv #ni u»s lo< ihe Oraflof arid &0C B. rtr.iran will 
■n< advice of nave reujue *«cw'li - you'd ilnait believe it's Vim' Hcu»s Of 

en^l>rT«n| trot eiciteroflrft 
Dra^nn BBC S LS 49 

LlONrtEART our rcrnrfic new two -air t graphics adventure for trie Oregon, mtpirca 
bv ffcerard tfve L^nrmari'i TMrd Cruiede to li^e MaJy Lartc. Messes 6" (e*iuie» 
Diagon only ES.4B 

CHAMPIONS! -- Pancv YOuf ehence* es me neki Brian Clougn? This it in« moil 
compicie, realistic anc vngrossing manayemenl same you II find. II you don' • g<vs r «o 
-toots about rupttiii , you I" oc "looked - ■' you do. tOu'K b« u'«v -no *" night 1 Buy and 
ted pijy««a <R-tt(t ihe bank Kapcty. £5tw with c«av*ii luioeneione and E>>« C^ub't 
probleniii. then net your UronaWal leem readv ei each SaturrJay 4pp*0*Chei Fe*iw*l 
wMktv- updafci ol '**£mj* lib'* pramoiiofl end '*ie^jii0.n, aihiwa check* on 
sOoOnrnn' leami n»ni'*r carnal, and mueri, much more Tti.i ■ ihe game mat w* 
Prtry' 

orajpr aac a «.« 

WORDS AND PICTURES 
7 HAWTHORN CRESCENT. BURTON ON TRENT 



f ASV ORPER CI* in* COuOOft O* **11*ly «M* ytw 
Pfogreme "etui-red en ihe oac* al your cheque. 

>« dKki *e«d 9T RETURN OF POST tor (he 



nam*. aodr*n, ewnputer am 



Q&ra^on 31 □sec B 

QfJeaPv'a Heed H<p* Ql.K>nfiiart Qch*rno>on»' 



Nam*.. 
AddreH.. 



ALL POSTAL CUSTOMERS RECEIVE PERSONAL 
PREVIEW OFFERS ON NEW PROGRAMS 



160 rOUR COMPUTER, APRIL 19S3 



ATTENTION ALL DRAGON OWNERS! 

FED YOUR DRAGON LATELY? 

THEN TEMPT HIS TASTESUOS WITH THE MEATIER MORSELS FROM ActlVe Softw are! 
OUR POLICY* IS 100% CUSTOMER SATISFACTION — TRY US! 

8 CHALLENGING GAMES ON ONE CASSETTE — EACH GAME INCORPORATING THE 

SPECTACULAR FEATURES OF THE DRAGON 32 : 

* BRILLIANT COLOUR* * IMPRESSIVE HI-RES GRAPHICS^ 'EXCITING SOUND EFFECTS* 



1) Interplanetary Trader — 20k+ ! 

The year 2283. Occupation- ■ Space Trader, Tour the Solar 
System In this real time game. Very challenging and 

feature packed 

3) Wumpus Mansion — 20k + [ 

Incredible Fun 1 . 1 . Outwit the Wumpus (if you can..,.) and 
raid the treasures of the Mansion. But don t trigger the 
... — TIME BOMB! — 

5)Hi-Lo — 20k+! 

Is it skill or is H luck?? Turn E50 into £1,000.000 with 
this simple, yet highly entertaining game. Supersound. 
_.. , . Brilliant colour, and graphics. 

7) Atom Hunt 

Full colour, sound, and graphics add to the excitement of 
this addictive game of dedue'iori Features'- 1 to 4 
players: individual scores and ratings. 




2) Execut ion — 20k+ ! 

A hangman style game with a difference. Piay the 
computer or an opponent. lots n» ex! ra features Good 
- graphics and sound. 

4) Wipeout 

Compulsive, exciting, challenging game of fast reaction. 
Begins easy but gets progressively harder. With sound 

and graphics. 

6) Snail Pace 

Announcing: - SNAIL DERBY- '. Supei enter tain mentl 
Computer calculated odds and form. 2 - 8 snails per 
race, Beat the bookie! Full Graphics. 

8) Air Assault 

Blast the skyscrapers with ultra -high explosive bombs 
and dear a space to land your crippled aircraft before 
crashing. Hi -res graphics and sound. 




.rf % * All 8 programs supplied for the realistic price of just: — 
JtSiQ a \#% * All 8 programs double recorded on our own quality tape. 
%0&r I * No- quibble replacement guarantee. * 48 hour dispatch. 

*Hvv\N^Send Chq/PO. tO: Active Software. Temple House, 43-48 New St, Birmingham B2 4LH, 



£5 



75 



•25p 
PS P 



SPECTRUM 
43K 



SPECTRUM 

4SK 



VELNOR'S 
LAIR 

THE MOST REALISTIC ADVENTURE YET 

The buck Wizard Vvinor has rone into hid ins in the 
tidiiim LjbvnnUi o< Hi Elk The reason U nuw plainly 
Clear, alter cciilunus of. searching he ha* finally discover- 
<:d the ancient tomb of Grako and is now about to realise 
his ghastly ambition to become a Irue demon on earth! 
Time is too short to mass an Army ajjnnlst Velnor. There 
la only oat hupi- for mankind, That one brave adventurer 
may be able to penetrate Vl'lhOr"* defenc«, defeating his 
guards. aviotlin£ the traps and surprising Velnor before 
the metamorphosis is complete. You are thai chosen, person, 
but beware, not only docs Velnor employ the most ghastly 
of vtva lures as guards, he it also ■ master of Illusion. 

In this [> & D stye adventure you may be a Wizard, 
Warrior, or Priest, as a Warrior you are best MjiU'il 10 
bRtUe, but how will you eopn with the fiendish spells of 
Velnor ■* As: * Wlrirtl your tpell-s are di'vait Atinj;, but 

be wart, your magic is limited and armed coin bat doesn't 
come easy f As a Kriest you may protect yourself with the 
ilev i no powers and you have no (tar of the undead but 
how will you hiinate tlic ghastly Trails? 

The adventure wilL require ingenuity and careful plan- 
nine Comdat takes the form «( DID style scenarld* where 
inMirn death Is rare hut, beware, wounds are cumulative 
and itratergy is of the utmost importance 

Only £6-50 inc. p + p 

Cheques or P. O. to : 

NEPTUNE COMPUTING (Dept. YC1J 

98, Howe Street, 

Gateshead, Tyne & Wear NES 3PP 



VECTIS 
SOFTWARE 



VECTIS SOFTWARE 
6 Victoria Rd, 

Sandown, 
Isle of Wight 

PQ36 8AP 



AH ' ^ '" '*Y\ 16K 3nd48K FAST ACTION 

WJvSr^^lU MACHINE CODS, 

PONY EXPRESS (froggertvpe game}, Can you cross 1rw/'"~N 
rJaMri ond the rhw Bvokfirw INDIANS WAGON (TRAINS fftfv* 
CANOPS and CROCODILES? Full colour, superb graphics & 
and sound effects. Muhiple skill levels make this a very '_ — 
addictive game, C4.95 

VEC-MAN Superb all colour machine code version of this 
popular game, £"4.95 /T\ 

TV Crmrtnim FAST ACTION by KEN TlNDELL 
*-J\ ^/CULTUm fbm Cup Winner for 3.5K machines. 
DEATH MAZE OF MANDRAGON drfficull 

and addictive, not For I he Faint hearted. £4.95 

FURTHER MAZE MODULES lor the above. 

£4,95 

ASTRO DODGER and SNAKE can. you avoid 

trouble whilst surveying Magron IV? How many 

numbers can your sn^ko swallow? 2 addictive 

games. £4.95 

EDUCATIONAL TAPES for ZX SPECTRUM and 
VIC 20 , . . 3K. 8K and 16K. 
CHEMISTRY TEST helps to revise 0* level 
chemistry. Pleass state which computer when 
ordering. £3.95. 

(MMEDIA TE DESPA TCH 

Alt ptrces include post ami psckiftg, 

QuaAry products from VECTIS SOFTWARE 



VOUR COMPUTER. APHU 1983 161 



HAVE YOU GOT A BBC MICRO? 

THEN YOU NEED: 




WE WON'T TRY TO PUSH LASLKBLG ON YOU LIKE THE OTHERS - SEND OFF FOR 
A SAMPLE COPY AND YOU'LL FIND THAT LASERBUG SELLS ITSELF 



ILARLE. . . BBC DUST COVERS AVAILABLE . . . BBC DUST COVERS AVAILABLE . . . BBC DUST GOV 

Specially made LASKKBL'U Dust Coven available for only £5.25 inclusive. Made: of high quality polyester col ton which is better than the less 
attractive PVC ones. Ami-static and in a complimentary colour, Vse the form at the bottom to order. 

ERS AVAILABLE . . . BBC DUST COVERS A VA1LABLE . . . BBC DUST COVERS A VAILABLE . . . BBC 



1'lcase supply mc with: A sample copy of LASERBl ti ■<• £1.00 

A 12 Month subscription to 1-AShRHUCr fa £12,00 tor 12 i»ue* oJ the magazine 

A 6 Month subscription to LASERBUG « £6.00 for 6 issues of the magazine 

An overseas subscription to LASERBUG <fl £14,00 (Surface Mail - write for details of air mail) 

LASERBUG IXm Cuvcrf*) @ £325 each 

I enclose a cheque ['O lor £,....*.... . made payable to LASERBUG 

NAME ADDRESS 



Please send the completed: form to: LASERBUG Dept YC, 10 Dawley Ride, Colnbrook, Slough- Berks., SL3 OQll 




COMPUSENSE LTD 

Computer Systems Consultants 

286D Green Lanes, PO Box 169 
Palmers Green, London N13 5XA 
Telephone: 01-882 0681^6936 



DRAGON and 
TANDY COLOR software 

1 r»FMC)NMjchirn-CutloMar)Hor COIOH LWAHOrv cartridQ* C 18.95 
A con ' -r ifiietmg nuehitu; iMr pit»yi.niii At rovituKH' in PouuUsi 

, V'i if r-. "Easy to i*wr >t irtflM tiwji 

pfKCtl thm f« T.|.ii] T ColtM i)*no» on vueir 

2 D€C0« M«»fcni CO* COLOfl DRAGOIV «.uMi«haw t IB.aO 

Tr^is. cj>tr-drj4> cowM uvc >du j wui talur*." 1 OtCOtS' !AMQ* COLQH 

BASIC p»o*am-i to ORAQON BASIC mtxt v»c* v«o* Ju»t Iuhmi ,i TAfiDY lap* on vum 
DMAGON. o* a OSA.GON M»on vow TAMDY COlOfl. laid IW DECGDt W Mmwl 

■ nlli |h|h (l!lMll B flSC I ■*' . i • ' n i. 1 1>- . .1.-,,. rl ft !. t i> ,M|,..il't Mo« «fl 

OlOB compute" owwj can ukc jJumtinii' uf «■ ititi -«vrv uhauun 
•ftftwanti mrodu<:tu<v p"te 

3 DASH Mdctww Cod* DRAGON t-wl'^grt t ?(f 9& 
A liu* 6809 ,i>>r<Fntifc»i *<k ">■ DHAGO?4 C«npuiw AfurnMv ->i4i#> > i 

in fl AStC ri&rtr and can ba intarnimed w«lh BASK; n*»i«jn»«iii* Ui* BASIC t«i Iwrf 
.. ! leu . <iii n(i Hwcr wrtpt* *nd nu time Willi real ntnq r*>w ctwurMmH 
A too* - -.ii. ''(^1 txuduCI 6n J demamln^ T^^L. 

4 SPACt RACE MkIwm Cud* COLOR ORAGQ.Ni . jr 1 rn. c I 1 S $!> 

C**Hitli. ! / 9S 
Acliof> dpc*ikI *"t»tf» (|jhih- QWM jpuurd the irae* [V*i«j', ••"! hptria* fll (tllena 
VHttCfl cjul 'ii' Ihf i»pt«.V Uuit k.e» bcj'd V Joy*lld«* . ! b Hf il'V kn'rii htgh n-vjlulioii 

giatDwci, whim*) AtKiicuv* 1 

5 C TREK BASIC COtOR DRAGON caiiclt" C7.S5 
Si,in.'r HUM j<lv«i*lui* Q»m*. fFJphttb ind Vk^ni 49|ilr«v l^w Klnponi brl-r ■ 

m-«'.ii.Hn' m>M. 

t, DESERT GCH.P0A5IC COLOR DRAGON c««. 

n.ijt. >rMtatiD«i M4p*ay «mO 9690 lw4 *Hih:i» 

I POKtR BASIC COLOR DflAGUH euMHRJI 

, t- •tc-'ii'nl auin - -*! ml iiMj-id. (ruictim* cod« #nit«l fw *p«M) f 
B PIRATES AIIO V 8 ASIC COLOR 0PAGO\ cmuMm 7 95 

An Hnre«lii<c fl*>Mi *olv« l"c pv/f k» I* *'«* * T in* i<a*Hi'* dbc^rbng 

BOOKS 

inve^tNx e&OS A**«mi*j»if PF^inmitg ,10 

pft(. g Mp 

Ault*i*'Ml nni'il^ttf* ><" St*ri-i>.V It fSA. f5C *N- USA. CSC Ik- USA 

lmnxha;r. i>ri{r If or SASfL ^Hth f» I ' ) 9 96 

t>dku *)v »1(-'iT £ S>S VISA & ^fl<^Lh" b» l.'Jrj^'Htf ;,i or fKur 

2-* fv mwfp/ionr •*•**< 






1, GREAT BRITAIN LIMITED 

Vou ate PM awl Chinteltor . Fight 
INFLATION and UNEMPLOYMENT. 
balance the BUDGET and try to Si*v 
POPULAR 

ACORN USSR: Highly enjuyaW. 
ZX COMPUTING: "A eiwltengirkg oame". 
MICRO UPDATE: "A drt-^ril iw 
mraalorTviniacs" , 

f b 95 <xi csssena. 

"A MUST fOR ELECTION YEAH" 



2. INHERITANCE 
A 2 part sjame (teckaO fulJ of features. Try 
to gain you; INHERITANCE m pari I and 
■I buccessfyi takeover iha PARADISE 
COLA Co, in parti. 

PERSONAL COMPUTER WORLD: "Well 
prasarvtad and guo<l .dlutf lot mtHtty". 
C5 36 on CttSMite 



3. THE WORLD TRAVEL 
GAME 

A game tar 1 or 2 jjLiy i-rs . Vout rtttn ri to 

collect 6 sowveniiv iiom around ih* workj 
1'rom Russia to Faixlandsl if* the shortest 
, : itfcta ttnia 

Cop* with HIJACKS. STRIKES. 
THIEVES, CASH SHORTAGES. 
SANKRUPTiCES, BAO WEATHER ETC . 
. . World Man ** fm' irtstiuctions aupptHKl. 
&6C ONLY: i:6,36 tin osteite 



Available from your tocsl computer shop or dtt&ct ham: 

SIMON W HESSEL SOFTWARE, (Dep. YC4) 

16 Lytham Court. Cardwel) Crescent. 
Sunning hi II, Berkshire. Tel: Ascot 25179 



?4 Hour despatch 



1 Year guarantee 



BBC32K 



SP£CTfiUM48K 



' 62 VOUfi COMPUTER, APRIL 19S3 





otect 



store.. 



-itmet angus & 

mOMTJQhTO 



GttQOveQfGR 
S&OOHG 




MicroBase. Fits your computer 
into your home. With style. 

MicroBase. Crafted in solid mahogany, hand polished and superb quality. 
Complete with fit ted nylon dustc eve r to su 1 1 T V s with up to 14 screens. 
MicroBase suits most tompulers - Sinclair. BBC. Atom. ViC.Qr it, Dragon. Lynx, 
etc,, plus room for accessories. Price C20. postage £2. VAT included. 



To Order... 

plea$e send your payment to: 
Peter Furlong Products. Unit 5 y, 
South Coast Road Ind. Estate, 
Peacetaucn. E.Sussex QN9 8NA. 
Tel (07914)81637. ACCESS. VISA 
Please state mal<eo1 compuler 



Dealers... 

MicroBase wi I (enhance your 
displays and your profits, 
Check out our special offer . 

Custom display units, supplied . 



GEMINI 
SOFTWARE 

ZX81 (16K) SPECTRUM (48K) 
STARTREK 

Feature* an 8>. 8 Galaxy, Klingons and Slarbascs. short 

and long range scans. Torpedoes and Phase rs r Computer 

etc. 

PLUS Normal or Hyperdhve: choose your speed hut 

watch the energy level. 

Galaxy Map: keep track of where you have been. Also, 

shows whether any Klingons remain there, and where 

the starbases are. 

Visual display of Enterprise's position and movement. 

Visual display of photon torpedo. 

Messages from crew members. 

5 levels of play. And much more. 

Cassette plus full instructions. 

ZX81 £4.95 

Spectrum £5,95 (colour and sound too) 

Sae for other programs, 

Gemini Software 

36 BADMINTON RD. LEICESTER LE4 7RQ. 
TEL (0533) 64915 



a 



a 



Is 

© 
@ 

m 







THE MEW SPECTRUM 

'ADD-ON', 

NOW WITH ADDITIONAL, 
SWITCH-TYPE 
JOYSTICK PORT 



PLUS 

VAT 



COMPLETE your SPECTRUM with our Mulli purpose 
Sound Generatorand Joystick-port Soard 1 ! With one 
low-cost purchase you can obtain the following 
outstanding improvements to your ZX SPECTRUM: 

• THREE CHANNEL sound effects. PROGRAM three 
independent sounds with music, gun shots, 
explosions etc, 

• AMPLIFICATION of (he standard sound output. 

• TWO ports for Potentiometer Joysticks; 

• ONE port for Switch-type Joystick, 

The ADD ON* uses the amazing AY-389 10 SOUND 
Chip, which gives you an enormous range* of sound 
effecis. The output and volume of each channel can 
be separately controlled, with gun shots, explosions, 
drums etc., produced under the "sound envelope'. 
MOST IMPORTANT TO NOTE — the CHIP is 
'processor independent.' This means that sounds can 
continue to be produced without any noticeable 
effect on t h e speed of y ou r program I f 
The 'ADD-ON' contains its own speaker and amplifier 
ch i p a n d i s suppl ted with a cassette conta i n in a, sound 
demonstration routines and some sample sounds. 
The ADD-ON' simply plugs straight onto the back of 
your SPECTRUM. No soldering is required. 

COMPLETE YOUR SPECTRUM NOW! 



si 



O 




Q 



© 






□ 



JOYSTICKS (POTENTIOMETER TYPE) 

KIT (ind. case) each £5 35 - VAT BUILT e*ch £6,75 

COWBOY SHOOTOUT 

(Machine CodtrJ £3,95 + VAT 
Full feature, TWO PLAYER, cowboy shooting 
game Hid 1 * behind the cad us plants and mcjvi rig 
chuck wagons until theyaff? shoi away Shod 
your opponent and avoid getting hit yourself 
The second play&r can be the computer, but 
you set its skill from 10 levels, Excellent 
colour graphics and sound. 

CABMAN 1 Machine Code) £3,95 * VAT 

You are the owner of a fleet of yd I low lax is. 

A rival firm CQmpf>h»$ with y<pu, try if>y Cu steal 

your fares and run you off the react, ifiheycan. 
Ten skid levels, determine the number at opposing taxis, ih< 
Speed a l which i hey drive and the amount you earn per complete 
|0 u rney . M AX1 MISE your ear n i ng & tiflf ore you lose your nnti re 
IJeet This jytoQiam is first class 





MACHINE CODE PROGRAMMERS - 
ACS SOFTWARE 

ASSEMBLER NOW ONLY £595 

DISASSEMBLE^ NOW ONLY £4.35 

BOOKS 

LARGE RANGE FOR SPECTRUM AND2XB1 




MOTE We sloe* (and markeil PBCGflAVl POWER 
SOFTWARE for lh* 8BC. ACQ UK SPECTRU U and 
QHAG ON HI. Send 1 5.A.E fo' appfopdjte catalogs 



Depl YC4 

a/Sa REGENT STR EEt 

CHAPEL ALLGRTON, 

LEEDS LS7<tP€. 

To: ia«2!6fl31flboi6SS343 



■J All progrdrr-s are now available ill aU good dealers or 
dirvclfrom MICRO POWER LTD- 
Pies** add 5Sp 







Q 



WAT at 15" 



wR|-T£vj AfcfY PROGRAMS' 

WE PAY JO*. ROYALTIES 

tCH DHAGOV SPECTRUM 

BBC *»H0GftAMS 



(51 



YOUR COMPUTER. A PHIL t&8 3 163 



ZX81 SPECTRUM DRAGON TANDY BBC 



16K 



16/48 



LEVEL 2 



A/B 



ADVENTURE 

* Over 200 places to explore in ihis machine code game using 
advanced data compression techniques. 

* No random elements — you will need skill, cunning and a 
| sense of humour as you explore caves, forest and castles. 

Evade ruthless pursuers and overcome a hosi of obstacles- 
Multiple word commands and single letter abbreviations. 



AWARI 



* The ancient African game of logic. II lakes 2 minutes to learn | 
the rules but far longer to master the tactics, 

* Select the 'Goat-herd* level of play and It's an addictive game I 
for children <S + ) that exercises their minds — not their laser | 
Tingers. 

* Select the 'Witch-doctor* level and it's a threat to your| 
sanity. We haven't beaten it and we wrote it! 



£1000 IN PRIZES 



FANTASTIC VOYAGE 
(ZX81 16K ONLY) 

This real-time graphics simulation set inside the human body 
was written by a lecturer in anatomy. You are injected into the 
blood stream in your miniature submarine. Navigate the 
arteries, veins and heart to the brain, where a blood clot must 
be destroyed. Features a real vasular map. You will be 
attacked by lymphocytes which must be destroyed using 
arcade game type graphics, Everything you do uses up 
precious energy. Three display formats — a lateral and frontal 
hody scan plus blood vessel name, a close-up scan and a taser- 
sight for fighting lymphocytes. 



** Buy both Awari and Adventure and enter the 'Foiikade 
Challenge' competition. Details with cassette or send SAE. 



FOILKADE LTD 



DEPT. PR 9 

66 LiTTLEDEAN, 

YATE, 

BRISTOL BS17 4UQ 

ALL GAMES £5.95 EACH, 2 FOR £9.95, 3 FOR £BU5 
(ANY MIX> INCLUSIVE. 






MAKE AMAZING SOUND EFFECTS 
WITH YOUR ZX 81 
TIMEX Sinclair 10Q0 
or SPECTRUM 

THE Z0N X 
£25.95 

nc pip &'«'■■■ i 

* Th» JO*J X SOUND UN*T if eomptrfeKy Wf- confined end «c«-**V 
d » tty wd for mt *4ih ihfl ZX 81 . TIME* 5<nel*ir 1000 *nd Spectrum 
C&mpuie*i.. Ii juii pluo* in - rm dismantling; ch loldnnno: 

* MO p*w#r p*e*i. t*H*ri»*. loediOr MMfMlrH," 

* Mpfiua* Wohimt Crjntml on perwl - *rnpt» volume from ts»«( in loud' 








S 1 



Manual Vo*jm» Control on perwl 
speaker 

* SUrKHrcj Sindeir - 18* flempeeli w printer cen be plugged *UoZON 
K S«un£) Unit without »ff«hng n«rm»l tompkit*' »p*r*i>on 

* Hug*, rings of postfue wtindf for Guimi.Muk, Hoi«opi«*v S&-FI. 
Space Invaders, fcapkutms, Gun thoM, Dfoms, Planet. Lnen. 
Organs B*. Tune*, Charts, etc ... or whatever you device' 

* S full qcWimj. U«K 3 Channel lound Chip giving prognrnme Mn*ol 
of pitch, wjluma of ton** irKl na*te*, ill wnli *nvttop« contra* 

* (#*Hy «J*(f To tilting ga.mw 0' prCHr*mrne< YM^S * If* »kTi(*« 
"BASIC'' flinus pr machr'w cod*. 

+ nfo memory addmne used — 1.0. mapped 

FULL iroirucuone wyth many e>fmg<es rjl *nnv u obt»n ertecti end ihe 
P'ogrvwnH. luppiiii, tiriry auw mio d fim»h Mad*. 

*fof*pf 1 «J n Sprttnt™. yev "•«?* <** Sp&ttwm ft'hwwfl ffwtf Order 



Paymenl mly be made bv Ch*fjUS. P.O 
Giro No. JSS 7006 Postal Order at Credit 
Cert 



Eipnri order* :— Bank Cheque 
I citjr national Motwy Drdor U.S. 4 or f 
Sterlwvg 





NEW' SPECTRUM 
16Ki48K - 

VERSION A 
£5.95 *" J* 




ZUCKMAN 

ZX81 (16K) 

*ALL MACHINE COOE 

nolo 

•FOUR INDEPENDENT 

GHOSTS 
•HIGH SCORE 'HALL 

OF FAME' 
♦AUTHENTIC ARCADE 

ACTION 
*TITLE/DISPLAY 

MODE 
ONLY £595 INC. P&P 



FROGGY 

ZX81 C16K) 

♦MOVING CARS, 

LOGS, TURTLES 
•ALLIGATORS, 

DIVING TURTLES 
•FOUR 'SCREENS' OF 

ACTION 
*AIL ARCADE 

FEATURES 
•ENTIRELY MACHINE 

CODE 
ONLY £5.95 INC. P&P 



rf 



# DRAGON 32 SOFTWARE *h *** 



MISSILE COMMAND ONLY £5.95 

FULL HIGH-RESOLUTION COLOUR GRAPHICS + SOUND 

GRAPHICS DEMONSTRATOR ONLY £5.95 

LEARN THE SECRETS OF HI-RES GRAPHICS PROGRAMMING 



DJL SOFTWARE 

DEPT YC, 9 TWEED CLOSE, SWINDON, 
WILTS SN2 3PU 



TRADE ENQUIRIES WFLCOM£ 



I 



164 YOUR COMPUTER. APRIL 1903 




II 



onwr 
ware 



rf^BB^d 



DRAGON AND BBC MODEL B' SOFTWARE 



A Window on Another World 



DRAGON 32 SOFTWARE 

DRAGON-TREK . . . £9,95 WIZARD WAR . . , 
GOLF . . . £7.95 GRAND PRIX , . . £7.95 
GAMES COMPENDIUM Dl . . . £7.95 
VULCAN NOUGHTS AND CROSSES - , , £7.95 
STAR FIGHTER . . . £7.95 



BBC MODEL 'B' SOFTWARE 

£7,95 DRAGON RIDER . . , £7.95 TANKS . . 
GAMES COMPENDIUM . . . £6.95 
EDG GRAPHICS PACKAGE . . - E24.95 



C7.95 



Send SAE for catalogue of our full range of Dragon and BBC model B software. 

Cheques or postal orders payable to Salamander Software, 

27 Ditchling Rise, Brighton, East Sussex BN1 40L. Tel: 0273 771942. 

Please add 50 pence P & P to all orders. 

Dealer enquiries welcome, Programers wanted: Good royalties paid. 





Installed in 3 easy steps . * , 

1 . Pee) of the touch sensitive key p"wj. 

2. Plug in rClik-Keyboard {no sobering) and place in position. 

3. Apply self adhesive two-colour legends to the keys. 
This full 40 key keyboard has a positive click feel as the keys are 
depressed but as it replaces the original touch pad it becomes a 
permanent part of the ZX8 1 without bulky boxes or trailing wires 

HEmpsron 

"^ MICRO " ELECTRONICS 

Dept vcj . ISOa Bedford Road, Kempston, Bedford MK42 8BL 



LEON] [NOEL 



CIO COMPUTER 



ZTEN CASSETTES PLUS LIBRARY BOXES, 
SELF ADHESIVE CASSETTE LABELS, fr 

LIBRARY BOX INDEX INSERTS £5.50 

3 20 SELF ADHESIVE CASSETTE LABELS £0.90 
Z50 LIBRARY BOX INDEX INSERTS £0.90 

ZX81 16K SOFTWARE 

ZHANGMAN £3.00 

With this educational flame your computer will have 150 words 
to choose from 

PONTOON £3,00 

See you get your computer to own you money, not easy, but 
it can be done 

BANK ROBBER £3.00 

See how much money you can accumulate before you're 
caught and sent to jail 

CASSETTE COVER £3.00 

Put your ZX printer to work and make your program collection 

look impressive 
ZANYTWO PROGRAMS ON ONE TAPE £5.00 
"ALL FOUR PROGRAMMES ON TWO TAPE'S 

£8.00 

Mail order* only - please make cheque/ PO payable to: 

LEON - NOEL 

24 Dudgeon Drive, Littlemore 

Oxford, OX4 4QL 

AH prieas include P&P. UK only 



YOUR COMPUTER. APRIL 1983 18S 




618-95 

INC. Pa P AND V.AT, 



FORTH FOR 
THE DRAGON 32 



'DRAGON FORTH' is implementation of Fig. FORTH for the 'DRAGON 32" 
microcomputer but with a difference. 

As well as the enormous power of the FORTH language DRAG ONI FORTH" can also 
execute &ASIC statements. This combines the superb DRAGON sound, graphics and 
Floating-Point commands with the tremendous speed of FORTH to produce an unparaLtaled 
hybrid. You can write a whole program In BASIC or a whole program in FORTH or any 
mixture of boltt. 



If not already convinced send £2.50 for the 60-page manual (redeemable against first order). 



DRAGONFORTH' is professionally packaged, sensibly priced, guaranteed for life and will 
be despatched by return complete with free demonstration graphics program. 



AUTHORS' Oasis Software will market high quality programs you write in DRAGONFORTH'. 
We pay a lump sum on acceptance and a generous royalty, Let's hear from you! 
OASIS SOFTWARE, LOWER NORTH STREET, CHEDDAR, 
SOMERSET. Telephone 0934515266, 



DEALER ENQUIRIES WELCOME 



a 



ACCESS ORDERS 
TAKEN BY PHONG 
24 HOURS A DAY 



SB 




THE VERY BEST IN MACHINE CODE 



All tir<fi/ijtuj itijifihetl ttttt/tifc ttftittii'ti jittl titjiftvl 

1st citiSi tty trturir friLtt irrctirth' VA T jmf ixnUn/c 

within Europe, SAE 'tit Hit! Int. 



•\ /f~ ff*~\r~Y^\(~ tn "'■»" fc* return rV«W 

)yblt5 1 lb Hrttti 

roHSKSpec,^ m ASTERFI LE 



.TlfliJl 1-/1V1 1 LJUj lxi(.neii dometlie filing 

and reporting system So flexible that ii is equally uiable (ardour mailiriq lisU, 

tajalogues, stock controt, text extracts applications ace endl«s Fully utt-t 

d*lir>ed tints and report display formate, dynamic tjruiltte lenglri hie, records 
and daU ilem*. Fully menu driven with powerful JCa*ers facilities, SO' ling, luul 
average, update, multiple independent Piluy pfinting V«, we a»n in jupimn 
rnicrodnyp when Uncle deliwifi. Nearly all the BK w* ul* it machine Cod*, to 
you gel 32 S per file ComM with example hit.- and 22 fUfjc manual Clb.00 



'WC^MiisttTi'ik-K) 



'"■ *V XT ACtOUC/i 11 IV II ■ (or t6K Sprcirum owners 

Vr« hav* produced j wjlrtet version of MASTER FILE called MASTERFlLfc J6. 
It h,n most ol the features, at big MASTERFILE. with 7 predefined report 
for mall and 6 pie-delmed (ield* eg. name, MKJ'ru, etc., and we have found a 
useful 4500 byt« of file tpac* MASTER FILE and MAST t ft FILE lfi are fulfy 
'file- compatible' and will happily process each other's filej, sq that T6K owner* 
who upgrade to 48K can u*c ihfir old life* KtimedinGty. Complete will) 12 page 
manual, priced al CI 2. 00. 
PLEASE REMEMBER TO STATE CLEARLY WHICH VERSION OF 



tor 16K 
Spectrum j 

n ^^""^' * ■"»«» _ « i v .j.i-)i|. o1 iho ' di.itv v.irn'iv 
AiElt 15 mares. 4 chasers laser defence, 9 tirade*, 9 speeds, demo mode, clluitt! 
tit joystick control "An extraordinarily Ljotxt program" ijvb Born Allan Inr 
Popular Cunipulmg Weekly. We Itlink you will wee 1 "j *JS 



WiKZXSI ^J|jM»"3b almost identical «MrC Id GULPMAIM fl /& 

1&64KZXB1 THE FAST ONE .1 the piraeasw to 

MASTER? I L£ and is In ux all over i he world rvow Specification uvery rentier 
to MASTERFILE. EI2.00 



Campbell Systems, DeptjYC}, 
15, Rous Road, Buck hurst Hill, 
Essex. IG9 6BL. England. 
Telephone; 01-504-0589 





From Warp 
Factor Eight 




Liftoff into 

'83 with HI-STAK 

• make i your computing easier. Issuer 
more roheblB less onhausiing and simply 
more enjoyable 

• angles your computer neatly to trie 
correct orgonomic position for thfl mnst 
etficienl kevbonrd operation 

• provides DXirA v^n Illation lp* hoi ZX81 "» 
and Specirums 

• instantly appfiftct. 

• styled for 83. adds that proiatsionel look 
id your set up. 

• precision miecnrjn moulded in quality 
ABS. non scr.itch - non slip base 



ZXS1 

SPECTRUM 

VIC20 

TRS80 

NEW BRAIN 

JUPITER ACE 

Etc. 



Order form. Please send m e H I-STAK setts) (at f 3 95 par 
set). I enclose cheque/P,0. fo i . 



Name 



Address 



Post coda 



To Warp Factor Eight, Dapt, YC, 

6 Pelham Road. Braucjhing, Ware, Herts. SG11 2QU 



166 yOURCOWPUTER APRIL 1983 



r 




M.C. LOTHLORIEN 

a prophecv with hindsight for all SINCLAIR and DRAGON owners 

BEWARE THE IDES OF MARCH! 

ROMAN EMPIRE The prophecv might be a bit lata, but then it did not 
help Julius Caesar anyway! Late or not it is never too late to discover the 
challenge of Roman Empire, our largest selling Spectrum game. It will test 
your generalship as you build your armies, and fight campaigns in your 
attempt to conquer armies in provinces of the Roman Empire. This 
challenging game takes full account of troop morale, fighting efficiencies, 
leadership ability etc. Three levels of play giving many hours of satisfaction. 
You may find you were born a mere 2000 years too latel SPECTRUM 16K 
ZX81 16K, also DRAGON 32. 




TYRANT OF ATHENS 
(Dragon, ZX81 and Spectrum) 

Can you survivs long erwugh to turn Athens 
inio the most feared state in the Mediter- 
ranean? Trfifn troops, build warships, fight 
battles by land and see against hostile 
Greek States and vast Persian Empire, 
Many mors features in this, our beet selling 
game. [Dragon version available). 



SAMURAI WARRIOR 
{Dragon, ZX31 and Spectrum) 

How would you have fared as a Samurai in 
13th Ceniurv .'flpan? Face challenges from 
other Samurai, pivf* skJ to villages and 
resist attacks by groups of marauding 
bandits. ? levels of play, 9 most fascinating 
game Are you a survivor or will you com- 
mit ritual suickte? (Dragon version available! 



PELOPONNESIAN WAR 

(ZX81 and Spectrum) 

Set during the greet war between Athens 
(youl and Sparta. You must us* all yoi>r ™» 
sources of troops, warships and diplomats 
and your struggle to gain the alliance of the 
Other neutral states, before the final battle- 
Three levels of play, instruction* contain 
map of Greere for reference. 



Also available' WARLORD for ZX81 16K and DRAGON set in 13th Century Japan 

All games contain comprehensive playing instructions and they play differently at each level 

(where applicable) and on each occasion. All ZX 81 need 16K Ram All Spectrum will run on 

16 or 48K. PRICES: SPECTRUM £5.50: Zx 81 £4.50: DRAGON £6.95 

ACCESS NUMBER OR CHEQUES AND PC'S PLEASE MADE PAYABLE TO: 

M.C. LOTHORIEN 

Dept YC4, 4 Granby Road, Cheadle Hulme, Cheadle. Cheshire SK8 6LS. 



E5 




NOW AT LAST! 
LOW COST WORDPROCESSING 

(UNDER £500 ON THE DRAGON 32) 

£ I 






DRAGON 32 
£173,48 + VAT 
PROGRAM TAPE & MANUAL PRINTER CABLE 

+ VA T £13,04 + VAT 



MICROLINE 
M80 

PRINTER 
£199.00 + VAT 



TELEPHONE FOR 

* PACKAGE DEAL * 

PRICES 




SINCLAIR SINCLAIR 

ZX81 SPECTRUM 



TELEPHONE FOR 
* CURRENT PRICES * 



COLOUR BBC 

GENIE MICRO 




VIC64 



ORiC 1 



NEW BRAIN 




SEIKOSHA 
GP100 



EPSON RANGE 



5mm 

AMBER 2400 



MAIL O RDER & CREDIT FACILITIES AVAILABLE * LARGE RANGE OF SOFTWARE * 

mEcwpiv cdftiputers 

141 NEW ROAD, CHATHAM, KENT TEL (0634) 826080/681547 






rOUfl COMPTER APBIL 19S3 167 



THE FLEXIBLE COMPUTER SYSTEM FOR THE FUTURE 




■fid 




mr 



A 





How can Tangerine promise you a 
professional computer tor only L99.95? 
Becaudft, unlike most compute* builders, 
wr> have designed the U LA ourselves. 



This makes the OFBC-1 substantially more 
reliable and versalile to work with and 
what's more, at £99.95, you gel .1 
1 >r r jfessirxtfil system well below the price of 



ORIC-1 



l^^^i l^^^ l |^^ l^^^j [W ] [w 






*- f 



iPkwsu ii'io* 26 days to» de*wwy) Subject to availability 






Order your ORIC-1 direct from the designers 

8Y POST: You can pay by cheque* postal .BY PHONE; Just ring our telesales number 
order. ACCESS - BARCLAYCARO- VISA ELY (0353) 2271 Z2/3/4 



nil leading manufacturers. 

We can give you prompt service, quality, 
reliability and lull technical backup: The 
OftIC Computer System will guarantee you 
that and more; 

• 3 colour graphic display 18 foregrouixi i 8 
background) 

~ 40 character by 28 lint? colour text display 

<High resolution graphics (240/200 pixels) 
240 across screen, 200 down 

• 96 User defined graphics symbols 

• Microsoft BASIC software 

• 6 octaves of music with Hi-Fi output aixa 
4 preset sound effects - Shoot. Explode. 
Ping. Zap 

• Centronics printer interface (compatible 
wilh a whole range of standard prrntersj 

• Optional Communications Modem 
(allowing access to 200.000 pages of 
Prestel and direct link with other computers) 

• Typewriter style keyboard 

• Professionally written user manual by 
well-known computer authors 

• Oric Owner Magazine included with each 
ORIC i purchased 

• Tan- Forth supplied free with every mail 
order 48K Model 

• Extended Basic (BBC etci available soon 

• Full range of business and leisure software 
commg shortly. 



Please delate/complete as apotaabte. 

*l endow a cfteque/p-G payable to TANGERNE 

COMPUTER SYSTEMS LTD For £ 

Piease charge my Access. Barctaycaid. Visa No, 



Name 



Itetn 



Address 



QWC-1 16KRAM 



[ Qty j Price InC- VAT 



ORKM 48KRAM 



OWC Communications Modem 



It yoa require a VAT n*ee*p(pteaM tick Q Ptea** send me a M colour brochure □ 

TANGERtNE COMPUTER SYSTEMS LTD. 3 ClubMews, By Camta CB7 4NW 



ORIC Owner Magazine f Bt-montfriy i 



Postage and packing 



£9996 



£16995 



| E79O0 



| E10JOO 



Total 



| £595 



TOTAL £ 



South London's Largest 
Micro Computer 
Centre 




VIC Cassette £44.00 
Vf C Printe r £229.00 
VfC 1541 
Disk Drive £299.95 



Vic20 5k £129.95 
21 k £169.95 

includes 5 Free programmes. 

1 6K RAM Pack (Switchabte 

For 3K Programs) £39.95 

16K RAM Pack 

(Expandable To 24KJ £49.95 



Jdear for Commodore computers 

Seikosfia GPTOQ VC Printer £239.95 

Commodore 64 Software KJow in Stock 

Main Commodore Dealer for 

New 500 series. New 700 series Business Computers. 



Programmer Kit £39.90 
48k Up Grade for Atari 400 £73.50 
Atari 800 1 6K inc Atari 4T Cassette £49.00 

basic £399.00 Atari 810 Disk 

Atari 800 48K inc Drive £299.00 

basic £469.95 Atari 822 Printer £199.95 



dja 



Plus Daisy Wheel and Dot Matrix printers 
for the Atari range From £99.95 



Atari 400 Typewriter keyboard. Direct easy 
replacement for standard keyboard £78.95 



New Vic Software 

Kruy KongJ 

Dodge Kong s barren's as you 

climb thP stairs 

STDVFC Joysticks £6.99 

Exterminator! 

BFdit the centipede while 

dodging the spider amongst the 

toadstools, Fast action. 

STD VIC. Joysticks 66.99 

Ant f -sp I at t er- matte r I 

Make space rnvaders Jook like 

chi ids play, superb graphics. 

STD VIC. Joysticks £6.99 

VI Ik man 

Choose one to three ghosts. 

STD VfC. Joysticks £6.99 



3-D Man 

Brilliant I You are down in the 
maze like a Pac-Man, dodge the 
ghosts and f mo" your way outl 
Expanded VIC Joystick £9.9S 
Motorway Maniac 
Accelerate towards on-coming 
traffic while dodging from lane 
to Janet 

Expanded VIC Joystick £9.95 
Defender on Trl 
Guide your shjp through the 
maze on 4 different screens, 
Fantastic colour and graphics. 
Expanded VIC Joystick £9.9S 
100's of other programs. 
Send for VIC price List. 



Largest Stocks of Software in South London, 
Available on Cassette, Disk or Cartridge. Massive 
ranges for: ( 

Atari, Spectrum, ZX81, BBC and Dragon. 



Printers 



We carry a wide range of printers Including: 
Amber Dot Matrix £89.95 

SeikoshaGFlOOA £229.95 

Epson MXS0FT3 £189.9 5 

S m ith-Corona Da i sy Wheel £ 549.9 s 

Cables and) Interfaces for most home 
micro's In stock. 



THE AMAZING ORIC - 1 

Colour Computer 

^ * 40 Columns x 28 rows. 
* Microsoft Basic 
* 8 Colours. 
* BuHt-ln Sound 
SynthesJser. 
* High Res Graphics. 

48K Microsoft Basic £169.95 
1 6K Microsoft Basic Phonel 
Come in for a Demonstration. 




Sinclair Spectrum colour comp 



Lfter 



I6K £123,95 

48K £173.95 

We carry massive 
stocks of Software 
for the Spectrum. 



Sinclair 2X8 1 
1 6K RAM 
Printer 



£49.95 
£27.95 
£59.95 




wsc ortve place 



DRAGON 32 £198.951 

Limited stocks available. New software coming in 
all the time. Come fn for a demo or send for our list. 



Over 900 software programmes always in stock. 
We carry probabfy the widest range with 
continuous demonstrations. 



CXpOrt All our hardware and software 
is available Tax-Free to overseas customers, 
please send for our comprehensive list. 



Epson HX-20 plus wide range of software In 
stock now. 



We^n^x^Uentpart 
^youroldmach.ne. 



Change deals or cash 



Maif Order — send for our comprehensive list. 
Ask Access/Bardaycard 

about our mm fi'jiLi' 
Credit Ci^ 
Facilities 




VISION STORE 



3 Eden Walk Precinct, 
Kingston-on-Thames, Surrey. 
Tel: 01-546 S974 'SffiSfiSr 




YQUfl COMPUTER, APRIL 1983 169 



3 GREAT DOTING GAMES 




S£N X" UN Jti Jj written by KtT.r, n™ 
for the ZX Spectrum 

SENTINEL is an entirely original ABC ADE STYLE 

giine, written in MACHINE CODE la give fast action- 
packftdpcrfonTLMic*. The gateway io your galaxy is 
guarded by the Sentinel System Only youi skill and 
initiative stands between the advancing enemy's 
space Dec! and the destruction of the galaxy. Yw 
have 4 space ships per aatvun each armed with 
ph-o'oi.-gajLPQTis and <nuded missiles. Make use of 
the Force Fwsld when ever possible. 



jCIi V Jtaf¥*i7£iK written by Ktrkn ETviui 

• tor the ZX Spectrum ( 1 6 ' 46k RAM I 

• for the ZX8 1 (1 6K RAM) 
FEATURES 

■ ARCADE ACTION 

■ Eight diitef e-rrt typos of luget 
I Rapid maneuvering of aiup. 

■ Qiuck firing of bomb* and luen. 

■ 'Intelligent' *li*n interceptor*, 

■ Realistic bombing txajoeiory. 

■ Confir.Mous display of MISSION TIME, 
SCORE, SHIELD & LAEEH 
TEMPERATURE. 

■ End of mission report 

■ Five lev-els of play. 

■ Pull usees sound effects and colour 



PROTECTOR vrnflen by K*T±n Flyru, 

fortheZXSl(16KRAM) 

P*dtott6i is vrtiHn lr MACHINE CODE ta give an 

arcade rtyle all action ganiff. Using: toe SerstHUj]'* 
laser you mu&1 defend the planet Zuyon boot (h* 
aliens which ue bombing the planets vaai 
insTallation*. On screen Alien score, your mn. 
number of shields left and numbei of I^ser shots. 
Watch out for the Damacles Misfit- 'tihizk may be 
detonated a! the alien Commander's ducrecon. 



Only £5 



Only £5 



Only £5 




Other Abacus Games 



BODYBUILDER; V1C-20 

1 danllctidwwlifltlwtm ««mno« 
pauvj L& muiy daan - so muiy 

Jn™ my he *d my aim . jut Jmt • 



£4.50 



TOR THE DRAGON 32 
»ndVIC-20(16KRAM) 

INTO THE LABTTUKTT: Cat, v>j 
»C4U» (b* eJM Df ihc sfleceres 
553E&TTT 

mti S *ra*auu co «pkn, W 

ac+ecti (q bnd amS miiupik«iJe. 
Vtur-i ■> a j, ujim k. iti* rmrrixc of 
moves tou cat. miic be fore the 
nirMj kllj you. Af lA>ue LJnyi 
la ioffl, SHd chJt one way t> 




> For the Toamjwt 



SPECTRUM GAMES 
PACE 2 

fnHTLTVC 

CucMtic rrarr twioir lh» fan ettdlM 

jfgii. Su iav*U at pkay 

KIU TABLE: 

Dd tout funwqucfctr b*hf* lit* toil 
■_r«wt v-ii-it,* :'*-.'r.,i-,Vui:!;jv 

CANDTMAN 

bee rmui men Uilftiflfi [Ik m*ftTn 

nun A gran m kw t»o pUrm 

TJUCCT 

All lh* ^*n **' the 1*JT 

All fgrnr gamn en ant I'MUlTil 

far j 



ESPZXB1(16KRAMJ 

An uptendon of CNNES SPACE 
L," nei» rt*i*« a huxui uiTT jbgafjon c-1 
wnu uphi £uia5tfnonr PMvpoGn, 
te« JQiiJ iMiufT ind fiiHita - Ml 
■ducuoularnKHVittiW 1 



rortucWi iw* L> IC 




SPECTRUM GAMES 

FACE1 

DErntOTHt: \Mm tots* b**p» o( 

umt mm te hi fan itH n—r iw If 

tube uuiij abrfnmhiyJitt* 

ECEHEXC: S|m ynur HMnrMlW 

tlraa^ tsldHBtoa ptck w? *? p«± 



•nHnv nitkf ih a m m* t e gn veu, 
AltrMflllDfTTIlSCCE:KiKu«lhB 
isrjn faeJmi tberan ^tpp*.i m Um> 



£4.95 



Uloarananx 




rvnCROMUSIC; VIC -£0 

(6WHRRM) 

No cr rratj buw^da* ol Tone 3 
HC«iH>iTte DMdat) ■attnttnae *ftd 

mlocaBccul Tjcoozvzr. CtMt« cr.ua 

H M i d ihf «na Mih aaag jundar 
nauiaaA. A rrn^ tee trw budduij 



£4,50 



ABACUS CONTROLLER 
SAVINC tsfeoBM en own*** 

nsratiriSMiaiffiouiit 

SoaVr osch- s^*vtWB nf SAVE. 
LOADS AMftrvrf**. (Kutttfi*nipWb«r 

EX11 COKTUDLLEK: L4ml« mlch 
«Lik3of, ?! T Alt SAVR, 5U5 » 

LOAD madML Bud m 
^VC30CJi4n«;ipiulcH Icr uufl md 
nlu^a ]Mngjun r-UftWfl tudi eu«nq 

Tncet39S 



£4.95 



WANTED original Machine cod* Program?. 

W« gtutuiM to bmt\*t til eOMi «0*n Wnt* now tat fanJ*f Jr«*iU 



£4.50 



DOMAIN: 

FTdtuthY th» bmi rvnae* of 

XIi b Ji m r«u we "Pf iktif la i 



£4.95 



View bwfoi* buytnrj - Selected j!emj Itoti tiu* advert are available at mofl blanche* of W H SMITH , 
Iht SOTrt* SHOP LONDON and JAY DFX COMMUWCATSONS PORT TALBOT 

MONEY BACK GUARANTEE. CASSETTES DESPATCHED WITHIN 48 HOURS. 
A13 prices incltmive of posp. Send cheque or PO to; 




\^ prog rams 




£ ** 



186 St. Helens Avenue, Swansea, W.Giant. Tel:((M92) 50282 




Abacus Programs 



"Of tit (hr 5 u *fP U, 'i hmtwmiw t 
him i Hlnimid . Iha an* miri 
u n n r tm d rn> and u tlw onh/ of* I 

aJixiD a!win vam' 



170 VOUR COMPUTER. APRIL t983 




DRAGON 32 



Cassettes 



m ZTjf^^^^i — 


1 □ ©© ©© i 



Tango Foxtrot 01 

Using your skiff, locate the airstrip with the radar 
scanner, fly your aircraft through hazardous 
crosswinds and air pockets to land safefy. Watch your 
fuet; watch your artificial horizon; be sure you are 
fevel on final approach. Fult colour, hi-res graphics, 
3D and sound. £6.50 inc. p&p 



HUG 

Air combat and ground strike, "joystick" controlled 

sights cannon fire and bomb release, Full colour 

hi-res graphics 3D and sound £6. SO tnc p&p. 

Fruit 

Compulsive, addictive, fruit machine. Using your skiff 

with the holds, turn your £5 stake into £10 and beat 

the system. Hi-res graphics and sound. £4.95 inc p&p 

Look and Learn 

Educational picture recognition. Hi-res graphics, text 

and colour. Age 3~-1uyrs £4.95 inc p&p 

Pontoon 

Super Hi-res graphics, full colour definition and card 

display Fascinating, absorbing £4.95 mc.p&p. 

DRAGON and ORIC 'JUNIPER'' word processor, 

comprehensive edit facilities, menu and cursor driven 

£25.00 inc.- p&p 



I QUARK DATA P-O . BOX 6 1 , Swindon, Wilts, Tel. (0793) 40661 I 
| Please supply , | 

I I 



I 

| Cheque for total amount enclosed 

■ Name 

■ Address 

I "■■ 




QUALITY 
SOFTWARE 



FOR THE 



^jfc A MICRO 



ROAD RUNNER I OKI £6 SO Cawum*' £9 90 Di*c 

Thw only ful 'nature mathlfweodo K*n*Of> c* the area** cj»™ available f*r tha BBC 

micro 1 . ^Qi1v«* in$[ud»: i^rplling luitfi. ladar rJiiplay, shaeiipoint flao;i. iufl aJtvo*. 

snrjko jcr(i*fij. fi sxi\ tennis, rank ngi, incrsairtig difficulty and aound mtim-tx 

GALA XI AWE |KK) ffl .« Catutta,' £8 90 Dlic 

Fail .niton virimi of fho popular jrcada flarn*. 4 type* at GaLg*i#ri {in 3 irtreu ipwii 

frjrra lions.) swoop down individually or n group* ol rweer (huee. 6shHilnmtj r hr-sco«e. 

-anking*. bonus Iihi t'Sicij ihertiiihfl QiMiduicy. iiiparb graohlciand sound 

CENTI PEDE (WU K 60 Ca**»n*r M. » Qlae 

iTCT-od'bl? a'C»rt* rypa g.m* featuring muirwoomi, H:»j. anatli, jpidprv and th* cent' 

«*du ot touru Exeslliml ertptiict and found & (kill lava!*, hi liera, 'ankirot. 

bomia**, *nd ifiei**»iftfl drtfitulTv H tha ipldwt become mgF* active arm lilt 

rftutftfOOrltS inCIVHf . 

FRUIT MACHINE <32K| £6.50 Caiiette EI.9Q DliC 

Pr'obustr (St tmi! 'ruir macpirta impieinan;atior on the rnarKvti Thuf program h*j ii*B . . 

. HOLD, NUDGf. GAMBLE, moving reel*. raaUtii; frurta and wund iff ecu multiple 

winning lii*». Th.s >g THE fruit machkw proflfaar. to buy. 

Al I E H" F OP V T I J7K I fg W Cmti m (9. » LHn 

a.ifld upon tha arcao* glmt o' ZYGON, bu! our ve«i«n impreivw upon tha original 

arcade name ilietf . You hair* so JJiOOi iSe alien, qui ol tbsir "bcin" tnftHV the "bgqeja" 

fil! up Once- lull, <h* aliem Ny down rolnnttosaiy, tuplod'-n^ a* IrWr hi[ the crownd. 

Suitvabkj fa- u>* emh, Keyboard or [oytilck. 

IrWAOEFIS (SKI tt.60 Canada, £9.90 DJic 

Su&afio' vifaiofi of tne old classic arcade oam« ndudjpg * '*w »i:r« 4ft (lurching 

iivaderi d'oo bomba that frrod* your d#fanc«, and 2 lypw of ipaoeahip f:y over 

refezimg lar^n from&j (hot paTvaswe through vour dSefBrrefls. Hi-icort, ineraajing 

dillifulty. sup«rb lound atfecti and graphic! 

S PACE. FIG H TE fl L32K I IS. GO C >««11< £9 SO One 

Ar;aoa ityla farm Q*K>d upon t«aiu<*t t^am DEFENDER and SCflArUBLE & tvjHt of 

m«natmg ifin fW ft yOu and may nrre-np; to ram you. Separata attack phat«. fu*l 

d-jmpi. tttafotdt, ft»M»t'no; la«tr cannon, imart bombi. hi'icara. ranhjirttt. 5 thin lavtll, 

bunum. 

•WE PAY 26% ROYALTIES FOB MlfJH QUALITY PROQRAMS' 
P'»*i* add &0p per 0^«r 'or p. & 0- * VAT pi 1SW 

" ■ Daalar anquif id mfcom* 



% 



SUPERIOR SOFTWARE 
Dept. YC6 
69 Leeds Road, 
Bramhope, Leeds, 
Tel: 0532 842714 




JOIN THE DRAGON USERS, and 



TAME THAT 




, DRAGON 




Dragon Users pet a monthly publication packed with 
programs, hardware tips and information about the 
Dragon 32. 

Dragon Users will be able to buy high quality software 
produced by our team of professional programmers at 
special discounts. 

Plus a whole lot mof©. 

It eosts £10 to become a Dragon User r which includes 
a subscription to our high quality publication (£20 for 
overseas readers}. 

Make put cheques snd posts! orders fo: 

Co-Operative Computers and Communications Ltd 
20 Wynford House, Wyntord Road. London N 1 9QV 



YUUH COMPUTER MARCH 1963 171 







LV'a 







BUG-BYTE SOFTWARE, MORE THAN A GAM 



All oboufr me was darkness. Tens of thousands 
of screens stared blankly into space. Minds drifted 
aimlessly, dulled by iack of stimulation. The world 
was grey, drab, lacking . , . 

Then suddenly it happened First one, then 
another, then tens, hundreds, thousands of tired 
screens felt a surge of power and flickered back 
into life. They were much as I had seen on my 
own planet's microcomputers — the ZX 8 1 , 
ZX Spectrum, Vic 20, BBC Micro and ORIC-1 . 



The minds paused to take stock, They clustered 
round the screens, their nimble fingers excitedly 
flicking the controls back and forth. At last they 
had found a challenge , . , action and adventure 
with cunning tests of dexterity and reaction. 
Everywhere, conversation was of Asteroids, 
Mazogs, Panic, Another Vic in the Wall. 

Unable to resist, I too had a closer look. There 
before me was vivid colour, high resolution 
graphics. I could practically feel the spine-tingling 











. . . irS A DOOR TO ANOTHER DIMENSION ! 



sound effects as whole battle fleets of Cosmiads 
swarmed out of nowhere and attacked. I should 
have known. As my fingers raced over the 
controls, and f prepared to stand and fight with 
only a single laser bolt for protection, I realised 
I was trapped! 

Too late now, I remembered this was no 
ordinary software I'd been warned, as I now 
warn anyone buying from laskvs, W.H. Smith, 
Currys Micro C, Spectrum and larger 



branches of Boots, and a nationwide network of 
dealers stocking Bug- Byte. Because Bug- Byte is 
more than a game, it's a door to another 
dimension. One that I had opened. 

1 00 The Albany, Old Hall Street, Liverpool L3 3 AB 





rrofcA 







TIMELESS TECHNOLOGY FROM ORIC PRODUCTS I NTE RATIONAL 



16 colours 
professional keyboard 
full graphics 
real sound 

Superb styling 

(Choice of 16K RAM or massive 48K RAM 
I Ercjonomic keyboard with 57 moving keys 
#28 rows x 40 characters high resolution 



COMPUTER SYSTEM 



• Teletext/viewdata compatable graphics 
I 6 octaves of real sound plus Hi-Fi output 
E Cen tronics printer interface and cassette port 

# Comprehensive user manual 



OPTIONAL MODEM OFFERS COMPUTER PHONE; LINK FOR: 
• ELECTRONIC MAIL • TELESOFTWARI • PRESTEL 



99 

incl VAT 



95 



DOMING SOON. TO COMPLETE VCKJR SYSTEM: OR IC MICRO-DRIVE DISCS £ SPEED PRINTER 



FOR HOME: The ORJC-l is the professional alternative lor home computing, 

Superbly styled, the 57 key layout is based upon computers costing many times more; A A 
in the ORICand will help the whole family to learn and understand computing j. 
right from day one. The ORIC incorporates an improved version of Basic 
for ease of programming and use. For the enthusiasts the < < >mpuler has laser ^^ 
zaps, explosions, etc, pre-programmed for games use. with Hi-Fi 
output for incredible effect The communications Modem will 
allow Telesoftware', message sending, and Prestel use. A 

FOR BUSINESS: The ORIC- 1 is the answer to many a ' 
day to day problems. Software is becoming availably for A 4W 
payroll, accounts, stock-control, and many more systems 
to help your day to day business organising and control. 
n addition, the ORIC COMMUNICATIONS MODLM will 
<w you to access up to 200,000 pages of Prestel A 

trmation.to send and receive electronic mail", 
ook hotels, and flights (and pay for them) and to ( 
?ok at the iatest stock-market and share indexes. 

In short the ORIC-1 is a must for all businesses 
rge or small. 

HOW TO ORDER YOUR ORIC-1: By phone: 
ist ring our telesales number Ascot (0990) 27641. 

By past You can pay by cheque, postal order 
ACCESS «ARCLAYCARD - AMEX - DINERS. 
(Please allo^28days for delivery). 



i *( VI K* M ■ 



Tf?im3?iTss 



opyright OMC PffifeXlc r S IN 1 1 RriAllONAL I9&J 



n 



For all home micro-users 
who don't live near one of t he- 
larger city branches of Boots 
or W, H. Smith, and who find 
difficulty in purchasing the 
very latest, best-selling 
software - here is the 
answer! 

Software Express is the 
new, mail-order arm of a £12 
million group of companies. 
We have just signed an 
agreement with 
Bug- Byte, Britain's 
most successful software 
house, to supply their 
exciting products direct to 
you, the user. New and 
original games for the ZX81 . 
Spectrum, BBC Micro. 
VIC 20 and Orie 1 can be 
delict* red to your door 
AT SHOP PRICES. That's 
right, positively no extra 
charges - we even pay the 
postage both ways! 

All you have to do is 
make your selection from the 
items listed on this page, 
complete the easy reply 
coupon, and send it to our 
FREBPGST address (no 
stamp required), enclosing 
your cheque, postal order, or 
credit card number for the 
appropriate amount. 
Alternatively, you may place 
your order on our 24 hour 
Ansaphone by phoning in 
your Access/ Barclaycard 
number with your name, 
address and details of your 
order. 

The cassettes of your 
choice will be mailed lo you 
quickly and efficiently. No 
cheques will be cashed prior 
to despatch of your order, 
and if for any reason you are 
not satisfied with your 
purchase, we will give you a 
full refund just as quickly. 

It's so simple! The best 
quality software, promptly 
and conveniently at no extra 
cost from Software Express. 
Try us and see for yourself - 
we go out of our way 
especially for you. 




PRICE £8 



OTHER TITLES AVAILABLE FROM SOFTWARE EXPRESS . . 



FOR THE VIC 20 . . . 

YH I Ihess- £7, VICAsterodds-£7.VICPank 
VIC Cosmiads 17. Another VIC in the Wall-£7. 
VIC Backgammon £7. VIC Scramble - £7. 
All programs are for the unexpended VIC 20, 
\vilh the exception of Chess ( IGK) and 
Backgammon (min. 3K expansion!. 



FOR THE ZX81 . . . 

Mazogs - £10. Dictator til. Invaders 

ZXAS (Z80 Assembler) 

XXUH (280 Debugger! 

ZXTK (2m Toolkit! £6. 

(all programs are for the ItiK ZX81 1. 



11. 



Only proems listed on thiMiHwrtiM'm^^ Byte 

see your nearest dealer 

All dealer enquiries to: Bug-Byte Software, LOO The Albany, Old Hall Street. Liverpool J-'' 9EP 



t atalotf 




THE 

SOFTWARE 

EXPRESS 

EASY-REPLY 

COUPON 

Please mail me the following 

Software Cassettes, 

(All prices include VAT and postage). 



PROGRAM 


PRICE 


INSERT 
QUANTITY 


SPECTRA!- 
JNVADRRS 


£5 




SPErTRES 


£8 




ASPECT 


£9 




THE CASTLE 


£8 




SPACE 
INVADERS 


£7.50 




{GALAXY 
WARS 


£7.50 




carry 

DEFENCE 


£7.50 




MV SH ■ 

SYNTHESIS EH 






t ALTO 
COMPOSER 


£9.50 




OTHER ITEMS 







TOTAL r> 
PRICK *L 



I enckiw chrqiw/P O tttr _ 

Or please charRe my Credh Card No 

l I | I I I I I I I I 

I I I I I I I I I I 



Access/ 
J Hardayeiircl only please. 



KRK V.\ '( )ST 1 No StJimp Required). Gores Rum iL Kirkby industrial K state Kirkby. Li verpooJ L33 70A 
Scrffwnn; Exp name of DAMS Offici Equi| ntLiverp 



24 HOUR 
ANSAPHONE FOR 
CREDIT CARD ORDERS : 

051-548 2020 

V Mail to: 

v SOFTWARE EXPRESS 
FREEPOST 

{No Stamp Required) 

Gores Road, 

Kirkby Industrial Estate, 

Kirkby, Liverpool 

L33 7UA. vc 



SHELVE YOUR COMPUTER 
STORAGE PROBLEMS . 

MICRO-STAK 




■ ■ 



lOn* of 1h* Roy MopwotxJ group n1 c empir ■«* I 

10- 12 OAK ST, HAZEL GROVE 

STOCKPORT, CHESHIRE SK7 4EJ 

061 483 8271 

Allow 21 days for delivery 



he unique and sturdy Micro-Stek has been designed by micro users to 
house all your equipment ready for use, and also serve you as s work 
desk /station for your computer activities. 

Not just a stand or a table, but an elegant piece Of furniture, available in top 
quality, durable melamine. in oak or elm finish, mea&iimg only H.87cmi x 
W.SSem N 0. 53cm when closed, 

• Handy slide out bottom shelf for easy removal of VDU/ monitor. 

• Glide out keyboard shelf- 

• Lift up writing /manual table on door. 

• Adjustable height shelf for cassette player, disc drives, etc 

Ava liable by mail-order. Send your order today, or contact us for more 
information. Personal callers welcome. 



Price: £79.50 inc. VAT + £5 carriage i- 



Flat packed for easy assembly 

MICRO-STAK 



ORDER COUPON 
Pfe&se supply one MICROSTAK in ,,.....,,*....,..,.. wood finish 
my cheque for £84.50 is enclosed /debit my Access/ Barclay Credit 
card. 



I 
I 

NAME 

I SIGNATURE . 
ADDRESS ... 

I 



NO 



If MM 







T 9t9* 



k* 










fjQutoti 



The sole SINCLAIR agent for 
the Arab World — now also 
agent for JUPITER ACE and 
APPLE! 
We are interested in 
software, publications, add- 
ons etc. 
Do not miss this opportunity — 

sand samples of all you havo to: 



P.O. Box 147. Jeddah, 
Saudi Arabia, Tel: 6604212, 
Telex 402 276 Autoram S.J. 



< 






* W# *fa wQtkt'iQ in deva'ott jn ARABIC computer 
•nvtic* rtiie*e*iM pto*» contact ui 






<* 



■¥W 



w 



5<fttfare 
©ragon 32 

Mini-games: — 4 per tape, simple but 
compelling! £5.95 

Surprise: — spells, giants, a magic ring, 

but this is no relation to the 'Lord of 

the Rings £8.45 

Amazing: — series of 5 mazes, written 
for children but interesting enough for 
everyone £5,95 

Slockmarket: — try and make a million 

in this realistic game £5.95 

For all these please ring:— 085-982-239 

anytime between 9a. m, and 9p.m. or 

write to: 

Bambv Software, Leverburgh, 
Isle of Harris. PASJ 3TX. 






178 YfXlfl COMPUTER. MARCH 1363 



A NEW SERIES FOR 
FIRST TIME 
USERS 



"Learning to Use" is a new series 
of books which introduces 
newcomers to the most widely 
used micros in the marketplace. 

The books assume absolutely 
no knowledge about computers 
and the reader is shown even the 
most fundamental operations 
such as "switching on" and 
" loading a program". The books 
lead the reader through simple 
programming and then on to 
graphics, with several programs 
which show how to achieve 
pictures and even animation! 

The user-friendly approach is 
consistent throughout the text— 
not only are program listings 
clearly shown, but in many cases, 
a photograph is included to show 
what the program looks like when 
actually loaded and run! 

All books in the series are £5,95 
{incl. postage). Gower 



To be published 
April-June 1983 



Learning to Use the Apple II1IE 

Computer {April} 

Learning to Use the Qric 1 

Computer {April} 

Learning to Use the Commodore 

64 Computer {May) 

Learning to Use the Ti 99/4a 

Computer (May) 

Learning to Use the Lynx 

Computer (June) 



READ-OUT 




v.. ■•.!■ 



OrdSfl Form to: READ-OUT BOOKS AND SOFTWARE I 

I 



SCAMP ROAD, FARNBOROUGH. HANTS, GU24 6EW. 
24 Hour Answering Service, Telephone 0252 51 0331 '2 



Name. 



Address 



Ma k« cheques psyabta 

to Newtech Publishing Lid 
Pfeese debit my Access [ 

\ .,r'ibiT 



1 enclose my cheque (or € 



Signed. 
Dale 



n 



MOW AVAILABLE 

PJease send me 

ell at £5,95 each 

irtel pcstHfffr picking 
{Allow 14dayi far delivery I 



copyies JLMfningtoUwttwPeComptitfr JUimtrqtoLteteW'tttomputef 

^LMiringtoU»thtB8Ctttfnmpu1« ; ; Leeming to tHeth* ZXB1 Cemmrter 
^Liming to U«ttaaSp*cln»m jLamin$tOltott«rjttgona 



To be published 

Please reserve for me, anrt send to me on publication my cupy ies of 

ail 31 C5. 95 each LMmmjiaUMiht^ptel.'lE Leaning to Us* th*TI»''4i 

•iiiscl- poslfit packing) b»w><j!uU5*th»l*ic1 LiawngtoLtonheLpH 



I 

I 
I 

I 






YOUR COM PUT FR, APRIL 1983 1 79 




ISO YOUR COMPUTER APRIL t983 



midland 
omputer 



BINGLEY HALL, 




Personal computers 
Home computing 
Small business systems 



28-30APRIL 

#lr©JP Saturday I0am-5pm 




Presented by 

Thfs event is the first of its kind in the Midlands, and gives you 

the opportunity to see and compare the enormous range of 

personal and home computers, small Dusiness systems, 

microcomputers, software packages, cassettes and scores of the 

very latest computer games - try them for yourself - decide how 

much, or how little it takes to build up your own personal 

computer system. 

HOW TO GET THERE 

BV RAIL Concessionary rail fares are available direct to New Street Station 
Further details are availa&Je from. British Rail Travel Centre. New Street Station. 
Birmingham 62 2C1A Tel; 02 1 643 21\ I. 

BV BUS every few minutes from New Street. Corporation Street, Cofmore Row 
and Bull Ring. 

BY CAR Bmojey Han is situated e*ose to the c*ty centre and is within easy access 
to the M I , M5 and M6. Bmgrey Hall will be road signed by the A A 
Admisiion prices - Adults £2.00 Children under f 6 and O. A P"s £ I 00 Party Booking 
For groups of over 20 people - adults £ l .50 children 75p. (pJus a free ticket per 20 sold 
for the organiser or teacher). 



Please send .adult .... .child tickets Enclosed remittance E. 

NAME 

ADOReSS ....... ..,.........,.......,....,*.,., 

TELEPHONE N0-. . . ... 



*¥»*+»* + '*■*** 



Send to Midland 
Computer Fair TicJtel 
Office, IJ!C Exhibitions, 
Surrey House, 
Throwley Way. 
Sutton, Surrey 
Tel: 01-643 S040 




I'Flii M 



YOUR COMPUTER, APfliL 1983 t81 



RETAILERS! 

PERSONAL COMPUTER SERVICES 

THE BIGGEST COMPUTER 

SOFTWARE WHOLESALER 

IN GT. BRITAIN 

WE OFFER VERY GENEROUS 
DISCOUNTS ON SOFTWARE 
INCLUDING THE FOLLOWING 

SUPPLIERS:- 



PROGRAM POWER 
BUG BYTE 

SALAMANDER 

TITAN 

# 

MIKROGEN 

MICRO DEAL 

MELBOURNE 
HOUSE 

• 

J K GREYE 
KANSAS 
ALGRAY 
HEWSON 

DKTRONICS 
RABBIT 



Save time and frustration. Get all your software 
needs from one company. 

We have salesmen covering Scotland and the 
North of England who have what you need 
onboard their vehicles. 

Until we have a sales team in other areas we can 
supply direct to you. 

Ring now on: - 0254 776677 or wirte to: — 



BRIAN GREENWOOD 

WHOLESALE DEPT. 

PERSONAL COMPUTER SERVICES 

39 RAILWAY ROAD, DARWEN, 

LANCS. BB3 2RJ 



MR MICRO 

ARTIC 

LLAMASOFT 

ROMIK 

MARCOS 

• 

DIGITAL 

FANTASIA 

• 

J K GREYE 

ENTERPRISES 

• 

IJ K 

IMAGINE 
A G F 

QUICKSILVA 

* 

CALPAL 



182 YQUA COMFMTEft, APflIU ]$S3 



ffl 1 




ASTRO 



ASTEROIDS 

A rluur v t mem o< 

Elut rLaiir gimf* r>*tur<* pnjckod 

wrththrist hvperspece, routs, 

muajple bolts, etc. Tin aoicAng' 

ptoonm it wrinwi si ptv'-c *nd 

•mpJoyi hi im ei*(ihie*4uvl 

doufakf *™o ictbcti techniques far 

maxsnun effect. 






i = r. 




INVADERS 

pjo mACjfunc es 

complete wtttau Una, Uvi ongu-jJ 

ceenuc shootout In mac hm» cud* 

sndi ihr** utnder types (!*■ 

moch*r ship! bona b m «, hi res , 

double to* pcteoa, «tc. 




ASTRO SLED 

Puotyoui high 

powered lied, d£nm th* fmjywl 
qw canyon, but be wwiiod ■ Ihe 
furlJ-*! you tr#»»l the herder n gs*i< 



<H$ 



, i«.. 



8 * 




SPACE FIGHTER 

A rpicr d<iq- r^>J 

nmul»tar whjclv t*» AHoiDtdm, 

j written mtnachiiw cod* 
*nd nee* hi tee thud* your, 
tighter U\JOUO> hohl iaopm end 

turns to «■ ritf e the eluaiT* alien 
i r .1 f? in voui *sghti 
With JO sJol) levels 




Ail il»» progiajH are available an c&taMie fat the 
unexpuided Commcdofo VIC- BO at only E4 W each (jK«t 

Ei-mt), <amd rruikw lull » a! the VIC* cetour, sound and 
joystick l»CJlit>»s. 

zxsi software 

SPACE nC BIlK , ASTRO SLOT, 

Fetw pm-s^-d wfww nf ih**» great gnw wU> 

machine code performance for U16 tfcE ZXM J 
caijrfTralliJ.M 






Una* stale EH I or VICES aiyl m*tmjn true 

when or during. 



ORJC I SOfTWAJU: 

Awi0*b!+4«w . mri'i SA£ fat Ml J«t~l. 

SOFTWARE 

FREEPOST, SWANSEA, SA3 4ZZ 

NO POSTAGE RBQUIRED 

Excellent dealer discounts available. 



We teach you the 
secret language of 



world 






Since you appreciate the impact 
computers are maWngarnomonowls 
world, vou'll appreciate the key ro>te 
Camp Deaumont can play in voui 
future. 

Because Camp Beaumont's 
computer bofTins using structured 
courses (basic advanced and rntcn 
sivc) teach you the secret language 
that'll gh/e you ahead start In 
tomorrows high-tech world. 

But without tears. Because at 
Camp Beaumont (for 9-17 year olds) 
there ate over thirty physically 
stimulating activities also 
Available to help you escape 
from computer fctitfje. f 



w& 




These include: 
nms, soccer, cridflrt. 
swimming, riding, fencing, 
inoeing, golf, shooting judo, 
archery, gymnastics, fishing, sailing, 
wtnd surfmg the creative arts etc. AH 
under the supervision of uruvershy- 
quaUfied directors. Instructors and 
monitors. And uruquery-eq«tpped 
public school or country mansion 
locations in the Lake District, Devon. 
Dorset and around London and 
Manchester Camp Beaumont also 
run day camps for younger children 
(5-15 years) offering over thirty play- , 
asyoii ■ leam activities including 
computers, robcticsvand psycho- 
bionics Write for comprehensive 
brochure to Camp Beaumont. 

Dept YC-l. Beaumont House. 
73 Upper Richmond Road, 
London SW1525Z. 
Teli 01-870 9866. 



Brings out the computer in yoa. 



EDUCATIONAL 
SOFTWARE 

EXCLUSIVE TO QREENWElD 

A rtngit of pragramirin wiinxrn by leftcnwT *nd «v<«ntiy in uh m a m«wl« Khoci 

<B'93f'*r AM C*twn«* indvdB- C0Tit(y*Teii*rji1 tfo<:um*n,»tiQf> »rKl ItK^M ROIH. 

Ex#rei**t *i* u*er-frtendly, v*ty lotiuii with a'l i'tpv» c-haekAd. ami ioclud» tnadhfaw 

codfl fnulin** 

U fit*»f Jtm »v»S*b4<! Tof 1h«8ff nvnpulcrs' 

2X8? llfiKJ, /X SFFCTnUM I16KS. 6BC * 01 TS" AHUmMny nuth™ j«(4 ^ 

«CCh intltrtiv*. S*[ ol 1} t'*S TO 

1 , was: Efl wind. Ti-r id l**J * 3 » ? diaii mrnntiw th* uww ftf* Ht*c»cr in km 

than 1 Anemptf- 

2, BAFt CHARTS ErtEar in'ormjTioP on X & y m. ind *oo a bar gtapMlinvti t>1 iftHif 

nwttt- 

3, OKO AWAGF AMS. Mougtrtm and ctobmi garr# lhat laqunrm Ifw puptt to w)n an 

HMaran to a#m j '0' <r K 

i. HANCWAK. IfScJiiKtrtH time wlffi lfj cttwhot and 10 VWdf m **ch Ciltgory 

r>r'ti*iiT *i«Si .■ 'c*tsfl<sfHM can tualy b* ar:*iecj 

6. SPELL IhVAOERS, Snool at *e cc<r«i lettor <n rtw #^jh»l»i to *p*a ih* «o«i 

ihown on the Kiwn toe a faw wc«Kft, Hjm in 'invadw' each time a mewa krtlaf a 

MltaHdl 

6. REACT;ON TEST T* C*ommt kvyboMd lamrtunty piv* p.*ttiCr 'm r*JOing dKirul 

ntmtnrt 

7, DEPT II CHARGE. P'acKe ji irw us* a' orifarvd tnp«* IX. V. S «xwcfin*l(n tn 3 D. 

Alio cov«ti ;hi poinu at th* caT(wi» 

B 7lftOl pr»tii(# in if™ u»e oftmamwd pan iX VI ccwdifiatFs -n ?D 

9. GUILlOTiNF Franeh vmvan at hangman, butynir r^itJ (tmpi inm a b*tfc« >f you 
fait to Irnd Ityt wordi 

10. OXO ADDITION & Sy&"T PACTION Noughts and curews g»nv< where th* pup* 
HHvn «h «kWiW O* »ub:r*etioti *jin to flUn j X w 'CX 

11. 0X0 MulTiPliCAIiON b DIVISION. Ai above tm: unnf ume* and divri* 

12 BEETLE ADO, Togar i(ie vltHHn pats of The beetle, simple edfition hrnS ™m b* 
■OtMd. 

Laige range of ganiea, utMcv ard educational puogiamt at out shop in Southampton, 

and Hid in Seaabury at Etectrtuntcs. Worid, Dews Rd r Sctsbury. 

A aJH * avilahta- for <Kh rnate ol conitwjuw. whnrfi conlafa* d*ta*s of wiftvv*t" ar*d 

boot* 

BLANK TAPES 

High quality CIS tepea in kbfary ease SOp. 10 a 45P each 

We stock a larot Finge ol etoclronc components, our 60 page A4 sue catalogue 
contains dtKouni vouchers and 1 cost* TSp. [Sent free lb school*. coH«g**«tcl Ditoounl 

up ■□ $b\ .ii.i hbh lo bui bwven 

TRADE E^QUtHES welcome lot efiHier solrMai* o* components 

TcRMS: C*sh wnti 0rss«f p*e*w. Host s)Oot** *cni tj>r«turrt of peat, OftfalaJ 0rd«ia from 
School* etc WB*c0fT* — minimum invoice value £10.00 



443P Millbrook Road Southampton SOI OHX 



VOUR COMPUTER. APRIL 19B3 183 



CAMBRIDGE LEARNING 

SELF-INSTRUCTION COURSES 



1 



I 



CSC 

SUPERKIT 




Utt btlrattM 



GSC 

SUPERKIT 

£19.90 



l.cirii the wonders of 
digital electronics! 

This practical kit for 
beginners comes tomjilclc 
with an instruction 

manual, components, and 

EXP300 breadboard to teach you all the basics of 

digital electronics. The course needs no soldering 

iron: the only extra you need to buy is a /, JV 

battery. 

Using the same board you can construct literally 

millions of different circuits. 

The course teaches boolean logic, getting, R-S and 

J-K fhpflops. shift registers, ripple counters, and 

half-adders. 

It is supported by our theory courses 

DIGITAL COMPUTER LOGIC 
& ELECTRONICS £6.00 

which covers; basic computer logic; logical circuit 
elements; ibe design of circuits to carry out 
logical functions; flipflops and registers; and 

DIGITAL COMPUTER 
DESIGN £8.50 

Our latest, most up to-datc course on Ihe design of 
digital computers, both from their individual Logic 
clcmmts and from integrated circuits. You arc 
first shown the way in which simple logic circuits 
operate and then, through a series of exercises, 
arrive at a design for a working machine, 

SPECIAL OFFER! All orders received before 25th 
December will be sent by 1st Class post at no 
extra charge, 

GUARANTEE Ni> ni)i 10 you. It you are not complete 1 Ly 
initiiS icd, your mancy will be refunded upon rpiurn of 
ihe item in good londmufi wiihm 26 day* of receipt, 

CAMBRIDGE LEARNING LIMITED, UNIT to RIVEftMILL SITE, 
FKEEfOST. ST IVES, CAM8S, PE1? 4BR. ENGLAND. 
TELEPHONE: 5T IVES 104801 6?4t6. VAT No 313026022 

All prices include worldwide postage (airmail a extra - 
jikdic a*k for prepayment invoice}. Giro K/< No 27891 ^9. 
f*li-j4r allow 26 days for delivery in UK. 

SUPEfclUTlSJl • E>9*W> 

.DIGITAL COMPUTER DESIGNS J # C8.50 

DIGITAL COMPUTER LOGIC AND ELECTRONICS *> £6.00 

I eficiou d * < tiff ^ u c / Pi ) jjityjtik la Cambridge L^iirninji LM 
for t ......... i"J*!*[* vhric dpplicdhlr } 

I'lf.or 1 Ii4rflr my; 

*Aec#** / AMtican Expert* / Bai-cUyt jfd / Diner* Club 

h'ir«j[d / Vii* / M*>(f rf hi»rur I Truttcarcl 

f<piry f»*tr,, Credit turd n. 




,-*t,T---------- 



1 1 rt« • ture. 



Tr(r|.tnirw trtdrr* tt<Hn wrd holder i ■ii'irpii'ij o»> VirSd t*7t*i*> 
Mrlir«> ,' uttOAT*. IliuJuJm^ Eire] *>I.lmiIiI wrj * Ljfik ilfdll 
in %i*rhr>n Jr-twn en m LwmIhIi lunk. o-t «i«<J'r Liedil t"*rd 

liuftbrf. 



H.imr. . . 



■ - - ■ I * * » # 



H(n4ii4,ikiii(i 



CSCUnit»i 



lumtii niftr Lrartunx l.irailrd, UNIT n *rv+r anil *nie, f k I. H'i *■• • , 

: l.v-. . IditiMtigilOA. < yffili)., HKO iKK» Ertglrirwl. ! Krjt n.irrriJ 
in ln<l<ilid Nu Ij2#"/b'/!, VC3 I 

184 VOUR COMPUTER APHIL 1983 



DRAGON SOFTWARE 

from J. Morrison (Micros} 



tt?l TOR, ASSEMBLER t MONITOR 

Auwntilt! rjFKtujfi* mduOs ORG. FCB. FOB. fCC. EQU. RMH «t«J t«i or Decimal 
MkMon/cublraCliQTi. Th» *£$.fWSUFn n at ttio T.vo pui &ab*l rrt» Motile* 
eetitfini krtwtgl wrm** *f«»*tinfl I** wt la i»r,w »i-d run m«hin* wd# programs 
Supplied on CKHCtt 4 vmi m*nual f5T.S5 

D.Q.T.l 

Cesium fivr lupri ipmiwi. OTHEUO. BREAKOrT. ATARI, MOONLANllE* ind 

RAFFLES 

FtMiiuntisg tnieriuiuiwn; fur lit ihc ftmiJy Onlf £5.7} 

O.G.T.* M,e<xfe 

PTERODACTYL Destroy *» the tm» tw'o'* (b*v M« Sui 0« ibt allocking 

PiEROOACfTLS, 

TORPEDO HUN Swrnior id ■■» ARCADE vcriion. JD panpictnv. SNpa iuftfwiw*v 

give hnhw poin» 

HORNETS. Vary f«« ««"<•. Kill lh« H0RNFTS n ttwy vw 9*. but b*w*r„ >Ma tney 

ihay swwop eIdwti Imng 'ttirigj*'. All ThrM g«mn onlv €6 96 

OlSASSGMSLEfl 

Tib* 4NI )CC< T» fun* *(aun<j Diiaisemtue the BASIC 10 mm how il worfcx. M«1» j»* ol 

lubrouTirvM. «ig 

Svjppted an ttnmtle 1 11.86 

DOT J 

M/Cede Q#nw. SNAKES. K* tlwn twlortt tbev k» vou . Up to 12 giant wv*» M oft* 

Ian*. 

LANDER. Una •««[ C'ik cm tn* Lurtaj surtaca 

INVADERS. 3$ tnv«dwv . trtothti sh«. 3 dVifiden. 9 UM Irnb. AH 1in«» qvw m HI 

RES 1 sound E6 9& 

CHESS M'C04*. 

8 letecubto l«v*t* Of pl*y. 

HI-ftHdulion 940OV Dl oC»ft* and pH£H. Curii-f eonuai 'rriOve' H>«tKKI. 

if»ci1ic ())ik.s» miy b« mi gf W w)b* chnu [MDbi«mi 

Suppked en Cfl***rie ♦ invirueiiaffli, ("7.95 

NO JOYSTICKS NEEDED 

Al prdfer* i^clucm. fl»lufn «f po«I MTviCA. Chequv/PO IO. 

J. MORRISON {MICROS) 
2GLENSDALE ST. LEEDS LS9 9JJ. 

CAtltftS WflCOMF PLEASE RING 10632) 460S»7 



Buy from ua with confidence 
Full money-back guarantee on all our products 

"Thank you once ■agmn for your prompt servren; yours 

must be the most user tnemitv company in this bu£inrit&l" 
G S Yorks 

"t most conB{»tul4te you not ortV on the quality of your 
goods out sho on yvur fxc^hnt service. " G. W. Soiihul) 

Quality software 
ZX 81 Spectrum BBC Vic 20 



GAMES CASSETTES 



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APPLICATIONS SOFTWARE 

Z»l (IH:.DHA?HieS 4TAHTr« PACK 

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j;jt»i.;um«ULTiOK»*-mCt CfK 

A ,w'nir<it, ^KXgs «l ore«Tavf», fvng VB u fut canwtf dl *rt £41 «r4XXt 
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16K RAM pack Mim««ii Mwopik h £28.50 




nrw/Mia 

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IM9JHBI HKHM J-V .5* fr. Ir- "V IMuMmM .J- V. 

^i i iJ» M > *n "*»* ** ** *»" »rr*B (*>»w «vmi ^«* •b^-w* ^ pfa riFw 

Dftpt. YC, 36 Fernwood, Mar pie Bridge, 
STOCKPORT, Cheshire SK6 5BE. ENGLAND 




Mtfrcn 



The first true system for the ZX Spectrum 

Sofsys is the only true software system for the ZX Spectrum. At the heart of it is 'Master 
Key' which offers User Definable Keys, and it includes our highly successful BASIC 
Compiler (Sofcom), Sofmon (our Disassembler), Sofsem (our Assembler), Sofia ts 1 and 
2 (our toolkit, and graphics packages). 



MASTER KEY 

This superb program is the heart of Sofsys, and 
may of course be used independently of it too. It 
offers up to 7 user definable keys which are 
accessed by allowing the SPACE key to act as an 
additional shift key. Up to 100 bytes of BASIC can 
be put on each key, and 5 of them come pre- 
defined so that instant access to one of our utilities 
is possible, or instant compilation of a program. 
Master Key also includes Softime, a new version of 
our popular realtime digital clock program. This 
runs independently of your program and can be 
used to time events, has a stop watch mode, alarm 
facility and which can be set for 12 or 24 hour 
modes. Master Key comes with 4 versions on a 
cassette, three 48K versions set in different memory 
locations (depending what else you have of our 
system in memory) and a 16K version. Master Key 
even offers ON ERROR and ON BREAK 
definition too! A fabulous program for only £7.99. 

SOI KIT 1 

Our 'programmers dream* toolkit, dubbed so by us 
for the immense saving it can allow when 
developing programs. It has all the features you 
could ever wish for in a toolkit: a complete 
RENUMBER (GOTO, GOSUB, RESTORE. 
LINE), DELETE lines or blocks of program, 
SEARCH for any character/number/keyword, 
REPLACE anything with anvthing else of the same 
number of bytes, UPPER/ LOWER CASE 
conversion (either way), FREE MEMORY 
displayed, PROGRAM LENGTH, VAR SABLE 
SPACE used, DISPLAY VARIABLES (which used 
and what present values),, ERASE all REM 
statements, and the first ever implementation of 
TRACE on a ZX Computer. This displays the 
present line number /statement being exectued in 
the top right-hand corner of the screen, A truely 
unbeatable toolkit at £7.99 and incredibly user 
friendly. All commands accessed by a single letter 
after a REM and Master Key save you typing in 
the REM each time! 



SOFMON 



Sofmon has around 25 features and functions 
which make it the most complete monitor/ 
disassembler on the market. It can convert HEX to 
DEC and vice versa, search for a series of bytes, 
fill and area of RAM with a given value of HEX, 
display the registers, do ASCII or HEX dumps of 
memory, execute a routine, gives the choice of 
using a printer, allows up to 9 (yes 9) breakpoints 
which you can continue from, set/reset 
individually, etc. Of course Sofmon disassembles 
too, and does this better than any other on the 
market. If a disassembly is nonsensical it will tell 
you so, it will handle every known Z80 op code. 



Finally, you can modify RAM in either HEX or 
ASCII (and switch back and forth). Uniquely, 
Sofmon actually disassembles the HEX as it is 
entered! Superb value at only £7.99 and of course 
you can enter Sofmon at a single key press with 
Master Key. Fully compatible with our Sofsem 
assembler. 

SOFSEM 

A truely amazing assembler which is totally 
machine code; enter op codes in line numbers, 
renumber them if necessary, edit lines, use pre* 
defined labels or create your own, have a second 
Stack (a unique feature) and Sofsem has a 42 
column display to allow full lines of information 
and labels. Option to insert an end-of-line 
character for printers, option to switch to a 32 
column display. Once again, unbeatable at £8.99, 
and of course can be entered at a single key-press 
with Master Key. Designed to be compatible with 
Sofmon for a complete machine-code programming 
package. 

SOFCOM 

Our BASIC Compiler for the 48K Spectrum which 
has now been brought by many thousands of 
happy Spectrum users as well as government 
establishments here and abroad and many 
Universities, Polytechnics, etc. This program 
almost instantly converts almost any Spectrum 
BASIC program into a machine code version. The 
enhancement package will be available very soon to 
offer full floating-point handling, strings /arrays 
and allow the compilation of very large programs. 
You can expect an increase of typically 10 limes in 
speed over BASIC, but up to 500 times faster is 
possible in some cases. This is still the only 
Compiler worth considering for the Spectrum and 
comes with entensive manual by Tim Langdell and 
in a book-size box. Excellent value at £14.95, 
Compile a program at a single key-press with 
Master Key! 

SOFKIT 2 

The total graphics enhancement package for the 
Spectrum. All the features you could wish for in 
such a package, such as scrolling in any direction 
by pixel or bytes, create windows to scroll 
independently, flash the screen, invert it, magnify 
letters/phrases/characters, create sound effects, 
store extra screens in memory, load screens and 
parts of screens super fast to create cartoon effects, 
and more. Undoubtably the best graphics kit on 
the market at only £7,99 (16K and 48K versions on 
tape). Includes the first ever PAINT facility for the 
Spectrum! 



SOFTEK SOFTWARE 
329 Croxted Road, London SE24 



YOUR COMPUTER. APfllL 1983 lfl& 



At Me 
we realise the pote 



MEMOPAK 16KFoidw»iiHt«t[ia$ 

cm on d» rod \o retl computing , th» pack 
trjnsfonru tbcZXSI from a iov to a powerful 
iompuEet . Data stooge , anenJ tJ pfngrmminf 
jnd AMipb Jijpliw become teiiibfc. 
For me pMicf afikitv , memory pads cm 
te added together. I* 4 i&Ktf I6-J2K.I. 
The MEMOPAK Of and the MEMOPAK 
WK L'lk; jkjc (twmoTin, jc fivonunutai prices. 




nenorati i/f 



nenopflKieK 





1 6 K: E29.90 
32K: £49.95 
64K: €79.00 

inclusive of VAT 



LHira^fflfflra 




MEMOPAK Centronics l/F 

Tew BASIC comrmnds LPRINT, LUST and 
COh' are u*d io prim m ny CESTRON ICS 
(vpe pfinm. AU ASCI! durtvieriaK groented 

and tranilaiioa uk« plK* jutomatolly wlhin 

the pjik Rc'rrsf i jpitih giu lower cave 

A JJiiionil fitiliijciajiir*- kifh resduiiori priming 

C39.90 

incVAT 



It all adds up to an efficient, 
modular computer system 



The Memotech approach to microcomputing is to take 
the well-proven and popular ZX8I as ihc heart of a modular 
system. This small computer houses the powerful Z80A 
processing unit and acts as the central processor module 
through which the Memopaks operate, 

Memotech has a reputation for professional quality, 
producing units which are designed to fit perfectly, to look 
well-balanced, and to work efficiently and reliably. 

The modular approach gives ZX81 owners the freedom to 
design the system they really need. Furthermore, the 
intercompatibility of the modules ensures that later additions 
will click straight in, to give you a system that grows with your 
ambitions and abilities. 

To ensure that your expectations are realised, care is taken 
at every stage to design features into the system to anticipate 
your needs. For example: 
1) Memories arc cumulative e.g. 16K and 32K can be added 




to the Memopak 16K or even to the Sinclair 16K RAM pac 
2) The HRG firmware allows commonly used constructions 
(such as scrolling,, shading and labelling graphs), to be callei 
by a few simple commands. 3) The Centronics IT converts 
ZX81 character codes into ASCII and extends the print line 
the width of the printer, still using the LUST, LPRINT an 
COPY commands. 

As one example, a system with 16K of memory and 
Memocalc is all that is required to perform the same 
sophisticated numerical projections as a computer at 10 tLtri 
the price. The problem may be as complicated as a cash flow 
or production schedule, or as simple as household accounts 
pocket money budgeting. If your hank manager wants to se 
cash flow, then a single print instruction to the Centronics 
will give a printout which is more than acceptable. 

The example system which is shown, on the other han< 
would satisfy the needs of someone who wanted to enter dat 



How it all fits together 



You can see from the diagrams how various 
Mtrnotech.' Sinclair units can be 'combined. 




T66 YOUfl COMPUTER, APRIL 1983 



otech 



fjjal of your ZX81 




M EMOOALC The xitea display behaves 
as a 'window' Oil 1 ht^t sheet of paper on 
which a libit ol numbers is laid out , The 
(imimum sue of the lable is determined by ih* 
memory capacity, ind siih a MEMOPAK 6*K 
a table of up tt ?00t) numbm with up to tt(J 
:■ .■•*• ,.: W^lumnt can be specified. Each 
locaiion in. ffcc lable can be either a number 
whJch is keyed in Of a lormuh which generates 
a nuir.bcr 
£29.90 inc VAT 



MEMOPAKHRGih. SkfetJa 

down the consitatn^ imposed by opentins a: 
the 7.\% \ chara let lew! ind altuw* high 
definitHo displays !o he generated. All >4S v - 19* 
individual pueb en be cootrolkd using simple 
commands, and (he bulk to tofiwat enable* 
the user io work interactively at lhc dot, line. 
character, Nod and page levek. Strolling r 
flashing and animation a re all h ere. 
E39.90 inc VAT 



ncnocau 



L 



3 



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u 








MEMOTECH KEYBOARD 

Tin Mc]tn>;c L h plug-in Keyboard plus buffer 
pack :akes rJie effort cut of data entrv for ZX8 1 
users. The Keyboard has a light professional 
Couch ind is housed in an ekgam aluminium 
cue, The simple plug-in sysiem means ihai yen 
it mil ohbg.ee in open up your 7.XK1, use a 
soldering iron or invalidate your ZXSI 
warrant)'. 
C49.95 inc VAT 



via a light-touch keyboard, construct and label graphs, and 
then copy the screen to an 80-column printer. Only 16K of 
memory is shown here but with additional memory, more than 
one video page can be stared. Up to 7 pages can be displayed 
in rapid succession to give animated displays. 

Looking forward, Memotech will continue to back the 
ZX8 1 through 1983 with fast storage devices > pressure sensitive 
electronic drawing boards and more software packs including a 
Word processor* an R.S232 Interface and a Z80 Assembler, 



MEMOTECH products are available from major 
branches of W.H. SMITH'S & JOHN MENZIES 



Memotech Limited. Witney. Oxon, OX8 6BX 
Tel: Wilney 2977. Telex 03372 MemiecG 
Pleas* send me ,he following Memotech products 




I I 



KEYBOARD BUFFERPAi; 
The Buffer Pak perfortcw a "twusekeepiflg" 
(unction f« the keyboard, aieitking directly 
with the pan at lhc baft of you ZXSI . 



i^^^^^^^^m 



I enclose a cheqi/e/P.O- lor ,^^_^__ 

or please debil my Acoess/Bardaycard account number 



Name and Address . 




YOUR COMPUTER. APH1L 19S3 \$7 



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Just getting started in computing? Or perhaps you're 
already pretty knowledgeable and would like to extend 
your programming skills. Either way Your Computer 
pack issues can help to fill your need for reliable and, 
above all, relevant information about home computing. 

Every issue contains reviews of new computers, 
software evafuations, and surveys of add-on equipment 
together with informative articles which telJ you how to 
get to grips with graphics, sound and machine code 
programming, 




•*•* 



To obtain any of these back issues please complete and return the 

coupon printed below. Prices per copy including posr and packing are: 

United Kingdom: £1.50. Europe: £2,00, Rest of world: F2.50 (by Air Marl) 



issue (month) 


Year 


Quantity required 



















































Facilities provided on the Sinclair 2X81 and 
Spectrum, Vic 20, Acorn Atom and BBC micro have 
been examined in article after article, providing a 
comprehensive introduction to all the most popular 
home computers. Just run your eye down the Contents 
of our back issues and you'll see what we mean. 

To order back issues complete the coupon at the foot 
of this page and send it with your remittance to the 
address shown on the coupon, 

January 1982 

Reviews" BBC micro: WOrdprOCeSSing on Atom. MotDhy v. 
Champion (chess computers} Game — Trdvure ptpusO 
Education — ifxei programs lor school use Vic-2Q Software 

ZX&l Graph* s A-0 conversion Interview — Kenneth Baker 

May 1982 

Survey: ZX Software. How to write a chess program. Games ■- Vrc 
20 Tank Battle; Magic Squares. How to show off your 2X81 . 
Joysticks for the ZX&i BBC Graphics, How to write a word 
processing package. Interview Richard Turner 

June 1982 

Reviews Smdair Spectrum; V«C 20 Software, ZX 81 Keyboards 
Games Vic 20 Mars; Qitielioon Fleiridise Atom Utilities ZXSl 
machine code monitor How to build a portable computer 
Interview — Ron Bissell, 

July 1982 

Survey Atom Sol [ware Spectrum Graphics. ZX 81 Colour Board. 
Games — Dog Race. Gemo Guessing Game. Simon Challenge 
BBC Sound. ZX a i Ois -assembler programs lor r*x 80 interview 

— Richard Altwasser. 

August 1982 

Review; Dragon 32. Survey: Vk memory expansion. Spectrum 

Sound Games — Demon's Domain; Vic Duck Shoot £K&1 

machine code (Part 1). Atom I lie handling. Ecological modelling. 
BBC techniques Interview — Tony Baden. 

September 1982 

Review. NewBram Spectrum Software Sound on ZX 81 Games 

- Vic Dambuster; B-S2 Bomb Run. V:c 20 Assembler Spectrum 
Disassembler ZX'BI lnde*ei ZX-81 machine code (Part 21 
Midwtcti MC control Computer. Interview — Hermann Ha user. 

October 1982 

Reviews; Sanyo PMC range, MPF-II; Commodore 64; Colour 
Genie Survey: BBC Software. Atom Forth. Pascal tor Bask users. 
ZX word processing. Games — ZX 81 Pinba-ll; Vk Catacombs 
Atom text BBC control Key. Spectrum Assembler. ZX 81 machine 
code (Part 3), Interview — Douglas Adams. 

November 1962 

Reviews: Jupiter Ace, Low cost Piiniers. Survey: ZX81 Software. 
Atom. B8C & SpecTium Sound. 3D Graphics tor Oraoon, BBC & 
Specirum. Vh; (vtlghi ftacw , Dragon Artist, loierview - Clcve 
Sinclaii . 

December 1982 

Reviews: Sord M& & MPFl, Vic Soltwere. Games Special: 
Spectium Flight Simulator. Atan Chicken, Sharp Coup d'F.Mt, 
ZX81 Probe, Vic Break (ml BBC M*7a Muncht* Atom Quest 
Survey: Vic Software, ZX81 Chess. BBC Music, ZXB1 Forth. 
Atom Accounts. 



To: General Sales Qepx. , Room 106, Business Press International 
Quadrant House, The Quadrant. Sutton, Surrey SM2 SAS 



Please send me the back issues detailed left - for which I 

enclose cheque-'PO for £ payable to 

IPC Business Press. 

Name 
Address 



YOUR COMPUTER. APRIL 1983 189 



SPECTRUM AND ZX81 HARDWARE 




PANDA 

The lamous Panda Expandable 
Ram Pack. Massive 16K addon 
memory which can easily be 
expanded to 32K with an 
optional plug -in. module 
Supplied in rugged no -wobble 
design, rugged, injection 
moulded case, contoured to fit 
theZXSI snuggly Compatible 
with other addons (printer etc). 
LED on/off indicator No additional 
power needed jllsi plug in an go, 
British designed a^d made from top 
ity components— |mjT v £OA CA 
throughout, guaranteed 12 months UINJjjl i»Z4"OU 

EXPANSION MODULE 

The 16K Panda' is easily expanded 
from 16K to 32K by adding this 
expansion module as and when 
you need it 

ONLY £2000 

GIANT PANDA 

Giant Panda the two together . Buy the Panda and the 
Expansion Module at the same time for a gigantic 3£K bytes 

Complete at a special pm ONLY £40*00 

PROFESSIONAL CASED 
KEYBOARD TYPE FD42 





FOR ZX81 OR SPECTRUM 

This fan soils, best selling product immediately converts your EX 
Gamputei into asturdy, extractive and professional unit, with full 
size typewriter keyboard A tough plastic case encloses the 
keyboard, PCBand power supply. It has 42 keys including all the 
ZX8 1 /Spectrum graphic characters printed on them, The full 
travel key switches have gold plated contacts and guaranteed 
life of 10" operations. It's so easy to install! You simply unscrew 
the ZX PCB from its case, screw it to the FD case, and plug 
in the keyboard No soldering or /YKTT V £OQ fin 
Lechnica! knowledge required. (JlMJjI dt£?°UU 

TYPE FDS FOR ZX81 OR SPECTRUM 

Our new advanced keyboard has the same, fine specifications 
as the FP42 system, but with a new re- designed case, 
space bar and double-sized shift and enter keys. A must 
for the discerning ZX8 J or svitrr v oin ac? 

Spectrum user VJWLl Sa9'?0 




ZX KLIK — 
KEYBOARD 

If, like many ZX81 

users, you are 

fed up with 

the dead feel 

of the touch sensitive 

keypad then consider the well 

tried Khk Keyboard This is a 

simply fitted genuine push button keyboard which has been 

designed as an exact replacement for, and is no larger than, 

the existing keypad ■ Fits on to the 2X81 ■ Full 40 keys 

plus one spaie for any purpose ■ No soldering - just plug in 

■ No trailing wires ■ Clear permanent two colour legends 

■ Positive feel and sound as data is entered. ■ Speeds up 
programming enormously and reduces errors ■ Fitting 
service offered £2 00 extra 

(remember to send your ZX8I). 

THE SOUND EXPANDER 

A superb economical addiiion to your ZX Spectrum. Clear, 
dynamic sound effects will really enhance your enjoyment of 
the new exciting programs available for the Spectrum, Our 
new sound amplifier comes complete with leads, volume 
control and built-in loudspeaker. Simply plug into the mic 
input, it fits neatly on to the back of AlTT v **. » n n 
the Spectrum, ONLY £7'50 

STOP PRESS 

1 6K Spectrum owners - upgrade to 48K with a Spectrum 
Upgrade Pack complete with full 
instructions. No soldering 

COMING SOON! 

Our range of products is constantly under development and 
review. We have selected products from leading 
manufacturers in ihe UK and believe these represent the best 
value and quality combination on the market today, 

PRODUCTS ARE STOCKED AND USUALLY 
DESPATCHED WITHIN 10 DAYS. 

I 1 

. I wish lo order the folio wi no ■ 



ONLY £3500 



Quantify Item 



Amouni 



Panda C» £24 50 mc 



Expansion Module (<> £20 00 mc 



Giant Panda {<* £.40-00 inc. 



FD 42 Key braid ZX Sped turn' fr £23-00 mc 

FDS Keyboard ZX' Spectrum ' (a £35-55 inc 



ZX Khk-Keyboard & £2650 mc 



Sound Expander <<* £7 50 inc. 



Spectrum Upgrade Pack («i £35 00 inc. 



TOTAL 



• rices include VATandpost and packaging All items i include a 
full year guarantee Cheques-'Posiai Orders etc should be made 
payable to AFDEC Electronics Ltd, 

Nam*' , 



Address . 



Overseas customers add K post and packing 



Yd 



AFDEC 

ELECTRONICS LTD 



318 Kempshott Lane Basingstoke Hants RG22 5LT 



1 90 YOUR COMPllim APRIL 1 983 





CLASSIFIED 



661 3036 



.Britain's Biggest Selling Home Computer Magazine, 



ATTIHTFOW P*A<t(JN AND 
WtCTHJW OWN1BS 

IWAHI 

oBAcioN s « otvtti n 

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d-nVuhv f ■*"! 4 v^flfi* Ml upioi full hVvs 
Mk. Contimietrt **fti*y el ■*••, b*i< 

fRUIT* 
HWOOK H *"n 

SPICTRUM *•* iB-bomcc 

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drum* S»m Sushi IsW G«"nb>4 
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Jampot rUSWdnmi m»n:j(i( tur«d f« ««*. 

KnCT0*lTH 

DHJIC10H U r IB DO tJO t» 

•HCTHLMUItK ilUItU 

A rri*!iv> 0*™ ««h miK/iint cods (a 
•Mrs lip FWI lht aliens tram »•* mr i« 
UWWjNna i™' 4<l*n4M MM, luiKiti 
lim, p)wr and Mrt-T.it »i ml b-.h 
Spatial DttM - 
DRAGON 12 a1tr>n-slor fU0Ci»« 

spectrum <ibk bsttiiDrnawnsM 

Al py« *iefcn»v». m»i on(*r only. cfnH3i.-m 
of poaurl ordsri W 

WtfAAb Sa-fTwiRE. P.O BojH, 
nuif-tHUUNt. Filt, Kyll Ww 
Send S * I . IW tul cooum uukjjot 

Fl * | * U*H IDdi' H WnMTl***" (W»J '«f 

i^nrfor qujkry DAAGOM or 5PECTRUW 
*ntwnri 



BBC Micro A/ 8 Uteri Opa-ril* youi urni 
Tits ten compatible inform* lion service of up 
10 9,'Z5 On-lin* PHJ«» wilfi rcjl |ime (laie »nd 

ck>E*. ideal lor shop*, etfiew. public 
iri»ti!u|if>«i. educational miablishJivonti etc 
The Viewteiit package comprises two inler 
active, programs lor page Cm l>on and display, 
comprehensive UHI guide Snd rremonirra tit?n 
papes Choqur,*.' POi for fS.flFj at KAF for 
detail* to If Se*V*». 27 Waterlerd Park. 
RadtlOck, Avon, HAS 3TS. 

45,'3 
Spectrum Tap* Heads • Roads* (l6.'4flM 
rsada th« information hidden in Ihe header, eg 
code block addresses, lengths, start Un«. oK 
Cassette £7 96 ■ SSSp pep W_ Bum*, 36 
luecomba Road. Upfsei Shirley. EoulK- 
iinipron 03-3 



ZX81 16K 



FANTASTIC VOVAQf: H««l lima *imii 
lalion bv a («tuf»r in ArMttomy. Sf>»rth 
ths blood v«»al» & tirrtlfny tha chU - 
1han bo! oul «+in - wWyll f S 5ft 
RTAflTHEK: Gwsd praientslion - 
Gflf*Liit Map, L-R S^an, 5 A Scan. F '<' 
Ph»*»r». Firm Photon tofpaotoa*. Boom 

Shiekti A rnalry flood vt*<o1\ ■ CS 95 



UK101 t8K, 16x48} 



FANTASTIC VOVAGE LUNAR 
lANOEA. 3D «AZE. X WING FIGHTER, 
STABTRCK. C5W f«h 
PI04H) llata moriilAi [now WEMONI. 



From: K A SPENCER, 

74 D overs Park, 

Bajhford, Mr. Bath, Avon 



Chess Partnar 20W Ci»»a CompyH* wnih 
S«n»orv "board 8 LnvnLi oT jiljy UmpfJ tw.cr 
only £Sd no afftrt Gou. 93 Stephana f-vt, 
Moct|m*f. Ro+ding RfiT JKA 

32/3 

Acorn Arom 1?K with Joystick flrnj C80 

Soliwa« anrj boot*. 8«8*iri «i f t05. tuxon 



MONSTER SOFTWARE CLUB 

SollWlf* llhiB'V lor tha 

DRAGON U 

Tap qujl-ty cflal*Ctai 

FORHIFtt 

All tapes usact wiltt th« 

MjnuliCtijrer'F pcrmtjjscm 

SAE re-f iSoteJi 

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B lanrw): Pnvc. Uvh< FVk 

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56 ■'? 



0F1IC-1 OWNERS Tangciino ciealed Ortc-1 
now TUG croaf** tha nit An ■ndvpandanl 

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orooratinr* i>il*m iup>port Monthly 
Nawatonsra. Sottwarc. Hardware, Rmwn, 
AdVte*, ind t«t* bimi. we huv« ■ p*ewtn 

racofd of parlo<manca on ouf iyt(«m Jcun 
TUG, Vw'll like u», we del Send ft 00 • 
S . A ,E . <A4T f« tarnpaf rtavrtiarar and dou.hi 
TtHefina U**ri Group. 1 Mafttwrougti Drive. 
Wode, A^or., BS22 5&Q. 

aa/a 

Vic 30 ownen Elciung educaiiijrial prrjflmm* 
Suiutote lor Child ran Atfad 6-1? yuan fS.OO 
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eW 



1 



PROM SERVICES 



Permanent isttwaro for ZX mierot 
IXS1 

3K EPRQM board 4 EPftOM T of 2 £30 

EPfiOM 1 -t0 toolkit iourln?[ [10 

EPflOMJrapidSAVErLOAD £10 

•FPftOMiyOiSUdnerrlfCinooHfJI flO 

!.PHOMe>/anilAd»Eriib*n flO 

tx&anjjon Board - 3 »Foi C1& 
Gie&h*! Board -irvc. ^K EPROM f 24 50 
SPECTHUM 

EPfiOM BOARD £19 

1 6K RAM PACK adaptoi f 6 .50 

32lin»|.'Cltlnnrrl(flJlo1it»2>C8l| £16 

frigs tor-.rnM. lo< 23 at 2a way £2 .60 

Edge cord 33 or 38 way/ 75o 

*Tap*V*r»lnn - *p#CL.I ptlc* ftj 

Many otfier W produtt*. SA£ tor !t»|. 

tPHOM SERVICES 

3 Wodgavyood Drive, Laedi LS3 lEf 

10632} 687183 Ifya 



£ps£Trum 4SK special intraductDry ntfar 
tree diary ivatam with the Bank Account 
System written Irj prolsiMpnal ^>£nd.ardv Tul 
stiaen srtiry, mainiaifii iran&scuart 1ile ot 
S landing Order*, Salary. Cheque*, ate., printi 
SiHrncnft. why W*if for th^ B»nk, c**«^tir 
. ir- 1 1 i. V!- manual, fS 00, Kim Gauldiiane, 4! 
Burleigh Avenue, WalNnflton, Surrav. SMf 

7jg. lan 

Specrrum Programmint) Learn Banc Pro 
grarrwning the ***Y Wrtlf wW clw l"Hv 
structured ceuerte couraa. tol tha compuler 

teach you 1 7WK oF bcdgramt endlrva with a 
cqmpuisp,»ed mann. Only £3 95. RarclaycarCJ 
atrjretad. Suifsx Software, Wilwnri HOua*. 
P«i,*ft-i*y Bav, SueseN. 



ORIC-1 

ZX81 

SPECTRUM 

MANAGEMENT GAMES 

DALLAS. A gams of oil enplottat'On m 
TtMH. CHtoceni art ^aauired on pur 
ehaung canceutoni. the movement end 

UH Of (friltino nfl*. and th» &ulkjirl(i Of 
platform* and pip*lin*», Can you take- 
aver the Euing Empire 

AIRLINE v ot i mu»r decide on number ol 
aircraft to operate;, loan and fuel con- 
tratu. wttgitwr w uMV of eh*r»r. a^d 
taveli o1 »t»rf«ng and mainwnance. 



rmcf 

ORIC-1 oSK 
7XB1 l«K 

SPECTRUM 16K 
SPECTRUM 4«K 



ffl 
£6 
CB 
£B 



Two 

Ct4.50 

■:s ',■": 

fS&O 

£10.60 



| 1 |1 |J 



£5£PT. YC 

14 Langlsri Way 

tondap SE3 FTL 

60/3 



IMMEDIATE DELIVERY 



SPECTRUM 



MICRO 10 

BECOME AN EXPERT IN 

COMPUTER KNOWLEDGE 

9 PROGRAMS (OVER 100K) 

1,000 MULTI CHOICE 

QUESTION/ ANSWERS. 

LEARN HARE POKES 

IMPROVE YOUR 

PROGRAMMING. 

M- CODE h BASIC 16/48K 

Hi-ras. Cotowr Sound etc 

Sand Cheque /P.O. to: 

M.K. CIRCUITS 

36 ST IVES CRESCSNT 

GRIMSBY DN34 5SJ 



."j J 



MZSOKA Horierate Anliyaii, Winntrt 

Salore, A *erieu* ptotfttf. C li n ne; fS.TS 
igTaill: Paragon Mopralde Woodiandf 
Wjmbof nf> Ooihi 

Warvlsd Uro+nfly' Arc4d»,1yp» ysmai 

program* far micros Speetium. VIC 20. 
Dragon. Ork We pay tap royiiltis* or cash 

nulriflht for ooOCt eiCtlHi^ oiiiift*. Maugitdl 
tnark#|irri) aruurap manimum reward for ycnir 
Aom. Phone David on OS) B339143 nr wrlle 

fvt-itiTWish, Ground Floor, Raih Buikfenrj. 
Stanley Street, Manehnter MJSPri sn4 hij.ry 

lf3 



LYNX 

Soflware available NOW 

MOONRESCUf- tovn tFin aairoiiaui out 
njitctl your fuel you mutt net bickl 
OMLV £E inc. 

60 Out wood Road, 

Herald Green, 
Stockport SK8 3LZ 

sava 



Frcm Old Kar-t Road la Mayiair. The famous 
board gam« 'or the BBC Micro (32KI short and 
*Untt»rr| glmt OptiOf*. G*ms*jiv*i tiCiliry. Up 
to tin playonr including tJhe computet who will 
cont<de< deaf* and otter e"«h#nge*, £4, ■ AS 
Saltwitrs. Dept YC. 3lA Hilll-rld Dr.vp. 
Hetwill. Wtar**uftd«. 

Atvn Adventure invr»tiD«ie »tr*rtg* haepcit- 
inoj in the 0*d Wtnoi - (ti»n try ro meape 
tZK Mi'C t'6 00 front Fourth Dimension Soft- 
wars, to KtHearn Drrv*. Paiilfy PA1 3DG 

43/3 

BBC quality p^oarams. Low once*. "Chun* 
Clock" [16KJ - £1,95 "Tvyrj. player 
aieekiaek- r32Kt - C2,45- Datum, 22 
Che*tefli»kf Road. Southport. Merseysida. 

Ut2 
SHMra PC 1211 with CE 122 prrnter-caHelte 
al*0 Sanyo MIQOl wnTh foil c4«44tte plogram 

library, apiara paper, bsnerle* ate. A complete 
pocket compute* lyiiom Th* lot f100 P*rt 
purchase comdered. Tel: 0£t >*f> Ja£* 

?V3 



VtC 20 b«t ind Inwt So'twara tupnrr rtMr 
club wrih unbeatable offers. Hire a caiealte or 
cartridge then II you decide to purchase n 
simply send u* the hulanit" »nd w# Witl r*+uftd 
your h--ip crwg*> or return the cauelto and if 
dseved hueanothst. Nota no chlkjation to buy 
whoi»o#vot Save pound*., je»n ComcluD 
todiyl Plot • Super Bonutl AH tubec-nbrr* 
may purchase a usnuin* Commodoru IfiK 
Rampack for £49.96 or an 8K fur £29.96 Atso 
rf you dedne Ihij otter, then accept a (resj 
Corn*ott Dr* ui ,hrt HJNftXI c*»M«e Rflr* f6« 
roniwift Worciwsaii.il, IB-18K1 ijmTIt RRP 
PR. Send for nwmbershirj form and free 
catalogue to CurmrFub. 34 AH&n Road, Ayle- 
Hone, Leicesler, 

4i i 



DRAGON GAMES 

Throe Fast rrsoyirvg ARCADE Style ojnin* 
'.vpiIHtii in nvmhifw Coda lev you- 6ft AGON 

SNAKES The only way to kilt them n 
stool them 4-1 ihe heed Your man may 
move aAyyytwe in ih* fotMT. Sntke* 
enter o>r* at a lima, il you don'i kill ii 
quickly another w>U enlor. Up to 17 
maeem ef one timo Irf you bve that krngi 
Ftniaelic sound and orapbits 
LAND £R L and your spto* craft on on* of 
the landing oadi [score deoertda on 
chosen peril. Hkjh rrgsoKilioh picture of 
cr*h and lunar surface. Vary mipnetjive 

li-.; .,; 

INVADERS fha> old favour ilr Fsa,tur» 

include 36 Invaders, mother ship and 
three flefftfidaie. Si* dejrt Hi tf:iiin . 
scota touTiuwi. Nine saisttaola skill 
leveta,. AM in High rfsoknitm COLOUR 
graphics and sound 

All Thfl£E GAM6S ON ONE TAPE 
loidat IK~.T2l only t : 6 36 kid, I* C mi- 
J. MORRISOMIMlCftOSt, 2GE*n*d«le 
St.. Leeds LS3 9J J. (06321 480 96; 

10 I 



TEACHER? S-pstlrum o*r»r' Die your 
machine. Mark book on csscsite. Class tart. 
Yeir Its! Sort alsVvtwtiicaBy Input niertj 

Corivetri 10 pc-menii, grades, ranks. Graph 
results "2" scores lor rjaar compar'Son 
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and rsatos. Farm, B T ho m p son Road, Boiion 
Tat: 10304146007 ,3,1 



WORTHWHILE PROGRAMS 

IflX 3XJI and *8X Spectrum 

RRBT AID teaches She prrncipkM of 
drst aid Ful«v sconrvj. Age* 13 • 

COMMUNICATOR Mono code. 

.iphora, verbal rooortinfl, use of 

telephone. Ideal for cubs and scoui*. 
f4 99 each State machirur ChoQpee'POs 
IO: 

Network Cnm purer Systems Ltd. 
39 Bampton Road, Luton, Bed*. 

a/t 



POOLS PREDICTION DATABASE We can 

supply Enotnh Footbai League results 1977-82 
m computer fprrntl, with Itarter aruHysia 
profliams - 0r^c.■' Taper* f t$. t? year tape* 
£7,60!, Sinclaus BflC, Pet. VIC, TRS, IBM. 
etc, SELEC Solfwere, 37 CouncHot Lane, 
Chaidle, Cheshire. 06 1 42ft ia2\* 
I Access ■'Barclay wekomol. 

16 3 



BBC 



EDUCATIONAL 
PROGRAMS 

Help your child to go streets ahead in maths 

Send for details of our quality programs. 
COTTAGE SOFTWARE, HEATHER COTTAGE, 
SELLY HILL, WHITBY, NORTH YORKSHIRE Z3 ., 



IT! iUR I OMPijii h .M'Hii 1983 IS 1 



BBC (32K) SPECTRUM (4HKI 



NEW RELEASES 

INVISIBLE MAN - nml« Spectrum! 
Alto for BBC and VIC20 £5 W 
STORY A - BBC only - (UTl eke * story 
book , but you choc** the pfoi. Aga* 7-1 1 

PONC MAN - BBCojriy - hegehbtn 

Ihs luH slops You pill IhfJti back - f/ *i 

REAL EDUCATIONAL PROGRAMS 

Sftt for details 
I ^tfc Lowmoor Cottage l|YC4]. 
VV- Tonedals, Wellington 

-U ^ Somerset TA21 UAL 

t 0CM7 7m n 3, 



ZXfli »r>d Spectrum educational *rni games 

so'rw.irn Mind $AF. n Hcs1*d ?J3 l«nirvr*« 
Crescent VluMKafOugh 

Z7'2 
Ma mora eyestrain with you* ;x&l Video 
inverter displays sharp white ehaiitclers un 
solid black bacAgfound TV screen. A togfllo 1 
switch loll you choose between norma' end 
reverso. The *m*H PCB fill on top o' Hid kjg»c 
Chid rreud* your ZJCB1 KH F4, Built ft. 
mc'udas easy I a follow instructions 
VAF/PtjP. Sendf eh«|g«/P<0 10: 0. Fritted, 6 
Stanton Rojd Thehvall Wamngipn 
Cheshire. WA4 2HS. Box Net 1 

9/2 



SPECTRUM EPROM CARD 
(£19.50) 

Plugs *mo it Moitarboard lZ»tolf 16 961 
Uses unused ROM wn (14832 156151 
and 2S16 2715 t2Kt end 2532 l«l 
EPBoMS. Tape Control)* ophonel •*». 
I +£3.49. 
Many possible me* mdudtrvn Spec*' 

ch*i. s»t*. m,c & basic, ens OK j 

RAM ^ADAPTOR IC9.KI plugs aito 
ROM CARD EPROM 31 I2K.I iC9.35i 
programmed wiltv RENUMSER (me 
GOTO. G05JB. RESTORE, elp.t. 
SPRITE Chars, pruned from any start 
position, any magrnficalM>T. iGH#ted b 
faf (acted. WORD PPOCESSOfl for 
prepn of TEXT vwth justification. DOG 
Char. Sets I minv o(nCrt 
A-Mi*-iilifc!*ixai EPROM BEAD CAflO 
IM.7SI. EPROM t [with BffEAiCOUT, 
LIFE *TKJ TOOLKIT <Cd.25>. 271&EF"FlOMt 
PFOGHAMMER IC29 .751. 25U P,S. Ifof 
Programmed Ito&H P6P CI (U.K 
only I. C2 IwnEtHl. 
SAE pleese for fir n J emit 
ORME ELECTRONICS 
2 Borrippor Ad., CAMBORNE. 
Criir.tf.sll 

&F3 



BBC JJK. Accuta:* tmilition ol WW2 
Submarine attack on Tirpit*', written by ei 
submariner. £6 for up*, charts, etc Sett 
Options, 6 Rerwigiui Grove. Lineotn 

1. -J 
VlC-JO Software Cassette*. F39S each >nc 
postage No. 1: The PJAdM. Spacewarp. 
Biosfcoul No. 2 Skia-, Cowboy ihwrotH 
No. 3: Scrnnblo. AS foe mo Ltncjipandcd 
VlC-20, KM* Hi.R*4 »IObr flrophKi and 
sound. Cheque* ' P O* wA Chm. fw»4m«!. 
Ew*n, CiftncvHof , Gtoi . GL7 6BU 

38/2 



PRAGON 32 or 
TANDY TRS SO Colour 

Lots of programs — lots of useful 
hint* tfnj inlijrrTVJlioo EVERY single 
month in "RAINBOW" an cycling 
n*yy 200 P3Q0 mag«ine from 
U.S.A. 

Send fl.Sfo lplu= liirgt- b6p *.3.C.I 

for sample isSif* 10 

ILKAN ELECTRONICS IDcpt. YCt. 

FH£EPOST, IT Bury Nl->v ftoad, 

P'estWKh, Manchf-ilHr Mto $1 / (jr 

i«l«fKXie 061 738 7613 (24 hour 

service). 

4/2 



16 43k Speolnjm: Compuhiye. eneitlnq. 
q<.*bi>' s*m*« Siampki - Tap* one) Bomber 
- Luivt»<Kte* . T!ftefitifOf>e t Eootateti 
(3,50 •- n*t Ssfksui Prowanw - Word 

£40£6**f* *!c - from f3 W SAF lor 
brochure. Ftaysolt. 24 Court Avenue, Vanon 
Bfj1$4EP. 

90/3 
Oragon Tonoin BoMAnfi limp'ov«d graphic*) 
(»p* fV CM Nmmin, 12 Maiden Pari. New 
M»ld«i. Suriey. $Af fw fu* bit. 

VIC 20 I Standard) game* mctuOti Metoon 
murKhy Mochtruiler Cruektn Dambu*i«r 

Irttlhrnir* pkji pthqrj f 4 SO |h« loi on 
cvwetl* A. OutliJi. S3 MamKild Hoad. 
ScunthcKpe. South Humbertide 

31. '3 



2C IK 1X81 GjiYtt*: DuCtifK»t r Conmeei 4, 
Bartieihici. *k * O't B X'», Solii.ir, 
Biack^ack. Slocks 'n' Shfrea + n»*a, 
Cassette & mitrucironi onry r39g.l 5 16K 
Frogger. Bacfccj*mm9fi d Motorway, Frun 
M^hine. Harto.rw £3.9S, or sU 2S for £6 96 
5- K*»V. ' Ath«r|»n. Hovm. Her^vvtKrf Ro*J, 
South Croydon, CR? 7Al 

4SV3 
MZBOK. [>ragon Crown 48K Epk Graphic 
Acfvecifjio. wvlh m/c - S(iu*in. m/r 
Fjvounte Bolh lor lb 00. Squ^rel Sod, 33 
WJicm Rwl, Edinburgh. 

3* 3 



JUPITER ACE 

USERS CLUB 

faewsicitsjr, software [both 
games and uiiJiiiesi. adapter 
for 2X81 add-orwn 

SAE for details. 

Remsoft. 18 George Street, 
Brighton BN2 1RH 3?. 3 



SDeetrumvZXS.1 Gimn «.»/n .50, Vehtin. 
Mao/Htt, Hangman. SpHuIre, Odd One Qui 
Pfcj* Another. H. Kkrcwon, 39 Vaie* Sir*tt. 

LrverpoCJ. 39/? 

Sfiarp M280K.'A S-Oftwjira rtadv for 
tfitfttodujti- hir* lrr>m 50p. S»nd SAE few 
maiYioerihip deiaid sod free caialogrut, K SoH 
Soltwire CEHleclwn, 58 Bolhem Lane, 
Betford. NoRmQhariifhii*. 

7/3 



COMMODORE W Vic 2C 
- Atari 400. 800 - CGL Home 
Computer - the best chess 
computers — all obtainable at 
the lowest pficfls by mail order 
from: 

D0SKA CHESS SUPPLIES 

IftefjtMered Commodore Deal e r] 

PouKon-le-Fylde, nt\ 
Blackpool Lanes 
Phone: 0253^889742 

14/1 



Colour Genie Pooh Program * Free Blank 
Daw 1*0* £8,00 Spectrum Poole i • Teoa] 
(4 95 ZX8I vrtttm Ino tofwh C4.0O M.W. 
Ho*n«r», 80 Ompa-rKiv. n Street, BeNOiU, E 
SwmTN33baE. 40 3 



BAUG SOFTWARE 
Introductory offer ATARI 
7%% ofl hardware up lo 20% 
off Software. Commodore and 
Dragon. 10% off ZX81 kev 
board L26.00. 

Telephone 0232-621221 for 
details P.O. Box 123, Belfast 
BT10 0DB. 



Sjie El, 000 on youi 
Your Spectrum 18K wH not only tinow vou 
how you migh!, hut ettti o>to you a WHk* 
recuyment calctilaior . I| «ven wrwt » yo»r 
bar* manaoar 10 taka AuSranlao* of (hit no 
e>Ui coat nw-thoo Send CS ;o Compvta- 
Schome. 55 Buckingham Bead, Swctdon, 
W*» 17 'i 



JUPITER ACE SOFTWARE 
from FORTH DIMENSION 

ACE INVADERS 

Stop the fait moving and weaving m ini 

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Qtxl-zr lhn rock* «mj the debnt, three 

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SPAC6 PATHOL 

S*ic*T *« almns, *wr*n "0 rJiifl* end m 

your ught*. bu; don'i w*rt ioa lernfi , 

To help you wnio proorams In Forth •nd 

unrJentand more about in* Jupiter Act 

each canetlej cornet with ful u«ar noiei 

■gmng detaiti of progrem trructure end 

conertrifl apeeriic ppmi* of "«»r*ti A4 

orograrns IK. 

Cttmmt* (3.95«4chAi3ed,8&dv: p&p 

Forth Dimaniktn 

32 Saihunt, Orion OoldHay, 

Partorborough, Camba. 

Tarn your own atftwar* mro metier 

fop ronton p*n/ 

79 r 3 



Teachetiid |1W E3J.».i TeiCntr Paul r4ftK 
£% 20l S0*ctru.m owners use you' macrMne. 
Ciitjiitu, iiauiiic*. grapha. jorti - rank and 
¥ph»bet«a;. genunahr uwlul Mr B. F arris. 8 
ThorvUS*on Road, Bolton Rt,l eOF I Oregon 
venion tvaltbltt. 

ea/a 



FOR ALL YOUR 

SOFTWARE 

UNIQUE OFFER' . BtSl VIC 

SDFTWABE LIBRARY. 
SPECIALISTS (Over 70 Tdo Titles') 
Mire a cats or cart for A TUk. thon, il 
yuu v«Uh 10 buy n keep it and lend uiih* 
cost and we rt.H REFUND VOUR HIRE 
CHARGE) 

ir you decide no! lo keep '1. sirnph/ nrturn 
n and mayha try another pf pur -vuide 
ranoa SQ J0IN 

:rOMCLUB: 

THE CLUB WITH A DlfFERfiNCS 
TODAY AND RECtlVl A8$0LUTELV 

ft, ft I 

COM50FT DRAUGHTS « COMSOFT 

WORDSEARCH CASS, lunex. RHP «!' 
laK-lcK. RRP £81 

PLUS; Spoowl OHets, ctMtip*, and news- 
lollOfll Wrr» NOW W. 

COM CLUB 

24 Alton Road, Ay le sinner, 

Leicester LE2 8QA 

For FREE CATALOGUE, MEMBERSHIP 

FORM. AND YOUR FIRST ORDER 

FOHM 

R EMEM BE R IF ITS GOOD THEN WE 

STOCK IT I H 44/3 



Oisgon 32 - Ffv* tuning gamea only f 4 40, 
Bun* & Outs, R*Ttt»p, tan* 0*f*nce, M*j* 
runner, Hamuratti. Aroani Soflwin Lid. 25 
Lvnwood CHase, Rracknea, B«rti tYCi 

Spectrum Graph PVonar Oriw ye**r own P* 
charts, Bar-eharl3, Lin* Plots and Scatter 
dtaprams wim Eh>s very versatile package ol 
five routine*, fp lor lap* lincludei five 
lutori*l5/pemonitra!ion»| «nd luH dPCu- 
m*niadon o» SAE for doi«ih. Toeoraph 
Software. 101} Olundall Rptd, l,ulon. Bed- 
fordsnir* 47/2 



BROKEN YOUR TV/ 
COMPUTER JOYSTICK? 



Inude taut yaystick herK*« 
« t white ola«ic mum. 
I The main causa of failure. I 
Stronger mser! replacemmit 
now available. Supplied 
with lufi litling m*[rueiipni 
fiowtng you to be back in 
action in seconds 
Send £2- &}; pair 

f&u t^: I Y-Cl 

Computer Suppliae, 

14i Church Road 

8paton, 

Lines PE210JX 



10 3 




Dragon Misarie Cor^rrund DrotHt lh« domed 
city ot Spartia from enemy ICBM's beware oi 
tile deadly radMtion cloud, wperp gi«phics 
F3 » S- Marsh. 18 Lamoerhurst Road. 
Maid*tofte Kant. 

a/a 



ORICI 

CASSETTE LEADS 

Din lo Din & remote : '^-^ 

j*ck plug 

Din to 2 * 3.5mm jacks 

1 x 2-5mm for renvoi* 

PRICE ONLY C 50 

Cash uriTh orders includes o&p 

CLARES 

222 Tnvmljekta Rd. VWrniotd, Cheahm* 

i.VV^4iX r< >V-.A.-]b'J74 

59. J 



Congo 32* BBC Graphical adventure Survive 
crocodaa*. Hdht caAnejab etc, to Find Doctor 
Lrvmosiona E3.9&. O Smith, 73 Madrscn 
«,■•...■ BflU rrsam -ii 



TEACH YOUR CHiLD 



• T*ll >h» Tinm 
and Count Money 

on your Spectrum ItSKI 
Two Fun -firephic:* 
Programs on Cassette 

lor fS.SO inc. O b p- 

V. Sampson, 

Richmond House, 
InoJeton CARtJfOHTH 
LAS3AN 

35 13 




Poppy 

Progromi 



Spectrum lrJJt'efl*;, |hr clai*c 'BafUcships' 
and '{scape From Tha Cry(rt'. g fww adv*0' 
lure oame. Fu" Graphics. Bolh games on on* 
ca aa er ta fo* FB. fl. Acion. 44 Beehive Lane. 
BasMon, Essen. 

IB/3 



SMASH DRAGON 32 ■ ? .'•'■ 

A super "break-out" type game m high 
resolution graphics. Features inckjdc a 
demonsPiDOn mode and w*Ht of in 
trej&mo, diflituity from a snglc wiH up 
10 a full three wails. Connmrours dispfay 
ol icore, best score and balls 
remainkng 

FRUIT A DRAGON 33 ANO 

5PECTRUM4SK f6.50 

A deajxe fruit machine featuhno.:— 4 
uujms. Spin. Ftrapin, HoM, Gamble, 
Collect, -Nudge. Bounce. Band, Cancel 
and Jaclipot. Now drums mm.., 
■sctumd for each game, 

EVlCTORTM DRAGON 37 E7JM 

SP£CTRUM4eic es.go 

A raactivB game with machine coda for 
e*(r« op. Evict ",h« gavna from the* 
self' rv, generating and delended bqse 
Cedfum Lim-i. Phaser and bombe. fi 
skill levels. 
SpOCial Otfat - DRAGON 37 - 
aJtnreefor f 18.00 

SPtCTRUM4BK _ hothlor E 18.00 

All price* incluirvL-. mail otof Only, 
cheques or potlal oidan lo: - WIZARD 
SOFTWARE, P.O. Bon 23, DUN- 
FERMLINE, Frfe. KYll 5RvY. Sond large 
SAE for Pull program catalogue, 
noyriliie* and/or tomirrauori paid for 
»uiwt« owabiy DRAGON v SPtCTRUM 
»oftw«re- 

&££. 



Acorn Atom 1ZK ftAM 1ZK. Rom 8eeKs, 
Sdhwm 8 months old C 1 3S. Tal : Darby IS33? I 
5 14033 

ZXerabbfa t$K ZXS1 vvprd cjam* program, 2<« 
plavers, cassatta E4.50, Atsofi, 18 PosTmsl 
Close, ipswth 1P4 2RF . 

58'3 



ZX SPECTRUM CP48 
32K Memory Extension 

Gives tatel ol 4BK Simply fits internally 
On pnno-i 7 mndn wilh *ic soldering 
Sim i.ii to competitors but only £24.50. 
Fitted by our engieers idon'i »m) 
power supply I L3I.S0- 

CITADEL PRODUCTS LTD 

Deal YC, 50 High St.. Edgwire, 

Middlesex. MAS 7EP 

T»l;01 »l 18*8 



M2B3A Sharp 32K Micro, Software pack, 
Muolc compiler, U it map programs t42S T(H 
Baeingtiolu, (12551 55358. 

») 



WANTED URGENTLY 

Arcade -type games progfames for Spetrtrum, ZX8 T , 

Vic20, Oric, Dragon, BBC Micro and Lynx. 

We pay top royalties or buy your copyright for 

cash. National mail order and dealer sales ensure 

you get the best reward for your geniLis. 

Write or can into 

NORTHWISH LTD 

THE GROUND FLOOR, RAW B4JIIDINGS 
STANLEY STREET, MAIVCHESTER 
M3 SFD 
Of Phone 061-832 9143 ^ — " 

—*k/e Pay J(aAd Ga&U fat, gafauate—J 




1 9 2 YOUFt C QMPUT EH . A PfllL 1 9S3 



Weekend courses in Sinclair Basic, starting February 

1983. 15 hours of instruction from a qualified lecturer, 

Friday evening to Sunday evening. 

Luxurious 3-star Worcestershire Hotel, all rooms with 

bath and other facilities. 

£55.00 inclusive, 

GAINSBOROUGH HOUSE HOTEL 
Bewdley Hill, Kidderminster 

(0562) 754041 ,,, 



TEXAS 

Tl 99- 4A 

CASSETTE LEADS 

MM 

INCLUDING POST 
AND PACKING 

Single Recorder onty 
Order* to: 

Clare*, 222 Tuvmfeld* Road. 

Wmsfofd. Cheshire CW7 4AX 

Trff; Wirtstord 5137-1 




Uin|>un 32 Mete* Program*. Progr ami tin bt 
fully nviged an tfce Dragon 32. For luii detail* 
ar-d ifwtrurtiont fend fl pfcj* 5AE to G. 
Grimwopd, Atteciwoods, 105 Conway ftoad, 
Cohvyn Bay, CUyd 

BeV3 



AT LAST! 

BBC MICRO 

GRAPHICS PAD 

FANTASTIC VALUE! 

A hgh quality, cartridge paper pad 
featuring Graphic*. T«l*»ri[ terMfH *ns 
«14»'dt(|n«<l ullt. Flu i easy itlmrM 
S«mrn|iK» *h«i, AH f Of in incftdbea 
(l M*$5cp6b 

Hermer Computer Products Drpt VC2 

10 Barlow Moor Close. Nor den 

Foehd.l*. U"C( QL12 7ftN 

■/a 



Acorn Atom 12+1Z, COtouir. BBC ftea* 

Bos«J. fonti. Software CISC o.n.c, London 
Am Hcrnthg re h 47549 57/3 



DRAGON 32 AND SHARP MZ80K 
SOFTWARE 

Gint-s Pacii £t SO e*rf> 

Gai-« Pack 1 - Bwylirig. UFO. MurtCh#r, 

G*nw Pack 2 - Race-thaw. Depth 

Cluro*. Msm dot*. Glorious l2th. 

Canyon Bombti 

Garnet P#Ck 3 - Tank Battle, Reaction 

Time Bind Mut. One Man and Hi» Dog. 

Lde. 

Game Pick 4 - Pokei, Pontoon. Roulette, 

OW*. Stock Biokar. 

(Sharp onlyi 

AdVanft/ri Gamer 

0«vil* Triangle - Sl» to Bermuda bul 

bewa'* CI th* Benrajtfa Tfiangla! - £5.00, 

Eanh R«*cuC - Search rhe GeSany tor a rare 

m.ner jl needed for £»i IM survival - £5 00 

King of rhe VeWy - Try to oofltr&l 4 

ShigtfDm end rbr people - £3.00 

Dewrt f**troJ - Find your way aerPM 1 

d*Mn But beware at in inhibitam*! - 

£4.00. 

fdueatmnui 

Melha Tutor - A hi o* Dragn>mme* 

designed to luch malhs 10 Children from 

3-10 yn. - ES.Q0. 

Won? Qua - Find the hidden word* In a 

jumuki ol lettn* - £3 00 

Se*id cheque PG o- $A£ tor dau..t to 

Abacus Software 

30 fthoileigh Ave 

Sharptee Park 

Bolton Btl (PP. 



VfC-20 I una vp*ngJKj| G*TI*i Tape iMe- 21; 

Somber*, Break Out. hlerjfrs. Froggy. Spun 
Gct*4m. BanV Robber. Ai G for £4 &5cr wc. 
P6P F*m Oetven/ from. Sun-aker, 31 H C yl* 
Botrf, Hoyrwlte, Wtfraf, 14? 3AG 

BO/3 



THE MZ 80K 
SOFTWARE LIBRARY 

Cheoa* from 150 titles. Then Include 
inciting A't*dfl i' Adv*ntur» gtmt*. and 
FdnC*[i*n*l ' 9 u jmm apptcHDM. One? 
c-nrv m*mberfnip fee C 10-00. Hire c-^jfr)« 
only 90p per 14 day period. Pti*f your fir*t 
$ g*m#» FREE, Send now for iHugtxaied 
caialogue to: 

The Yorkthirfj Software iltitary 

13 Path Tcp. Pud i ay. 
Wost Yorkihlr*. LS28SBV 

34-3 



BBC USERS? 

ixoiore atl your medet 

Create your own unique Gtjffie't d*pl#in 
witfi the Herm** Graphici Pad, All 
model* piue tetetened phti uw defined 
Ctrl* end command* *>>Mt. y ■> C2.59 
pfeii 65 pence p&F 

Hermes Computer Products 

ID Barlow Mor Cl0$6, 
Norden, Rochdale, Lanes. 
OL12 7RN »3 



BBCi2r: ,r VIC20 IB.5K) 



NtW COMPUTER? Try 6nr cuawileed 
MlTware — tor parar t» apef children I egM 
4-161 «vt*0 wfln.1 W 09 mo™ trian put 
snoot aiiBin 1 

LETTERS iBBC a*M -- eg** *-$: lo»rr> 
die correct way to form letter* with ou 
Mtg»C Penl Teacher checked. Gtait 
gripMct, £H 4S 

1MKOSJ - Be an African Klngl 
Adventure le* egtt lO-Mhril - can yr»u 
beat the vyilet doctor; fS.» 
INVISISLF MAN Co -ord-nerei flarrn 
with good fccwndjnc crjjih.-*, agei 7' 14 

tbJm 

. . aMmoiVll 
Send SAE ftw details: 
Lowmoor Coitaoj JYC7K 
TonfidM. Wellinolan 
Somerset TA2i ML 
7J 0823*? 7117 J 

ae«fefh«t agiitn Computer, pmuttenaout 
doplay of bcmei. ?K*1 ctsKl f* K. Dragon, 
C5.50. Ch«u« w B, Sinunond*. 3 AtflM* 
Wear, Crawley quit HBC 

Out and weight control program lor VIC 20 
and CMEt 64 hetet and aaVaei you on tne beef 
eJ.mming dkt. Cttaede £12. tiitk C17. E. 

Frengoiili*, S4 Holand Rr^d. london W14 
KB- 48/3 

Spectrum Forth on cataatte. Falter than 
Jjfwrar Ace, All etructurei. col»jr, Hl-r«. 
Order ii SP16D (1«! or SP4BD i4fJK) C5.S& to 
Mike Hempion. 7 Hereford Onve, Cltheroe, 
BB7 UP 

B4/3 




DPJU30IHB 
AND B8C MODELS 

W fUQMT SlMULATOfl 

Iwer hw£ hmpwiBH^ in] p'-3M 

■na >^*jutc lltni T*» IK n T «- 
uM 4m CN*ebfl'ft ■Mi l llilt 4*K^fl 

rtea«M shm u tn*** n* "»n 

'nun< ^nn^i^r i mm nt mm m t 
Nm((^u» Ttrira in) 21 m* Oak «« 
guv K e4w *4E*len 4m Aafw ir^ 



j gfcm » ■>» *w« arte tee e* < *~n*> 

P^JffaTiWW 4^'^nyf| pf'*afTf l rBr*j'a1 1 TanVanl JaflPBBBnaBi 

W4 net* *»> eevne it eeet -»J 



OAtC CTp 

•as ' 



way i 

WUH« 



'''I' KD CECD 




OOOOO 

nooo 

OCOOt 
GGGG 1 ■ 



0n G 



OO0O1 



mm 



CLASSIFIED 



OffDEff f DffM 



Clossifled Rotei 

Linao*. 30p p*r word {M<n 13 wcdi) — 
pi ■payable 

t'rjj^e acNerfjievt ifxxdd cUTtp/tlr Ifm lot ft 
prt&rtffed *n 5iOC* C4AM1 J. W*»ne nymtnh' 
counri 4J ^ w&0* W#v»#4ini^*«W»Mftro« 

pint for i( uttd M *A>9tfiS*<n*frl flba Number 
tf rtttbitttl i £3 OQtitt* 

IS pi O V - rolfti p«r ice (Mm Tscc) 

OrirrfnierrliOri E7.00 

Threelnie>rliOfii EA70 

SiKinterHom £6 50 

TWely« Insertions EpOC 

JkwJx idren<sttz stioiAtl ptjutJ* ispttttt 
copy widpt6ttt*br\ ttsw* se*c* b t ftiont 

Method of Poymenl 

Chequer! e»c, should tw mtad* poyatHc 
to Btmneu Prow international Ltd. artd 
cronod 1 encfoaa herewith 
deque PO lor 

E 

Pheoio a«Di! my Aeeau-Vno Bciicioy 

CorrJ'Am^ncofi Eipr*tai'DirWrt Ctub ln1 
Dlbrtoyt 



Pleose Insert the following advertisement In Vour Computer Classified Section 



LINAGE 



£4.60 



£6 00 



£7.50 



£9.00 



£10.50 



£12.00 



£13.50 



£1500 




No. of insertions required [~ "JBox No. required YE5JNO 



HAME fPfae*.HnciuoVu*f«e/*/ 



AOORESS. 



S1C NATURE 



Post 10: 

Cut cut the order torm end return 
together wiut your remittance to: 
Ciauified [Vp*rtm»n(. Vour Compute*, 
Room Mill. Ovedren! HOujf*. The 
Quadrant Simon Suttey SM3 5AS 
101 1 661 3038 



Payment by credit card please state address card is registered 
Dciytimefel.no 



THIS FORM SHOULD BE RETURNED BY APRIL 28 FOR MAY ISSUE PUBLICATION 



Company ffesiyferetf Number: 151537 /England/ flejj-ftfrta Otfict. Qutdrtnt Home, The Quit/rent, Sutton, Surrey SM2 HAS, 



YOUR COMPUTED APRIL 1 983 1 93 




SPECTRUM - TRS80 LV1 
VIDEO GENIE SOFTWARE 



[i;i«Ai Com 


|i|^a»B <PL^I 

■S 


^ \JU[ - j" *~m* 


W' ! ^ 








rJaftfS*atpfjcs«t 
Wfctr*s_ Rfl aeT » 



We offer ■ great Mtocoon of flamei and 
uti*.t>n 'rom marry leading v'lAjro 
iKxati* 4! reduced jjoca* As ■ Special 
affar. uj m(ttnlue* yts- to our foftwen. 
¥« are giving away. **■ afcnoai. t 
*ortw»nj pacfc with ■ auper variety of 25 
tu» length (KOpr«mn»i on rt, and *l lew 
only PSHII Do not n»H out 1 Sand for 
your *uwi*rad ctvptoflu* today. Punt 
encio» an a. i.e. 

SPARTAN SOFTWARE 

DEPARTMENT VC 

9 ColswsU Terrace. 

Clhppnu Norton, 0*on 
Talepooe: -, 0606 SOW 

31/1 



2X91 Fate Load and Save. 4Xi fetter thin 
norma! £5.00. AmaiWio Soltwaie, 3* Aslarwls 
Sale, Manchea f r . 

7,'S 



BBC MOO OWNERS 

Would you Wit your ensiiog BASIC 
p'ograrru to: 

* Take up to $0*4 UnS» i™-™ot 

* l,aat3 no in 60% Iijm 

* Ru n up to 00% fairer 
without buymo more liarttwaref 

Vim f Then you need t-ha Optirraui . 

Th* Op ii rnei a i ■* • two siagfi propam 
compact** atttf variable opIimKei. II rum 

on ■ modal A or B rt nrnllihhfj now on 
camrlte pnc« C* SO inebuike from 

S. Carty. 12 Ekntfane Avenue. 
Homdiwch, Essex RM11 2QH 

M/ivi wdrr gptfi 
a iramoad addrnworl rrri/elope 

43.3 



r> 

for more entail* 



Spectrum »Hw)n Unary. Weekly hire Item 
SGp. Try programme out twfoni you buy. Send 
itimp for free catalogue (■* Thorn** 

McQueen. 25 Blenheim Gdma; firmon HiB. 
London. S.W.2. 

MM 



ATOiVI 

PROGRAM 

AIDS 



[ 



f *» H NH* I KH i VAT. 



] 



.—*- <^. IT 

*4H -C^5* ■* Hi 7|t*t -* rHM Fd 

L-r.i.. .^« 

-««j*>li'>ei ■■ % li AhJUi i 



BTR ELECTRONICS 






Chenufiiy E>MtF No probeim with Alchemy 
Spliware. G (Hoa*onr» each with entjnuve 
note* Covering fottauO*. UCuttalwna lor 
O CSt lot 2xtlt *■« Spectrum Send &AE (Or 
rif laJs 79 TMveend^te* Road, HuS. 

62; 3 



GARLAND COMPUTING 

educational software for 
the BBC and Dragon 

Ohm frn*baj4 you to annulate an 

anpai-lmaflr. to verify Ohm's, 

law. Draopri - f$,00 
Motor learn the principle* ol the DC 

molo*. Dfaocn - - fS.OO- 
Heart loam the enatomy of lh* naaft 

and how Wood flow and 

•hKlnctl jetwrty are ca- 

otdlrujted. 

Driaun - f 11 00 BBC IJJK, 
£11.00. 
Seed nil tr>» atfett* ol vanpuc 

condniorn on f**d 

oerrninjtion. 

BBC i33K> - £1«.0O 
Plui rnany more 
ft»rt* mcbvvm of VAT mats W&P. Sanrf 
f(ri fui tfwtiii at our tmn&w fang* #1 
ntttwtn lot SCftCOi anrf ftewne use. 

GARIAND COMPUTING 
35 Ostai HI, FrfTHHith PU 9AF 

26 .'3 



SPECTRUM 32K RAM - £24-90 

•Jngnda your 16K Sppctrum to 4@K wiih out RAM k(i. Onry fill IMUC- 1 rnachintt, 
identified by * large eh.p in a ^odicri <n line with the "9" key. viiole inrougti the rur 
enpanifln cutpui. The kit uthu of eh!oa and inar/ucuons, and MO soldering: « needed. 

EH.fUlnct. VAT end PUP 

HAPPY WITH VOUR DISPLAY 
Or have yon got probtontt? 

* An your wfiiw yaaowitO? 

» H *v«¥ ott»» ta»» a drfletent colour IHuJ Ve™tjin uandul? 

• Do your characters *aC&H>? 

I Some character ihebble ik bound tfl exial. bul tl can be tnducedl 

vVe have praoarad >natnHrciona to allow any Spectrum to tyw tne b*tt pOafiHrie nMurtw, 

by adjuiting mtsmal connoH. 

Sand £l plum SAE, tStftt /jnee if you onttt sh» RAfAt 

FOUNTAIN COMPUTERS LIMITS 
DarviM Road. Replay, 

ALRtSFORD, SO?4 0BW 

ib/3 



Vic-30. 18K r 8K. 3K fHK^t, CstMIW D*C±, 
Prtnter, JctyMJCk. 6v*r -f2S0 software IfK, 
Viawriter Word ProceHitvg and prog Aid pkga 
rrvinyUrnH , Total ceil around £ 1 ,QW will set 
for f?W ti.n.o. Tat I03u4|i 493429 or contact 
tl?0 Chottay Old Road Botton for th« rjreat 
;■•>".;;' n 

$4 3 



BBC MODEL B 

QUALITY SOFTWARE 
- KEEM PRICES 

DOMORlO 

Unravel the mvitery pattern ol dominon 

created by the computer la new problem 

every timeJ. 

Deceptively 1 nought provoking. 

VVORDGHID 

The computer Md*t yOtu nv**d* in ihn 

wo»d tojuarv - ift*n your opponam hat 

to Mtk them put an line I no primer 

reautfudl 

S*nmbla, Fimily gtmn iwi(h adutatlpn*! 

value. 0.9& fmcl it* pair. 

SAE for lift ol thete and ortier progrenti 

Strawberry Software 
78a Sunderton Lane 
Ctartfield PORTSMOUTH 
POS0NT 13^ 



AppU II »8K. EutopM, brand ne*, PAL card, 
SatiC Compear. Apolewfiltr 11. LS4.I. 30 

game* worrh fSOO, total value fl.SOO, for 
VSSB- 01*H &06I. lata evvningi. 

J1 3 



DEATH'S HEAD HOLE 

V&j'II aimoii believe rl'a tntal 

Hi itufl, courage and: your growing 
wqjanerioi lh*t count tn tha unique 
adventut* lor th* Dr«o«n 3CS and &BC 
Modat B. biapirad by ?ha real-Me 
chaUengea taong a cave rmcuo team. 

L'teranv houn of axcrlement — if you 
rneaaureuo 

AfaN thb, any olfuer ntitvenlura wW.uilbe 

Onry fS 46 by taruiYl Of pott Irom 

WORDS AND PICTURES 

7 Hiwthrtrt Crmeant, 
Burton- on Trent 

4 3 



MUSICSOFT 

BBC MICRO 32X A.'B. 

fj nuic garnet ol memory and dexterity. 
Miinco'our graphfa. Fun for E year oldi 
yet frunrating rbr giaduates. Variable 
■paaxh and Kale levels. Cafuttte and 
Irtttruiriiont Cl.SO 

Cnaqun to Mwcaaft 
12 Ftnowlttld Ampthet Bad*. 

30/1 



Abjcus Compyterg 1 70 

Acorn Computers 1u4r ?05 

ACS Software 130 

Aclrve Softw^fc 27, 1 tjl 

AF Sohwaro 8t 

ALFdoe Electronics 190 

Amb* 7S 

Amorsham Softwar* 118 

Anifc>g tiB 

Apex Trading 63 

Artie CofTrputJrmj 12 
Audio Computers 43. Inside back cower 

Automata 183 

Autofam ITS 



B 

Bade issuw 

Bamtoy Software 

Beaumont Sufner Camo 

ft«? Bug 

Bibi CompAitnrs 

B*wV 

Bridoe Soitwaw 

Buffer Micro 

Bug Byte 

C 

CCC Ud 
CTE Micro 
C.P, Software 
CTeeli 

Caipoc 

CambfitHjif Micro 
Campbell Systems 
Carnell Software 
CascjoV: Software 
Computer Club UK 
Computer? Few All 



170 

l&l 
163 

ice 

i-.-s 

l&l 

S3 

172-173 



!71 

160 

ST 

26 

142 

184 

166 

34 SB 

8 

132 

4 S 



Ecortotcch 1 16 

Educarer 84 

Epsom Micro 139 

F 

Folkade 164 

Fortjil Sohwan? 1 13 

Fox E&cctronies MB 

Furionfl Pstrtf 163 

Fuller Micro 154 

G 

Gfffl Soliware 27 

Gftmmi Mark-tit'.nu 10' 11 

G*mirtt Software 163 

Gifcoll 2? 

H 

H«i«IIW Simon 1G2 

H tNvsort Consultanu 46. 47 

H/H Software 121 

Hilt rjn Comuulcr Services 1 34 

Hi Soft 4£ 

HiTech 121 

I 



DA. Corrrputets 

OTL 

OK Tronic* 

Oownsway Etpctrontcs 

Oragon Data 

OraQon Dungeon {Thai 



130 

92 93. IBB .'159 

142 

146/147 

167 



Imagine Computers 

Impact Software 
Industrial process 

J 

Jaysoft 

JRS Soltware 



Kempslon Micro 
Kuma Computers 

L 

Laserbug 

Leisure Mail 

Luon Noel 

LevfH9 

LoKonics 

Uarnasoft 

lolnctrianlMU 



20/21,22/23, 

24/25. bade cover 

90 

IOC 



106 
150 



91.165 
120 



1S2 
63 

165 
« 

121 
71 

n6 



M 

Malva 

Maptin 

Medway Computem 

Melbourne Hous« 

Mamorach 

Micro Aids 

Micro Business. 

Micro Ocfll 

Micro Game Simulation* 

Micro Management 

Micro Mania 

Mico Scene 
Midland Computet Fair 

Mtkto G4n 

Morrison J 

MST 

Myrmidon Software 

N 

National ZX Club 

New Generation 

Neptune 

fcewne* Technical ftra5ks 

NewstKh 

Nnrthw-sh Inside 

O 

Oakleaf Computers 
Oasis Software 
Oric Computers 



Personnel Computer Service 
Ptwpps Associa tes 
Pictured ue.- Addiciive Games 
Print and Ptottct 
Ptogram Power 
Pro Software 

P.S.5 

Q 

Quark Dais 
Quicksilva 

R 

RDLafes 

Redcfitcri Compuiers 

Richard Shepherd 

Ros* Cassettes 



116 

71, 156/157 

167 

106/109 

18bV1B7 

145 

124 

13 

160 

54; SS 

136 

76 

191 

134 
184 
136 
132 



62 
188 
161 

73 

179 

From Coyer 



S 

5*1*1 andr, • 

Samuari 
Sci Sof 

Severn SotlwSre 

Silver Soft 

Simon Soft 

Simon Software 

Shard's Software 

Silica Shop 

Sir Computers 

Soltek 

Software Supermarket 

Speciure 

Spectrum 

Stuan William* 

Sloneship 

Siork Rose (D»ta Amelia] 
Subs Frlter 

T 

Tangerine Computer 

Teunan 

Timedata 

Tr«n4form 



16$ 

9 

136 

146 

44 

90 

118 

45 

9 

75 

52, 180. 186 

135 

189 

14, 15. 16,17 

70 

18. 148 

126 



168 
IBS 
113 

134 



118 

168 

174/175 

182 
38 

132 

125 

32.163 

78 

140 

171 
58, 113 

150 
120 
110 
121 



U 

UTS 63 

V 

Vacl is Software 161 

V * H Computer Service 102 

Vtcia Ceramic* 1 16 

Viking Software 142 

Vugin Games 154 

Vis»ori Store 169 

W 

Warp Factor 8 166 

Words and Pictures 160 

Workforce 136 

Winter Software 130 

Wireless World 169 

V 

Vewacre (Micro Compute* Software 

Club) 94 

Youth Hostel Association 71 

2 

2XSAS 130 



194 VOUR COMPUTER. APRIL 1983 



FIRST STEP FIRST TO A REAL SYSTEM 




EPSON 




FIX-A-RAM OFFER 



'V 







STOP THE RAMPACK 
WOBBLING 



for only 



£0.50 



post and packing included 



Program crashes on the ZX81 are only too well known, but one of the most 
common reasons is 'wobbling' . 

The Sinclair Ram Pack is attached to the computer by a small contact area, as 
shown in figure 1. 

We have designed what is much needed: aplastic sleeve, which is sandwiched 
« discreetly between the Ram Pack and the computer, called the FIX-A-RAM (see 

! % 2). 
RESULT: a perfect match and stability. 

iY^mcomgtiter may still crash, but certainly not due to 'wobbling'. This example 
csfiowTfiow we work to enhance the ZX computer system. We put the right thing 
in the right place and sell it at the right price. 

To find out more about what we make for the ZX81, why not send in for a 
JFDC-A-RAM? We will send it to you by return, together with THE LIST — full 
details of our hardware and software for the ZX81. Please remember f details will 
only accompany the FIK-A-RAM. 

EXTRACT FROM THE LIST 



Fig. 1 



dk 



•1 



*- ■* I 



Aiit, start Rom 



Utility Horn 



Application Rom 




v\ 

c r 



- "CALO the giant electronic spreadsheet: up to 43 k of (am. 
Chip: £19 95 or Tape; £14,95. 

- - EDASM* the full editor assembler- ChiponUj: £19.95. 

- Games chips from £4.95. 

- XROMCARD (as illustrated): links up to EPSON 
printer, programs EPROMS from tapes or chips A 
with built-in machine code monitor. £17.95. JgQ 

- X ROMCARD II: enhanced version of the 
X-ROMCARD with Hi Res (256 x 192) 
moving graphics. Extended BASIC, 
amplifier speaker, joystick socket 
(for ATARI joysticks) DRAW 
pictures with joystick etc. jk 



Printer S ocket] 
Joystick! 



Printer Cabki 



[ANATOMY Or THE X-ROMCARO; 












Imogine Software, Masons Buildings. Exchnnge Street East, Liverpool Merseyside 12 3PN. Telephone: 05' -2360407 
1 l4J *=5 o / 



trrtiimttttinit)itiiti\ui nitmiiiimmmUtmiu 

////'/ WWW 





ATARI 800. No price increase. Upgraded from 16K to 



48K RAM. 




ATARI 400. Reduced from £199.99 (S.R.P inc. VAT) to 



£159.99. 



*#, 



GAS 



isv: 




'■THLY CHIT! ttVl 



'////S/'f/S 



ih**pwM 



O ATA/8 a© i 




At prices like these, they m 

Here's a cl 



From today, we've upgraded the 
ATARI 800 to 48K, but we haven't upped 
the price by a penny It's still £399.99. 

As for the ATARI 400 it's reduced by 
arou nd £40. Now take a closer look. 

ATARI 300 and ATARI 400. 
The straight facts. 

Computer console: FCC approved, with 
built-in RF modulator Connects to any standard 
colour or black & white TV 

Colour; Choose from 16 colours, and 16 
intensities. 

Sound: Four independent sound synthe- 
sisers for musical tones or game sounds. Four 
octaves. Variable volume and tone for 
each channel. 

Display: Three text modes: 24 lines of 



40 characters; double-width characters. Nine 
graphic modes: from 40 columns by 24 rows 
up to 320 columns by 1 92 rows. 

Keyboard: 57 alphanumeric keys plus 4 
special function keys. Inverse video. Upper/ 
lowercase 

Full screen editing. Four-way cursor control. 
29 graphics keys. Full stroke keyboard (ATARI 
800} and mono panel keyboard (ATARI 400) for 
fast, easy data entry and interaction wrth the 
computer; 

I/O: Serial input/output port for simple 
connection to peripherals. Four controller jacks 
for joystick and paddle controllers. 

Memory: Includes a built-in 10K Read 




ust be worth a closer look, 
loser look. 



Only Memory (ROM) Operating System with 
48K Random Access Memory (ATARI 800) 
and 1 6K Random Access Memory (ATARI 400). 
ROM may be expanded with user-installed 
cartridge programs. 

CPU: 6502B Microprocessor 0.56 micro- 
second cycle. 1.8MHz. 

Language: Atari BASIC Cartridge is i nclud- 
ed with ATARI 800, Also programmable in Atari 
Microsoft BASIC.PILOT PASCAL, extended Fig, 
Forth and assembly language. 

Monitor: With the ATARI 800, if desired, a 
monitor jack allows composite video output for 
connection to a colour or black and while 
monitor (in addition to a standard television set). 



Owner's guide: Atari BASIC Self-Teaching 
Guide and Atari BASIC Reference Manual 
included with ATARI 800. 

Extended graphics functions: 
Hi-resolution graphics. Multi-coloured charac- 
ter set. Software screen switching. Mixed text 
and graphics modes. 

Multiple redefined character sets. Player 
missile (sprite) graphics. Fine screen scrolling 
in any directioaChangeable colour registers. 
Smooth character movement. 

Software: Self-teaching programs with 
the unique voice-over. Home Management. 
Education. Programming aids. 

And of course Atari's famous entertain- 
ment software 

Peripherals: A complete range of periph- 
erals and accessories that are available now. 



Why you'll feel more at home with 
our computers. 

Before we designed our computers, we 
thought about who was going to use them. 

One day our computers might be playing 
games; next, they're wrestling with household 






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budgets; teaching geography to an 8-year-old; 
or printing 2,000 letters. 

I n other words, we designed our computers 
and software for as many applications as afamily 
has ideas 

. (Now'the ATARI 800 has 48K RAM, there's 
even more memory for even more applications.) 

Next, we built in high-resolution graphics. 
Inside our computers, we have a microprocessor 
whose only job is to operate our graphics. 

(All told, you can choose up to 1 6 different 
colours from a spectrum of 256 different shades,) 

In fact, Atari computers divide the screen up 
into 60,000 ti ny points, each one of which can be 
changed without affecting the other. 

On screen, you can even blow up a line of 
type to quad size {invaluable if you're teaching a 
child to read). 

We also looked at ways to make computers 
rather friendlier. 

On the ATARI 400, we've incorporatedtoucfv 
sensitive keys with ridges, so fingers won't slip; 
on the ATARI 800, we have keys much as you'd 
find on a standard typewriter. 

You talk to your computer in a choice of 
languagesjncludingATARIBASICusingsoftware 
which you load in on cartridge, cassette, or disk 

At Atari, we have one of the largest software 
Hbrariesintheworld(someofourcurrenttitlesare 
on display on this page). 

No doubt you know all about our games, 
but we also boast home and office application 
software as well as educational programs to satis- 
fy the most enquiring mind. 

At the same time, through Atari's Program 
Exchange (APX), you can have access to a wide 
range of the most imaginative programs written 
by our users. 

Or you can learn to write your own programs 
with the help of our Invitation to Programming'™ 
series, using our unique 'sound through' system. 

Surprisingly you won't have 
to plough through a small library 
of manuals to do so, since most 
of the series is on software, not 
in hard books. Of course, we've 
always had just about 
everything you're looking 
for in computers. 

From today we've 
got even more. 

Home computers you'll 
feel at ho me with. 

"are trademarks of Atari inc.* ATARI and de&fln.R&g. in UK. 




ATARI