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JANUARY 1981 Vol. 6, . 
$2.50. in USA/SS.95 Th Canada 

• A McGra^-Hyi Publication 







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HAND-HELD COMPUTERS 



YOUR CHOICE-smart either way 

• Over 140 software driven functions 

• 82 x 24 or 82 x 20 screen format — software selectable 

• High resolution 7x12 matrix characters — P-31 green phosphor 

• Upper/lower case character set — plus graphics character set 

• 56-key alphanumeric keyboard — plus 12-key cursor, numeric pad 

• Internal editing functions — insert, delete, scroll, roll, slide, etc. 

• Parallel printer I/O port 

• 50 to 38,400 baud operation — programmable 

• Cursor type, cursor position, print control characters, protected fields, 
shift inversion, dual intensity and many other features 

8212 — twelve-inch diagnonal screen or 8209 — nine-inch diagnonal screen 




SOUTHWEST TECHNICAL PRODUCTS CORPORATION 

219 W. RHAPSODY 

SAN ANTONIO, TEXAS 78216 (512) 344-0241 



Circle 338 on inquiry card. 



Gromemco accepts 

your challenge, 

Data General 



Yes, Data General, we saw your 
ad. 

So we realize you hope to win 
over some of our computer 
business. 

And we can see you have reason 
to be pleased about your line of 
minicomputers. They are MINIs 
though. 



But Cromemco produces state- 
of-the-art MICROcomputers. 

Powerful ones. 

And our micros have some 
outstanding advantages. 

For example, Cromemco is the 
only microcomputer manufacturer 
to support a broad range of 
microcomputers with (a) 5-inch 



WE' ISTIN0 

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Announc'ins.'. MIK', 



1 MBC/3, 
' Data 



i A/A ' board computers. 
■ ■ the best computers on a 
board money* an buy. Vou getup 
to 64K bytes of memory, serial 
rind parallel I/O lines, ^.: 
■ pi ;r» from MP/OS, 
our famous micro operating 
system. You oven get supporting 
like MP/PASCAL and 
for \ ourseif. 



<aa 



Reproduced from the 
July 31, 1980 issue of 
Electronics magazine. 



stition will , 




■ .-.. ■ fction I " • 












double-sided, double-density floppy 
disk drives and with (b) 8-inch 
double-sided, double-density floppy 
disk drives AS WELL AS (c) 8-inch 
Winchester hard disk drives. 

That means, of course, that our 
customers have a wide choice of 
disk storage capability. 

UNEQUALLED 
SOFTWARE SUPPORT 

OK. That was one point. 

Here's another: our stunning 
selection of software support. 
Cromemco is the only micro 
manufacturer to produce both 
single-user and multi-user multi- 
tasking computers with software 
like this: 



SYSTEM SOFTWARE 

CDOS (a CP/M-like operating 

system) 

CROMIX (a UNIX-like operating 

system) 

RPG-II (IBM-compatible) 

COBOL 

BASIC 

FORTRAN IV 

RATFOR 

LISP 

C 

Macro Assembler 

APPLICATION SOFTWARE 

Word Processing System 
Data-Base Management 
General Ledger 
Accounts Receivable 
Accounts Payable 
Inventory 

All of this is available now with 
more coming all the time. 

So there you are, D.G. 

You can see why we know our 
microcomputers will stand the test. 

Cromemco eagerly accepts the 
challenge. 



Cromemco logo on 

computer board shown 

in original ad 



Circle 1 on inquiry card. 




Cromemco 

incorporated 

Tomorrow's Computers Today 

280 BERNARDO AVE. MOUNTAIN VIEW, CA 94043 
(415) 964-7400 • TWX 910-379-6988 



BYTE January 1981 









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Hr.count* Payable 




Management Information Display 



Ultrasonic heart sector scan 



High-resolution display with alphanumeric^ 



Get the professional color 

display that has 
BASIC/FORTRAN simplicity 



LOW-PRICED, TOO 

Here's a color display that has 
everything: professional-level resolution, 
enormous color range, easy software, 
NTSC conformance, and low price. 

Basically, this new Cromemco Model 
SDI* is a two-board interface that plugs 
into any Cromemco computer. 

The SDI then maps computer display 
memory content onto a convenient color 
monitor to give high-quality, high- 
resolution displays (756 H x 482 V pixels). 

When we say the SDI results in a high- 
quality professional display, we mean you 
can't get higher resolution than this 
system offers in an NTSC-conforming 
display. 

The resolution surpasses that of a color 
TV picture. 

BASIC/FORTRAN programming 

Besides its high resolution and low 
price, the new SDI lets you control with 
optional Cromemco software packages 
that use simple BASIC- and FORTRAN- 
like commands. 

Pick any of 16 colors (from a 
4096-color palette) with instructions like 
DEFCLR (c, R, C, B). Or obtain a circle of 
specified size, location, and color with 
XCIRC (x, y, r, c). 



•U.S. Pat. No. 4121283 




Model SDI High-Resolution Color 
Graphics Interface 



HIGH RESOLUTION 

The SDI's high resolution gives a 
professional-quality display that strictly 
meets NTSC requirements. You get 756 
pixels on every visible line of the NTSC 
standard display of 482 image lines. Ver- 
tical line spacing is 1 pixel. 

To achieve the high-quality display, a 
separate output signal is produced for 
each of the three component colors (red, 
green, blue). This yields a sharper image 
than is possible using an NTSC-composite 
video signal and color TV set. Full image 
quality is readily realized with our high- 
quality RGB Monitor or any conventional 
red/green/blue monitor common in TV 
work. 




Model SDI plugs into Z-2H 11-megabyte 

hard disk computer or any Cromemco 

computer 

DISPLAY MEMORY 

Along with the SDI we also offer an 
optional fast and novel two-port memory 
that gives independent high-speed access 
to the computer memory. The two-port 
memory stores one full display, permit- 
ting fast computer operation even during 
display. 

CONTACT YOUR REP NOW 

The Model SDI has been used in scien- 
tific work, engineering, business, TV, 
color graphics, and other areas. It's a 
good example of how Cromemco keeps 
computers in the field up to date, since it 
turns any Cromemco computer into an 
up-to-date color display computer. 

The SDI has still more features that 
you should be informed about. So contact 
your Cromemco representative now and 
see all that the SDI will do for you. 



Circle 1 on inquiry card. 



G 



Cromemco 

incorporated 

280 BERNARDO AVE., MOUNTAIN VIEW, CA 94040 • (415)964-7400 

Tomorrow's computers today 



In The Queue 



Volume 6, Number 1 



January 1981 



Features 

1 8 An Introduction to Atari Graphics by 

Chris Crawford and Lane Winner / Learning to use 
the Atari display list can help to unleash the full power 
of Atari's custom LSI video integrated circuits. 

34 The Panasonic and Quasar Hand-Held 
Computers: Beginning a New Generation of 
Consumer Computers by Gregg Williams and Rick 
Meyer / This full-function computer fits in your hand 
and weighs 14 ounces. 

4"0 Electromagnetic Interference by Steve 

Ciarcia / Interfering electrical noise must be dealt with 
according to its mode of transmission. 

7 2 The NEC PC-8001 : A New Japanese 

Personal Computer by Michael Keith and C P 

Kocher / This popular Japanese personal computer may 
soon be sold in the United States. 

1 48 Generating Bar Code In the Hewlett- 
Packard Format by Thomas McNeal / Bar code pro- 
vides a cheap, easily reproduced, mass-storage medium 
that encourages the publication of software. 

226 The Picture-Perfect Apple by Phil Roybal 
This driver software allows your printer to transcribe the 
high-resolution graphics of the Apple II personal com- 
puter. 



Micrograph, Part 3: Software and 
Operation by E Grady Booch / Part 3 concludes this 
series with a description of Micrograph's powerful soft- 
ware and instruction-set usage. 

318 Whose BASIC Does What? by Teri Li 

Knowing the differences between the six most popular 
BASICS is essential. 



Reviews 



94 The Sinclair Research ZX80 by John C 
McCallum 

1 18 The HP-41C: A Literate Calculator? 

by Brian P Hayes 

208 The Newest Sargon — 2.5 by John 
Martellaro 

216 The SwTPC 6809 Microcomputer 

System by Tom Harmon 



Nucleus 



6 Editorial: Hand-Held Computers 
10, 292, 314 BYTE's Bits 
12 Letters 
90 Technical Forum: SC/MP 

Instruction-Set Summary 
104 Education Forum: Multi-Micro 

Learning Environments 
1 42 Desk-Top Wonders 
182 Systems Notes 
188 Languages Forum: A Bug in 

BASIC 
200 BYTELINES 
282 Ask BYTE 
294 Software Received 
296, 298 BYTE's Bugs 
298 Books Received 
300 Book Reviews 
304 Event Queue 
312 Clubs and Newsletters 
328, 334 Programming Quickies 
336 What's New? 

382 Unclassified Ads 

383 BOMB, BOMB Results 

384 Reader Service 



BITE 




Page 34 



Page 48 



Page 72 



Page 104 



January 1981 © BYTE Publications Inc 3 



lim 



Editor in Chief 
Christopher Morgan 

Technical Editors 

Richard S Shuford; Gregg Williams; 

Curtis P Feigel; Harold Nelson; 

Stan Miastkowski; Kevin Cohan; Bruce Roberts; 

Charles Freiberg, New Products; Steve Ciarcia, 

Mark Dahmke. Consulting Editors 

Copy Editors 

David W Hayward, Chief; Faith Hanson; 
Warren Williamson; Robin M Moss; 
Anthony J Lockwood 

Assistants 



Faith Ferry; Debe Wheeler; 
Karen A Cilley; Jon Swanson 



Production 

Nancy Estle. Director; Christine Dixon, 
Asst Director; Wai Chiu Li; 
Holly Carmen LaBossiere; Deborah Porter; 
Sherry McCarthy, Chief Typographer; 
Debi Fredericks; Donna Sweeney; 
Valerie Horn 

Advertising 

Thomas Harvey, Director; Ruth M Walsh; 
Marion Gagnon; Barbara J Greene; 
Rob Hannings 

Circulation 

Gregory Spitzfaden, Manager: 
Andrew Jackson, Asst Manager; 
Agnes E Perry; Barbara Varnum; 
Louise Menegus; Melanie Bertoni, 
Dealer Sales 

Marketing 

Jill E Callihan, Special Projects; 
Laura Hanson 



Controller's Office 

Daniel Rodrigues, Controller; Mary E Fluhr, 
Asst Controller; Karen Burgess; Jeanne Cilley 

Traffic 

Mark Sandagata; N Scott Gagnon 

Receptionist 

Jacqueline Earnshaw 

Publishers 

Virginia Londoner; Gordon R Williamson; 
John E Hayes, Associate Publisher; 
Cheryl A Hurd, Publisher's Assistant 



Officers of McGraw-Hill Publications Com- 
pany: Paul F McPherson, President; Executive 
Vice Presidents: James E Boddorf, Gene W 
Simpson; Group Vice President: Daniel A 
McMillan: Senior Vice President-Editorial: Ralph 
R Schulz; Vice Presidents: Kemp Anderson, 
Business Systems Development; Stephen C 
Croft, Manufacturing; Robert B Doll, Circulation; 
James E Hackett, Controller; William H Ham- 
mond, Communications; Eric B Herr, Planning 
and Development; John W Patten, Sales; 
Edward E Schirmer, International, 

Officers of the Corporation: Harold W 
McGraw Jr, President, Chief Executive Officer 
and Chairman of the Board; Robert F Landes, 
Senior Vice President and Secretary; Ralph J 
Webb, Treasurer. 



..■..■- ;-V-V-^ 



In This Issue 

This month's cover photograph by Ed Crabtree highlights 
three examples of a new phenomenon in the personal com- 
puter field: the HHC (hand-held computer). Shown are (from 
top to bottom): the Panasonic HHC; the Quasar HHC; and the 
Radio Shack HHC. All three units are discussed in this issue. 
Other articles this month describe two other miniature com- 
puters: the Sinclair ZX80 and the Hewlett-Packard HP-41C. 

Elsewhere in this issue, Steve Ciarcia describes electro- 
magnetic interference; we describe some of the exciting capabil- 
ities of Atari graphics; and We review an intriguing new 
Japanese computer: the NEC 8001; plus a new regular section 
of hardware and software reviews. 



BYTE is published monthly by BYTE Publications Inc. 70 Main St, Peterborough NH 03458, a wholly-owned 
subsidiary of McGraw-Hill, Inc. Address all mail except subscriptions to above address: phone (603) 924-928 1 . Ad- 
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and sales should be remitted in United States funds drawn on a US bank. Printed in United States of America. 

Address all editorial correspondence to the editor at BYTE, POB 372. Hancock NH 03449. Unacceptable 
manuscripts will be returned if accompanied by sufficient first class postage. Not responsible for lost manuscripts or 
photos. Opinions expressed by the authors are not necessarily those of BYTE. Entire contents copyright © 1 98 1 by 
BYTE Publications Inc. All rights reserved. Where necessary, permission is granted by the copyright owner for 
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Office hours: Mon-Thur 8:30 AM - 4:30 PM, Friday 8:30 AM - Noon, Eastern Time 



NATIONAL ADVERTISING SALES REPRESENTATIVES: 



NORTHEAST (617) 444-3946 

Hajar Associates 
280 Hillside Ave 
Needham Heights MA 02 1 94 

NORTHWEST (415) 964-0706 

Hajar Associates 
lOOOEIwellCt, Suite 227 
Palo Alto CA 94303 



MIDWEST (312) 864-3467 

Hajar Associates 
2405 Lawndale 
Evanston IL 60201 

SOUTHWEST (714) 540-3554 

Hajar Associates 
3303 Harbor Blvd 
Suite K-4 
Costa Mesa CA 92626 



MID ATLANTIC (212) 682-5844 

Hajar Associates 

52 1 Fifth Ave 

New York NY 10017 

SOUTHEAST (305) 886-7210 

Hajar Associates 
1 220 Prairie Lane 
Apopka FL 32703 



January 1981 © BYTE Publications Inc. 





■ COLOR 
GRAPHICS 
■ IT'S HERE 




8455-D Tyco Road 

Vienna, Virginia 22180 

(703) 827-0888 

TWX: 710-831-9087 

OEM/Dealer inquiries invited 



Circle 2 on inquiry card. 



Circle 3 on inquiry card. 



UCSD 

PASCAL 
FORTRAN 



Portable 

Develop on a ZSOt, 
runonLSI-11t, T. I. 990, 
6800 or vice versa 

Efficient 

Structured, readable 
Speeds development X5 
Easy maintenance 

Powerful 

Full standard Pascal 
or ANSI '77 FORTRAN 
plus extensions. 
Concurrency, multiple 
users soon. 

Cost-Effective 

Complete system with 
compiler, editors, inter- 
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utilities from $350. 



NOW AVAILABLE 

Operating System 
Compilers 
Programmer Utilities 
Data Base Management 
Word Processing 
Business and 

Medical Software 
Games, Home & Hobby 



Popular Micros 
Supported 

DEC, Radio Shack, Apple, 
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and others 



PCD 



SYSTEMS 



P. 0. Box 143 
Penn Yan, NY 14527 
315-536-3734 



*TM Univ. of Calif. 

tTMofZllog 

ITM of Digital Equipment 

§TM Digital Research 




Editorial 



The Hand-Held Computer 



Chris Morgan, Editor-in-Chief 

There's a new trend in personal computing today — the HHC (hand-held 
computer). For years computer aficionados have dreamed of a computer small 
enough to fit in one's pocket, yet powerful enough to do the sorts of jobs that 
full-size microcomputers do today. 

Amazingly enough, the dream is coming true. There are now no less than 
four models (the Radio Shack/Sharp, the Panasonic/Quasar, the Hewlett- 
Packard HP-41C, and the Sinclair ZX80) that fall roughly into the ultra-small 
computer category. One might quibble with calling the HP-41C a "computer" 
rather than a programmable calculator, but it has all the necessary elements to 
qualify: memory, processor, I/O (input/output), and a full line of peripherals. 
Each of these computers is discussed in this issue. 

Among the new crop of HHCs, the Panasonic /Quasar (reviewed on page 
34) is perhaps the most impressive in terms of engineering innovations; it 
sports some features that many full-size personal computers don't have, such 
as the ability to run for long periods from battery power alone — an impressive 
achievement when you realize that the unit uses, not a CMOS (complementary 
metal-oxide semiconductor) processor, but a standard 6502! It also has such 
niceties as user-definable keys, a built-in real-time clock, uninterruptible 
storage of user programs, and the ability to produce color images on a color 
television (with the addition of an optional interface unit). 

The Radio Shack HHC has its own attractions, including its (relatively) low 
price of $250 and its surprisingly complete BASIC interpreter. The first time I 
saw the Radio Shack unit was at the West Coast Computer Faire last spring, 
where it was being shown in its original form from Sharp. I was intrigued, but 
I quickly concluded it was just a passing fad. Not until I used the computer at 
length did I begin to realize its potential. Here was a machine capable of run- 
ning complex BASIC programs — and it was truly portable! (I have to admit 
that a lot of the fun connected with these units is taking them out of one's 
pocket and showing them to noncomputer people.) 

What about the practical considerations of typing programs on such a tiny 
keyboard? Well, at first it felt awkward, but I quickly adjusted to it. (The 
Panasonic/Quasar is a bit better in this regard, because the keys are spaced 
more widely apart.) 

Speaking of attractive prices, the Sinclair ZX80, for $200 or so, has its own 
appeal. Strictly speaking, it's not a hand-held computer because it uses a 
separate AC adapter. Still, it's tiny and can be easily transported. It has 
become an overnight sensation in England. As our review on page 94 points 
out, the ZX80 has some bad characteristics, such as screen blankout during ex- 
ecution of programs. Even so, a student or other beginner in computer pro- 
gramming could learn a lot with this machine in conjunction with its introduc- 
tory BASIC book (included in the purchase price), which seems to be very 
good. 

Why all the sudden interest in miniaturization? In part, it's the logical 
culmination of the never-ending battle to put more and more capability into 
less and less space. Combine that with the recent Japanese trend toward 
miniature hi-fi components, and you begin to see the driving forces involved. 



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For reliable data storage, 
I recommend systems with 
Shugart disk drives! 



"" Tom Knight, President— 

Nycom, Los Altos, California 



"The last thing you need when you put 
your personal computer or small business 
system to work is a disk drive that you 
can't rely on. If the drive quits, your 
system is out of business!' 

That's why more and more manu- 
facturers and dealers depend on Shugart 
disk drives for reliable data storage. These 
professionals don't want disk drive prob- 
lems any more than you do. Shugart has a 



large family of drives, too— in all sizes and 
capacities to suit your system storage 
needs. For the smaller system, the original 
5'/4-inch Minifloppy '* stores 250 to 500 
kilobytes (single or double-sided)— thatfs 
about 50 to 100 pages of printed material. 
Our single and double-sided 8-inch 
floppys store 800 to 1600 kilobytes. And 
for systems that need a larger data base, 
our 8-inch or 14-inch fixed disk drives 



store from 5 to 58 megabytes. No other 
manufacturer offers such a wide variety of 
disk storage for personal computer and 
small business systems. 

Word processing, general business, 
accounting— big system or small, you can 
rely on Shugart drives. We're known as the 
Headstrong company for good reason. 
We're Headstrong about reliability, quality, 
and value. Ask your dealer. He knows us. 



TM— Minifloppy is a trademark of Shugart Associates. 



Rely on the 
Headstrong Company. 

%AShugart 

475 Oakmead Parkway, Sunnyvale, California 94086 



Editorial 

The Japanese are going to continue to assert themselves in 
the personal-computer market with both large and small 
personal computers. Seiko is rumored to be working on a 
hand-held computer to be released later this year — and 
that will be just the beginning, our sources tell us. In- 
terestingly, Commodore had until recently been planning 
to market a hand-held computer, but abandoned the plan 
to concentrate on the new VIC 20 color computer. (We 
saw this $299 (!) unit recently, and will be reporting on it 
soon. The color quality is remarkable for the price.) Look 
for additional entries into the hand-held-computer 
market from US companies later this year. 

Miniature Intelligent Terminals 

One of the most important trends now going on behind 
the scenes is the pocket-size intelligent terminal being 
developed by Bob Doyle and Jeff Rochliss. The unit, call- 
ed the Microterminal, will be battery operated and the 
size of a pocket calculator. It will contain an intelligent 
terminal with single-line liquid-crystal display, a modem, 
a repertory dialer, and a printer. With this unit (which 
will probably retail for under $300), the user can plug in- 
to any modular phone jack and access data bases all 
around the country, pay bills, get news, send and receive 
messages, and so on. The implications of this technology 
are enormous. We'll have a full report on this unit in an 
upcoming issue of BYTE. 



Our New Look 

You may have already noticed some of the layout and 
design changes in this issue of BYTE. It's all part of our 
continuing effort to make the magazine easier to read and 
more useful to our readers. The major change is the addi- 
tion of a new section in the magazine devoted to hard- 
ware and software reviews. This is in response to our 
reader surveys that show your increasing interest in the 
many new products flooding the market. This new sec- 
tion will give you a variety of unbiased, detailed reviews 
each month. 

We have redesigned the table-of-contents, or "In The 
Queue," page to make room for the additional new mate- 
rial. We have not decreased the number of articles. They 
will continue to be the mainstay of BYTE, as will the 
many popular features in the "Nucleus" section. We have 



Articles Policy 

BYTE is continually seeking quality manuscripts written by indi- 
viduals who are applying personal computer systems, designing 
such systems, or who have knowledge which will prove useful 
to our readers. For a more formal description of procedures and 
requirements, potential authors should send a large (9 by 1 2 inch, 
30.5 by 22.8 cm), self-addressed envelope, with 28 cents US 
postage affixed, to BYTE Author's Guide, POB 372, Hancock NH 
03449. 

Articles which are accepted are purchased with a rate of up to 
S50 per magazine page, based on technical quality and suitability 
for BYTE's readership. Each month, the authors of the two 
leading articles in the reader poll (BYTE's Ongoing Monitor Box or 
"BOMB") are presented with bonus checks of $100 and S50. 
Unsolicited materials should be accompanied by full name and 
address, as well as return postage. 




PASCAL/Z - Q.E.D. 



Ithaca Intersystems PASCAL/Z is the most powerful CP/M™ 
compatible Z-80™ Pascal compiler ever . . . and here's why: 

PASCAL/Z generates true Z-80 native code - ROMable 
and re-entrant — 5-1 OX faster than P-code interpreters; 
permits separate compilation; supports Direct File Access 
and variable length STRINGs; utilizes fast one-pass recursive 
descent organization; the macro-assembler generates 
relocatable object modules; and much, much more. 

Complete package includes compiler, macro-assembler, 
linker/loader and source for the full library on one disk; with 
free copy of Jensen/Wirth book and complete documenta- 
tion. Only $395.00. 

IT'S DEMONSTRABLE! 
Don't just take our word for it. Ask for a demonstration of 
these features and more today at Computerland® and other 
full-service computer stores. 

Ithaca Intersystems Inc., 1650 Hanshaw Road 

P.O. Box 91, Ithaca, N.Y. 14850. Phone (607) 257-0190 

Computerland is a registered trademark of Computerland Corporation. 

CP/M and Z-80 are trademarks of Digital Research Corp. and Zilog, inc. respectively 

PASCAL/Z and InterSystems are trademarks of Ithaca Intersystems Inc. 



^TM 




8 January 1981 © BYTE Publications Inc 



Circle 4 on inquiry card. 



Ithaca Intersystems Inc. 

Micros for bigger ideas. 




Outside of the garden 
you need a computer that can grow. 



For the average garden-variety home and hobby operation, 
a high quality personal computer is a real temptation. But 
let's face it: in the world of business, engineering and 
scientific applications you need a system that can keep up 
with bigger ideas. 

Bigger ideas today mean the power and flexibility to 
move the micro up to and beyond the level of yesterday's 
minis. More memory to hold bigger data bases. More 
flexibility to handle a variety of data entry devices. More 
programming and computing power for numbercrunching 
and applications development. And easy upgrade to 16 bit 
operation when you need it. 

Intersystems has that, and more. The power and flexibility 
of the versatile S- 100 bus, with 20 slots of expandability for 
up to 16 individually-addressable DMA devices and up to 1 
Megabyte of memory, fully accessible to all users via our 
unique memory management system. Plus reliable 
Intersystems design and manufacture, and the support of 
our PASCAL/Z T "...the most powerful Z-80 ,M compiler ever. 

For really serious computing, our front panel provides a 
powerful diagnostic tool for debugging or development. 
Combined with a scope, it allows you to look at any location 
in the circuitry, set breakpoints, trigger and view one-shot 
events, and many other activities usually possible only with 
expensive logic analyzers. No wonder it's fast becoming the 
tool of choice for repair technicians and custom hardware 
designers. 



Intersystems Series II is the most complete line of fully 
IEEE 696 compatible S-100 boards.. .easily upgradeable to 
our MPU 8000™ or other 16 bit S-100 CPU's as they become 
available.. .so you're never locked out of rapid expansion, or 
locked into obsolescence, by dependency on a proprietary 
product line. 

So if you've left those garden-variety applications behind, 
come to Intersystems and get a system that will grow as big 
as your next idea. Get it from the people who know small 
computers.. .your Computerland store... or other fine full 
service computer dealers. 

Ithaca Intersystems Inc., 1650 Hanshaw Road 

P.O. Box 91, Ithaca, N.Y. 14850. 

Phone (607) 257-0190 TWX: 510 255 4346. 

Z-80 is a Iradernark of Zilog. Inc 

PASCAL /Z MPU 8000 and InterSyslems are trademarks of Ithaca iniersysiems. Inc 



OODfeO 




Intersyste 

Micros for bigger ideas. 



Circle 5 on inquiry card. 



BYTE January 1981 



Editoriai. 



eliminated the "Background" and "Foreground" designa- 
tions because we have encountered many good articles 



that don't fit either category. We invite your comments, 
pro or con.B 



The November Cover 

Much mail has come in requesting further informa- . 






Hon on our November cover. It's actually a "still, " one 
of many extraordinary images from "The Works, " a 
90-minute fully computer-generated feature film. This 
science-fiction film is currently in production at the 
Computer Graphics Laboratory of the New York In- 
stitute of Technology in Old Westbury, Long Island, 
New York. The laboratory staff consists of a large 
number of exceptionally talented artists and engineers 
with extensive backgrounds in film-making, computer 
science, mathematics, and digital audio. 

The digital-animation systems are state-of-the-art, 
using many Digital Equipment Corporation computers 
that have been interfaced to frame buffers. The con- 
tents of the frame buffers are recorded onto 35 mm 
movie film with high precision. The film will be in pro- 
duction for the next two years, fudging from what I 
have seen, it should be sensational. We thank the New 
York Institute of Technology for allowing us to see 
their work in progress. We hope to report on their 
graphics activities sometime soon in BYTE. 













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BYTE's Bits 



You Can Bank On It 

Electronic home banking 
is a reality in Knoxville, 
Tennessee. The Express In- 
formation bank-at-home ser- 
vice is a joint venture of 
United American Service 
Corporation, Radio Shack, 
and CompuServe. The 
United American Bank in 
Knoxville was selected as the 
first bank to use and market 
the service to its customers. 
For a $15 to $25 per month 
fee, United American Bank 
customers can use a TRS-80 
Color Computer to access 
news and financial advisory 
services, pay bills, receive 
checking-account informa- 
tion, use a bookkeeping ser- 
vice, and to apply for loans. 
The CompuServe network 
provides the bank-at-home 
customers with a shopping 
list of national, interna- 
tional, and financial news, 
plus the latest stock quota- 
tions and commodities infor- 
mation. The United Amer- 
ican Bank plans to add its 



own bank news and daily 
information on savings and 
deposit rates. Customers of 
the bank are issued a secur- 
ity pack and certificates that 
can be redeemed at Radio 
Shack outlets. In addition to 
the financial services, cus- 
tomers can use the TRS-80 
Color Computer for home 
entertainment, education, 
security, message services, 
electronic filing, and as an 
electronic mail service. For 
details, contact Tom Sud- 
man, c/o the United 
American Bank, in Knox- 
ville, Tennesee, (615) 
971-2121; David Beckerman, 
c/o the Tandy Corporation, 
Ft Worth, Texas, (817) 
390-3273; or Richard Baker, 
c/o CompuServe, Colum- 
bus, Ohio, (614) 457-8600. ■ 



10 January 1981 © BYTE Publications Inc 



Circle 6 on Inquiry card. 



Circle 7 on inquiry card. 






If you 



^interface**** 
and you w ^J e a board for 






y Ul 



Serialtot<*K5 



axinvum 



coxnpat 
For ex 



^P le T \2rninal to get 8 ° Se-sViaring 
services, « * * ftware program d 

7S ^ovides a P°*f ^teany 
ware prov > t ne ed tow 

«'""", ..^erfacc 



inC 



iudes i 



software ^-^-^^ p^ 

orAy one aPPj^ace. 




raUelint 



Two 



.teriacetbeAPP^ 



Maybe we can 
save you a call. 



Many people have called with the 

same questions about the AIO. 

We'll answer those and a few more here. 

Oa Does the AIO have hardware handshaking? 

A: Yes. The serial port accommodates 3 types— RTS, 

CTS, and DCD/The parallel port handles ACK, ACK, 

BSY, STB, and STB. 

Cb What equipment can be used with the AIO? 

A: A partial list of devices that have actually been tested 

with the AIO includes: IDS 440 Paper Tiger, Centronics 

779, Qume Sprint 5, NEC Spinwriter, Comprint, Heathkit 

H14, IDS 125, IDS 225, Hazeltine 1500, Lear Siegler 

ADM-3, DTC 300, AJ 841. 

Q: Does the AIO work with Pascal ? 

A: Yes. The current AIO serial firmware works great 

with Pascal. If you want to run the parallel port, or both 

the serial and parallel ports with Pascal, order our 

"Pascal Patcher Disk'.' 

GL What kind of firmware option is available for 

the parallel interface? 

A: Two PROM's that the user installs on the AIO card 

in place of the Serial Firmware PROM's provide: 

Variable margins, Variable page length, Variable 

indentations, and Auto-line-feed on carriage 

return. 

GU How do I interface my new printer to my Apple 
using my AIO card? 

A: Interconnection diagrams for many popular 
printers and other devices are contained in the 
AIO Manual. If your printer is not mentioned, 

please contact SSM's Technical Support Dept. 

and they will help you with the proper 

connections. 

GU I want to use my Apple as a dumb terminal 
with a modem on a timesharing service like 
The Source. Can I do that with the AIO? 
A: Yes. A "Dumb Terminal Routine" is listed 
in the AIO Manual. It provides for full and 

half duplex, and also checks for presence 

of a carrier. 






«iyW=: d , ?*Sit°»»"f. 



to both » 






h*>£rZ*»*ZS:£Z!*f, 



going 



i compete 



alPRO^^'soHware'Usungs. 
tac\udmgj^ rROr ^tact 



cables, an ^ m q at? aUO n. 



us 



more 



gSffl 

...rw^on Drive 



2190 
San 

(408) 



Paragon 



Jose 
946 



California 
-7400 



95131 



•Apple 



TMoSAW te 
Cotnp""* 3 ' 



Qc What length cables are provided? 

A: For the serial port, a 12 inch ribbon cable 

with a DB-25 socket on the user end 

is supplied. For the parallel port, a 72 inch 

ribbon cable with an unterminated user 

end is provided. Other cables are available 

on special volume orders. 

The AIO is just one of several boards 
for the Apple that SSM will be introducing 
over the next year. We are also 
receptive to developing products to 
meet special OEM requirements. 
So please contact us if you have 
a need and there is nothing available 
to meet it. 



SSM Microcomputer Products 
2190 Paragon Drive 

San Jose, California 95131 

(408) 946-7400 



Letters 



Send + More = Code 

I certainly enjoyed Peter Frey's article 
"Machine Problem Solving, Part 2" (see 
the October 1980 BYTE, page 266), 
which concerned directed search using 
cryptarithmetic. Unfortunately the pro- 
gram does not do quite all that it is 
advertised to do, probably due to omis- 
sions in the press copy. 

For example, on page 268 Mr Frey 
stated, "It is also necessary to prepare 
the machine with the knowledge that 
blank spaces which precede letters in the 
first two rows should be treated as 
zeros." Program lines 270 and 280, 
however, can never be executed because 
of the branch instruction in line 210, 
which bypasses lines 270 and 280 com- 
pletely. As a result, problems such as 
"SPEND + MORE = MONEY" cannot be 
solved, and an error message is gen- 
erated. Changing the branch instructions 
at line 210 to cause a jump to line 270, 
instead of line 300, eliminates this prob- 



lem, as long as the short word is not 
more than one letter less than the other 
word. 

A second malfunction occurs in prob- 
lems of the "SEND + MORE = MONEY" 
type: when the sum word contains one 
more letter than the addends and also is 
a unique letter (such as in "SEND 
+ MORE = HONEY"). The program 
recognizes the patterns and alters the ar- 
ray correctly, but the value for that let- 
ter is not displayed on the screen. A 
short statement immediately after a suc- 
cessful pattern search, such as: 

415 PRINT @ 762 + 6*NL, 1 

seems to correct this error. 

K W Butcher 
Canton ME 04221 



Mr Butcher's comments are correct. 
We appreciate the feedback.... CM 



Introducing 



THE 

BcnchmarK 



WORD 

PROCESSING 

SYSTEM 



THE BENCHMARK software system sets new standards in word processing. First, it 
can be delivered to run on the CP/M or the North Star DOS, so there may be no need to 
buy a special operating system. Second, it has all the features of systems costing 
thousands of dollars more. Third, the price is as low as, or lower than, most word 
processing systems. 

Anyone can learn to run and use THE BENCHMARK in one day of self training. 
Completely self-prompting in English. THE BENCHMARK is a full capability word 
processor, has been thoroughly tested in an office environment and proved to meet the 
needs of the most sophisticated user. 

• Multi-operating system • Overtype - erases, corrects 

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THE BENCHMARK is a trademark of Metasoft Corporation 



Software for the Altos 

I read with great interest Mark 
Dahmke's article in the November 1980 
BYTE concerning the Altos machine. 
(See "The Altos ACS 8000 Single-Board 
Computer," page 158.) I agree with Mr 
Dahmke's assessment of the Altos as a 
well-designed and reliable machine. I 
was especially interested, however, in 
his comments on the available software 
for the Altos. 

I represent Avtek Inc, the software 
house that wrote APULIB and the bisyn- 
chronous and asynchronous communica- 
tions packages for the Altos machine 
mentioned in the article. The software 
picture for the Altos is not really as grim 
as the article makes it appear. Avtek has 
written many other software packages 
for the Altos. Among them: 

• OPRA— A enhancement to the CP/M 
operating system. It increases disk- 
storage capacity by 40%, disk-I/O (in- 
put/output) speed by a factor of 2, it 
supports a type-ahead buffer, and it pro- 
vides for easy mixed-mode operation. 

• Communications Packages — In addi- 
tion to the full IBM 2780/3780 bisyn- 
chronous and asynchronous packages I 
already mentioned, there is a syn- 
chronous communications package for 
Altos-to-Altos use. Incidentally, the 
price of the bisync package has been 
lowered to $495. 

• GRAFLIB—A two- and three- 
dimensional graphics-subroutine library 
for use with the Altos and a modified 
Lear-Siegler ADM-3A terminal (512 by 
256 resolution), a Diablo 1650 printer, 
and a multicolor plotter. 

• Graphics and Scientific System — A 
complete system for the Altos and the 
modified ADM-3A that contains Avtek's 
own screen-oriented editor, a scientific- 
paper typesetting package, and many 
stand-alone and subroutine packages for 
graphics and for the solution of special- 
ized scientific and mathematical prob- 
lems. This system also supports the 
Diablo 1650 printer, for graphics and 
manuscripts, etc, and multicolor plot- 
ters. 

In addition to those packages, Avtek 
has plans for several others, including a 
financial modeling package. I think that 
the software that Avtek supplies makes 
the Altos a very versatile and useful 
machine. In fact, it turns the Altos into 
a system. 

John C Theys 

President 

Advanced Computational Technology Inc 

30 Side Cut Rd 

West Redding CT 06896 



12 January 1981 © BYTE Publications Inc 



Circle 8 on Inquiry card. 



Circle 9 on inquiry card. 




Edison had over 
1,800 patents in 
his name, but 
you can be just as inventive 

with an Apple. 



Apple is the company with the brightest ideas in 
hardware and software and the best support — so you can 
be as creative with a personal computer system as Edison 
was with the incandescent bulb. 

How Apple grows with you. 

With Apple's reliable product family, the possibilities of 
creating your own system are endless. Have expansion capa- 
bilities of 4 or 8 accessory slots with your choice of system. 

Expand memory to 64K bytes or 128K bytes. Add an 
A to D conversion board. Plug into time sharing, news and 
electronic mail services. Use an IEEE 488 bus to monitor 
lab instruments. Add 4 or 6 disk drives — the 5 "A" 143K 
bytes, high-speed, low-cost drive that's the most popular 
on the market. 

Apple speaks many languages. 

Since more than 100 companies create software for 
Apple, you'll have the most extensive library in the personal 



computer world. Want to write your own programs? 
Apple is fluent in BASIC, Pascal, FORTRAN, PILOT and 
6502 assembly language. 

There's even a series of utility programs called the 
DOS Tool Kit that not only lets you design high-resolution 
graphic displays, but lets you work wonders with 
creative animation. 

More illuminating experiences in store. 

You won't want to miss all the Apple products being 
introduced at your computer store all the time. Don't let 
history pass you by. Visit your nearest 
Apple dealer or call 800-538-9696. 
In California, 800-662-9238. Or write: 
Apple Computer, 10260 Bandley Drive, 
Cupertino, CA 95014. 

tippkz computer inc. 






Circle 10 on inquiry card. 



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Telephone: (212) 279-9034 



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V 




Letters. 



68000 At Last? 



In looking over a recent issue of 
BYTE, I came across a section titled 
"BYTELINES" that contained references 
to the MC68000. (See "68000, Where 
Art Thou?" September 1980 BYTE, page 
164.) The message that I got from 
reading the commentary was that the 
MC68000 is still in the experimental 
stage. This is untrue I All unreserved op 
codes have been defined, and the in- 
struction set has been frozen since 
January 1980. The second point is that 
we have been shipping the 68000 in large 
quantities for some time now. We have 
no problem committing to delivery on 
large-production quantities. 

Since those comments were based on 
customer inputs, I can understand some 
confusion. I hope that this letter will 
help to resolve it. 

Steve Sparks 

Manager 

Marketing and Applications 

Motorola Inc 

3501 Ed Bluestein Blvd 

Austin TX 78721 

Sol Libes Replies: 

The column in question was written 
some time ago. At that time, two OEMs 
(original equipment manufacturers) that 
wanted to use the 68000 reported to me 
that they were still not able to go into 
production on planned products because 
Motorola still had not completed the 
68000's design and would not fill pro- 
duction orders. In other words, the facts 
as I reported them were true at the time. 
I understand that Motorola is now ship- 
ping production quantities. 



A System Note 



One problem with OSI (Ohio Scien- 
tific) systems (most notably the C-2) has 
been the inability to utilize the 6502 IRQ 
and NMI commands from a BASIC pro- 
gram, via USR routines. The problem 
originates from the fact that the reset 
vectors for these commands, contained 
in the system's ROM (read-only mem- 
ory), point to an area of memory that is 
heavily used by BASIC (ie: hexadecimal 
addresses 01XX). Thus, it is impossible 
to field either of these interrupts because 
BASIC rapidly destroys any service 
routine. 

My colleagues and I have proposed to 
OSI that new firmware be produced, 
identical to the old one in all respects 
but for the IRQ and NMI reset vectors. 
These would be changed to point to a 
part of memory that is "stable" (eg: 
hexadecimal addresses D0XX or E0XX). 
However, for such a new device to be 
produced, it must be financially feasible 
to do so (the cost to be in the $0.25 to 
$0.50 range). So, we would like to ask 



all interested OSI users to drop a quick 
note to Ohio Scientific expressing 
interest: 

Ohio Scientific Computers 
Attn: Customer Relations 
1333 S Chillicothe Rd 
Aurora OH 44202 

If enough replies are received, all of us 
may well see a new monitor device. 
Thanks so much! 

Shaun D Black 
University of Michigan 
Department of Biological Chemistry 
5440 Medical Sciences I 
Ann Arbor MI 48109 



Intercepting Raster 

I very much enjoyed John Beetem's ar- 
ticle entitled "Vector Graphics for Raster 
Displays." (See the October 1980 BYTE, 
page 286.) To say the least, I found it a 
unique method. However, I must take 
exception to one statement that was 
made regarding techniques for plotting 
vectors. 

In referring to the slope-intercept and 
trigonometric methods of calculation, 
Mr Beetem states, "None of these is very 
good for a small computer, because 
many slow multiplications and divisions 
are needed." This is simply not true, at 
least not in the case of the slope-inter- 
cept method. (Note: In the following 
discussion, for simplicity, it will be 
assumed that the X length is greater than 
the Y length. If this is not the case, the 
X and Y values should be swapped; the 
program under discussion handles the 
data in approximately this way.) 

The formula used in the common im- 
plementation of the slope-intercept 
method is Y=MX + B, where 
M = (Y2-Yl)/(X2-Xl) and 
B = Y2-(X2XM). In other words, the 
value that represents the slope of the line 
is multiplied by the given X value, then 
added to the origin (offset) to determine 
the Y position. To plot a vector, one 
would normally step through the X 
values and calculate matching Y coor- 
dinates from one end of the vector to 
the other. 

In examining the formula, it should be 
obvious that if X is stepped by a con- 
stant amount, then Y will also increase 
by some constant value. To reduce the 
algorithm to its simplest form, it is best 
to increment X by 1 (because, by defini- 
tion, we cannot plot any fractional 
points). One can, therefore, find the Y 
increment value simply by dividing the 
Y length by the X length. 

How complicated is the actual algo- 
rithm? Not very. Unitek Ltd is currently 
developing a high-level graphics package 



14 January 1981 © BYTE Publications Inc 



TRS-80* Model I Computer Owners . . . 




Double-density storage. 
It's really here! 



Here at Percom. And your authorized Percom dealers. 

And double-density storage is here in a big way. Because now 
you can choose from three different levels of mini-disk systems — 
all double-density rated. 

And get the storage that precisely meets your application 
needs. 

Not to mention the service and quality that's made Percom the 
industry leader. 



Although rated for double-density operation, all 
levels of Percom drives work equally well in single- 
density applications. 

You can operate these drives in ordinary single- 
density format using TRSDOS* Percom OS-80™ 
or any other single-density operating system. 

Or, you can add a Percom DOUBLER™ to your 
Tandy Expansion Interface and store data and 
programs in either single- or double-density 
format. 



Under double-density operation, you can store 
as much as 350 Kbytes of formatted data — de- 
pending on the drive model — on one side of a 
five-inch minidiskette. That's four times the 
capacity of standard 35-track Model I mini- 
disks, almost 100 Kbytes more than the capacity 
of the eight-inch IBM 3740 format! 

Available in 1-, 2- and 3-drive configurations in 
all three model lines, Percom burned-in, fully- 
tested drives start at only $399. 






TFD-40™ Drives 

TFD-40 Drives store 180 Kbytes (double-density) or 
102 Kbytes (single-density) of formatted data on one 
side of a 40-track minidiskette. Although economical- 
ly priced, TFD-40 drives receive the same full Percom 
quality control measures as TFD-100 and TFD-200 
drives. 



TFD-100™ Drives 

TFD-100 drives are "flippy" drives. You store twice 
the data per minidiskette by using both sides of the 
disk. TFD-100 drives store 180 Kbytes (double- 
density) or 102 Kbytes (single-density) per side. 
Under double-density operation, you can store a 70- 
page document on one minidiskette. 



TFD-200™ Drives 

TFD-200 drives store 350 Kbytes (double-density) or 
197 Kbytes (single-density) on one side of a minidis- 
kette. By comparison, 3740-formatted eight-inch 
disks store only 256 Kbytes. Enormous on-line stor- 
age capacity in a 5" drive, plus proven Percom 
reliability. That's what you get in a TFD-200. 




The DOUBLER™ — This proprietary 
adapter for the TRS-80* Model I com- 
puter packs approximately twice the 
data on a disk track. 

Depending on the type of drive, you 
can store up to four times as much 
data — 350 Kbytes — on one side of a 
w™"*E minidiskette as you can store using a 
Tandy standard Model I computer drive. 

Easy to install, the DOUBLER merely plugs into the disk 
controller chip socket of your Expansion Interface. No rewir- 
ing. No trace cutting. 

And because the DOUBLER reads, writes and formats 
either single- or double-density disks, you can continue to 
run all of your single-density software, then switch to dou- 
ble-density operation at any convenient time. 

Included with the PC card adapter is a TRSDOS*- 
compatible double-density disk operating system, called 
DBLDOS™, plus a CONVERT utility that converts files and 
programs from single- to double-density or double- to sing- 
le-density format. 

Each DOUBLER also includes an on-card high- 
performance data separator circuit which ensures reliable 
disk read operation. 

The DOUBLER works with standard 35-, 40-, 77- and 
80-track drives rated for double-density operation. 

Note. Opening the Expansion Interface to install the 
DOUBLER may void Tandy's limited 90-day warranty. 

Free software patch This software patch, called PATCH PAK™, 
upgrades TRSDOS* for operation with improved 40- and 77- 
track drives. For single-density operation only. 



Quality Percom products are available at authorized dealers. Call toll free 
1-800-527-1592 for the address of your nearest dealer or to order directly from 
Percom. In Canada call 519-824-7041. 



trademark of Percom Data Company, Inc. 



Prices and specifications subject 10 change without notice. 




trademark of Tandy Radio Shack Corporation which has no relationship to Percom Data Company Circle 1 1 OD inquiry Card. 



PERCOM DATA COMPANY. INC. 

311 N KIRBY ■ GARLAND TX ■ 75042 
(214J 372-3421 



Circle 12 on inquiry card. 



MORE FOR YOUR 

RADIO SHACK 
TRS-80 MODEL I ! 



* MORE SPEED 

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Compiled code plus VIRTUAL 
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* MORE INSTRUCTIONS 

Add YOUR commands to its large in- 
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Far more complete than most Forths: 
single & double precision, arrays, 
string-handling, more. 

* MORE EASE 

Excellent full-screen Editor, structured 
& modular programming 
Optimized for your TRS-80 with 
keyboard repeats, upper/lower case 
display driver, single- & double-width 
graphics, etc. 

+ MORE POWER 

Forth operating system 

Interpreter AND compiler 

Internal 8080 Assembler 

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disk and tape 

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FORTH 



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PROFESSIONAL SUPPORT 

Source code provided 
MMSFORTH Newsletter 
Many demo programs aboard 
MMSFORTH User Groups 
Programming staff can provide advise, 
modifications and custom 
programs, to fit YOUR needs. 

MMSFORTH UTILITIES DISKETTE: Includes 
FLOATING POINT MATH (L.2 BASIC ROM 
routines plus Complex numbers, 
Rectangular-Polar coordinate conversions, 
Degrees mode, more), plus a full Forth-style 
Z80 ASSEMBLER; plus a powerful CROSS- 
REFERENCER to list Forth words by block 
and line. All on one diskette (requires 
MMSFORTH, 1 drive & 16K RAM), . . $39.95* 

THE DATAHANDLER V1.1, a very soph- 
isticated database management system 
operable by non-programmers (requires Disk 
MMSFORTH, 1 drive & 32K RAM); with 
manuals $59.95* 

FORTH BOOKS AVAILABLE 

MICROFORTH PRIMER (comes with 

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USING FORTH — more detailed and advanc- 
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■ >atteri 

for a commercial graphics product, and 
the vector routine uses this method. The 
division itself encompasses only fifteen 
instructions (30 bytes), and need be done 
only once, which is before the actual 
write loop is entered. The loop proper 
contains only an X increment instruc- 
tion, a double-precision add (two in- 
structions) for the Y increment, the ac- 
tual write-routine call, and a simple test 
for end-of-vector. Since Mr Beetem is 
using an 8080 and Unitek's system is 
6800-based, a speed comparison would 
be worthless. Suffice to say that the 
routine actually calculates the vector 
faster than the hardware can plot the 
points. 

To show the simplicity of the 
algorithm, here is a minimal representa- 
tion: 

1. Find the lengths of the X and Y com- 
ponents of the vector. 

2. Divide the Y length by the X length. 

3. Set location to X, Y origin. 

4. Set the X increment to 1. 

5. Set the Y increment to the result of 
the division. 

6 . Set the Y fraction register to hexa- 
decimal 80 {Vi for round-up). 

7. Plot the location. 

8. If location is end-of-vector, stop. 

9. Increment X. 

10. Add the Y increment to the Y frac- 
tion register. 

11. If an overflow occurs, increment Y. 

12. Go to 7. 

As can be seen, the algorithm is rather 
simple, and uses no complex mathe- 
matics in the loop. 

It turns out that this method solves a 



particularly knotty problem that crops 
up in other variations (especially in a 
parametric line representation). When 
vectors approach angles that are multi- 
ples of 45° (ie: the X length nears the Y 
length), varying overflow rates in the 
two variables cause undesired excursions 
away from the actual vector. This 
creates a rough section about the points 
where steps would normally occur. In- 
crementing one of the variables by 1 
eliminates any possibility of variable 
overflow and results in a very smooth 
vector. 

I found Mr Beetem's logic interesting 
and informative; had I considered this 
method of drawing vectors when we at 
Unitek were designing our graphics 
package, I probably would have discard- 
ed it without careful examination, 
believing it too slow and complex. Mr 
Beetem has proven this not to be so. 
Perhaps the same thing happened when 
Mr Beetem was writing his routine. He 
too may have considered the slope-inter- 
cept method briefly, but discarded it, 
without closer examination, as being too 
clumsy. (Alas, it always seems that the 
algorithm one discards later turns out to 
be the variation with the greatest poten- 
tial....) In this case, it happened for the 
best; otherwise, we would not have Mr 
Beetem's method to consider. I do not in 
any way intend to detract from his ap- 
proach; merely to indicate that the 
slope-intercept is also a viable method 
for microcomputers. 



CET 



Richard H Rae 
Unitek Ltd 
POB 671 
Emporia VA 23847 



Fewer Resistors = 
Same Resistance 



In the August 1980 BYTE, W Lloyd 
Milligan shows a network of twenty-six 
1-ohm resistors (see "Letters," page 20) 
that he believes is the smallest net- 
work whose value is very close to w (pi). 
However, by using the same continued- 
fraction principle with only six parallel- 
connected resistors, a solution with a 
total of only eighteen resistors is shown 
in figure 1. Alas, I have been unable to 



find any network that starts with three 
in series with fewer resistors; starting 
with two in series, there is another solu- 
tion with eighteen. All of these differ 
from t by about one part in four 
million. They all have the value 
355/113. 

Can anyone find a solution with 
seventeen or fewer? 

John Fitzallen Moore 
714 E Birch Rd 
Lake Bluff IL 60044 



Figure 1 



-JVW-'WWvVv- 



WWVVAVvl 



fWWWv-«AVi I 



fVWAW-^/^A'<l 



— vw-vwl 



16 January 1981 © BYTE Publications Inc 



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An Introduction 
to Atari Graphics 



Chris Crawford and Lane Winner 

Atari Inc 

1272 Borregas Ave 

Sunnyvale CA 94086 



The Atari 400 and 800 are second-generation personal 
computers. In addition to the normal memory and pro- 
cessor integrated circuits, they contain three special- 
purpose LSI (large-scale integrated) circuits which make 
them capable of many feats of computing legerdemain. 
Most of this power, however, lies brooding beneath 
many layers of "human engineering." The beginning pro- 
grammer working in BASIC is paternalistically protected 
from the complexities and power of the beast within. The 
more experienced programmer seeking cybernetic high 
adventure must first defeat the friendliness engineered in- 
to the machine to unleash its throbbing brute power. 
Without help, this can be most difficult. We will act as 
native guides for one region of this complex machine: the 
display list. We will show you how to generate flashy dis- 
plays by creating you own display list and redefining the 
character set. 

Display-List Fundamentals 

Most personal computers use a straightforward mem- 
ory-mapped display in which the screen format is fixed 
and each screen pixel's (picture element's) contents are 
provided by a specific location in memory. This is a sim- 
ple scheme demanding little of either the programmer or 
the computer. The Atari 400/800 uses a more complex 
scheme involving a display list and display data. A dis- 
play list is a sequence of commands that defines the ver- 
tical format of the video display; the display data is the 
information to be displayed. 

The Atari 400/800 display list is actually a small pro- 



gram; it is processed by a special LSI circuit called 
ANTIC. ANTIC is a dedicated microprocessor whose 
sole function is to control the video display. ANTIC uses 
a process called DMA (direct memory access) to gain ac- 
cess to the display list and display data. The display list 
and display data are stored by the high-speed (1.8 MHz) 
6502 microprocessor. When the BASIC programmer 
types GRAPHICS n, the operating system writes a com- 
plete display list into memory and clears the display data. 
The information flow for this process is diagrammed in 
figure 1. Clearly, the adventurous programmer who by- 
passes BASIC and writes his or her own display list will 
have more direct control over the screen. 

Associated with the display list are the concepts of a 
graphics mode and a graphics-mode line. The Atari 
400/800 supports fourteen fundamental graphics modes, 
only nine of which are directly accessible from BASIC. 
The first six modes (three of which are accessible from 
BASIC) are character modes which display characters in 
different combinations of size and color. The remaining 
eight graphics modes display squares of color in different 
resolution and color combinations. A graphics-mode line 
is a group of horizontal-scan lines which are treated as a 
unit for display purposes. (A horizontal-scan line is a 
single sweep of the electron beam across the television 
screen. There are 192 horizontal-scan lines in the visible 
area of the screen.) A graphics-mode line will contain be- 
tween one and sixteen horizontal-scan lines, depending 
on the graphics mode involved. A graphics-mode line 
stretches horizontally all the way across the screen (you 




BASIC 



OPERATING 
SYSTEM 




6502 
MICRO- 
PROCESSOR 



DISPLAY LIST 

AND 

DISPLAY DATA 



ANTIC 

AND 

CTIA 

LSI 

CIRCUITS 



TELEVISION 
SCREEN 



Figure 1: Information flow for Atari 400/800 display. The adventurous programmer who bypasses BASIC gains more control over 
the display list and display data, and thus is able to customize the displayed image to a greater extent. 



18 January 1981 © BYTE Publications Inc 



Circle 15 on inquiry card. 




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MusicSystem 

All the Instruments 
Anyone with an Apple 




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Digital Synthesizer with 16 Voices. Stereo output. 
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Drop by your Apple, Dealer and ask to hear for\ 
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Music I can play? Send details. 



'Apple is a trademark ol Apple Computer, Inc. 



cannot change graphics modes halfway across the 
screen). The video display is thus organized as a vertical 
sequence of mode lines of varying height and contents. 
There are many thousands of possible sequences of mode 
lines on the screen; BASIC restricts the programmer to 
seventeen such sequences. Each such sequence is referred 
to in the BASIC manual as a graphics mode. 

Display-List Details 

The display list and the display data normally reside at 
the top of available memory-address space. Since the 
amount of available memory is not fixed, the operating 
system must keep track of the address of the display list. 
The address of the beginning of the list is stored in 
decimal addresses 560 and 561. The first 3 bytes in the 
display list skip twenty-four blank scan lines, which is 
necessary to defeat the vertical overscan of many televi- 
sion sets. The next byte is called the LMS (load memory 
scan) byte. It defines the first mode line of the display and 
also instructs ANTIC that the following 2 bytes give the 
address at which display data can be found. Since we 
rarely need to tamper with these first 4 bytes, we will 
start with the fifth byte, whose address we will assign to a 
BASIC variable called START. The value of START can 
be calculated by: 

START = PEEK(560) + 256*PEEK(561) + 4 

The bytes at this location and the succeeding location 
give the starting address of the display data. Beginning at 
location START +2 is a sequence of mode bytes which 
specify the mode lines for the display. The codes for these 
mode bytes are found in table 1. The programmer has the 
freedom to create any sequence of mode bytes for the 
display list. The programmer also has the responsibility 
to insure that the chosen sequence includes exactly 192 
horizontal-scan lines. At the end of the mode-byte se- 
quence, the programmer must place an ANTIC JUMP 
byte (decimal 65) followed by the low- and high-order 
address bytes of the beginning of the display list — four 
bytes lower in memory than the location we refer to as 
START. 

The starting address of the display data, which we will 
assign to a BASIC variable called MEMST, can be cal- 
culated from: 

MEMST = PEEK(START) + 256 *PEEK(START + 1) 

The display data is simply strung together in sequence; 
this can cause a headache when mixing modes. Since dif- 
ferent mode lines require different numbers of display- 
data bytes, the programmer wishing to change a display- 
data byte must calculate its position in display-data 
memory by adding up the space requirements of each 
previous mode line. The BASIC POSITION and PLOT 
commands work reliably only with the homogeneous 
display lists used by BASIC, so the programmer who 
mixes modes must expend greater effort to use such a 
specialized display. 

A Real Display List 

We shall now illustrate these principles with a sample 
program and its resultant display, display list, and dis- 
play data. The program is a straightforward affair which 
plots the BYTE logo in graphics mode 7+16. The pro- 



20 January 1981 © BYTE Publications Inc 



Circle 16 on inquiry card. 



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removing the Apple n ROMs. Available with 
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7S10A Solder Board. 

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California Computer Systems 

250 Caribbean Sunnyvale, CA 94086 (408)734-5811 















Scan 



















Color 


Lines 


















Dots 


Per 


Number 




Bytes 






Left 


Right 




Per 


Mode 


of 


BASIC 


Per 


Mode 


Remark 


4 Bits 


4 Bits 




Pixel 


Line 


Colors 


Mode 


Line 


character 







2 




Vt 


8 


V/2 





40 


character 







3 




Vz 


10 


VA 


— 


40 


character 







4 




1 


8 


4 


- 


40 


character 







5 




1 


16 


4 


— 


40 


character 







6 




1 


8 


5 


1 


20 


character 







7 




1 


16 


5 


2 


20 


character 







8 




4 


8 


4 


3 


10 


character 







9 




2 


4 


2 


4 


AO 


graphic 







A 




2 


4 


4 


5 


20 


graphic 







B 




1 


2 


2 


6 


20 


graphic 







C 




1 


1 


2 


— 


20 


graphic 







D 




1 


2 


4 


7 


40 


graphic 







E 




1 


1 


4 


— 


40 


graphic 







F 




«/s 


1 


VA 


8 


40 


special 


2 


0-7 







Blank 


— 


— 


— 


— 


special 


3 


4 


1 




JUMP 


— 


— 


— 


— 


Table 1: Interpretation of the graphics 


-mode-byte 


codes 


. Remarks are 1 


is follows: 








1. 


The left nybble 


of the very 


first mode byte of the display list must be ch 


anged from to 4. 






2. 


The blank mode is used to 


output a si 


lected 


number of blank background lines. 






3. 


The JUMP instruction causes the ANTIC graphics processor 


to recognize 


the end of the display list and 


return to 




the beginning of the list, w 


aiting for vertical blanking to occur so it can 


proceed with anoth 


er frame. 




Where IV2 colors 


are indicated, the hue 


of the 


foreground color cannot be controlled. 








Photo 1: The BYTE logo as displayed by the Atari 400/800 run- 
ning the program of listing 1. See table 2 for details. 



gram is presented in listing 1 (page 24), and the display it 
produces is shown in photo 1. Figure 2a and table 2a 
show the display list for this display. Since this is a stan- 
dard BASIC graphics-mode display list, it is neat and 
tidy. 

Tampering With the Display List 

With the formal goal of improving the display and the 
heuristic goal of demonstrating display-list manipula- 
tions from BASIC, we shall now tamper with this display 
list. The first step in this process is to prepare our pro- 
posed display list on paper. The desired screen format is 
shown in figure 2b. 



We must consult table 3 to determine which of the 
display modes will require the greatest amount of 
memory space. In our case, we are using modes 0, 1, 2, 
and 7; mode 7 is clearly the most memory-intensive 
mode. We shall therefore start with mode 7 and modify 
the mode-7 display list. It is always easier to pare down 
an oversized display list than to build up an undersized 
one. 

Next, we must verify that our proposed display list 
does indeed produce 192 horizontal-scan lines. Consult 
table 1 to find the number of scan lines per mode line. 
Our calculation produces the following results: 



ode 


Number 


Scan Lines 


Total Scan 




of Mode 


Per Mode 


Lines 




Lines 


Line 







1 


8 


8 


1 


4 


8 


32 


2 


4 


16 


64 


7 


44 


2 


88 



192 Total 

We now determine the mode bytes for each of the 
mode lines by looking them up in table 1. It is handy to 
convert these to decimal for later use. Our results are: 



ode 


Hexadecimal 


Decimal 




Mode Byte 


Mode Byte 





02 


2 


1 


06 


6 


2 


07 


7 


7 


0D 


13 



22 January 1981 © BYTE Publications Inc 



Circle 17 on inquiry card. 



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ON S-100 BUS 
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(714) 296-91B2 



Listing 1: Atari 400/800 program to plot the BYTE logo, shown in photo 1. See table 2 on page 26 for details. 



100 
HO 
120 
130 
SCO 
BiO 
820 
830 
90 C 
905 
910 
915 
920 
925 
930 
935 
940 
945 
950 
955 
960 
965 
970 
975 
980 
9S5 
99 



GRAPHICS 7JC0L0 

A*0!READ B*CSIF 

READ A»B»C:iF A 

END 

ON A+l GOTO 310 

plot b»c:return 
drawto b»c:retu 
position b»c:xi 

DATA lllf30s.Hl 
106*35*106 
111*41*110 
106*46*107 



R ItPOKE 765,1 J POKE 710*123 
B>-1 THEN GGSUB 80QJGOTG 1 
1 THEN GOSUB SOOtGOTC 120 



J POKE 
10 



712*128 



820*830 



RN 



DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 



1*-1*1 
?-97*30 
88 * 35 
79*35 
77*32 
71*46 
67*44 
58*46 
,j\j * cib 
51*39 
49*30 
49*51 
46,32 
45*33 
36 * 30 



97 
0* 

■f 

X * 

0* 
2* 
1, 
1* 
1* 



? <3 

,4 
*4 
*5 
93 
88 
79 
76 
70 
67 
54 
54 
51 
49 
48 
46 
45 
49 



13**6*0*0 
1,110,31, 
6*107*37? 
1*109*41 
7f 107*48 
96*5 
1*92 
1*87 
2*78 
1*74 
1*70 
1*66 
2*54 
0*54 
li 51 




: RETURN 



*31 
*50 
*35 
*31 
*30 
*50 
*46 
*31 
f42 
»32 
*51 
*33 
*33 
*30 



*49 
»48 
*46 
f47 



,"S 

109 

107*33*108 

103*42*107 

108*49*109 

*1*96*50»2 



31* 
51* 
34* 
31* 
46* 
51* 
44* 
31* 
50* 
33* 

wllj * 



43*0 
51*1 
-1*0*0 



91*31 

80*51 

78*34 

74*30 

69 

59 

64 

54 

50 

49 

48*42 

46*49 

36*51 



*43 
*51 
*43 
*43 
*51 
*43 



3ii» 

39, 
43* 
50, 



10 
10 
10 
11 



7*33*107*34 
9,40*110*40*111*40 
7*44*106*45 
0*50*111*50*111*51 



96*31 
90* 
79* 
78* 
93* 
69* 
58 * 
63 , 
51* 
50* 
49* 
48* 
45* 



32*1*89*33*1*89*34 

50,0*79*50 

33 * * 78 * 33 * 2 , 77 , 32 

71*30 

63*44*1*68*46 

58*50 

63*31*1*62,30 



30 *0* 

46,1* 

50,0* 

42 , 1 , 

31 

42,0* 

49 

39 f Of 

48fl, 

oG , , 



50,39,1,50,30 

48f31, 1,48*30 
45 ,43 
35*50*2,35*31 



a) 



NORMAL 



96X2 = 192 



TOTAL=192 



MODE 7 
96 LINES 



b) 



192 

SCAN 
LINES 



MODIFIED 



MODE 7 9 LINES 



MODE O 1 LINE 



MODE 7 35 LINES 



MODE 1 4 LINES 



MODE 2 4 LINES 



9X2 = 


18 


1X8 = 


8 


35 X 2 


= 70 


4X8 = 


32 


4 X16 


= 64 



TOTAL=192 



Figure 2: Horizontal-scan line arrangement for normal- and modified-display screens. The video screen in figure 2a is composed com- 
pletely of mode-7 horizontal lines. In figure 2b, the video screen is constructed from multiple-mode sections that allow a mix of im- 
ages to be displayed. Refer to table 2 for details. 



The results of this paperwork are presented in table 2b. 
Now, at last, we are ready to write some code. Please 
refer to listing 2 on pages 28 and 30 in conjunction with 
this narrative. We begin by checking to see that there is 
enough memory available to reposition the display list 
(line 0). If there isn't enough, the program aborts. We 
then move the top of available memory down by 4 K 
bytes and execute a GRAPHICS call (line 20) to write a 



new display list and display data in memory. This pro- 
cedure reserves 4 K bytes of memory for our own use 
later on. We then define our display strings (lines 30 and 
40) and execute another GRAPHICS call to initialize our 
display list — which we shall subsequently modify. The 
series of POKEs in lines 50 and 55 define the colors we 
will be using and turn off the character display while we 
redefine our characters. 



24 January 1981 © BYTE Publications Inc 



Circle 1B on inquiry card. 



GRAPHIC 



T F R KA I N A I P0CKETABLE d|g|t|zer 




GRAPHIC SOFT BOX-I (12K LEVEL) 



( """" ) (""" "°") ( "■'" ) ( "«"' ) ( cSStlOL ) ( """ ) ( CO°M»?»0 ) 



E 




6 



* 



- t, BMW 00r UH i T II IMPUTING X-Y AXIS Bi *[v 



\ 


T 


/ 


<— 




-» 


/ 


1. 


\ 



&.PATTERN ANALYSIS 

FANTA STICK-I is a multifunctional 
terminal that lets you draw and move 
patterns on the screen, and is also 
capable of analyzing drawn patterns. 
FANTA STICK-I is designed to im- 
prove functional performance using 
integrated circuits and highly ma- 
nipulative telephone keys. 
It is plug compatible with APPLE- 
II and especially designed for such 
fields as production of commercial 
animation, promotional demonstra- 
tion, graphic analysis, and develop- 
ment of software. 



■ HARDWARE 

FANTA STICK-I consists of stick, 
SW1-3 switch, tenkey, I/O expansio. 
connector, pilot lamp, and change 
over switch on the reverse side. Stick 
and CHI -3 switch are used for mak- 
ing patterns and playing games. 
Tenkey is used for inputing dot to 
the screen, graphic mode command, 
box-position command, and save 
and load patterns. I/O expansion 
connector is useful with I/O connec- 
tor inside APPLE by only changing 
switch for using expansion connec- 
tor without removing FANTA 
STICK-I. 

If you need higher performance, you 
just add another FANTA STICK-] to 
I/O connector. 



■ SOFTWARE 

A feature of this software is the 
division of the screen into twenty 
individual boxes, for drawing pat- 
terns, and memory. Then the boxes 
are reassembled to make a whole 
screen. 

It does not only draw patterns by 
putting together the boxes and pat- 
terns made with slide and revolve 
command, but composes new 
screens by putting together the man- 
aged pattern. 

Box system has the advantage of a 
close management. 
There are many features, such as 
making patterns with expanding box 
by three times on the screen, com- 
puting the area of dots in a desig- 
nated window. 

Using a disk, you can freely operate 
a graphic pattern with save and load 
command. 



an 

;e- 










T.I. P. INC 2-1-19 Kanda-Surugadai, Chiyoda-ku, Tokyo Japan 
Phone: 03-295-7055 Telex: 02226152 TIPINC I 

(Exclusive Agent) HYPERSOFT INTERNATIONAL, INC. 

3928 S. Sepulveda Blvd #9, Culver City, CA 90230 
Phone: (213) 397-2274 



DEALER INQUIRIES INVITED 











Modified 








Mode-7 






Mode-7 








Display 






Display 






Mode 


List 


Scan 


Mode 


List 


Scan 




Line 


Hexadecimal/ Decimal Line 


Line 


Hexadecimal /Decimal 


Line 




Number 




Number 


Number 




Number 


LMS Byte 


1 


(4D) 77 2 


LMS Byte r 1 


(4D) 77 


2 


Start 


_ 


lo 


— 


Start 


— 


lo 


— 




_ 


hi 


— 




— 


hi 


— 




2 


(OD) 13 4 




2 


(OD) 13 


4 




3 


(OD 13 6 


Mode 7 


3 


OD 13 


6 




4 


(OD) i 


9 lines ' 


4 


(OD) 13 


8 


















5 


(OD) 13 


10 


















6 


(OD) 13 


12 


















7 


(OD 13 


14 


















I 8 


(OD) 13 


16 
















Mode 0~\ ? n 

1 linp / - lu 


(OD) 13 
(02) 2 


18 
26 


Mode 7 














i imc j 


r 11 


(OD) 13 


28 


96 lines 














Mode 7 


12 
1 


(OD) 13 


30 
1 
















35 lines < 


\ 


{ 


















44 


(OD 


I 13 


94 


















[ 45 


(OD 


) 13 


96 
















r 46 


(06 


6 


104 
















Mode 1 J 47 


06 


6 


112 
















4 lines \ 48 


(06 


6 


120 




' 


' 


' 


' 


' ^ 


' 


<- 49 


06 


6 


128 














r 50 


07 


7 


144 




94 


(OD) 13 188 


Mode 2 J 51 


07* 


7 


160 




95 


OD 13 190 


4 lines \ 52 


07 


7 


176 




96 


OD) 13 192 


^- 53 


07 


7 


192 




JUMP 


(41) 65 


JUMP 


(41 


65 








lo 






lo 








hi 






hi 








(a) 






(b) 




Table 2: Normal- and modified-display lists 


correspond to the lines displayed in figure 2. The program corresponding to table 


2a is given 


in listing 1, 


and the actual displa 


y is pictured in photo 1. Listing 2 corresponds to table 2b. 





Mode 8 + 


16 


8138 Bytes 


8 




8112 


7 + 


16 


4200 


7 




4190 


6 + 


16 


2184 


6 




2174 


5 + 


16 


1176 


5 




1174 


4 + 


16 


696 


4 




694 


3 + 


16 


432 


3 




434 


2 + 


16 


420 


2 




424 


1 + 


16 


672 


1 




674 







992 


Table 3: Memory requirements for various graphics modes. 



We then calculate the variable START in line 60. In 
lines 70 thru 90, we POKE the new and different mode 
bytes into the display list to create our new display list. 
The offsets from START (the numbers added to START) 
are simply the mode-line numbers for the new mode 
lines. Thus, the offset in line 70 is 10 because the mode 
byte we are POKEing is for the tenth mode line from the 
top of the screen. (Remember, a mode line is not the same 
as a scan line.) In line 95, we POKE the ANTIC JUMP 
byte and the jump-address bytes at the end of our new 



display list. The value of the jump-address bytes points to 
the beginning of the display list and can be found in loca- 
tions 560 and 561. 

We have just created a new display list on top of the 
original one. Now we must put a display onto the screen. 
This will be a tricky operation; as we mentioned earlier, 
the PLOT and POSITION commands will not quite work 
as we expect them to. Some extra effort is necessary to 
produce a display. Fortunately, our GRAPHICS 7 plot- 
ting of the BYTE logo will still work the same way. 
Because we have inserted a mode-0 line above it, the logo 
will be shifted down on the screen by six scan lines. This 
shift is so small that we can neglect it and plot the logo 
with the same routine used earlier. This is done in lines 
110 and 120. 

Now that we have plotted the logo, we desire to print 
some other characters as shown in photo 2 on page 32. 
Two problems impede us: first, we must redefine the 
character set to mix uppercase and lowercase characters; 
second, we must calculate where these characters go. 

The first problem arises from the natural limitations of 
an 8-bit processor. If four colors are supported (as in 
GRAPHICS 1 and 2), only 64 distinct characters can be 
displayed in each color. This is because 2 bits are required 
to specify the color, leaving only 6 bits to specify the 
character. This restricts our available set; the Atari char- 
acter set in ROM (read-only memory) supplies uppercase 
and punctuation or lowercase and graphics symbols, but 

Text continued on page 32 



26 January 1981 © BYTE Publications Inc 




There are Daisies!. . . And, There are Daisies!. . . But Vista has a Peach! 

The Vista V300 is exactly that, a "peach" of a daisy wheel printer both from the standpoint of price 
and performance. 

Think of it, a printer at nearly half the price (when compared to models even remotely competitive in 
quality) combined with the ultimate in reliability, print quality, and flexibility. 

Typical Comments: "Superb print quality!", "Highly reliable.", "Definitely letter quality. . . I can't 
believe the price tag.", "Best use I've seen yet of LSI Technology." 

But judge for yourself — look at the V300 features and keep in mind this is a letter quality printer at 
dot matrix prices. 

• Tractor option available 

• Print Speed — 25 CPS (Optional 45 CPS for $2,195) 

• Print Wheel — Industry standard 96-character Daisy Wheel 
(including the extended-life dual plastic wheels) 

• Service — Prompt maintenance/service agreements avail- 
able nationwide 

• Interface — Industry standard parallel (RS232-C optional) 

• Printable Columns — 136 

• Warranty — 90 days parts and labor, one year parts only 

• Proportional, bi-directional printing • Programmable VFU 

• Extensive self-test functions • Hardware and software 
compatible 

Vista does it again! Quality, Price and Perfor- 
mance with a peach of a daisy wheel printer. 



Wffff 



AND, Vista Has a Complete V100 Word Pro- 
cessing System for Only $4995! 


The Vista V100 is a complete word process- 
ing system that includes: 


• Exidy Sorcerer 
Computer, 48K 

• V200E20 Disc Drive 
System, Double 
Density 

• Sanyo Data Display 
Monitor 


• Vista V300 Printer 
Full Character Daisy 
Wheel 

• Wordstar, CPM™ 1.4 
(Includes E Basic) 

• Can also be used for 
Data Processing 



IMMEDIATE DELIVERY 

For Further Information 
Call Toll Free (800) 854-8017 

The Vista Computer Company 1401 Borchard Street • Santa Ana, California 92705*714/953-0523 



CPM is a trademark of Digital Research 



Circle 19 on inquiry card. 



BYTE January 1981 27 



Listing 2: Atari 400/800 program to plot the BYTE logo and the other characters as displayed in photo 2. 





2C 

30 

40 

50 

55 

60 

70 

80 

90 

95 

11 

12 

20 

21 

22 

23 

24 

25 

29 

30 

31 

32 

33 

3* 



IF FRE( 0X5325 THEN PRINT "NOT ENCUG 
RAMTOP=PEEK < 1 06 > J POKE 1 06 t RAMTGP-16 
DIM SML$(32):3ML*(l»32> = Ii the smal 
DIM MGHifc ( 41 ) t MGH* < 1 1 41 ) = a @(23A©McGRA 
GRAPHICS 7+16t COLOR 2 J POKE 765 1 2 
POKE 708»128JPOKE 709»40tPQKE 710 »1 
START=PEEK ( 560 ) +PEEK ( 56 1 ) *256+4 
POKE START+10»2 
FOR X=0 TO 3 t POKE 
FOR X=0 TO 3: POKE 
POKE START+54»65: 

o a=o:read b»c:if 



n MEMORY! "J END 

: GRAPHICS 

1 systems Joi.irn3l 

WeHILLB@e@eS@SPUBLICATION' 

:s:poke 712,123 



START+46+X»6:NEXT 

START+50+X»7tNEXT 

:POKE START+55»FEEK 

B>-1 THEN G0SU3 80 



READ A»B»C:iF A>-1 THEN GOSUB 80 0J 

CHBAS=RAMTQP-4 : ADDR=CHBAS*256 

FOR X=0 TO 1023: POKE ADDR+X»PEEK (5 

POKE 756>CHBAS+2 

FOR X=0 TO 255: POKE ADDR+512+X rPEE 

FOR X=0 TO 7: POKE ADDR+5i2+X»0 JNEX 

FOR X=0 TO 7: READ A: POKE ADDR+99*S 

POKE 755 r0 {POKE 87 , 

G POSITION 4,9:? #6? "AUGUST 1980 Vo 

MEM3T==PEEK ( START ) +PEEK ( START+1 ) *25 

C FOR X=l TO LEN<8ML$)JPGKE CHRP03+X 

CHRPGS=CHRFQS+6 

C FOR X-l TO LEN( MGH* ).l POKE CHRPOS+X 



X 
X 
(560) IPOKE START+56r PEEK (561) 

o:goto 110 

GOTO 120 



7344+XKNEXT X 

K(ADDR+256+X):NEXT X 
T X 

+x»a:next x 

luirie 5, Number 8° * 
6 : CHRP0S-MEMST+46*4 
-1»ASC<SML*(X»X))+128:NEXT X 

•l»ASC(MGH$(XfX))-64:NEXT X 

Listing 2 continued on page 30 



A MAJOR NEW YORK BANK 
INVITES YOU TO BANK AT HOME 

. . . By Personal Computer 

Our system talks with Yours. A program diskette provides 

access to the bank for! 

bill paying 

account transfers 

balance inquiry 

record keeping 
Software requires 48K bytes of memory and one disk drive. 
This is a pilot program. For more information. Please terminate 
this message by sending in the form below. 



NAME 

ADDRESS. 



TELEPHONE NO 

Name and type of system 

Do you have communications capability?-. 
If not. are you planning for it? 

MAIL FORM TO! Home Banking System 
P.O. Box 721 
Radio City Station 
--~_ New York, New York 10101 



.CITY STATE. 



.ZIP. 



28 January 1981 © BYTE Publications Inc 



Circle 20 on Inquiry card. 



THE DAWN OF 
A NEW AGE 




The 2nd Generation is here! 



MEASUREMENT systems & controls proudly 
introduces its new and exciting "2nd Generation" 
family of S-100* compatible products. Each has 
been specifically designed for use with 
multi-user and network 
operating systems such 
as MP/M, CP/NET, and 
OASIS. Every product is 
fully tested and burned- 
in, comes with a 1 year 
guarantee, and offers 
you features not 
currently available from 
any other source. 

Z80 PROCESSOR 
BOARD — The most 
powerful CPU board available today. Outstanding 
features include 4MHz operation, high-speed serial 
and parallel I/O utilizing DMA or programmed 
control, eight vectored priority interrupts, and a 
real time clock. 

MULTI-USER SERIAL I/O BOARD — For use in 

expanded systems requiring up to eight additional 
serial I/O ports. Features include: 16 maskable 

'AH products meet the new IEEE standards. 




Systems 




a Division of MEASUREMENT systems 8. controls 

incorporated 



vectored priority interrupts, RS-232C interfaces 

with full handshake, asynchronous or synchronous 

operation with asynchronous baud rates to 19,200. 

Available in four or eight channel versions. 



DOUBLE DENSITY 

FLOPPY DISK 

CONTROLLER BOARD- 

controls up to four Sc- 
inch or 8-inch disk drives 
using IBM soft sectored 
formats. It features 1K 
of on-board buffering, 
DMA controlled data 
transfers and the per- 
formance character- 
istics of the superior 
NEC 765 chip. 



64K BANK SELECTABLE MEMORY BOARD — 

Features include I/O port addressing for bank 

select with 256 switch selectable I/O ports for the 

memory bank addressing. The memory is 

configured as four totally independent 16K 

software-selectable banks, with each bank 

addressable on any 16K boundary. 

"Attractive Dealer & OEM Prices" 
~ See your nearest computer dealer, or 

contact us for the complete story on 
The 2nd Generation. 



867 North Main St. / Orange, Calif. 92668 
(714) 633-4460 TWX / TELEX: 678 401 TAB IRIN 



Listing 

35G 
360 
BCD 
610 
B2 
83 
900 
9G5 
910 
915 
92 
925 
930 
935 
940 
945 

95 
955 

96 
965 
970 
975 

98 
9£5 

99 
999 



2 continued: 

POKE 7 
GOTO 3 
OK A+l 
PLOT B 
DRAWTO 
POSITI 



DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 
DATA 



03*200 
60 

GOTO 8 
rCJRETl 

B?CiRE 
ON B»CJ 

11 jr 20 f 1 

Q6»25>1 

11*31*1 
06*36* 1 



10*820*8 
RN 
TURN 
XIO 18 t* 

1 1 > 2 1 * 1 1 



30 



6 

*1Q7 
9 



j. 
2 


1 

1 
2 

1 
1 
1 
1 
1 

DATA 
DATA 1 
DATA 



97 
83 
79 
77 
71 
67 
53 
55 
51 
49 
49 
46 
45 
36 
60 



:o 



36 

3* 

36 

2G 

29 

20 » 

41» 

22 * 

2S* 

20* 

96* 



10? 31*10 
07*37*10 

97*41 * 2* 
0*93*21* 
1*38*40* 
0*79*25* 
2*76*21* 
1*70*20* 
1*67*40? 
1*54*36* 
2*54*21* 
0*51*32* 
1 * 49 * 22 * 
1*48*41* 



»46*^u* 



41 

1*45*23* 
1*49*20* 
96*96*60 



/ 

96 

1 

1 

1 
1 
1 

2 


•i 

X 



•I 

1 






o * o * " s ; 



i-.lt 

27* 
31* 
38* 
,40 
92* 
87* 
78* 
74* 
70* 
66* 
54* 
54* 

ZlX * 

49* 
4S* 
46* 
47* 
* * 
*0*0 



* 

10 

107 

10S 

108 

*1 

21 

41 

24 

21 

36 

41 

34 

21 

40 

23 

40 

33 

41 





" : RETUR 

n,ios 

3*103 
32*107 
39*109 
6*40*2 
*9i»21 
»80*41 
*78*24 
»74*20 
33 



L<3 



7 * 



*59*41 
*64*33 
2*54*33 
1,50*41 
1*49*33 
0*48*32 
0*46*39 
1*36*41 



N 

22*107*23,107*24 

29*109*30*110*30*111,30 

33*107*34*106*35 

40*110*40, 111*40*111*41 

96*21 

1 * 9 , 22 , 1 * 89 , 23 * 1 * 89 , 24 

2*79,40*0*79*40 

2*73*23*0,78*23*2*77,22 

1*93*20,0*71*20 

1*69*36*1*63*34*1,68* 36 

2*58*40*0,53*40 

1,63*32*1*63*21*1*62*20 

0*51,21 

1*50*32*0*50*29,1*50*20 

0,49*39 

1*43,29*0*48*21*1,48,20 

1*45*38*1*45*33 

2*35*40*0*35*40*2,35*21 




Building Blocks for 
Microcomputer Systems, 
Dedicated Controllers 
and Test Equipment. 



R 2 l/0 

S-100 ROM, 

RAM & I/O 

BOARD 




ECT's R 2 l/0 is an S-100 Bus I/O Board with 3 Serial 
I/O Ports (UART's), 1 Parallel I/O Port, 4 Status Ports, 
2K of ROM with the 8080 Apple Monitor Program and 
2K of Static RAM. 

$295.00 




RM-10 
S-100 

RACK MOUNT 
CARD CAGE 



ECT's RM-10 is a rack mount 10 slot Card Cage with 
Power Supply, consisting of an ECT-100 rack mount 
Card Cage (19"W x 12.25"H x 8"D), the MB-10 Mother 
Board (with ground plane and termination) all 10 
connectors and guides and the PS-15A Power Supply 
(15A@8V, 1.5A@ ± 16V). $295 00 



Specializing in Quality Microcomputer Hardware 

Industrial • Educational • Small Business • Personal 

Card Cages, Power Supplies, Mainframes, CPU's, Memory, I/O, OEM Variations 



763 Ramsey Ave., Hillside, NJ 07205 



(201) 686-8080 



30 January 1981 © BYTE Publications Inc 



Circle 21 on inquiry card. 




-JIMS 




Q ATAia 




Atari* &Appl< 

ilc" software. 



A financial VP in Massachusetts is cutting the time it takes 
to prepare month-end reports from three days to three hours. 

A California company is replacing most of its time-share 
computer service with a personal computer and VisiCalc, 
saving at least $30,000 the first year. 

Thousands of other personal computer users are also sold 
on how VisiCalc is increasing their productivity. Besides saving 
time and money, they're simplifying their work and getting 
more information that helps them make better decisions. A 
typical user reaction comes from a New York dentist: 

"VisiCalc has become an integral part of my business" 

VisiCalc displays an "electronic worksheet" that auto- 
matically calculates nearly any number problem in 
finance, business management, marketing, sales, engi- 
neering and other areas. The huge worksheet is like a 
blank ledger sheet or matrix. You input problems by 
typing in titles, headings and your numbers. Where 
you need calculations, type in simple formulas 
(+,— , X,-r) or insert built-in functions 
such as net present value and averaging. 
As quickly as you type it in, VisiCalc 
calculates and displays the results. 

"I am extremely impressed with Visi- 
Calc's capability, flexibility and orderly 
presentation of instructions'.' 

So writes the director of a New York cor- 
poration. He appreciates VisiCalc's powerful 
recalculation feature. Change any number in 
your model and instantly all numbers affected by 
that change are recalculated and new results are 
displayed. You can ask "What if . . 7', analyzing 

Commodore is a registered trademark of Commodore 
Business Machines Inc., Atari is a registered trademark of 
Atari Inc.. Apple is a registered trademark of Apple 
Computer Inc. 



more alternatives and forecasting more outcomes. It really 
increases your decision-making batting average! 

When you finish, you can print a copy of the worksheet just 
as it appears on the screen and /or save it on diskette. 

"I like VisiCalc's ease of use" 

That response comes from a Utah businessman using Visi- 
Calc for production forecasts, financial report ratio analysis and 
job cost estimating. Ease of use is VisiCalc's best-liked feature. 
It's designed for a non-programmer, and has an extensive, easy- 
to-understand instruction manual. 

Users also like solving a wide variety of problems with 
VisiCalc . . . and solving them their way. VisiCalc can even 
justify the cost of a personal computer, according to a New 
Hampshire financial analyst: 

"VisiCalc is paying for itself over and over." 

VisiCalc is available for 32k Commodore PET/CBM, Atari 
800 and Apple disk systems. VisiCalc is written by Soft- 
ware Arts, Inc. 

See VisiCalc at your Personal Software dealer. 
For your dealer's name, call Personal Software Inc. 
408-745-7841, or write 1330 Bordeaux Drive, 
Sunnyvale, CA 94086: 

While there, see our other Pro- 
ductivity Series software: Desktop Plan 
and CCA Data Management System. 
They're like time on your hands and 
money in the bank. 




Circle 22 on inquiry card. 



AUGUST t?3G Volune s, HuHber 



The Atari 400/800 display list is 
actually a small program. 



WS5-C-C.1 



fl HCGRAM HILL 
PUBLICATION 



Photo 2: The BYTE logo as displayed by the Atari 400/800 run- 
ning the program in listing 2. 



8 BY 8 PIXEL 
SQUARE 



BINARY 



HEXADECIMAL 



DECIMAL 







1 1 





Figure 3: The assignment of values to create an elevated lower- 
case "c" character. 



Text continued from page 26: 

not uppercase and lowercase together — at least not in 
GRAPHICS 1 or 2. Since we want uppercase and lower- 
case together, we will have to redefine the character set. 

To do this, we must have some memory reserved for 
the new character set. Line 20 did this by fooling the 
operating system into believing that the top of memory 
(called RAMTOP) lies sixteen pages lower than it actual- 
ly does. This has reserved 4 K bytes for our use. The 
character set needs only 1 K bytes, but the display data 
cannot cross a 4 K boundary (without entailing difficul- 
ty), hence we must move the display list and display data 
down by an entire 4 K. The address of the beginning of 
our new character set is calculated in line 200 and is called 
ADDR. 

In line 210, we move the original character set (starting 
at address 57344 in ROM) into user memory. In line 220, 
we tell the operating system where the new character set 
is. In line 230, we move the uppercase characters into the 
positions previously occupied by punctuation. Our new 
64-member character set has uppercase and lowercase, 
but very little punctuation. In line 240, we define a new 
space character, as the original space character was part 
of the old punctuation group. We shall use the place 
previously occupied by the @ character for our space 
character. 

We next take this technique of defining our own char- 
acters one step further. We had earlier decided to elevate 
the lowercase "c" in "McGraw-Hill." To do this, we must 
redefine what a lowercase "c" looks like. This is done in 



line 250, with data coming from line 999. Obviously, this 
procedure can be greatly extended. The diligent program- 
mer can define any character set that can be expressed in 
an 8- by 8-pixel grid and POKE it into user memory 
directly (see figure 3). Greek, Cyrillic, or special technical 
character sets can be created in this way. 

We now have our display list and character set in 
order. We need only display our text. This is done start- 
ing at line 290. The first POKE suppresses the cursor for a 
neater display; the second POKE fools the operating 
system into believing that it is working in mode 0. This 
prepares the way for a straightforward POSITION and 
PRINT of the first text line. The only trick is that the line 
is positioned vertically according to the number of mode 
lines from the top of the screen. 

The next two text lines pose a particularly knotty prob- 
lem. We desire to print GRAPHICS 1 and 2 characters on 
mode lines 46 thru 52. Neither graphics mode allows so 
many lines; when we try to position the cursor onto line 
46 the computer will generate a "cursor out of range" 
error. Our only recourse is to POKE the character bytes 
directly into the display memory. We do this starting at 
line 310. First, we calculate the starting address of the dis- 
play memory (MEMST). Then we calculate the address 
where our characters are to be stored (CHRPOS). Our 
calculation relies on the fact that the characters are on the 
46th line and all previous lines used 40 bytes each. In 
more complicated situations, we would have to add up 
the byte requirements of all previous lines. This can get 
messy when a display mixes mode-1 or mode-2 lines at 20 
bytes per line with other modes that use 40 bytes per line. 
Fortunately, our case is simple. Once CHRPOS has been 
calculated, we POKE the character values into the dis- 
play data using a simple loop (line 320). Adding 60 to 
CHRPOS (line 330) skips three of our 20-byte mode-1 or 
mode-2 lines. We then POKE the character values for our 
third text line using the same technique we used in line 
320, except that a different character-value offset ( — 64 
instead of + 128) gives us green characters instead of red 
ones. Line 350 turns the characters back on. 

Conclusion 

The two major tricks we have demonstrated in this ar- 
ticle (modifying the display list and redefining the char- 
acter set) will greatly extend the graphics and display 
power of your BASIC programs. The Atari 400/800 run- 
ning BASIC alone has stunning graphics capabilities. 
With these tricks, the machine brings previously un- 
heard-of capabilities into the hands of the personal com- 
puter owner. Yet, we are still just trundling down the 
runway. There are even grander functions built into this 
machine — movable graphics objects for animation, ver- 
tical and horizontal fine scrolling, and display-list inter- 
rupts, to name a few. With these tricks in hand, we can 
soar beyond the limits of yesterday's color display and 
animation. ■ 



32 January 1981 © BYTE Publications Inc 



Circle 23 on Inquiry card. 



The Panasonic and Quasar 
Hand-Held Computers 

Beginning a New Generation 
of Consumer Computers 



Gregg Williams, Editor 

Rick Meyer, Friends Amis 

c/o BYTE 

70 Main St 

Peterborough NH 03458 



Arthur C Clarke talked about them 
in his futuristic novel Imperial Earth. 
Jerry Pournelle and Larry Niven 
talked about them in The Mote in 
God's Eye. The subject is hand-held 
computers that can run programs, re- 
mind you of upcoming appointments, 
and serve as portable intermediaries 
between you and large, immobile, 
mainframe computers. Are they still 
science fiction? No, the hand-held 
computer is here — and for less than 
the price of some color televisions. 

The HHC (hand-held computer) is 
a device about the size of a standard 
paperback book with two inches 
added to its longest dimension (see 
photo 1). Its weight is under a pound, 
yet it has the capabilities (when ex- 
tended with portable peripherals) to 
do anything that existing personal 
computers do. The device, developed 
jointly by the Japanese corpora- 
tion Matsushita (pronounced mat- 
SOOSH-ta) and Friends Amis of San 
Francisco, is being marketed in 
America by Panasonic and Quasar. 
Photographs in this article show both 



It is impossible to lose 
the work you are do- 
ing by pressing the 
OFF key. 



the Quasar and the Panasonic ver- 
sions. 

Description of the HHC System 

The Quasar/Panasonic HHC is an 
integrated package of hardware and 
software that has the ability to do 
anything that other personal com- 
puters do. The HHC unit has the 
following characteristics: 

• Dimensions: 22.7 by 3.0 by 9.5 cm 
(8 15 / 16 by 1 3 / 16 by 3% inches); 

• Weight: 397 grams (14 oz.); 

• 6502 microprocessor running at 
1MHz; 

• Sixty-five-key keyboard with two- 
key rollover; 



• 159 by 8 dot low-persistence LCD 
(liquid-crystal display); 

• Uninterrupted storage of all user 
programs and other data through use 
of a unique "power-down" circuit; 

• Redefinition of all keys during 
execution of an application program; 

• Redefinition of all characters 
displayed on the LCD display and 
printer during execution of an 
application program; 

• 2 K bytes of programmable mem- 
ory, expandable to 4 K bytes internal- 
ly or any practical limit (up to a 
theoretical limit of 4 megabytes) ex- 
ternally, by adding programmable 
memory peripherals; 

• 16 K bytes of internal ROM (read- 
only memory) with sockets for four 
program capsules containing up to 
64 K bytes of application programs 
or data (additional ROM, up to a the- 
oretical limit of 4 megabytes, can be 
added externally through ROM 
peripherals); 

• An internal real-time clock with a 
resolution of y 2S6 second; 

• A built-in nickel-cadmium battery 



34 January 1981 © BYTE Publications Inc 




How to tell if it's a White Computer. 



You see, it isn't always white. 
Until now, if you bought a White 
Computer it was dressed up as some- 
one else's system. Mow the White 
Computer is available under its own 
nameplate. 

And the features that make the 
White Computer the choice of many 
system builders also make the White 
Computer an excel tent choice for you. 

Features like White's guarantee to 
ship replacement parts within 24 
hours of your telephone call. CP/M® 
and MP/M™ operating systems. Full 
upgrade routes to multi-user and 
hard-disk performance. (Like the 
3-user 35 megabyte system shown.) 
And 8-bit or 16-bit configurations. 
Features that make the White Com- 
puter the reliable, high performance 



system you need for business, or 
software development, or industrial 
control uses. 

So if you buy a computer that's 
not white, it might still be White. But 
make sure. Because if it's not White, 
chances are you're paying more, for 
less computer. 

White Computers are now 
available from computer dealers 
nationally. Call or write for more 
information, and the name of your 
nearest dealer. 

CK/M is a registered trademark ol Digital Research. 
MI7M Is a trademark of Digital Research. 



White Computer Company A 1876 Industrial Way 
Redwood City, California 94063 A 415 364 7570 







Photo 2: The HHC and its peripherals. The HHC computer is in the center of the 
photograph. The peripherals are (clockwise, from upper left): a programmable-memory 
extender, the color television interface, the I/O driver (a distributor of bus signals from 
the HHC to other peripherals), an acoustic-coupler modem, a portable printer, a 
cassette interface, and a ROM expander. 



All functions are 

selected via a set of 

nested menus. 



enough current to retain the contents 
of the HHC's display image and 
CMOS (complementary metal-oxide 
semiconductor) memory and to pre- 
serve the real-time clock and key- 
board functions. A side benefit of this 
feature is that it is impossible to lose 
the work you are doing by pressing 
the OFF key; when you press the ON 
key, the computer resumes whatever 
it was doing before it was turned off. 

A specially designed 44-pin bus 
connector allows you to connect and 
disconnect the HHC and its periph- 
erals while all the components are 
powered up. Because of this feature, 
the HHC and its peripherals can join 
their respective data, address, and 
control buses without destroying data 
in either unit. As an additional safety 
feature, the piezoelectric beeper in- 
side the HHC sounds if the HHC finds 
any loose connectors. 

The ability to connect and discon- 



nect modules while the power is on is 
very important because it allows the 
unit to be used in a variety of com- 
binations without worrying that data 
will be destroyed by doing so. The 
HHC and its peripherals can be con- 
sidered as interconnecting modules, 
and you can effectively forget that 
they contain volatile data. For exam- 
ple, when future program-develop- 
ment capsules become available, you 
will be able to write a program while 
traveling, then debug it more easily 
by hooking the HHC into the color 
TV adapter and printer. Data can 
also be entered into an HHC memory 
peripheral that may then be detached 
from the HHC and given to another 
HHC owner. He or she can plug it in- 
to another HHC and access the data 
that was stored. 

Friends Amis has invented a par- 
ticularly elegant solution to the 
packaging of programs in ROM 
(read-only memory). This solution 
also allows denser storage of informa- 
tion than was previously possible. 
The HHC uses 24-pin ROMs that are 
packaged in a plastic carrier around 
which the pins of the ROM are bent 
(see photo 3). This combination is 



called an Amis Memory System Cap- 
sule (patent pending). (When a cap- 
sule is inserted into the back of the 
HHC, the flat base of each pin makes 
contact with the socket. This insures 
a good electrical contact without the 
usual fragility of integrated circuit 
pins.) Since a minimal amount of 
hardware is used to package the 
ROMs, more can fit inside the small 
body of the HHC. 

These capsules have already been 
used in the Craig, Panasonic, and 
Quasar language translators (also 
developed by Friends Amis), and in 
the Friends Amis point of 
information display computer. Cap- 
sules can contain data to be 
manipulated (eg: words in a French 
language capsule), application soft- 
ware (eg: a capsule of game pro- 
grams), programming languages (eg: 
a BASIC capsule), or any other data 
that the computer can act upon. Cap- 
sules can hold 2 K, 4 K, 8 K, or 16 K 
bytes of information. The 16 K-byte 
ROM allows an unprecedented 
amount of data to be stored in a small 
space. The large amount of informa- 
tion that can be stored in the HHC is 
increased by its internal use of a 
threaded language and by the ap- 
plication of a set of data compression 
techniques. 

Human-Engineered Features 

As a direct result of the manufac- 
turers' desire to design a computer 
specifically for the mass market, the 
Quasar/Panasonic HHC was devel- 
oped with a heavy emphasis on 
human engineering. This design 
philosophy is reflected in the opera- 
tion and features of the HHC. 

The keyboard has always been a 
crucial interface between the user and 
the computer, and the popularity of 
several existing microcomputers has 
been largely influenced by the us- 
ability of their keyboard. This fact, 
coupled with the small size of the 
HHC, makes it necessary for the 
HHC keyboard to be as usable as 
possible. We feel that the designers 
have achieved this objective. 

[Despite my initial disbelief that a 
keyboard this small could be of any 
practical use, I was soon convinced 
that the HHC keyboard is easy to use 
and that, given some familiarity with 
it, I could use the keyboard without 
being distracted from the task at 
hand... GW] 

Photo 1 indicates that the keys on 



36 January 1981 © BYTE Publications Inc 



pack that supplies all power to the 
unit; 

• Internal shielding against RF (radio- 
frequency) interference in compliance 
with the new regulations from the 
Federal Communications Commis- 
sion; 

• An internal set of application pro- 
grams that includes a four-function 
calculator, a free-form file system and 
editor, as well as several other func- 
tions. 

In addition, the capabilities of the 
HHC are greatly extended by an in- 
tegrated system of intelligent periph- 
erals that include: 

• A bus expander through which 
other modules are connected to the 
HHC; 

• A portable thermal printer that 
prints 16 characters per line; 

• A ROM extender that allows you to 
attach an additional four program or 
data capsules; 

• A programmable-memory extender 
that allows you to add additional 
memory to the HHC; 

• A 110/300 bps modem and tele- 
computing program through which 
the HHC can act as a remote terminal 
to other computers and to large infor- 
mation utilities and data bases; 

• A cassette interface module that 
transfers data to a microcassette 
recorder at 1200 bps; 

• A color television interface that 
allows a display of 16 lines of 32 char- 
acters each or up to 48 by 64 pixel 
(picture element) graphics in eight 
colors and black. 

When connected to the HHC, all of 
the above peripherals can fit in a 
custom case the size of an average 
attache case, or they can be intercon- 
nected to make a flat, rigid, easily 
portable combination. With the ex- 
ception of the color television inter- 
face, the HHC and the peripherals 
can operate without connections to 
any outside power source, thus mak- 
ing the system truly portable and 
hand-held. Photo 2 shows the HHC 
and several of its peripherals. 

Innovations in the HHC 

The Panasonic/Quasar HHC em- 
bodies several technical break- 
throughs. Without these develop- 
ments, a computer as small and as 
powerful as the HHC could not have 
been built. 

One of the most important innova- 





Photo 1: The Panasonic and Quasar HHCs (hand-held computers). Both units 
shown are prototype models and will have the same keyboard layout in the 
finished versions. 



tions in the HHC is the proprietary 
"power-down" circuit that allows the 
HHC to use the popular 6502 micro- 
processor in a hand-held device. In 
the past, manufacturers have 
designed hand-held products around 
microprocessors like the 1802. Such 
devices use a very small amount of 
current and can be powered by bat- 
teries, but they force the designer to 
use a slow microprocessor with a 
weak instruction set. 

Designers have been prevented 
from using the more popular micro- 



processors because of their high cur- 
rent drain: a conventional 6502-based 
circuit (using the same batteries as the 
HHC) would discharge them in about 
two hours. But, with this power- 
down circuit and additional hardware 
innovations, the amount of current 
needed to power the HHC in both its 
fully functioning and "off" (powered- 
down) modes is drastically reduced. 
A related feature of the HHC is that 
when the OFF button has been 
pressed, the computer is still on. It is 
in a dormant state that uses only 



January 1981 © BYTE Publications Inc 35 



the HHC are arranged in the standard 
typewriter format. In addition, a key 
can be pressed without pressing any 
adjacent keys, so it is possible to 
touch-type on the HHC, regardless of 
individual finger width. This fact 
allows the HHC to be used in text ap- 
plications — an area not practically 
accessible by any other device of its 
size. 

Another powerful feature of the 
HHC is its ability within an applica- 
tion program to redefine any key 
position to any function. With the 
addition of a keyboard overlay, this 
can provide a keyboard that is com- 
pletely suited to a given application. 
It was the intention of the HHC de- 
signers that no application, regardless 
of complexity, would require mem- 
orization of command language or 
special key sequence (like control-P 
for print) to perform a function avail- 
able to the computer but not allotted 
a key. With redefinable keys and 
keyboard overlays, this will never 
happen. 

Three special keys, labeled fl, f2, 
and f3, can be assigned to be any se- 
quence of keystrokes, including most 
function keys. When one of these 
keys is typed, its current definition is 
input as if the sequence of keys had 
been typed by the user. The defini- 
tions are processed as interrupts and 
are independent of the program in 
use. Thus, they can be used with any 
present or future programs, even 
those written in BASIC or SNAP (the 
two computer languages currently 
planned for the HHC). For example, 
one key can be assigned to a sequence 
of calculations and/or constant 
values for use with the built-in 
calculator. Another key can be used 
to enter repetitive text in the memory 
bank text editor or to create special 
functions such as search-and-replace. 
Another definition can be used to 
make a commonly used sequence of 
menu selections to reach a frequently 
used program. 

A unique feature of the HHC is the 
HELP key. When this key is pressed, 
you are prompted by the LCD display 
to press any key to find its definition. 
When a key is pressed, the function is 
given in a complete sentence of up to 
80 characters. For example, pressing 
the HELP key followed by the 
STP/SPD key causes the message 
"STOP / ENTER 1-9 FOR SPEED" to 
be displayed. 

Four HHC keys are used to indicate 



LEFT, RIGHT, UP, and DOWN. In 
most programs, these keys are used 
for cursor control and horizontal and 
vertical scrolling. Since the HHC's 
built-in display shows only one short 
(26-character) line at a time, it is im- 
portant to be able to "steer" the 
display through a larger page or list 
of material. The display is often used 
as a window into a larger virtual 
space (as is done in the popular 
VisiCalc program), and the four 
direction keys, which are auto-repeat 



keys, move the window in any direc- 
tion. Another key, STP/SPD (stop/ 
speed), allows you to freeze and con- 
tinue any program, like a run/ 
stop switch, and to adjust the rate of 
information display. 

The HHC also has INSERT and 
DELETE keys that allow text material 
to be changed. The HHC normally 
displays a solid rectangular cursor, 
but when you enter the insertion 
mode, the cursor changes to a blink- 
ing checkerboard cursor. Similarly, 



WORD 


FIRST 
NUMBER* 


LETTERS BORROWED 
FROM LAST WORD 


FIRST 
LETTER 
NOT 
COPIED 


SECOND 
NUMBER* 
(COUNT 
FORWARD) 


NEXT LETTER 
OF NEW WORD 


REMAINING 
LETTERS OF 
NEW WORD* 


SLOW 


-_ 


__ 


__ 


__ 


__ 


__ 


SLUMP 


2 


SL 


+ 


6 = 


U 


MP 


SLY 


2 


SL 


u + 


4 => 


Y 


— 


SMALL 


1 


S 


L + 


1 = 


M 


ALL 


SMART 


3 


SMA 


L + 


6 = 


R 


T 



Figure 1: Compression of an alphabetized list. The tables of alphabetized lists within 
the HHC are kept as small as possible by using numbers to keep track of the number of 
letters shared from the previous word and the number of letters between the first dif- 
ferent letter in the new word and its counterpart in the previous word. Note that the 
shaded letters on a line make up the word being encoded, but only the two numbers and 
the letters in the last column (all marked with an asterisk in their table headers) are ac- 
tually stored in the encoded table. The dashes indicate an empty entry (as in the line for 
the word SLY). The first line is all dashes because it does not have a previous line to 
refer to; in practice, all the letters of the first entry must be normally encoded. 




Photo 3: Close-up of an HHC program capsule. The program capsule is actually a stan- 
dard 24-pin integrated circuit with its pins curled around a plastic harness. Its length is 
3.65 cm (l 7 /i b inches). 



January 1981 © BYTE Publications Inc 37 




Photo 4: The Quasar HHC connected directly to its acoustic coupler. The combina- 
tion, which is also available in the Panasonic HHC system, is a self-contained portable 
computer terminal. 



The computer executes 

a FORTH-IIke language 

called SNAP. 



when you enter the deletion mode, 
the cursor changes to a rectangular 
outline cursor. These useful features 
give you visual feedback regarding 
the mode that the computer is in. 

Other keyboard-related features 
are the search and locate commands 
available within the memory bank 
electronic file system. These features 
are available in two modes — context 
and initial search. A context search 
searches for a match to the given 
character string anywhere in the file, 
while an initial search searches for a 
match beginning with the first char- 
acter of each record in the file. The 
former method allows maximum 
searching power, but the latter pro- 
vides a faster search when the posi- 
tion of the string to be matched is at 
the beginning of each record (eg: 
when the file contains last names and 
telephone numbers and you are given 
the last name). 

Other strong keyboard features of 
the HHC are the size and placement 



of certain keys. The SPACE and 
ENTER keys are in their traditional 
positions, and both are wider than 
the other keys for ease of use. Also 
notice from photo 1 that the CLEAR, 
ON, and OFF keys are located five 
rows to the right of the rightmost let- 
ter key, and at least two rows to the 
right of any other key. Although the 
consequences of hitting these keys by 
accident are less critical than on other 
personal computers (more on that 
later), the keys were placed there to 
minimize the danger. 

Finally, the behavior of the SHIFT 
and LOCK keys should be mention- 
ed. In applications where the pro- 
gram differentiates between upper- 
case and lowercase letters, an upper- 
case letter is obtained by hitting the 
SHIFT key, followed by the key to be 
shifted. The HHC is locked into up- 
percase by hitting the LOCK key after 
the SHIFT key. You can return to 
lowercase by hitting either the SHIFT 
or LOCK keys. The LOCK key can 
also lock the four cursor-control keys 
and the INSERT and DELETE keys. 

The Menu and Other Features 

To allow for use of the Panasonic/ 
Quasar HHC with minimal prior 
knowledge of the machine, all func- 



tions are selected via a set of nested 
menus. The first menu that appears 
when the computer is turned on is 
called the primary menu. It displays 
the available internal and capsule 
program choices (eg: clock/secretary, 
program capsule, etc) with a 1-digit 
number assigned to each. A choice is 
selected by pressing the correspon- 
ding digit key. If the selected applica- 
tion allows choices of its own, its 
menu is displayed in the same way. 
This process is repeated until an ex- 
ecutable program is reached. Pressing 
the CLEAR key causes the HHC to 
display the second menu (the one 
immediately after the primary menu). 
Pressing the CLEAR key twice causes 
the HHC to return to the primary 
menu. 

The HHC computer contains a 
piezoelectric beeper that can produce 
either a click (to provide audible feed- 
back to an event, usually a keypress) 
or a tone within a four-octave range. 

Squeezing More into Less 

There has been recent publicity on 
threaded languages — most visibly 
FORTH. (See the special language 
issue on FORTH, August 1980 
BYTE.) Threaded languages offer 
program compactness and speed of 
execution halfway between those of 
machine language and a high-level 
language like BASIC, while offering 
the programming ease and language 
transportability of high-level lan- 
guages. 

The Quasar/Panasonic HHC is 
actually a hardware machine that 
executes a FORTH-like language 
called SNAP, in addition to 6502 ma- 
chine code. The HHC uses SNAP for 
every function that it performs, from 
the display of characters on the LCD 
readout to the handling of interrupts 
from the peripherals. When timing is 
critical in a specific routine, such as 
interrupt handling for high-speed pe- 
ripherals, SNAP allows any portion 
of itself to be coded in assembly 
language for maximal speed. 

SNAP, like other threaded lan- 
guages, is defined in terms of a given 
set of operators (which are analogous 
to the operation codes of a given 
microprocessor). SNAP programs are 
simply lists of these operators, so 
these programs (including applica- 
tions programs embedded in program 
capsule ROMs) may be used without 
change on any machine that executes 
the SNAP language, provided no ma- 



38 January 1981 © BYTE Publications Inc 



chine code is used. This protects the 
sizable programming effort put into 
the HHC against hardware innova- 
tions in future versions of the HHC, 
while maintaining a body of pro- 
grams that execute quickly and use 
little memory. 

Another way in which the execu- 
tion time of programs is decreased is 
through the use of interrupts for the 
HHC keyboard and all peripherals. In 
contrast to other computers which 
use polling (ie: they periodically 
check the device to see if it needs 
computer time), the HHC peripherals 
and keyboard generate interrupts 
when they require attention from the 
6502 microprocessor. In this way 
several peripherals can be serviced at 
once. The HHC slows down only 
when it is interrupted to do specific 
work and is therefore faster than 
computers that waste time polling in- 
active devices. The HHC peripherals 
that require serial data all use 
separate UART (universal asyn- 
chronous receiver-transmitter) in- 
tegrated circuits for this purpose. 

Given the 64 K-byte maximum ad- 
dressing ability of the 6502 
microprocessor, the HHC must 
somehow pack more memory into 
less space. It does so, using the 
familiar technique of bank-switching. 
Three banks of memory, hexadecimal 
2000 to 3FFF, 4000 to 7FFF, and 8000 
to BFFF, are bank-switched. This 
means that several blocks of up to 
16 K bytes of memory could be 
assigned to one of the above address 
areas, with electronic circuitry en- 
abling only one such block to be 
active at a time. 

The program capsules that insert 
into the back of the HHC all map into 
the same 16 K-byte address area: 
hexadecimal 4000 to 7FFF. Only one 
capsule is active at a time and is 
selected from the HHC primary 
menu. This area is also used for user 
data and programs. 

The 16 K-byte area from hexa- 
decimal locations 8000 to BFFF is used 
for external programmable memory 
banks. Since this bank is in a different 
address area from ROM banks, many 
ROM-based programs can reference 
data in programmable memory with- 
out bank-switching. 

The 8 K-byte address area (from 
hexadecimal locations 2000 to 3FFF) 
is used by the specialized firmware 
that is contained in each HHC 
peripheral. When a given peripheral 
is being used, the firmware that con- 



Letter 

E 

T 

I 

O 

N 

S 



Huffman Code 

000 

001 

010 

0110 

0111 

1000 



(a) 



Code 


Bit(s) to 
Be Matched 


Comments 


100111 





--no match 


01001 1 1 


01 


--no match 


0100111 


010 


--matches I 


(I1P_111 





--no match 


(1)011 1 


01 


-no match 


(DQ1J1 


011 


-no match 


(1)01 1 1 


0111 


-matches N 


(I) (N) 


done 


--message is IN 



(b) 



Table 1: An example of Huffman coding. Table la shows an example Huffman 
code for several letters. Table lb shows how the code 0100111 is decoded into the 
letters I and N. Bits are taken from the left side of the remaining binary string until 
the sequence of bits matches one of the table entries. Notice in table la that the 
code for no letter is a beginning substring of the code for another letter. (This, for 
example, accounts for the fact that no letter is given to the bit string 011 — it would 
conflict with 0110, the code for the letter O.) Every Huffman code (of which there 
are an infinite number) is constructed so that no two letters can be confused with 
each other. If the letters are assigned codes in the order of their decreasing fre- 
quency for the text to be decoded, a Huffman code permits the maximum data 
compression possible. 



Table Number of Elements 

Rank(N) in Table ( = 2~) 



1 2 

2 4 

3 8 

4 16 

5 32 

6 64 



Number of Bits 
In New Permutation 

Algorithm 
(F(N) = 2~ + 2F(N-1)) 

1 

6 = 4 + 2(1) 

20 = 8 + 2(6) 

56 = 16 + 2(20) 

144 = 32 + 2(56) 

352 = 64 + 2(144) 



Number of Bits 

In Ordinary Look-up 

Table (=N2 N ) 



2 

8 

24 

64 

160 

384 



Table 2: Efficiency of the permutation algorithm given in figures 2 through 4 and 
the text box. As can be seen from the last two columns, this algorithm uses fewer 
bits to define a given permutation. The ordinary look up table uses a table 2" 
entries long by N bits long to look up the value (from to 2 N —1) that a given 
element (in the same range) is permuted to. 



trols its communication with the 
HHC is selected and used. This area 
also contains the memory-mapped 
contents of the video display when 
the HHC is connected to the color TV 
interface. 

In both 16 K-byte bank-switched 
areas it is possible to reference a pro- 
gram or a program/data combination 
that is more than 16 K bytes long. 
The program (or program and data) 



is divided into 16 K-byte blocks, all 
of which map into the same area. 
Under program control the software 
can then jump between 16 K-byte 
blocks by writing the appropriate 
value to a location in the HHC that 
determines which block is currently 
selected. 

Text Compression in the HHC 

The increase in data storage caused 



January 1981 © BYTE Publications Inc 39 



a) 



l 

2 




b) 

Figure 2: Two possible outcomes for the 
permutations of a two-element list. See 
the Mapping Algorithm text box for 
further details. 

by the use of SNAP and 16 K-byte 
program capsules is significant. But 
the increase caused by the use of data 
compression techniques is even more 
significant, almost doubling the 
amount of information that can be 
stored in an HHC data capsule. A 
variable word-length code and in- 
creased data compaction through 
context are the two techniques used. 

In traditional data storage, one 
character of information is stored in a 
byte (or 8 bits or binary digits) of 
computer memory. Letters, numbers, 
and punctuation are stored in the 
ASCII (American Standard Code for 
Information Interchange) format, 
which uses 7 bits per character. Using 
a method developed by Friends Amis 
that modifies what is called a Huff- 
man code, variable bit-length codes 
can be devised for the characters to be 
encoded such that frequently used 
characters will be given shorter codes 
(called codons), thus decreasing the 
average number of bits used per 
character. Table 1 shows an example 
of a standard Huffman code (there 
are an infinite number of such codes). 

Because of this variable-length 
coding, the computer's memory is 
seen as a long string of bits. Bits are 
read from left to right (figuratively 
speaking) until the bits read match 
the codon for any character in the set. 
(Codons are generated by rules that 
guarantee that a beginning string of 
bits can match the codon of only one 
letter in the set.) Codons are also 
devised so that the most frequently 
used letters have the shorter represen- 
tations and are also near the top of 
the look-up stack. Because the num- 
ber of look-up entries read before a 
match occurs is kept to a minimum 
(on the average, slightly more than 
eight entries), the decoding process 



does not slow the machine down. 

A further measure of compression 
is made by modifying the look-up 
procedure to be sensitive to the con- 
text of the previous letter. For exam- 
ple, even though the most frequently 
used letters in normal English text are 
(in decreasing frequency) E, T, I, O, 
N, and so on, if the previous letter 
looked up was Q, then the letter U is 
most probably the next letter and so 
should be close to the beginning of 
the look-up table. Within the HHC, 
the letter-decoding routine uses the 
previously decoded letter to index 
one of several look-up tables. In this 
way, encoded characters can be re- 
presented in even fewer bits than 
would otherwise be possible using 
straight frequency-determined co- 
dons. 

Two more techniques are used 
within the HHC to decrease the 
number of bits used to represent 
character information to a final 
density of just over 4 bits per char- 
acter. Although these techniques 



were developed to deal with alpha- 
betized lists of words (for the Friends 
Amis language translator), it is possi- 
ble to use them to compress nonal- 
phabetized text in some situations. 

The first technique replaces the 
beginning of each word (except the 
first word in a list) with two numbers. 
The first number tells how many let- 
ters to borrow from the previous 
word. The second number tells how 
many letters away the first non- 
matching letter is from its counterpart 
in the previous word. For example, if 
the words are SMALL and SMART, 
the following is stored for the word 
SMART: 3 (telling the computer to 
borrow SMA from the word 
SMALL); 6 (telling the computer to 
count forward six letters from the L in 
SMALL to arrive at the R in 
SMART); the encoded letter T 
(ending the encoding of the word 
SMART). (See figure 1 for other ex- 
amples.) Because the two numbers 
(contained in 3 and 4 bits, respective- 
ly) take up fewer bits than the letters 



The Mapping Algorithm 

It is sometimes profitable to 
maintain a list of words in alpha- 
betic order but to be able to 
retrieve them in some other pre- 
specified order. The problem then 
becomes one of finding the most 
compact way of specifying a per- 
mutation of N elements from (l, 2, 
3, . , N) to some other ordering. 

The algorithm used within the 
Panasonic /Quasar HHC requires 
that the list be a power of 2 (ie: 
have 2, 4, 8, 16, 32, 64,... ele- 
ments). The algorithm can be con- 
sidered as a recursive set of pair 
switchings. The permutations of a 
list of two elements can be re- 
presented by 1 bit of informa- 
tion—say, aO to represent that the 
elements are not switched, eg: (1, 
2) becomes (1, 2); and alto repre- 
sent that the elements are switch- 
ed, eg: (1, 2) becomes (2, 1). This is 
represented pictorially in figure 2, 
where a box represents 1 bit of in- 
formation. 

The diagram in figure 3a is used 
with a list of four elements. The 
upper-lefthand box is always filled 
in with an equal sign (=). The in- 
put arrangement, usually (1, 2, 3, 
4), is substituted for INI thru IN4, 
and the desired permutation is sub- 



stituted for OUTl thru OUT4. The 
boxes in the first and third columns 
are filled in with either equal signs 
(=) or cross signs (X), leaving the 
boxes in the second column for 
last. 

Consider the example of permut- 
ing the list (1, 2, 3, 4) to become (4, 
1, 3, 2). Given the interconnections 
between boxes and the constraints 
given above, the only path that 
can be taken from 1 to 1 goes 
through the top middle box (in a 
manner not yet specified) and to 
the righthand side through a cross 
in the upper-right box, as shown in 
figure 3b. In figure 3c, the element 
4 is traced from box A to box B. 
Similarly, element 3 is traced from 
box B to box C, and element 2 is 
traced from box B to box S, where 
we started. 

Given the conditions shown in 
figure 3c, it is a simple task to fill 
in the middle columns, thus com- 
pleting the diagram. The finished 
diagram is shown in figure 3d. 
Through use of this diagram, the 
list (1, 2, 3, 4) can be permuted to 
the list (4, 1,3,2) using 6 bits of in- 
formation (1 bit for each of the six 
boxes). 

Study of an eight-element list ex- 
ample illustrates the recursive 



40 January 1981 © BYTE Publications Inc 



they replace, this method can repre- 
sent the same text in fewer bits. 

The last technique saves space in 
that it allows alphabetized lists to be 
used in a different order. (For exam- 
ple, in language lists a given set of 
words is mapped from the sequential 
order in its alphabetized list to a 
semantic order in a list of words of 
equivalent meaning available in each 
language list; this is done so that the 
computer can translate a given word 
to its equivalent in another language.) 
With this technique, a list of 2 N 
elements can be permuted into any 
other arrangement of the same ele- 
ments by a relatively small number of 
bits of information (see table 2). Refer 
to the Mapping Algorithm text box 
for the details of this algorithm. 

The Real-Time Clock 

One of the most important internal 
features of the Panasonic /Quasar 
HHC is its real-time clock and event 
sequencer. The real-time clock exists 
in memory as a 40-bit number stored 



method that is used to generate the 
final structure for longer lists. 
Figure 4 shows a mapping of the 
list (1, 2, 3, 4, 5, 6, 7, 8) to (6, 3, 8, 
1, 7, 5, 4, 2). As before, box S is 
marked with an equal sign. Boxes 
in the first and last columns are 
then filled in; this can even be done 
with no knowledge of the contents 
of boxes X and Y. The boxes A 
through G are filled in alpha- 
betically. Note that when these 
boxes are filled, the boxes X and Y 
become "black boxes" that map 
four-element lists into another 
ordering. These boxes are then 
solved as shown in figure 3, and 
the permutation of eight elements 
is now solved. The final solution 
has twenty boxes: eight as shown 
in figure 4, plus six boxes each for 
boxes X and Y. 

Larger lists are solved in an ana- 
logous way, with a list of 2 N 
elements first filling the 2 N boxes in 
the first and last columns, followed 
by the solution of the two middle 
boxes, each of which permutes a 
list of 2' elements. Table 2 shows 
the number of boxes (or bits) nec- 
essary to solve larger permuta- 
tions. 




•0UT2 



•0UT3 



-0UT4 






© 

















1 


P 


1 


X 








3 


3 













Figure 3: Solving a four-element permutation problem as a network of binary deci- 
sions. Figure 3a shows the initial configuration used in the solution of any four-element 
permutation. Figures 3b, 3c, and 3d show steps in the solution of this problem. See the 
Mapping Algorithm text box for further details. 



January 1981 © BYTE Publications Inc 41 



in 5 contiguous bytes of program- 
mable memory, supported by a hard- 
ware counter that can be preset. An 
increment of one unit in this number 
represents a time change of 1/256 sec- 
ond (about 4 milliseconds), so that 
the 40-bit number represents the 
number of 1/256 second intervals 
that have elapsed since the computer 
was permanently turned on. (Given 
the above figures, a 40-bit number 
will represent a time period of ap- 
proximately 139 years.) 

In keeping with the design philos- 
ophy of burdening the 6502 micro- 
processor with as few tasks as possi- 
ble, the real-time clock was designed 
to require the generating of as few in- 
terrupts as possible. Another area of 
memory contains a signed 23-bit 
counter circuit that automatically 
counts down to at a rate of one 
count every 1/256 second. Normally, 
when this timer reaches (once every 
2 23 /256 seconds, or about 9 hours), it 
generates an interrupt that adds the 
same amount (about 9 hours) to the 
40-bit clock number. However, if any 
program needs to access the real-time 
clock, the appropriate count based on 
the value in the 23-bit counter can be 
added to the 40-bit clock number and 
the 23-bit counter can be cleared, thus 
updating the clock to its correct 
value. 

Associated with the real-time clock 
is an event queue in which future 
events are stored as 40-bit numbers 
along with instructions to be carried 
out when the 40-bit clock number 
reaches that value. Internally, the 
operating system software can use 
this event queue to manage a set of 
asynchronous events with a mini- 
mum of processing. Application pro- 
grams can use the event queue, as can 
users programming on the HHC. 

Design for Component 
Interaction 

The Quasar /Panasonic HHC was 
designed to be compatible with both 
existing and future hardware and 
software. Because of this, the mem- 
ory usage of the computer had to be 
planned to provide maximum flex- 
ibility. 

In most microcomputer systems, 
there are fixed memory locations or 
I/O (input /output) ports assigned for 
specific hardware peripherals. The 
limitation of this approach is that the 
entire memory mapping must be fore- 
seen; otherwise the ability to include 



Data compression 
techniques in the com- 
puter almost double 
the amount of Informa- 
tion that can be stored 
in a given number of 
bits. 



future peripherals is questionable. 
The HHC does not make any fixed 
assignments. Instead, 4 bytes for each 
peripheral are dynamically assigned 
as I/O and status locations for all cur- 
rently connected peripherals each 
time the clear key is pressed, so any 
number of different peripheral types 
can be accommodated without run- 
ning into memory map conflicts. 

This flexible system of directing in- 
put and output allows the HHC to 
offer a more commonsense approach 
to dealing with devices like printers, 
modems, LCD displays, and other 
devices. In most computers, special 
commands must be given to direct in- 
put and output to specific devices, 
and even then you may not be able to 
distribute it to several devices. For ex- 
ample, a special command, LPRINT, 
must be used to get either the Radio 
Shack TRS-80 or the Atari 400 or 800 
to print information on their 
associated printers, and it is impossi- 
ble to get a program to print on both 
the video display and the printer 
without using both PRINT and 
LPRINT statements. With some limit- 
ations this can be done with the 
Apple computer, but only with the 
correct interface board and the 
correct PR#N command. 

The attitude taken by Friends Amis 
is that you shouldn't have to 
remember extra information (which is 
often complicated by being condi- 
tional on what the computer is cur- 
rently doing). With the HHC com- 
puter, the use of I/O devices can be 
changed by pressing the I/O key and 
enabling or disabling the appropriate 
devices from a menu displayed by the 
HHC. You can even, for example, in- 
terrupt a running program to enable 
the printer, and resume the program 
without error; from that point on, 
both the current display device (the 
LCD display, color TV, or other 
device) and the printer display 
whatever the program tells them to. 
This method allows HHC programs 



to be independent of the I/O devices, 
and it allows the use of future 
peripherals with current software. 

Application Software 

The Panasonic/Quasar HHC in- 
cludes several application programs 
that are contained in the same built-in 
read-only memory devices as the 
operating system. These programs 
implement a calculator, a clock/ 
secretary, and an electronic file sys- 
tem and editor. Each of these pro- 
grams is called from the primary 
menu of the HHC. 

The calculator program, when 
selected, transforms the HHC into a 
standard four-function calculator 
that adds, subtracts, multiplies, and 
divides. The calculator can store one 
number and has keys to add to, sub- 
tract from, clear, and recall memory. 
It also has a percent key. 

The clock/secretary uses the real- 
time clock that knows the time of 
day, the day of the week, and the 
date (day, month, and year). A clock 
option within the clock/secretary 
allows the time and date to be dis- 
played and continuously updated on 
the LCD display window. Otherwise, 
the clock/secretary can be used to 
keep track of future events. You can 
specify a time for the clock/secretary 
to activate itself, and include an op- 
tional reminder message. When that 
time arrives, the HHC sounds a mu- 
sical tune regardless of its current 
task; you can then perform an "ac- 
knowledge" operation and see the 
message associated with the event. 
The number of events and messages 
that the clock /secretary can hold is 
limited by the amount of program- 
mable memory in the HHC. 

The "memory bank" is the nick- 
name of an electronic file system and 
editor within the HHC. You can enter 
lines (or records) of up to 80 char- 
acters of ASCII information, group 
them to make files, and modify and 
list these files. Any file can be edited 
with a powerful cursor-controlled 
editor that allows insertion and dele- 
tion of characters or lines at the cur- 
rent cursor position. With the 
SEARCH key, you can also retrieve 
records from a file based on a char- 
acter string to be matched. 

Memory bank files can have any 
number of records, with each record 
holding up to 80 characters. The size 
and number of files that can be stored 
depends on the amount of program- 



42 January 1981 © BYTE Publications Inc 



mable memory in the HHC. The cur- 
rent model of the HHC has somewhat 
less than 1500 bytes of memory for 
this purpose, but the amount of 
memory in the HHC can be expanded 
with a battery-powered 4 K-byte 
memory extender peripheral. Future 
models will accept more program- 
mable memory in the form of cap- 
sules that fit into the same sockets as 
the read-only memory capsules. 

The Extended HHC 

The Quasar/Panasonic HHC, 
when combined with its line of pe- 
ripherals, has the ability to perform 
any function that existing personal 
computers do, while retaining the 
characteristics and advantages of a 
hand-held unit. The following sec- 
tions describe two of the most in- 
teresting peripherals — the color tele- 
vision interface and the modem. 

The color television interface is the 
only peripheral that requires connec- 
tion to an AC power line. But since 
the interface is also connected to a 
color TV, this is hardly a limitation. 
Once the interface is connected, out- 
put can be routed to the TV through 
the use of the I/O key. 

Through the color TV, the HHC 
will display 16 lines of 32 characters 
each. Characters can be displayed in 
several combinations (orange or 
green characters on black, or black 
characters on either an orange or a 
green background). Several kinds of 
characters can be displayed: upper- 
case and lowercase ASCII letters; 
numbers and punctuation; graphics 
patterns; and katakana characters (a 
set of phonetic characters used by the 
Japanese). All characters are created 
in a 7 by 9 dot matrix. 

The color TV interface offers two 
modes of color graphics: 32 by 64 pix- 
els, or 48 by 64 pixels. The interface 
allows for black and eight colors 
(red, blue, green, yellow, orange, 
magenta, cyan, and buff). 

The color TV interface contains a 
built-in RF (radio-frequency) modu- 
lator, as well as 1.5 K bytes of 
dynamic memory organized as two 
software-selectable screen images. 
The connection from the interface to 
the HHC is an interrupt-driven par- 
allel connection. 

The modem, which connects to the 
HHC through an interrupt-driven 
parallel interface, is acoustically 
coupled to a standard telephone 
handset (see photo 4). Its options — 





O 








© 




1 




1 


X 


6 










4 


1 
















O 






Q 




3 

4 


X 


/ \ 6 
\ / 7 


7 / \ 

4 \ / 


X 






© 



© 



© 



Figure 4: Partial solution of an eight-element permutation problem. Each of the boxes 
in the first and last columns is filled in first. The solution of this problem is then finished 
by the solution of two four-element permutations as given by the numbers on both sides 
of the boxes marked X and Y. 



110 or 300 bps (bits per second) data 
transfer rate, full- or half-duplex 
transmission, answer or originate 
mode, number of start and stop bits, 
and parity — are all selected by soft- 
ware. In a daring departure from con- 
ventional modems, the HHC modem 
has no visible switches to set any of 
its options. This forces the software 
to control all the options and leaves 
nothing for you to worry with (or set 
incorrectly). 

The HHC modem, like other HHC 
peripherals, is responsible for supply- 
ing standard input and output rou- 
tines. (By using a uniform software 
interface for all peripherals, the HHC 
can be expected to work with periph- 
erals that have not yet been 
designed.) Since the modem can be 
used in several ways, it is supplied 
with a socket in which to place a pro- 
gram capsule for a given application. 
The first capsule to be produced for 
the HHC modem is called 'Telecom- 



puting" and it will allow the HHC to 
be used as an intelligent remote ter- 
minal that is connected, through the 
modem, to a timesharing computer or 
data base. The program can be used 
with the small battery-operated 
modem directly connected to the 
HHC, in a hand-held configuration, 
or the printer and TV can be used. 

The telecomputing software can 
use an automatic X-ON/X-OFF hand- 
shaking with a host computer so that 
you can regulate the rate of display to 
your reading speed. This protocol is 
supported by most popular networks 
such as Micronet, The Source, and 
Tymnet. When a printer is not con- 
nected, you can review many lines of 
previous interaction as they appear in 
the LCD display, creating, in effect, a 
virtual printout. Incoming lines 
longer than the 26-character LCD 
display are divided only at blanks. 
This "word-wrap" feature, combined 
with the review mode, assures 



January 1981 © BYTE Publications Inc 43 



readability with the 1-line display. 

Background of the HHC 

The HHC was developed as a result 
of a unique union of Japanese and 
American technology. Friends Amis, 
with headquarters in San Francisco, 
contributed the best of Silicon 
Valley — a software-based systems ar- 
chitecture, circuit design, a unique 
operating system and SNAP lan- 
guage. The company's founders, who 
came from Atari Inc, were responsi- 
ble for introducing the now widely 
accepted consumer video games. 
Friends Amis' first product was the 
highly successful language translator 
sold by Craig, Quasar, and 
Panasonic; this product was quickly 
followed by its point of information 
display computer and the HHC 
(hand-held computer). 

Matsushita, the parent company of 
Panasonic and Quasar, in Osaka, 
Japan, brought its unparalleled 
techniques of miniaturization, in- 
dustrial design, quality assurance, 
and the ultimate in highly 



The HHC, through the 
color television Inter- 
face, can display 16 
lines of 32 characters 
each. 

automated, high-volume, low-cost 
manufacturing — areas in which Japan 
has clearly outstripped the US in re- 
cent years. Putting the best of both 
worlds together has resulted in a 
special product that could not have 
been produced alone: the first hand- 
held computer with bus architecture, 
a powerful operating system, and a 
fast 8-bit microprocessor. 

Conclusions 

•The Quasar and Panasonic HHCs 
are certainly impressive first entries 
into the new market of hand-held, 
consumer-oriented computers. Great 
emphasis has been placed on human 
engineering. This is important for any 
device marketed to the general 



public, even more so when so many 
functions are being placed into such a 
small package. 

•The HHC was designed as a basic 
unit augmented by an extensive com- 
plement of peripherals. This "de- 
bundled" approach allows you to buy 
only those peripherals you want, giv- 
ing you a customized computer at 
minimal cost. 

• Several innovations in the HHC 
computer allow it to have the power 
of conventional personal computers 
while retaining the portability of a 
hand-held unit. The use of data com- 
pression techniques and program cap- 
sules enables very large amounts of 
data to be contained within the hand- 
held unit. 

•The HHC is supplied with internal 
application programs that include a 
clock, an electronic secretary that 
reminds you of future appointments, 
and a file system for user data con- 
tained completely within the pro- 
grammable memory of the computer. 
These are nice touches that add to the 
utility of the computer. 



A Fictional Hand-Held 
Computer 

Duncan's Minisec had been a 
parting gift from Colin, and he was 
not completely familiar with its 
controls. There had been nothing 
really wrong with his old unit, and 
he had left it behind with some 
regret; but the casing had become 
stained and battle-scarred, and he 
had to agree that it was not elegant 
enough for Earth. 

The 'Sec was the standard size of 
all such units, determined by what 
could fit comfortably in the nor- 
mal human hand. At a quick 
glance, it did not differ greatly 
from one of the small electronic 
calculators that had started coming 
into general use in the late twen- 
tieth century. It was, however, 
infinitely more versatile, and 
Duncan could not imagine how life 
would be possible without it. 

Because of the finite size of 
clumsy human fingers, it had no 
more controls than its ancestors of 
three centuries earlier. There were 
fifty neat little studs; each, how- 
ever, had a virtually unlimited 
number of functions, according to 
the mode of operation — for the 



character visible on each stud 
changed according to the mode. 
Thus on ALPHANUMERIC, 
twenty-six of the studs bore the 
letters of the alphabet, while ten 
showed the digits zero to nine. On 
MATH, the letters disappeared 
from the alphabetical studs and 
were replaced by X, +, +, — , =, 
and all the standard mathematical 
functions. 

Another mode was DICTION- 
ARY. The 'Sec stored over a hun- 
dred thousand words, whose 
three-line definitions could be 
displayed on the bright little 
screen, steadily rolling over page 
by page if desired. CLOCK and 
CALENDAR also used the screen 
for display, but for dealing with 
vast amounts of information it was 
desirable to link the 'Sec to the 
much larger screen of a standard 
Comsole. This could be done 
through the unit's optical inter- 
face — a tiny Transmit-Receive 
bull's-eye operating in the near 
ultraviolet. As long as this lens was 
in visual range of the correspond- 
ing sensor on a Comsole, the two 
units could happily exchange in- 
formation at the rate of megabits 



per second. Thus when the 'See's 
own internal memory was satu- 
rated, its contents could be 
dumped into a larger store for per- 
manent keeping; or conversely, it 
could be loaded up through the op- 
tical link with any special data re- 
quired for a particular job. 



From Imperial Earth, copyright 

1976 by Arthur C Clarke. 

Reprinted by permission of 

Harcourt Brace Jovanovich Inc. 

[Editor's Note: The 'Duncan' refer- 
red to in the first paragraph is 
Duncan Makenzie, the main char- 
acter in Clarke's Imperial Earth. 
Duncan's boyhood friend is Karl 
Helmer, a character whose name is 
a variant spelling on that of our 
Founding Editor, Carl Helmers. 
For a humorous (and somewhat 
eerie) commentary on the name 
similarity and the anticipated 
possibility of a hand-held com- 
puter, see Carl Helmers' editorial 
in the April 1977 BYTE (page 6). 
"How I Was Born 300 Years Ahead 
of My Time. "] 



44 January 1981 © BYTE Publications Inc 



• The HHC retains the contents of 
memory even when it is turned off. In 
addition, you do not lose what you 
are working on if you accidentally hit 
the OFF button. These are important 
features that indicate the amount and 
depth of human engineering that has 
been applied to the design of the 
HHC. 



• The HHC will be marketed 
aggressively by both Quasar and 
Panasonic. The public reaction to this 
device, which is the first of its kind to 
be marketed on such a large scale, 
will be carefully observed by manu- 
facturers and may determine the ex- 
tent and direction of future consumer 
products in this area. We feel that the 



Panasonic/Quasar HHC is highly 
qualified to receive this scrutiny and 
that the public response will be 
favorable. ■ 



Acknowledgment 

The cover photograph and all interior 
photographs are by Ed Crabtree. Photo 2 is 
courtesy Quasar Electronics Company. 



Another Pocket Computer 

The internal architecture of the 
TRS-80 Pocket Computer is radi- 
cally different from the other 
pocket computers now reaching 
the market. Instead of a single 8-bit 
microprocessor (such as that used 
in the Quasar/ Panasonic HHC and 
the Sinclair ZX-80), the designers 
of the TRS-80 Pocket Computer 
(Sharp Electronics of Japan) decid- 
ed to use two 4-bit micro- 
processors in a unique serial con- 
figuration. 

Both microprocessors are 
custom CMOS (complementary 
metal-oxide semiconductor) in- 
tegrated circuits with built-in 
ROM (read-only memory). The 
purpose of microprocessor 1 is to 
arrange data and make decisions. 
It reads the data that is keyed in or 
fetched from programmable 
memory. It is also responsible for 
parsing arithmetic operations and 
interpreting the syntax of BASIC 
statements. It then arranges the 
data and provides instruction 
codes to microprocessor 2 through 
a transfer buffer. The actual execu- 
tion of an instruction is performed 
by microprocessor 2, which also 
updates the display and notifies 
microprocessor 1 that it has finish- 
ed its function. The respective 
duties of the microprocessors are 
listed at right. 
Memory Organization 

The programmable memory of 
the TRS-80 Pocket Computer is 
contained in four integrated cir- 
cuits. There are three memory ICs, 
each containing 512 bytes of pro- 
grammable memory. The three ICs 
which drive the liquid-crystal dis- 
play each contain 128 bytes of pro- 
grammable memory. Putting it all 
together, you end up with 1920 
bytes of programmable memory. 
After you subtract memory space 
used for the transfer buffer, input 
buffer, display buffer, fixed mem- 




Microprocessor 1 


Microprocessor 2 


Key input routine 
Acknowledgment of the 


Display processing routine 
Input buffer 
Computational result 


remaining program 


Error 


One instruction to one 


Arithmetic routine 


program step incorporation 


Character generator 


Interpreter: 

Program execute statement 


Cassette routine 


Cassette control statement 
Command statement 


Print routine 


Printer control (reserved) 


Buzzer 


Execution of manual 


Recognition of printer 


operation 


(reserved) 


Power shut-off control 


Power off 


Clock stop control 


Clock stop 



ories, and reserved keys, you end 
up with 1424 bytes of user-address- 
able memory. Into this space you 



can easily fit a BASIC program of 
around 250 lines (average 
length)... SMm 



January 1981 © BYTE Publications Inc 45 



Hereto the best 



S5ZS: 



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Multimeters. 

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Series D Handheld Models. 

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If your dealer doesn't carry Series D Multimeters 
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who does. 1-800-426-9182 



D 804: A powerful, versatile handheld 
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basic dc accuracy and more. Direct 
temperature readings in °C with K-type 
thermocouples; peak hold on voltage and 
current functions; even an audible indicator 
for instant continuity and logic level 
detection. Available January 1981. $229.* 

Series D Bench/Portables. 

D 810: By means of a Fluke-built hybrid 
converter, this multi-purpose DMM delivers 
True RMS measurements of ac voltage and 
current with speed and precision. Also 
features conductance, 0.1% basic dc accuracy, 
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Series D Accessories. 

A wide range of accessories to extend 
the measurement capabilities of your 
Series D Multimeter is available, including 
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Ifl^S] 



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* suggested U.S. list price. 

For technical data circle no, 

Circle 24 on inquiry card. 



FLUK 



Ciarcia's Circuit Cellar 



Electromagnetic Interference 



Steve Garcia 

POB 582 

Glastonbury CT 06033 



You may have noticed that certain 
household appliances such as a 
microwave oven or tools such as a 
power saw affect television reception 



Copyright © 1 98 1 by Steven A Ciarcia. 
All rights reserved. 



when they are running. This televi- 
sion interference, or TVI, is caused by 
the electromagnetic energy which is 
radiated when these electrical devices 
are in use. The general term used to 
describe such noise is EMI (elec- 
tromagnetic interference). 
EMI emanates from both natural 



and artificial sources. Natural ter- 
restrial EMI sources include lightning 
discharges, precipitation, and storms. 
Man-made EMI can come from 
electrical-power systems, rotating 
electrical machinery, gaseous- 
discharge systems, and electronic 
equipment such as radar, computers, 




Photo la: To illustrate the effects of radiated and coupled interference, a portable TV set is placed next to an operating TRS-80 Model 
I computer. The result is a very snowy picture, primarily the result of radiated noise. Also note a slight blurring of the characters on 
the TRS-80 display screen. A beat frequency caused by magnetic coupling between the two video displays causes the TRS-80 screen 
image to shake. In a longer exposure, the characters would be illegible. 



48 January 1981 © BYTE Publications Inc 



and television transmitters. Natural 
EMI is usually beyond man's control, 
and attempts to reduce it must be 
centered on the susceptible equip- 
ment. Man-made EMI, on the other 
hand, can be suppressed at the 
source — this is the most satisfactory 
way to eliminate interference. 

Various forms of EMI are a major 
concern today due to the rapid 
growth of digital electronic process- 
ing in business, industrial, and home 
environments. My mail has been 
overflowing with questions on 
computer-related interference. The 
letters have been almost evenly divid- 
ed between readers who require help 
in cutting down the EMI emitted from 
their computers and those concerned 
with their computers' own suscep- 
tibility to noise. 

The problem has received con- 
siderable news coverage lately, due to 
the FCC's (Federal Communications 
Commission's) stepping in to regulate 
noise emissions from personal com- 



The relative effect of 

capacftfve coupling of 

noise Is dependent 

upon the distance 

between conductors. 



puters and other electronic equip- 
ment. In the past, only equipment in- 
tended for certain military applica- 
tions had to meet EMI limitations. 
The few EMI filters that were in- 
stalled were primarily intended to 
protect the equipment in which the 
filters resided from the effects of EMI 
generated by external sources, enter- 
ing through the AC (alternating cur- 
rent) power lines. 

Little if any thought was given to 
attenuating electrical noise which was 
generated within the equipment, leak- 



ing out through a variety of coupling 
paths. Because of the large volume of 
complaints about EMI that have 
reached the FCC, the Commission 
has set new regulations on the max- 
imum level of electrical noise that can 
be emitted from electronic equip- 
ment. These regulations took effect 
on January 1, 1981. (See "FCC 
Regulation of Personal- and Home- 
Computing Devices" by Terry G 
Mahn, September 1980 BYTE, page 
180.) 

But what about the equipment you 
own now? What if you have an im- 
mediate noise problem? Where do 
you start to solve the problem? How 
do you detect where the noise is com- 
ing from7 How do you break the path 
between the noise source and the af- 
fected receiver? Should you put noise 
filters on every electrical outlet in the 
house? How does shielding work? 

Answering all these questions 
could easily fill a book. However, 
because EMI is such a pressing prob- 




Photo lb: Demonstration of the effects of shielding. We have added a line filter to eliminate conductive interference to the setup of 
photo la. In addition, two grounded copper sheets, one under the portable TV set and one to the left of it against the side of the 
TRS-80 video monitor, protect the TV set from radiated noise. The results can be seen as greatly improved picture quality. 



January 1981 © BYTE Publications Inc. 49 




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That's why our line of desks, stands, and enclosures also fea- 
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Gardena, CA 90249 

(213) 327-7710 



The three forms of 
noise coupling are con- 
ductive, common- 
impedance, and 
radiated-field coupling. 



lem for many computer owners, I 
think it needs to be addressed 
nonetheless. 

This article is intended as an in- 
troduction. While not endeavoring to 
cover all sources and solutions, it will 
outline the common causes and paths 
of noise and suggest possible methods 
for controlling interference. For that 
reason, I am not limiting the discus- 
sion merely to computer-generated 
EMI and related suppression 
methods. I hope the result will be a 
better understanding of the entire 
problem. 

First, a few definitions: 

• Noise: any electrical signal present 
in a circuit other than the desired 
signal. 

• Noise Path: the coupling medium 
that conducts the noise from the 
source to the receiver. 

• Interference: the undesirable effect 
of noise. 

• Susceptibility: the capability of a 
device or circuit to respond to un- 
wanted electrical noise. 

• Receiver: any circuit or device be- 
ing affected by interference. 

If you own a typical computer pur- 
chased before the FCC regulations 
went into effect, then you no doubt 
have noticed that it emits con- 
siderable EMI. Depending upon the 
manufacturer and configuration of 
the system, the extent of the noise 
may range from a little extra fuzziness 
in television pictures to an actual 
blackout of TV reception. The effect 
upon nearby television sets is depen- 
dent upon the level of the emitted 
noise, the susceptibility of the 
receiver, and the coupling channel 
which conducts the noise from the 
source to the receiver. 

Noise Coupling 

In order for noise to be a problem, 
there must be a noise source, a re- 
ceiver that is susceptible to the noise, 
and a coupling channel that transmits 
the noise to the receiver. The relation- 
ship is shown in figure la. 

We start to analyze a noise prob- 



50 January 1981 © BYTE Publications Inc 



Circle 25 on inquiry card. 



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t Apple is a trademark of Apple Computer Inc. 

tTRS-80 is a trademark of Radio Shack, a division of Tandy Corp. 



lem by defining what the noise source 
is, what the receiver is, and how the 
source and receiver are coupled 
together. It follows that there are 
three ways to break the path: 

1. The noise can be suppressed at the 
source. 

2. The receiver can be made insen- 
sitive to the noise. 



3. The amount of energy leaking 
through the coupling channel can be 
minimized. 

There are three forms of noise 
coupling: conductive, common- 
impedance, and radiated-field cou- 
pling. Figure lb demonstrates a 
typical situation. In this circuit, the 
commutator noise generated from the 




Photo 2: The simplest method of noise reduction is to use capacitors as simple filters. 
This photo shows two 0.1 fiF, 1000 V capacitors used to filter the AC power line in a 
video terminal. 




motor is both conducted along and 
radiated from the leads going to the 
motor-control circuit. Also, the 
motor control and the television 
receiving set are plugged into the 
same long extension cord, so they 
share a common line impedance. The 
coupling channel consists of: 

• conduction on the motor power- 
supply leads 

• radiation from the leads 

• common line impedance 

To eliminate the motor's influence on 
the TV, all three parts of the coupling 
path must be broken. You can apply 
EMI controls to any or all of these 
elements. 

Conductive Coupling 

Conductively coupled noise is 
often overlooked. A wire passing 
through a noisy environment picks 
up noise either by capacitive or 
magnetic coupling and conducts it to 
another circuit. A simple representa- 
tion of capacitive coupling between 
two conductors is shown in figure 2. 
When the resistance from conductor 2 
to ground, R, is large, the voltage 
coupled from conductor 1 to conduc- 
tor 2 is defined as follows: 



V N = 



\ c a + C 2C J 



v, 



Photo 3: Commercial power-line filters from Corcom Inc, 2635 North Kildare Ave, 
Chicago IL 60639. Prices range from $10 to $20. 



where C 12 is the stray capacitance bet- 
ween conductors 1 and 2, C iC is the 
capacitance between conductor 1 and 
ground, C 2C is the capacitance be- 
tween conductor 2 and ground, R is 
the resistance from conductor 2 to 
ground, V, is the interfering voltage, 
and Vat is the noise voltage produced 
on conductor 2. 

Even though this may appear small 
(perhaps a few microvolts), 
remember that some receivers 
amplify input signals thousands of 
times. A few microvolts of noise on 
the antenna terminals of a television 
set could easily be greater than the 
desired video signal. 

Figure 3 shows the effect of conduc- 
tor spacing on capacitive coupling. 
The coupling factor is said to be dB 
(decibels) when the two conductors 
are separated by a distance equal to 
three times the conductor diameter 
(for 22-gauge wire, d = 0.71 mm or 
about 0.028 inches); the factor 
decreases rapidly as the spacing in- 
creases. Separating wires reduces the 
capacitive coupling between them. 
However, little is gained by spacing 



52 January 1981 © BYTE Publications Inc 




At $7951 how tough can 
these new Tigers be? 



Introducing the new Paper Tiger™ 
445 with the most rugged printing 
mechanism ever put in a low-cost 
matrix printer. 

The 445 comes with a reliable ballis- 
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And the new 445 gives you the per- 
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'Suggested U.S. retail price. 
**Apple is a trademark of Apple Computer Inc. 
"TRS-80 is a trademark of Radio Shack, a division of Tandy Corp. 



NOISE 
SOURCE 




COUPLING 
CHANNEL 




RECEIVER 







Figure la: The general case of the transmission of electrical noise. 



AC POWER LINE 




(TELEVISION SET) 



Figure lb: A typical noise-coupling situation: commutator noise generated by the motor 
is conducted along and radiated from the connecting leads. Common line impedance 
shared by the receiver (a television set) and the motor cause motor noise to be imposed 
on the receiver's power input. 



Ct2=stray capacitance between 

conductors 1 and 2 
C ic = capacitance between conductor 

1 and ground 

Cic — capacitance between conductor 

2 and ground 

R = resistance from conductor 2 to 

ground 
Vi ^interfering voltage 
V N =noise voltage produced on 

conductor 2. 



CONDUCTORS 




Figure 2: Representation of capacitive coupling between two conductors. The defini- 
tions of the symbols are listed above. 



1/8 1/4 1/2 



SEPARATION D FOR 22-GAUGE WIRE (INCHES) 
1 11/2 2 2 1/2 3 



-2 
-4 
-6 
-8 
-10 
-12 


























































































Figure 3: The relative effect of capacitive coupling of noise is dependent upon the 
distance between conductors. In the chart shown, for 22-gauge wire, coupling is signifi- 
cant only when the conductors are closer together than 25 mm (1 inch). 



the conductors more than 40 
diameters apart (about 25 mm or 1 
inch). 

Magnetic Coupling 

Magnetic coupling is also a prob- 
lem. When a current flows in a closed 
circuit, it produces a magnetic flux 
which is proportional to the current. 
If two wires are parallel, the flux pro- 
duced in one wire will induce a 
voltage in the second wire. This in- 
duced voltage constitutes noise. 
When you are running wires between 
sensitive electronic components, 
avoid laying signal wires parallel to 
noisy, high-current AC power lines. 
If a signal line must cross a power 
line, have it do so at a right angle. 

Common-Impedance Coupling 

Common-impedance coupling oc- 
curs when currents from two different 
circuits flow through a common im- 
pedance. Two examples of this type 
of coupling are shown in figures 4 and 
5. In figure 4, the ground currents of 
both circuits flow through a common 
ground impedance. The ground 
potential of circuit 1 is modulated by 
circuit 2, and vice versa. Any fluctua- 
tions in the ground current of circuit 2 
will be coupled through the ground 
impedance, X c , to circuit 1. 

Another example is the power- 
distribution schematic diagram 
shown in figure 5. Any change in the 
current required by circuit 2 will af- 
fect the voltage at the terminals of cir- 
cuit 1. This effect is due to the com- 
mon impedance of the power-supply 
lines and internal source impedance, 
R Sl of the power supply. Shorter 
leads will help reduce the line im- 
pedance, but the source impedance 
always remains. The typical com- 
puter system plagued with common- 
impedance noise is one where the 
builder has attempted to use the pro- 
cessor power supply to run 
everything, including peripherals. 
The apparent economy is outweighed 
by periodic system crashes and un- 
predictable errors. 

Radiated-Field Coupling 

Radiated electric and magnetic 
fields provide the last form of cou- 
pling. This form of coupling can be 
most easily thought of as free-air 
radio transmission. The interfering 
circuit broadcasts noise just like a 
radio station, and every conductive 
surface in the receiver acts as an 
antenna. At close distances, the noise 
can in fact be much stronger than a 
real radio station. [Many readers 



54 January 1981 © BYTE Publications Inc 




University Basic ROM kit. 
Nowavailable for TM990/189 module. 

On-board. Or off. 



We've added another option to our 
TM990/189 University Module. Now, in 
addition to the I/O and RAM expansion 
kits previously offered, you can buy the 
TM990/189-1 module with a University 
Basic ROM kit on-board, and get new 
hardware features, too. Features like: 

• 1Kbyte of extra RAM 

• Asynchronous communication port 

• Off-board CRU expansion 

All for the attractive price of $399*. 

With the TM990/469 Basic ROM kit, 
standard 189 modules provide "hands- 
on" training for students and engineers 
who want to learn a high-level language 
like Power Basic. The kit also supports 
a subset of the Power Basic commands 
and statements including SAVE and 
LOAD. Unique color commands such as 
TONE, COLOR, PATTERN and 
SPRITE work with TI's TMS9918 
Video Display Processor. Another fea- 
ture is the ability to access assembly 



language routines from the University 
Basic programs. 

When purchased separately, the 
ROM kit costs only $110*. 

Of course, the standard TM990/189 is 
still available. And, it's still your best 
ticket into the microprocessor world. 
For maximum hands-on experience. 
For ease and simplicity of learning and 
teaching about microprocessors, hard- 
ware, and assembly language. 

Outstanding features for the stan- 
dard fully assembled TM990/189 stand- 
alone learning tool include: 

• Powerful 16-bit microprocessor with 
minicomputer instruction set. 

• 45-key alphanumeric keyboard and 
10-digit, 7-segment display for easy 
assembly language programming. 

• ROM-resident software 

• Audio cassette interface 

• Easy-to-add EIA and TTY interface 

• IK byte RAM expandable to 2K 



• 4K byte ROM and 2K byte expansion 
EPROM socket. 

• 16-bit programmable I/O controller. 

• User addressable LEDs and sound 
indicator. 

A 570-page tutorial text accompa- 
nies the TM990/189. It's a detailed 
guide for self-paced learning. Or, the 
basis for a three-hour university 
course. Also with the module: a 300- 
page user's guide. 

The TM990/189 complete with tuto- 
rial text and user's guide is only $299*. 

Order your University Module from 
your nearest authorized Texas Instru- 
ments distributor. For more informa- 
tion, send for a free copy of our newly 
revised brochure, CL- i — I o 
423B. Write to Texas In- I JnC 
struments Incorporated, ^"^ h[]f 
P.O. Box 1443, M/S 6404, 
Houston, Texas 77001. 




*U.S. price, subject to change without notice. 
© 1980 Texas Instruments Incorporated 

Circle 28 on inquiry card. 



Texas Instruments 



INCORPORATED 



CIRCUIT 1 



CIRCUIT 2 



GROUND VOLTAGE 
OF CIRCUIT 1 



I 
I 

A? 



GROUND CURRENT 
l2G 



/77 



"GROUND CURRENT 
llG 



COMMON GROUND 
IMPEDANCE 



GROUND VOLTAGE 
OF CIRCUIT 2 



fh 



Figure 4: Common-ground-impedance coupling is caused by two pieces of equipment using the same electrical lead to ground. The 
ground current of one influences the ground-reference voltage of the other, and vice versa. One solution to this is a single-point 
grounding system. 



probably know of methods for 
generating computer music by using 
an AM radio to pick up computer- 
emitted noise while the appropriate 
program runs... RSS] 

The characteristics of a field are 
determined by the source of the field 
and the distance between the source 
and the point of observation. When 
the receiver is near-field, closer than 
1 / 6 wavelength, the electric and 
magnetic fields are considered 
separately. Any source/receiver 
distance greater than V 6 wavelength 
is far-field, and the electric and 
magnetic fields are considered 
together and are called simply the 
electromagnetic field. 

At frequencies below 1 MHz, most 
coupling is near-field, because the 
near-field boundary at the corre- 
sponding wavelengths extends out to 
approximately 45 meters (150 feet) or 
more. At 100 MHz, most coupling is 
far-field. For purposes of this discus- 



sion, however, radiated-field- 
interference problems within any 
given piece of equipment should be 
considered to be caused by near-field 
radiation unless the interference is 
clearly from far-field radiation. 

Finding and Fixing 
a Noise Problem 

The key to solving a noise problem 
is finding the source of the noise. In 
fact, your computer might not be the 
culprit. More than one computer 
owner has suffered complaints about 
his "computerized noise generator" 
only to later find that the real source 
of the interference was the solid-state 
light dimmer on the overhead light. 

Continuous sources of noise are 
easier to identify than intermittent 
ones. The interference from ap- 
pliances and computers is usually 
broadband, affecting the entire radio- 
frequency spectrum. Digital 
waveforms are especially rich in har- 





_ — SOURCE IMPEDANCE 
'l + l2 


^i_^ 




*s 




, . - 


CIRCUIT1 


<T 


COMMON LINE 
IMPEDANCES 






POWER 
SOURCE 






^2 










CIRCUIT 2 















Figure 5: Common-power-source coupling occurs within a computer that uses a single 
power supply for multiple peripheral devices. Due to the impedances on the connecting 
lines, the current drawn by one circuit changes the voltage "seen" by another circuit. 



monic frequencies, as shown in figure 
6. Therefore, the continuous, 
harmonic-rich emissions of com- 
puters are relatively easy to find. 

A standard battery-operated AM 
radio makes a good EMl detector. 
With it tuned to a frequency at which 
the noise is the loudest, just roam 
around the house looking for the 
place where the interference is the 
strongest. 

If you suspect the computer, then 
move the radio around it and along 
the connecting cables. You will be 
surprised how much the cables con- 
tribute to radiated noise. Disconnect 
cables and peripheral devices selec- 
tively to further isolate interference 
sources. Often, the long leads be- 
tween the computer and printer emit 
electromagnetic radiation as well as 
any transmitting antenna you could 
have possibly designed. 

Finally, move the radio along the 
power cord you have supplying the 
computer system. If you are using a 
15-meter (50-foot) extension cord 
without the ground lead connected, 
shortening the cord will reduce radia- 
tion considerably. 

If the computer system is indeed 
found to be the source of the in- 
terference, there are a variety of 
possible coupling paths. The coupling 
efficiency of digital interference is 
proportional to frequency; the higher 
the frequency, the greater the in- 
terference. Depending upon the 
design, these interfering signals can 
radiate from the source, couple from 
line to line, or be conducted directly 
through connecting wires to the exter- 
nal environment. Each noise path 
must be suppressed. 

Grounding 

Grounding is the primary way to 



56 January 1981 © BYTE Publications Inc 



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The three ASCII compatible interfaces (parallel, 
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minimize unwanted noise and 
pickup. It is often the optimal solu- 
tion to most problems. There are two 
basic objectives in designing proper 
grounding systems. The first is to 
minimize the noise voltage generated 
by currents from two or more circuits 
flowing through a common ground 



impedance; the second is to avoid 
creating ground loops which are 
susceptible to magnetic fields and dif- 
ferences in ground potential. This 
ground is the reference point for all 
voltages in the system. 

Signal grounds are generally 
classified as either single-point or 




Photo 4: Switching-type power supplies, which use high-frequency pulse-width- 
modulated waveforms, are a potential source of noise. Most often they are contained in 
shielded enclosures, as in the Apple II, to eliminate possibly interfering radiation. 




Photo 5: The Atari 400 and Atari 800 personal computers are designed to eliminate any 
forms of EMI coupling and to meet the new FCC standards. This requires considerable 
shielding. The high-frequency processor and memory sections of the printed-circuit 
board are segregated from the power supply and I/O (input/ output) areas. A heavy- 
gauge aluminum enclosure encircles the high-frequency sections, as shown in this Atari 
800. 



58 January 1981 © BYTE Publications Inc 



The Talk of the '80s 



^777/yjJ^nmtkk ..,,,*,.. 




SoftCare. 



A New Medical Billing System That is Easy, and Works! 



FILL IN THE BLANKS 

The only system that works like you do. Add, change, 
or delete material right on the form (displayed on the 
video screen). It's really easier than filling in the blank 
because you can go back and type over any mistake 
you make. 

NO BATCHING 

As the information is entered, the system automatic- 
ally detects clerical errors in patient information, pro- 
cedure codes, and procedural data. No waiting days 
or weeks for verification. 



INSTANT ACCESS 

Up to date patient information available anytime. 
Patient files are updated everytime a transaction is 
entered. All you need to check their files is to enter 
the patient's name — no ID number. 

PRIVATE AND THIRD PARTY BILLING 

System keeps track of third party billing and insur- 
ance claims. You can bill the patient on paper while 
they are in the office! Resubmission of a claim is as 
simple as pushing a button. 



TECHNICAL SPECIFICATIONS 

Written in Pascal, the system runs on most any 56K or 64K micro or mini computer. The system is currently operating 
on Dynabyte, Cromemco, Onyx, Vector Graphic, and Digital Equipment Corporation (DEC) computers. Different 
systems provide 500 to 10,000+ patient capacity. 



Contact your Local computer store or 




Circle 31 on inquiry card. 



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SOFTWARE 

119 Fremont Street, San Francisco, CA 94105, (415) 546-1596 



multipoint grounds. From a noise- 
reduction point of view, the single- 
point ground is more desirable. Nor- 
mally, with equipment operating at 
frequencies below 1 MHz, a single- 
point system is used. Above 10 MHz, 
a multipoint ground is best, to 
minimize ground impedance. Be- 
tween these bounds, the type of 
grounding depends on the system 
configuration and layout. For per- 
sonal computers, single-point 
grounding is advised. 

The AC power ground is of little 
practical value as a signal ground. It 
is usually connected to signal ground 
as a safety measure only. 

Shielding 

When properly used, shielding is 
an effective means of reducing the 
coupling of noise between conduc- 
tors. Shields consist of a variety of 
conductive materials (usually steel, 
copper, or aluminum), all of which 
serve in some way to reflect, absorb, 
or otherwise channel noise currents 
away from the protected conductor. 
Shields may be placed around com- 
ponents, circuits, complete 
assemblies, cables, or transmission 
lines. 



A parallel-tuned trap 
cannot be used for 
broadband computer- 
generated noise. 



The best way to minimize radiated 
noise and susceptibility on connecting 
wires is to use coaxial cable (coax) or 
shielded twisted-pair cabling between 
peripheral devices and the processor. 
If the coaxial-cable shield is grounded 
at one end, it will protect the central 
conductor from electric-field radia- 
tion. Grounding the shield at both 
ends creates a return current in the 
shield, which generates a field that 
cancels the conductor's electric field 
and any magnetic interference as 
well. 

In twisted-pair shielded wire, 
grounding the shield at one end takes 
care of electric fields, while twisting 
the conductor with the return line 
serves to reduce magnetic suscep- 
tibility. (Twisted-pair shielded wire is 
especially useful on low-level 
signals.) The number of twists per 
foot determines the insensitivity to 



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magnetic fields. 

When comparing coaxial cable and 
shielded twisted-pair cable, it is im- 
portant to recognize their differences 
in signal propagation, irrespective of 
their shielding characteristics. Shield- 
ed twisted-pair cable is very useful at 
frequencies below 100 kHz. Above 1 
MHz the signal losses are con- 
siderable. 

Coaxial cable, grounded at one 
end, provides a good degree of pro- 
tection from capacitive pickup and 
can be used at all frequencies from 
DC (direct current) to UHF (ultra- 
high frequencies). However, due to 
the potential for noise currents to 
flow through the shield (which is also 
part of the signal path), coaxial cable 
is better used at higher frequencies 
where such errors are minimized. 
Shielded twisted-pair cable, on the 
other hand, does not exhibit this 
problem and should be used for con- 
ducting low-frequency signals. 

An unshielded twisted pair, unless 
it is balanced, provides very little 
protection from capacitive pickup, 
but can still be good for magnetic- 
field protection. Plain untwisted-pair 
cable, such as the zip cord you might 
purchase from a hardware store, pro- 
vides no electromagnetic-field protec- 
tion and should be avoided if you 
have a noise problem. 

Multiple-conductor cables, in- 
cluding ribbon cables, are also 
available in twisted-pair configura- 
tions. A common cable used in data 
acquisition is a twelve-conductor 
shielded cable that consists of six 
twisted pairs surrounded by a single 
foil or braided shield. This cable is 
very expensive, however, and it is 
best acquired on the surplus market. 

Shielding the connecting cables 
may eliminate only part of the prob- 
lem, especially if you determine that 
the major source of radiation is the 
computer. Most computers are en- 
cased in metal chassis. If these are not 
properly grounded, the benefits of the 
metal as shielding material are lost. 

On the other hand, if the computer 
is encased in plastic, the only solution 
is to coat the inside (or the outside) of 
the case with a conductive substance 
and connect it to signal ground. 
Aluminum foil, for example, could be 
used, but I suggest that you try all the 
other suppression measures before at- 
tempting this. 

Encasing the entire computer in a 
conductive enclosure is not un- 
thinkable. In fact, newer small com- 
puters such as the Atari 800 and 
Hewlett-Packard HP-85 are built ex- 



60 January 1981 © BYTE Publications Inc 



Circle 32 on inquiry card. 



Circle 33 on inquiry card. 



When It Comes 
To Add-on Memory... 



LOBO 
Has It All. 



LOBO DRIVES manufactures a full line of S-1 00 

computer compatible disk drives. All drives are 

software compatible with most S-1 00 disk operating 

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fixed disk drives, and several Floppy/Fixed disk 

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• Single/Double Density 

• Soft Sector Format 

• Complete Software Compatibility 



MODEL 800/850 DUAL FLOPPY 
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LOBO DRIVES offers you a choice of 
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• Compatible with Most S-1 00 DOS 
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Telex: 658 482 



Circle 34 on inquiry card. 

PERSONAL 

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62 January 1981 © BYTE Publications tnc 



actly that way. It is very effective in 
both containing the computer's elec- 
tromagnetic fields and protecting the 
computer circuitry from external 
noise. When an EMI field impinges on 
a shield, some of its energy is 
reflected at the first surface, some is 
absorbed by the shield material, some 
is reflected by the second surface, and 
some passes through. In general the 



following is true of enclosure-type 
shielding: 

• Magnetic fields are harder to shield 
against than electric fields. Magnetic 
material should be used to shield 
against low-frequency magnetic 
fields. 

• At high frequencies, a good conduc- 
tor suitably shields against both elec- 



Summary of Noise-Reduction Techniques 


Suppressing noise at the source: 


4. Keep ground leads as short as 




possible. 


1. Enclose noisy sources in a 


5. Separate noisy and quiet leads. 


shielded enclosure. 


6. Use a single-point grounding 


2. Filter all leads leaving a noisy 


system. 


environment. 


7. Avoid ground loops. 


3. Shield and twist noisy leads. 


8. Keep sensitive-signal leads as 


4. Ground both ends of coaxial- 


short as possible. 


cable shields to suppress radiated 




interference. 


Reducing noise at the receiver: 


5. Limit pulse-rise times where 




possible. 


1. Use frequency-selective filters 




where applicable. 


Eliminating noise coupling: 


2. Use shielded enclosures for sen- 




sitive circuitry. 


1. Twist and shield signal leads. 


3. Provide proper power-supply 


2. Ground shielded leads used to 


filtering. 


protect low-level signals at one end 


4. Separate signal and hardware 


only. 


grounds. 


3. Avoid ground leads in common 


5. Use shielded cables to protect 


between high-level and low-level 


low-level signals. 


equipment. 






Photo 6: The underside of an Atari 800. Metal plates enclose the processor and 
memory. The green printed-circuit board on the lower left contains the keyboard cir- 
cuit. Since it runs at low frequencies, it does not require a shielded enclosure. 

Circle 35 on inquiry card. — ► 



NOW CLEANING YOUR OWN 

DISKETTE HEADS COULD SAVE 

YOU A $ 40 SERVICE CALL. 

AND A LOT MORE. 



The recording heads on your 
diskette drives may be dirty — 
and that can cause you a lot of 
grief. There's the serviceman 
you have to call when the 
machine doesn't perform. (You 
know how much service calls 
cost these days!) There's 
machine down-time. Idle data 
entry clerks. All the other delays 
a cranky machine can cause. 
And that service call might 
not even be necessary. 

3M solves the problem 
in seconds-and leaves 

your heads 
"Computer Room Clean'! 

The Scotch* head-cleaning 
diskette kit lets you clean the 
read-write heads on your 
8" or 5 1 /4" diskette drives. In just 
30 seconds, without any 
disassembly, mess or bother, 
the heads can be completely 
cleansed of dirt, dust, magnetic 
oxides-all the things that can 
get into your machines every 
day. And foul them up. 

Just saturate the special 
white cleaning pad in its jacket 
with the cleaning solution. Then 
insert the jacket into the disk- 
ette drive and turn it on. Your 
machine does the rest. The 




heads are microscopically cleaned 
without wear, without abrasion. 

This 3M head-cleaning 
diskette kit has been evaluated 
and approved by major diskette 
drive manufacturers. It's the 
best possible way to clean your 
heads without service calls or 
machine teardowns. 



At only $1 per cleaning- 
it's the best insurance you 
can get. 

This fast-cleaning new Scotch 
kit comes with everything 
you need (including special 
fluid, applicator tip, cleaning 
diskettes) to handle up to 
30 cleanings. That's only about 
a dollar a cleaning. 

With the Scotch head-clean- 
ing diskette kit, you could save 
yourself a lot more than just a 
service call. So try this remark- 
able kit today. For the name of 




J 


otct 

oc 


i 

cleaning 


1 


"1 


HIV! 

is?" 

CUAJfn 




PSr ' 


1 ^ 


i 




* 


■ J 





A Scotch cleaning diskette shown 
before use, and after 15 cleanings 
of recording heads. 



the dealer nearest you, call toll 

free: 800-328-1300. 

(In Minnesota, call collect: 

612-736-9625.) Ask for the 

Data Recording Products 

Division. 





Circle 36 on inquiry card. 



CP/A 



OPTIMIZED SYSTEMS 
SOFTWARE 

PRESENTS 

CONTROL PROGRAM/APPLE 
the DOS you have been waiting for 

OSS CP/A is an all new, disk-based 
operating system which provides 
commands and utilities similar to 
CP/M". CP/A has byte and block I/O, a 
simple assembly language interface, 
and direct access via Note and Point. 
And it's easy to add your own com- 
mands or device handlers. CP/A is 
expandable, flexible, consistent, 
easy-to-use and available now with 
compatible program products: 

BASIC — Some of the features of OSS 
BASIC are syntax checking on program 
entry, true decimal arithmetic (great for 
money applications), 32K byte string sizes, 
flexible I/O, long variable names (up to 255 
significant characters), and the ability to get 
and put single bytes. 

BUSINESS BASIC WITH PRINT USING — 

This is virtually the only basic available on 
the Apple that has PRINT USING. It also 
has record I/O statements and all the 
features of our standard BASIC. 

EDITOR/ASSEMBLER/DEBUG — OSS 

EASMD is a total machine language de- 
velopment package. The editor provides 
functions like FIND, REPLACE, etc. The 
assembler uses standard 6502 mnemon- 
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memory or to a disk file. 

Prices of CP/A with: 

BASIC $ 69.95 

Business BASIC 84.95 

EASMD 69.95 

BASIC + EASMD 1 09.95 

Business BASIC + EASMD .... 124.95 
Requires 48K RAM and DISK 

Add $3.50 for shipping and handling in continental USA. 
California residents add 6%. VISA/Master Charge wel- 
come. Personal checks require two weeks to clear. 

SEE YOUR DEALER or ORDER TODAY 



OPTIMIZED SYSTEMS SOFTWARE 
Is a product of 

Shepardson Microsystems, Inc. 
20395 Pacifica Dr., Suite 108B 
Cupertino, CA 95014 ' 
(408) 257-9900 

CP/M is a registered trademark of Digital Research 



trie and magnetic fields. 

• Shielding effectiveness is increased 
with thicker shielding material. 

• In practice, actual shielding effec- 
tiveness obtained is determined by 
the leakage through seams and joints, 
not by the shielding effectiveness of 
the material. 



Filtering 

Grounding and shielding were 
prescribed to eliminate noise at the 
source. The final measure, filtering, is 
applicable either at the source or at 
the receiver. Filtering is generally the 
easiest form of noise abatement. It is 
primarily used to reduce noise con- 




Photo 7: The Atari computers allow the user to plug in special game and business pro- 
gram cartridges. These ROM packs (read-only-memory modules), which are connected 
directly to the processor bus, must also be kept within the shield when the computer is 
running. This is accomplished using a special molded, %-inch (9.5 mm)-thick socket that 
is electrically part of the shield. A plate of aluminum with conductive gasket material 
around the edges is attached to the cover. When the cover is closed, the memory is com- 
pletely shielded and virtually no electrical noise is emitted. 




Photo 8: To reduce any high-frequency harmonics that might radiate from the video- 
monitor cable, a toroidal ferrite core may be wrapped in the line. 



64 January 1981 © BYTE Publications Inc 



Circle 37 on inquiry card. 



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The ACE 64K Distributed Process- 
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(a) 



FUNDAMENTAL 

FUNDAMENTAL AND 3RD HARMONIC 

FUNDAMENTAL, 3RD, AND 5TH HARMONICS 




(b) 



4V/jr 



I , I , I 



123456 789 
HARMONICS 

Figure 6: Within the computer and be- 
tween peripherals, signals are digital. (6a) 
Such signals are square waves with very 
fast rise times, composed of the fun- 
damental frequency, u, and all the odd 
harmonics of the fundamental frequency. 
In a computer with a clock frequency of 8 
MHz, there will be radiated noise at 8 
MHz, 24 MHz, 40 MHz, etc. (6b) The 
amplitude becomes less at each higher 
harmonic. 

f(t) = l^sin wt + ^sin 3o)f + §^sin 5u>f + |^sin 7a>t + 

7r 3tt ot fw 



AC LINE 




Figure 7: A simple low-pass line filter with homemade inductors. 



-3/4 in.- 



1 



1/2 in., 12.7 mm 



10 TURNS 
NUMBER 16 WIRE 
FOR L 



duction into or out of the AC power 
lines. 

A circuit used as a power-line filter 
is a low-pass filter ideally designed to 
supress all frequencies above 60 Hz. 
Such filters are commercially 
available from many sources but are 
also easy to construct. 

If you prefer to build a simple line 
filter, figure 7 shows the schematic 
diagram of a typical circuit. This cir- 
cuit is applicable for use in instances 
of minor television interference. It 
should clear up most line-coupled 
noise problems. 

As a practical matter, simple line 
filters are less than ideal. Typical 
commercial single-section line filters 
use toroidal inductors and provide 
about 55 dB of attenuation at 3 to 5 
MHz. Attenuation can be typically 
increased to 70 dB by adding a second 



LC (inductance/capacitance) section. 
A line filter should be used on the 
computer and any susceptible 
receivers. 

If your TV reception is still garbled 
or nonexistent after you install a line 
filter, then your set is picking up 
radiated noise through the antenna 
input. Generally, you will find the 
VHF (very-high-frequency) channels 
to be affected much more than the 
UHF channels. This is because most 
of the noise energy generated by the 
computer is at frequencies below 100 
MHz (VHF channels 2 thru 6 are be- 
tween 54 and 88 MHz). At frequencies 
above 470 MHz, where channel 14 
starts, there isn't much energy in the 
noise spectrum. 

The process of eliminating 
radiated-noise pickup starts with 
replacing the 300-ohm twin-lead cable 



from the antenna to the television 
receiver with 75-ohm coaxial cable. If 
the problem persists after you do this, 
then additional filtering is in order. If 
the noise is determined to be a single 
frequency, such as that emitted from 
a Citizens' Band radio transmitter 
next door, then a parallel-tuned trap 
that singles out this one frequency 
should be used. Figure 8 shows such a 
filter circuit. 

Computer-generated noise is 
broadband rather than narrow-band. 
A parallel-tuned trap cannot be used, 
and a different filtering technique 
must be employed. A high-pass filter 
on the set's antenna input may be 
needed. The system clock frequency 
of most computers is between 1 MHz 
and 8 MHz. Harmonics will, of 
course, reach much higher frequen- 
cies. The harmonic amplitude 



66 January 1981 © BYTE Publications Inc 



Circle 38 on inquiry card. 



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Let's face it. We all have to make decisions. Decisions that can change our lives. Decisions that can 
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Figure 8: A parallel-tuned trap filter for use on FM-radio or television sets. Each LC 
combination is set for resonance at the frequency that is causing the interference. Trap 
filters are suitable only for eliminating narrow-band interference such as that from 
Citizens' Band radio transmitters. 

Here, the cen ter frequency trapped by the filter can be calculated from the equation 
fo=159.2/\JLC , where / is the resonant frequency in Hertz, L is the inductance in 
microhenrys, and C is the capacitance in microfarads. 



300 fl 

ANTENNA 



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TERMINALS 



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Figure 9a: A high-pass filter for use with 300-ohm antenna cable. A high-pass filter can 
be used on television-receiving sets and FM-radio receivers to reduce or eliminate noise 
at frequencies under 50 MHz, such as that produced by personal computers. These 
filters pass frequencies above 54 MHz (where the VHF-TV broadcast band lies) and at- 
tenuate any lower frequencies where noise may reside. 

In this design, the inductors Li and L 2 are made from eight turns of 18-gauge wire in a 
coil 19 mm (V* inch) in diameter, 25.4 mm (1 inch) long. 



diminishes with each successive fre- 
quency multiplication. 

If we can presume that practically 
all of the radiated noise is below 54 
MHz where channel 2 starts, then we 
can construct a filter that passes only 
the frequencies above 54 MHz. The 
filter should actually be set for a cut- 
off frequency of 45 MHz to reduce at- 
tenuation at the desired frequencies 
above 54 MHz. In combination with 
coaxial cable, the high-pass filter 
usually remedies 80% of all in- 
terference problems. Figure 9 shows 
the schematic diagram of a typical 
high-pass filter. 

The use of a coaxial cable, a line 
filter, and an antenna filter should get 
you out of the digital doghouse. 

In Conclusion 

EMI is but one of the many prob- 
lems confronting computer users. I 
have only touched on a few of the 
basics in this short article, with my 
concern obviously centered on the ef- 
fect the computer has on other equip- 
ment. I hope that I have provided you 
with some solutions. 

The effect the environment has on 
the computer is an entirely different 
matter. You have probably noticed 
that I have tactfully avoided discuss- 
ing things like voltage spikes, line 
fluctuations, frequency variations, 
and line interruptions. While often in- 
cluded in the consideration of EMI, 
problems of power-line performance 
is an entirely different subject, requir- 
ing different solutions. 

Noise filtering may improve your 
relations with your neighbor, and 
reduce the susceptibility of your 
equipment to transients, but it will do 
nothing to save you from the power 
company. It remains for me to cover 
this latter problem in a separate 
discussion.! 



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Figure 9b: A high-pass filter for use with 75-ohm coaxial antenna cable. In this design, 
inductors L 3 and L 3 are made from four turns of 14-gauge wire in a coil 6.35 mm (Vt 
inch) in diameter and 12. 7 mm {Vi inch) long, tapped one-half turn from the end. Induc- 
tors L s and L t are made from ten turns of 22-gauge wire in a coil 6.35 mm (V* inch) in 
diameter, with the turns spaced at 3.175 per cm (8 per inch). 



Next Month: 

Milton-Bradley s Big Trak is a 
clever toy. Wireless remote control 
makes it even more clever. 

Editor's Note: Steve often refers to 
previous Circuit Cellar articles as 
reference material for the articles he 
presents each month. These articles are 
available in reprint books from BYTE 
Books, 70 Main St, Peterborough NH 
03458. Ciarcia's Circuit Cellar covers ar- 
ticles appearing in BYTE from September 
1977 thru November 1978. Ciarcia's Cir- 
cuit Cellar, Volume II presents articles 
from December 1978 thru June 1980. 



68 January 1981 © BYTE Publications Inc 



Circle 204 on Inquiry card. 



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K TRS-80 Model III. The new standard in 
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dFEW 

OF THE FEATURES 

THdTGVETEMK 

THE EDGE 111 

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and benefits. Features such as 

Low Entry Cost The basic 
8600 color system is priced at about 
$15,000. It can be upgraded to 
higher resolution and a greater 
number of colors, but even fuJJy 
expanded it still comes in at less 
than $19,000. 

Or, you can start with a black 
and white system for less than 
$8,500 and upgrade to color at any 
time by the addition of a color 
processor and monitor. 




Simultaneous 
Graphic/Text Display 

The 8600 offers outstanding 
control and formatting of both 
graphics and text. Completely 
under user control, the multiple 
memory planes permit simul- 
taneous display and indepen- 
dent manipulation of text and 
graphics to achieve special 
effects such as overlays, scroll- 
ing and zoning. This capa- 
bility, in conjunction with 
Terak's unique flexible charac- 
ter generation, enables the 
8600 to present visual displays 
that are unequalled by any 
other system of its class. 



Broad Spectrum 
of Color Selection 

The number of color maps 
and the colors in each map is 
completely under software 
control. With a 6-plane mem- 
ory (640 x 480 x 6), up to 64 
colors can be displayed on the 
screen simultaneously. With 
a 3-plane memory (320 x 240 x 
3), up to 8 simultaneous colors 
can be displayed from any 
one of eight color maps. The 
output of the color map pro- 
duces eight levels each for red, 
blue and green. The result 
is the selection of 512 possible 
levels of intensity, saturation 
and hue. Switching from map 
to map is under software 
control. 



The 8600 monitor screen can 
be divided into a maximum of 
four variable size zones. In <i 
typical application, the upper 
three zones can display graph- 
ics while the lower zone dis- 
plays text. The text can be 
scrolled or slow scrolled while 
the graphics are changing to 
coincide with the text changes. 




Dual Processors For Speed and 
Flexibility The two 16-bit proces- 
sors (each with its own memory) 
are assigned those tasks which they 
can accomplish most efficiently and 
with the fastest throughput. The 
result is more available user space 
in memory faster processing and 
increased flexibility of operation. 

DEC Based Hardware and 
Software The DEC based hard- 
ware and software includes the 
LSI -11 main processor, RT-11 oper- 
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easily integrates peripheral devices. 

USCD Pascal, Too The 8600 
also supports the easy to use USCD 
Pascal operating system for pro- 



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Siggraph Core Standards, 2D1 
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for Fortran, Basic and Pascal. 

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ible 
Character Generation 

nlike the rigid cell sizes of 
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the 8600 character generation 
is under software control. 
Characters can be programmed 
to any size or shape including 
the creation and display of 
oreign languages such as 
Arabic, Hebrew, Russian, etc., 
mathematical symbols, primi- 
tives, specially configured 
letters, characters or symbols 
and a host of others. 



Fill Algorithms 

Terak's fill algorithms are fast 
and allows you to fill the inside 
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figures without calculating points. 
This not only helps define charts, 
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the appearance of presentation 
material. 




DYNAMIC 
FEATURES 

The 8600 also offers several 
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Smooth or Line Scrolling 

The speed of the vertical, 
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The 8600 can be synchronized 
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■ ■ , ■ 



The NEC PC-8001: A New 
Japanese Personal Computer 



Michael Keith 

D46 Abbington Dr 

Hightstown NJ 08520 

C P Kocher 

505 South 42nd St 

Philadelphia PA 19104 



One of the products attracting a lot 
of attention at the 1980 NCC (Na- 
tional Computer Conference) in Ana- 
heim, California was the PC-8001 
personal computer produced by NEC 
(Nippon Electric Company). Because 
this well-made little machine has been 
selling briskly in Japan, NEC was try- 
ing to gauge consumer reactions to 
the PC-8001 that would aid them in 
deciding whether or not to sell it in 
the US. 

This article is based on our evalua- 
tion of a PC-8001 that some col- 
leagues purchased in Japan. When we 
first received it, we were bewildered 
because all the instructions and docu- 
mentation were in Japanese (with 
only the BASIC commands in 
English). After several months of 
poking, playing, and progamming, 
some syllabie-by-syllable translitera- 
tions of the katakana (a Japanese 
syllabary) instruction manual, and a 
few puzzled visits to Hiro, a Japanese- 
American co-worker, we believe that 
we have a good understanding of the 
PC-8001's most important features, 
its strong points, and its limitations. 

Photo 1 shows the basic com- 
ponents of the computer. It consists 
of two units: a keyboard (including 
both the processor and memory) and 



The processor Is an 

NEC version of the Z80 

running at 4 MHz. 



a color monitor, and it features a 24 
K-byte version of Microsoft BASIC in 
ROM (read-only memory). The dol- 
lar equivalent prices of the keyboard 
unit and monitor are $700 and $910, 
respectively. [These prices, however, 
may be only distantly related to the 
final price of the American version of 
this microcomputer. . . . G VV/ 

Keyboard 

The eighty-two-key keyboard has a 
high-quality standard English alpha- 
bet keyboard, five user-definable 
function keys, and a separate numeric 
keypad. In the normal mode, the user 
can enter uppercase and lowercase 
Roman characters; if he presses a 
locking shift key, he can enter char- 
acters in the Japanese katakana sylla- 
bary as well. Pressing a letter key and 
the nonlocking "graph" key causes 
one of a set of graphic characters to 
be displayed; this set includes bars, 
arcs, crosses, hearts, spades, clubs, 
and diamonds. (Although the kata- 



kana character set may appear useless 
to most American users, the char- 
acters are visually interesting and 
nicely augment the set of graphics 
characters.) All the characters avail- 
able are shown in photo 2. There is 
also a reset button on the back of the 
console, so it can't be hit accidentally. 

Inside the keyboard unit, the most 
noticeable feature is the switching 
power supply, which is mounted in a 
long, thin metal cage (approximately 
38 by 6.35 by 3.175 cm [15 by 2Vi by 
IV* inches]) extending along the en- 
tire rear of the keyboard enclosure. 
(See photo 3.) The elongated shape 
allows the entire power supply to be 
suspended over the printed-circuit 
board under the only portion of the 
cabinet that can be vented. During 
operation, however, the power 
supply remains cool. 

The 22.9 by 38.1 cm (9 by 15 inch) 
printed-circuit board has three 
layers, but the center layer does not 
appear to be nearly as extensive as the 
other two layers. There are at least 
sixteen test-point posts staked into 
the board. 

Most of the integrated circuits are 
mounted directly on the board, but 
the circuits that are either expensive 
or might have to be replaced (the 



72 January 1981 © BYTE Publications Inc 



memory, central processor, DMA 
[direct-memory access] controller, 
USART [universal synchronous/ 
asynchronous receiver-transmitter], 
video display device, and font mem- 
ory) are all in sockets. The board is 
easy to remove because all connec- 
tions to it — power, keyboard, beep- 
er — are made with plugs and sockets; 
there are no external connections or 
even jumpers soldered to the board. 

The processor is an NEC version of 
the Z80 running at 4 MHz. The 
BASIC ROM occupies the 24 K bytes 
of memory from hexadecimal 0000 to 
5FFF, and hexadecimal locations 6000 
to 7FFF are available for an expansion 
ROM. Standard programmable mem- 
ory extends from hexadecimal loca- 
tions C000 to FFFF, with locations 
8000 to BFFFF available for expan- 
sion. The board has empty sockets 
available for both expansion ROM 
and programmable memory. A time- 
of-day clock is included on the board 
(see figure 1). 

The video controller is a custom 
NEC integrated circuit. There are two 
separate video output connectors on 
the back of the keyboard unit. A 
5-pin DIN (Deutsche Industrie Norm) 
connector provides a baseband video 
signal for a black and white monitor 
and a similar 8-pin connector pro- 
vides red-green-blue signals for a col- 
or monitor. With a black and white 
display, colors appear as different 
shades of gray. 

In addition to a video-out signal 
and ground, the 5-pin connector pro- 
vides V DD ( + 12 V) and horizontal 
and vertical sync signals. The 8-pin 
connector provides V DD , ground, 
color-clock signal, horizontal and 
vertical sync signals, and red, green, 
and blue signals. Although the color 
monitor has an audio amplifier and 
speaker, the processor does not use 
them. The only sound made by the 
PC-8001 is provided by a 2-inch 
speaker mounted on the power sup- 
ply. The user can only control the 
duty cycle of a fixed-frequency 
beeper. 

Another DIN connector and an 
adapter cable provide an interface to 
any standard cassette recorder for 
program loading and storage. The en- 
coding scheme is 600 bps (bits per sec- 
ond) FSK (frequency shift keyed) 
Kansas City format (which uses 1200 
and 2400 Hz frequencies). This en- 
coding scheme is very robust — unlike 
many computers, almost any volume 
setting on the tape recorder is okay. 



A relay inside the console controls the 
tape recorder motor (or any other 
motor for that matter— a MOTOR 
command in BASIC allows a user to 
toggle this relay). 

A 16-pin socket on the printed- 
circuit board serves as an RS-232C 



connector, while cutouts at the back 
of the cabinet give access to a pair of 
edge connectors on the board. One is 
for a printer and one is a DMA chan- 
nel. An expansion unit is available to 
interface the DMA channel to up to 
four disk drives, two RS-232C serial 




Photo 1: The NEC PC-8001 personal computer system. Shown here is the basic system: 
high-resolution color monitor, keyboard unit, and documentation (reference manual, 
BASIC manual, and BASIC reference card). 



* in see 

Wiln U37','*H)97' ' = m AY**HiOWWHttArt: ?'4? iUmim IQT/ ' - m AT4WtO\ 
HttVtA iWSWWiV * WW, 

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wyuu . 



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RSTUVHXYZ[« A _ 



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IIIIW3tO--I Ir.Un-' * aJHttir M ' ' In"*-' 



Photo 2: A display illustrating the colors and the character set on the PC-8001. In addi- 
tion to complete ASCII, there are various graphics characters, control characters, and 
katakana characters. 



January 1981 © BYTE Publications Inc 73 




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• Phone Ordering/For added convenience, 
CompuMart maintains a toll-free ordering 
number. 1-800-343-5504. 

• Phones open M T W Th F 8:30 a.m. - 7:00 
p.m. Sat. 11:00 a.m.- 4:00 p.m. 



Compumart will throw in 

a FREE fabric ribbon and 

Currier 72 element when 

you buy a NEC from us. 



We've got the following Lear 
Siegler Terminals In Stock at prices 
too low to print— Call for quotes. 

ADM-3A Industries favorite dumb terminal tor 
some very smart reasons. 
ADM-3A.+ New from Lear Siegler. CALL! 
ADM-31. The terminal that's too smart to 
be considered dumb. 

ADM-42. Available with keyboard or without, 
semi intelligent terminal offering tremendous 
user flexibility. The optional configurations 
are amazing. Ca( | f Q| . details. 

Limited Time Offer 

We've slashed our Hazeltine prices 

again! 

Hazeltine 1410 List $850 CompuMart $749 

Hazeltine 1420 List $995 CompuMart $825 

Hazeltine 1500 List $1095 CompuMart $965 

Hazeltine 1510 List $1395 CompuMart $1135 

Hazeltine 1520 List $1585 CompuMart $1199 

Hazeltine 1552 List $1395 CompuMart $1235 

Calculators 

HEWLETT-PACKARD'S HP-41C 

HP-41C Calculator $288.00 

The System 

Memory Modules. For storing programs or up to 

2,000 lines of program memory $45.00 

"Extra Smart" Card Reader. Records programs 

and data back onto blank mag-cards $199.00 

The Printer. Upper and Lower case, High 
resolution plotting, Portable Thermal operation 

$355.00 

Application Modules $45.00 EACH 

Texas Instruments TI-99/4 

Home Computer 
Save $300 on this 16-Bit computer with 
monitor 



TI-99/4 w/o Monitor 



$659 



NOVATION CAT™ 

ACCOUSTIC MODEM 

• Answer Originate • Bell 108 

• 300 Baud . Low Profile Design 
Looks good, works great! $179.00 

NEW! D-CAT 

Direct Coupler from NOVATION $199. 



Monitors 



EXCLUSIVE from CompuMart! 

Special Offer. Zenith Color Video 
Monitor for $379! 

NEW FROM SANYO — Four Great Moni 
tors at Low CompuMart Prices. 
Sanyo's new line of CRT data display monitors are 
specifically designed for the display of alpha- 
numeric or graphic data. 
9" Sanyo Monitor $169 
12" Sanyo Monitor $289 
12" Sanyo Monitor with green screen 
$299 

13" Sanyo Color Display Monitor 
$495 





Computers 



[apple 



We carry the most complete inventory 
of Apple computers, peripherals, and 
software. CALL! 

Our Best Selling Apple System: 

Save over $250 on our most popular 

Apple System. System! includesa 48K 

Apple II. Apple Disk & Controller, and 

a Sup R Mod RF Modulator. 

List: $2,020 

Compumar! Sale Price: $1,769 

New from Apple tor the Apple II: 

DOS 3-3 Convert disks to 16 sector format for 23% 

more storage and faster access S60 

Apple Plot. The perfect graphic complement for 

Visicalc. $70 

Dow Jones News & Quotes $95 

Adventure (Uses 48K) $35 

DOS Tool Kit $75 

Apple Fortran $200 

Silentype Printer w/Xface $595 

Visicalc $149 

Tax Planner $120 

From Symtech & Info Unlimited 

Supersound Generator (mono) $159 (stereo) $259 

Light Pen $249 

X-10 Controller (plugs into paddle port) $49 

From Personal Software 

Visicalc $149 

Desk top plan $99 

New from Videx! — Video Term 

80 Col. x 24 line 

7x9 matrix, plug in compatible board for the Apple 

II. Price $325 without graphics EPROM. With 

graphics EPROM $350. 

New from MUSE 

The Voice $39.95 

Super Text $99.00 

Address Book $49.95 



Mountain Hardware — Expansion accessories for 
your Apple 

lntrol/X-10 System $289 

Super Talker $299 

The Music System $545 

ROM plus board w/keyboard filter $199 

Clock Calendar S280 

16 Channel A to D Converter $350 

Apple Expansion Chassis $650 

ROM Writer $175 
Miscellaneous Apple II Accessories: 

Easy Writer (80 col. need Videx) $249 

Easy Mover $ 49 

Easy Mailer $ 69 

Dysan Diskettes ea. $ 5 

S.S.M. Serial & Parallel Apple Interface $225 

ABT's Numeric Key Pad $110 

COMMODORE 



Buy direct from the biggest — Compumart has deliv- 
ered more Commodore computers in the U.S. than 
any other dealer. We were Commodore's first dealer 
and carry everything Commodore manufactures. In 
stock for immediate delivery! Call us now for low 
prices and special deals. 
NEW FOR PET: 

Visicalc (Need 32K and a disk drive) $199 

Word Pro 1, 529.95 • Word Pro 2. $99.95 • 
Word Pro 3. $199.95 • Word Pro 4, $299.95 • 




The Amazing 

HP 85 



Hewlett-Packard's Personal Computer for Industry. 
This extremely portable computer features ex- 
tended BASIC lo solve your problems quickly and 
efficiently along with an advanced graphics sys- 
tem to enhance communication. 
We carry H.P. Peripherals (Disk Drives to Graphics 
Plotters) Enhancements: (BASIC Training, General 
Statistics, Financial Decision, Math, Linear Program- 
ming $95 ea.); HP-85 Accessories: (Enhancement 
ROMs, ROM drawer, Overhead Transparency Kit); 
Supplies: (Plotter Pens, Tape Cartridges); Interface 
Modules (HP-IB Interface, HP-IB Interconnect 
Cables. Serial (RS-232C) 
Interface Module). 



We can get your every 
HP peripheral made for the 
HP-85. CALL FOR 
COMPLETE DETAILS 
& SPECS. 






3 Ways to save when you buy 

the Atari 800 from us. Choose from 

one of the following offers. 



ATARI 



1 ) Free 8K of memory with purchase. 
(So your Atari will come to you with 24K.) 

2) Free 410 program recorder with purchase ($89.95 
value). 

3) $100 off Atari Disk Drive purchase. 

ATARI 800 Personal Computer 
System — 

Comes with 800 Operators Manual, 16K RAM 
Memory module, 10 K ROM Operating System, 
power supply, TV Switch Box. $950. 

PERIPHERALS 

Atari 410 Program Recorder (FREE w/purchase of 

Atari 800) $ 89.95 

Atari 810 Disk Drive ($100 off with purchase) 699.95 

New Dual Disk double density 1499.95 

825 Printer (Centronics 737) 995.00 

RS232 Interface w/Cable 249.95 

NEW! Light Pens 74.95 

New! Visicale for Atari $199. 



EXIDY SUPER SALE! 

We want to clean out our inventory of Exidy com- 
puters and peripherals. To do this we've priced our 
Exidy equipment so low you'll have to call us for 

prices. 

ROCKWELL AIM 65 

The single board development system 
that's perfect in the classroom or lab. 

Our AIM System includes: 4K AIM with BASIC 
interpretor assembler, Power Supply, Cassette 
recorder & Enclosure $799. 



4K AIM — 65 

PL65 High Level Language 

Paper for the AIM (roll) 

Rockwell's 4-slot Motherboard (SALE) 



$499 
$125 
$ 2.50 
$175 



CompuMart's Microflex 65 System for your AIM 
Includes: Adapter Buffer Module w/ 4-slot module 
stack, 8K RAM module, 16K PROM/ROM module, 
Asynchronous communications Interface, & Power 
Supply $1,299 

Call or write for 
our complete 
Microflex 65 
brochure 




Piggy-back 
for the AIM 



NEW! The PMC-80 
The new 12K computer 
that's SOFTWARE 
COMPATIBLE with 
the TRS-80.* 

Level II 16K at $645 

Just think, now you can choose from the thousands 
of software packages already developed for the TRS- 
80 and run them on a computer costing only $645. 
But the PMC-80 is more than just a computer that 
accepts TRS-80 software. Its features include: Reads 
all Level II BASIC tapes. Reads all SYSTEM tapes. 
Full range of peripherals. Video output for monitor 
and TV. Optional FASTLOAD at 8000 baud. Optional 
Upper/Lower case. Call for complete specs. 
"TRS-80 is a registered trademark of 
Tandy Radio Shack 



Phones 
open from 
8:30 a.m. to 
7:00 p.m., Mon.- 
Fri.; 11:00 a.m. - 4:00 
p.m. Sat. P.O.'s accepted 
from Dun & Bradstreet 
rated companies - shipment 
contingent upon receipt of signed 
purchase order. Sale prices valid for 
month of magazine date only - all prices 
subject to change without notice. Our Ann 
Arbor retail store is open 11:00 a.m. to 7:00 
p.m. Tues.-Fri., 10:00 a.m. to 5:00 p.m. Saturdays. 
Stop by and visit. 





^^\J§}tli^^Ji}/ir\a\ I Circle 40 on inquiry card 

270 THIRD ST., DEPT. 113, P.O. BOX 568, CAMBRIDGE, MA. 02139 x 




Member Computer Dealers Assoc. 




We've had a reputation for dependability since 1971 




Photo 3: Inside the keyboard unit. The bottom of this photo corresponds to the front of 
the keyboard. Along the top edge is the power supply and, below it, the main printed- 
circuit board. The reset button can be seen at the rear of the keyboard near the power 
cord. 



We don't play hard to get 



gpaaoa etsgDcaags 1[@^mb ] 



MQGas 



SE)GD(3^fi?O0[a I 




Fast, reliable delivery 
of personal computer 
software programs. 

If you have an Apple or TRS-80 
computer, Minnesota Software Inc. has 
hundreds of programs — in stock and 
available right now by mail order. 

Choose from entertainment, learning or home-application programs. All software 
is immediately available and features a money back guarantee. 

TO GET A COPY OF OUR NEW CATALOG, CONTACT JOHN WEST. 
PHONE 612/426-0916. SOURCE- TCH122. MICRONET - 70040,555. OR DROP 
US A NOTE. 

MINNESOTA SOFTWARE, INC. 

5422 Fisher St. White Bear Lake, MN 55110 

Apple is a registered trademark of Apple Computers. TRS-80 is a registered trademark of Radio Shack. A Tandy Corp. 



IM-BASIC, written by 
Microsoft, is a floating- 
point BASIC capable of 
operating in either 
single or double 
precision. 



ports, a parallel port, and an IEEE 
(Institute of Electrical and Electronics 
Engineers)-488 bus (see figure 2). 

Monitor 

Everyone who has seen the NEC 
color monitor has commented favor- 
ably on its convergence and overall 
quality of construction. The CRT 
(cathode-ray tube) is a 30.48 cm (12- 
inch) diagonal tube and has an in-line 
gun structure and dot screen face with 
12-mil (0.012-inch) dot spacing. The 
deflection yoke is the precision 
wound torodial type. Convergence is 
excellent: during construction, 
wedges were inserted between the 
yoke and the neck of the tube to shim 
the yoke into correct alignment. 

The chassis is transformer power- 
ed. Almost all the electronics are 
mounted on one large single-sided 
printed-circuit board. The horizontal 
scan frequency is 15,974.4 Hz, and 
the vertical scan frequency is 60 Hz. 
The monitor uses an RGB (red- 
green-blue) signal interface with 
separate horizontal and vertical sync 
signals. All signals are at TTL 
(transistor-transistor logic) levels. 
Although the monitor has an audio 
amplifier and speaker, the audio line 
on the connector is tied to V DD on the 
Z80 microprocessor. The computer 
generates a format of up to 80 char- 
acters per line and 25 lines, noninter- 
laced. The image quality is excellent, 
as can be seen from photo 2. 

The monitor power supply ap- 
parently has some sort of time delay 
element, either intentionally or unin- 
tentionally, that prevents the user 
from turning on a set that is still 
warm. If you turn the monitor off 
and then try to turn it back on again 
without waiting a minute or so, the 
screen remains dark. 

Software 

As mentioned previously, the 
BASIC by Microsoft, called N- 
BASIC, is contained in three 8 K-byte 
ROMs. Contained within these 24 K 



76 January 1981 © BYTE Publications Inc 



Circle 41 on inquiry card. 



Circle 42 on inquiry card. 




SYBEX SPEAKS YOUR LANGUAGE . . . 



THE PASCAL HANDBOOK by Jacques Tiberghien 

— A dictionary of every Pascal instruction, function, 
operator and reserved word covering virtually all 
versions of Pascal. 300 pp., 150 III., Ret. P320, 7"x9", 
$14.95 ■ 
INTRODUCTION TO PASCAL (Including UCSD 
PASCAL) by Rodnay Zaks — A step-by-step introduc- 
tion for anyone wanting to learn the language of 
PASCAL. Describes UCSD and Standard Pascals. 440 
pp., KK) III., Ref. P310, 7"x9", $12.95 ■ 
INSIDE BASIC GAMES by Richard Mateosian - 
Uses a games format to teach program design in 
BASIC. Games run on TRS-80, APPLE II, PET/CBM 
and others. 300 pp., 1 00 III., Ret. H245, 7"x9", $13.95 ■ 
FIFTY BASIC EXERCISES by |.P. Lamoitier 
Teaches BASIC by actual practice using graduated 
exercises drawn from everyday applications. All ex- 
ercises written in Microsoft BASIC. J00 pp.. 140 III., 
Ret. B250, 7"x9", $12.95 ■ 
THE CP/M HANDBOOK by Rodnay Zaks - Com- 
plete instructions and reference handbook for CP/M 

— the industry standard in microcomputer operating 
systems. 336 pp., 100 III., Ref. C300, 5W'x6W, $13.95 ■ 
PROGRAMMING THE Z80 by Rodnay Zaks - A 
complete course in programming the Z80 
microprocessor and a thorough introduction to 
machine language. 620 pp., 200 III., Ref. C280, 
5'//'x8'/..", 2nd Ed. $14.95 ■ 
PROGRAMMING THE 6502 by Rodnay Zaks - 
Machine language programming of the 6502 from 



basic concepts to advanced data structures. 392 pp 
160 III., Ref. C202, 5W"x8'//', 3rd Ed., $12.95 I 

6502 APPLICATIONS BOOK by Rodnay Zaks - 
Real life application techniques: the Input/Output 
book for the 6502. 288 pp., 207 III., Ref. D302, 
5'//'x8'//', $12.95 ■ 

6502 GAMES by Rodnay Zaks — Third in the 6502 
series. Teaches advanced programming techniques 
using games as a framework for learning. (04 pp., 140 
III., Ref. G402, 5l4"x8lV', $12.95 ■ 

YOUR FIRST COMPUTER by Rodnay Zaks - The 
most popular introduction to small computers, what 
they do and how to buy one. 280 pp., ISO III,, Ref. 
C200A, 5'/j"x8'/i", 2nd Ed., $7.95 ■ 

MICROPROCESSORS: FROM CHIPS TO SYSTEMS 
by Rodnay Zaks — Covers components, concepts 
and techniques from basic to advanced. 420 pp., 257 
III., Ref.C201,5 l /i"x8Vi", 3rd Ed., $10.95 ■ 

MICROPROCESSOR INTERFACING TECHNIQUES 
by Austin Lesea, Rodnay Zaks — Hardware and soft- 
ware interconnect techniques including D to A con- 
version, peripherals standard buses and 
troubleshooting. 464 pp., 400 III., Ref. C207, 5Vi"\»Vi", 
3rd Ed., $15.95 ■ 

PROGRAMMING THE Z8000 by Richard Mateosian 
— Architecture and function of the Z8000 and its 
family of support chips. Includes programming in 
Z8000 machine language. 312 pp., 124 III., Ref. C281, 
5'/j"x8'/j", $15.95 ■ 



tfsVBE 



MAIL TO: SYBEX 

DEPT. B1 % _ 

2344 SIXTH STREET ^^^T 
BERKELEY, CA 94710 
Phone Orders: 415/848-8233 



NAME 

ADDRESS. 
CITY 



D SEND ME YOUR FREE CATALOG 



STATE 



ZIP 



ADD D $1 .50/book UPS or D 75</book 4th class mail (CA add tax) 
OR CHARGE MY D VISA □ MC □ AM EX. CARD NO 



Total Amt. Enclosed. 



SIGNATURE 



EXP. DATE. 



bytes of ROM is a very complete 
BASIC, as well as a system monitor 
program. Advertisements in the 
Japanese computer magazine ASCII 
indicate that a number of user pro- 
grams (including a color version of 
the ever-popular Space Invaders) are 
readily available on tape. 

N-BASIC is a floating-point BASIC 
capable of operating in either single 
or double precision. All the features 
of standard BASIC are present, along 
with a few interesting extensions, 
such as: 

• SWAP: exchanges value of two 
variables; 



The PC-8001 has one 
feature that ought to 
be Included In all per- 
sonal computers: a 
single BASIC command 
that changes It from a 
computer to a terminal. 



• BEEP, MOTOR: toggles beeper or 
motor relay; 

• HEX$: decimal to hexadecimal con- 
version; 

• STRINGS (X,Y): string equal to X 



copies of the character with ASCII 
(American Standard Code for Infor- 
mation Interchange) code Y. 

In addition, there is a whole set of 
graphics and display commands that 
will be described further. 

There is also a monitor program 
which gives the user direct access to 
the Z80 machine code. After entering 
the monitor by typing MON, the user 
can test, manipulate, load or store 
bytes of blocks of memory using the 
commands in table 1. 

Another useful feature of N-BASIC 
is the use of the ESC (escape) key on 
the keyboard as a pause function. It 



PC - 8001 



r 



CPU 
780-1 



RAM 
/iPD4161-3 



c 



ROM 
^PD2364 



TIMER 
/1PD1990 



CASSETTE 
INTERFACE 



SPEAKER 



P 



RS232C 



PRINTER 
INTERFACE 



MODEM, 
ETC. 



SERIAL 

I/O 

INTERFACE 



SYSTEM BUS 



KEYBOARD 



L^ 



DMAC 

/iPD 

8257 







DISK 
DRIVES 


» 


h_rl Hs~\ 

DISK 
DRIVES 


I 








DISK 
INTERFACE 





OR 



CRTC 
fiPD 
2301 



CHARACTER 
GENERATOR 



HORIZ. 

AND 

VERTICAL 

TIMING 

INTERFACE 



RGB 

COLOR 

MONITOR 



EXPANSION 
UNIT 



■IEEE488 
-RS232C 
-PARALLEL I/O 



±1 



RF MOD- 
ULATOR 



BSW 
TV 



tl 






E3 S3 

DISK 
DRIVES 


— »> 


DISK 
DRIVES 



Figure 1: Block diagram of the NEC PC-8001 system. The modules within the dotted lines are contained in the PC-8001 keyboard 
unit. 



POST-HASTE MAILING LIST 

Software written in UCSD Pascal * 



• 3 lines of address 

• Ability to handle foreign addresses 

• Address lines 35 characters long 

• List on 80 or 132 character printer 

• Print 1, 2, 3 or 4-up labels 



• Access records by full or partial name 

• Update files with screen-oriented input 

• 50 character user definable field 

• Select records using complex select criteria 

• Sort selected records on up to 6 fields 



These are some features of our professional mailing list package, the Post-Haste Mailing List. It is designed to 
meet the demand of users of both large and small mailing lists. The mailing list file is indexed by a B+ tree 
for fast record retrieval and may contain in excess of 40,000 records if the disk space is available. 

Post-Haste Mailing List $100. Also available, PFAS, key file access for CJCSD Pascal from $100. 

C.J. WIGGLESWORTH SOFTWARE, P.O. Box 755, Cardiff-by-the-Sea, CA 92007 

"UCSD Pascal is a Trademark of the Regents of the University of California. 

Circle 43 on Inquiry card. 



78 January 1981 © BYTE Publications Inc 



Circle 44 on Inquiry card. 



Multi-User 



UniFLEX is the first full capability multi-user 
operating system available for microprocessors. 
Designed for the 6809 and 68000, it offers its 
users a very friendly computing environment. 
After a user 'logs-in' with his user name and 
password, any of the system programs may be 
run at will. One user may run the text editor 
while another runs BASIC and still another runs 
the C compiler. Each user operates in his own 
system environment, unaware of other user 
activity. The total number of users is only 
restricted by the resources and efficiency of the 
hardware in use. 



I 





Support 



The design of UniFLEX, with its hierarchical file 
system and device independent I/O, allows the 
creation of a variety of complex support 
programs. There is currently a wide variety of 
software available and under development. 
Included in this list is a Text Processing System 
for word processing functions, BASIC interpreter 
and precompiler for general programming and 
educational use, native C and Pascal 
compilers for more advanced programming, 
sort/merge for business applications, and a 
variety of debug packages. The standard 
system includes a text editor, assembler, and 
about forty utility programs. UniFLEX for 6809 is 
sold with a single CPU license and one years 
maintenance for $450.00. Additional yearly 
maintenance is available for $100.00. OEM 
licenses are also available. 



FLEX 



Multi-Tasking 



UniFLEX is a true multi-tasking operating system. 
Not only may several users run different 
programs, but one user may run several 
programs at a time. For example, a 
compilation of one file could be initiated while 
simultaneously making changes to another file 
using the text editor. New tasks are generated 
in the system by the 'fork' operation. Tasks may 
be run in the background or 'locked' in main 
memory to assist critical response times. Inter- 
task communication is also supported through 
the 'pipe' mechanism. 



UniFLEX is offered for the advanced 
microprocessor systems. FLEX, the industry 
standard for 6800 and 6809 systems, is offered 
for smaller, single user systems. A full line of FLEX 
support software and OEM licenses are also 
available. 



chnical /y/tenrv 
LfflrS jltantr, inc. 

Box 2570, West Lafayette, IN 47906 
(317)463-2502 Telex 276143 

'"UniFLEX and FLEX are trademarks of Technical 
Systems Consultants, Inc. 



Circle 45 on inquiry card. 



MBC Systems, Inc. 

(203) 342-2747 




NORTH STAR HORIZON: 

HRZ-2-32K-D-Factory ASM$2275 
HRZ-2-32K-Q-Factory ASM$2675 
64K DD or Q Also Available 

HDS-18-F $4449 

Northword DQ $ 295 

INFO-Manager $ 365 

Mail Manager $ 235 

General Leger $ 775 

ACC. REC. OR ACC. PAY . . $ 445 

Word Star $ 350 

Medical-Dental SYS $2500 




COMMODORE 



2001-32K-BorN Keyboard $1090 
8K and 16K Also In Stock!!!! 
8032 (80 Column Screen) $1599 
2040 Dual Floppy Drive $1090 
8'050 Dual Floppy (1MEG)$1599 
2022 Tractor Printer... $ 749 

Word PRO IV $ 290 

VISICALC $ 195 

APPLE II PLUS Call For Price! 



ATARI 800 $ 849 

TI 99/4 Console&Monitor . . $1190 



INTERTEC SUPERBRAIN: 

32K RAM $2595 

64K RAM $2795 



PRINTERS 

Letter Quality: 

NEC 5510 or 5530 $2550 

NEC 5520 KSR $2950 

DIABLO 630 $2390 

C.ITOH $1690 

Dot Matrix: 

CENTRONICS 730 $ 629 

" " 737-1 $ 849 

" " 799 $999 

EPSON MX-80 $ 599 

PAPER TIGER 460G $1250 

BASE II MST $ 64 9 



DISPLAY TERMINALS 

HAZELTINE 1420 $ 949 

" " 1500 $ 999 

INTERTUBE III $ 775 

TELEVIDEO 920C $ 849 



Since 1977 complete sales and 
service. Most items in stock, 
prices are subject to change. 
Visa and Master Charge welcome 
Most items shipped by UPS. 

MBC Systems, Inc. 

28 MARLBOROUGH STREET 
PORTLAND, CONN. 06480 



(203)342-2747 TWX 710-428-6345 
M-F 9-6 SAT. 9:30-3:00 



can be used to pause in the middle of 
a program execution, program 
listing, monitor dump, and just about 
any other process. Pressing ESC 
again resumes the program or listing. 
This is very handy for debugging or 
for reading parts of a long program 
listing. 

Finally, the PC-8001 has one 



feature that ought to be included in 
all personal computers: a single 
BASIC command that changes it 
from a computer to a terminal. The 
TERM command allows the user to 
select either ASCII or JIS (Japanese 
Industry Standard) coding, parity, 
and clocking options. A jumper in- 
side the keyboard unit selects data 



- 



Command Meaning 

S xxxx displays the byte whose address is xxxx and changes it to the value to be 

entered 
D xxxx, yyyy displays the hexadecimal values stored in locations xxxx to yyyy 
G xxxx goes to byte xxxx and starts executing 

W xxxx, yyyy writes to tape the block from xxxx to yyyy 
L loads a stored block from tape back to memory 

LV loads a stored block from tape and verifies that it has been correctly 

loaded 
TM tests memory and returns to BASIC 

control-B returns to BASIC 



Table 1: Monitor commands within the NEC PC-8001. These commands 
available to the user for work in machine-language programming. 



are 



CONSOLE <T>, <N>, <K>, <M> 
Sets the following display parameters: 

T =top line of scrolling window 

N = number of lines in scrolling window 

K =key list flag; if 1, displays identity of programmable function keys 

M = color mode: 1 = color, = black and white 

COLOR <C>, <B>, <M> 
Sets the following parameters: 
C = color (or attribute in black and white mode): 



In Color Mode: 
= black 
1=blue 

2 = red 

3 = magenta 

4 = green 

5 = cyan 

6 = yellow 

7 = white 



In Black and White Mode: 
Bit = visibility (0 = visible) 
Bit 1 = flashing (1 = flash) 
Bit 2 = reverse video (1 = reverse) 



For example, color 6 in black and white mode would pro- 
duce flashing, reverse-video characters. 



B = background character; fills the background with the character whose ASCII code is 

B. 
M = mode flag, 1 = graphics mode, = text mode 

WIDTH <H>,<V> 

sets screen format (H by V); (H = 80, 72, 40, or 36; V = 25 or 20) 

LOCATE <X>, <Y> 

moves cursor to character position (X,Y) 

PSET(<X>, <Y>, <C>) 
draws a graphics dot at graphics coordinate X,Y in color C 

PRESET (<X>, <Y>) 

erases a graphics dot at X,Y 

LINE(<X1>, <Y1>)-«X2>, <Y2>), "<char>", <C>,[B[F]] 

Draws a line from (X1.Y1) to (X2,Y2). The line is a line of text characters "char". If 
"char" = PSET or PRESET, the line is a graphics line and X and Y are interpreted as 
graphics coordinates. <C> is the color of the line. If present, B causes a rectangle 
(block) to be drawn with (X1.Y1) and (X2.Y2) as opposite corners, and F causes the 
rectangle to be filled. 

GET @ (<X1>, <Y1>)-(<X2>, <Y2>), X 
stores characters from the specified rectangular area of the screen into array X 

PUT @ (<X1>, <Y17>)-(<X2>, <Y2>), X 
puts characters from array X to the display 

Table 2: Commands for color-graphics display from within N-BASIC. 






80 January 1981 © BYTE Publications Inc 



Circle 46 on Inquiry card. 



ew muscle 
for Heathk it 



Now with new CPIM Systems Software 

for thousands more programs... and new 

8-inch disk system for millions more bytes. 




The Heathkit All-ln-One Computer now has space 
for 64K of addressable RAM, so you can run bigger, 
more complex programs. 

And our new CP/M'-' Operating System (Standard 
ORG-0, Version 2.2) makes thousands of CP/M pro- 
grams available to you. Heathkit systems can run 
more, do more, store more than ever before. 
A new 8-inch double-sided, double-density disk sys- 
tem, with over 1 million bytes per drive, is now avail- 
able for Heathkit H-89 and H-8 Computers. 
The new 8-inch disk system features soft-sectored 
disks for IBM"" compatibility. It's capable of operat- 
ing in standard IBM 3740 format. And the 8-inch sys- 



VISIT YOUR HEATHKIT STORE 

Heathkit products are displayed, , — - 
sold and serviced at Heathkit 
Electronic Centers*, located in 
major cities throughout the U.S. ' 
and Canada. See your white 
pages for the store nearest you. 

'Units of Veritochnology Electronics 
Corporation, in tho U.S. 



tern can be used in conjunction with 5 1 /<i-inch 
systems. For compatibility with the rest of the in- 
dustry, Heathkit Computers may just be the most 
flexible systems you can buy. 

All Heathkit computers and peripherals are avail- 
able in money-saving, easy-to-build kit form — or 
completely assembled and factory tested. All are 
supported by the best documentation in the busi- 
ness and by 62 service centers throughout the U.S. 
and Canada. You're never out in the cold. 
For complete details and prices on Heathkit com- 
puters, peripherals and software, write today for 
the latest Heathkit Catalog or visit your 
-rx eFfflM nearby Heathkit Electronic Center*. 



[HeaSiH! 



Send for FREE catalog 

Write to Heath Company, Dept. 334-734, 
Benton Harbor, Ml 49022 

In Canada, contact Heath Co., I480 Dundns St. E., 
Mississauga, Ontario L4X 2R7 



Heathkit 



IBM is a rogistorod trademark ot International Business Machines Corporation. CP/M Is a trademark ol Digital Research, Inc. 



transfer rates of either 4800, 2400, 
1200, 600 or 300 baud; the function 
keys on the keyboard determine 
whether the terminal operates in half- 
or full-duplex modes. The only ap- 
parent deficiency is the lack of a shift 
lock key for the terminal mode. 



Graphic and Display Features 

The display features of the PC-8001 
include: 

• eight-color display (both text and 
graphics); 

• 248-symbol character set (complete 




Photo 4: Sample display created on the PC-8001 by the authors. Note the use of the 
Japanese characters for graphics — the little invaders are actually the Japanese characters 
for the word "minute." 




Photo 5: Illustration of some of the display restrictions of the PC-8001. See text for ex- 
planation. 



ASCII, katakana, and graphics char- 
acters — lines, arcs, card symbols); 

• variable screen format: (80, 72, 40, 
or 36 characters by 25 or 20 lines); 

• two display modes: text and 
medium-resolution (160 by 100 pix- 
els) graphics (these two modes can be 
intermixed on the same display); 

• flashing, reverse video, and 
underlined text. 

Table 2 lists the graphics and 
display-related extensions in the 
PC-8001 dialect of BASIC. These in- 
clude commands for cursor position- 
ing, changing various display pa- 
rameters, and plotting points and 
drawing lines in gaphics mode. Two 
particularly worthwhile instructions 
are GET and PUT. GET allows the 
user to store the image in a specified 
rectangular area of the screen in an 
array, which can then be PUT at 
another location on the screen. This 
allows the user to define complex 
shapes that can then be drawn on the 
screen with a single instruction. 
Repetitive erasure and redrawing of a 
shape also provides a simple method 
of animation. 

Photo 4 is a sample of what can be 
done with the PC-8001 graphics. This 
display uses most of the commands in 
table 2 and, in addition, illustrates the 
use of some of the Japanese characters 
for graphics purposes (the invader 
figures and the television speakers are 
made from these characters). 

Problems with Video Displays 

Upon further experimentation with 
the computer, we discovered that cer- 
tain graphics operations can some- 
times produce strange and unex- 
pected results. A sampling of some of 
the display anomalies which can oc- 
cur is shown in photo 5. The follow- 
ing unexpected things happen in this 
display: 

1. Each column of Xs in the upper- 
left corner should be a different color, 
but after eighteen columns, the dis- 
play remains in one color. 

2. The two pairs of intersecting lines 
should be the same, but in the one on 
the left, extra areas are colored in 
near the intersection. 

3. The width of the white diagonal 
line should stay constant, but it 
becomes much thicker in the middle. 

4. The two rows at the bottom left 
should be all dots, but some of the 
dots are printed as text characters. 

5. The figure on the right of the 



82 January 1981 © BYTE Publications lnc 



Circle 47 on inquiry card. 



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display should be a ring of concentric 
squares, each a different color, but 
the line thickness varies and some 
dots are replaced by text characters. 

The explanation for all these 
anomalies lies in the way the text and 
graphic information is represented in 
memory. For example, consider the 
full 80-character by 25-line screen for- 
mat. To represent a screen of infor- 
mation in memory requires storage 
space for 2000 characters and their at- 
tributes (color, flashing, etc). At 1 
byte for the character and 1 byte for 
its attributes this would require about 
4 K bytes of memory. However, only 
3 K bytes are allocated for screen 
storage (addresses F300 to FEB8) . The 
way these 3 K bytes of memory are 
organized explains all these display 
anomalies and also provides insight 



KEYBOARD/PROCESSOR 
UNIT 



into a useful feature that makes the 
PC-8001 unique. 

As shown in figure 3, each row of 
characters on the screen is repre- 
sented by 120 bytes in memory. The 
first 80 of these 120 bytes contain the 
ASCII codes for the 80 characters in 
the row. The remaining 40 bytes are 
organized into twenty pairs. We have 
not determined the use of the first 
pair, but the remaining nineteen pairs 
are used to encode up to nineteen at- 
tribute fields for that row. Each pair 
Pi points to the beginning of the field, 
which runs to position P 1+I — 1 (the 
Pi are always ordered so that 
Pi<P 2 < ...etc) and contains char- 
acters with attributes a, (where a, is 
the 1-byte attribute within pair P,). 

Whenever a program, in printing 
on the screen, uses up the first eigh- 
teen attribute fields for a row, all suc- 



PC-8001 



PC-8041 



PC-8043 



BASEBAND VIDEO 
MONITOR 



HIGH-RESOLUTION 
COLOR MONITOR 



PRINTER 



PC-8062 



RS-232C 



EXPANSION 
UNIT 




FLOPPY DISK 
DRIVES 



RS-232C 



ADDITIONAL 
I/O PORTS 



PARALLEL I/O 



Figure 2: Interconnection block diagram of the NEC PC-8001 system. While many 
peripherals can be directly connected to the PC-8001, disk drives and I/O ports must be 
connected through the PC-8011 expansion unit. 



84 January 1981 © BYTE Publications Inc 



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Circle 48 on inquiry card. 



BYTE January 1981 85 



The days of complicated, unreliable, 
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) Send me more information 



cessive characters on the same line 
that occur after these fields are given 
the attribute a, 9 . This is the default at- 
tribute for that row that is set to the 
current attributes in effect whenever a 
clear-screen command is received. 

This explains the first anomaly in 
photo 5. After eighteen different- 
colored columns, the computer "runs 
out of colors," and the remaining col- 
umns default to red. Red is not speci- 
fied in the program; it just happened 
to be the color in effect when the pro- 
gram started. 

Another problem occurs when 
plotting color graphics because the 



80 



PC-8001 has character-oriented (not 
bit-mapped) graphics. (In this re- 
spect, it is closer to the Radio Shack 
TRS-80 than to the Apple II, for ex- 
ample.) Each character space is divid- 
ed into a 4 by 2 array of cells, each of 
which can be "on" or "off." This pro- 
vides an alternate character set con- 
sisting of the 256 possible arrays of on 
and off cells. When points, lines, or 
graphics shapes are drawn, the com- 
puter automatically converts the 
points to the required graphics char- 
acters and displays these, thus pro- 
viding an effective graphics resolu- 
tion of 160 by 100 cells. 

















. 





o) 



65208 ■ 



120 BYTES 



ONE ROW 
OF SCREEN 



MEMORY 



BYTE 



80 
81 
82 
83 



b) 



119 
120 



CHARACTER CODE 1 



CHARACTER CODE 2 



CHARACTER CODE 80 






POSITION OF FIELD 1 



A] 



ATTRIBUTE BYTE 



P2 



POSITION OF FIELD 2 



A 2 



ATTRIBUTE BYTE 



Pl9 POSITION OF FIELD 19 



Aj9 DEFAULT ATTRIBUTES 



Figure 3: Format of the NEC PC-8001 memory-mapped video display. Figure 3a shows 
how each row of the video display translates into a block of programmable memory. 
Figure 3b shows how each 80-character row is stored in memory. A row can be broken 
into a maximum of nineteen fields, the position and attributes of which are described in 
the last 38 bytes of the memory associated with one row. All numbers shown are in 
decimal. See the text for further details. 



86 January 1981 © BYTE Publications lnc 





PUASANI 

MEMORY 

for f M-SC 
users 





MT-32 



printer/memory module 



Give something different this season — the 
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matrix printer or any other Centronics- 
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No hardware modifications. Attaching or 
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Three configurations are available: 

• Without RAM assembled and tested 
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Available from Microtek or your nearest 
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San Diego, CA 92123 
Tel. (714) 278-0633 
TWX 910-335-1269 
Outside California 
call toll free: 800-854-1087 




MICROTEK^ 



TRS-80 is the Registered Trademark of Radio Shack, Div. Tandy Corp. 



Circle 49 on inquiry card. 



BYTE January 1981 87 



However, a problem occurs when, 
for example, two lines of different 
colors intersect. Because a character 
cannot be two colors at the same 
time, the algorithm used by the com- 
puter gives the most recently plotted 
points precedence. Any cells within 
the same character space that are 
already "on" are changed to the new 
color. Thus, an adjacent pair of hori- 
zontal lines for which different colors 
are specified may be displayed in 
either the same or different colors, 
depending on whether or not they lie 
on opposite sides of a character cell 
boundary. We can show that this is a 



limitation of the software and not of 
the hardware video-controller device: 
the command OUT 63,41 (presum- 
ably an output to part of the video- 
controller device) fills the screen with 
adjacent horizontal lines of different 
colors. 

This also explains anomalies 2 and 
3 in photo 5. The two crosses look 
different because they intersect in dif- 
ferent positions relative to cell bound- 
aries. The white diagonal line changes 
width because it crosses a black 
graphics rectangle. Even though the 
black rectangle is invisible to the 
casual observer, it changes the ap- 



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pearance of the intersecting diagonal 
line: every cell in each character space 
changes to white. 

This alternative graphics-character 
set is selected with one of the bits in 
the attribute byte. This implies that 
the user can also "run out of 
graphics" on a horizontal line. This is 
what happens in anomalies 4 and 5 
(bottom and far right of photo 5). 
The default attribute byte happens to 
specify text mode. Hence the remain- 
ing characters on the line are dis- 
played as their text equivalents. 

It is unclear why the designers 
chose this display approach, par- 
ticularly since a full character- and 
attribute-mapped display would have 
required only 4 K bytes of memory 
instead of 3 K bytes. But even though 
this implementation imposes some re- 
strictions on the types of displays that 
can be generated, it also provides an 
interesting capability which, to our 
knowledge, is not found on any other 
personal computer. 

This capability is a consequence of 
the fact that the attributes of a char- 
acter on the screen are specified in- 
directly. That is, each character is 
identified with a field number which 
in turn is associated with an attribute 
byte. Thus, by a direct POKE into 
memory (a 1-byte change), the user 
can change an attribute (specifically., 
color) of a character or group of char- 
acters (up to an entire field) without 
altering the character or field codes. 
This allows a sophisticated method of 
animation called color table anima- 
tion in which the user first prints a 
number of images in different fields 
on the screen, then changes the color 
of the fields to make each image ap- 
pear in succession. As an example, we 
have written a BASIC program which 
animates a large flying saucer flying 
amidst a field of stars at 20 images per 
second. This is very fast for an inter- 
pretive BASIC animation. 

Summary 

The PC-8001 appears to be an at- 
tractive, well-planned, and well- 
made personal computer. The graph- 
ics, though somewhat rudimentary, 
are more than adequate for charting, 
graphing, and business applications, 
and they can do a creditable job on 
many games as well. Most people 
who have seen our PC-8001 feel that, 
if it were sold in this country, it 
would provide strong competition for 
any of the color-based home com- 
puters currently being sold.H 



88 January 1981 © BYTE Publications Inc 



Circle 50 on inquiry card. 



Circle 51 on inquiry card. 



Memory — you never seem to have quite 
enough of it. 

But if you're one of the thousands of Apple 
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16K ON A PLUG-IN CARD. 

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(206)454-1315. 





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> 1 . • • — 5 


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Technical Forum 



SC/MP Instruction Set Summary 



Professor Walter E Burton Jr 

Electrical Engineering Technology Department 

Southern Technical Institute 

Marietta GA 30060 



If you hand-assemble or debug programs for National 
Semiconductor's SC/MP processor, here is a simplified 
instruction-set summary to speed you on your way. 
Table 1 contains the hexadecimal codes, the standard 
SC/MP mnemonics, and the SC/MP addressing modes. 

Hexadecimal codes are separated into the high-order 
digits, which are in the left-hand column, and the low- 
order digits, which are in the top row. Mnemonics are 
located within the table. The abbreviation PTR refers to 



the four SC/MP pointer registers thru 3. The register 
numbers are associated with the related instructions in 
the same column in table 1. 

Different addressing modes associated with two-byte 
instructions are located along the bottom of the table. 
Blanks identify areas of illegal code. 

As a reference I used the SC/MP Technical Descrip- 
tion, Publication Number 4200079B (Santa Clara CA: 
National Semiconductor Corporation). ■ 



CO 

c 
o 

o 

3 

oo 

c 

CD 

>. 

CD 

<i> 
c 
O 

to 

c 
o 

o 

3 

o5 

c 

CD 

>. 

m 
6 
5 

1- 


High 

Hexadecimal 

Digit 


Low Hexadecimal 


Digit 





























1 


2 


3 


4 


5 


6 


7 


8 


9 


A 


B 


C 


D 


E 


F 







HALT 


XAE 


CCL 


SCL 


DINT 


IEN 


CSA 


CAS 


NOP 
















1 
















SIO 


SR 


SRL 


RR 


RRL 


2 












3 


XPAL 


XPAL | XPAL 


XPAL 


XPAH 


XPAH 


XPAH 


XPAH 


XPPC 


XPPC 


XPPC 


XPPC 


4 


LDE 












5 


ANE 


ORE 


6 


XRE 


DAE 


7 


ADE 


CAE 


8 




DLY 


9 


JMP 


JMP 


JMP 


JMP 


JP 


JP 


JP 


JP 


JZ 


JZ 


JZ 


JZ 


JNZ 


JNZ 


JNZ 


JNZ 


A 




ILD 


ILD 


ILD 


ILD 










B 


DLD 


DLD 


DLD 


DLD 


C 


LD 


LD 


LD 


LD 


LDI 


LD 


LD 


LD 


ST 


ST 


ST 


ST 


ST 


ST 


ST 


D 


AND 


AND 


AND 


AND 


ANI 


AND 


AND 


AND 


OR 


OR 


OR 


OR 


ORI 


OR 


OR 


OR 


E 


XOR 


XOR 


XOR 


XOR 


XRI 


XOR 


XOR 


XOR 


DAD 


DAD 


DAD 


DAD 


DAI 


DAD 


DAD 


DAD 


F 


ADD 


ADD 


ADD 


ADD 


ADI 


ADD 


ADD 


ADD 


CAD 


CAD 


CAD 


CAD 


CAI 


CAD 


CAD 


CAD 


PTR 





1 


2 


3 





1 


2 


3 





1 


2 


3 





1 


2 


3 


CO 
CO CD 

CD -o 
-So 
-a 2 
< 


a) 

> 

CD 
CE 

6 
5. 


T3 

a> 

X 

cd 
■o 

c 


3 
ra 

t5 

CD 

E 
E 


■o 

CD 
X 
CD 

■o 

c 

6 

3 
< 


CD 
> 

CD 
CE 

6 

Q- 


XJ 
CD 
X 
CD 

■o 

c 


'■a 

CD 

E 
E 


"O 
CD 
X 
CD 

T3 

c 

6 

•»— 
3 
< 






Table 1: In 


structic 


n set s 


ummar 


y for Nationa 


/ Semic 


onduc 


for's S( 


Z/MP 


process 


or. 









90 January 1981 © BYTE Publications Inc 



Circle 52 on inquiry card. 




*CQ 



tfVi 



ft ** 






;. ; 



G®^rTD^^ " VPH °" 



|8.P 



7 DAYS 9-6 I 

ORDERS 
CALIFORNIA, ALASKA, HAWAI 
OUTSIDE OF U.S. (714) 698 

NFORMATION, TECHNICA 
BORDERS, CALL (714) 698 



3 1IL.W S/lli/lnR I 



IISIE: 



800-854-6654 




jcipplc computer 

Authorized Dealer 








CHRISTMAS 

SUPER 

SALE 



[cippkz// 



ACCESSORY SPECIALS 



DISK II DRIVE (add-on) 425 

D.C. HAYES MICROMODEM II 319 

GRAPHICS TABLET 655 

INTEGER BASIC OR APPLESOFT II 
firmware card 149 

SILENTYPE PRINTER with Interface card. . 515 



APPLE II ACCESSORIES 



APPLE II PLUS 

OR APPLE II STANDARD 

16K cEffir $ *M 



•1049 



w/controller & DOS 3.3 

PASCAL 



♦529 
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microsoft Z-80 
SOPTCARD '299 



APPLE II SOFTWARE 



CENTRONICS PRINTER 

Int. card 185 

PARALLEL PRINTER Int. card145 
COMMUNICATION CARD 

w/conn. cable 185 

HI-SPEED SERIAL Int. card . . 145 
DAN PAYMAR lower case kit. 55 
MICROWORKSDS 65 

DIGISECTOR 339 

LAZER lower case adapter. ... 50 
SSM AIO SERIAL/ 

PARALLEL kit 155 

SSM AIO assembled & tested190 
SYMTEC LIGHT PEN SYSTEM215 
SYMTEC SUPER SOUND 

GENERATOR 225 

SVA 8 INCH DISK 

CONTROLLER CARD 335 

VERSA WRITER 

DIGITIZER SYSTEM 215 

VIDEX VIDEOTERM 

80 COLUMN CARD 315 

VIDEX VIDEOTERM 

w/graphics ROM 335 

LOBO DISK DRIVE ONLY... 385 
LOBO DRIVE 

w/cont. & DOS 3.3 499 

GPIB IEEE-488 11978) Int 259 

ARITHMETIC PROCESSOR 

CARD 335 

SPEECHLINK 2000 

(64 Word Vocab.) 215 



M&R SUP-R MOD 

TV MODULATOR 30 

CORVUS 10 MEGABYTE HARD 

DISK DRIVE SYSTEM 

w/pwr supply 4395 

CORVUS CONSTELLATION. . 595 
16K MEMORY UPGRADE KIT 
(TRS-80, APPLE II. 

SORCERER 60 

ABT NUMERIC INPUT KEYPAD 

(specify old or new kybrdl. 115 
ALF MUSIC SYNTHISIZER. . . 235 

BRIGHTPEN LIGHTPEN 32 

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80 COLUMN CARD 335 

SMARTERM 80 COL 335 

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card . 225 

SUPERTALKER SD200 SPEECH 

SYNTHISIZER SYSTEM. . . . 245 
ROMPLUS w/kybrd filter. . . . 165 
INTROUX-10 BSR REMOTE 

CONTROL SYSTEM 245 

INTROL/X-10 controller 

card only 165 

ROMWRITER SYSTEM 155 

MUSIC SYSTEM 

(16 voices/stereo) 465 

A/D-D/A 16 CHANNELS 319 

EXPANSION CHASSIS 

(8 slotsl 555 



VISICALC 120 

CCA DATA 
MANAGEMENT. 85 

THE CONTROLLER General 
Business System 519 

THE CASHIER Retail Manage- 
ment & Inventory system 199 

APPLEWRITERWord 
Processor 65 

APPLEPOST MAILING 
List system 45 

DOW JONES PORTFOLIO 
EVALUATOR 45 

APPLE CONTRIBUTED 

Volumes 1-5 w/manuals . . 30 
•DESKTOP/PLAN by DESKTOP 

COMPUTERS 85 

APPLEBUG ASSEMBLER/ 

DISASSEMBLER 75 

APPLE DOS TOOL KIT 65 

PIMS Personal Information 

Management System .... 23 
ADVENTURE by 

MICROSOFT 27 

SUB LOGIC FS-1 

Flight Simulator 34 

SARGON II Chess 

byHAYDENICass.) 27 



FORTRAN 165 

DOS 3.3 49 

APPLE PLOT .... 60 

TAX PLANNER 65 

SARGON II Chess 

on Diskette 32 

TRILOGY OF GAMES 27 

SPACE GAME ALBUM 38 

SPACE INVADER ICass.l. .18 
SPACE INVADER (Disk! ... 23 
SYBEX APPLE 80 

8080 Simulator 17 

FORTH II by PROGRAMMA 

SOFTWARE 45 

SINGLE DISK COPY 

ROUTINES 17 

APPLEBUG DEBUGGER. . . 27 
APPLESOFT UTILITY PRO 

GRAMS BY HAYDEN. ... 27 
The CORRESPONDENT. ... 35 

ASTEROIDS IN SPACE 19 

HEAD-ON 25 

3-D ANIMATION PACK 53 

BATTLESHIP 

COMMANDER 23 

FASTGAMMON 26 

STAR CRUISER 24 

TRANQUILITY BASE 24 

More software available 
Please write us for a list. 



Circle 53 on inquiry card. 




EXIDY 



ATARI 



Please 

Call 

For 

Best 

Price 



SORCERER II 
COMPUTER 



1B.32K 6 48K VERSIONS AVAILABLE 

S 100 EXPANSION UNIT 375 

WORD PROCESSING PAC 179 

DEVELOPMENT PAC 89 





PMC-80 




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THE TRS-80 WORK-ALIKE' 
16K LEVEL II ONLY $579 

Completely compatible with Radio Shack TRS-80 
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Level II Basic, Video & Ch. 3 TV output. Buil! 
in Cassette, 40 pin interface conn., 16K User RAM 
memory, Expandable to 48K. 

For more information, ploase call or writs. 



ATARI 



16K for /5I5J 
ATARI 800 

PERSONAL COMPUTER SYSTEM 

400 COMPUTER 479 

820 PRINTER I40 col. 1 459 

810 DISK DRIVE 559 

410 PROGRAM RECORDER 59 

815 DUAL DISK DRIVE 1199 

822 THERMAL PRINTER (40 col. 1 369 

825 PRINTER (80 col. imp. 1 795 

850 INTERFACE MODULE 175 

ATARI 16K RAM MODULE 155 

LIGHT PEN 65 

ACOUSTIC MODEM ICATI 169 

COMPUTER CHESS 35 

SPACE INVADERS 19 

STAR RAIDERS 49 

SUPER BREAKOUT 35 

3-D TIC-TAC-TOE 35 

VIDEO EASEL 35 

MUSIC COMPOSER 49 

VISICALC DISK 129 



OSI 



SCIENTIFIC 

C4P 
»799 

C4PIV 





PLOTTERS VIDEO MONITORS 




*1095 



only 
WATANABE MIPLOT 

tor more info please call or write 



LEEDEX VIDEO 100 139 

SANYO 9" B&W 165 

SANYO 12" B&W 255 

PANACOLOR 10" COLOR 329 

NEC 12" HI-RES COLOR 875 

NEC 12" LORES COLOR 399 

NEC 12" GREEN PHOSPHER(P3il . . 239 

TELEVIDEO 912B&C 698 

TELEVIDEO 920B & C 745 



Cassette Disk 

SPACE INVADERS 19 29 

SARGON II 30 35 

FORTH N/A 69 

OS 65-D V3.3 N/A 79 

MDMS PLANNER N/A 100 

GRAPHICS I N/A 35 

dac I N/A 45 

ASSEMBLER/EDITOR 40 N/A 

EXTENDED MONITOR 20 N/A 

PASCAL & FORTRAN (4P 6 8P only! . N/A 450 

When orderina Dlease SDGcifv system. 



PRINTERS 



ANADEX DP 8000 775 

ANADEX DP 9500 1350 

BASE 2 649 

CENTRONICS 737 825 

PAPER TIGER IDS-460 w/graphics 1195 

PAPER TIGER IDS-440 w/graphics 895 

NEC SPINWRITER 2550 

TRENDCOM 200 519 

SILENTYPE W/Int 515 

EPSON TX-80 w/graphica 729 

EPSON MX-80 132 col 620 

QUME SPRINT 5 2550 



ORDERING INFORMATION: Phone Orders invited using VISA. MASTERCARD, AMERICAN EXPRESS, or bank wire transfers VISA S MC credit card service charge of 2°» 
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us to send COD or on purchase orders or open account (please send for written quotation ) All equipment is subiect to price change and availability Equipment 
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PLEASE SEND ORDERS TO: 
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Circle 53 on Inquiry card. 



System Review 



The Sinclair Research ZX80 



John C McCallum, Department of Computer Science 

York University, 4700 Keele St 

Downsview, Ontario, M3J 1P3 Canada 



The new ZX80 microcomputer from Sinclair Research 
Ltd is a remarkable device. Although first announced to 
the North American public in February, 1980, the 
microcomputer did not become available until the fall. 
During the wait, the price has dropped from the expected 
$245 to just under $200. Because of this, the ZX80 is being 





Name 


Other hardware features 


Sinclair ZX80 


Forty-key pressure- 




sensitive keyboard; built- 


Manufacturer 


in RF (radio-frequency) 


Sinclair Research Ltd 


modulator (for channel 


475 Main St 


2); creates video display 


POB 3027 


of 24 lines of 32 


Wallingford CT 06492 


characters each; includes 


(617) 367-1988 


AC adapter, cables to 




cassette recorder 


Price 




$199.95 


Software 




4 K-byte system ROM, 


Dimensions 


which includes a BASIC 


15.9 by 20.8 by 3.7 cm 


interpreter and necessary 


(6Vi by 8Vz by V-A 


internal software 


inches) 






Options 


Processor 


8 K-byte BASIC module 


Z80A, 8-bit 


and 16 K-byte program- 




mable memory module 


System clock frequency 


(see "New Sinclair 


3.25 MHz 


Modules" text box for 




details) 


Memory 




1 K-byte static memory, 


Comments 


4 K-byte system ROM 


Contains introductory 


(includes BASIC inter- 


BASIC book, A Course 


preter) 


in BASIC Programming, 




128 pages, 20 by 14 cm 


Mass storage 


(8V4 by 5 3 /4 inches) 


Uses standard cassette 




recorder (not included) 





widely advertised as the first personal computer for 
under $200. 

The ZX80, shown in photo 1, is a new design from 
Clive Sinclair, a well-known British electronics in- 
novator. Sinclair is best known for his previous products: 
a miniature television, low-cost calculator and digital 
watch kits, and miniature stereo components. All of his 
products have stressed small size, low cost, and high- 
quality operation — usually at the expense of packaging. 
The same is true of the ZX80. 

Can it be any good if it sells for under $2007 This is a 
reasonable question, but the question that is most impor- 
tant when buying a computer is, "Will it do the job I want 
it to do?" The only way to tell is to look at its features in 
some detail. In order to design a very low-cost computer, 
some features had to be cut. However, the new features 
that have been added are rather impressive. The good 
features include low price, small size, high micropro- 
cessor speed, ease of program entry, and real-time BASIC 
syntax checking. 

The price of $199.95 includes the assembled computer, 
an AC (alternating current) power adapter, a cable to 
connect the ZX80 to a standard television set (channel 2), 
connectors for a cassette recorder, and a well-written 
book on programming in BASIC for the ZX80. For those 
interested in building kits, a kit version is available. 
However, you will not save money by doing so, and the 
kit involves some steps that are rather involved for an in- 
experienced kit builder. 

The ZX80 is small. The actual dimensions are 15.9 by 
20.8 by 3.5 cm (6V2 by 8V2 by IV2 inches), or about the 
size of a hardcover book. It is not the smallest personal 
computer — the new pocket computers from Sharp, Pana- 
sonic, Quasar, and Radio Shack have that honor. Also, 
because the ZX80 has to be attached to its AC adapter 
and a television set to work, some of its size advantage is 
lost. 

As part of this evaluation, several benchmark pro- 
grams were run in BASIC to compare the ZX80 to other 
personal computers. Although the ZX80 is not as fast as 
advertisements imply, it does run faster than many other 
personal computers, including the Radio Shack TRS-80 
Model I. 



94 January 1981 © BYTE Publications Inc 




"1 



'What You Don't Know 

Won't Hurt You". Couldn't Be 

Further From The Truth 

When It Comes To Running Your 

Own Business. 




How far from the truth is the 
adage that says "What you 
don't know won't hurt you." 

Systems II is designed to 
give you the advantage. Its up- 
dated methods and program- 
ming procedures will take you 
out of the "pencil pushing" age 
and into "today's technology". 
The Reasons For Systems II 

The number one reason 
is dependability. 

At Applewest Inc. we have 
put the system through its 
paces. However no matter how 
much "in-house" testing is 
done the true test comes from 
the end user — like yourself. 
We listened to our customers 
and we learned. 
Here Is What We Found Out 

The small businessman 
wants big performance from 
his micro system, not micro 
performance. He wants com- 
plete documentation that is 
easy to use. He wants com- 
plete flexibility to grow into a 



more advanced system. He diskettes, standard eight inch 
wants the availability of addi- disk or a ten megabyte hard 
tional programs so he won't be disk. Programs are continuous- 
boxed in. Last, but not least, he ly being developed to expand 
wants support for any pro- the usability of our system, 
blems he may have. See your local dealer today. 
Here Is How We Responded If he doesn't have SYSTEM II 
To expand the performance have him give us a call. 

Of the already Super Apple II, Systems II - Apple II - And You 

the KSAM (keyed sequential ac- Moving Your Business Forward 
cess method) was developed Faster. 

for fast aCCeSS tO any reCOrd 2455 s.W. 4th Ave., Suite 2, Ontario, Oregon 97914 

on file, giving performance that P03)88i-ii47 .^ 

even larger systems find hard ,- 

to beat. ^.tfrjpv 

Our documentation is the ^P^^f- 
most complete of any on the '-'-^ 
market. Our Operations Manual 
explains in depth the use of 
each module in the system, but 
we didn't stop there. 

A Lesson Manual/User's W&m 
Guide was developed =_ 

taking the user through — = = == ■= |s^ i , = ; f ! g= =r : | 

ted, learning process. = ==T~ 

SYSTEMS II is avail- SoFtUIOfC Inc. 

able On five and One quarter Apple ll is a trademark of Apple Computers 




High 
Technology 

Have you heard"? 
The Cashier* has been 
promoted to 
The Store Manager. 



The Cashier has so much more to offer 
than its name implies that we decided to 
give it a new name. This valuable software 
package can save time and increase profits 
for small business owners by providing: 

• real-time inventory control 

• point-of-sale functions 

• customer & vendor address lists and 
mailing labels 

• informative management reports 

• up-to-the-minute sales monitoring 

• invoices, quotations, & packing slips 

• purchase orders & receiving reports 

• daily, monthly, and year-to-date sales totals 

• physical inventory checklists 

• and much, much more. 

But what can you call a software package 
for the Apple II* that does so much? You 
might call it 'remarkable' ... we call it 
The Store Manager. 

Drop by your local 
computer store and 
see what The 
Store Manager 
can do 
for you. 




High 
Technology, Inc. 

P.O. Box B-14665 
8001 N. Classen Blvd. 
Oklahoma City. Oklahoma 73113 
405 840-9900 



•Apple II and The Cashier are trade names ol Apple Computer Inc 




Photo 1: A photograph of the ZX80 in operation. The 
homemade power supply gives an indication of the small size of 
the computer. At the bottom of the television set, a BASIC line 
is being edited. 



The ZX80 also has a few software features that are 
useful. The single-keystroke keywords mean that, instead 
of typing a whole word, you have to type only a single 
character on the keyboard. This can cause some confu- 
sion at first, and it takes some time to remember not to 
type the whole word. But it does speed up the typing pro- 
cess when entering a program. Because the keywords are 
stored in 1 byte each, you save memory space that can be 
used for extra program storage. 

Another BASIC feature that I found impressive is the 
syntax checking of the program as you type it in. 1 have 
always been disappointed that most other versions of 
BASIC do not do this. The ZX80 actually prompts you 
with the type of input it is looking for — a keyword, a 
literal, a string, or a number. If you enter an illegal state- 
ment, it indicates where the statement is wrong and will 
not let you enter that statement into the program. It also 
does a similar check on input data requested by a running 
BASIC program. In fact, it allows you to enter simple ex- 
pressions for numeric input and calculates the value while 
reading the value into the program; a very nice feature. 

At $200, though, everything cannot be optimum. 
There are objectionable features too. The most annoying 
or limiting features of the ZX80 are its small memory 
size, screen blanking during program execution, its 
limited BASIC, and its keyboard. 

The ZX80 comes with 1 K bytes of programmable 
static memory, although a memory-expansion board 
allowing 16 K bytes of memory is expected soon (see text 
box). These 1024 bytes of memory are shared by system 
variables, your BASIC program, the program variables, 
working space, the video-display memory and the stack. 
Although the space is used very efficiently, 1 K bytes of 
memory do not store a large program, no matter how 
efficiently it is squeezed. 

Perhaps the most limiting characteristic of the ZX80 is 
the screen-blanking behavior. When the ZX80 is ex- 
ecuting a program, the TV screen goes black. This hap- 
pens because the processor is used to control the display 
as well as to do the processing, and the design decision 
was made to have the processor devote its time to only 
one of these. The effect of this trade-off is to increase pro- 



Circle 54 on inquiry card. 



Circle 55 on inquiry card. 



H 



■mi 



dalasoulh announces. •• 

THE TOTAL PRINTER PACKAGE! 




! 




With so many matrix printers on the market today, it may seem 
tough to find exactly the right one for your application. Some 
models may offer the speed you need, others the communications 
flexibility and still others the forms handling capability. But no 
printer offers all the features you need... until now. 
The DS180 matrix printer provides the total package of perfor- 
mance features and reliability required for applications such as 
CRT slave copy, remote terminal networks and small to mid-range 
systems. Not a "hobby-grade" printer, the DS180 is a real work- 
horse designed to handle your most demanding printer require- 
ments. And pricing on the DS180 is hundreds of dollars below 
competitive units. 

High Speed Printing -Bidirectional, logic-seeking printing at 
180 cps offers throughput of over 200 Ipm on average text. A 
9-wire printhead life-tested at 650 million characters generates 
a 9x7 matrix with true lower case descenders and underlining. 
Non-volatile Format Retention -a unique programming keypad 
featuring a non-volatile memory allows the user to configure the 
DS180 for virtually any application. Top of form, horizontal and 
vertical tabs, perforation skipover, communications parameters 



and many other features may be programmed and stored from the 
keypad.When your system is powered down/the format is retained 
in memory. The DS180 even remembers the line where you stopped 
printing. There is no need to reset the top of form, margins, baud 
rate, etc. . . . it's all stored in the memory. If you need to recon- 
figure for another application, simply load a new format into the 
memory. 

Communications Versatility -The DS180 offers three interfaces 
including RS232, current loop and 8-bit parallel. Baud rates from 
110-9600 may be selected. A 1K buffer and X-on, X-off hand- 
shaking ensure optimum throughput. 

Forms Handling Flexibility -Adjustable tractors accommodate 
forms from 3"-15". The adjustable head can print 6-part forms 
crisply and clearly making the DS180 ideal for printing multipart 
invoices and shipping documents. Forms can be fed from the front 
or the bottom. 

If you would like more information on how the DS180's low-cost 
total printer package can fill your application, give us a call at 
Datasouth. The DS180 is available for 30-day delivery from our 
sales/service distributors throughout the U.S. 

data©®* 

computer corporation 



4740 Dwight Evans Road • Charlotte, North Carolina 28210 • 704/523-8500 



2a 



1 REM 

S REM CKhRRCTER SET 

3 PRINT " " 

4. PRINT " " 

SSPRINT - " 

lO FOR 1 = 1 TO 2SS 

20 PRINT CHR* 1 1 ) ; 

30 NEXT I 



- ZXSO 



fa 



2b I 



1 



j"£J% ■J»»*£$:?<l-+X>'=><; , .01S345 
e.TQgflSCOEFGHIOKUMNOPORSTUVWXYZ?? 




THEN TO ; , ) C 

NOT -*X/ AND OR XI=>< LIST RETU 

RN CLS DIM SRVE FOR GO TO POKE I 

NPUT RhNDOMISE LET •?? NEXT PRINT 

? NEW RON STOP CONTINUE IF GO S 

U8 LORD CLERR REM f 



0/30 



Photo 2: The character set of the ZX80 computer. Photo 2a 
shows a program that will list all 256 characters used by the 
ZX80. Photo 2b shows the character set produced by the pro- 
gram; note that some characters are expanded to multiletter 
keywords and that undefined codes are represented by a ques- 
tion mark. 



cessing speed at the expense of limiting the interactive 
quality of the ZX80. It is not going to have the same types 
of games as the Commodore PET or the Apple II com- 
puters. However, when performing long calculations on 
the ZX80, it is easy to tell when the program ends — the 
room bursts into light! 

The limited features of ZX80 BASIC are also 
frustrating. This is a result of the limited amount (4 K 
bytes) of ROM (read-only memory) available. This mem- 
ory contains the software used for the BASIC interpreter, 
for the character generator for the TV display, for de- 
coding the keyboard, and for cassette reading and writ- 
ing. This squeeze results in many useful BASIC functions 
being omitted. 

When dealing with strings, for example, you can break 
up a string using two functions: CODE gives the ASCII 
(American Standard Code for Information Interchange) 
equivalent of the first character of the string; the TL$ 
(tail) function returns a string containing all but the first 
character of the string. As an example of functions left 
out, you cannot put two strings together (no concatenate 
operation or function exists). However, Sinclair intends 
to bring out an optional 8 K-byte floating-point BASIC 
on a single ROM. With more than double the space to 
work with, it should be a very rich and impressive 
language. 

The last feature that I find annoying is the keyboard. It 
works — but @"#$. It is a touch-sensitive key- 
board — smooth, washable, indestructible. But it is dif- 
ficult to keep your fingers positioned properly on the 
keys, particularly on the shift key, without inadvertently 
pressing an extra key or two. The hardest keys to use are 
the cursor controls and the rubout keys (both are shifted 
characters). I always seem to end up with zeros where I 
want to remove a character (rubout is shift-zero). Re- 
member, though, that some people pay more for a key- 
board than this entire computer costs. This was a very 
wise place to save money on the design. 



iOO REM BENCHMRRK PROGRfiM 7 

SOO PRINT "START " 

AOO LET K=0 

<K30 DIM M(S) 

500 LET K=K+1 

51CHLET R=Kvax3+*-5 

520 GO SUB 820 

5GO FOR l_=l TO S 

SOS LET M(L)=R 

SAO NEXT L 

BOO IF - K<1000 THEN GO TO SOO 

VOO PRINT "END" 

SOO STOP 

820 RETURN 



510 LET BR=K/ , axa-»*-s 



Photo 3: Editing on the ZX80. The cursor (at line 510 at the top 
of the screen) can be moved via arrow keys to different lines of 
the program. When the Edit key is pressed, the line being 
pointed to is copied at the bottom of the screen, where it can be 
edited. The cursor on the bottom line can be moved right and 
left; characters can be deleted or inserted at the current cursor 
position. When the Newline key is pressed, changes made in this 
line are added to the existing program. 



Some Technical Details 

The ZX80 microcomputer uses a very efficient design 
with a total of only twenty-two standard integrated cir- 
cuits, including the voltage regulator. The main pro- 
cessor is a Z80A processor running at a speed of about 
3.2 MHz. The programmable memory is a pair of 4 K-bit 
static memory devices. The ROM is a single 4 K-byte 
part that includes both the BASIC interpreter and the 
other functions listed above. 

The operation of the ZX80 is — so far as I understand 
it — quite complicated because it works on a mix of hard- 
ware and software. The overall concept is that the refresh 
counter of the Z80 is used to control the generation of the 
lines of the video display, producing dots on the TV 
screen at twice the frequency of the processor clock. The 
keyboard is scanned under software control as I/O (in- 
put/output) port number 1, a port that is also shared by 
the cassette input circuitry. The cassette output signal is 
the same as the video synchronization signal; it is also 
under software control. It is an interesting design, but 
you will need to study the ZX80 ROM carefully before 
you can really understand it. 

The character set is also a little strange. The keywords 
that are entered with single strokes are stored as single 
tokens and are expanded when displayed. Photo 2 shows 



98 January 1981 © BYTE Publications Inc 




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BYTE January 1981 99 



a program for generating all 256 codes. 

The high quality of the black-and-white display can be 
seen in the photograph of the TV screen, which is a stan- 
dard 12-inch color TV set (see photo 2b). The question 
marks are undefined codes, and the keywords (which are 
spelled out) are fairly obvious. The graphics characters 
allow a limited 46- by 64-pixel graphics resolution. 
However, since the ZX80 is not primarily designed for in- 
teractive graphics applications, the existing resolution on 
the ZX80 should be sufficient. 

Software Features 

The ZX80 system is excellent for learning introductory 
programming concepts. This is in large part due to the 
immediate feedback about errors. For the student at the 
introductory level, the limited features of the language 
are useful in preventing confusion; compare this with the 
extreme detail taken to describe some complicated ver- 
sions of BASIC. When you are ready to progress at a 
later time, the expanded version of BASIC will be 
available. 

ZX80 BASIC not only prevents you from making syn- 
tax errors, but it also prompts you with a cursor that tells 
you what it is expecting — a keyword (denoted by a K in- 
side the square cursor) a literal (denoted by an L), or a 
numeric literal (denoted by an LS). When a program is 
expecting string input, it puts the cursor between quotes, 
then expands the quotes as you enter the text. With the 
ZX80, you never get the string errors during data entry 
that are so common with other personal computers. 

The method of editing programs is also well planned. 
A cursor, controlled by the t and I cursor keys, is used to 



text. 


Sine 


e lines 


nre 


octer 


, words, lin 


» or 


anywr 




n the 


text 


opens 


up 


or clos 


s as 


rioge 


retu 


ns as 


well 


since 


each 


line of 


tex 



the electric pencil II 

% for the TRS-80 Model II* Computer 

OEM 

The Electric Pencil is o Character Oriented Word Processing 

System. This means that lex! is entered as a conlinuous siring 
of characters aid is manipulated as such. This allows the user 
enormous freedom and ease in the movement and handling of 
not delineated, any number of char- 
' paragraphs may be inserted or deleted 
. The entirety of I he text shifts and 
; needed in full view of the user. Cor- 
as word hyphenation arc not requi red 
t is formatted automatical ly. 

As text is typed and (he end of o screen line Is reached, a 
portiolly completed word is shifted to the beginning of the 
following line. Whenever lext is inserted or deleted, existing 
lext is pushed down or pulled up in a wrap around fashion. 
Kverylhing appears on the video display screen as it occurs 
(hereby eliminating any guesswork. Text may be reviewed ot 
will by variable speed or page-at-o-time scrolling both in the 
forward aid reverse directions. By using the search or the 
search and replace function, ony string of characters may be 
localed rnd/or replaced with any other string of characters as 
desired. Specific sets of characters within encoded strings 
may also be located. 

When text is printed, The Electric Pencil automatically 
inserts carriage returns where they are needed. Numerous 
combinations of Line Length, Page Length, Character Spacing, 
Line Spacing end Page Spocing allow for any form to be 
handled. Right justification gives right-hand margins that 
are even. Pages may be numbered as well as titled. 

the electric pencil 



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1-lrmb.T Tally * Global Search & Replace • Full Margin 
Control • End of Page Control ■ lion Printing Text 
Commenting * Line & Paragraph Indentation ■ 
Centering • Underlining • Boldface 



The Electric Pencil I is still available for TRS-80 Mode! I 
users. Although not as sophisticated as Electric Pencil II, it 
is still an extremely easy to use and powerful word processing 
system. The software lias been designed to be used with both 
Level I (I6K system) and Level II models of lite TRS-80. Two 

are available an cassette. The TRS-80 disk version is easily 
transferred to disk end is fully interactive with the READ, 
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point to the "current" line. When the Edit key is pressed, 
the current line moves down to the bottom of the screen 
to the program-entry line. There is always at least one 
line between the program and the text-entry line, so you 
will not get the areas confused. 

Once the line is in the program-entry area, the line is 
treated exactly like a program line that you are typing ex- 
cept that the cursor is at the beginning of the statement. 
The cursor control keys — and -* are used to move the 
cursor within the line. Typing anything just inserts it at 
that point in the line, and the rubout key is used to delete 
the previous character. When you are finished editing, 
just press Newline and the edited line replaces the old line 
in the program (see photo 3). If you modify the line 
number during editing, you create a new line in the pro- 
gram. This feature makes it very easy to duplicate lines in 
a program. 

The best way to describe the features of the ZX80 
BASIC language is to add to the comparison table used 
by Creative Computing in their "BASICs Comparison 
Chart" (July 1980 issue, pages 28 and 29). The major 
features of the Sinclair Research ZX80 4 K-byte BASIC 
are given in table 1. 

Performance of the ZX80 

At some time, all users become concerned about the 
speed of their computers. There is no simple way to com- 
pare the speed of various personal computers without 
running actual programs. Two standard benchmarks 
have been used to compare a wide range of computers 
running BASIC. These have been run on the ZX80 to get 
a valid estimate of its speed. 

The system clock frequency of the Z80A processor is 
3.2 MHz. This compares to about 1.77 MHz for the 
Radio Shack TRS-80 Model I or to the 4 MHz of the 
TRS-80 Model II, both of which also use the Z80 as the 
main processor. A Z80 running at 2 MHz should be 



Integer variables 


yes; names must contain letters and 




numbers only, but can be any length. 


Real variables 


no 


String variables 


yes; names must be one letter fol- 




lowed by a dollar sign (eg: AS, B$, ..., 




Y$, Z$). 


Arrays 


integer and one-dimensional (eg: 




C(N)) only; names must be one letter 




long and are initialized to zero 




values. 


Arithmetic operations 


performed on 16-bit signed integer 




values. 


Arithmetic operations 


+ ,-,*,/,** (exponentiation) 


Relational operations 


= ,>,<, on either string or integer 




argument pairs. 


Boolean operations 


NOT , AND , OR performed on cor- 




responding bits of integer arguments. 


String operations 


CHR$(X), TL$(X$), STR$(X$) 


BASIC statements 


CLEAR, CLS, DIM, FOR, GOSUB, GO 




TO, HOME, IF, INPUT, LET, NEXT, 




POKE, PRINT, RANDOMIZE, REM, 




RETURN, STOP 


BASIC expressions 


ABS(X), CODE(X$), PEEK(X), RND(X), 




USR(X) 


BASIC commands 


CONTINUE, EDIT, LIST, LOAD, NEW, 




RUN, SAVE 


Graphics 


20 graphics characters; effective 




resolution is 46 rows of 64 squares 




per row, plus some graphics 




characters for shading. 


Table 1: Summary of the Sinclair Research ZX80 4 K-byte 


BASIC. 





100 January 1981 © BYTE Publications Inc 



Circle 57 on inquiry card. 



WHYCIS COBOL 

LETS TOUR 

MICROCOMPUTER 

PERFORM LIKE A 



MAINF 



Now, you can use a microcomputer for 
sophisticated business applications 
. . . because now there's CIS COBOL. 
Micro Focus developed this COBOL so 
your microcomputer can run the same 
programs as a minicomputer or a 
mainframe. 

CIS COBOL is Micro Focus' Compact, 
Interactive, Standard COBOL which 
offers the advantages of COBOL . . . 
powerful data structure features, English- 
like language, existing programmer 
expertise ... to provide you with a full 
commercial language. You won't be 
restricted by size either: a 64K byte 
microcomputer will compile up to 8000 
lines of COBOL, more if the program's 
split into dynamically loaded modules. 

Choose a Compact Compiler. 

The Compact compiler runs on 32K byte 
microcomputer systems. Its powerful 
subset includes full support for random, 
indexed and sequential files. 

Or choose the 
Standard Compiler. 

The Standard CIS COBOL compiler 
requires a minimum 48K of user RAM. 
A super-set of the Compact compiler, 
implementing ANSI 74 COBOL to 
Federal Low-intermediate Level. 



The same CIS COBOL 
extensions for conversational 
working, screen control, interactive 
debugging, and special peripheral sup 
port are in both compilers. And there are 
more reasons to consider CIS COBOL: 

• It conforms fully to the ANSI 74 stand- 
ard, so programs are portable upwards 
and downwards to minis or mainframes. 

• Its interactive features enable main- 
frame programmers to get results fast . . . 
workingon inexpensive microcomputers. 

Forms 

The FORMS utility lets you build a 
screen layout online at the CRT. Then 
it automatically generates COBOL 
record descriptions for inclusion in your 
program. 

Forms-2 

A superset of FORMS, it eliminates the 
need to write simple data entry and 
inquiry programs, because the programs 
can be automatically generated from 
screen definitions. 

Environment 

CIS COBOL products run on the 8080 
or Z80 microprocessors under the CP/M* 
operating system, and on the LSI-11 
or PDP-11 processors under RT-11. 
They are distributed in a variety of disk 
formats and come with a utility that 
enables you to use any make of CRT. 

OEMs 

Intel has adopted CIS COBOL and offers 
it (as iCIS-COBOL) for their Intellec and 




Intellec II systems. Ideal 
for OEM's or private label, 
CIS COBOL was developed 
"entirely by Micro Focus. Send 
inquiries for CIS COBOL object packs 
and application vendor terms to MICRO 
FOCUS or its licensed distributors. 
Distributor terms also available from 
MICRO FOCUS. 
______________^ 

Send me more information for: bi I 

□ Single Copy Users 

□ Reseller and Distributor Licensing 

Name 

Title 

Company 

Address 



City/State 

Zip/Phone 

Computer Model. 
Version of DOS_ 



MICRO FOCUS 

Micro Focus Inc. ■ 1601 Civic Center Drive • 
Santa Clara • CA 95050 • Tel: (408) 984-6961 • 
Telex: 171-135 MISSION SNTA 

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CIS COBOL distributors include: Vector Graphic, Onyx Systems. Altos Computer Systems. Lifeboat Associates. Research Machines, Telecomputing, Modular Business Systems. Rair, Midlectron. 
Roslronics and Johnson-Laird Inc. tlntellec is a trademark of Intel Corp. *CP/M is a trademark of Digital Research Inc. 



Circle 58 on inquiry card. 



BYTE January 1981 



101 



Benchmark 

Number 12 3 4 5 6 7 

Execution 

Time (Seconds) 1.6 4.7 9.0 8.5 12.2 25.3 38.5 



Table 2: Execution times of BASIC benchmark programs on 
the Sinclair ZX80. See text for details 



similar in speed to a 6502 running at 1 MHz (as used in 
the Commodore PET or the Apple II). These estimations, 
however, do not consider the efficiency of the BASIC in- 
terpreter, which is often the most important speed factor. 
Thus, the execution-timing test of actual BASIC bench- 
mark programs is the most important way of comparing 
the speed of various personal computers. 

The ZX80 ranked between second and third places in 
the BASIC benchmarks done for Kilobaud magazine (see 
"BASIC Timing Comparisons" by Tom Rugg and Phil 
Feldman, October 1977, page 20). It was beaten only by a 
6502 microprocessor running at 2 MHz (an Ohio Scien- 
tific Challenger II running its 8 K-byte BASIC), and by a 
Z80 running at 4 MHz (Zapple 8 K-byte BASIC). For 
those interested in the actual times of the benchmark pro- 
grams, they are given in table 2. 

The prime-number program used for benchmarking 
BASIC processors by Interface Age was also run (see 
"Assignment: Benchmark," by Tom Fox, June 1980, page 
130). [A similar benchmark program was given in 
"TRS-80 Performance: Evaluation by Program Timing" 
by James R Lewis, on page 84 of the March 1980 
BYTE....GW] This benchmark is particularly interesting 
because it was run on several of the fastest small com- 
puters, as well as on a DEC (Digital Equipment Corpora- 
tion) PDP-10 computer. The program given in the Inter- 
face Age article had to be modified slightly to allow for 
integer BASIC. However, the only major effect was to 
change an INT function to an integer multiply. The ex- 
ecution time for the program running on the ZX80 was 



1604 seconds. Although this was not very fast compared 
with many of the computers in this benchmark, it was 
not the slowest either (the TRS-80 Model I took 1928 
seconds). The execution time was decreased to 1513 
seconds by removing the comment statements from the 
program (a 5 % increase in speed) . This is a typical way of 
speeding up BASIC interpreters. 

The ZX80 might be summarized as a high-perfor- 
mance, very low-cost, portable personal computer sys- 
tem. It is best used for home or school use in learning the 
concepts of programming. When the memory-expansion 
and floating-point-BASIC modules become available (see 
the "New Sinclair Modules" text box), it will also be good 
for low-cost mathematical, scientific, and engineering ap- 
plications. If you are looking for your own home com- 
puter, the ZX80 is a good starting point. ■ 



New Sinclair Modules 

As this article goes to press, Sinclair Research Ltd 
has announced two new modules for the ZX80, an 
8 K-byte BASIC in ROM and a 16 K-byte program- 
mable-memory module. According to an American 
representative of Sinclair Research Ltd, the pro- 
grammable-memory module and a later version of the 
BASIC module currently being sold in England will 
probably be available soon on the American market. 
The prices are expected to be "under $100" for the 
16 K-byte programmable-memory module and "about 
$40" for the 8 K-byte BASIC module. The BASIC 
module will be slightly different from the one now be- 
ing sold in England in that it will add printer support 
to the ZX80. 



-ZX80 



References 

1. Davenport, Hugo. A Course in BASIC Programming- 
Operating Manual. Sinclair Research Ltd, 1980. 

2. "Personal computer looks to open up the market with an ultralow 
price." Electronics, Volume 54, Number 4, February 14, 1980, pages 
80 thru 82. 




1 Trademark of Western Digital. ; -j 
'Trademark of Digital Research.;'; "■' 
'Trademark of University of Caljrbttiiili : 



Copyright ©1980. 
Digicomp Research 
All rights reserved. 



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102 January 1981 © BYTE Publications Inc 



Circle 59 on inquiry card. 



Don't play games 
with your company's money. 




Our entry level computer system is the first step in 
a full range of computer products. Not the last step in 
a full range of computer games. 

We call it VIP. The Vector Intelligent Partner. And 
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for your money. 

VIP has all the assets and none of the liabilities of 
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For information contact Vector, 31364 Via Colinas, 
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Economy Sized Computers 



Circle 60 on inquiry card. 



BYTE January 1981 103 



Education Forum 



Multi-Micro Learning 
Environments: 

A Preliminary Report on the 
Solo /NET /works Project 



Dr Thomas A Dwyer, Soloworks Laboratory, 

University of Pittsburgh, Department of Computer Science, 

Pittsburgh PA 15260 



Inventive Learning 

It's a good idea to "back off" occasionally from the 
tough problems of education in the real-school world 
and spend some time thinking about what it would take 
to develop learning systems that go beyond training in 
the basics. In particular, it is valuable to contemplate the 
intricacies of some of the impressive natural-learning 
phenomena that surround us. For example, when a two- 
year-old child startles her parents by speaking an adult- 
sounding sentence (one recently heard was, "No garage 
sales today — that's ridiculous") it's worth contemplating 
the significance of such a minor miracle as a key to 
understanding later cognitive developments. In a similar 
manner, when a six-year-old masters the "solution" to a 
complex system of differential equations in the eminently 
practical form of learning to ride a bicycle, we should 
spend more than a few moments asking what made such 
a remarkable conquest possible. 

An examination of these and similar examples of com- 
plex human learning reveals that in addition to the intrin- 
sic (and still quite mysterious) human potential for 
developing an ever expanding "life of the mind," there are 
two important external elements at work. These elements 
can be described as supportive-social and supportive- 
physical environments. In the case of the loquacious two- 
year-old quoted above, the supportive-social environ- 
ment was the constant flow of conversation between 
parents and child as they made their rounds of local 
garage sales in search of fun bargains. The supportive- 
physical environment was the set of real places that were 
visited as the child took part in the fascinating process of 
finding and acquiring some well-remembered objects, in- 
cluding, of course, a few toys. 

The learning-to-ride-a-bicycle phenomenon is sup- 
ported from the same two bases. The social environment 
is the neighborhood full of other kids who can handle a 
two-wheeler and the fun that is promised to anyone who 
can participate in the local rites of pedal-pushing. The 
physical environment is the pavement on which to pedal 
and of course the bicycle. When similar examples con- 
nected with older students are analyzed (eg: learning to 
fly an airplane solo in 10 hours), it is evident that the 




Photo 1: Students from a local high school learn to play N-Trek. 
The terminals being used were connected to a PDP-11 RSTS 
time-sharing system, with each terminal controlling a job 
related to a function of one starship crew member. The jobs in- 
teracted through use of shared variables in a common segment 
of memory. 



heritage of ideas built into complex mechanisms is often a 
crucial part of supportive-learning environments. 

It was another example of such environmentally sup- 
ported human learning that triggered the idea behind the 
Solo/NET/works project. The example came out of 
something called the Soloworks project in the mid 1970s. 
The Soloworks project involved the use of computer 
technology to support a complex multiplayer version of 
the popular game Star Trek. (See photo 1.) Written by 
student Don Simon, the game was nicknamed N-Trek. 
This was because it allowed a variable number of players 
to interact in a cooperative simulation /game setting. 

In its original version, N-Trek was run on a PDP-11 
minicomputer time-sharing system. The general idea of 
the game was similar to more conventional versions, with 
the starship Enterprise commissioned to explore the 
unknown while doing battle with the evil Klingon forces. 
The big difference was that in N-Trek, the Enterprise real- 
ly was run by a crew. Each member of this crew manned 
a terminal on the computer system, and depending on 
how the game was initialized, each crew member played 
a specific role. Thus, one terminal was run by the com- 
mander of the ship, another was manned by the weapons 
officer, a third was dedicated to navigational tasks, and 
so on. A separate graphics display showed the various 
sector maps and status tables of the game, while an added 
element of feedback was provided by a colored light dis- 
play and a voice synthesizer that intoned such messages 
as "RED ALERT" or "SHIELDS UP." 

All in all, the many dramatic sessions played on this 
system were rated as some of the best examples of en- 
vironmentally supported learning that took place during 
the project. The word learning is used here with delibera- 
tion. The rules for handling the various roles in N-Trek 



104 January 1981 © BYTE Publications lnc 



Circle 61 on inquiry card. 



COMPARE FLEXIBILITY. 



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Education Forum 




Photo 2: The equipment currently available in the Solo/NET/works laboratory. The terminal at the lower left in Photo 2a is used for 
the WAG display (as explained in the text). To its right is the IMSAI S-100 computer that emulates the unrooted-tree network and 
performs the managerial WAG functions. Further to the right are the system console and bus-status monitor; the other micropro- 
cessors operate as nodes in the network. Photo 2b shows MATSRCH designer Ivan Zatkovitch using an Apple II computer in a ver- 
sion of the game that requires only one player. 



were extremely complex, yet it was possible to bring in a 
group of neophytes and have them playing well in very 
short order. The most remarkable thing about this learn- 
ing was that it took place with surprisingly little explana- 
tion time; it happened mostly as a result of doing what- 
ever was necessary to handle the task at hand. It was also 
a form of learning that prompted students to develop new 
strategies and theories. It was, to use a phrase we later 
coined as being particularly appropriate, inventive learn- 
ing. 

The Generalization of N-Trek 

The new Solo/NET/works project (which like its 
predecessor is supported in part by the National Science 
Foundation Development in Science Education program) 
can be looked upon as an extension and generalization of 
the N-Trek experience. The goal of the project is to 
develop a prototype learning environment that will sup- 
port a variety of multiprocess simulations. 

Physically, the environment will consist of a room (or 
several rooms) in which there is a variety of microcom- 
puters interconnected via a loosely coupled network. The 
phrase loosely coupled is used in two senses. Technically, 
it means that the microcomputers in the network have in- 
dependent (and very likely differently designed) system 
buses, and that they do not share memory. Pedagogical- 
ly, it is used to mean that each microcomputer node will 
be running an independent program (ie: process) that 
uses its own independent memory. The node processes 
will be able to cooperate, but only in ways determined by 
the program designers, and only via data communicated 
over the network. 

The reason we have kept the prefix Solo in the project 
name is to emphasize that the student controlling a given 
process (which may or may not have been designed by 
that student) is in charge of that aspect of the overall 
simulation. The sharing of data and the choice of which 
processes are to be cooperative is to be a student-team 
decision, and modifications of this decision will be 



viewed as an integral part of the learning process. We 
want the student activities to mirror the team efforts of 
professional scientific and engineering projects, but with 
strong emphasis on independent thought within a group 
effort. 

Educational Applications 

The tasks we have set in the first phase of the project 
(1980 thru 1982) are technical in nature. The first issue we 
must address is that of finding simple ways to intercon- 
nect low-cost hardware in a cooperative network setting. 
For this reason, it is premature to talk about applications. 
Of course, they will eventually be the most important 
aspect of the project. 

Our approach to applications in this first phase has 
been to outline scenarios describing how the system 
might be used, but to do most of our initial network 
testing with simplified surrogate applications (an example 
will soon follow). The purpose of the scenarios is to help 
us verify the accuracy and workability of the various 
system hardware and software decisions that must be 
made right away, while helping point the way to the best 
use of new technology sure to be available by 1982 and 
beyond. 

One example of a scenario we have found useful is 
based on the use of the Solo/NET/works system to 
model both realistic and futuristic air traffic-control 
systems. In this application, some students will play the 
role of pilots flying a variety of aircraft. Each student 
will control a microcomputer at a node of the network. 
The principal process running in the computer at one 
node will be a program that simulates the flight 
characteristics of a given (or imagined) aircraft. The 
other microcomputer nodes will be manned by air-traffic 
controllers. The principal process running at each of 
these nodes will be one that interprets data returned from 
aircraft transponders (a transponder is an "encoded" 
transmitter located in an aircraft), along with data on the 
position of ground-based navigational aids. 



106 January 1981 © BYTE Publications Inc 



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Education Forum 



There will also be a distinguished node in the network 
which we call the WAG (Weltanschauung, or "world 
view," Generator). This will calculate all the data needed 
to generate a graphic display of the total universe within 
which these pilots and controllers function. Normally, 
the total WAG display will be visible only to observers or 
visitors who are not engaged in the simulation. However, 
windows on this universe appropriate to the functions at 
specific nodes will be available to these nodes. For exam- 
ple, an air-traffic controller will be given a graphic 
display of the aircraft in the specific sector he controls. 
This corresponds to the way in which radar displays are 
actually used today. 

What will be learned by students working in such an 
environment? Specific learning will be in the areas of 
aerodynamics, navigation and geometry, piloting, and 
air-traffic control (for those so inclined vocationally). 
Also involved are large-system design, distributed com- 
puting, data-base design, and, of course, the physics and 
mathematics of Newtonian dynamics. 

The Solo philosophy assumes that students will play an 
active role in the design and modification of the programs 
for the node processes. More importantly, we believe 
that the participants who design, develop, debug, and use 
such a system will learn to be inventive — to devise 
strategies and procedures that transcend anything that 
even the best teacher or text could hope to transmit. 

The ultimate power of a multi-micro network is found 
in the fact that all the processes are run on general- 
purpose computers. This means that entirely new ap- 
plications, and an entirely new set of challenges to be in- 
ventive, are only as far away as the imaginations of the 
users. We have found that visitors often suggest in- 
genious examples of such applications and that these 
represent a multitude of disciplines. Some of the other 
scenarios that we are working on as a result of such 
discussions are in the areas of corporate-business 
management, computer-operating systems, economic 
models, the colonization of space, and models of human 
physiology that could be used in medical education. 

Network-Architecture Considerations 

The subject of computer networking is extensive, and a 
substantial amount of literature detailing a variety of ap- 
proaches has developed over the years. For our purposes, 
with our constraint to work with low-cost, off-the-shelf 
microcomputers, most of the options discussed in the 
literature were not directly applicable. It also became 
clear that, as with any new development, the promises of 
what could be done tended to be ahead of the availability 
of actual products. However, we spent some time think- 
ing through the consequences of trying to apply the most 
recent ideas about local-area networking to our applica- 
tion, subject to the constraint that costs had to be 
minuscule compared to those associated with the com- 
mercial and scientific networks in use today. 

We decided that even with this constraint, it would be 
advantageous to work conceptually with the unrooted- 
tree passive-bus configuration, considered one of the 
most powerful local-network architectures. Another 
name for this arrangement is the global multiple-access 

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Education Forum 



bus. Recent applications of this architecture are the Xerox 
Company's Ethernet, and the Ungermann-Bass Net/One 
system. 

Figure 1 gives a brief summary of some of the network 
architectures in use today. Although the passive-bus con- 
figuration appears to lack the complexity of the others, it 
is in reality a very general arrangement. This is because 
the bus (the heavy horizontal line) is assumed to be a 
wideband communications medium (usually a coaxial 
cable) to which any node can be connected by means of a 
transceiver. The transceiver contains sophisticated cir- 
cuitry that allows the nodes to contend for access to other 
nodes without waiting for their turn in a polling scheme. 
This circuitry also allows for flexible addressing schemes 
that allow the access paths in the network to be con- 
figured in any way desired. Logically, this configuration 
is equivalent to a fully connected distributed system, with 
no limitations or dependencies on which nodes are to act 
as control centers. 

Since it is not yet possible to buy low-cost bus hard- 
ware such as transceivers off-the-shelf for use with the 
popular microcomputers, we are simulating the passive 
bus-architecture with an S-100 microcomputer. The other 
node microcomputers in the network connect to standard 
serial I/O (input/output) ports on the S-100 machine. 
The idea is to have a program segment running in the 
S-100 computer that makes these ports appear to be 
"taps" onto a passive bus. Actually, all communications 
from the nodes will be via RS-232C ports which are 
available at a low cost. In the spirit of limiting costs even 
further, we are experimenting with having the same S-100 
computer also act as one of the nodes. 

Hardware and Software 

There are many ways to put together a system that acts 
like a general microcomputer network. One approach 
would be to use a single machine running a sophisticated 
operating system like UNIX (a development of the Bell 
System Laboratories), which allows the various users on 
the system to set up "pipelines" with each other. Bill 
Gates of Microsoft has indicated that they will soon have 
such a system for use on the newer 16-bit microcom- 
puters. This product will undoubtedly be worth in- 
vestigating when it becomes available. 

Two other products we considered were the Nestar 
system and the Corvus Constellation system. The Nestar 
system is designed specifically for Apple computers and 
the Apple II bus. The Corvus system was not in use any- 
where that we could visit. Although both these products 
are ingenious developments, we felt that with the lack of 
generality and experience with their use, it would not be 
wise to acquire the Corvus and Nestar systems at this 
time. This decision was further supported by our 
equipment-budget limitations and our desire to test the 
feasibility of using a variety of low-cost microcomputers 
as network nodes. Once we have a better feel for the 
capabilities of the various machines, we will not be hesi- 
tant in choosing the models that perform the best for us. 
It is pretty clear that trying to accommodate all the dif- 
ferences found in the various brands of microcomputers 
today can create lots of problems. 



110 January 1981 © BYTE Publications Inc 



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BYTE January 1981 111 



Education Forum 



BUS (UNROOTED TREE) 










DISTRIBUTED, MINIMALLY CONNECTED (RING) 





CENTRALIZED 




DISTRIBUTED, FULLY CONNECTED 




DECENTRALIZED 



HIERARCHICAL (TREE) 





Figure 1: Examples of network architecture. A network consists of nodes that are linked through communications channels. In these 
diagrams, square boxes represent nodes that act as resources in the network, circles represent users of these resources, and diamonds 
show devices or persons that act as intermediaries (buffers, terminals, displays, etc). The letters P and C indicate that the node is a 
person or a computer; a blank node means that the nature of the node is not specified. 



Fortunately, the lack of standardization is not as severe 
a problem with microcomputer languages and operating 
systems, and we had no misgivings about using Microsoft 
BASIC running under CP/M in the S-100 computer. Both 
products have proven to be sophisticated and reliable. 
Being able to count on this kind of stability has been a big 
plus. We may look into using the C or Pascal languages 
later on, but the microcomputer versions of these are still 
relatively new. 

The simplest choice of system software for low-cost 
computers like the Apple, Atari, and Radio Shack's 
TRS-80 is to use whatever is supplied by the manufac- 
turer. This can cause problems, however, and since it is 
now possible to add the CP/M-Microsoft BASIC com- 
bination to both the Apple and TRS-80, we may take this 
route later on. For the time being, we are trying to work 
with the system software supplied with each of these 
machines, supplementing it where necessary with bus in- 
terface programs written in machine language. 



Surrogate Applications 

By now it should be clear that putting together a 
system of this type is a complex job, especially for a small 
staff. Some of this complexity can be sorted out by 
recognizing that we (and, later on, others who wish to 
replicate the system) must wear three hats. The most im- 
portant of these will eventually be that of the educator 
who uses the system. The second will be that of the 
application-program designer. The third is the one we are 
wearing most of the time at present, namely that of a 
multisystem designer. The job of a multisystem designer 
has to come first since the others build on its products. 
The problem is that any decisions at the system level can't 
be made without experience at the application level. 

At this time, our strategy for dealing with this dilemma 
is to give consideration to a variety of educational ap- 
plications, but to hold off on implementing them fully. A 
considerable effort in software engineering will be needed 
to implement the more advanced applications we have in 



112 January 1981 © BYTE Publications Inc 



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Education Forum 



mind, and for these we feel that it is wisest to confine 
ourselves to the highest level of the application design 
process at present. The catch to this strategy is that it 
doesn't get into the nitty-gritty detail that can have im- 
portant repercussions on network -level design decisions. 
To handle this obstacle, we are also working with the 
complete design and testing of what we call surrogate ap- 
plications. These are highly simplified but fairly accurate 
mappings of what we believe will be the essential ingre- 
dients of real applications. 

The first surrogate application we have worked with is 
a game called MATSRCH. It was designed by Ivan 
Zatkovich as an undergraduate. He has since graduated 
and moved on to bigger and better things as a computer 
scientist. His application was designed to work with a 
minimal system in which an S-100 computer provides the 
network -bus function, while also handling several node 
tasks. 

The arrangement of components used in MATSRCH is 
shown in figure 2 and photos 2a and 2b. The S-100 com- 
puter consists of an IMSAI mainframe equipped with an 
Ithaca Intersystems Z80 processor board and memory 
boards, and a Morrow disk controller and I/O boards. 
The computer runs Microsoft 5.1 BASIC under CP/M. 
The nodes controlled by persons Pi, P2, P3, and so on, 
are equipped with low-cost machines such as the Apple 
II, the Atari 800, and the TRS-80. The processes in each 
of these machines are written in the BASIC supplied with 
the machine (usually a variant of Microsoft BASIC). 

The idea of MATSRCH is to allow several players, 
each with his own computer, to move a spaceship 
through a world defined by a matrix-like coordinate 
system. Players issue commands that move their ships, 
ask for scans of the area in which they are located, and 
rendezvous with other ships. The program running in the 
S-100 computer performs three tasks: it manages the 
communication of data between nodes (ie: it emulates the 
network bus function), it keeps track of where everybody 
is in the matrix world of the game (supplying this infor- 
mation to the WAG display), and it displays bus-status 
information on the system console. This last function is 
not essential to the game, but it is a revealing way to keep 
tabs on where the bottlenecks in communications occur. 

The present version of this simplified net monitor 
shows whether the S-100 program is doing network poll- 
ing (and buffer management), interpreting data received 
from the nodes, or handling the WAG display. 

The programs in the spaceship nodes are quite simple 
at present. They allow the players to issue commands 
that control the motion of their ships, and ask for infor- 
mation about the presence of other ships. The game limits 
the range that a player may ask to scan. In effect, in- 
dividual nodes are able to look into small windows on the 
global space known to the WAG. Each node application 
program is also able to call upon a suitable driver pro- 
gram that can transmit or receive data from the bus. The 
programs in the nodes are actually parallel processes that 
cooperate in the MATSRCH game. The important point 
to note is that these processes can be expanded to take ad- 
vantage of all the power of the microcomputer in which 
they reside. This is an important point; the local nodes 



114 January 1981 © BYTE Publications Inc 



Circle 67 on inquiry card. 



Circle 68 on Inquiry card. 



"When you sell to small 
business, learn to speak 
their language. COBOL- 80." 

Ron Mayberry 
May berry Systems, Inc., Belleville, Illinois 



"It's amazing what a 
few key phrases will do 
for your sales record 
to small businesses. 
Words like "faster," 
"cheaper," and 
Microsoft's "COBOL-80" 

I should know. I'm in 
the business of selling 
complete computer sys- 
tems to one of the most 
demanding enterprises 
around: pharmacies. 
That means my pro- 
grams have to solve 
the complex problems 
facing pharmacies today 
—the deluge of paper- 
work, regulations, and 
the need for immediate 
access to patient 
information. 

I've sold a lot of mini- 
computer systems with 
programs written in 
DIBOL. Then I discover- 
ed microcomputers, 
and Microsoft's 
COBOL-80. Together, 
they're faster and less 
expensive than my old 
system, yet do all the 
same things. And more. 

Like what? Like 
more flexibility and ver- 
satility. I use practically 
the whole range of 
COBOL-80 features, to 
speed inventory, billing, 
labeling, pricing, 
accounts receivable, 
patient profiles and 




doctor lists. And I'll be 
using a lot of the same 
features to write a pro- 
gram for travel 
agents too. 

Believe me, we 
checked them all, and 
only COBOL-80 had all 
the necessary LEVEL II 
features, plus the new 
CHAIN feature, pro- 
gram segmentation 
and formatted screen 
ACCEPT/DISPLAY. 

The CHAIN feature 
impressed even a 
veteran programmer 
like me. With my menu- 
driven systems, I have 
total control over which 
program will execute 



next. And it was great to 
find that COBOL-80's 
ACCEPT/DISPLAY 
statements give for- 
matted screens that 
look the same as my old 
DIBOL screens. Yet 
with fewer lines of code. 

With 300 different 
program modules, you 
can be sure I appre- 
ciate segmentation too. 
In one case, I collapsed 
seven DIBOL programs 
into one segmented 
COBOL-80 program. 
Now I can organize my 
system according to 
program function rather 
than memory size. 



My compile times? 
Incredible. Over 1,500 
lines compile and link in 
just five minutes. 

I know what you're 
thinking. 'Sounds great, 
but I wouldn't want to be 
in Mayberry 's shoes 
when he translated all 
those DIBOL programs 
to COBOL-80.' Well, 
surprise. Since most 
Dl BOL features trans- 
late into COBOL one- 
for-one, we converted 
the source code six 
times faster than 
originally scheduled. 

So simply put, that's 
how Mayberry Systems 
Inc. learned for itself 
that COBOL-80 is one 
language that makes 
a lot of sense to 
small businesses. 

In my opinion, 
COBOL-80 is first- 
class. And I thought 
you should know about 
it too." 

COBOL-80 now sup- 
ports Level II ANSI 
SORT/MERGE state- 
ments to interface with 
Microsoft's new sort 
facility, M/SORT. 

COBOL-80 with 
documentation, $750. 

Documentation purchased 
separately, $20. 

M/SORT, $125. 



10800 NE Eighth, Suite 819 

Bellevue, WA 98004 
206-455-8080 Telex 328945 

We set the standard. 



Education Forum 



S-100 MICROCOMPUTER RUNNING MICROSOFT BASIC UNDER CP/M 




MATSRCH LOCAL PROCESSORS 



Figure 2: The hardware and software arrangement for MATSRCH. This application uses an S-100 computer (indicated at the top of 
the diagram) for a variety of functions: the segment labeled "BUS" is involved in emulating the unrooted-tree network shown in 
figure 1. Each microprocessor node has a principal function (the task assigned to that node, indicated by a square) and a driver pro- 
gram that handles communications (indicated by a diamond). 



are not just terminals connected to a central processor. 

As was noted earlier, all communications between 
nodes are via RS-232C serial lines. Thus, even though our 
work is primarily concerned with a local network, there 
is still the capability of connecting several schools 
together via telephone lines and modems. The potential 



6809 3-100 "k 

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of interscholastic simulation gaming between several 
local high schools and colleges is intriguing, especially in 
terms of the higher levels of supportive social en- 
vironments that could result. ■ 



Acknowledgments; Further Information 

The Solo/NET/works project derives many of its 
ideas from its two predecessors, Project Solo and the 
Soloworks Laboratory. All three projects were funded 
in part by the Education Directorate of the National 
Science Foundation. Examples of early curriculum 
units from Project Solo were reprinted in Creative 
Computing in 1979 and 1980. Articles describing some 
of the activities of Soloworks appeared in BYTE in 
December 1976, August 1977, March 1978, and May 
1978. A description of the educational ideas that 
underlie the Solo philosophy was given in the article 
"Books As an Antidote to the CAI Blues" which ap- 
peared in the Education Forum of BYTE in June 1980, 
page 74. 

Documentation of the Solo/NET/works project will 
initially be in the form of working papers. These are 
for internal use only, but revised versions will later be 
submitted for publication in the Education Forum of 
BYTE. If you'd like to be placed on a mailing list for a 
notice of what has been published and where it ap- 
peared, send your name and address to Margot 
Critchfield, Department of Computer Science, Univer- 
sity of Pittsburgh, Pittsburgh PA 15260. However, 
please understand that it will be some time before a 
complete list is available. 

The material in this preliminary report is based in 
part on working papers by faculty associate Dr Sig 
Treu, and project staff members Margot Critchfield, 
Bob Hoffman, and Blaise Liffick. The material on the 
MATSRCH application was derived from a paper in 
preparation by Ivan Zatkovich. 



116 January 1981 © BYTE Publications Inc 



Circle 69 on Inquiry card. 



A PASCAL/M Demo Disk from Sordm. 



You've heard all about the power of PASCAL. You know it's a 
simple, high level, block structured language that is replacing 
BASIC as the universal programming tool. But how can you 
learn if it's really what you want without spending a lot of 
money? Sorcim's Incredible $10 Free Offer is the answer. 

For only $10 you receive a CP/M® compatible 8" 
floppy disk that demonstrates the entire PASCAL/M 
language. Through a sample pro- 
gram that displays the unique 
features of PASCAL/M and a 
limited compiler that allows 
you to create programs of 
your own, you'll discover 
the incredible world of 
PASCAL/M first-hand. 

You can run the disk on any 
standard CP/M-based system using an 8080, 
8085 or Z80'- CPU device with 56K memory. 
So where's the FREE come in? 

After the demo disk gets you hooked on 
PASCAL/M, just order the full PASCAL/M 
package, including the compiler, object library 
and pseudo code (P-Code) interpreter, and 
we'll give you full credit for the demo disk! 




That's $10 off of our regular low price of $175. And that makes it 
about as close to free as you can get. 

If you need full documentation, just turn your Incredible 
$10 Free Offer into an Incredible $20 Free Offer. Order the 
complete 90-page User's Reference Manual, which fully details 
our entire PASCAL/M package, for an additional $10. 
And you'll get full credit for the $20 offer, too. 

Sordm Is the solid software source. 
Sorcim is fully committed to the advance- 
ment of technology through software develop- 
ment. Our next PASCAL enhancement, the 
PASCAL/M symbolic debugger which dra- 
matically reduces program development time, 
is proof of this commitment. We also offer a 
comprehensive line of state-of-the-art software 
products for Z80, 8080, 8048, 6502, 680x, 
Z8000, M68000 and 8086/88 microprocessor- 
based systems. And Sorcim can develop operat- 
ing systems, compilers and assemblers for your 
specialized applications. 

Take advantage of our incredible offer by 
filling out the coupon and sending it to us 
today. You'll get hard evidence of solid software 
for microcomputer applications. 



THE INCREDIBLE 
$10 FREE OFFER" 



OK, I can't pass up your Incredible $10 Free Offer. 
Please send me the Items checked below: 

□ PASCAL/M Demo Disk $ 10.00 

□ PASCAL/M User's Reference Manual $ 10.00 

□ Demo Disk and Reference Manual $ 20.00 

I understand that I'll receive full credit for my Incredible $10 (or 
$20) Free Offer if I order the full PASCAL/M package by July 
31, 1981. 

□ I can't stand it; I've got to have the full PASCAL/M package, 
including Compiler, Object Library, P-Code Interpreter, Ref- 
erence Manual and Demo Disk. 

□ Z80* □ 8080/85* □ Z80/951 1* 
*S/xKi)5>.-nCP/MornCDOS $175.00 

□ 8088/86 (Requires CP/M 86) $250.00 

□ Master Card □ VISA □ Ship UPS COD. 

□ Check or money order enclosed 

Card Number Exp. Date 

Master Card Interbank Number 



Signature 

(for credit card purchase) 
Total amount enclosed 



PASCAL/M is a trademark of Sorcim 

CP/M is a registered trademark 

of Digital Research 

Z80 is a trademark 

of Zilog Corporation 



(California residents add 6.5% sales tax; for overseas shipment, add $10.00; 
for shipment to Canada or Mexico, add $5.00.) 

SHIP TO: 

ADDRESS: 

CITY:_ 

STATE: 



(No P.O. boxes, please) 



.ZIP_ 



K 

SORCIM 

1333 Lawrence Expressway 

Suite 418 

Santa Clara, CA 95051 

(408)248-5543 




Circle 70 on Inquiry card. 



BYTE January 1981 117 



System Review 



The HP-41C: 
A Literate Calculator? 



Brian P Hayes 

Scientific American 

415 Madison Ave 

New York NY 10017 



Calculator vs Computer 

The computer and the programmable calculator seem 
to be following paths of convergent evolution. As the one 
is made smaller while the other gains in capability, the 
line of demarcation between them becomes more and 
more arbitrary. For now at least, the programmable 
calculator remains a distinct and lesser species, but it 
shares many of the attributes of the computer. Moreover, 
the shared attributes are chiefly the ones that make the 
computer an interesting machine. Both devices offer an 
intimate acquaintance with the powers and pleasures of 
algorithms. Both exhibit an enigmatic unpredictability: 
the response of the machine to any given stimulus is 
wholly deterministic, yet the behavior of a large program 




Photo 1: Components of the Hewlett-Packard HP-41C 
calculator system. Shown here are the calculator itself and three 
peripheral devices: a magnetic-card reader, a wand for reading 
printed bar codes, and a thermal dot-matrix printer. The 
peripheral units plug into four ports at the top of the calculator, 
which can also receive modules containing additional memory 
or preceded applications programs. The HP-41C alone costs 
about $300; a system including all three peripheral devices and 
two memory or applications modules is about $1000. (Photo by 
Ed Crabtree.) 



can be full of surprises, often to the frustration of the pro- 
grammer. 

The HP-41C, which was introduced by the Hewlett- 
Packard Company about a year ago, is among the pro- 
grammable calculators that lie closest to the computer 
borderline. It comes close enough for the jargon of com- 
puters to be useful in describing it. At the Corvallis Divi- 
sion of Hewlett-Packard, where the HP-41C is made, 
they refer to the calculator itself as the "mainframe" and 
to its accessory devices as the "peripherals." The 
calculator comes equipped with four input/output (I/O) 
ports, through which the various elements of the system 
are interconnected. Because the peripherals do some data 
processing internally, the system might even be said to 
have "distributed intelligence." 

When compared with a computer, most programmable 
calculators have a rich instruction set, but they are defi- 
cient in memory capacity and in facilities for communica- 
tion with the user. A calculator comes with such 
amenities as trigonometric, logarithmic, and statistical 
functions built in; with a computer, even floating-point 
arithmetic must usually be constructed out of software. 
On the other hand, no calculator has the memory needed 
to store large tables or other data structures. And it is the 
communication problem that most seriously limits the 
utility of the calculator. A display that can represent only 
the 10 digits, a decimal point, and a minus sign does not 
have much range of expression. Even for problems that 
have entirely numerical results, such a display is not 
always adequate, since without labeling of any kind it is 
easy to become confused about what a number means. 

The HP-41C 

In the HP-41C, the instruction set is at least the equal 
of that in any other calculator and the potential memory 
space is large (although it can never be large enough). 
The most conspicuous distinguishing features, however, 
have to do with communications and "human factors " 
(or, in other words, those things that aid in writing pro- 
grams and in interpreting their results). 

All three of the peripheral units now available serve to 
get information into or out of the HP-41C; they are a 
printer, a magnetic-card reader, and a wand for reading 
bar codes. But perhaps the most significant innovation of 
all is in the calculator itself: a liquid-crystal display that 
can represent not only numerals but also the complete 
uppercase alphabet and a few lowercase letters and other 



118 January 1981 © BYTE Publications Inc 



The first personal computer 
fM- under $20tt 



The Sinclair ZX80. 
A complete computer- 
only $199. 95 plus $5. 00 shipping. 

Now, for just $199.95, you can get a 
complete, powerful, full-function computer, 
matching or surpassing other personal 
computers costing several times more. 

It's the Sinclair ZX80. The computer that 
"Personal Computer World" gave 5 stars 
for 'excellent value.' 

The ZX80 cuts away computer jargon 
and mystique. It takes you straight into 
BASIC, the most common, easy-to-use 
computer language. 

Yqu simply take it out of the box, con- 
nect it to your TV, and turn it on. And if 
you want, you can use an ordinary cassette 
recorder to store programs. With the man- 
ual in your hand, you'll be running programs 
in an hour. Within a week, you'll be writing 
complex programs with confidence. 

All for under $200. 

Sophisticated design makes the 
ZX80 easy to learn, easy to use. 

We've packed the conventional computer 
onto fewer, more powerful LSI chips— 
including the Z80A microprocessor, the 
faster version of the famous Z80. This 
makes the ZX80 the world's first truly port- 
able computer (6V2" x 8V2" x 1V2" and a mere 
12 oz.). The ZX80 also features a touch 
sensitive, wipe-clean keyboard and a 
32-character by 24-line display. 

Yet, with all this power, the ZX80 is easy 
to use, even for beginners. 



^e-nBASiCpm 




Your course in computing. 

The ZX80 comes complete with its own 
128-page guide to computing. The manual 
is perfect for both novice and expert. For 
every chapter of theory, there's a chapter 
of practice. So you learn by doing— not just 
by reading. It makes learning easy, exciting 
and enjoyable. 

You'll also receive a catalog packed with 
items that can make your ZX80 even more 
useful. Including 27 program cassettes, 
from games and home budgeting for just 
$6. 95, to Sinclair's unique Computer Learning 
Lab. And books, hardware options and 
other accessories. 

ZX80's advanced design features. 

Sinclair's 4K integer BASIC has perfor- 
mance features you'd expect only on much 
larger and more expensive computers. 
■ Unique 'one touch' entry. Key words 

(RUN, PRINT, LIST, etc.) have their 

own single-key entry to reduce typing 

and save memory space. 




■ Automatic 
error detection. 
A cursor identifies errors 
immediately to prevent entering 
programs with faults. 

■ Powerful text editing facilities. 

■ Also programmable in machine code. 

■ Excellent string handling capability— up 
to 26 string variables of any length. 

■ Graphics, with 22 standard symbols. 

■ Built-in random number generator for 
games and simulations. 

Sinclair's BASIC places no arbitrary re- 
strictions on you— with many other flexible 
features, such as variable names of any 
length. 

And the computer that can do so much 
for you now will do even more in the fu- 
ture. Options will include expansion of IK 
user memory to 16K, a plug-in 8K floating- 
point BASIC chip, applications software, 
and other peripherals. 

Order your ZX80 now! 

The ZX80 is available only by mail from 
Sinclair, a leading manufacturer of con- 
sumer electronics worldwide. 

To order by mail, use the coupon below. 
But for fastest delivery, order by phone 
and charge to your Master Charge or VISA. 
The ZX80 is backed by a 30-day money- 
back guarantee, a 90-day limited warranty 
with a national service-by-mail facility, and 
extended service contracts are available for 
a minimal charge. 



Price includes TV and cassette connectors, 
AC adaptor, and 128-page manual. 

All you need to use your ZX80 is a standard TV 
(color or black and white). The ZX80 comes complete 
with connectors that easily hook up to the antenna 
terminals of your TV. Also included is a connector for 
a portable cassette recorder, if you choose to store 
programs. (You use an ordinary blank cassette.) 

Hi 




The ZX80 is a family learning aid. Children 10 and 
above will quickly understand the principles of 
computing— and have fun learning. 

Master Charge or VISA orders call: 

(203) 265-9171. We'll refund the cost of your call. 
Information: General and technical— (617) 
367-1988, 367-1909, 367-1898, 367-2555. 
Phones open Monday-Friday from 8 AM to 
8 PM EST. 



inczlaii— 



Sinclair Research Ltd., 475 Main St., 
P.O. Box 3027, Wallingford, CT 06492. 



To: Sinclair Research Ltd., 475 Main St., P.O. Box 3027, Wallingford, CT 06492. 

Please send me ZX80 personal computer(s) at $199. 95* each (US dollars), plus $5 



shipping. (Your ZX80 may be tax deductible.) 

I enclose a check/money order payable to Sinclair Research Ltd. 

Name 



for$_ 



Address- 
City 



.State_ 



.Zip. 



Occupation: 

Intended use of ZX80: 



- Age: . 



Have you ever used a computer? D Yes □ No. 

Do you own another personal computer? □ Yes □ No. 



"For Conn, deliveries, add sales tax. 



symbols. The letterforms are crude but perfectly legible; 
what they bring to the calculator is literacy, and it makes 
all the difference in man-machine relations. 

The architecture of the HP-41C is not fundamentally 
different from that of its predecessors in the Hewlett- 
Packard line. There is a four-level stack of registers where 
pending operands are generally held; other registers are 
identified by a 2- or 3-digit address. The internal memory 
consists of 63 registers, but this number can be increased 
by plugging memory modules into the ports. Each 
module adds 64 registers, so that a full complement of 
four modules yields a total capacity of 319 registers; with 
all the ports occupied, however, no peripheral devices 
can be connected. 

The memory available can be divided in any way 
desired between data storage and program storage. When 
allocated to data memory, a register holds a single 
floating-point number (10-digit mantissa and 2-digit ex- 
ponent). Program capacity is more difficult to measure 
because instructions have varying space requirements. 
Without extra memory and with a reasonable allowance 
for data storage, the maximum for an unassisted HP-41C 
usually falls between 150 and 200 program lines. By add- 
ing three modules and keeping the same data space, the 
program capacity is expanded to about 1200 lines. 

An additional wider register is dedicated to alphabetic 
operations. Up to 24 characters can be accumulated in the 
alpha register, although only 12 at a time fit in the liquid- 
crystal display; the extra characters scroll in to the left, 
marquee-style. The alphabetic capability is not a mere 
frill. The extent to which it is called upon in the everyday 



REMOTE I/O 




Control AND monitor remote devices 
Real time clock/calendar included 

• An AC carrier communications I/O interface for the APPLE II* 
computer. Output communications operate up to 256 BSR System 
X-10* control modules. Input communications come from the X-10 
command console, and temperature and security input modules, 
soon to be available from Intelligent Control Systems, Inc. 

• Software routines are provided to handle the AC I/O, to set, 
read, and display the real time clock, and a background schedule 
control program. 4 selectable interrupt rates allow machine 
language programs to run simultaneously with other programs. 

• Real time clock provides sec , min , hour , date , day of week , mo, 
and year. Rechargable battery runs clock when APPLE is off. 

• Trademark s-APPLE II : Apple Computer Inc. , System X-10 :BSR Ltd. 
SEE YOUR APPLE DEALER FOR A DEMONSTRATION. .. $185 sugg. retail 

Intelligent Control Systems, Inc. 

POBOX 14571«MPLS,MN 55414* (612) 699-4342 



operation of the calculator can be illustrated by consider- 
ing one of the curious challenges of calculator design. 

Mnemonic Functions 

The problem is that most scientific calculators have 
more instructions than they have keys; in the case of the 
HP-41C, there are more than 130 instructions and only 
thirty-five keys. A shift function doubles the number of 
distinguishable key sequences, but that still leaves almost 
half the instruction set without a home on the keyboard. 
Rather than further increase the number of keys or the 
number of shifted modes, Hewlett-Packard has adopted a 
solution familiar in larger systems: all instructions, 
whether or not they appear on the keyboard, can be ex- 
ecuted by spelling out their mnemonic in the display. 
Programs resident in memory and instructions associated 
with peripheral devices can be executed in the same way. 

Execution of a mnemonic label has the significant ad- 
vantage of eliminating all dependence of the instruction 
set on the layout of the keyboard. It also has certain 
potential drawbacks that the designers of the HP-41C 
have gone to some lengths to remedy, largely by ex- 
ploiting the alphabetic display. For example, if the spell- 
ing of a mnemonic is forgotten, a complete listing of the 
instruction set can be called up by the CATALOG func- 
tion. 

Another objection is that repeatedly spelling out a 
function can be tiresome on a keyboard smaller than the 
human hand. This burden has been relieved by the 
radical strategy of allowing all the keys to be redefined by 
the user. Any instruction (with the exception of a few 
program-editing pseudoinstructions) and any program 
can be assigned to any key. 

The fluid indeterminacy of the keyboard leads to a fur- 
ther possible complaint: the user may lose track of what 
function has been assigned to a particular key. Two 
devices come to the aid of the forgetful. A keyboard 
overlay slides into place to relabel the keys according to 
the chosen assignments; if several programs require dif- 
ferent key assignments, a separate overlay can be made 
up for each one. The second aid is more elegant: the cur- 
rent function of any key can be verified merely by press- 
ing the key and holding it down a moment. The 
mnemonic of the function appears in the display. If the 
key is released, the function is executed; otherwise, the 
word "null" appears and the command is canceled. 

I A third aid to the use of the HP-41C keyboard is the 
selection of the user/standard mode. The key redefini- 
tions are valid only when the calculator is in the user 
mode. To use a key that has been redefined for its 
original function, the user has only to press the USER key 
to toggle the calculator back to its standard mode. In the 
standard mode, the HP-41C behaves as it would before 
any keys were assigned, thus giving the user the best of 
both worlds. . . . GW] 

Further Features for the Programmer 

The versatility of the liquid-crystal display is exploited 
in several other ways to make the HP-41C friendly and 
fool-resistant. A row of indicators below the main 
display provides various indications of mode and status. 
Error messages can be reasonably explicit: an attempt to 
divide by elicits "data error," and a number greater 
than 10" is flagged as "out of range." When a conditional 



120 January 1981 © BYTE Publications Inc 



Circle 71 on inquiry card. 



Circle 72 on inquiry card. 



NEW DISK SYSTEM 
POLISHES APPLE 






s-n 



■ 



■ 



»hSM 



I 



I 



... J • 



Micro-Sci's new disk drive family 
really makes your Apple shine. 

Both the A-40 and A-70 offer 
extra performance plus the ability 
to read existing diskettes written 
on Apple Disk II systems. 

And a jumper selectable boot 
prom for 13 and 16 sector interger 
Basic or 8 sector Pascal comes 
standard. 

The Model A-40 actually costs 
a lot less than Apple Disk II drives. 
Yet it provides 40 tracks instead of 



35, along with up to 20K increase 
in capacity. Maybe an extra 20K isn't 
anything to write home about, but 
the speed sure is — 5 ms track to 
track vs. Apple's 15 ms. 

The Model A-70, on the other 
hand, features twice the tracks and 
capacity of the Apple Disk II, but 
it costs only a few dollars more. 

The secret of outstanding per- 
formance and reliability is a state- 
of-the-art design incorporating a 
band positioner, instead of a plastic 



fj-sa 



cam, plus an improved media 
centering system. 

SPECIAL DISCOUNT. 

One A-40 plus controller is priced 
at only $495 and the second drive 
is just $395. You can save 
up to $200 per system over Apple II 
drive prices. 

And you can save even more if 
you act now. Contact us today for 
a special $50 introductory discount 
on your Micro-Sci A-40 or A-70 
system order. 



MICRO-SCI 
1405 E. CHAPMAN AVENUE • SUITE E • ORANGE, CALIFORNIA 92666 

MICRO-SCI IS A DIVISION OF STANDUN CONTROLS, INC. 
Apple and Apple II are registered trademarks of APPLE COMPUTERS INC., SAN JOSE, CALIFORNIA 



714/997-9260 



test, such as "X = 07", is executed from the keyboard, 
the display answers the question "yes" or "no." 

Alphabetic text can also have a valuable role within a 
program. How it is employed is largely up to the pro- 
grammer, but two obvious uses are prompting for inputs 
and labeling outputs. 

Even with the best of keyboard technologies, entering a 
long program is inevitably tedious. A feature of the HP- 
41C that helps in avoiding needless repetition of effort is 
a continuous memory, which maintains all data and pro- 
grams even when the calculator is turned off. Key 
assignments, the settings of flags, and other status infor- 
mation (such as the angular mode) are also preserved. A 
program that is run frequently can be kept in the 
calculator. Memory resources are finite, however, and on 
occasion a program must be cleared to make room for 
another and later reloaded. It is for such purposes that 
the magnetic-card reader and the bar-code reader are in- 
tended. 

Using Cards 

The magnetic-card reader, which occupies one port, is 
a small unit that clips onto the top of the calculator and 
can be left in place. The cards are the standard 1 by 
7 cm magnetic strips (slightly smaller than a stick of 
chewing gum) that are also employed by the HP-67 and 
HP-97 and by some Texas Instruments calculators. They 
are inserted in a slot at the side of the reader and pulled 
through by a motor for retrieval on the other side. Each 
card has two tracks and each track holds the contents of 
16 registers, which can be either data or programs. A 





olVo 

cut vrco 

kV* *<* 






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122 January 1981 © BYTE Publications Inc 



Circle 73 on inquiry card. 



long program requires several cards, and a routine that 
saves the state of the entire machine sometimes calls for a 
whole deck of them. 

Cues provided by the calculator make operations with 
the cards almost mindless. When writing a program onto 
cards, a message in the display indicates how many 
tracks will be needed; when reading a program, the same 
message gives the lowest-numbered track that has yet to 
be read. The cards can be inserted in any sequence, and 
the information is sorted out internally. A defective card 
or an unsuccessful pass through the slot generates an ap- 
propriate error message. 

Cards can be both written and read at the command of 
a running program. For example, a data card might be re- 
quested during an initialization routine, and new values 
might be written onto the card at the end of a calculation. 
Or one of several possible subroutines might be appended 
to a running program once the program had determined 
which subroutine was needed. Unfortunately, all these 
procedures still require human intervention for the actual 
insertion of the card. Thus, the user must attend the 
machine and feed it by spoonfuls on demand. 

An amusing feature of the card reader is its ability to 
create "private" program cards. When such a card is read 
back into the calculator, the program appears in the 
catalog and becomes available for execution, but it can- 
not be examined, modified, or copied onto another card. 
Any attempt to do so is blocked by the imperious 
message "private." The security measures seem to be ef- 
fective (although I have not worked seriously at 
penetrating them); how often they will be needed is 
another question. In the realm of very-small-scale 
systems, the major worry is theft of hardware, not soft- 
ware. 

Software Compatibility 

The introduction of a new model computer often raises 
questions of software compatibility. In this case, 
Hewlett-Packard has made the new machine compatible 
with the old software by including a translator routine in 
the card reader. Magnetic cards written on the HP-67 or 
HP-97 can be entered into the HP-41C and, with no in- 
tervention by the user, will be converted into HP-41C 
programs. Thus, the machine has access to the large body 
of software written for the earlier calculators, including 
more than 3000 programs in a users' library administered 
by Hewlett-Packard. 

An incidental benefit is the addition of more than a 
dozen instructions peculiar to the HP-67 and HP-97 that 
become available on the HP-41C whenever the card 
reader is plugged in, even though most of those instruc- 
tions have nothing directly to do with card operations. 
For example, there is a block-memory swap that comes in 
handy occasionally. 

Bar-Code Wand 

One drawback of magnetic-card recording is the cost 
of the medium: roughly fifty cents a card, plus the con- 
siderable expense of the card reader itself. There is also 
the delicacy of the iron-oxide surface, which necessitates 
careful storage and the maintenance of duplicate copies 
for backup. A second input device for the HP-41C, the 
bar-code reader, relies on the most inexpensive of all 
known storage media, ink on paper. The reader is a 

Circle 74 on inquiry card. > 



INTERFACE PRODUCTS FOR THE 80's 



Multiport Serial Card 

• Two or Four RS-232 serial ports with full handshaking. 

• Independent baud rate generator for each port, with 16 
software selectable rates from 50 to 19200 baud. 

• Handshake lines include hardware start/stop control for 
each port to interface with serial printers without additional 
software. 

• Each port can be configured as a "data set", for direct 
connection to a terminal, or a "data terminal", for direct 
connection to a modem. 

• 8-level vectored interrupt controller handles receive and 
transmit interrupt requests from each port. 

• Interrupt controller may be slaved to our CPU Support Card 
for fully vectored operation or it may be used in the "polled 
mode" while retaining the interrupt masking and prioritiza- 
tion features. 




' Both of these cards are IEEE 696 (S- 1 00) compatible. They 
have DIP switches for I/O port address and all options are 
set with switches or easy-to-use pin shunts. 

Price: 2-port, $250; 4-port, $350. Manual only, $3. Cables 
$15 each in 14, 18, or 28 inch lengths. 



CPU Support Card 

• RS-232 serial port with full handshaking. Software- 
controlled baud rate generator allows almost any conceiva- 
ble data rate. 

• Socket for 2716 or 2732 EPROM. The EPROM can drive 
PHANTOM to allow a memory board to overlap, and it can 
be disabled with an output command. 

• 8-bit parallel input and output ports, each latched and with 
full handshaking. 

• Vectored interrupt controller. Provides 15 levels of vectored 
interrupts, expandable to 64 through "slave" controllers on 
other cards (such as our Multiport Serial). Includes 
complete interrupts support for 8080, 8085, Z80, and 8086 
microprocessors. 

• Two general-purpose timer/counters, Each is 16 bits wide. 
One may be combined with the time-of-day clock to count 
days. 




* Time-of-day clock. Time of day is kept in 24-hour format to 
0.01 second. Power to run the clock may be provided from 
an external source, such as a battery, to keep the clock 
running when the computer is off. If time of day is not 
needed, the clock may be used as two general-purpose 16- 
bit timers. 

Price: Card, $370. Manual only, $4. Cables, one 28" cable 
provided. Additional cables, see above. 2716 EPROM 
(single supply), $15 each or $13 in 10s. 



From Seattle Computer, the System Design Experts 



While each of these cards is a great individual 
performer, together they form an unequalled interrupt 
system. Up to seven Serial cards may have their on- 
board interrupt controllers slaved to the master control- 
ler on the Support Card for a maximum of 64 different 
interrupt sources. Only SCP provides this kind of 



expandability required for the multi-user systems of the 
80's. 

To help you tap the power of this system, each CPU 
support card includes source code on diskette of a 
complete, fully interrupt-driven I/O system for MP/M. 
(MP/Mis a trademark of Digital Research Corporation.) 



These products may be purchased from your local computer store. 
Products are guaranteed one year — both parts and labor. Factory orders 
shipped prepaid In USand Canada. Foreign purchases must be prepaid In 
US funds. Also add $10 per board for overseas air shipment. 



A 



Seattle Computer Products, Inc. 

1114 Industry Drive, Seattle, WA. 98188 
(206) 575-1830 



hand-held wand similar to a general-purpose one in- 
troduced some months ago (the Hewlett-Packard 
HEDS-3000), but it has an interface and a plug specifical- 
ly adapted to the HP-41C. 

With programs encoded and printed by Hewlett- 
Packard, the wand works extremely well. A line of code 
can be scanned in either direction, although multiple lines 
must be read in sequence. The calculator display prompts 
for the lowest-numbered line not yet read. Even more 
helpful is audible confirmation. After each successful 
pass, the calculator emits a high-pitched beep; a failure 
results in a lower-pitched tone. The speed and orientation 
of the wand are not critical, and with practice the success 
rate becomes quite high. 

The wand can also do a few things besides the 
straightforward loading of programs. Individual instruc- 
tions can be executed from a "paper keyboard" (which is 
a table of bar codes, each of which is a single HP-41C in- 
struction); data can be entered directly into designated 
storage registers; subroutines can be appended and pro- 
grams merged. One wand function, instead of translating 
the scanned bar code into HP-41C operation codes, 
displays the actual binary value represented by the bars. 

Printed machine-readable code is an ideal medium for 
the mass distribution of programs, and Hewlett-Packard 
will reportedly make all its software for the HP-41C 
available in this form. Programs from the users' library 
will also be offered in bar code, presumably at a lower 
price than programs on magnetic cards. For frequent 
users of such prepared software, bar code seems to be the 
medium of choice. 



The situation is somewhat different, however, for 
those whose main interest is in writing their own pro- 
grams rather than in running other people's. The trouble 
is that bar code, for now, remains largely a one-way 
channel of communication. 

It is possible to assemble by hand a bar-code represen- 
tation of a program. The basic materials are adhesive 
labels, each bearing the code for a single instruction or a 
single numeric or alphabetic character. [The "paper 
keyboard" can also be photocopied, with a program be- 
ing created by cutting and pasting photocopied bar-code 
keystrokes. . . . GW] A long program, however, would 
require several hundred labels; moreover, they must be 
scanned as a series of many short strokes. The ability to 
reproduce the program by photocopying might 
sometimes compensate for this inconvenience, although 
the wand owner's manual warns that such copies may not 
always give acceptable results. (Three copying machines I 
tried all produced readable images, although the error 
rate was somewhat higher than with originals.) 

For those who have access to a computer system that 
includes a daisy-wheel printer or a plotter, Hewlett- 
Packard will supply programs in BASIC or FORTRAN 
that will generate bar code in the HP-41C format. A far 
more appealing method would be to produce the bar code 
on the printer in the HP-41C system; if that could be 
done, the wand might entirely displace the magnetic-card 
reader. The HP-41C printer can readily be made to 
generate patterns that superficially resemble bar codes. In 
several weeks of experimenting, however, I have been 
unable to persuade the wand to recognize those patterns 



9f Micros aren't just for games anymore- 
AARDVARK gets down to brass TAX. 99 



AARDVARK SOFTWARE takes home com- 
puter use one practical step further with "Per- 
sonal Tax," a federal income tax program 
designed specifically for home use. 

"Personal Tax" was developed by CPA's 
and computer professionals. It will calculate 
Federal Forms 1040 and 4726, as well as sched- 
ules A, B,G and TC. The program features mul- 
tiple entries for a variety of inputs (e.g. wages, 
dividends and charitable contributions). An in- 
dexed instruction manual and easy-to-follow 
input forms are included. 

"Personal Tax" computes quickly and 
accurately, then displays or prints the totals 
automatically (using a standard printer inter- 



face). You simply copy the totals onto your IRS 
forms. 

This spring, use your microcomputer to 
simplify your taxes and file with confidence ! 
You won't have to spend half of your refund 
either. The "Personal Tax" program is very 
affordable at only $75. 

"Personal Tax" will run on: Apple II ,TRS 80 
Models I and II, and OSI. Additionally, under 
CP/M, the program will run on Vector Graphics , 
North Star and Cromemco. 

Minimum machine requirements: 
48K and one disk drive. 
Send check or money order, or, write us for 
more information. 



AARDVARK SOFTWARE INC 



The Microcomputer People for Professionals 

783NORTH WATER STRE El MILWAUKEE WISCONSIN 53202 414/289-9988 






124 January 1981 © BYTE Publications Inc 



Circle 75 on inquiry card. 



THE PERFECT MARRIAGE 



CHRISLIN 256KB MEMORY 




milium Hill 



»tuBfc 



B p B *ftl«»*\ 

BHB™. B B B B ™ \^k, i 

iiiiiiBit\v 



[iliiiiuWm uu\n\\\\\\\\\\\ 



DEC® LSI® 11/23 



NOW AVAILABLE! 256KB memory on a dual height board only $1925. CHRISLIN INDUSTRIES 
now offers state-of-the-art 64K RAM Memory system designs. Like our recently introduced 
512KB MULTIBUS® compatible single card memory our 256KB LSI 11/23 memory is an 
industry first. 

Free up critical and expensive backplane space. Saves you 3 dual slots. 

Addressable in 4K increments up to 4 Megabytes. 

On board parity generator checker totally DEC hardware and software compatible. 

Single 5 volt power requirement. 

Battery back-up capability. 256KB unit draws less than 300 ma at 5 volts in battery back-up 
mode. 

Tested and burned in. Full year warranty. 



DON'T ASK WHY WE CHARGE SO LITTLE, ASK WHY THEY CHARGE SO MUCH. 



c 



Chrislin Industries, Inc. 

Computer Products Division 
31352 Via Colinas • Westlake Village, CA 91362 • 213-991-2254 



Circle 76 on Inquiry card. 



Multibus is a trademark of the Intel Corp LSI II is a trademaik ol Digital Equipment Corp 



BYTE January 19SI 125 



SORCERER" 
SOFTWARE! 



Unless otherwise noted, all programs are on cassette and 
require only 8K of memory. 

FORTH 

new! Now Sorcerer owners can enjoy the convenience and speed of the fascinating FORTH 
programming language. Based on FIGFORTH and written by James Albanese, this version 
was designed especially for the Sorcerer and includes the capability to read and write data 
(screens) to cassette tape and a complete on-screen editor. Requires at least 16K of RAM. 

$49.95 

new! GRAPHICS ANIMATION by Lee Anders. This package provides the BASIC program- 
mer with a powerful set of commands for graphics and animation. The program is written in 
machine language but is loaded together with your BASIC program and graphics definitions 
with a CLOAD command. Any image from a character to a large graphic shape may be 
plotted, moved, or erased with simple BASIC commands. Encounters of plotted character 
sets with background characters are detected and background images are preserved. Con- 
tains a medium resolution plotting routine. A keyboard routine detects key presses without 
carnage returns. Includes a separate program for constructing images. $29.95 

new! STARBASE HYPERION™ by Don Ursem. At last, a true strategic space game for the 
Sorcerer! Defend a front-line Star Fortress against invasion forces of an alien empire. You 
create, deploy, and command entire ship squadrons as well as ground defenses in this 
complex tactical simulation of war in the far future. Written in BASIC and Z-80 code. Full 
graphics and realtime combat status display. Includes full instructions and STARCOM battle 
manual. Requires at least 16K of RAM. $17.95 

new! HEAD-ON COLLISION'" by Lee Anders. You are driving clockwise and a computer- 
controlled car is driving counter clockwise. The computer's car is trying to hit you head on, 
but you can avoid a collision by changing lanes and adjusting your speed. At the same time 
you try to drive over dots and diamonds to score points. Three levels of play, machine 
language programming, and excellent graphics make this game challenging and exciting for 
all. At least 16K of RAM is required. $14.95 

new! LUNAR MISSION by Lee Anders. Land your spacecraft softly on the moon by 
controlling your craft's three propulsion engines. Avoid lunar craters and use your limited 
fuel sparingly. You can see both a profile view of the spacecraft coming down and a plan 
view of the landing area. Land successfully and you get to view an animated walk on the 
moon. Nine levels of play provide a stiff challenge to the most skillful astronaut. Requires at 
least 16K of RAM. $14.95 

new! HANGMAN/MASTERMIND by Charles Finch. Two traditional games are broughtto life 
by Sorcerer graphics. HANGMAN has three different vocabulary levels for you to choose 
Irom. I n MASTERMIND, the computer selects a four-character code and you have to uncover 
it. These two games provide an enjoyable way for young people to develop their vocabulary 
and their logical reasoning ability. Written in BASIC. $11.95 

QS SMART TERMINAL by Bob Pierce. Convert your Sorcerer to a smart terminal. Used with a 
modem, this program provides the capability for you to communicate efficiently and save 
connect time with larger computers and other microcomputers. The program formats 
incoming data from time-sharing systems such as The Source for the Sorcerer video. 
Incoming data can be stored (downloaded) into a file in RAM. Files, including programs, may 
be saved to or loaded from cassette, listed on the video, transmitted out through your 
modem, or edited with an on-board text editor. Interfaces with BASIC and the Word 
Processor Pac. $49.95 

DPX*" (Development Pac Extension) by Don Ursem. Serious Z80 program developers will 
find this utility program to be invaluable. Move the line pointer upward. Locate a word or 
symbol. Change a character string wherever it occurs. Simple commands allow you to jump 
directly from EDIT to MONITOR or DDT80 modes and automatically set up the I/O you want 
for listings. Built-in serial driver. Stop and restart listings. Abort assembly with the ESC key. 
Save backup files on tape at 1200 baud. Load and merge files from tape by file name. 
Versions for 8K, 16K, 32K. and 48K Sorcerer all on one cassette. Requires the Sorcerer's 
Development Pac. $29.95 



Other utility programs: 

PLOT by Vic Tolomei. High res and low res modes $14.95 

SHAPE MAKER" by Don Ursem. An on-screen character maker $14.95 

DEBUG by Bob Pierce. Debug machine language programs $14.95 

SOFTWARE INTERNALS MANUAL by Vic Tolomei. A 64-page book $14.95 

Other game programs: 

MARTIAN INVADERS'" by James Albanese $14.95 

NIKE II'" by Charles Finch and Bob Broffel $11.95 

TANK TRAP by Don Ursem $11.95 

MAGIC MAZE'" by Vic Tolomei $11.95 

FASTGAMMON'" by Bob Christiansen $19.95 



QUTILny SOFTWARE 

6660 Reseda Blvd., Suite 105. Reseda. CA 91335 
Telephone 24 hours, seven days a week: (213)344-6599 




WHERE TO GET IT: Ask your nearest Sorcerer dealer to 
programs. Or, if you prefer, you may order directly from 
holders may telephone their orders and we will deduct $1 
sate for phone charges. Or mail your order to the address a 
sales tax. Shipping Charges: Within North America orders 
shipping and handling. Outside North America the charge 
is $5.00 — payable in U.S. currency. 
•The name "SORCERER" has been Irademarked by Exidy. Inc 



see Quality Software's Sorcerer 
us. MasterCharge and Visa card- 
from orders over $19 to compen- 
bove. California residents add 6% 
must include $1.50 for first class 
for airmail shipping and handling 



126 January 1981 © BYTE Publications Inc 



Circle 77 on inquiry card. 



reliably. The printer output itself, which is made up of 
blue or purple characters, is not recognized at all by the 
wand, and photocopies give erratic results. 

Even if the problems of color, contrast, and resolution 
could be solved, there would remain other impediments. 
The bar pattern for most of the instruction codes exceeds 
the capacity of the print buffer; what is more, with no 
means of summoning up operation codes from program 
memory, printing the bar-code representation of a pro- 
gram would necessarily entail manual translation. With 
the system in its present configuration, bar-code output 
from the printer does not seem to be practical, although it 
is tantalizingly close. 

The mere possibility of obtaining 

hard copy greatly enhances the 

utility of the calculator . . . 

The Printer 

The printer is easily the most engaging component of 
the HP-41C system. The mere possibility of obtaining 
hard copy greatly enhances the utility of the calculator, 
since it relieves the operator of the need to transcribe 
results as they become available. The printer for the HP- 
41C does more than that: it will reproduce anything that 
appears in the display and much else besides. 

The print mechanism is a thermal, dot-matrix one; 
24-character lines are printed on rolls of heat-sensitive 
paper about 6 cm wide. There is a standard set of 127 
characters, including full uppercase and lowercase 
alphabets, the ten numerals, a few Greek letters, and 
miscellaneous other symbols and punctuation marks. All 
characters can be printed in a standard 5 by 7 matrix or in 
a double-width format. A few of the standard calculator 
instructions trigger printing and, in addition, the printer 
has its own repertoire of about twenty-five instructions. 

Programs can be listed in their entirety, or a designated 
number of lines can be printed out; in either case, the 
listing shows the same mnemonics that appear in the 
display. The path followed by the calculator through a 
program being executed can be traced, providing a record 
of all instructions and operands; this is a useful facility 
when the program does not function as expected. The 
contents of the operand stack can be printed out with a 
single command; so can the contents of all allocated 
memory registers, or of a defined block of registers. In 
addition, assignments of nonstandard functions to the 
keyboard and the status of all flags can be listed. All of 
these functions can be executed manually or within a pro- 
gram. 

The most commonly invoked print functions are those 
that print the contents of the X register (roughly 
equivalent to an accumulator), the alpha register, or a 
print buffer. The variations offered by these instructions 
allow the output of a program to take almost any format 
within the physical capabilities of the printer. The main 
limitations are the time and space the programmer wishes 
to dedicate to format commands. It is easy to list a series 
of variable names, each followed by a colon or an equals 
sign and a value. Tabulating two or three columns of 
numbers so they line up vertically on their decimal points 

Circle 78 on inquiry card. ■■■► 




The MODEL 800 MST is certainly pleasing to look at, but its true beauty lies beneath the surface. A glimpse at its 
features reveals why it is rapidly becoming the most sought after printer in the world . . . 



Four standard interfaces: 

RS-232(15 baud rates) 

Centronics compatible parallel 

IEEE-488 

20ma current loop 
Six line densities: 64, 72, 80, 96, 120, 132 
100 CPS at all six densities 
Unidirectional or bidirectional printing 
Sixteen horizontal and ten vertical tabs 
Elongated characters in all six densities 
1920 character buffer 
Uses either perforated or roll paper 
Fully adjustable tractors to 9V2" 
Auto self-test 



• Up to 10 character fonts 

Standard 96 character ASCII 

User defined character font 

Provision for up to eight additional fonts 

• Dot resolution graphics in six densities 

• Variable line spacing control from to 64 dots in 
half-dot increments 

• Auto form-feed for any form length at any line 
spacing 

• Heavy-duty all aluminum chassis 

• 1 lOvac or 220vac, 50/60Hz. 

• 100 million character printhead 

• Measures only 15" wide, 3" high, and 11" deep 

• Weighs only 15 lbs. 



but maybe its most attractive feature is the price $699.00. 



baxe_ inc. 



W 



P.O. 

y — 



BOX 3548 FULL., CAL. 92634 / C7ia) 992-4344 



demands a somewhat larger investment of program 
memory and execution time. 

The dot-matrix print head is a single vertical row of 
print elements that sweeps across the paper forming 
characters as a series of columns (see table la). A special 
set of printer instructions brings this process under pro- 
gram control so that nonstandard characters can be 
created. Indeed, the printer reproduces any pattern that 
can be defined by a matrix 7 dots high and no more than 
40 dots wide. If the pattern fits in a 7 by 7 box, it can be 
treated as a special character, stored in a register, and 
called up as needed. In principle, a complete font could 
be built up in this way, although its usefulness might be 
somewhat impaired by the limited capacity of the print 
buffer: only 6 special characters per line can be printed. A 
more practical application is the creation of schematic 
symbols and markers, such as playing-card suits, chess 
pieces, or the phases of the moon (see table lb). 

Another capability of the printer is the plotting of 
graphs for any function that can be expressed in the form 
y = f(x). The graph is drawn under the direction of a 





(a) 






(b) 


STANDARD CHARACTERS 


SPECIAL CHARACTERS 


I JZ 


x g 


* *^ 


ci o: 




P 


r r 


i i- 


A A 


d a a 


»T 


♦ + 


\ I-. 


L' JU 


■ ■ ■ 


/ V 


f T 


1 .j. 


e e 


= llll ■». ?s 


C Q 


'— ' 


fl fi 


i A 


.-■.•-•■yz-'yz-':---j-yz-''S. 


M f=l 


o d 





o 6 


Z-i m -Z m -l--Z<-ZK-'Z-^-Z-^--l 





u u 


E ft 


fi 6ft 


j^$35?SS5S$i 


* # 


I £ 


i & 




?SS4SS5ftSSSii 


i ; 
v 3s 


l & 


§ # 


( £ 


1 1 1 1 1 1 


♦ ¥ ♦ ♦ 


) ;■ 


* * 


+ + 


.■ .■ 


V -x $ <? 


- - 


, . 


/ ..-' 


8 9 


sZ-^r 


1 1 


?. £ 


3 3 


4 4 


-W 


5 5 


6 6 


7 7 


8 8 


< W HI" H* 


9 9 




i j 


< < 




- = 


\ --.. 


? '? 


g fa 




a n 


B B 


C C 


n n 




E E 


F F 


G G 


H H 




I I 


J J 


K K 


L L 




r) M 


H N 





P P 




Q Q 


R R 


"^ ^ 


T T 




U U 


ti *■ i 1 


V, W 


- X 




Y ¥ 


7 ~7 


[ C 


\ % 




] ] 


t t 


_ 


T T 




a a 


b b 


c o 


d d 




8 ■=' 


f f 


9 "3 


ii h 




i i 


j J 


k k 


i 1 




n fi 


n n 


O 


p p 




i '3. 


r r 


i S 


t t 




U u 


V •-,' 


U 1.0 


s X 




7 V 


2 2 


if TV 


1 1 




■» -j- 


I s 


r I- 






Table 1: 


Character set as printed by the HP-41C printer. The 


standard character set, shown in table la, contains 127 let- 


ters, numbers 


and 


other symbols. About sixty of them, in- 


eluding 


the fu 


11 uppercase alphabet, 


can also be represented 


in a somewhat different form in the 


display of the HP-41C 


itself. Each character can be printed 


in a standard 5 by 7 dot 


matrix or in a 


double-width format. Special characters (table 


lb) can 


also be created by specifying the pattern of dots in 


each column < 


->f the character. 





program called PRPLOT (print plot), which is committed 
to read-only memory in the printer. When PRPLOT is ex- 
ecuted (see listing 1), it first asks the user to supply cer- 
tain information that determines the form of the 
graph, such as the range of x and y. It then calls on a 
named program, also supplied by the user, that for each 
given value of x must return a value f(x). The resulting 
graphs cannot compare to the product of an x,y plotter, 
but they can be run off quickly and are adequate for 
gauging the basic form and range of a function. PRPLOT 
can also be executed from within a program without the 
prompting for input values, and various parts of it can be 
called independently. 

Programming with Labels 

An organizing principle of programs for the HP-41C is 
that all references and transfers of control are made by 
means of labels. The name given to a program constitutes 
a global label, one that can be accessed from any point in 
program memory. By invoking the name, a program can 
be called as a subroutine and can even call itself, although 
there are limits to such recursion. 

Labels within programs are generally local, so that the 
same labels can be repeated in different programs without 
interference. Subroutine calls and branches can be made 
only to a label; there is no absolute addressing by line 
number. As a result, all programs and procedures within 
programs can be relocated at will. Lines can also be freely 
inserted or deleted without adjusting references 
elsewhere. 

Instructions that require an address or a numerical 
argument can be given it either directly or indirectly. The 
addressing modes are uniform for all memory operations, 
subroutine calls, branching, loop control, the setting, 
clearing, and testing of flags, and even such functions as 
setting the display format and determining the pitch of 
the beeper. A subroutine is called by the XEQ (execute) 
function, which must be followed by a local label or the 
name of a program. 

If the instruction is an indirect one (XEQ IND), the 
2-digit number that follows is interpreted as the register 
where the subroutine name or label will be found. Any 
register, including those of the stack, can hold the in- 
direct address. Subroutines can be nested six levels deep 
before the return address of the highest-level routine is 
lost. 

Conditional tests of numerical data include various 
combinations of "less than," "greater than," "equal to," 
and "not equal to"; alphabetic strings can also be com- 
pared, but only for equivalence. All the tests have the 
same format, in which a false result causes the instruction 
following the test to be skipped. Tests of flags (set or 
clear) employ the same scheme. The complement of fifty- 
six flags seems particularly generous. Eleven flags are 
completely unencumbered for use in programs; the rest 
control the status of the HP-41C and its peripherals, 
thereby affording the calculator a valuable amount of 
self-knowledge. 

Loops 

The control of loops in HP-41C programs is facilitated 
by two instructions that store all the needed information 
in a single register. The instructions, ISG (increment, skip 
if greater) and DSE (decrement, skip if equal), refer 



128 January 1981 © BYTE Publications Inc 



Circle 79 on inquiry card. 



STOP PLAYING GAMES 



HH3lililVJillii:ilKi7 



Corvus Transforms the Personal Computer 
into a Powerful Business Tool. 

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directly or indirectly to a register holding a number of the 
form nnnnn.tttcc. Here nnnnn is the number to be tested, 
ttt is the value against which it is tested, and cc is the 
amount by which nnnnn is incremented, or decremented. 
The compacted form is a convenience, although I find it 
odd that the incremented number has a range of up to 
99,999, whereas a jump must take place whenever it ex- 
ceeds 999. 

Other Programming Features 

The HP-41C cannot realistically be said to support 
structured programming, not as I understand the term. 
The rule that all procedures should have a single entry 
point and a single exit, which is one of the precepts of 
structured programming, cannot be observed without ex- 
treme awkwardness. On the other hand, the program- 
control structures of the HP-41C strongly encourage the 
composition of modular programs, where each procedure 
is a self-contained unit, small enough to be fully 
understood and capable of being tested independently. In 
a program longer than a few hundred lines, some such 
technique for imposing order is obligatory. 

In the end, the capabilities of the HP-41C can be ex- 
hibited best by real programs and their output. A few 
short utility routines and a longer program, called 
CHART, are given in listings 2 and 3. CHART, which in- 
cidentally shows off to good advantage the versatility of 
the printer, produces a bar graph, a form of display that 
is more appropriate for some kinds of data than the line 
graphs of PRPLOT. 



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The main program in CHART (listing 2), which is con- 
fined to the first 20 lines, is little more than a list of XEQ 
statements. It first prompts the user for needed informa- 
tion, then does some preliminary calculations and prints 
a header that will identify the graph. An external pro- 
gram (see listing 4) is then called once for each bar; it is 
expected to return a value defining the length of the bar 
and a label of not more than 4 characters. 

It is worth noting that the actual calculation of the bar 
length is a trivial operation. The bulk of the program is 
taken up with input and output routines, which are in- 
tended to minimize the burden on the user's memory and 
faculties of interpretation. A bar graph generated by the 
CHART program is shown for data on the distribution of 
digits obtained from the RDM LN pseudorandom- 
number generator; see listing 5. 

Next Generations 

What more can one ask for in a programmable 
calculator? Quite a lot; there is much to look forward to 
in the next generation. More memory is always near the 
top of such a wish list. One way of supplying it, which 
might be compatible with the present mainframe, would 
be in a double-density memory module. The entire ad- 
dress space could then be utilized without filling all the 
ports. 

The very existence of ports inspires thoughts of other 

Text continued on page 136 



Listing 1: Graph of the function (sin x)/x was drawn by 
PRPLOT, a program that resides in read-only memory in the 
HP-41C printer. The function itself is defined by a separate pro- 
gram (at bottom), which evaluates the expression each time it is 
supplied with a value of x and called PRPLOT. 





PLOT OF SIN/X 


■ 


{ <UHITS= 1.) i 


1 


1 <0HIT3= E-2.> •> 




-8.58 2.8E 




8. 88 

|_ 1 _ 


368 


z 


331 


z 




382 


z 




274 


I 




245 


* 




21b 


I 




137 


• 




158 




X 


138 




I 


181 




I 


-72 




I 


-43 




■ 


-14 




» 


14 




X 


43 




I 


72 




I 


181 




I 


138 




z 


158 




z 


187 


« 




216 


• 




245 


2 




274 






382 


X 




331 


I 




368 







8I*LBL "SIN/ 

82 RCL X 

83 SIH 

84 XOY 

85 / 

86 END 



130 January 1981 © BYTE Publications Inc 



Circle 80 on inquiry card. 




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BYTE January 1981 131 



Listing 2: A bar-graph program. CHART, the HP-41C program for generating bar graphs, is written as a series of modules. Thefirst 
of these prompts the user to supply certain initial information that will determine the form of the graph. An alternative entry point, 
CHARTP, is intended for occasions when the bar-graph routine is called from another program; this entry point bypasses the 
prompting. For each bar drawn, CHART calls on a user-supplied program, which must return two items, the value to be plotted in 
the X register and a label for the bar no more than 4 characters long in the alpha register. The bar is actually formed in subroutine 08 
out of a standard character and additional print columns for fine adjustment of the length. 



8WLBL "CHART" 
62»LBL .5 
03 XEQ 08 
84»LBL -CHflRTP- 

65 XEQ 81 

66 XEQ 82 

07 XEQ -BAR" 
88»LBL A 
89 XEQ 83 

10 XEQ 84 

11 XEQ 85 
12»LBL 38 

13 XEQ 67 

14 RCL 13 

15 INT 

16 XEQ 1,'IB 11 

17 XEQ 83 

18 I3G 13 

19 GTO 38 

20 XEQ 67 

21 GTO 50 



22»LBL 80 

23 CF 23 

24 -PGH NAME?" 

25 RON 

26 PROMPT 

27 FS? 23 
23 A3T0 11 

29 flOFF 

30 CF 22 

31 "NO. OF BARS?" 

32 PROMPT 

33 FS?C 22 

34 STO 12 

35 "Y KIN?" 

36 PROMPT 

37 FS?C 22 
33 STO 13 
39 "V MAX?" 
46 PROMPT 

41 FS?C 22 

42 STO -14 

43 -AXIS?" 

44 PROMPT 

45 FS? 22 

46 STO 15 

47 RTN 



48»L8L 61 
49 RCL 12 

58 1 

51 - 

52 1 E3 

53 / 

54 STO 18 

55 137 

56 RCL 14 

57 RCL 13 
53 - 

59 / 
66 "STO 



Initialization; can 
be executed from 
the keyboard by 
pressing "A." 



Main calculation and 
printing of bars. Calls 
a user program whose 
name is stored in 
register 11. 



Subroutine that 
prompts for inputs. 
In each case the 
prompting message 
appears in the 
display but is not 
printed. If no value 
is input following the 
prompt, the program 
assumes the value 
supplied on the previous 
run is still valid. 



16 



Set up register 
for looped calls 
to user program. 



Calculate coefficient 
relating /-axis 
scale to graph width 
of 137 columns. 



61 RCL 15 

62 XEQ 18 

63 STO 17 

64 5 

65 XOY 

66 X<=Y? 

67 ST- 17 
63 132 

69 XOY 
76 X>Y? 

71 ST- 17 

72 RTN 



73»LBL 82 

74 ODV 

75 All" 

76 "F" 

77 ACA 
73 SF 13 
79 "LOT OF 

86 ACA 

81 CF 13 

82 SF 12 
S3 RCL 11 

84 ACX 

85 CF 12 
36 PREUF 

87 RTN 



88+LBL 83 

39 SF 12 

98 

91 



ACA 



92 7 

93 ACCHR 

94 29 

95 SKPCOL 

96 T 

97 ACA 
93 125 
99 ACCHR 

186 CF 12 

161 PRBUF 

162 RTN 



103«LBL 04 

104 RCL 13 

165 ACX 

166 XEQ 11 

167 STO 16 
188 RCL 14 
169 XEQ 11 
118 ST+ 18 
111.144 

112 RCL 16 

113 - 

114 SKPCOL 

115 RCL 14 

116 ACX 



Calculate absolute 
position of axis; 
if beyond the range 
of the graph, axis 
is suppressed. 



Print identifying 

header: 

"Plot of 'PGM NAME' 



Print labels 
for X and Y 



Labels extrema 
of Y axis. 



117 ADV 

118 RTN 



119»L8L 85 




128 




121 STO 16 




122 RCL 17 




123 X=6? 




124 RTN 




125 119 




126 ACCOL 




127 RUN 




123 RCL 15 




129 XEQ 1! 




130 ST+ 16 




131 2 




132 / 

pi - 


Labels axis 


134 5 

135 X>Y? 

136 GTO 52 


within graph, 
if it has not 
been suppressed 


137 RUN 




133 132 




139 RCL 18 




149 - 




141 X<Y? 




142 GTO 52 




143 RUN 




I44+LBL 52 




145 I NT 




146 SKPCOL 




147 ST+ 18 




143 RCL 15 




149 ACX 




158 XEQ 12 




151 RTN 





152*LBL 87 

153 119 

154 ACCOL 

155 

156 STO 18 

157 XEQ 17 

158 XEQ 12 

159 RTN 



166«LBL 88 

161 ACA 

162 3 

163 SKPCOL 
164-RJJN 

165 XEQ 18 

166 X<=8? 

167 GTO 07 

168 127 

169 ACCOL 
178 RUN 
171 136 



Accumulates markers 
for the extrema points 
and the axis in spaces 
between bars. 



Master subroutine 
for accumulating and 
printing a bar. Checks 
if the length is zero; 
if so, executes LBL 07. 
Checks if the length is 



Listing 2 continued on page 134 



132 January 1981 © BYTE Publications Inc 



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TERM: A complete intercommunications package for linking your com- 
puter to other computers, Link either to other CP/M computers or to large 
timesharing systems. TERM is comparable to other systems but costs 
less, delivers more and source is provided on discette! With TERM you 
can send and receive ASCII and Hex files (COM too, with included conver- 
tion program) with any other real time communication between users on 
separate systems as well as acting as timesharing terminal. 

• Engage/disengage printer • error checking and auto retry 

• terminal mode for timesharing between systems 

• conversational mode • send files • receive files 
Requires: 32K CP/M 

Supplied with user manual and 8080 source code: $150,00 
Manual alone: $15.00 



INTERCOMPUTER COMMUNICATIONS? 



ta 


".'.'• "''"■■■ ' ■■:•'■■ .!;*€? -'.' ."' ■ ,j/ 




ANALIZA: An amazingly accurate 
simulation of a session with a 
psychiatrist. Better than the famous 


r v 


■ :: . 


"ELIZA" program. Enlightening as 


.:: 


■T : 


well as fun. An excellent example of 
Artificial Intelligence. 
Requires: 48K CP/M. CBASIC2 


M 


P 


Cost: $35,00 


:':': 


;i::ii;;;;;i::.j entertainment }■••::!;;;;;;•:: 


s 



H< 


'..'' ..,.'■' 'J <■ .... : -- ■'■'. '...' '■:'- - '.'. ■'■ 


ft 


CI. 1 


Z8000CROSS ASSEMBLER: Supports 






full Z8000 syntax, segmented and 






unsegmented mode, full 32- b 1 1 


.-. 


V. 


arithmetic, hex output, listing output, 


: : : 


'■•/ 


"downloader". 


v. 




Requires: 56K CP/M $500.00 
1 year maintenance $300.00 


'._:_;' 


:' i'i 

1 


manual alone $ 50.00 


k 


Ii;S""'ii!:R:!ii| zaoootoo! |::i"i::> :; '":i::ir 

I ti 'L- ,1 -i — -±^ a- 



ENCODE/DECODE: A complete software security system for CP/M. 
Encode/Decode is a sophisticated coding program package which trans- 
forms data stored on disk into coded text which is completely unrecog- 
nizable. Encode/Decode supports multiple security levels and passwords. 
A user defined combination (One billion possible) is used to code and 
decode a file. Uses are unlimited. Below are a tew examples: 

• databases • payroll files • programs • tax records 

Encode/Decode is available in two versions: 

Encode/Decode I provides a level of security suitable tor normal use. 
Encode/Decode II provides enhanced security for the most demanding 
needs. 
Encode/Decode I: $50.00 Encode/Decode 11:5100.00 manual alone: $15.00 



^ SOFTWARE SECURITY ^ 



On line "Help" system provided with every program package. 



SuperSoft 

First in Software Technology 



Circle 82 on Inquiry card. 



CP/M Formats: 8" soft sectored, 5" Northstar, 5" Micropo- 
lis Mod II, Vector MZ, Superbrain DD/QD 



All Orders and General Information: 

SUPERSOFT ASSOCIATES 

P.O. BOX 1628 

CHAMPAIGN, IL 61820 

(217)359-2112 

Technical Hot Line: (217) 359-2691 

(answered only when technician Is available) 

CP/M REGISTERED TRADEMARK DIGITAL RESEARCH 



Listing 2 continued: 

172 X<=Y? 

173 GTO 89 

174 RHH 

175 STO 18 

176 XEQ 15 

177 ROH 

178 KEG 16 

179 127 
188 RCCOL 

181 XEQ 17 

182 XEQ 12 
133 RTH 



134 
185 
136 
187 
133 
189 
198 
191 
192 

19: 
194 
195 
196 

197 
193 
199 
288 
281 
282 
283 



♦LBL 89 
STO 18 
XEQ 15 
RBH 

XEQ 16 
127 
flCCOL 
ADV 
RTH 

♦LBL 15 

I 

X>Y? 
RTH 

RTH 
31 

flCCKR 
RDM 

GTO 15 



greater than the maximum; 
if so, executes LBL 09. 
Otherwise, the bar is 
built up by LBL 15 
and LBL 16. 



Special routine for 
a bar that must fill 
the entire width of 
the graph. 



Accumulates the maximum 
integer number of gray-tone 
characters (standard char- 
acter 31) that will fit in 
the bar. 



284*LBL 16 




285 1 




286 X>Y? 




287 RTH 




288 X=Y? 




289 RTH 




210 42 




211 flCCOL 


Finishes a bar by 


212 RDH 


accumulating individual 


213*- 


columns until actual 


214 1 


length eguals specified 


215 X>Y? 


length. 


216 RTH 




217 X=Y? 




213 RTH 




219 35 




228 RCCOL 




221 RDH 




222 - 




223 GTO 16 




224»LBL 17 




225 RCL 18 




226 1 




227 + 




223 RCL 17 




229 X*8? 


Inserts space from 


238 X<=Y? 


end of bar to maximum Y 


231 RTH 


then adds a marker for 


232 STO 18 


maximum Y 


233 XOY 




234 - 




235 SKPCOL 




236 119 




237 flCCOL 




233 RTH 





239*LBL 


18 


240 


RCL 


13 


241 


- 




242 


RCL 


16 


243 


* 




244 


FIX 


8 


245 


RND 




246 


FIX 


c 


247 


RTH 




248 


►LBL 


11 


249 


BBS 




258 


sf ; 


IT 


251 


LOG 




1CA 

C-JC 


cf : 


e 


253 


IHT 




254 


5 




L.JJ 


+ 




256 


7 




257 


* 




258 


RTH 




259»LBL 


12 


268 


135 




261 


RCL 


18 


262 


- 




263 


SKPC 


OL 


264 


119 




265 


flCCOL 


266 


ADV 




267 


RTH 




268*LBL 


58 


269 


ADV 




278 


ADV 




271 


BEEF 




272 


EHB 





Calculates the length 
of the bar. 



Calculates width of 
a number (eg: axis or 
extrema labels) in number 
of columns. 



Adds space to fill out a 
line, other than a line with 
a bar, then prints a Y - 
maximum marker. 



Beeps to mark finish. 



RACET SORTS - RACET UTILITIES - RACET computes - RACET SORTS - RACET UTILITIES - RACET computes — RACET SORTS - RACET UTILITIES - RACET computes - 



HARD DISK MULTIPLEXOR 
F0RTHETRS-80*Modll 

NOW YOU CAN HAVE THAT LARGE COMMON DATA BASE! ! 

• Allows up to 4 Mod ll's to connect to a single controller — up to 4 hard disk 
drives per controller. Users may access the same file simultaneously (first-come 
first-served). 

• Uses Cameo controller and standard 10-megabyte cartridge (hard) disk drives 
along with RACET Hard/Soft Disk System (HSD) software. 

• Access times 3 to 8 times faster than floppy. Mixed floppy/hard disk operation 
supported. 

• Compatible with your existing TRSDOS programs — you need only change 
filenames! All BASIC statements are identical. 

• A single file may be as large as one disk. Alternate mode allows 24-million 
byte record range. Directory expandable to handle thousands of files. 

• Includes special utilities — XCOPY for backup and copies, XPURGE for multiple 
deletions, DCS directory catalog system, and Hard Disk Superzap. FORMAT 
utility includes options for specifying sectors/gran, platters/drive, logical 
disk size, etc. 

HARD DISK DRIVES CONTROLLER $5995 RACET HSD Software $400 
Call for multiuser pricing. Dealers call for OEM pricing. 

BASIC LINK FACILITY 'BUNK' $25 Mod I, $50 Mod II 

Link from one BASIC program to another saving all variables! The new program 
can be smaller or larger than the original program in memory. The chained program 
may either replace the original program, or can be merged by statement number. 
The statement number where the chained program execution is to begin may be 
specified! (Mod I Min 32K 1-disk) 

INFINITE BASIC (Mod I Tape or Disk) $49.95 

Extends Level II BASIC with complete MATRIX functions and 50 more string 
functions. Includes RACET machine language sorts! Sort 1000 elements in 9 
seconds! ! Select only functions you want to optimize memory usage. 

INFINITE BUSINESS (Requires Infinite BASIC) $29.95 

Complete printer pagination controls — auto headers, footers, page numbers. 
Packed decimal arithmetic — 127 digit accuracy +, -,*,/. Binary search 
of sorted and unsorted arrays. Hash codes. 



BASIC CROSS REFERENCE UTILITY (Mod II 64K) $50.00 

SEEK and FIND functions for Variables, Line Numbers, Strings, Keywords. 'All' 
options available for line numbers and variables. Load from BASIC — Call with 
'CTRL'R. Output to screen or printer! 

DSM $75.00 Mod I, $150.00 Mod II 

Disk Sort/Merge for RANDOM files. All machine language stand-alone package for 
sorting speed. Establish sort specification in simple BASIC command File. Execute 
from DOS. Only operator action to sort is to change diskettes when requested! 
Handles multiple diskette files! Super fast sort times — improved disk I/O times 
make this the fastest Disk Sort/Merge available on Mod I or Mod II. 

(Modi Min 32K 2-drive system. Mod II 64K 1 -drive) 
UTILITY PACKAGE (Mod II 64K) $150.00 

Important enhancements to the Mod II. The file recovery capabilities alone will pay 
for the package in even one application! Fully documented in 124 page manual! 
XHIT, XGAT, XCOPY and SUPERZAP are used to reconstruct or recover date Irom 
bad diskettes! XCOPY provides multi-file copies, 'Wild-card' mask select, absolute 
sector mode and other features. SUPERZAP allows examine/change any sector on 
diskette include track-0, and absolute disk backup/copy with I/O recovery. DCS 
builds consolidated directories from multiple diskettes into a single display or 
listing sorted by disk name or file name plus more. Change Disk ID with DISKID. 
XCREATE preallocates files and sets 'L0F' to end to speed disk accesses. DEBUGII 
adds single step, trace, subroutine calling, program looping, dynamic disassembly 
and more!! 

DEVELOPMENT PACKAGE (Mod II 64K) $125.00 

Includes RACET machine language SUPERZAP, Apparat Disassembler, and Model 
II interface to the Microsoft 'Editor Assembler Plus' software package including 
uploading services and patches for Disk I/O. Purchase price includes complete 
copy of Editor Assembler + and documentation for Mod I. Assemble directly into 
memory, MACRO facility, save all or portions of source to disk, dynamic debug 
facility (ZBUG), extended editor commands. 

C0MPR0C(Modl — Disk only) $19.95 

Command Processor. Auto your disk to perform any sequence of instructions that 
you can give from the keyboard. DIR, FREE, pause, wait for user input. BASIC, No. 
of FILES and MEM SIZE, RUN program, respond to input statements, BREAK, 
return to DOS, etc. Includes lowercase driver, debounce, screenprint! 



CHECK, VISA. M/C COD, PURCHASE ORDER 
TELEPHONE ORDERS ACCEPTED (714) 637-5016 



•TRS-BO IS A REGISTERED TRADEMARK 
OF TANDY CORPORATION 



£T RACET COMPUTES -Z£ 



702 Palmdale, Orange, CA 92665 

RACET SORTS - RACET UTILITIES — RACET computes — RACET SORTS - RACET UTILITIES — RACET computes — RACET SORTS — RACET UTILITIES — RACET computes - 



134 January 1981 © BYTE Publications Inc 



Circle 83 on Inquiry card. 



Circle 84 on inquiry card. 



Accounting 



Thousands of SoftwareHows'"users agree — SoftwareHows 
products set a new standard of excellence for solution-oriented 
software. Instant installation for your system, powerful "word 
processing-like" editing facilities and consistent operating 
features make this SolutionWare'" the only serious choice for 
your needs. 

Why settle for a piece 
when you can have 
the whole pie?! 



At last! An integrated system of business 
software ideal for you! 

How often have you purchased software 
only to be disappointed by its features or 
frustrated by the inability of the different 
programs to work together? Are you tired 
of entering the same data into your Pur- 
chase Ordering System when a part is or- 
dered ,into Inventory when it arrives, Payabje* 
when it's invoiced and General Ledger when 
it's paid for? Can you easily link your Account- 
ing Data Base with your word processing software 
to create personalized letters, reports, notices and 
announcements?* Does your Point of Sale, Order 
Entry software also save a keyed file which may later 
be Sorted for over 60 customer characteristics and used 
to generate personalized sales literature? 

If you don't like your answers to these questions, your accounting 
software is costing you money! 

The Data Base Integration™ System from SoftwareHows "does all 
this and much more! This newest software product offers the 
perfect blend of performance, price and flexibility. Every single 
transaction feeds your master records. This common data base 
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data base is unique. You'll be amazed at how much better you'll 
understand the operation and cash flow of your business! And 
better understanding means better planning — and higher profits 
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The Data Base Integration System is built around the basic four 
accounting tools: General Ledger provides those all important 
balance sheets and income statements, Accounts Receivable and 
Payable take care of invoice control in a jiffy, while Payroll with 
Cost Accounting does your payroll and provides cost effective- 
ness data. All packages fully interact and are self-checking. The 
amazing Order-Right '" order entry system and MicroDaSys In- 
ventory, give you one of the most complete sales management 
and material requirements systems available. Output is processed 
with lightning speed and meticulous accuracy: invoices, shipping 
labels, charge slips and COD tags. Orders automatically interact 
with Inventory and Receivables. If your stock is too low, Inventory 
recommends the best source of supply and approximate prices to 
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receiving department verifies receipt and the invoice is trans- 
ferred to Accounts Payable. 

The Data Base Integration Business System is $2500. And that's 
for all seven packages! Now there's a deal too good to pass up! 
It includes over 1500 pages of user documentation, and a supply 
of computer forms. With our unique DBI Installation Program, 
getting the complete package up and running on your system 
is a breeze. Best of all, complete CBASIC source code is included 
with every CBASIC package. Current disk formats include 8" soft- 
sectored, 5" hard- and soft-sectored. 

Call or Write for the SolutionWare '" to meet 
your software needs — today! 




Order-Right" 



Inventory 



I I Ask your dealer why our 

business software is the best! 

I I A Complete 200 page Overview of all 

SoftwareHows SolutionWare is yours 
for just $75, refundable with purchase. 





TM 



a division of MicroDaSys 



PO Box 36275 Los Angeles, CA 90036 
(213)731-0876 TWX:9 10-32 1-2378 



Text continued from page 130: 

peripheral devices. A cassette recorder could provide 
mass storage and would make feasible operations on 
large blocks of data. An x,y plotter could be driven very 
efficiently by the HP-41C, albeit at a leisurely pace. With 
a fairly simple interface, it should be possible to connect 
the calculator to a computer system. The likelihood that 
any of these products will ever be forthcoming is un- 
known. It is probably too much to ask that Hewlett- 
Packard release technical information on the signals 
available at the ports so that others could develop plug- 
compatible devices. Some intrepid experimenter with a 
logic probe may do it anyway. 

There are a few gaps in the instruction set of the HP- 
41C that should not be perpetuated in future calculators. 
For example, there are tests for x < y, for x < y and for 
x > y, but there is no test for x > y. Of course, any 
desired logic function can be fabricated out of the existing 
instructions, but the programmer should not have to go 
to that trouble and should not have to remember which 
of the tests is the missing one. 

The most fundamental defect in the architecture of the 
HP-41C, inadequate numerical precision, is a serious 
flaw indeed. Numbers are represented, both internally 
and in the display, with 10 decimal digits; there are no 
guard digits. As a result, inaccuracies are quite often in- 
troduced into the least-significant digit. For example, 
(■s/2) 2 is evaluated by the calculator as 1.999999999. For 
operations on some data, the corruption goes still deeper 
and 2 or 3 digits become suspect. There is something ab- 
surd about the world's fanciest calculator not being able 




NOW. . .Continuous Checks 

That Can be Used With or Without Your Computer! ! 
The Best in A Home Checking System 

That's right. Continuous Checks in a 3-to-a-page 
desk set design that can be computer printed or 
handwritten - just as you now do your present 
home checks. 

VERSATILE 
Our checks are not a high-volume business form 
adaptation. They're especially designed for the 
home or low volume user. Now, you don't have 
to change your check writing habits just to use 
your computer. 



THOUGHTFUL FEATURES 

Programming? Easy. All stub and check informa- 
tion is on the same line. No need to change 
tractor width either. Our checks are standaru 
916" width for tractor feed printers. 

COMPLETE HOME SYSTEM 

When you've iinished printing your monthly 
checks on your computer, store your checks and 
stubs in our attractive Data Ring Binder Check- 
book. Later, if you have a few checks to write 
there's no need to load them into a printer - just 
write a check right there at your desk as shown 
above. 

And, you can mail your checks in our dual 
windowed envelopes to eliminate addressing 
chores. 

136 January 1981 © BYTE Publications Inc 



UNIQUE 

You won't find checks like these at any bank or 
forms company. Even so, our special small 
quantity printing process will give you quality 
and appearance equal to any check supplier. 
Color co-ordinated imprinting is standard on 
blue, grey, tan, or green checks. 
Standard imprinting and encoding is as shown 
above (logos and multi-color printing are 
optional). 

Our prices are reasonable too. Two Hundred 
checks are just S29.95 (envelopes $11.95}. 
Five Hundred checks are $49.95 (envelopes 
$23.95). Data Ring Checkbooks are only $5.95. 

Special "ORDER NOW" Offer 
If you order now, we'll send you a checkbook 
FREE. You'll save $5.95. Just enclose a voided 
check (for encoding information) with your 
payment. (VISA - MasterCharge orders must 
show signature, expiration date, and account 
number). Or, send today for samples (sorry, we 
can't make this free offer on requests for 
samples) To: 



to give results accurate to more than seven or eight 
decimal places. 

Actually, a subsidiary problem is more serious than 
that. Conditional tests on data are carried out on the full 
10-digit representation. Consequently, a test that effec- 
tively asks "Is (V2) 2 equal to 2?" will give a false result, 
which can lead a program far astray. 

Listing 3: Utility routines for the HP-41C. These two routines 
are the kinds of programs that can remain in memory as 
resources to be drawn on by other programs, somewhat like 
macro instructions in an assembly language. BAR simply prints 
a heavy bar across the width of the paper to separate different 
kinds of information. TAB handles the spacing of numbers to be 
printed in vertical columns. It must be supplied with the number 
to be printed (in the X register) and the number of character 
spaces to be measured from the present position in the line of 
print to the decimal point. TAB was employed in formatting the 
random-number data in listing 2. 



81+L8L "BfiR" 
82 SUV 
93 .823 
84 31 
85+LBL 61 
96 OCCHR 
67 I3G Y 
93 GTO 81 
89 FRBUF 
18 BDV 

11 flDV 

12 END 



SYNERGETIC 
SOLUTIONS 



4715 SHEPHERD RD. 

MULBERRY, FL 

33860 



01»LBL ■ 


82 


BBS 


S3 SF 25 


84 LOG 


85 


CF 25 


86 


X<=8? 


07 


CLX 


88 


INT 


89 


1 


IS 


+ 


11 


RCL X 


12 


3.1 


13 


/ 


14 


hit 


15 


+ 


16 


CHS 


17 


+ 


13 


SKPCH 



TfiB" 



19 END 



Listing 4: Random-number routines for the HP-41C. These two 
random-number generators, standard coding exercises for pro- 
grammable calculators, both calculate a pseudorandom real 
value, then select a single pseudorandom digit for return to the 
calling program. RDM LC employs the standard linear- 
congruential method, which has virtues and failings that are 
well understood. In this example, R n * , is equal to [24,298R„ + 
yy^yllmod 199,017. 

RDM LN is an algorithm the author stumbled upon but has 
not seen in the literature. R„ t , is defined as 1/ln R„. Experimen- 
tal runs of up to several thousand iterations have given good 
results, but the behavior of the algorithm is not understood. A 
sample test is shown in listing 5. 



9ULBL "RDM LN" 

02 RCL 28 

03 HBS 

04 LN 
85 1/X 

96 STO 20 
87 1 E3 

08 * 

09 FRC 
18 18 

11 * 

12 INT 

13 A8S 

14 END 



81»LBL "RDH LC" 

02 RCL 28 

03 24298 

04 * 

05 99991 

86 + 

87 199817 

08 MOD 

09 STO 28 
18 1 E3 

/ 

12 FRC 

13 10 

14 * 

15 INT 

16 END 



11 



Circle 85 on Inquiry card. 



Look 




's happened to 



HIPL0T 



TM 



$1,385- 




It's grown into a complete 
family of quality low cost digital plotters 



In just two short years, The 
HIPL0T has become the most 
popular digital plotter among 
small systems users. With a 
record like that, what can we do 
for an encore? WE'VE IN- 
TRODUCED A COMPLETE LINE 
OF HIPL0TS...with a model 
suited for just about every plot- 
ting application. 

The HIPL0T DMP Series is a 
new family of digital plotters 
with both "standard" and "in- 
telligent" models available with 
surface areas of 8 1 /2" x 11" (DIN 
A4) and 11" x 17" (DIN A3). For 
the user needing a basic reliable 
plotter, we have the "old stan- 
dard" DMP-2 (8 1 / 2 " x 1 1 ") and the 
"new standard" DMP-5 (11" x 
17"). For those needing a lit- 
tle more capability, there are 
the DMP-3 (8V2" x 11") and 
the DMP-6 (11" x 17")-both 



TM HIPLOT and DM/PL are Trademarks 
of Houslon Instrument 



Yes, they are UL listed! * 

microprocessor controlled and 
providing easy remote position- 
ing of the X and Y axes (perfect 
for the OEM). For those who 
want this intelligence plus the 
convenience of front panel elec- 
tronic controls, we've provided 
the DMP-4 (8 1 /2" x 11") and the 
DMP-7(11" x 17"). 

The "standard" plotters come 
complete with an RS-232-C and 
a parallel interface. The "intel- 
ligent" DMP plotters accept data 
from either an RS-232-C or Centronics 
data source. For the "standard" plot- 
ters, software is available from 
our ever expanding "Micrographic 
Users Group." The "intelligent" 
HIPLOTs use our exclusive 
DM/PL™ language which min- 
inimizes plot software to a 
fraction of that normally as- 

houston instrument 

GRAPHICS DIVISION OF 

BAUSCH&LOMB 



Circle 86 for literature 

Circle 87 to have representative call 

sociated wth digital plotting. 

With the new DMP Series, 
high quality digital plotting can 
now be a part of your system. It 
just doesn't make sense to be 
without this valuable tool when 
there is a DMP plotter with the 
plot size, speed and capabilities 
that are exactly tailored to your 
specific needs. ..and your 
budget. 

Prices for the DMP series 
range from $1,085* to $1,985*. 

For complete information con- 
tact Houston Instrument. One 
Houston Square, Austin, Texas 
78753. (512) 837-2820. For rush 
literature requests, outside Texas 
call toll free 1-800-531-5205. For 
technical information ask for 
operator #5. In Europe contact 
Houston Instrument, Rochester- 
laan 6, 8240 Gistel, Belgium. 
Telephone 059/27-74-45. 



'U.S. suggested retail prices only. 
DMP 2, 3 and 4 UL listed 
DMP 5, 6 and 7 UL listing pending 



DELIVER! || 

n VANDATA y 

Business Software <zj 



Before you buy the programs that your company is going to 
depend on for its accounting, ask the following questions: 

Do I get the source (Don't settle for less. 

code? You cannot make the 

smallest change without it.) 

Is it well documented? (The Osborne documen- 
tation is the best.) 

Is it fully supported? (If not, why not? What are 
they afraid of?) 

The Osborne system is the industry standard accounting 
package, with literally thousands of users. We offer an en- 
hanced version of that package that will run on most systems 
without recompiling. 

CRT INDEPENDENCE. The original programs were 
designed to run on a Hazeltine terminal. To use a different 
CRT, you had to modify and test two modules — and recom- 
pile every program! With the Vandata package, you simply 
pick your CRT from a menu and run. 

FILE/DRIVE MAP. The original package had all data files 
on the same drive as the programs. Ours allows you to 
dynamically specify the drive assigned to each file. In fact, you 
can change the drive assignments whenever you wish, to ac- 
commodate expanded file sizes or new hardware — all 
without recompiling! 

INTEGRATION. The original AR and AP systems had to 
be changed and recompiled to feed journal entries to GL. Our 
installation program eliminates this hassle. It simply asks you if 
you want the systems integrated, and what your special ac- 
count numbers are. 

SPEED. The original programs used a binary search to ac- 
cess the GL account file. We use an enhanced technique that 
greatly cuts down on disk accesses, thus speeding up account 
lookups significantly in the GL, AR and AP systems. 

BUGS. We have corrected a number of bugs in the original 
programs. If you find a bug in our programs, we'll fix it — and 
send you a $20 reward! Our users are sent bug fixes in source 
form. 

MORE! We have made many minor enhancements, and 
fixed many minor problems. We are committed to the ongoing 
support of our package. Vandata has been an independent 
software supplier for over seven years. Quality and support are 
our way of doing business. 

General Ledger with Cash Journal . . $95 

Accounts Receivable $95 

Accounts Payable $95 

Payroll with Cost Accounting $95 

• All Four Packages (GL, AR, AP, PR) $295 

Magic Wand (Super Word Processor!!) $345 

Pearl Level III (best prog, tool available) $645 

CBASIC-2 $110 

TRS-80® MODIICP/M® 2.2 (Pickles & Trout) $185 
H89/Z89 CP/M® 2.2 (Magnolia Microsystems)$249 

Formats: Sid. 8". 5" NorthStar DD. TRS-80 MOD II", H89/Z89 Manuals lor 
GL, AR/AP. and PR are not included in price — add $20 per manual desired 
(AR/AP are in one manual). CP/M- ! and CBASIC-2 required lo run accounting 
software Users must sign licensing agreement Dealer inquiries invited. 

To order call: (206) 542-8370 
or write: VANDATA 

17541 Stone Avenue North 

Seattle, WA 98133 



CP/M® is a registered trademark ot Digital Research. 
TRS-80® is a registered trademark ot Radio Shack, Inc. 



Listing 5: Bar-graph results of the CHART program, given in 
listing 2. The graph represents pictorially the distribution of the 
10 digits in a sample of 2500 pseudorandom numbers. The 
numbers were generated by another program, RDM LN (shown 
in listing 4), with the bookkeeping done by a third program. 



Tesi of 


• 


RDM LN" 


Plot of "RANDOM" 


Nufiber 


3f 


trials 2538 


mmimnmmmmi 


Seed = 


1 


234567890 


V.l Y-» 


uiuu 


mu 


286.80 389.88 








! 258.00 








mMMMM 1 


DIGIT i 


1 1 








<l>SIfSIHS3l?3 


MEAN = 




25S.08 


1 1 
1 i 

<2>liIiIBI! ! 


<9> = 




237. 


1 1 
1 1 


<1> = 




259. 


<3>aiIIS 1 


<2> = 




234. 


f 1 


<3> = 




22S, 


<4>mnsiinia 


<4> = 




256. 


i i 

i i 


<5> = 




265. 


<5>IM«IIiiI.«H 


<6> = 




268. 


1 1 
1 1 


\ I f ~ 




251. 


<6)IKiIII!III£ifII 


/0\ ~ 




259. 


1 1 


<9> = 




243. 


<7>fiSlllIlli ! 

1 I I 
i I I 

<3>BIISSP*i«l : 


RUNS OF 


d 


211. 


I 1 1 


RUNS OF 


3 


14. 


<9>liiiIIIH 1 1 


RUNS OF 


4 


3. 


i i I 


RUNS OF 


e 
J 


8. 





STATISTICS 

CHI SQUARED = 6.3248 

HIGH/LOW = 1.8593 

ODD/EVEN = 8.9936 

ISISIlIIIIillllilllilHI 



It is easy to imagine that some programmable 
calculator evolved from the HP-41C would have instruc- 
tions much like those of a higher-level language. Having 
introduced named programs, the next obvious step is 
named variables, which would relieve the programmer of 
much tedious worry over memory allocation. Let the 
machine keep track of where the numbers are; it does so 
better than people can. The existing conditional tests, 
which act directly on particular registers, might be recast 
as a more general if . . . then . . . else construction, 
employing the named variables. Also, do . . . while and 
repeat . . . until commands would be a welcome addi- 
tion; indeed, the loop-control instructions of the HP-41C 
already come close. 

One essential capability must be added to the 
calculator before such higher-level commands can be 
made available. A higher-level language is a program 
whose output is another program, and so it is necessary 
that instructions be allowed to operate not only on data 
but also on other instructions. In this context, it seems 
significant that the inability of a calculator to alter its 
own instructions is what most clearly distinguishes 
calculators from computers. ■ 



138 January 1981 © BYTE Publications Inc 



Circle 88 on inquiry card. 




INVEST IN PRODUCTIVITY 



Are you responsible for introducing modern 
office systems into your organization? 

Is your department going to be a user of such 
systems? 

Do you design, plan, make, or market such 
systems? 

If so, you should plan now to attend the second 
annual Office Automation Conference in Houston, 
Texas, March 23-25. 

More than a showcase for the latest office auto- 
mation equipment, the Conference provides a 
unique forum in which you can learn from experts 
how to harness and integrate today's worksaving 
devices for maximum gains in productivity 

In addition to 150 informative exhibits, you'll be 



able to attend over 50 special learning sessions. 
Sessions covering topics as diverse as: Feasibility 
Studies. ..Organizational Impact. ..Electronic Mail... 
Teleconferencing.. .Merger of Voice with Text and 
Data... State of the Art in Word Processing. 

Don't miss this opportunity to see and hear 
what's new in office automation and turn what you 
learn into greater productivity for you. 

For Conference information, call or write Office 
Automation Conference c/o AFIPS, PO. Box 9659, 
1815 N. Lynn Street, Arlington, VA 22209 (703)558-3610. 

For discount air fares, airline reservations, hotel 
and show information, or to pre-register, call toll-free 
(800) 556-6882. 

See you in Houston! 



THE 1981 OFFICE AUTOMATION CONFERENCE 
HOUSTON, TEXAS MARCH 23-25 



Circle 244 on inquiry card. 



BYTE January 1981 139 



No.18 

Software with 
full support 

Purchasing our software is just the 
beginning. We then back it up with 
professional support: 
■ Subscription to "LIFELINES" for automatic 
notifications of revisions! ■ Update service for 
software and documentation! ■ Telephone 
Hotline! ■ Overseas software export service! 

AM Lifeboat programs require CP/M, unless otherwise stated. 



ilinull/ Alor 



Munutl / Al 



^ 



LJCP/M* FLOPPY DISK OPERATING SYS- 
TEM— Digital Research's operating system 
configured for many popular micro-computers 
and disk systems: 

System Version Price 

Apple II* 2.x .. . .349/NA O 

SoftCard* with Z80 

Microsoft BASIC version 5 

with high resolution 

graphics 
North Star Single Density . . 2.x . . . .170/25 ® 
North Star Double/Quad . . . 2.x . . . .170/25 ® 

Durango F-85 2.x .. . .170/25 

iCOM Micro-Disk 241 1 1 .4 . . . .145/25 

iCOM 3712 for MITS 

88-2SIO Console 1.4 .. . .170/25 " 

iCOM 3712 for 3P+ S/MITS 

SIO Rev non-zero console 1 .4 . . . .170/25 " 

iCOM 3812 2.x .. . .225/25 ® 

JCOM3812 1.4... . 170/25 * 

iCOM 451 1/Pertec D3000 . . 2.x . . . .375/25 •+ 

Mils 3202/Altair 8800 1 .4 . . . .145/25 

Heath H8 + H17 1.4... .145/25 ® 

Heath H89 by Magnolia .... 2.x .. . .249/25 O 

Ohio Scientific C3 2.x .. . .200/25 

Ohio Scientific C3-C 2.x .. . .250/25 

Onyx C8001 Standard 2.x .. . ,250/25 

Onyx C8001 Enhanced .... 2.x .. . ,330/25 

TRS-80 Model I 1 .4 . . . .145/25 © 

TRS-80 Model II 2.x ,. . .170/25 

TRS-80 Model II + Corvus . 2.x . . . .250/25 
Processor Technology 

Helios II 1.4.... 145/25 

Intel MDS Single Density . . . 2,x 170/25 

Intel MDS Double Density , . 2.x . . . .170/25 

i jf Micropolis Mod I 2.x 200/25 ® 

k/Otv]* Micropolis Mod II 2.x ., . .200/25 ® 

'V Jl Mostek MDX STD 

Bus System 2.x... ,350/25 " 

HARD DISK OPTIONS (items with ®) when 
purchased with CP/M 2.X system. 

Corvus Add 80. 

Konan Phoenix Add 80. 

ICOM 451 1/Pertec D3000 Add 80. 

Software consists of the operating system, text 
editor, assembler, debugger and other utilities 
for file management and system maintenance. 
Complete set of Digital Research's documen- 
tation and additional Implementation notes in- 
cluded. Systems marked * and " include firm- 
ware on 2708 and 2716. Systems marked -In- 
clude 5440 media charge. Systems marked 
® require the special ® versions of soft- 
ware in this catalog. O includes hardware ad- 
dition to allow our standard versions of 
software to run under It. 
L.Z80 DEVELOPMENT PACKAGE-Consists 
® of: (1) disk file line editor, with global inter and 
® Intra-line facilities; (2) Z80 relocating assem- 
bler, Zllog/Mostek mnemonics, conditional as- 
sembly and cross reference table capabilities; 
(3) linking loader producing absolute Intel hex 

disk file $95/520 

DZDT— Z80 Monitor Debugger to break and 

'" examine registers with standard Zilog/ 

© Mostek mnemonic disassembly displays. S35 

when ordered with Z80 Development 

Package S50/S10 

AVOCET SYSTEMS 

D XASM-68— Non-macro cross-assembler with 
nested conditionals and full range of pseudo 
operations. Assembles from standard Motorola 
MC6800 mnemonics to Intel hex . , ,S200/$25 

□ XASM-65-As XASM-68 for MOS Technology 
MCS-6500 series mnemonics S200/S25 

□ XASM-4B- As XASM-68 for Intel MCS-4B and 
UPI-41 families S200/S25 

D X ASM-1 8- As XASM-68 for RCA 1 802 

$200/525 

Ll'DISTEL— Disk based disassembler to Intel 
8080 or TDL/Xitan Z80 source code, listing and 
cross reference files, Intel or TDL/Xitan pseudo 

ops optional. Runs on 8080 S65/S10 

DDISILOG-As DISTEL to Zilog/Mostek 

® mnemonic files S65/S10 

© 

DSMAL/80 Structured Macro Assembler 
® Language — Package of powerful general 
purpose text macro processor ana SMAL 
structured language compiler. SMAL is an as- 
sembler language with IF-THEN-ELSE, 
LOOP-REPEAT-WHILE, DO-END. BEGIN- 
END constructs. Not compatible with CP/M 
version 2 or greater $75/51 5 



□ RAID — 8080/8085 debugging aid and general 
system utility program. Both a software 
emulator and real-time debug monitor. Fea- 
tures multiple breakpoints, symbolic input, 
symbolic display and altering of registers, built- 
in assembler & dis-assembler, tracing, single- 
stepping, memory protection, histograms, 
memory search, direct disk access. Requires 
ZP/W 



w 



32K CP/M 



.S250/S25 



PHOENIX SOFTWARE ASSOCIATES 

DPASM* — Z80 macro assembler, Intel/TDL 
© mnemonics. Generates Intel hex format or re- 
locatable code in either TDL Object Module 
format or PSA Relocatable Binary Module for- 
mat. Supports text insertion, conditional 
branching within macros, recursive macro calls 
and parameter passing $129/325 

□ EDIT— Character oriented text file editor. In- 
© eludes macro definition capabilities. Handles 

insertion, deletion, searching, block move, etc. 
for files of any length. Does not require a 
CRT. $129/$25 

□ PLINK'-Two pass disk-to-disk linkage edl- 
ffl tor/loader which can produce re-entrant, 

ROMable code. Can link programs that are 
larger than available memory for execution 
targeted on another machine. Full library 
capabilities. Input can be PSA Relocatable Bi- 
nary Module, TDL Object Module or Microsoft 
REL files. Output can be a COM file, Intel hex 
file, TDL Object Module or PSA Relocatable 

file $129/525 

D BUG* and ^BUG'— Z80 interactive machine 
©level debugging tools lor program develop- 
ment, BUG "has full mnemonic trace and In- 
teractive assembly (mnemonics compatible 
with PASM). Dynamic breakpoints and condi- 
tional traps while tracing (even through ROM!), 
^BUG is a subset of BUG and is used in mem- 
ory limited situations $129/$25 



DIGITAL RESEARCH 

□ MP/M- Installed for single density MDS-800. 
Multi-processing derivative of the CP/M op- 
erating system. Manual includes CP/M? 
documentation $300/$50 

□ MAC— 8080 Macro assembler. Full Intel macro 
©definitions. Pseudo Ops Include RPC, IRP, 

REPT, TITLE, PAGE, and MACLIB. Produces 
absolute hex output plus symbol table file for 
use by SID and ZSID (see below) ..$120/515 

□ SID— 8080 Symbolic debugger. Full trace. 
© pass count and breakpoint program testing. 

Has backtrace and histogram utilities. When 
used with MAC, provides full symbolic display of 
memory labels and equated values ,$105/515 
DZSID— ZB0 Symbolic debugger with all fea- 
ts tures of SID 5130/S15 

® 

□ TEX— Text output formatter to create paglnat- 
®ed, page-numbered and justified copy. Output 

can be directed to printer or disk . . .5105/515 

□ DESPOOL— Utility program to permit simulta- 
©neous printing from text (lies while executing 

other programs 5B0/S10 



□ tiny C— Interactive interpretive system for 
® teaching structured programming techniques. 

Manual Includes full source listings .$105/550 

□ BDS C COMPILER- Supports structures, 
® unions, 2 dimensional arrays, pointers, recur- 
© sion and overlays. Features optimized code 

generator, variable sized buffers for file I/O, and 
capability to produce ROMable code. Includes 
macro package to enable user to produce link- 
able modules with MAC (see under Digital Re- 
search). Floating point functions, full run-time 
package and machine code library sources 
provided. Linker, library manager and textbook 
included. Compiler lacks Initializers, statics, 
floats and longs $145/525 

□ WHITESMITHS C COMPILER-The ultimate 
©In systems software tools. Produces faster 
® code than a pseudo-code Pascal with more 

extensive facilities. Conforms to the full UNIX" 
Version 7 C language, described by Kernighan 
and Ritchie, and makes available over 75 func- 
tions for performing I/O, string manipulation 
and storage allocation. Linkable to Microsoft 
REL files. Requires 60K CP/M 5630/530 



MICROSOFT iMmtS'i/Moiw 

□ BASIC-80-Disk Extended BASIC. ANSI 
©compatible with long variable names. 
©WHILE/WEND, chaining, variable lenglh file 

records. MBASIC version 4.51 also included on 
disk 5325/525 

□ BASIC COMPILER— Language compatible 
© with BASIC-80 and 3-10 times faster execution. 
® Produces standard Microsoft relocatable bi- 
nary output. Includes MACRO-80. Also linkable 
to FORTRAN-80 or COBOL-80 code 
modules S350/525 

□ FORTRAN-80-ANSI 66 (except for COM- 
© PLEX) plus many extensions. Includes relocat- 
® able object compiler, linking loader, library with 

manager Also includes MACRO-80 (see 
below) $425/525 

□ COBOL-80-Level 1 ANSI 74 standard plus 
© most of Level 2. Full sequential, relative, and 
® indexed file support with variable file names. 

Powerful interactive, formatted screen handling 
with ACCEPT and DISPLAY verbs. Program 
segmentation for execution of programs larger 
than memory and CHAIN command with pa- 
rameler passing. Full support of CP/M version 
2 files. Includes MACRO-80 (see above), link- 
ing loader, and relocatable library manager. 
Requires 48K CP/M $700/$25 

□ M/SORT— Optional sort/merge capability for 
©COBOL-80 which conforms fully to SORT/ 

MERGE, Level II of the 1974 ANSI COBOL 
standard (except COLLATING SEQUENCE IS 
alphabet-name). Requires COBOL-80. Sold as 

an update to COBOL-80 $150/510 

COBOL-80 + M/SORT $825/$35 

□ MACRO-80-8080/Z80 Macro Assembler. 
© Intel and Zilog mnemonics supported. Relocat- 
®able linkable output. Loader, Library Manager 

and Cross Reference List utilities 
included S149/S15 

□ XMACRO-86 — 8086 cross assembler. All 
© Macro and utility features of MACRO-80 pack- 
age. Mnemonics slightly modified from Intel 
ASM86. Compatibility data sheet 
available S275/S25 

□ EDIT-80— Very fast random access text editor 
® for text with or without line numbers. Global and 

intra-llne commands supported. File compare 
utility included $89/515 

□ muSIMP/muMATH — muSIMP is a high level 
© programming language suitable for symbolic 

and semi-numerical processing implemented 
using a fast and efficient interpreter requiring 
only 7K bytes of machine code. muMATH is a 
package of programs written in muSIMP The 
package performs sophisticated mathematical 
functions, Keeps track of up to 611 digits. Per- 
forms matrix operations on arrays: transpose, 
multiply, divide, inverse and other integer pow- 
ers. Logarithmic, exponential, trigonometric 
simplification and transformation, symbolic dif- 
ferentiation with partial derivatives, symbolic in- 
tegration of definite and indefinite integrals, 
Requires 40K CP/M $250/$20 

□ muLISP-60— Microcomputer implementation 
© of LISP. The interpreter resides in only 7K bytes 

of memory yet includes 83 LISP functions. Has 
infinite precision integer arithmetic expressed 
in any radix from 2 to 36. muLISPSO includes 
complete trace facility and a library of useful 
functions and entertaining sample 
programs $200/515 



□ PASCAL/M* — Compiles enhanced Standard 
® Pascal to compressed efficient Pcode, Totally 

CP/M compatible. Random access files. Both 
16 and 32-bit Integers. Runtime error recovery. 
Convenient STRINGS. OTHERWISE clause on 
CASE. Comprehensive manual (90 pp, In- 
dexed), SEGMENT provides overlay structure. 
INPORT, OUTPORT and untyped files for arbi- 
trary I/O. Requires 56K CP/M. Specify 1) 8080 
CP/M, 2) Z80 CP/M. or 3) Cromemco 
CDOS 5175/520 

□ PASCAL/Z-Z80 native code PASCAL com- 
® pller. Produces optimized, ROMable re-entrant 
©code. All interfacing to CP/M Is through the 

support library. The package Includes compiler, 
relocating assembler and linker, and source 
for all library modules. Variant records, strings 
and direct I/O are supported, Requires 56K 
CP/M $395/525 

□ PASCAL/MT- Subset of standard PASCAL, 
©Generates ROMable 8080 machine code. 
® Symbolic debugger Included. Supports inter- 
rupt procedures, CP/M file I/O and assembly 
language interface. Real variables can be BCD, 
software floating point, or AMD 9511 hardware 
floating point. Includes strings enumerations 



Sotlwar* / 
wild /Mi 

M.11U.I/ All 



* t 



and record data types. Manuafexplains BASIC- Vj 
PASCAL conversion. Requires 32K ,S250/S30\k 

□ APL/V80— Concise and powerful language for 
© application software development. Complex 

programming problems are reduced to simple 
expressionsTn APL. Features include up to 27K 
active workspace, shared variables, arrays of 
up to 8 dimensions, disk workspace and copy 
object library. The system also supports auxil- 
iary processors for interfacing I/O ports. Re- 
quires 48K CP/M and serial APL printing termi- 
nal or CRT $500/530 

LJALGOL-60— Powerful block-structured lan- 
©guage compiler featuring economical run-time 
dynamic allocation of memory. Very compact 
(24K total RAM) system implementing almost 
all Algol 60 report features plus many powerful 
extensions including string handling direct disk 
address I/O etc $199/520 

□ CBASIC-2 Disk Extended BASIC-Non- 
® interactive BASIC with pseudo-code compiler 

and run-time interpreter. Supports full file con- 
trol, chaining, integer and extended precision 
variables, etc. Versions of CRUN for CP/M ver- 
sions 1.4 and 2.x included on disk. . .$120/515 



• 



MICRO FOCUS 

] STANDARD CIS COBOL- ANSI 74 COBOL 
) standard compiler fully validated by U.S. Navy 
tesls to ANSI level 1 . Supports many features to 
level 2 including dynamic loading of COBOL 
modules and a full ISAM file facility. Also, pro- 
gram segmentation, interactive debug and 
powerful interactive extensions to support pro- 
tected and unprotected CRT screen formatting 
from COBOL programs used with any dumb 

terminal S850/S50 

] FORMS 2— CRT screen editor. Output is 
) COBOL data descriptions for copying into CIS 
COBOL programs. Automatically creates a 
query and update program of indexed files 
using CRT protected and unprotected screen 
formats. No programming experience needed. 
Output program directly compiled by STAN- 
DARD CIS COBOL 5200/S20 

J NEVADA COBOL- Subset of ANSI-74. Fea- 
tures fast compilation and execution with small 
object modules. Has extended arithmetic with 
18 digit accuracy. Extended I/O includes ran- 
dom access files and sequenlial files of both 
fixed and variable lenglh records, and interac- 
tive accept/display verbs. Good error mes- 
sages and debugging facilities enhance pro- 
gram development. Requires a 32K CP/M 
system S149/S25 

EIDOS SYSTEMS 

JKBASIC-Microsoft Disk Extended BASIC 
) version 4.51 integrated with KISS Multi-Keyed 
Index Sequenlial and Direct Access file man- 
agement as 9 additional BASIC commands. 
KTSS included as relocatable modules linkable 
to FORTRAN-80, COBOL-80. and BASIC 
COMPILER, Specify CP/M version 1.4 or 2.x 
when ordering. Requires 48K CP/M S585/S45 
To licensed users of Microsoft BASIC-80 
(MBASIC) S435/S45 

JXYBASIC Interactive Process Control 

BASIC— Full disk BASIC features plus unique 
commands to handle byte rotate and shift and 
to test and set bits. Available in several ver- 
sions: 

Integer ROM squared 5350/525 

Integer CP/M 5350/$25 

Extended ROM squared $450/$25 

Extended CP/M 5450/525 

Extended Disk CP/M -.5550/525 

Integer CP/M Run Time Compiler . .S350/525 
Extended CP/M Run Time CompilerS450/S25 

] RECLAIM— A utility to validate media under 
CP/M, Program tests a diskette or hard disk 
surface for errors, reserving the imperfections 

in Invisible files, and permitting conlinued 
usage of the remainder. Essential for any hard 
disk. Requires CP/M version 2 580/55 

j BASIC UTILITY DISK-Consists of: (1) 
OCRUNCH-14— Compacting utility to reduce 
the size and increase the speed of programs in 
Microsoft BASIC 4.51. BASIC-80 and TRS-80 
BASIC. (2) DPFUN- Double precision subrou- 
tines for computing nineteen transcendental 
functions including square root, natural log, log 
base 10. sine, arc sine, hyperbolic sine, hyper-. 
bolic arc sine, etc. Furnished in source on dis- 
kette and documentation 550/535 

] STRING/80— Character string handling plus 
routines for direct CP/M BOOS calls from 
FORTRAN and other compatible Microsoft lan- 
guages. The utility library contains routines that 
enable programs to chain to a COM file, retrieve 
command line parameters and search file direc- 
tories with full wild card facilities. Supplied as 
linkable modules In Microsofl format, $95/$20 

DSTRING/80 source code available 

separately— $295/NA 

JTHE STRING BIT- FORTRAN character 
I string handling. Routines to find, fill, pack, 
move, separate, concatenate and compare 
character strings. This package completely 
eliminates the problems associated with 
character string handling In FORTRAN. 

Supplied with source $65/515 

I VSORT— Versatile sort/merge system for fixed 
D length records with fixed or variable length 
fields. VSORT can be used as a stand-alone 
package or loaded and called as a subroutine 
from CBASIC-2. When used as a subroutine, 
VSORT maximizes the use of buffer space by 
saving the TPA on disk and restoring it on com- 
pletion of sorting. Records may be up to 255 
bytes long with a maximum of 5 fields. Upper/ 
lower case translation and numeric fields 

supported $175/520 

l IBM/CPM- Program to transfer IBM 3741 data 
set files to CP/MTlles or CP/M files to IBM 3741 
data sets. Easy to use. Requires two eight inch 
diskette drives, 24K memory, and a 24 by 80 
CRT terminal S175/S5 



CPAIds* 

] MASTER TAX — Professional tax preparation 
) program. Prepares schedules A, B, C, D, E, R 
' G, R/RP, SE, TC, ES and forms 2106. 2119, 
2210, 3468, 3903. 2441. 4625, 4726. 4797. 
4972. 5695 and 6251 . Printing can be on readily 
available, pre-printed continuous forms, on 
overlays, or on computer generated, IRS ap- 
proved forms. Maintains client history files and 
Is interactive with CPAids GENERAL LEDGER 

II (see below) 5995/S30 

Annual Update Fee $350 

j STANDARD TAX — As above for schedules A, 
B. C. D, E. G. R/RP, SE, TC and forms 2106 and 
2441, Also, does not maintain client history 

files $495/S30 

Annual Update Fee 5175 



Copyright © 1980 Lifeboat Associates. No por- 
tion ol this advertisement may be reproduced 
without prior permission. 



Neu In der Schwefz Lifeboat Associates GmbH, Aegeristr. 35, CH 6340 Baar Telefon 042/31 2931 



ttwara / 

with /Manual 
linuil/ Alone 



# 



. GENERAL LEDGER ll-Designed for CPAs. 

t Stores complete 12 monlh detailed history of 
transactions. Generates financial statements, 
depreciation, loan amortizations, journals, trial 
balances, statements of changes in financial 
position, and compilation letters. Includes 
payroll system with automatic posting to gen- 
eral ledger. Prints payroll register, W2's and 
payroll checks S450/S30 



Q T/MAKER — Powerful new tool for preparing 
management reports with tabular data. Makes 
financial modeling projects easy. Do you want a 
weekly profitability report? Set up the table and 
compute. Just change the sales figures for next 
week and compute. You have a new report! 
T/MAKER includes a full screen editor for 
setting up tables which pages left, right, up 
and down. Compute includes standard arith- 
metic, percents, exponents, common tran- 
scendental functions, averages, maxima, 
minima, projections, etc. Requires 48K CP/M, 
CBASIC-2. CRT terminal with addressable cur- 
sor positioning S275/S25 

UESQ-1 — Professional time and billing for the 
©legal profession. Designed for use by the first- 
t time computer user. Records billable and non- 
51 billable time. Complete system includes trans- 
nifi action entry, posting, billing, reports, and client 
analysis. Records cash receipts, escrow receipts, 
and escrow transfers. Requires 48K CP/M 
system, 480K of disk storage space, cursor ad- 
dressable CRT, and CBASJC-2 . . . .S1495/S50 
.'...Complete demonstration system for ESQ-1 

© S75/S50 

f 



tt-ar. . 
with /Ml 



Soltwaru / 

wlih / Manual 
Manual/ Alona 



y 






V 



C J BSTAM - Utility to link one computer to another 
® also equipped with BSTAM. Allows file transfers 
at full data speed (no conversion to hex), with 
CRC block control check for very reliable error 
detection and automatic retry. We use it! It's 
great! Full wildcard expansion to send *. COM, 
etc. 9600 baud with wire. 300 baud with phone 
connection. Both ends need one. Standard and 
® versions can talk to one another. This 
soltware requires a knowledge of assembler 
language for installation S150/S10 

□ BSTMS— Intelligent terminal program for 
®CP/M systems. Permits communication be- 
tween micros and mainframes. Sends charac- 
ter data files to remote computers under com- 
plete control. System can record character data 
sent from remote computer systems and data 
banks. Includes programs to EXPAND and 
COMPRESS binary files for transmission. This 
software requires a knowledge of assembler 
language for installation S200/S25 

ZDWHATSIT?*— Interactive data-base system 
using associative tags to retrieve information by 
subject. Hashing and random access used for 
fast response. Requires CBASIC-2 .S175/S25 -\X 

□ SELECTOR III-C2— Data Base Processor toV 
t create and maintain multi-key data bases. 

9 Prints formatted sorted reports with numerical 
summaries or mailing labels. Comes with sam- 
ple applications, including Sales Activity, Inven- 
tory, Payables, Receivables, Check Register, 
and Client/Patient Appointments, etc. Requires 
CBASIC-2. Supplied in source S295/S20 

□ GLECTOH— General Ledger option to 
SELECTOR III-C2. Interactive system provides 
for customized COA. Unique chart of transac- 
tion types insure proper double entry book- 
keeping. Generates balance sheets. P&L 
statements and journals. Two year record al- 
lows for statement of changes in financial posi- 
tion report. Supplied in source. Requires 
SELECTOR ll[-C2. CBASIC-2 and 56K 
system $350/$25 

MAGSAM III — Sophisticated keyed access file 
© support system. Supports random, sequential, 
and generic retrieval by key. Also, multiple sec- 
ondary keys. Dynamic allocation and extension 
of files with automatic free space reclamation. 
Interactive tutorial included to get the user 
started, Complete with documentation and 
quick reference card, Specify CBASIC or Mi- 
crosoft BASIC version. Requires 48K 
system S145/S25 

□ MAGSAM IV — High speed machine code ver- 
©sion of MAGSAM III for CBASIC only. Distrib- 
uted as pre-loaded modules and Microsofl re- 
locatable object modules S295/S2S 



G DATASTAR— Professional forms control entry 

© and display system for key-to-disk data cap- 
ture. Menu driven with built-in learning aids. 
Input field verification by length, mask, attribute 
(i.e. uppercase, lowercase, numeric, auto-dup, 
etc.). Built-in arithmetic capabilities using keyed 
data, constant and derived values. Visual feed- 
back for ease of forms design. Files compatible 
with CP/M-MP/M supported languages. Re- 
quires 32K CP/M and CRT with addressable 

cursor S350/S35 

DWORD-STAR— Menu driven visual word pro- 
© cessing system for use with standard terminals. 
Text formatting performed on screen. Facilities 
for text paginate, page number, justify, center 
and underscore. User can print one document 
while simultaneously editing a second. Edit 
facilities include global search and replace, 
Read/Write to other text files, block move. etc. 
Requires CRT terminal with addressable cursor 
positioning S445/S40 

DWORD-STAR-MAIL-MERGE-As above with 

©option for production mailing of personalized 

documents with mail lists from DATASTAR or 

NAD S575/S40 

DWORD-MASTER Text Editor- In one mode 
© has superset of CP/M's ED commands includ- 
ing global searching and replacing, forwards 
and backwards in file in video mode, provides 
full screen editor for users with serial address- 
able-cursor terminal S145/S25 

D MAGIC WAND*— Word processing system 
with simple, easy to use full screen text editor 
and powerful print processor. Editor has all 
standard editing functions including text insert 
and delete, global search and replace, block 
move and library files for boiler plate text. Print 
processor formatting commands include au- 
tomatic margins, pagination, headings & foot- 
ings, centered and justified text. Also prints with 
true proportional spacing, merges with data 
files for automatic form letters, and performs 
run-time conditional testing for varied output. 
Requires 32K CP/M and CRT terminal with ad- 
dressable cursor ■ . . .S395/S40 



D TEXTWRITER III- Text formatter to justify and 
® paginate letters and other documents. Special 
features include insertion of text during execu- 
tion from other disk files or console, permitting 
recipe documents to be created from linked 
fragments on other files. Has facilities for sorted 
index, table of contents and footnote insertions. 
Ideal for contracts, manuals, etc. Now compati- 
ble with Electric Pencil* and Word-Star pre- 
pared files S125/S20 

D DATEBOOK— Program to manage time just 
like an office appointment book but using the 
speed and memory ol a computer. Keeps track 
of three appointment schedules (three dental 
chairs, three attorneys, etc.) at once. Appoint- 
ments consist of name, reason for the appoint- 
ment, the date and time, and the length of the 
appointment. System can be quickly cus- 
tomized for the individual user. Many helpful 
features for making, changing, finding, and re- 
porting appointments. Requires 48K CP/M and 
180K bytes diskette storage, Requires 80 *24 
cursor addressable terminal. Specify 8080 

CP/M, Z80 CP/M or Cromemco CDOS 

5295/S25 



DMA 

□ CBS — Configurable Business System is a 
t comprehensive set of programs for defining 

custom data files and application systems with- 
out using a programming language such as 
BASIC, FORTRAN, etc. Multiple key fields for 
each data file are supported. Set-up program 
customizes system to user's CRT and printer. 
Provides fast and easy interactive data entry 
and retrieval with transaction processing. 
Report generator program does complex calcu- 
lations with stored and derived data, record 
selection with multiple criteria, and custom for- 
mats. Sample Inventory and mailing list sys- 
tems included No support language 
required S395/S40 

MICROPRO 

D SUPER-SORT I — Sort, merge, extract utility as 
© absolute executable program or linkable mod- 
ule in Microsoft format. Sorts fixed or variable 
records with data in binary. BCD. Packed Deci- 
mal. EBCDIC. ASCII, floating & fixed point, ex- 
ponential, field justified, etc. Even variable 
number of fields per record! S225/S25 

□ SUPER-SORT It-Above available as abso- 
© lute program only S175/S25 

□ SUPER-SORT III- As II without SELECT/ 
© EXCLUDE S125/S25 



PEACHTREE SOFTWARE* 

D General accounting software for small busi- 

© nesses. Each product can be used alone or with 

t automatic posting to the General Ledger, 

Supplied in source for Microsoft BASIC 4.51 . 

GENERAL LEDGER $530/$40 

ACCOUNTS PAYABLE S530/S40 

ACCOUNTS RECEIVABLE S530/S40 

PAYROLL $530/540 

INVENTORY S660/S40 

D Other application products supplied in source 
©for Microsoft BASIC 4.51. 

f MAILING ADDRESS S530/S40 

PROPERTY MANAGEMENT S925/S40 

GRAHAM. DORIAN SOFTWARE 
SYSTEMS 

□ Comprehensive accounting software written in 
©CBASIC-2 and supplied in source code. Each 
® software package can be used as a stand- 
f alone system or integrated with the General 
Ledger for automatic posting to ledger ac- 
counts. Requires CBASIC-2. 

GENERAL LEDGER $805/840 

ACCOUNTS PAYABLE $805/S40 

ACCOUNTS RECEIVABLE $805/840 

INVENTORY SYSTEM $555/$40 

JOB COSTING S805/S40 

APARTMENT MANAGEMENT . . . .5805/540 
CASH REGISTER $805/S40 

D POSTMASTER— A comprehensive package 
®for mail list maintenance that is completely 
menu' driven. Features include keyed record 
extraction and label production. A form letter 
program is included which provides neat letters 
on single sheet or continuous forms. Includes 
NAD file translator. Requires CBASIC-2. 
$150/520 



STRUCTURED SYSTEMS GROUP 

□ Complete interactive accounting software for 
t business. Each product can be used stand- 
alone or with automatic posting to the general 

ledger. Each product is thoroughly tested and 
very well documented. 

GENERAL LEDGER $820/540 

ACCOUNTS RECEIVABLE SB20/540 

ACCOUNTS PAYABLE $820/540 

PAYROLL $820/540 

INVENTORY CONTROL S820/S40 



I ] ANALYST— Customized data entry and report- C 

t ing system. User specifies up to 75 data items 
per record. Interactive data entry, retrieval, r- 
and update facility makes information 
managemenl easy. Sophisticated report 
generator provides customized reports using 
selected records with multiple level break- C 
points for summarization. Requires a disk sort 
utility such as QSORT. SUPER-SORT or 
VSORT and CBASIC-2 $250/515 

I iLETTERIGHT— Program to create, edit and 
type letters or other documents. Has facilities to 
enter, display, delete and move text, with good 
video screen presentation. Integrates with NAD j^j 
for form letter mailinqs $200/$25fl* w 

I I NAD— Name and Address selection system. ™ 
Interactive mail list creation and maintenance 
program with output as full reports with refer- D 
ence data or restricted information for mail 
labels. Transfer system for extraction and trans- 
fer of selected records to create new files. 
OSORT required if sorting is desired. $100/$20 □ 

[} QSORT— Fast sort/merge program for files 
with fixed record length, variable field length 
information. Up to five ascending or descend- 
ing keys. Full back-up of input files created n 
$100/520 

• •••••* 

nHEAD CLEANING DISKETTE-Cleans the 
drive Read/Write head in 30 seconds. Diskette D 
absorbs loose oxide particles, fingerprints, and 
other foreign particles that might hinder the per- 
formance of the drive head. Lasts at least 3 q 
months with daily use. Specify 5' or 8". 

Single sided $20 each/$55 for 3 

Double sided $25 each/565 for 3 LJ 



NEWSLETTER 
FROM LIFEBOAT 

LIFELINES is the first step in software support for the 
serious microcomputer user. Each issue reports 
new revisions together with information on the purpose 
tor each such release, be it for correction of "bugs" 
or the addition of features and facilities. 
Feature Articles I New Software I Product 
Comparisons I Info on CP/M Users Group I 

SUBSCRIPTION INFORMATION: 

$1 8 for twelve issues: U.S., Canada, and Mexico. 

$40 for twelve issues; all other countries. 

$2.50 for each back issue: U.S., Canada, and 

Mexico. 

$3.60 for each back issue: all other countries. 

Send Check to LIFELINES, 1 651 Third Avenue, 
New York, N.Y 1 0028 or use your VISA or 
MASTERCARD-call (212) 722-1700 



DC 300 Data Cartridges Specify 450'XL or 

300' certified. Pack of 5 5100 

FLIPPY DISK KIT- Template and instructions 
to modify single sided 5Va" diskettes for use of 

second side in single sided drives $12.50 

FLOPPY SAVER— Protection for center holes 
for 5" and 8" floppy disks. Only 1 needed per 
diskette. Kit contains centering post, pressure 
tool and tough 7 mil mylar reinforcing rings for 
25 diskettes. 

5, Kit $14.95 

5", Rings only $7.95 

8". Kit $16.95 

', Rings only SB. 95 

The CP/M HANDBOOK (with MP/M) by Rod- 
nay Zaks $13.95 

PASCAL USER MANUAL AND REPORT-By 

Jensen and Wirth. The standard textbook on 
the language. Recommended for use by 
Pascal/Z, Pascal/M and Pascal/MT users $12 

THE C PROGRAMMING LANGUAGE- By 

Kernighan and Ritchie. The standard textbook 
on the language. Recommended for use by 
BDS C, tiny C. and Whitesmiths C users . .$12 

STRUCTURED MICROPROCESSOR PRO- 
GRAMMING- By the authors of SMAL/80. 
Covers structured programming, the 8080/ 
8085 instruction set and the SMAL/80 lan- 
guage $20 

ACCOUNTS PAYABLE & ACCOUNTS 

RECEIVABLE- CBASIC book by Osborne/ 

McGraw-Hill $20 

GENERAL LEDGER - CBASIC book by 

Osborne/McGraw-Hill $20 

PAYROLL WITH COST ACCOUNTING- 
CBASIC book by Osborne/McGraw-Hill . .$20 

• **•••** 

* Program names trademarked 

f Recommended system configuration consists 
of 48K CP/M, 2 full size disk drives, 24 x 80 CRT 
and 132 column printer. 

® Modified version available for use with CP/M as 
implemented on Heath and TRS-80 Model I 
computers. 

©User license agreement for this product must 
be signed and returned to Lifeboat Associates 
before shipment may be made. 

©This product Includes/eXcludes the language 
©manual recommended in Condiments. 

©Serial number of CP/M system must be 
supplied with orders. 



©Requires Z80 CPU. 



**•*•*** 



Ordering Information 



MEDIA FORMAT ORDERING CODES. 
When ordering, please specify format code. 



LIFEBOAT ASSOCIATES MEDIA FORMATS LIST. Diskette, cartridge disk and cartridge tape 
format codes to be specified when ordering software for listed computer or disk systems. All 
software products have specific requirements in terms of hardware or software support, such as 
MPU type, memory size, support operating system or language. 



Computer lyiiim Format Coda 

Alialr BSOODiSk . . . See MITS 3200 

Alios AT 

Apple - ScftCard 13 Sector , , . ,RG 
Apple + SoftCard 1 6 Seclor . , . .RR 

AVL Eagle RB 

BASF Syslem 7100 RD 

Blackhawk Single Density 03 

Blackhawk Micropenis Mod II 03 

CDS Versatile 3B Ql 

CDS Versatile 4 Q2 

COMPAL-80 Q2 

Cromemco System 3 Ar 

Cromemco Z2D R6 

CSSN BACKUP (lape) T1# 

Delia AT 

Dlgl-Log Mlcroterm II RD 

Digital Microsystems Ar 

Discus See Morrow Discus 

Ourango F-85 RL 

Dyiabyte DBB/2 R1 

Dynabyte DB8/4 A1* 

Exldy Sorcerer h Lifeboat CP/M .02 
Exidy Sorcerer - Exldy CP/M , . .04 

Heath HB - H17/H27 P4 

Heath H89 - Lifeboat CP/M . . . .P4 
Haalh HB9 - Magnolia CP/M . . .P7 
Hallos II ,See Processor Technology 

Horizon See Norlh Star 

ICOM 2411 Microfloppy R3 

iCOM 3712 A1 

ICOM 3B12 AT 

Prices reflect distribution on 8' 
single density diskettes. If a 
format is requested which 
requires additional diskettes, a 
surcharge of SB. per additional 
diskette will be added. 
Prices FO.B. New York, 
Shipping, handling and C.O.D. 
charges extra, 

Manual cost applicable against 
price of subsequent software 
purchase. 

The sale of each proprietary 
software package conveys a 
license for use on one 
3m only. 




Computer ayaiem For mat Cod a 

ICOM 4511 5440 Cartridge 

CP/M 1.4 D1# 

ICOM 4511 5440 Cartridge 

CP/M 2.2 D2# 

IMS 5000 RA 

IMS 8000 AT 

IMSAI VDP-40 R4" 

IMSAI VDP-42 R4" 

IMSAI VDP-44 R5" 

IMSAI VDP-60 AT" 

Intecolor See ISC Intecolor 

Intel MDS Single Density A2 

Intel MDS Double Density A5 

Interlec SuperBraln DOS 0.1 ... R7 
Inlertec SuperBraln DOS 0.5-2. X RJ 

Inlertec SuperBraln DOS 3.X RK 

ISC Intecolor 6063/8360/B963 . ,A1 

Konlron PSI-80 RF 

Meca5'/<" P6 

Mlcromallon 

(Except TRS-80 below) AT 

MicropoliS Mod I Ql 

Micropolls Mod II 02 

MITS 3200/3202 B1 

Morrow Discus AT 

Mostek A1 

MSD5WT RC 

North Star Single Density P1 

North Star Double/Quad P2 

Nylac Single Density 03 

NylacMlcropollsMod.il 02 

Oh'o Scientific C3 A3 

OnyxCSOOl T2# 

Pertec PCC 2000 AT 

Processor Technology Helios II . .B2 

Quay 500 RO 

Quay 520 RP 

RAIR Single Density R9 

• Single-Side Single-Density disks 
are supplied for use with Double- 
Density and Double-Side 8 soft 
seclor format systems. 

" IMSAI formats are single density 
with directory offset of zero. 

# A media surcharge ol 525 (or or- 
ders on tape formats Tl and T2 and 
ol S100 for orders on disk lormats 
D1 and D2 will be added. 

The list of available formats Is sub- 
ject to change withoul notice. In 
case of uncertainty, call to confirm 
the lormat code lor any particular 
equipment. 



Computer ayitem Formal CoOa 

RAIR Double Density RE 

Research Machines 8 A1 

Research Machines 5Vi" RH 

REX 03 

Sanco7000 5'/i" RQ 

SD Systems 8' AT 

SO Systems 5'/*" R3 

Sorcerer See Exidy Sorcerer 

Spacebyle Ai 

SuperBraln See Interlec 

Tarbell AT 

Tfittt" R3 

TEI 8 AT 

Thlnkertoys See Morrow Discus 

TRS-80 Model I 5 'A" R2 

TRS-80 Model I - FEC Freedom RN 
TRS-80 Model I - Mlcromallon . .A4" 
TRS-80 Model I -r Omlkron 5V*" .RM 
TRS-80 Model I 4 Omlkron 8" . . .A1 
TRS-80 Model I - ShuflleboardB" A1 

TRS-80 Model II AT 

VDP-40/42/44/80 See IMSAI 

Vector Graphic Q2 

Vector MZ Q2 

Versatile See CDS Versatile 

Vista V8D 5V* Single Density . . . .P5 
Vista V200 BVSt* DoublB Density . ,P6 
Zenith Z69 • Lifeboat CP/M ...,P4 
Zenith ZB9 - Magnolia CP/M . . .P7 




Lifeboat ASSOCiateS, 1651 Third Avenue, N.Y, N.Y 10028 (212)860-0300 ™The Software Supermarket is a trademark 

International Telex: 220501 , Domestic Telex: 640693 of L,feboat Assoc,ates 



<aa* For The 

$ 99 GENERAL 







The Micro Computer General 85 



OEM Industry 
University 



FOR USE IN: 

° Laboratory 
Home 



The General is a 4.5" x 6" single board micro 
computer, ideal for industrial control applications 
as well as for dedicated test monitoring systems, 
communication subsystems, small scale data 
processing and front end processing. Through its 
advanced design, it is adaptable for data logging, 
data acquisition, prototyping and experimenting. 

Program development is facilitated through the 
General's "Expeditor" system monitor. The Ex- 
peditor has specialized commands for automatic 
baud rate selection — uploading and download- 
ing which speed up development and cut down on 
"hidden" program costs. An optional assembler 
and disassembler on a 2716 will compliment the 
Expeditor and will further reduce programming 
time and cost. 

The General comes complete with the Deluxe 
Users Manual which offers complete instructions 
on hardware and software usage. 

THE GENERAL — ONE POWERFUL 
COMPUTER SYSTEM 



HARDWARE FEATURES 

Board dimensions — 4.5" x 6" 

8085 A CPU 

4 Level programmable Interrupt 

3 Priority Interrupts 

2 Non-maskable Interrupts 

256 Bytes of programmable memory 

(expandable on board to 2 K bytes of 

either Static Ram or CMOS Ram with 

battery back-up) 

2 K Bytes of EPROM — expandable 

on board to 4 K bytes 

22 Programmable parallel I/O lines 

(ports) 

6 Bit memory mapped port 

Programmable 14 bit binary counter 

and timer controlled through the 

system software 

Software compatible with the 8080 

THE GENERAL MCG-85 $99.00 

(Kit) 

The GENERAL MCG-85 $135.00 

(Assembled & Tested) 

2 K Expansion Rom 



SOFTWARE FEATURES 

EXPEDITOR — 2 K SYSTEM MONITOR 

Automatic Baud Rate 
Selection (50-9600 Baud) 

° Downloading — from a computer that 
supports an assembler. This will enable 
the user to develop programs on a time 
sharing service, a larger computer, and 
download directly to the Ram of the 
General. 

° Uploading — Develop programs on the 
General and upload them to a computer 
that supports a disk drive for program 
storage. 



Hex Keypad and Display $69.00 
2 K Basic in Rom $59.00 



$30.00 



2 K Assembler & 

Disassembler $40.00 

2 K Expansion Ram $30.00 Expeditor Monitor Listings $29.00 

(Manual Form) 
2 weeks to clear) or charge to Visa or Master 
add 8% sales tax. 



Send certified check (regular checks require 
Card. Add $3.00 shipping. N.Y. residents 



L 



* In Kit form, single quantity, introductory offer. 
Dealer Inquiries Invited 

ATLANTIS COMPUTERS 

Division of 
Atlantis Computerized Services 

34-13 30 Ave. Astoria, NY 11103 
(212) 728-6700 



Desk-Top Wonders 



Self-Modifying Code 
for the TI-58/59 

Ted Green, Box 2289- AMR 

Johns Hopkins University 

Charles and 34th St 

Baltimore MD 21218 

Because of the four multiregister memories in the Texas 
Instruments TI-59 programmable calculator and their 
ability to hold either data or program steps, it is possible 
to let the TI-59 change its set of instructions, or any seg- 
ment of its instructions, at any time during the program. 
This is done by "overlapping" data registers and program 
steps. 

To see how the TI-59 stores numbers contained in the 
data register in the program-step memory, enter the 
following, repartitioning to 100 data memories, steps: 

1234567891 
ST0 99 


Op 17 
GTO 000 
LRN 

Examine the LRN mode using SST; keep in mind that 
originally there was nothing in the LRN mode. Now, we 
examine the following locations: 

000 90 

001 00 

002 00 

003 91 

004 78 

005 56 

006 34 

007 12 

The code in location 000 represents the type of number 
that was entered. In this case, the 9 stands for a number 
that consumed 9 memory locations (location 007 repre- 
sents memory location 1, location 6 represents memory 
locations 2 and 3, location 5 is for memory locations 4 
and 5, etc). Notice that the number entered as 
1234567891 is stored as 9178563412 (starting at location 
003). The empty registers 001 and 002 are used for the 
storage of up to thirteen digits (in location 001, the 
rightmost digit is always 0). If you entered 1234567891 
and stored it in data register 98, your LRN mode would 
look like this: 



000 00 


008 90 


001 00 


009 00 


002 00 


010 00 


003 00 


011 91 


004 00 


012 78 


005 00 


013 56 


006 00 


014 34 


007 00 


015 12 



142 January 1981 © BYTE Publications lnc 



Circle 90 on inquiry card. 



Circle 91 on inquiry card. 



New on the North Star Horizon: 

18Mb Hard Disk Drive! 




r i 


o 

I I 


L 


.^fl 



Horizon Computer with 64K RAM 
and dual quad capacity (720kb) 
floppy disks 



Up to four 18Mb Winchester- 
type hard disk drives 



Display terminal 



Letter-quality or dot 
matrix printer 



Horizon I/O flexibility 
allows expansion to 
meet your needs 



Unsurpassed Performance and Capacity! 

North Star now gives you hard disk capacity and process- 
ing performance never before possible at such a low 
price! Horizon is a proven, reliable, affordable computer 
system with unique hardware and software. Now the 
Horizon's capabilities are expanded to meet your growing 
system requirements. In addition to hard disk perform- 
ance, the Horizon has I/O versatility and an optional hard- 
ware floating point board for high-performance number 
crunching. The North Star large disk is a Century Data 
Marksman, a Winchester-type drive that holds 18 million 
bytes of formatted data. The North Star controller inter- 
faces the drive(s) to the Horizon and takes full advantage 



NorthStaf^ 

North Star Computers, Inc. 

1440 Fourth St. 

Berkeley, CA 94710 

(415) 527-6950 TWX/Telex 910-366-7001 



of the high-performance characteristics of the drive. Our 
hard disk operating system implements a powerful file 
system as well as backup and recovery on floppy diskette. 

Software Is The Key! 

The Horizon's success to date has been built on the qual- 
ity of its system software (BASIC, DOS, PASCAL) and 
the very broad range and availability of application soft- 
ware. This reputation continues with our new hard disk 
system. Existing software is upward compatible for use 
with the hard disk system. And, with the dramatic increase 
in on-line storage and speed, there will be a continually 
expanding library of readily available application software. 
For more information, see your North Star dealer! 



HORIZON-HD-18 

Horizon computer with 64K 
RAM, 2 quad capacity mini 
drives and one HDS-18 hard 
disk drive $9329 

HDS-18 

Additional 18Mb hard disk drive 
for expansion of Horizon HD-18, 
or your present Horizon $4999 



SYS-1N 

Complete Horizon HD-18 plus 
80 x 24 display terminal and 
NEC Spinwriter printer $13,239 



SYS-1A 

Complete Horizon HD-18 with 
80 x 24 display terminal and 
Anadex printer $11,319 



Desk- Top Wonders. 



Storing the same number in data register 97 would use 
memory locations 016 thru 023, and so on. This scheme 
continues throughout, with data register 00 taking up 
memory locations 952 thru 959. 

To apply this principle, try the following example: 

9 

Op 17 

8166950185 

+ 
.686 

ST0 99 

Op 17 

RST 

Now examine the LRN mode and notice the following: 

000 90 List 

001 60 Deg 

002 68 Nop 

003 85 + 

004 01 1 

005 95 = 

006 66 Pause 

007 81 RST 

This is a counting program. Press RST, R/S, 1 . . . 2 . . . 
3 . . . 4 . . . etc. The .686 was added because neither the 
Deg nor the Nop have any effect on numbers that are 
"carried" from one step to another. 

There are drawbacks to this storage system. For in- 
stance, if the number 1 is stored in memory 99, all pro- 
gram locations 001 thru 006 are cleared, erasing every- 
thing between 000 and 007. Also, the instruction 000 90 
appears to be troublesome and cannot be changed to a 
useful code; all it does is take up space. In addition, the 
code in 002 always has a on the rightmost side, which 
disables the code. Keep in mind that this also applies to 
codes 008 and 009, 017 and 018, all the way up through 
952 and 953. 

Listing 1 is an actual program that will first begin as a 
counting program, then, after adding 1, it will modify its 
instructions so that it becomes a subtraction program. ■ 



Listing 1: A demonstration program showing self-modifying 
code on the Texas Instruments TI-58 or Tl-59 programmable 
calculators. When run, the program adds 1 to the number on the 
display, then continually subtracts until R/S is pressed. Begin 
execution at step 950. As soon as the program begins, hold 
down the Pause key to see the program work. After the pro- 
gram has been run, examine the LRN mode to observe how the 
code has been modified. 



Step 



Code 



Key 



000 


76 


Lbl 


001 


12 


B 


002 


05 


5 


003 


69 


Op 


004 


17 


17 


005 


01 


1 


006 


01 


1 


007 


06 


6 


008 


01 


1 


009 


09 


9 


010 


05 


5 


011 


00 





012 


01 


1 


013 


07 


7 


014 


05 


5 


015 


85 


+ 


016 


93 




017 


06 


6 


018 


08 


8 


019 


06 


6 


020 


95 


= 


021 


42 


STO 


022 


00 


00 


023 


00 


00 


024 


69 


Op 


025 


17 


17 


026 


61 


GTO 


027 


09 


949 


028 


49 


— 


949 


32 


xgt 


950 


76 


Lbl 


951 


11 


A 


952 


85 


+ 


953 


01 


1 


954 


95 


= 


955 


32 


xgt 


956 


61 


GTO 


957 


12 


B 



* NORTH STAR USERS * 

8" FLOPPY SUBSYSTEM HAS DAWNED ON THE HORIZO 



COMPLETE WITH MANUALS. SOFTWARE, HARDWARE FULLY INTEGRATED, READY TO RUN 

v Totally compatible with North Star hardware * Allows use of 8' and/or 5" drives * Detailed, 80 page manual included * Background print tasks 
* Supports Hoppy files up to 4.2 MB * Simple, plug-in operation * Fully CP/M" compatible *File security * Extensive utilities included 



DMA-DOS Software S200 

Dynamic Microprocess Associates Disk Operating System 

Tarbell Double Density Controller $420 

Cables $40 



Dual Shugart 8" 800R drives in cabinet with fan 

and power supply $1,250 

Total package $1,910 

Prices antl offers subject to change without notice 



n WE WILL PAY SHIPPING ON PREPAID ORDERS (Continental USA only). WE HAVE NO READER INQUIRY NUMBER. PLEASE WRITE OR CALL. 



JOHN D. OWENS ASSOCIATES, INC. 

12 SCHUBERT STREET, STATEN ISLAND, NEW YORK 10305 
OVERSEAS CALLERS: TWX 710 588 2844 or call (212) 448 6298*DOMESTIC CALLS: (212) 448 6283 (212) 448 6298 (212) 448 2913 



144 January 1981 © BYTE Publications Inc 




baZic is written entirely in Z80 5 code — baZic runs as much 
as 30% faster than North Star 8 BASIC. The greater execu- 
tion speed is significandy advantageous for hea\y number 
crunching, multiuser and multitasking operations. 

baZic has all the features of North Star BASIC — and 
then some.baZic, with minor exceptions, is 100% compatible 
with existing North Star BASIC programs. Our new baZic 
s under all Micro Mike's timesharing and hard disk 
rating software, including JOEDOS/.IOESHARE/ 
SHARE and 5SHARE. 

CHECK THESE FEATURES AT YOUR 
COMPUTER DEALER: 

■ lakes full advantage of the Z80 instruction set 

■ Can be used on any Z80-based microcomputer operating 
under North Star DOS or CP/M* (CP/M versions available 
early '81) 

■ Supports North Star floating point board for even faster 
execution of compute intensive programs 



■ Makes Multiuser systems with floppy disks more practical 

■ Improves performance of Multiuser Hard Disk systems 

■ baZic adds functions to assist in screen formatting, as well as 
features to simplify programming, e.g. APPEND command/ 
statement, ON GOSUB, cursor-addressable PRINT, etc. 

■ baZic, as shipped, includes 8, 10, 12 and 14 digit precisions, 
including both software and hardware floating point versions 

■ baZic is now included with Micro Mike's operating system 
software and applications programs 

Dealers and OEM's: Special Discounts Available 

For complete information, contact your North Star dealer or 
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"North Star Computers, Inc. 

"Zilog, Inc. 

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Micro Mike's Inc. 

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Circle 92 on inquiry card. 



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146 BYTE January 1981 



Circle 93 on inquiry card. 




1 I 



under one roof! 



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Circle 94 on inquiry card. 



Generating Bar Code 
in the Hewlett-Packard Format 



The HP-41C is Hewlett-Packard's 
newest entry in the hand-held pro- 
grammable calculator race. The main 
feature that distinguishes it from 
Hewlett-Packard's earlier calculators 
is its modular design, which allows 
the HP-41C to be extended by a line 
of peripheral devices. Up to four 
peripherals can be plugged into the 
calculator, and these include a 
magnetic card reader, a thermal 
printer, memory modules to increase 
the amount of memory available to 
the user, and "application pacs" that 
contain software for particular ap- 
plications in read-only-memory 
module form. In addition, Hewlett- 
Packard has introduced the 82153A 
Optical Reader (also called a Wand), 
which is capable of reading bar codes 
that contain HP-41C programs, data, 
or function definitions. 

This article describes the HP-41C 
bar-code format and includes a 
BASIC program that converts an HP- 
41C program into a series of bar-code 
rows that can be printed using a high- 
quality printer with incremental spac- 
ing. 

HP-41C Bar-Code Format 

The bar code that is read by the 
Wand is simply binary information 
represented by wide and narrow bars 
(representing 1 and 0, respectively). 
The space- 'between each bar is 
nominally the width of the narrow 
bar and serves as a benchmark for the 
current unit bar width. The unit bar 
width must be greater than 15 mils. A 
narrow bar may be up to 20% wider 
than the unit bar width, which is 



Thomas McNeal 

Hewlett-Packard 

Cupertino Integrated Circuits Operation 

10900 Wolfe Rd 

Cupertino CA 95014 

established by the previous bar and 
space. A wide bar should be twice the 
unit bar width, and a wide bar should 
vary no more than 20% from its stan- 
dard value. 

The bars are logically grouped into 
8-bit bytes, and a bar-code program 
is organized into rows of a maximum 
of 16 bytes, with 3 bytes of header 
information and up to 13 bytes of 
data per row. Associated with each 
row are pairs of start and stop bits 
(binary 00 and 10, respectively) that 
allow the rows to be read in either 
direction. Figure 1 shows the format 
for a single row of program bar code. 

The 13 data bytes contain the ma- 
chine language of the HP-41C instruc- 
tion set. Table 1 lists these instruc- 
tions, with the first 8-bit byte of each 
instruction determining the instruc- 
tion type. Additional bytes, if any, 
contain alphanumeric character data, 
numeric or stack operands, or linkage 
information. 

All indirect instructions are 2 bytes 
long, with the high-order bit of the 
second byte set to 1 to signify an in- 
direct operand. In the case of indirect 
numeric GOTO and EXECUTE in- 
structions, the high-order bit is set to 
1 for an EXECUTE instruction and 
cleared to for a GOTO instruction. 

The size of an instruction is deter- 
mined by its position in the table. In 
order to save room in the HP-41C, 
some instructions may have two com- 
pletely different representations, de- 
pending on the value of the operand 
associated with that instruction. For 
example, the numeric label instruc- 
tion is represented by 1 byte if the 



operand is less than 15 and, other- 
wise, by 2 bytes. The XROM (EXE- 
CUTE read-only -memory module) in- 
structions seen in the function table 
also save room when a reference to an 
alpha label within a read-only-mem- 
ory module is made by an EXECUTE 
instruction. The XROM instruction is 
a compact, 2-byte reference to a table 
of alphanumeric labels within the 
read-only-memory module; this re- 
places the EXECUTE instruction orig- 
inally entered by the user. 

HP-41C Internal Representation 

The instructions generally are 1, 2, 
or 3 bytes long, with the 4 high-order 
bits of the first byte indicating the in- 
struction length. The exceptions to 
this rule are the instructions contain- 
ing alphanumeric character data. The 
HP-41C has an alphanumeric display 
that allows the definition of instruc- 
tions with nonnumeric operands. 
These functions include an alpha- 
numeric label instruction, which con- 
tains a label of up to seven characters, 
GOTO and EXECUTE instructions 
with alphanumeric label operands, 
and a text-entry instruction. This last 
instruction will either append or re- 
place character data in a special 
alphanumeric register and may con- 
tain up to fifteen characters. 

All character data is represented in 
ASCII (American Standard Code for 
Information Interchange), with one 
character per byte and a few excep- 
tions for special characters not found 
in the ASCII character set. Since 
character-oriented instructions are of 
indeterminate length, their size is 



148 January 1981 © BYTE Publications Inc 




Please send your free software catalog. 

(Check which software is of particular interest) 

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8085, 8080. Full C language as defined in Kernighan and Ritchie, with com- 
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□ PASCAL COMPILER. Optimized native code for VAX 11/780, PDP-11, 
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City 



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Idris is a trademark of Whitesmiths Ltd. 
UNIX is a trademark of Bell Laboratories. 
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VMS. RSX-11. RT-11, RSTS/E. VAX, 
PDP-11. LSI-11 are trademarks of Digital 
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Whitesmiths, Ltd. 

Software for grownups. 

(212)799-1200 ° r 

RO.B. 1132 Ansonia Station, New York, N.Y. 10023 



VALUE 



FUNCTION 



NUMBER 
OF BITS 



nnnnnnnn 



nnnn 



(UP TO 13 BYTES )- 



• I nnnn 
J 



10 



START 
BITS 



CHECKSUM 



SEQUENCE 
NUMBER 



LEADING 
PARTIAL 
FCN BYTES 



DATA 



(TRAILING 
I PARTIAL 
I FCN BYTES 



STOP 
BITS 



UP TO 104 



Figure 1: Format for Hewlett-Packard bar codes. A maximum of 13 bytes can be encoded into one row of bar code. 



embedded within a word in the in- 
struction itself. For alphanumeric 
label operands, the number of char- 
acters is held in the 4 low-order bits of 
the second or third byte, with the 4 
high-order bits set to hexadecimal F. 



The position of this byte is indicated 
in the documentation of the compile 
routine of the bar-code generating 
program. (See listing 1.) This conven- 
tion allows differentiation between an 
alphanumeric label instruction and an 



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end instruction, in which the third 
word contains a hexadecimal F in the 
low rather than the high 4 bits. 

In addition, the alphanumeric label 
and end instructions contain pointers 
that link them with other alpha- 
numeric label and end instructions, 
creating an alphanumeric label chain. 
This chain is used to identify the posi- 
tion of labels and program bound- 
aries within the HP-41C program 
memory and establishes entry points 
for each program. The chain is re- 
compiled by the Wand software, so 
the bytes containing the chain point- 
ers are set to by this program. 

For a detailed discussion of the 
function table and other internal fea- 
tures of the HP-41C, refer to a series 
of articles that appeared in the Cor- 
vallis Division Column of the PCC 
Journal beginning on September 6, 
1979. The PPC Journal is a publica- 
tion of the PPC (Personal Program- 
mable Calculator), an independent 
user group for Hewlett-Packard pro- 
grammable calculators. Further infor- 
mation may be obtained by writing 
to: 

Richard Nelson, Editor 
PPC Journal 
2541 W Camden PI 
Santa Ana CA 92704 

The header information necessary 
for a bar-code program is contained 
in the left-most 3 bytes of each bar 
code row. The first byte is a parity 
check in the form of a running check- 
sum (a summation modulo 256, with 
wrap-around carry, of the checksum 
of the preceding row and all other 
bytes of the current row). 

The second byte is split into two 
parts. The 4 high-order bits contain 
the program type (l=nonprivate, 
2 = private), and the 4 low-order bits 
contain the sequence number, which 
is the bar-code row number minus 1, 
modulo 16. The sequence number 
will be inspected by the Wand soft- 
ware to assure that the correct row is 
being read. 

Text continued on page 172 
Circle 96 on inquiry card. — j 



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LOW ORDER 4 BITS 













1 


2 


3 4 


5 


6 7 




o 


NULL 


LBLOO 


LBL01 


LBL 02 LBL 03 


LBL 04 


LBL 05 LBL06~> 




_ 


digit 



1 


2 


3 4 


5 


6 7 




CM 


RCLOO 


RCL 01 


RCL 02 


RCL 03 RCL 04 


RCL 05 


RCL 06 RCL 07 






STO00 
+ 


STO01 


STO 02 

* 


STO 03 STO 04 
/ X<Y? 


STO 05 
X>Y? 


STO 06 STO 07 
X<=Y? £ + 


' BYTE 


1 4 BITS 
6 5 


LN 


X 2 


SORT 


Y* CHS 


e* 


LOG 10* 




1/X 


ABS 


FACT 


X*0? X>0? 


LN(1 +X) 


X<0? X = 0? 




LU 


CL 


XoY 


PI 


CLST Rt 


RDN 


LASTX CLX 




O 
T °° 


DEG 


RAD 


GRAD 


ENTERt STOP 


RTN 


BEEP CLA .> 




CD 
x » 


RCL nn 


STO nn 


ST+ nn 


ST- nn ST* nn 


ST/nn 


ISG nn DSE nn~ 


L 


< 

m 


XROM 


XROM 
GTO 00 


XROM 
GTO 01 


XROM XROM 
GTO 02 GTO 03 


XROM 
GTO 04 


XROM XROM 
GTO 05 GTO 06 


t 2 

/ BYTES 












.-> 




o 

Q 


-^ 






QTO nn 




r -) 


3 






I 


LU 


-^ 










- / 


BYTES 






J 


LU. 




TEXT 

1 


TEXT 
2 


TEXT TEXT 
3 4 


TEXT 
5 


TEXT TEXT "\ 
6 7 J 


UP 

TO 16 
BYTES 


Table 1: /I fnb/e /or the HP-41C instruction set. 


Instructions in the HP-41C are 


stored as one 


or more 8-bit bytes. 
















Table 1 continued or 


page 154. 



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Present cassette users may 
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See your dealer or order direct. For v^ 
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152 January 1981 © BYTE Publications Inc 



Circle 97 on inquiry card. 



Free software ($50-$120 worth) 
when you buy aTI programmable. 



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MODULE 1 PAKETTE 1: 

MODULE 2: PAKETTE 2: 




"b! 



Name 



Address 



Cily 



State 



Zip 



ALTERNATE MODULE: 

Send to: Texas Instruments Free Software Offer 

P.O. Box 725, Dept. M, Lubbock, Texas 79491 Calculator Serial Number (from back of unit) 

Return this coupon with (1) Customer Information Card (packed with calculator). (2) Dated copy ol prool of purchase between 
January 15, 1981-March 31. 1981 Items must be postmarked by April 14. 1981. Please allow 30 days lor delivery Otter void where 
prohibited Otter good only in U.S.A. TI reserves the right to substitute items 



U.S. sug^esterl retail prices. *For use with TI-59 only. 



Texas Instruments 



) 1981 Texas Instruments Incorporated 



NCORPOR ATED 



J 



45746 



Circle 98 on Inquiry card. 



Table 1 continued 






LOW-ORDER 4 BITS 












8 


9 


A 


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BYTES 



Quiet Designs 



Preformatted Disks: 

Compatible with Lanier 'No Problem', 
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A.M. 425, C.P.T. 6000/8000, Canon 

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For all systems using unformatted disks 

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Quiet Designs Inc. 
1330 W. Robinhood Dr., 
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473 Macara #706 
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Ph. (604) 273-9710 



154 January 1981 © BYTE Publications Inc 



Circle 99 on inquiry card. 



^a 




BASIC SOFTWARE LIBRARY 

NOW * 10 * Volumes and Growing 

WHY Pay hundreds of dollars for Software that does Not work when WE offer the BEST 
available Software for only a few dollars a program. And what is better OURS WORKS! 

We have over 100,000 in circulation since 1975 and we are still around and That's more than Anyone else can say. We 
used to sell hundreds of programs individually, the programs in Volume X were sold for several years at over $10,000, 
in Volume III for over $6,000 but a few years ago we decided to promote software to the mass public and it was an 
instant success. 

For Homeowners, Businessmen, Engineers, Hobbyists, Doctors, Lawyers, Men and Women 



Vol. 1 $24.95 


Vol. II $24.95 


Business & 


Animals Four 


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Astronaut 


Chi-Sq. 


Conv. 


Bookkeeping 


Bagel 


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Filter 


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Bio Cycle 


Confidence 1 


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Integration 1 


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Correlations 


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Building 


Craps 


Curve 


Intensity 


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Bingo 

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Bull 

Enterprise 

Football 

Funds 1 

Funds 2 

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Lite 

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Vol. VIII ■ 
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APPENDIX C 
Favorites 



Vol. IX 
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by December 31st, 1980 

Jnconditional Money Back Guarantee. 



Almost every single program 
included in these volumes will run in 
every Computer system that 
operates in Basic. A few changes 
may be required for some Basics but 
most of these changes are covered in 
one of the Tables and Appendices 
included in Volumes III, V, VI, 
VIM, and X. 

Volume VI — Disk programs are 
compatible with TRS-80 disk basic 

The disk programs in Volumes VI, VII and X are 
written in (CP/M) M Basic and Disk Extended 
Microsoft Basic. Other programs written in 8K 
Basic. 



dd $1.50 per volume handling, all domestic shipments sent U.P.S. except APO and 
0. Box which go parcel post. Foreign orders add $6.00/volume lor air shipment and 
ake payable in U.S. dollars only. 

MAILABLE AT MOST COMPUTER STORES 

faster Charge and Bank Americard accepted. 

)ur Software is copyrighted and may not be reproduced or sold. 

Jnlike others we have NOT raised our prices in five years 



KEMCO, LTD. 

P.O. Box 2096L Ashland, VA 23005 

Sales HOT LINE 1-804-798-1147 

IN GERMANY 

Ing. W. Hofacker, GmbH 
Holzkirchen, W. Germany 



IN HOLLAND 

Nanton Press B.V. 
Bilthoven, Holland 



OVER 116, 



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CJ CM OJ W CM CJ CM CJ CM Cvl CJ CJ <"J CJ 



156 January 1981 © BYTE Publications Inc 



Why is the 88G Printer 
the new industry 

leader? 



QUALITY 

The attractive, durable 88G casework is 
formed from impact-resistant, flame- 
retardant Styron. Microprocessor con- 
trolled stepper motors provide precision 
control over print head and paper 
positioning. Computer quality tractors 
position paper for readability and are 
fully adjustable to accommodate varying 
paper widths. 





MICROPROCESSOR 
CONTROLLED INTERFACE 

The microprocessor array provides the 
intelligence for a dual RS232 serial 
and a Centronics® type parallel interface. 
Both inputs are fully buffered to allow 
the 88G to receive data and print 
simultaneously. A IK character buffer is 
standard with a 2K buffer available as 
an option. 

The short line thruput of the 88G has 
been increased by incorporation of a 
Quick Cancel feature that fully utilizes 
the bidirectional/unidirectional printing 
capabilities. Built-in diagnostic and 
self-test capabilities allow the user to 
easily pinpoint system problems and 
a Power On confidence 
test verifies 
operational status of 
the printer each 
time power is applied 



VERSATILITY 

The 88G prints a full upper and lower 
case 96 character ASCII set with a crisp, 
clear 7x7 matrix in 80, 96, or 132 column 
formats. For text processing and 
correspondence applications, an 11x7, 
80 column serif style matrix can be 
selected by switch or software command. 
The dual tractor/pressure-feed paper 
drive system allows the user to choose 
either pin-feed, roll, or single sheet 
papers up to 9.5 inches wide. 

Complete forms control allows the 
88G to be quickly configured for printing 
single or multiple-ply invoices, purchase 
orders, checks, or any type of preprinted 
form. Optional paper roll holders and 
single sheet feeders can be quickly 
attached. 

The wide use range of the 88G makes 
it the perfect companion for business 
systems, data processing, RO teleprinter 
and terminal printer applications. 

GRAPHICS 

A high-resolution, dot-addressable 
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screen graphics, drawings, illustrations, 
etc. Single dot print resolution greatly 
extends the usefulness of the graphics 
capability. Selection of one of the 
four horizontal dot densities available 
customizes the graphic printout, and 
alphanumerics can easily be included 
for titling of graphs and illustrations. 



LONG LIFE 
RIBBON CARTRIDGE 

Ribbon difficulties are minimized 
through use of a continuous loop cart- 
ridge with a five million character life. 
It is easily changed without opening 
the case, and without any complicated 
or messy threading operations. 




PRICE 

Every detail is directed toward providing 
a heavy-duty, commercial quality 
printer for only $749.00. No other printer 
on the market today can provide its 
quality, features and performance at 
a comparable price. The 88G is an 
obvious industry leader. 





^Centronics is a registered trademark of the Centronics Data Computer Corp. 



Circle 100 on Inquiry card. 



Micro Peripherals, Inc. 
4426 South Century Drive 
Salt Lake City, Utah 84107 
Phone (801) 973-6053 



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iT. iT. ij 1 . ij'. 



158 January 1981 © BYTE Publications Inc 



Circle 101 on inquiry card. 



00MPUS1AR 

INTERTEC S NEW $2500 MULTI-USER SMALL BUSINESS COMPUTER 



At last, there's a multi-user micro- 
computer system designed and built the 
way it should be. The CompuStar™. Our 
new, low-cost "shared-disk" multi-user 
system with mainframe performance. 

Unlike any other system, our new 
CompuStar offers what we believe to be the 
most practical approach to almost any 
multi-user application. Data entry. Distrib- 
uted processing. Small business. Scientific. 
Whatever! And never before has such 
powerful performance been available at 
such modest cost. Here's how we did it . . . 

The system architecture of the 
CompuStar is based on four types of video 
display terminals, each of which can be 
connected into an auxiliary hard disk stor- 
age system. Up to 255 terminals can be 
connected into a single network! Each ter- 
minal (called a Video Processing Unit) con- 
tains its own microprocessor and 64K of 
dynamic RAM. The result? Lightning fast 
program execution! Even when all users 
are on-line performing different tasks! A 
special "multiplexor" in the CompuStar 
Disk Storage System ties all exter- 
nal users together to "share" the 
system's disk resources. So, no 
single user ever need wait on an- 
other. An exciting concept . . . 
with some awesome application 
possibilities! 

CompuStar™ user 
stations can be configured in 
almost as many ways as you 
can imagine. The wide variety 
of terminals offered gives you 
the flexibility and versatility 
you've always wanted (but 
never had) in a multi-user 
system. The CompuStar 
Model 10 is a program- 
mable, intelligent terminal 
with 64K of RAM. It's a 
real workhorse if your re- 
quirement is a data entry 




or inquiry/response application. And if your 
terminal needs are more sophisticated, 
select either the CompuStar Model 20, 30 
or 40 Each can be used as either a stand- 
alone workstation or tied into a multi-user 
network. The Model 20 incorporates all of 
the features of the Model 10 with the 
addition of two, double-density mini-flop- 
pies built right in. And it boasts over 
350,000 bytes of local, off-line user stor- 
age. The Model 30 also features a dual 
drive system but offers over 700,000 bytes 
of disk storage. And. the Model 40 boasts 
nearly 1 % million bytes of dual disk stor- 
age. But no matter which model you 
select, you'll enjoy unparalleled versatility 
in configuring your multi-user network. 




Add as many terminals as you like 
- at prices starting at less than $2500. 
Now that's truly incredible! 

No matter what your application, 
the CompuStar can handle it! Three disk 
storage options are available. A tabletop 
10 megabyte 8" winchester-type drive 
complete with power supply and our spe- 
cial controller and multiplexor costs just 
$4995. Or, if your disk storage needs are 
more demanding, select either a 32 or 96 
megabyte Control Data CMD drive with a 
16 megabyte removable, top loading car- 
tridge. Plus, there's no fuss in getting a 
CompuStar system up and running. Just 
plug in a Video Processing Unit and you're 
ready to go . . . with up to 254 more ter- 
minals in the network by simply connect- 
ing them together in a "daisy-chain" 
fashion. CompuStar's special parallel 
interface allows for system cable lengths 
of up to one mile . . . with data transfer 
rates of 1.6 million BPS! 

Software costs are low, too. 
CompuStar's disk operating system is the 
industry standard CP/M*. With an 
impressive array of application soft- 
ware already available and several 
communication packages offered, 
the CompuStar can tackle even your 
most difficult programming tasks. 
Compare for yourself. Of all 
the microcomputer-based multi- 
user systems available today, 
we know of only one which 
offers exactly what you need 
and should expect. Excep- 
tional value and upward 
growth capability. The 
CompuStar™. A true price 
and performance leader! 

3NTE3TEC 

Edata 
ssystems® 



2300 Broad River Rd Columoia SC 29210 
1803} 798-9100 TWX 810-666-2115 



•flegtsteiMl uaacmaii □' Chgirai flesea/cn Inc ^^ 



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160 January 1981 © BYTE Publications Inc 



Circle 102 on inquiry card. 



Pump Up Your TRS-80 with the ES/F Mass Storage System 





THESE FACTS SPEAK FOR THEMSELVES! 



CASSETTE ES/F 



MINI-DISK 



MEET 

THE WAFER 



SPEED 

(Seconds to 
load "Blackjack") 



56 



6 

(5' wafer) 



%Vz 




CAPACITY 

(thousands 
of bytes) 



38 
(C-20) 



64 
(75' wafer) 



59 

(TRSDOS) 



RELIABILITY 

(Designed for 
digital data?) 



NO 



YES 



YES 



▲ Actual Size 



Actual Thickness T 



SYSTEM COST 

(First unit 
plus interface) 



$60 



$250 



$800 




MEDIA COST 

(in quantities 
often) 



$3.10 
cassette 



$3.00 
wafer 



$3.20 
disk 



Let's face it. Cassette players were not 
designed to store digital data and pro- 
grams. That's why we designed a digital 
storage system using a continuous tape 
loop: the Exatron Stringy /Floppy 
(ES/F) and the Wafer. There's no ex- 
pensive interface to buy-the ES/F 
comes ready to pump up your TRS-80.* 

Once your TRS-80* is pumped up by 
our ES/F . . . you won't want to deflate 
it. We're so sure, that we offer an 
unconditional 30-day money-back 
guarantee and a one-year limited war- 
ranty. Over 2,000 TRS-80 * owners have 
met the wafer . . . why don't you'll ' 



EXATRON 
STRINGY/Fl 

SPEED, CAPACITY 
AND RELIABILITY 
FOR ONLY $249.5 



f 




CALL 

OUR HOTLINE 

(800)-538-8559 

IN CALIFORNIA. 
CALL (408)-737-71 11 






^ 

<*»«"" 




exatron, inc. 



Commercial Street 
ivvale. Calif. 94086 



•TRS-80 is a registered trademark 



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•3 u:i o in 



162 January 1981 © BYTE Publications Inc 



Circle 103 on inquiry card. 



Orange micro 



'SPECIALIZING IN PRINTERS 
AND CRT'S" 



CENTRONICS 737 (SS) 

Word Processing Print Quality 




• 18 x 9 dot matrix; suitable for word 
processing • Underlining • proportional 
spacing • right margin justification • serif 
typeface • 50/80 CPS • 9 1 /2" Pin 
Feed/Friction feed • Reverse Platen • 
80/132 columns 



MALIBU 




The Smail Business Printer; 
Letter Quality & Speed. 

• 10 x 9 dot matrix • Letter quality print; 
Lower case descenders • High speed; 165 
CPS, Bidirectional, Logic seeking • Wide 
carriage, Adjustable tractors to 16" • 
Vertical forms control • Variable line spac- 
ing • User programmable character set • 
Dot Resolution Graphics 



CENTRONIC 737-1 (List $995) 



SCall 



MALIBU 165 (List $2495) 



$2195 



EPSON MX80 




Low-Priced 
Professional Print Quality 

• 9 x 9 dot matrix • Lower case descenders 

• 80 CPS • Bidirectional, Logic seeking • 
40, 66, 80, 132 columns per line • 64 special 
graphic characters: TRS-80 Compatible • 
Forms handling • Multi-pass printing • Ad- 
justable tractors 



EPSON MX80 (List $645) 



SCall 



OKIDATA MICROLINE SERIES 

TRS-80 Graphics Compatibility 



• 9 x 7 dot matrix • 80 CPS • 80, 132 
columns — 64 shapes for charts, graphs & 
diagrams • Double wide characters • 6/8 
lines per inch • Up to 3 part copy • Friction 
& pin feed • 200 M character head warranty 




OKIDATA MICROLINE 80 (List $800) 



$599 



BASE 2 

The Hobbyist Printer With The Most Features 

• Graphics • Tractors/Friction Feed • 2K 
Input Buffer • RS-232 Serial, Centronics® 
Parallel, IEEE-488, 20 ma • TRS-80 Cable 
option • 100 CPS • Fast form feed • User 
programmable character set • 64, 72, 80, 
96, 120, 132 Columns/line • Expanded 
characters • Automatic skip-over-perfora- 
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grammable vertical line spacing • Intel 
8085 Microprocessor — over 40 software 
commands 
(List $699) $649 




BASE 2 800B 



TOLL FREE 
(800) 854-8275 

CA,AK, HI (714) 630-3322 

At Orange Micro, we try to fit the right printer to your application. 
Call our printer specialists tor free consultation. 



ANACOM 

Low Cost, High Speed, Wide Carriage 

• 9 x 9 dot matrix • Lower case descenders • Wide carriage • 
Adjustable tractors to 16" • 150 CPS, Bidirectional, Logic Seeking 



ANACOM 150 (List $1350) 



SCall 



EPSON TX80 



• 5 x 7 dot matrix • 125 CPS • Double wide characters • Dot 
resolution graphics & 64 special graphic characters • 6/8 line per 
inch • Vertical forms control • Adustable tractors • Heavy Duty — 
Highly reliable 



EPSON TX80 (List $799) 



SCall 



THE SMALL COMPUTER PRINTER by Brent Weston 

This illustrated booklet provides the information you need about today's small 
printers. There are many printers available, each with different features and 
capabilities. The Small Computer Printer will guide you in determining which 
printer best fits your applications. A complete feature comparison chart is 
included representing over 40 small printers. A printer is a big investment — 
learn all about them before you buy one. $795 





TELEVIDEO CRT'S 

PRICES SLASHED! 

TVI912C") Please Call Toll Free 
_ > Prices are too low to 
TVI 920C J advertise 



PRINTERS 

J CENTRONICS 730 Radio Shack Line Printer II (List $795) $ 639 

I OKIDATA MICROLINE 82 & 83 $ Call | 

l NEC 5530-5 letter quality, RO, parallel, tractors (List $2970) $ 2599 1 

PAPER TIGER IDS 440 w/graphics and 2K buffer . . (List $1094)$ 939 1 
PAPER TIGER IDS 460 w/graphics, 9 x9dot matrix . . (List $1295)$ Call! 
QUME 5/45 typewriter quality (List $2905) $ 2559 j 

INTERFACE EQUIPMENT 

APPLE II -BASE 2 parallel graphics interface board & cable $ 160 

APPLE II- EPSON TX80 

■ parallel graphics interface board & cable $ 110 ; 

SSMAIO BOARD Apple Serial/parallel interface (List $225)$ 175 1 

MICROTRONICS Atari parallel interface $ 69' 

ATARI 850 Interface module, serial/parallel $ 199 1 

, TRS-80 CABLES to keyboard or Exp. interface * Call] 



CALL FOR FREE CATALOG 



-- 



Phone orders WELCOME. Same day 
shipment for VISA, MASTER 
CHARGE, and AMERICAN EX- 
PRESS. Personal checks require 2 
weeks to clear. Add 3% for ship- 
ping and handling. California resi- 
dents add 6%. Manufacturer's 
warranty included. Prices subject to 
revision. 



Orange 

flllCfO, Inc. 

3148 E. La Palma, Suite E 
Anaheim, CA 92806 



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164 January 1981 © BYTE Publicaeions Inc 



dBASE II vs. the Bilge Pumps. 



by Hal Pawluk 

We all know that bilge pumps suck. 

And by now, we've found out— the hard 
way— that a lot of software seems to work the 
same way. 

So I got pretty 
excited when I ran 
across dBASE II, an 
assembly-language rela- 
tional Database Man- 
agement System for 
CP/M. It works! And 
even a rank beginner 
like myself got it up 
and running the first 
time I sat down with it. 

If you're looking 
for software to deal with 
your data, too, here are 
some tips that will help: 

Tip #1: Database Management 
vs. File Handling: 

Any list or collection of data is, loosely, 
a data base, but most of those "data base man- 
agement" articles in the buzzbooks are really about 
file handling programs for specific applications. 
A real Database Management System gives you 
data and program independence (no repro- 
gramming when data changes), eliminates data 
duplication and makes it easy to turn data into 
information. 

Tip #2: Assembly 
Language vs. BASIC: 

This one's easy: if you're setting up a 
DBMS, you're going to be doing a lot of sorting, 
and Basic sorts are s-l-o-w. Run a benchmark on 
a Basic system like S*-IV against a relational 
DBMS like dBASE II and you'll see what I mean. 
(But watch it: I've also seen one extremely slow 
assembly-language file management system.) 

Tip #5: Relational vs. Hierarchal 
& Network DBMS. 

CODASYL-like hierarchal and network 
systems, around since the 1960's, are being 
phased out on the big machines so why get stuck 
with an old-fashioned system for your micro? A 
relational DBMS like dBASE II eliminates the pre- 
defined sets, pointers and complex data structures 
of a CODASYL-type DBMS. And you don't need 
to be a programmer to use it. 

Circle 104 on inquiry card. 




dBASE II vs. everything else. 

dBASE II really impressed me. 
Written in assembly language (with no 
need for a host lan- 
guage), it handles up to 
65,000 records (up to 32 
fields and 1000 bytes 
each), stores numeric 
data as packed strings 
so there are no round- 
off errors, has a super- 
fast multiple-key sort, 
and supports ISAM 
based on B* trees. 

You can use it 
interactively with 
English-like commands 
(DISPLAY 10 PROD- 
UCTS), or program it 
(so when you've set up the formats, your secretary 
can do the work). Its report generator and user- 
definable full screen operations mean that you can 
even use your existing forms. 

And if all this makes your mouth water, but 
you've already got all your data on a disk, that's 
okay: dBASE II reads your ASCII files and adds 
the data to its own database. 

Right now, I'm using dBASE II with my 
word processor for budgeting, scheduling and 
preparing reports for my clients. 

Next come job costing, time billing and 
accounting. 

An Unheard-of Money-Back 
Guarantee. 

dBASE II is the first software I've seen 
with a full money-back guarantee. 

To check it out, just send $700 (plus tax in 
California) to AshtonTate, 3600 Wilshire Blvd., 
Suite 1510, Los Angeles, CA 90010. (213) 666-4409. 
Test dBASE II doing your jobs on your computer 
for 30 days. If, for some strange reason, you don't 
want to keep it, send it back and they'll refund 
your money. 

No questions asked. 

They know you don't need your bilge 
pumped. 



Ashton-Tate 



©Ashton-Tate 1980 



BYTE January 1981 165 



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166 January 1981 © BYTE Publications Ire 



THE UNBEATABLE S-100 
MEMORY I 






Mi W i tfiijiiidiiiiaia 






DBOOttC 



■ 



,,,,,,........ 



J/ffiiii/MiiHiiffilT^^ 




That's the MEASUREMENT systems & con- 
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bank addressable on any 16K boundary. 



Systems 



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a Division of MEASUREMENT systems &. controls 

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Outstanding features such as those listed 
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• Four independent 16K software select- 
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• Each bank is independently addressable 
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• Switch selectable bank sizes — from 
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• Eight banks (51 2K) per I/O port for each 
of the 256 ports. 

• Z-80 4MHz operation with no wait 
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• On-board diagnostic LED's. 

• Low power — 8 watts maximum. 

• Reliable, tested and burned-in memory. 

• IEEE S-100 compatible timing. 

• One year guarantee. 

• Attractive Dealer & OEM Prices. 

See your nearest computer dealer, or contact 
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TWX/TELEX: 678 401 TAB IRIN 



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168 January 1981 © BYTE Publications Inc. 



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BYTE January 1981 169 



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170 January 1981 © BYTE Publications Inc 



We're 

known 

for our 

fine print. 



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BYTE January 1981 



171 



Circle 108 on inquiry card. 



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Listing 1 continued: 



5045 
5058 

5855 
5068 
5065 
5078 
5075 
5080 
5685 
5098 
5095 
5108 
5105 
5118 
5115 
5120 
5125 
5130 
5135 
5 140 



1> INDEX OF FIRST POSITION {INTEGER) 

2HNDEX OF LAST POSITION (INTEGER) 

3>KEV TO EE FOUND CSTRING) 

4) STRING ARRAY IN WHICH THE SEARCH IS MADE 



DEF FN 
1NTEG 
F=I 

L=J 

M=t.F + 
IF Q* 
IF Q* 
IF Q< 
IF F< 
M = 8 
RETUR 
FNEND 



S< INTEGER I, J,Q*, A*C*> > 

ER F,L, M 



L> DIV 2 

=A*<M> THEN RETURN M 
>A*<M> THEN F=M+1 
<fl*<M) THEN L=M-1 
=L THEN 5890 

N M 



** END OF BAR 



I FIND CENTER OF ARRAY 

!IF KEY HAS BEEN FOUND, RETURN INDEX 



'CONTINUE SEARCH THROUGH APPROPRIATE HALF 
! RETURN IF SEARCH FAILS 



:iDE GENERATION PROGRAM ***************** 



Text continued from page 150: 

Since the HP-41C instructions are 
of varying length, they quite often 
straddle the border between two rows 
of bar code. If an instruction starts in 
the previous row and ends in the cur- 
rent row, the bytes of the instruction 
contained in the current row are the 
leading partial-function bytes. Alter- 
nately, if an instruction starts in the 
current row and ends in the next row, 
the bytes contained in the current row 
are the trailing partial-function bytes. 
The third byte of a bar-code row con- 
tains, in the 4 high-order bits, the 
number of leading partial-function 
bytes, and, in the 4 low-order bits, 
the number of trailing partial-func- 
tion bytes. 



A Bar-Code Generating Program 

The program given in listing 1, 
which runs on a Hewlett-Packard 
HP-9845 minicomputer, allows the 
user to enter numbered HP-41C in- 
structions and will insert the instruc- 
tions into a text string for later use. 
Each instruction is associated with a 
value between 1 and 2240, which 
determines the order of execution of 
the HP-41C instructions. The number 
2240 is given as a maximum since that 
is the largest number of bytes avail- 
able to the user in program memory. 

If the HP-41C program is extremely 
long, a renumbering command allows 
the user to create gaps in his number- 
ing scheme to allow for later insertion 
of instructions. Using this program, 
the user is able to insert, delete, and 
replace instructions; the user can save 
the program in a file for later use. 

In response to the prompt symbol, 
the user may give other single-word 
commands to compile and generate 



bar code for the HP-41C programs, 
save and retrieve the compiled HP- 
41C machine language, and list or 
delete the entire program. The syntax 
and action of each command are 
given in table 2 and will be printed 
out by the program if a "77" is typed 
in response to the prompt symbol. 

The basic structure of the program 
is a main routine that generates the 
prompt symbol and decodes the 
input. A series of other routines per- 
form the command functions and are 
called by a jump table in the main 
routine. The input to the main rou- 
tine is decoded only to the extent of 
determining whether a command or 
an instruction has been given, and if 
an instruction has been decoded, the 
instruction number is calculated. The 
instruction is then appended to a text 
string, and a pointer to that instruc- 
tion is entered into a pointer array at 
the position given by the instruction 
number. Consequently, the other 
routines will be able to retrieve the 
program by a linear inspection of the 
pointer array. 

Replacement, deletion, and renum- 
bering of instructions only involve 
manipulation of the pointer array, 
while insertion requires that the in- 
struction number (an integer) must 
fall between two existing instruction 
numbers. The syntax of the HP-41C 
instructions recognized by this pro- 
gram follows that of the HP-82143A 
thermal printer and of the program 
listings distributed by the HP User's 
Library, with a few exceptions dic- 
tated by the difference between 
ASCII and the HP-41C character set. 
For example, characters representing 
the Greek letter E, the angle sign, and 
the =£ sign are represented by the 

Text continued on page 178 



172 January 1981 © BYTE Publications Inc 







fey 



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Professionals and Hobbyists 



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COMPILE 
DELETE n 
EXIT 
GETPROG 

GETTEXT 

LIST 
NUMBER 

RENUMBER 

RUN 

RUNPRIVATE 
SAVEPROG 

SAVETEXT 



Bar-Code Generator Commands 

Compiles the current program and loads the compiled code into the array M. 

Deletes the instruction given by n from the current program. 

Halts execution of the bar-code generator or of the line-number generator. 

Retrieves compiled code from a file on cassette tape. (The routine prompts for a 
file name.) 

Retrieves program instructions from a file on cassette tape. (The routine prompts 
for a file name.) 

Lists the entire current program. 

Automatically generates instruction numbers for HP-41C program entry. The start- 
ing number and size of the increment are requested by the routine. This routine is 
halted by typing "EXIT". 

Renumbers the current program instructions. (The routine prompts for the old 
starting number, new starting number and size of the increment.) 

Generates the bar code from the compiled code. (It may not be run unless com- 
piled code has been generated.) 

Generates bar code for a private program. 

Stores compiled code for the current program on cassette tape. (The routine 
prompts for a file name.) 

Stores instructions of the current program on cassette tape. (The routine prompts 
for a file name.) 



SCRATCH Erases the current program. 

?? Displays a list of available commands and syntax rules. 

Table 2: A table of commands for the bar-code generating program given in listing 1. 



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174 January 1981 © BYTE Publications Inc 



Circle 109 on inquiry card. 



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"ll 



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ROW 6 (14-16) 



ROW 7 (16-20) 



ROW 8 (20 - 24) 



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Figure 2: A demonstration program for the HP-41C. This bar-code program was created by an HP-9845 minicomputer connected to a 
Diablo 1650 printer using a Titan 10 metallic daisy-wheel. The program requires twenty registers within the HP-41C. 



I The I 



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176 January 1981 © BYTE Publications Inc 



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Text continued from page 172: 

ASCII characters &, @, and #, 
respectively. Also, single quotes in- 
stead of double quotes are used for 
text and alphanumeric labels, and an 
alphanumeric append instruction is 
indicated by the character A pre- 
ceding the single quotes and character 
string. The most important routines 
called by a command are the compile 
routine, which decodes the current 
program held in the text string, and 
the run routine, which takes the com- 
piled machine code and generates the 
bit pattern representing the required 
bar code. 



The program listed here was 
developed on an HP-9845A minicom- 
puter and contains the functions and 
output statements required to gen- 
erate bar code on the Diablo 1650 
daisy-wheel printer. This is the 
system used by the HP User's Library 
to produce bar code at request for 
any program written either for the 
HP-41C or for the HP-67 and HP-97 
series. The Diablo 1650 printer is used 
with a 96-character Titan 10 metallic 
daisy wheel and a Hytype II multi- 
strike film ribbon. 

The bars are printed by using the 
vertical bar (about 160 mils tall and 9 




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mils wide) on the Titan 10 with a 
horizontal increment of 1/120 inch. 
The narrow bars are two characters 
wide, the wide bars are four char- 
acters wide, and the spaces are three 
blanks wide. Three blanks are used 
instead of two because the ink 
generally spreads a slight amount, 
causing the spaces to shrink and the 
bars to grow larger. The paper used is 
the standard one-ply, 8V4 by 11 inch, 
white computer paper. Figure 2 con- 
tains the bar code generated by the 
User Library's Diablo 1650 for a short 
demonstration program written for 
the HP-41C. 

The subroutine at line 1605 prints a 
row of bar code and clears certain 
variables in preparation for the next 
row of bar code; this routine must be 
changed by the user if a different 
computer/printer combination is 
used. Copies of the resulting bar code 
may be made by an office copier if 
careful attention is paid to contrast, 
sharpness, and bar width. Many of 
the less expensive copy machines 
shrink the size of the bars, thus 
expanding the size of the spaces and 
rendering the bar code unreadable. 
Most of the commercial printing 
houses have the better copiers needed 
for this purpose. If many copies are 
needed, offset printing may also be 
used as a more expensive but very 
reliable method for bar-code repro- 
duction. 

For further assistance in generating 
bar code, you can obtain the Hewlett- 
Packard Creating Your Own HP-41C 
Bar Code manual (part number 
82153-90019), which contains a 
listing of the program given here and 
a discussion of bar codes and bar- 
code generation. ■ 



Editor's Note: 

The Hewlett-Packard bar-code format is 
partially compatible with the PAPER- 
BYTE 9 format designed by BYTE Publica- 
tions Inc in 1977. Fortunately, the com- 
patibility is in the most important place, the 
representation of 1 and bits within a line 
of bar code. Although Hewlett-Packard 
uses different header and trailer bytes to 
frame the actual bytes of data, the encoding 
scheme used to encode both the data and 
the header and trailer bytes is the same in 
both Hewlett-Packard bar codes and 
PAPERBYTE® . Hewlett-Packard's deci- 
sion in this direction strenghtens the 
authority of the PAPERBYTE 9 format, 
and we feel that this is an important step 
toward the standardization of machine- 
readable bar code.... GW 



178 January 1981 © BYTE Publications lnc 



Circle 113 on inquiry card. 



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Circle 114 on inquiry card. 



BYTE January 1981 179 



When You Have To 
Face A Deadline 




Communication Arts. Huntington Beach. CA 



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We ship on 8" single density and 5-1/4" North Star single density. 
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CP/M is a r egister ed trademark of Digital Research MP/M is a trademark of Digital Research Pascal/Ml"-*- is a registered trademark of MT Micro Systems 



MT MicroSYSTEMS SOFTWARE ARSENAL: 





Pascal/MT+ ( 



Screen 
Editor* 

'Contact us tor the exciting news about this leap forward in state ot the art technology. 




Pascal/MT+® provides you with the power to meet your 
deadlines head-on! Compiling directly to native code without 
slowing down to generate P-code or assembly language, 
Pascal/MT+® generates ROMable, optimized native code and 
gives you the flexibility ot modular compilation; and it does 
so at speeds up to 1000 lines per minute while the others are, 
at best, one third as tast! Even when you're not facing a 
deadline, Pascal/MT+® never wastes your time! Nobody likes 
to wait for a computer. The Pascal/MT+® won't keep you 
waiting! Your software written in Pascal/MT + ® is totally 
portable to most 8 and 16 bit processors. The Pascal/MT+® 
system provides you with a powerful debugging tool. With 
Pascal/MT+® you do have an effective weapon against 
monstrous deadlines. 

Pascal is the most popular programming language in use 
today. You can use Pascal/MT+® to replace assembly 
language in your ROM based applications, BASIC and COBOL 
in your business applications, FORTRAN in your scientific 
applications, or interpreted Pascal in all of your appiications. 
Because Pascal programs are easy to write, read, and 
maintain; and because the Pascal/MT + ® system contains all 
of the features you need for your applications, you can get 
your job done on time! In fact, you may never need assembly 
language or any other high level language again. 
Pascal/MT+® has the speed, extensions, and portability to 
stock your software arsenal for years to come!!! 



ISO STANDARD Pascal 

Pascal/MT+® supports the ISO Standard. We send the results 
of our compiler's performance on the Validation Suite. Also, 
for portability the MT+ compiler can warn you when you are 
using non-standard extensions. 



Modular Compilation 

Pascal/MT+® generates the same industry standard relocat- 
able code used in FORTRAN and PL/I. Both Pascal and 
assembly language modules may be separately compiled 
and then combined to produce a final program. With modular 
compilation available, the run time overhead is as small as 
256 bytes and is typically 1200 bytes. 



Native Code Generation 

Pascal/MT+® native code is faster than interpreted Pascal 
and other native code Pascals in benchmark test programs. 
Optimization steps taken during compilation perform such 
enhancements as removing redundant PUSH/POPsequences 
and using single increment and decrement instructions when 
adding or subtracting small literal numbers. In addition, our 
disassembler interleaves your Pascal source code and 
symbolic assembly code to help you write more efficient 
programs. 



Extras 

• Predeclared a-rays INP and OUT directly access I/O ports. 

• INLINE instruction for inserting assembly language between the Pascal 
statements. A built-in mini assembler translates the instructions at 
compile time. Constant tables may be generated using the inline facility. 

• ABSOLUTE assembly language procedure declarations for using pre- 
assembled routines. 

• INTERRUPT procedures. 

• CHAINING for transfering control from one program to another. 

• ELSE clause on the case statement. 

• REDIRECTED I/O facilities allow user written character level I/O drivers to 
be called via READ and WRITE statements. 

• HEX literal numbers are supported. 

• Built in procedures/functions: 
—bit test, clear, set. 

—byte swap. 

—return hi or lo byte. 

—Shift left and right. 

—Return the address of a data item or routine. 

—Return the size of a data item. 

—Enable, disable interrupts. 

—All standard file I/O plus random read and write to files. 

• Include files supported. 

• Source code for run-time package included. 

• Business (18 digit) arithmetic. 

• Scientific (6.5 digit) arithmetic. 

• AMD 9511 hardware support. 

• Transcendental functions. 

• Full string capability (UCSD compatible). 

Symbolic Debugger 

Our symbolic debugger is optionally linked into the final program. If you're 
tired of feeling like you're in the dark when using a higher level language, the 
Pascal/MT* 19 debugger lights up the darkness. The debugger traces one or 
more lines of Pascal code or executes the program until a line number or 
symbolic breakpoint is reached. To follow program flow the name of each 
procedure and function entered is displayed by the debugger. The contents of 
simple and complex variables may be displayed by name. The debugger may 
be used in a ROM environment so that program flow and variable contents are 
visible. 

Distribution disk contains 

• BCD compiler configured for your target machine. 

• Floating point compiler configured for your target machine. 

• Linker. 

• Interactive Symbolic Debugger. 

• Run time package in source and object form. 

• Pascal library and utility routines. 

• Manual containing an Applications Guide and a Language Guide. 

• Sample programs. 

System Requirements 

• Operating System: CP/M® (or equivalent such as CDOS. IMD0S, etc.) 

• Memory requirements:52Kminimum. 

• Host Machines: 8080 or Z80. 

• Target Machines: 8080/Z80. 68000, Z8000, 8086/8088, 6809. 

• Resident compilers for all processors will be forthcoming as operating 
systems become available. 

MT MicroSYSTEMS has a very reasonable, graduated, one time royalty 
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Ordering 

8 bit processor target machines: 

8080/Z80, 6809 S250.00 each 

16 bit processor target machines: 

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Copies on North Star Disks $50 additional. 
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(refundable with system purchase): $30.00 

Note: Not all 16-bit CPU code generators are available at Ibis time: contact us (or information 
before ordering. 



OEM and Dealer inquiries invited. 



Circle 115 on Inquiry card. 



Systems Notes 



Numerical 
Analysis for 
the TRS-80 
Pocket Computer 

Mike Salem, 26A Delancey St, London NWl 7NH, England 



Complicated programs can often be easily modified to 
fit into the new pocket computers. I've taken three pro- 
grams from the December 1979 issue of BYTE and 
modified them to run on the Radio Shack TRS-80 Pocket 
Computer (sold as the Sharp PC-1211 outside of the 
United States). The Pocket Computer has a 24-character 
LCD (liquid-crystal display), twenty-six fixed variables, 
and 1424 bytes of programmable memory. 

One of the programs I modified was the discrete- 
Fourier-transform program that appeared in "Frequency 
Analysis of Data Using a Microcomputer" by F R 
Ruckdeschel (December 1979 BYTE, page 10). I also com- 
bined two programs that compute the time-domain 



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Formats: Any 8" single or double density. TRS-80 Mod II, Northstar 
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Runs on Beehive. Soroc. Hazeltine. ADDS, Televideo, SOL, TRS-80 
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response of a system with a given transfer function into a 
single program ("Noniterative Digital Solution of Linear 
Transfer Functions" by Brian Finlay, December 1979 
BYTE, page 144). The modified programs have all of the 
features of the originals, with the obvious omissions of 
printing and plotting. 

Incidentally, it is important to note that the TRS-80 
Pocket Computer, in common with many machines, 
allows BASIC lines to contain multiple statements (sav- 
ing 3 bytes of programmable memory for each line 
number omitted). Although this feature is useful in itself, 
the TRS-80 Pocket Computer also has an IF statement 
that can control all of the remaining statements in the 

Listing 1: A discrete-Fourier-transform program for the TRS-80 
Pocket Computer. This program was modified from "Frequency 
Analysis of Data Using a Microcomputer" by F R Ruckdeschel 
(December 1979 BYTE, page 10). Statements entered on the 
same line are separated here for clarity. 



10 

11 

190 

250 



290 



340 



370 



410 
420 



510 
710 



770 
800 

810 

815 
820 



REM BYTE DEC 79 

RADIAN 

INPUT "1ST X? ";Z,"LAST X? ";Y,"#OF POINTS? ";N 

1=1 

INPUT "I/P SCALE FACTOR? ";I 

IF I< 1 GOTO 250 

D = (Y-Z)/(N-1) 

Q = 

V = i/DI 

U = V/(N-1) 

FOR 1=1 TON 

PAUSE "NEXT § = ";I 

BEEP 1 

INPUT "NEXT F(T) VALUE? ";0 

A(I + 26) = 

NEXT I 

B = 

FORI = 27TON + 26 

IFB>A(I)LETB = A(I) 

NEXT I 

FORI= 27TON + 26 

A(I) = A(I)-B 

NEXT I 
B = ABSB 
T = 

FORI = 27TON + 26 
IFT<A(I)LETT = A(I) 
NEXT I 

FOR 1=1 TON 
W = (I-1)*U 
C = 
P = 

FORM=l TON 

X = Z + (M-1)*D 

G = WX 

C = C + A(M + 26)*COSG 

P = P + A(M + 26)*SING 

NEXTM 
F = V(PP + CC)*D 
IF 1=1 LETC = C-NB 

F = D*ABSC 
BEEP 1 

PRINT U*(I-1);"RAD/S" 
PRINT "AMPL. = ";F 
IF C<>0 LET O = ATN(P/C)*180/tt 

PRINT "PHASE = ";0 
NEXT I 
BEEP 3 

PRINT "END OF RUN" 
END 



182 January 1981 © BYTE Publications Inc 



Circle 124 on inquiry card. 



One Stop 
Shopping 




New CPU Card 
Completes the 
Package. 

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rounds out its product line. Along with the single or 
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and the S-100 bus in the cabinet, this new CPU board 
means that Tarbell now offers everything needed to 
build a system. Just add a CRT and printer, and you're 
in business. Tarbell is now your one-stop shopping 
source. 

One of the outstanding features of this new CPU board 
is memory-management hardware that allows dynamic 
mapping of logical to 1 Megabyte of physical memory in 
4K blocks. Moreover, the CPU board is especially 



designed to make it easier to implement multi-user 
operating systems, such as MP/M™ from Digital 
Research. It can run at 2 or 4Mhz, jumper selectable. It 
has two RS-232 Serial Ports (one for printer and one for 
CRT), with full handshaking capability. 

One of its additional important features is a crystal- 
controlled programmable timer, which can be used for 
time-of-day clock and multi-tasking operations. 
Programmable priority masked vectored interrupt 
hardware is another useful feature. 

In addition to all the features of the new CPU card, the 
double density floppy interface has DMA which makes 
the multi-tasking operation quite efficient. Also, the 32K 
memory board is static, resulting in a reliable memory. 
The Tarbell System with all three cards can be 
expanded for more memory and thus provides the 
ultimate in flexiblity. 

Now Tarbell has it all. 




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Circle 116 on Inquiry card. 



The One-Stop Shopping Service 



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(213) 538-4251 

MP/M is a trademark of Digital Research. 



BYTE January 1981 183 



Systems Notes, 



same line. Since this makes listings a bit difficult to read, I 
prepared listings 1 and 2 with a separate statement on 
each line.B 

Listing 2: A program for the TRS-80 Pocket Computer that 
computes the time-domain response of a system with a given 
transfer function. The program shown was combined and 
modified from two programs contained in "Noniterative Digital 
Solution of Linear Transfer Functions" by Bryan Finlay 
(December 1979 BYTE, page 144). 



10 
70 



150 
160 



240 
250 



330 



370 



380 



REM "TF: TRANSFER FCN - BYTE DEC 79" 
RADIAN 

INPUT "CONST.? ";K,"#TERMS NUM.? ";E,"#TERMS 
DEN.?";L 
IF E = GOTO 240 

FORG = 27TOE + 26 

O=10 + G 

INPUT "RL, NUM.? ";A(G),"IM, NUM.? ";A(0) 

NEXTG 
IF L = GOTO 330 

FORH = 47TOL + 46 

O=10 + H 

INPUT "RL, DEN.? ";A(H),"IM, DEN.? ";A(0) 

NEXTH 
FOR G = 1 TO L 
= 66 + G 
Q = 76 + G 
A(0)=1 
A(Q) = 
IF E = GOTO 450 

FOR H = 1 TO E 

D = A(26 + H)-A(46 + G) 

C = A(36 + H)-A(56 + G) 

M = V(DD + CC) 



410 

450 
465 

470 

500 

501 

520 
620 



650 



710 



730 



N = ATN(C/D) 

IFD<0LETN = N-i 

A(0) = MA(0) 

A(Q) = N + A(Q) 

NEXTH 
FOR R = 1 TO L 
IF R = G GOTO 501 
D = A(46 + R)-A(46 + G) 
C = A(56 + R)-A(56 + G) 
M = V(DD + CC) 
N = ATN(C/D) 
IFD<0LETN = N-ir 
A(66 + G) = A(66 + G)/M 
A(76 + G) = A(76 + G)-N 
NEXTR 
NEXTG 

INPUT "T(0)7 ";0,"DT? ";S,"# STEPS? ";N 

:T = + NS 

U=-S 

FORQ=l TON 

:U = U + S 

V = 

w=o 

H=l+INT((U-0)/S) 
FOR G = 1 TO L 
X = A(66 + G)*EXP( - UA(46 + G)) 

Y = A(76 + G)-UA(56 + G) 

V = V + X*COS Y 
W = W + X*SINY 
NEXTG 

Z = KV(VV + WW)*SGN V 
BEEP 1 

:PRINT"TIME = ";U 
PRINT "RESP. = ";Z 
;NEXT Q 



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The initial operating system allows the creation of 
your own vocabulary with phonemes (word sounds) 
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Circle 117 on Inquiry card. 



Speed up your PET programming with The BASIC 
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The BASIC Program- 
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when you turn on your PET, it 
uses model TK-80R If you see 
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numbers. For instance, 
to start the line numbers 
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just use RENUMBER 500. 

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[4153 493-TOOL Dealer inquiries invited. 



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Circle 118 on Inquiry card. byte January 1981 185 



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Complete word processor with extensive editing and 

printer formatting features $325 (STANDARD 

TRSDOS VERSION). ..$350 (DIABLO, NEC OR QUME 
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ACCOUNTS PAYABLE, INVENTORY CONTROL, 
INVOICING AND PAYROLL (Small Business Systems 
Group). ..an extensive business system for the serious 
user.. .can be used one module at a time or as a co- 
ordinated system. $225. ..per module. ..$1299 for the 
complete system. 

(3) GENERAL LEDGER, ACCOUNTS RECEIVABLE, 
ACCOUNTS PAYABLE, INVENTORY CONTROL 
AND PAYROLL (Compumax).a complete user ori- 
ented business system. ..can be used one module at a 
time or as a coordinated system. ..$140 per module... 
$995 for the complete system. 

(4) MOD-II UTILITY PACKAGE (Racet Computes)... 
adds important utilities to TRSDOS. ..copy files 
selectively. ..faster and more accurate file copying... 
repair bad directories. ..displays sorted directory of 
all files on 1 to 4 disk drives.. .SUPERZAP.. change 
disk ID. ..and more. ..$150. 

(5) ADVENTURE »1-#9 (Scott Adams - Adventure 
International). ..a series of games formally only 
available on the large computers.. .your goal is to work 
your way through a maze of obstacles in order to 
recover a secret treasure or complete a mission. ..the 
package includes all 9 Adventures written by Scott 
Adams. ..$99. 95. 

(6) GSF (Racet Computers). ..Generalized Subroutine 
Facility.. .a series of super fast machine language 
utilities that can be called from a BASIC program (no 
machine language knowledge required). ..sorts 1000 
items in under 5 seconds., allows PEEK and POKE 
statements. ..move data blocks. ..compress and un- 
compress data. ..works under TRSDOS. $50. 

(7) DSM (Racet Computes)... Disk Sort Merge... sorts 
and merges large multiple diskette files on a 1 to 4 
drive system. ..NOT AN IN MEMORY SORT.. .can 
actually alphabetize (or any other type of sort) 4 disk 
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information in 10 minutes. ..information is provided to 
use DSM with the RS MAILING PROGRAM ...works 
under TRSDOS. ..$150. 

(8) RSM (Small Systems Software)...a machine 
language monitor and disassembler.. .can be used to 
see and modify memory or disk sectors. ..contains all 
the commands found on the Model-I version plus 
some additional commands for the MOD-II. ..works 
under TRSDOS.. .$39.95. 

(9) BLINK BASIC LINK FACILITY (Racet Computes).. 
Link from one BASIC program to another saving all 
variables chain programs without losing variables 
...$50. 

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Computes). ..lists all variables and strings used in a 
program (with the line numbers in which they appear) 
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variables or strings (with the line number in which 
they appear) ..$50. 

(11) DEVELOPMENT PACKAGE (Racet Computes)... 
SUPERZAP (to see. print or change any byte on a 
diskette) ...Disassembler and MOD-II interface to the 



MICROSOFT EDITOR ASSEMBLER PLUS including 
uploading services and patches for Disk I/O. .assemble 
directly into memory.. .save all or portions of source 
to disk. ..dynamic debug facility (ZBUG)...entended 
editor commands. .$125. 

(12) HARD/SOFT DISK SYSTEM (Racet Computes) 
The software essential to interface any of the popular 
large hard disk drives. ..completely compatible with 
your existing software and files. ..allows up to 20 
megabytes of storage (and larger). ..directory expand- 
able to handle thousands of files. ..$400. 

(13) CAMEO HARD DISK DRIVE CONTROLLER... 
coming soon (November 1?) 

{14) HARD DISK DRIVES. coming soon (Nov. 1?). 

(15) H & E COMPUTRONICS, INC. SHARE-A- 
PROGRAM DISKETTE #1... works under TRSDOS. ..a 
collection of programs written by MOD-II owners... 
programs include data base management.. .a word 
processor. ..mail system. ..mortgage calculations... 
checkbook register. ..and many others.. .$8 (add $3 
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GRAM DISKETTE. 

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box of 10). 

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50 diskettes. ..comes complete with index-dividers, tilt 
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(18) MASTER PAC 100... 100 essential programs... 
BUSINESS. PERSONAL FINANCE.. .STATISTICS... 
MATH ..GAMBLING.. .GAMES., includes 125 page 
manual and 2 diskettes.. .$99.95. 

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programs. INVENTORY CONTROL. .PAYROLL... 
BOOKKEEPING SYSTEM. ..STOCK CALCULA- 
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includes 125 page manual and two diskettes. ..$149. 95. 

(20) EDITOR ASSEMBLER (Galactic Software Ltd.)... 
the first user oriented Editor Assembler for the 
MODEL II and was designed to utilize all the features 
of the MODEL II It includes innovative features for 
ease of coding and debugging and complete docu- 
mentation (over 120 pages). ..works under TRSDOS 
...$229.00. 

(21) BASIC COMPILER (Microsoft). ..changes your 
source programs into machine language... increases 
program execution by 3-10 times. ..$395. 

(22) MAIL/FILE SYSTEM from Galactic Software Ltd. 
stores 2,500 names per disk. No sorting time is 
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combination of 19 user codes. Supports an 1 1 digit 
alphanumerica Zip. Supports a message line Comes 
complete with user-oriented documentation (100- 
page manual). Allows for company name and individ- 
ual of a company and complete phone number (and 
extension). ..works under TRSDOS. ..$199. 00 

(23) INCOME TAX PAC. ..Professional income tax 
package. ..most forms and schedules. ..output to video 
or line printer. .automatic memory storage of all 
information. ..data can be loaded from diskette. 
changed and edited ...built in error checking. ..$199. 95. 

(24) COMPUTER GAMES (SBSG) ...Mean Checker 
Machine. Star-Trek III, Concentration, Treasure Hunt. 
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(2) CP/M HANDBOOK. (Sybex). a step-by-step 
guide to CP/M.. .takes the reader through each of the 
CP/M commands., numberous sample programs.. 

practical hints. ..reference tables. ..$13. 95. 

(3) GENERAL LEDGER, ACCOUNTS RECEIVABLE, 
ACCOUNTS PAYABLE, INVENTORY CONTROL, 

AND PAYROLL (Peachtree Software), requires CP/M 
and MICROSOFT BASIC. .professional business 
systems. ..turn key operation ...can be used as single 
modules or as a coordinated system. ..$500 per 
module. ..$2500 for the complete system. 

(4) WORD-STAR. ..The ultimate word processor. ..a 
menu driven word processing system that can be used 
with any printer. All standard word processing 
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(5) MAIL LIST MERGE An add on package that 
allows the user to send form letters (created on 
WORD-STAR) to any compiled mailing list (using any 
CP/M based MAIL program such as the PEACHTREE 
MAIL PROGRAM). ..requires CP/M. WORD STAR and 
andy CP/M based mail program, .,$150. 

(6) SELECTOR III (Micro-Ap)... complete data 
management system.. .user defined fields and codes,, . 
manages any list defined by the user, ..includes 
additional modules for simplified inventory control, 
accounts receivable and accounts payable,. .requires 
CBASIC-2...$295. 

(7) SELECTOR IV (Micro-Ap) the ultimate data 
management system. ..all features use the SELECTOR 
III plus. data file format conversions. .full page report 
formatter, .computations. ..global search and replace 
...hard disk compatible.. .data/text merging. ..$550. 

(8) GLECTOR (Micro-Ap). ..add on package to the 
SELECTOR, ..general ledger that allows the user to 
define a customized chart of accounis...$350. 

(9) CBASIC-2 a non-mtesactive BASIC used for 
many programs that run under CP/M allows user to 
make more efficient use of disk files eliminates the 
use of most line number references, require on such 
programs as the SELECTOR. ..$120, 

(10) MICROSOFT BASIC an enhanced version of the 
MICROSOFT BASIC found on TRSDOS. adds 
commands such as chaining (allows the user to LOAD 
and RUN a new program without losing the variables 
currently in memory). ..long variable length file 
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the BASIC COMPILER to speed up programs (3-10 
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(11) MASTER TAX (CPAids).. professional tax 
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payroll register. W2's and payroll checks. ..$450. 

(13) ELECTRIC PENCIL (Michael Shrayer Software) 
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version) 

(14) BASIC COMPILER (Microsoft) ..changes your 
source programs into machine language, .increases 
program execution by 3-10 times. ..$395. 

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LEVEL II RAM TEST Checks random access memory to ensure that all memory locations are working properly. 

DATA MANAGEMENT SYSTEM Complete file management for your TRS-80'". 

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Languages Forum 



A Bug in BASIC 

W D Maurer, Dept of Electrical Engineering and 
Computer Science, The George Washington University, 
Washington DC 20052 



The purpose of this article is to describe and analyze a 
particular bug that is common to a number of BASIC sys- 
tems for microcomputers. Specifically, of fifteen micro- 
computers surveyed, four of them had this particular bug 
in their BASIC, nine of them did not, and the remaining 
two had the bug in one version of their BASIC but not in 
the other. The bug is illustrated by a simple BASIC pro- 
gram that runs properly on the systems that do not have 
the bug and encounters a run-time error on systems that 
do have it. By comparing the program inputs that cause 
erroneous behavior with those that do not, the cause of 
the bug is traced, and two possible corrections are sug- 
gested. One of these is quite elegant and results in almost 
no change in running time or space requirements. It is, of 
course, rather common for programmers to accuse either 
the hardware or the system software of being at fault 
when their programs have bugs. The analysis here may 
serve as an example of a valid isolation technique of a 
bug's source in system software. 

The program illustrating the bug is shown in listing 1. 
It accepts some numbers from the keyboard, checks for 
the presence of the number 0, and checks for duplica- 
tions. Sample inputs and outputs are shown in listing 2. 
Of the six test cases in listing 2 on page 190, only Test IV 
and Test VI cause problems; both correct and erroneous 
behavior are shown. Table 1 gives the names of the 
microcomputer systems and their respective behavior. 

There are no easy explanations for the presence of this 
bug. As should be evident from table 1 on page 194, 
many of the lowest-priced systems are free from the bug, 

Listing 1: A BASIC program that sometimes causes a NEXT 
WITHOUT FOR error. 

10 DIMT(100) 

20 PRINT "HOW MANY NUMBERS?" 

30 INPUT N 

40 PRINT "INPUT ";N;" NUMBERS" 

50 FOR C = 1 TO N 

60 INPUT T(C) 

70 NEXT C 

80 FOR C = 1 TO N 

90 IFT(C) = 0THEN 130 

100 NEXTC 

1 10 PRINT "ZERO IS NOT PRESENT" 

120 GOTO 140 

130 PRINT "ZERO IS PRESENT" 

140 FORR = lTON-l 

150 FORC = R + lTON 

160 IFT(R) = T(C)THEN210 

170 NEXTC 

180 NEXT R 

190 PRINT "NO DUPLICATIONS" 

200 GOTO 220 

210 PRINT "T(";R;") = T(";C;")" 

220 END 



as are many of the highest-priced systems. A large pro- 
portion of the BASIC systems surveyed, with and with- 
out the bug, were produced by a single software supplier; 
other systems, with and without the bug, were not. We 
draw no general conclusions about the general relative 
suitability of the various systems; many of the systems 
that exhibit the bug have numerous advantages when 
compared to systems that do not have it. 

As we shall see, there are various ways to circumvent 
the bug. That is, we can rewrite the program so that it 
still does the same thing as before, without encountering 
the bug, and we can also do this in a variety of ways. 
This, however, does not change the fact that there is a 
bug. We have the incontrovertible evidence of a simple 
program that clearly ought to run, that does run on nine 
microcomputer systems, and does not run on another 
four systems. 

The bug has to do with FOR... NEXT loops in which 
there are abnormal exits. Many programmers are still 
under the erroneous impression that this is illegal — that 
you are not supposed to jump out of a FOR loop. On the 
contrary, it is illegal to jump into such a loop. Abnormal 
exits from loops are absolutely necessary in programming 
for such tasks as searching (as illustrated here), error 
exits, and, in general, the treatment of special cases. 

Let us now analyze the bug. It is clear from listing 2 
that the problem arises at statement 180. The error 
message, NEXT WITHOUT FOR ERROR IN 180, means 
that there is a NEXT statement (180 NEXT R) that does 
not have a corresponding FOR statement. But this is 
clearly false; there is a corresponding FOR statement (140 
FORR=lTON-l). 

Is the problem the expression N — 1 in statement 1407 If 
statement 140 is changed to 140 Z = N-1 and 145 FOR 
R = l TO Z, the bug is still there. So this is not the prob- 
lem. 

Can we ever get to statement 180 without encountering 
the bug? If we look at Test I, we see the message NO 
DUPLICATIONS. Clearly this was printed at statement 
190, and there are no jumps to 190 in the program, so the 
only way to get to 190 is through 180. Thus, in Test I, the 
computer got through statement 180 with no problems. 

How did we get to statement 1807 There are no jumps 
to 180 in the program either; so we must have gotten 
there from 170 NEXT C. Could this have caused the 
problem? Since the problem is that the system thought it 
was not in a loop when it got to statement 180, we now 
consider the possibility that the system thought it was 
coming out of an outermost loop at 170 NEXT C. 

Could the system have thought it was coming out of 
one of the earlier loops? The FOR statement correspond- 
ing to 170 NEXT C is 150 FOR C = R + 1 TO N. But there 
are two earlier FOR loops that use C, one starting at 50 
and the other starting at 80. Could this be the source of 
the confusion? 

If so, it was probably the loop starting at 80 that 
caused the problem. The loop starting at 50 is completely 
self-contained, but the loop starting at 80 has an abnor- 
mal exit: 90 IF T(C) = THEN 130. Here is our hypothe- 



188 January 1981 © BYTE Publications Inc 



From Digital Research 




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BYTE January 1981 189 



Languages Forum. 



Listing 2: Test runs of the program in listing 1. Test IV and Test VI can each return two sets of behavior, one for versions of BASIC 
that correctly execute the program and one for versions of BASIC that do not. 



]RUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

?6 

71 

?8 

?10 

?12 

ZERO IS NOT PRESENT 

NO DUPLICATIONS 

JRUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

?4 

?7 

?2 

?4 

?10 

ZERO IS NOT PRESENT 

T(1) = T(4) 

JRUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

?3 

?7 

?9 

?23 

?9 

ZERO IS NOT PRESENT 

T(3) = T(5) 

> RUN 
HOW MANY NUMBERS? 
?5 

INPUT 5 NUMBERS 
?4 
?0 
71 
?12 
?6 

ZERO IS PRESENT 
NO DUPLICATIONS 



Test I 



Test II 



Test III 



Test IV (correct) 



]RUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

?2 

?6 

?8 

71 

?0 

ZERO IS PRESENT 

T(D=T(4) 

RUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

71 

?0 

?24 

?1 

?24 

ZERO IS PRESENT 

T(3) = T(5) 

]RUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

?4 

?0 

71 

?12 

?6 

ZERO IS PRESENT 

?NEXT WITHOUT FOR ERROR IN 180 

]RUN 

HOW MANY NUMBERS? 

?5 

INPUT 5 NUMBERS 

71 

?0 

?24 

?1 

?24 

ZERO IS PRESENT 

?NEXT WITHOUT FOR ERROR IN 180 



Test V 



Test VI (correct) 



Test IV (erroneous) 



Test VI (erroneous) 



sis: when this abnormal exit was taken, the system did 
not realize that it was not in a loop any more. Then, 
when it came to 170, it thought that it was finally coming 
out of the loop that started at 80. Since this loop was an 
outermost loop, the system thought that it was no longer 
in any loops at all. Under these conditions (if they ex- 
isted), a NEXT statement, such as the one at 180, would 
truly be an error. 

This hypothesis is certainly plausible, but it has to be 
checked. Specifically, does it account for the fact that 
Tests I and III worked, while Tests IV and VI did not7 In 
Tests I and III, we print ZERO IS NOT PRESENT. This 
was done at 110, and it is not too hard to see that in this 
case the abnormal exit is not taken; we never jump from 
90 to 130. In Tests IV and VI, we print ZERO IS PRE- 
SENT, and under those conditions we do jump from 90 to 
130. This behavior is consistent with our hypothesis. 

Why did Test V work? The message T(1)=T(4) is 
printed by Test V. Looking at statement 210, we can see 



that we must have had R = l. Looking at statement 140, 
we can see that we must have been in the first iteration of 
that loop (since R = l) and that we made an abnormal exit 
from 160 to 210. Thus 180 was never executed. Again this 
behavior is consistent with our hypothesis. 

What happens if we change C to D in the earlier loop? 
If we go back to statements 80, 90, and 100, and change C 
to D throughout these statements, the bug disappears. If 
we change C to D throughout the loop at statements 50, 
60, and 70 (and leave 80, 90, and 100 without change), 
the bug does not disappear. This tells us two things. First, 
the bug has nothing to do with the loop at 50, 60, and 70 
(again consistent with our hypothesis). Second, the bug 
definitely does have something to do with variable 
names. The confusion is between FOR C at 80 and FOR C 
at 150, and the confusion goes away if one of these is 
changed to FOR D and if other corresponding changes 
are made. 

What happens if we change the earlier loop so that 



190 January 1981 © BYTE Publications Inc 



Computer experts 
(the pros) usually have big 
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That's why when they shop 
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micros, they look for 
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DATA INTEGRITY: FILE & 
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The biggest challenge 
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Languages Forum. 



System 




Bug? 


Alpha Micro (interpreter) 




no 


Alpha Micro (compiler) 




no 


APPLE (Integer BASIC) 




no 


APPLE (Applesoft BASIC) 




yes 


Archives (MBASIC) 




yes 


Atari 800 and 400 




yes 


Commodore PET 




yes 


Cromemco 




no 


Heath H-11A 




no 


Hewlett-Packard HP-85 




no 


IMSAI VDP-80 




no 


North Star Horizon 




no 


Ohio Scientific Challenger 1P 




yes 


Radio Shack TRS-80 Model I (Level 


BASIC) 


no 


Radio Shack TRS-80 Model I (Level II BASIC) 


yes 


Radio Shack Model II 




no 


Texas Instruments 99/4 




no 


Vector Graphics (MBASIC 5) 




no 


Table 1: A list of computer systems' running 


versions of 


BASIC that do and do not run corre 


ctly due to a 


bug in their 


handling of the FOR... NEXT loop. 


The system' 


■ listed here 


were tested on November 12 and li 


1, 1980. 





there is no FOR statement? This can be done by simply 
changing 80 to C = l and then replacing 100 by two 
statements: 100 C = C + 1 and 105 IF C < = N THEN 90. If 
this is done, even though the same variable name C is still 
used in two places, the bug disappears. This is further 
evidence for our hypothesis, because now there is no con- 
fusion about which FOR statement corresponds to the 
NEXT statement where the bug appears. 

The above changes illustrate ways of working around 
the bug. If you have a FOR loop with an abnormal exit, 
you will never find the bug if that particular FOR loop 
has a uniquely named loop-index variable. That is, if it 
ends with NEXT a, then nowhere else in the program 
should there be a statement NEXT a with the same a. 

Now let us dig a little deeper. At statement 90, the exit 
goes to 130, while the loop involves only statements 80, 
90, and 100. Why can't some of our BASIC systems tell 
that the exit at 90 is an abnormal exit? Presumably 
because they have no information whatsoever as to 
where loops start and end. Why would this be the case7 
There is a plausible explanation having to do with the 
relationship between the BASIC interpreter and its 
editor. 

Many of the BASIC systems that exhibit the bug have a 
very close coupling between running and editing a BASIC 
program. The two activities, in fact, can be carried on 
alternately with very little internal data processing to ac- 
company the switch-over from running to editing or from 
editing to running. Simple editing, however, may pro- 
duce far-reaching changes in the loop structure of a pro- 
gram. Adding or deleting a single FOR or NEXT state- 
ment can cause the pairing of other FOR and NEXT state- 
ments to be changed, even though they are widely 
separated from the added or deleted statement. There- 
fore, the decision must have been made not to keep 
FOR... NEXT pairing information at run time, with the 
hope that it would never really be needed. As we can see, 
Murphy's law is applied in this case with a vengeance. 

Let us now examine the bug technically in terms of 
stacking considerations. This will also suggest methods of 
fixing the bug. 



194 January 1981 © BYTE Publications Inc 




AH JH| ^P Licenced by Sinclair Research Ltd. 

Microcomputer 

for everyone at 
a Micro Price 



The LMicrofkeJ 



The unique 

and valuable 

components of the MicroAce 

The MicroAce is not jusl another personal 
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• Timer under program control. 




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'Excellent value' indeed! 

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Yet the MicroAce really is a complete, powerful, 
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The MicroAce is programmed in BASIC, and you 
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The MicroAce is pleasantly straightforward to 
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per Dollar! 

The MicroAce owes its remarkable low price to its 
remarkable design: the whole system is packed on 
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chips. A single SUPER ROM, for instance, contains 
the BASIC interpreter, the character set, operating 
system, and monitor. And the MicroAce 1K byte 



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miniature computers 

A COMPLETE COMPUTER 
for $149.00 for 1K Kit 

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RAM (expandable to 2K on board) is roughly 
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The display shows 32 characters by 24 lines. 

And Benchmark tests show that the MicroAce is 
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No other personal computer offers this unique 
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The MicroAce teach-yourself 
BASIC manual. 

If the features of the BASIC interpreter mean 
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represents a complete course in BASIC 
programming from first principles to complex 
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refunded if you buy a MicroAce later.) 
A hardware manual is also included with every kit. 

The MicroAce Kit: 

$149.00 with IK COMPLETE 

$169.00 with 2K 

Demand for the MicroAce is very high: use the 
coupon to order today for the earliest possible 
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rotation. If you are unsuccessful in constructing 
your kit, we will repair it for a fee of $20.00, post and 
packing FREE. Of course, you may return your 
MicroAce as received within 14 days for a full 
refund. We want you to be satisfied beyond all 
doubt and we have no doubt that you will be. 



Z80 A microprocessor 

chip, widely recognised 

iis the besi ever made. 




Your MicroAce kit 
contains... 

• Printed circuit board, with 
IC sockets for all ICs. 

• Complete components set, 
including all ICs all 
manufactured by selected 
world-leading suppliers. 
New rugged keyboard, 
touch-sensitive, wipe-clean. 
Ready-moulded case. 
Leads and plugs for 
connection to domestic TV 
and cassette recorder. 
(Programs can be SAVEd 
and LOADed on to a 
portable cassette recorder.) 
Mains adaptor of 600 mA 
at 9VDC nominal 
unregulated. 
FREE course in BASIC 
programming and user 
manual. 



JOIN THE REVOLUTION - DON'T GET LEFT 
BEHIND - ORDER YOUR MICROACE NOW!! 



Send Check, Money Order or quote your Credit Card No. to: 
MicroAce 1348 East Edinger, Santa Ana, California, Zip Code 92705. 
or phone (714) 547 2526 quoting your Credit Card Number. 



Quantity 



Description 



TOTAL 





MicroAce Kit IK 


$149.00 






MicroAce Kit 2K 


$169.00 






Manual 


$10.00 






1K Upgrade Kit 


$29.00 




Shipmen 
add 6% 


ts inside California 
TAX 


TOTAL 





Amex. 
Diners 
Check 

Money Order 
Master Charge 
Visa 



Card No.. 



Exp. Date_ 



■■■ «■■ 



Address- 
City 



.Zip. 



Circle 121 on inquiry card. 



BYTE January 1981 195 



6809 

SOFTWARE 

POWER TOOLS 



BY MICROWARE" 



OS-9 ™ MULTIPROGRAMMING 
OPERATING SYSTEM 

j\ true multitasking, real time operating system for 
J M timesharing, software development, database, 
X JL process control, and other general applications. 
This versatile OS runs on almost any 6809-based computer. 

■ UNIX™ -like file system with hierarchical directories, 
byte-addressable random-access files, and full file security. 
Versatile, easy-to-use input/output system is hardware in- 
dependent and expandable. 

■ Powerful "shell" command interpreter features: I/O 
redirection, multiple job stream processing, and more. In- 
cludes a complete set of utility commands. 

■ OS-9 Level Two uses hardware memory management 
and can address over one megabyte of memory. Also 
includes pipes and filters for inter-process data transfers. 

■ OS-9 Level One runs on systems without memory 
management hardware having up to 56K memory. 

□ OS-9 Level Two $495* □ Level One $150' 

BASIC09™ PROGRAMMING 
LANGUAGE SYSTEM 

Extended BASIC language compiler/interpreter with 
integrated text editor and debug package. Runs 
standard BASIC programs or minimally-modified 
PASCAL programs. 

■ Permits multiple named program modules having local 
variables and identifiers. Modules are reentrant, position 
independent and ROMable. 

■ Additional control statements for structured 
programming: IF . . . THEN . . . ELSE, FOR . . . NEXT, 
REPEAT . . . UNTIL, WHILE ... DO, LOOP . . . ENDLOOP, 
EXITIF . . . ENDEXIT. 

■ Allows user-defined data types and complex data 
structures. Five built-in data types: byte, integer, 

9 digit floating-point, string and boolean. 

■ Runs under OS-9'" Level One or Level Two. D$195* 

OTHER OS-9™ FAMILY SOFTWARE 

■ Microsoft BASIC ■ Interactive Assembler 

■ Macro Text Editor ■ Interactive Debugger 

■ Stylograph™ Screen-Oriented Word Processor 

BASIC09 is a trademark of Motorola, OS-9 is a trademark of Motorola and 
Microware'" . UNIX is a trademark of Bell Laboratories. * Most software is 
available on ROM, diskette and tape in versions for many popular 6809 
computers. Contact Microware® for specific availability. 




MICROWARG® 

Microware Systems Corp., Dept. B2 

5835 Grand Avenue, Des Moines, Iowa 50304 

(515) 279-8844 



Languages Forum. 



At the start of a FOR loop, certain information is 
stacked; upon normal exit from that loop, it is unstacked. 
Upon abnormal exit from a loop, the information is also 
supposed to be unstacked, but in most cases it does not 
matter whether the information is unstacked or not. In 
this case, however, it appears to matter. The sequence of 
events is as follows: 

• At statement 50, we enter a loop, and C is stacked. 
Clearly, the loop-index-variable name must be stacked, 
along with other information that we shall ignore for the 
moment. 

• At statement 70, we make a normal loop exit, and C is 
unstacked, leaving the stack empty. 

• At statement 80, we enter another loop, and C is 
stacked again. 

• At statement 90, if we make the abnormal exit from this 
loop, C is supposed to be unstacked; but let us assume for 
the moment that it is not. 

• At statement 140, we enter another loop, and R is 
stacked. 

• At statement 150, we enter a third loop, and C is again 
stacked. Note that we are now in two loops, although the 
system thinks that we are in three. 

• At statement 170, we exit from a loop, and C is 
unstacked. But C is on the stack twice. Which version of 
C is unstacked? It must be the one at the bottom of the 
stack, because, according to our analysis, when we get to 
statement 180, the stack is empty. Then we try to unstack 
an entry, and, since it is empty, we signal an error. 

This gives a clue to fixing the bug in an imaginative 
way. Of course, one way of fixing the bug is to simply 
keep the relevant FOR... NEXT pairing operation around 
at run time. But a simple change in the handling of NEXT 
statements would also fix the bug in this case. We must 
search the stack for the right information to unstack, and 
the trick is to search the stack downwards from the top, 
rather than upwards from the bottom. If we had done 
this, we would have unstacked the right version of C, and 
the bug would not have occurred. 

Are there any other ill effects from leaving extra infor- 
mation on the stack that should be unstacked, as is done 
by those systems that have the bug? At the end of the ex- 
ecution of the program, the stack will not be empty. 
Since this could also happen if there were a FOR state- 
ment in the program without a corresponding NEXT, this 
indication might be given (erroneously) at the end of the 
run. (The Data General D2 microcomputer system ap- 
pears to exhibit this behavior.) Another possible un- 
wanted effect is unlimited stack growth, causing stack 
overflow. If an abnormal exit causing extraneous stack 
information is inside an outer loop, then unwanted stack 
information can continue to pile up — eventually resulting 
in overflow. This situation is more serious on a 
Z80-based system than on a 6502-based system, since the 
stack on the 6502 is confined to hexadecimal addresses 
0100 thru 01FF, and it wraps around when it overflows. 

In conclusion, let it be carefully noted — as is necessary 
in this fast-changing field— that all the information in this 
article is as of November 12 and 13, 1980. ■ 



196 January 1981 © BYTE Publications Inc 



Circle 122 on inquiry card. 



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R.S. 90 Day Limited Warranty 
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Largest Inventory 
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Circle 123 on Inquiry card. 



BYTE January 1981 197 



WE SUPPORT THE BUS OF THE FUTURE: 

S-100 systems are ideal for high level industrial, commercial, and scientific applications. 

Modularity prevents obsolescence; conformance to the IEEE 696/S-100 standards assures well- integrated system performance. 

Find out what a computer can really do . . . specify CompuPro and the S-100 bus. 



NEW: "SYSTEM SUPPORT 1" 
S-100 MULTIFUNCTION BOARD 
$295unkit, $395 assm, $495 CSC 

Finally — one multi-purpose board combines all the most useful system 
support funclions required by your computer. Extensive use of LSI 
technology not only packs the greatest number of features in the minimum 
amount of space, but also increases reliability and cuts costs compared lo 
buying numerous single-function boards. Features include: 

— Sockets for 4K of extended address EPROM or RAM (271G pinoul) 

— Crystal controlled month/day/year/lime clock 

— Optional high speed math processor (951 1 or 9512) 

— Full KS-232 serial port 

— Three 16 bit interval timers (cascade or use independently) 

— 15 levels of vectored interrupts 

— Conforms fully to all IEEE 696/S-100 standards 

Ready to add some extra performance to your S-100 system? Then this is 
the board for you. System Support 1 comes with a comprehensive owner's 
manual that includes numerous software examples; add $195 to Ihe above 
prices for the optional 9512 math processor. 

COMPUPRO S-100 MOTHERBOARDS: 

DESIGNED FOR THE FUTURE, 

AVAILABLE NOW 

Fully terminated and fully shielded, these advanced motherboards handle 
the coming generation of 5 to 10 MHz CPUs as well as present day 2 and 4 
MHz systems. Mechanically compatible with most computer enclosures. 
Unkits have edge connectors and termination resistors pre-soldered in plane 
for easy assembly. 

20 slot motherboard with edge connectors — unkit $174, assm $214 
12 slot motherboard with edge connectors — unkit $129, assm $169 
6 slot motherboard with edge connectors — unkit $89, assm $129 

CPU Z: 8 BITS OF Z80* 
POWER FOR THE S-100 BUS 

Like many others, we claim full conformance lo IEEE 696/S-100 specifica- 
tions; unlike many others, we'll send you the timing specs to prove it. CPU Z 
includes all standard Z-80A* features along with power on jump, on- 
board fully maskable interrupts for inlerrupl-driven systems, selectable 
automatic wait stale insertion, provision Tor adding up to 8K of on-board 
EPROM, and 16/24 bit extended addressing. Works with 6 Mil/. CPUs; sup- 
plied with 4 MHz CPU. $225 unkit, S295 assm, $395 CSC. 

8088/8086 MONITOR-DEBUGGER: $35 

Supplied on single sided, single density, soft-sector 8" disc. CP/M* com- 
patible. Great development tool: mnemonics used in debug conform as closely 
as possible to current CP/M* DDT mnemonics. 

COMPUPRO COMPUTER ENCLOSURE 
$289 desktop, $329 rack mount 

This enclosure does justice to the finest computer systems. Includes dual 
AC outlets and Tuseholder on rear, heavy-duty line filter, quiet ventilation 
fan, and black anodized front panel (with textured vinyl painted cover for 
desktop version). Pro-drilled base accepts our high-performance S-100 
motherboards or types by Vector, California Digital, and others. Rack mount 
version includes slides for easy pull-out from rack for maintenance or board 
changing. 

PASCAL/M* FROM SORCIM: $175 

PASCAL — easy lo learn, easy to apply — can give a microcomputer with 
CP/M* more power than many minis. We supply a totally standard Wirth 
PASCAL/M* 8" diskette and comprehensive manual. Specify Z-80* or 
8080/8085 version. 



CompuPro products nrt: available in unkit form, assembled, or qualified undor the high- ■ 
J reliability Certified Sysli;m Component (CSC] [mi^nim (200 hour burn-in. oxlmisivo testing, ! 
I extended 2 yonr warranty, moro), Please note lhal unkils are not inlendud for novices, as j 
I de-bugging may bo roquirod duo lo problems such as IC infant mortality, factory sorvioo isj 
I available for unkits tit u fhii Bervice Charge ' 

I _____ ______! 

LOWEST PRICE EVER !! 
16K DYNAMIC RAMS — 8i$37 

lust what you would expect from the memory leader: the lowest price 
ever on 16K dynamic RAMs, backed up with a 1 year warranty. These are 
lop quality, low power, high speed (200 ns) parts that expand memory in 
TRS-80* -I and -II computers as well as machines made by Apple. Exidy, 
Heath H89. newer PETs, etc. Add $3 for two dip shunts plus TRS-80* con- 
version instructions. Hurry! 16K dynamic RAM prices may never be this low 
again, and quantities are limited. 

CPU 8085/88: 16 BIT DUAL PROCESSING 
POWER FOR THE S-100 BUS 

When we shipped Ihe first CPU 8085/88 board back in June of 1980. we 
created ;i bridge between the 8 bit world of the present and Ihe 16 bit world 
of the future. By using an 8088 CPU (for 16 bit power with a standard 8 bit 
bus) in conjunction with an 8 bit 8085. CPU 8085/88 is downward compatible; 
with 8080/8085 software, upward compatible with 8086/88 software (as well 
as Intel's coming P-Series), designed for professional-level high speed ap- 
plications, and capable of accessing 16 megabytes of memory . . . while con- 
forming fully to all IEEE 696/S-100 standards (timing specs available on re- 
quest). 

booking for a powerful 8 bit CPU board? Looking for a powerful 16 bit 
CPU board? Then look at CPU 8085/88, the best of both worlds. 

Prices: $295 unkit, $425 assm (both operate at 5 MHz); $525 CSC (with 5 
MHz 8085. 6 MHz 8088). Owner's manual available separately for $5. 

Also available: CPU 8085 (single 8 bit processor version of above) Tor $235 
unkit, $325 assm, $425 CSC. 

2102 MEMORY SPECIAL 

While they last 99 cents each. 10/$9.90. Low power. 

CLOSEOUT SPECIAL: 32K fully static memory for the SBC bus 
(RAM XI), now only $699 assembled. Limited quantities. 

OTHER S-100 BUS PRODUCTS 

Active Terminator Board $34.50 kit 

Memory Manager Board $59 unkit, $85 assm, $100 CSC 

Mullen Extender Board $59 kit 

Mullen Relay/Opto-Isolator Control Board. .$129 kit, $179 assm 

Spectrum color graphics board $299 unkit, $399 assm, $449 CSC 

2708 EPROM Board (2708s not included). . .$85 unkit, $135 assm, $195 CSC 

Interfacer 1 (dual RS-232 serial ports) $199 unkit, $249 assm, $324 CSC 

Interfacer 2 (3 parallel + 1 serial port) $199 unkit, $249 assm, $324 CSC 

COMING SOON: "MPX 1", a front end processor/system 
multiplexer for high speed multi-task/multiuser setups. Greatly 
enhances multiuser performance by taking over system I/O 
overhead from the main CPU. Included on board: 5 MHz 8085 
microprocessor, 2K of ROM, 4K of RAM, interrupt controller, and 
much more. Finally . . . multi-processing is an affordable reality. 
Also, if you've been waiting for someone to do a dual density 
disk controller board right . . . your patience has been rewarded. 
The CompuPro disk controller is on its way. 

TERMS! till rim mill lux. Allow m lensl .v.. shipping oxnotil, 1-nHiniltxl. Ontors onilorsl5 ntld S3 hlMUUing. VISA' 
/Mnsloroortl" onlors |S25 rain] Will [4181 5fi2-Hli:ili. 24 hrs. 1'Iiiomi; inolmlo slrool mhlrrss for UTS dalivory. Ppfeua 
itnl suli|ool lo i:lmiii!0 wlltl'llll rojllfit). 

FREE CATALOG: find mil more about the CompuPro product linn, and bow il can turn your 
computer into a powerful Information processing tool, l-or 1st dnss delivery, add 41 oonts 

in slumps: Fnrnijpi orders unit $2 (rnfundobli: with order). 

LEGAL CORNER: KHUA Ikii ,.-ui-I.T-->1 1r.ul.-ni.irk >il Zihi W ; I KSIIII i. .1 lr.nl. nurL ,.l Hoi I. unit Ifcrnifl I'ASIIAI.M w .1 IMiliKiori ..I >,,.n im. i:i- M r» 



COMPUPRO PRODUCTS ARE AVAILABLE AT FINER COMPUTER STORES WORLD-WIDE 

OR DIRECT FROM THE FACTORY. 



CompuPro 

OAKLAND AIRPORT, CA 94614 



from pt50S®ll(£ 

v ^ ELECTRONICS ^ 



198 BYTE January 1981 



Circle 125 on inquiry card. 




Memory has assumed tremendous importance in today's 
computers, which is why you don't just need memory: you 
need reliable, finely-tuned, precision machines. 

We've understood the importance of memory since we 
introduced our first memory board well over 5 years ago. 
That's why CompuPro memory conforms fully to all IEEE 
696/S-100 specifications . . . uses low power static 
technology to avoid dynamic timing problems . . . comes in a 
choice of formats (unkit, assembled , or qualified 
under the Certified System Component high- 
reliability program) . . . and zips along to keep your 
throughput up where it should be (10 MHz 
operation with CSC and assembled boards, 5 MHz 
with unkit boards). We back these precision 
machines with a standard 1 year warranty, and 2 
year extended warranty for CSC boards. 



RAM memory machines from 
CompuPro couple experience, 

innovative engineering, and 

cost-effectiveness. 

See them in person at finer 
computer stores world-wide. 



CompuPro 

OAKLAND AIRPORT, CA 94614 



from 

iijl®lB6) 



W* ELECTRONICS ^ 



Prices (assembled and tested units]: 8K RAM 2A, 
$189; 16K RAM 14*, $349; 16K RAM 20-16**, 
$399; 24K RAM 20-24**, $539; 32K RAM 20-32** 
$699. Write for prices on unkits and CSC 
boards. 128K RAM 21-128* (CSC only), $2795. 
Also available in 64K and 96K configurations. 
For 24 hour VISA* /Mastercard® orders, 
call (415) 562-0636. 



•With IEEE extended addressing 

**Uso with IEEE ox tended addressing systems o 



BYTELINES 



News and Speculation About Personal Computing 

Conducted by Sol Libes 



*» upercond uctlvl ty At 
Room Temperatures 
Reported: A breakthrough 
for the next generation of 
supercomputers may have 
been made. It was previous- 
ly thought that superfast 
computers, using Josephson 
junctions, would require 
supercooling to a tempera- 
ture near absolute zero. 
Now, Fred W Vahldiek of the 
Wright-Patterson Air Force 
Base, Dayton, Ohio reports 
that he has achieved super- 
conductivity at room tem- 
peratures. Vahldiek has 
developed titanium borite 
crystals with zero resistance. 
Further research will be 
required to determine 
whether or not this could 
lead to the development of 
computers with picosecond 
machine cycles and 100% 
power efficiency. 



I 



BM Announces 370- 
On-A-Chlp: IBM has dis- 
closed what many already 
suspected: it has implement- 
ed the circuitry of a model 
370 processor on a single in- 
tegrated circuit. IBM has 
created a 370 model 1 38 pro- 
cessor that utilizes 5000 cir- 
cuits and Schottky-clamped 
bipolar TTL (transistor-tran- 
sistor logic) technology that 
can execute 2000 instruc- 
tions per second. The device 
has a cycle time of only 100 
ns and consumes 2.3 watts. 
It is part of a research pro- 
ject, and no specific plans 
for a product have been an- 
nounced. 

I™ ight For 16-Bit Micro- 
processor Market: It ap- 
pears that the 16-bit micro- 
processor market is the 
scene of a three-way battle 
between the Motorola 
68000, the Zilog Z8000, and 
the Intel 8086. Although the 
68000 is ranked first in per- 
formance and the 8086 is 
ranked last, the volume of 
sales is greater for the 8086. 
Intel has a two-year lead in 



product availability. This 
means that there is already a 
substantial software base 
and peripheral device sup- 
port. Furthermore, Intel has 
introduced 8086 enhance- 
ments such as a 10 MHz ver- 
sion, an arithmetic co-pro- 
cessor, and a new 32-bit mi- 
croprocessor, the iAPX-432, 
that may undercut the 68000 
and Z8000. Intel expects to 
start shipping samples of the 
iAPX-432 in two or three 
months. 



u, 



'NIX-LIke Operating 
Systems Increasing In 
Popularity: Several soft- 
ware suppliers are now offer- 
ing UNIX-like operating sys- 
tems that may rival CP/M. 
The first UNIX-like software 
package, called TYNIX, was 
released for LSI-11 and 
Heath H-11 systems in 1978 
by the Boston Children's 
Museum. In 1979, Yourdon 
announced OMNIX for Z80 
computers and advertised it 
as CP/M compatible and 
similar to UNIX. Yourdon 
then withdrew it because of 
software bugs, but it may be 
released again. Whitesmiths 
released its IDRIS system in 
early 1980. Also in 1980, 
ElectroLabs introduced its 
OS-1 UNIX-like system (now 
marketed by Software Labs), 
and late last year Microsoft 
and Morrow Designs an- 
nounced packages for Z8000 
and Z80 systems, respective- 

ly. 

^■opyrlght Decision 
Overturned: In Chicago, 
the US Court of Appeals has 
overturned an earlier ruling 
that ROM- (read-only mem- 
ory) based software cannot 
be copyrighted. In the case 
of Datacash vs JS & A (as 
reported earlier in this col- 
umn), the court had ruled 
that the marketing of a chess 
game by JS & A with a pro- 
gram identical to the one 
originally developed by 



Datacash was not copyright 
infringement because under 
the 1909 copyright law the 
program could not be read 
with the naked eye. 



E thernet Specifica- 
tions Released: Xerox, 
Digital Equipment, and Intel 
have published specifica- 
tions for the Ethernet system 
developed by Xerox. Ether- 
net provides a local net- 
working system for word and 
data processing applica- 
tions. Xerox has already 
released some Ethernet 
products. 

Ethernet is a passive sys- 
tem and does not use switch- 
ing logic or a central com- 
puter. Rather, coaxial cable 
and communications trans- 
ceivers attach each machine 
to the network; each ma- 
chine is assigned a 48-bit ad- 
dress. Data is transferred in 
serial groups which include 
the data and the addresses 
of both the sender and the 
addressee. Each transceiver 
monitors the cable for data 
with its address. It is ex- 
pected that the IEEE (In- 
stitute of Electrical and Elec- 
tronics Engineers) will in- 
tegrate the Ethernet specifi- 
cations into the networking 
standard currently in devel- 
opment. 

Amda Language Final- 
ized And The Rush Is 

On: Ada, the language that 
the DOD (Department of 
Defense) expects to even- 
tually replace all other 
languages, has been final- 
ized, according to Jean Ich- 
biah, president of Apsys, 
Washington DC. Over nine 
hundred revision proposals 
were submitted, and several 
major improvements have 
been incorporated into the 
proposed Ada language 
standard that was released 
in 1979. The most significant 
improvement is the addition 
of tasking. The Ada Refer- 



ence Manual may be obtain- 
ed from the DOD's DARPA 
office, 1400 Wilson Blvd, 
Arlington VA 22209. 

At least twenty-five com- 
panies and universities are 
reported to be in the process 
of developing compilers for 
the Ada language. A few uni- 
versities have already had 
their Ada compilers running. 
However, the first commer- 
cial release has yet to occur, 
Intel claims that its new 
32-bit microprocessor, due 
for release shortly, will use 
Ada as its primary language. 
WD (Western Digital) is 
rumored to be working on a 
single-board Ada computer 
that is similar to its Pascal 
MicroEngine. WD has pur- 
chased a 20% interest in 
Telesoftware Inc of San 
Diego, which is developing 
an Ada compiler. (Dr Ken- 
neth Bowles of UCSD Pascal 
fame owns an additional 
40% interest in the com- 
pany.) Reportedly, Telesoft- 
ware already has a prelimin- 
ary version of its Ada com- 
piler running. 



WP/M For 8086/8088 
Systems Released: Digital 
Research has released CP/ 
M-86. This operating system 
is designed for 8086- and 
8088-based systems and pro- 
vides the same facilities and 
file format as CP/M, release 
2. CP/M-86 can also function 
as a slave node in a CP/NET 
network. As with 8080-based 
versions of CP/M, the logic- 
and hardware-dependent 
portions of CP/M-86 are 
modularized for ease of cus- 
tomization. Digital Research 
also plans to release MP/M 
and PL/I for 8086/8088-based 
systems in the near future. 



I ontgomery Ward 
And Sears Expand Per- 
sonal Computer Market- 
ing: After test marketing 
Ohio Scientific computers in 
selected stores, Montgom- 



200 January 1981 © BYTE Publications Inc 




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Report Writer 

is a trademark of Carolina Business Computers 

Selector IV Is a trademark of Micro-Ap Pearl is o 

trademark of CPU International Pascal/M, ACT & TRANS 86 are 

trademarks of Sorcim CBASIC2 is a trademark of Compiler Systems 

Magic Wand is a trademark of Small Business Applications Textwiter, Datebook & 

Milestone are trademarks of Organic Software Ultrasort-ll is a trademark of Computer Control Systems 



For shipping add S5 



Circle 126 on inquiry card. 



Magic Menu is o trademark of Charles Merrift Copywriter is a trademark of Systronics Mlcrostat is a trademark of Ecosoft 
S-Basic is a trademark of Topaz Programming CP/M & MP/M are trademarks of Digital Research TRS-80 is a trademark of Tandy 
Superbrain is a trademark of Intertec Data Systems UCSD Pascal is a trademark of the Regents of the University of California 
in US- S10 outside US per package California residents add appropriate state sales tax Terms: Prepaid check, M/C or VISA 

or in US COD (UPS) Dealer inquiries invited Prices effective until March 1, 1981 

BYTE January 1981 201 



BYTELINES 



ery Ward has decided to ex- 
pand its personal computer 
sales into one hundred 
stores. The stores will sell 
the OSI Challenger 1P and 
4P cassette-based systems 
with accessories such as disk 
drives, video monitors, print- 
ers, security systems, and 
software. Sears is now carry- 
ing two full pages in its 
catalog promoting the Atari 
400 and 800 computers, 
games software packs, and 
peripherals. Other retail 
chains and department 
stores are expected to follow 
in their footsteps. 

Jystem Puts Local Net- 
work On Cable TV: Sytek 
Inc, Sunnyvale, California 
has introduced a packet- 
network system to support 
up to 24,000 terminals and 
operate at up to 9600 bps 
(bits per second) over a 
cable TV system. This sys- 
tem, called "LocalNet," is 
expected to fill the gap that 
exists between such systems 
as Ethernet and ARPANET. 
Ethernet is limited to a 1 to 2 
km distance while ARPANET 
is committed to long-dis- 
tance distributed processing. 
LocalNet can cover up to 50 
km distances on a single 
coaxial cable and can be 
piggybacked onto existing 
CATV cable systems, thus 
providing a very low-cost 
networking system. 



IM, 



I EC Claims Cure For 
Dual-Sided Floppy Prob- 
lems: NEC, the Japanese 
manufacturer, claims to 
have developed a floppy 
disk system which elimi- 
nates the disk and head wear 
problems associated with 
dual-sided floppy disks. NEC 
uses an "air" shock absorber 
to cushion the force of the 
heads landing on the disk, 
and the company claims 
that its new FD1160 Soft 
Touch drive provides twice 
the media and head life of 
competitive drives. 

Standard For 32-Blt 
Bus: The IEEE has formed a 
committee to draft a back- 
plane bus standard, desig- 



nated as P896, for 32-bit 
microcomputers. According 
to committee chairman An- 
drew Wilson, P896 is already 
well along in development, 
and a draft may be released 
soon. The bus will support 
32-bit microprocessors un- 
der development by Intel 
and other companies. It will 
be processor-independent 
and will support up to sixty- 
four bus masters and clock 
rates of up to 20 MHz. 

fcSOOO Call Conven- 
tions Proposed: Micro- 
soft, Bellevue, Washington 
(the largest supplier of mi- 
crocomputer software) has 
proposed a standard for 
Z8000 calls that specify 
parameter-passing and regis- 
ter usage. Adoption of a 
standard would enable 
Z8000 languages, applica- 
tion programs, and operat- 
ing systems to be more easi- 
ly interfaced, and would fa- 
cilitate the building of a 
Z8000 program library simi- 
lar to the present CP/M User 
Group Library. 

mJ o Computers Cause 
Unemployment? Calvin C 
Cotlieb, a professor of Com- 
puter Science at the Univer- 
sity of Toronto, delivered a 
paper at the recent IFIPS (In- 
ternational Federation of In- 
formation Processing Soci- 
eties, Inc) Congress-80 which 
claimed that computers are 
causing unemployment. 
Gotlieb cited dozens of stud- 
ies to support his claim; for 
example, at one Western 
Electric facility, the number 
of employees was reduced 
by 50% (from 39,200 to 
19,000) over a six-year peri- 
od, while production doub- 
led. A Japanese TV manu- 
facturer increased produc- 
tion by 25% over a four-year 
period, while reducing the 
number of workers by 50%. 
Cotlieb contends that com- 
puters must be used more 
wisely, and cited a West Ger- 
man study that stated: 
"(C)omputers make things 
more formal, more routine, 
more bureaucratic and inev- 
itably lead to less humane 
treatment of people." He 



also cited a law on the West 
German books that com- 
plains: "(O)nce a decision is 
made by a computer, no one 
is permitted to challenge it," 

Atmateur Robotics On 
The Rise: More and more 
hobbyists are building their 
own robots. The evidence is 
the fact that there are al- 
ready several companies 
supplying robot parts to hob- 
byists and two magazines 
catering to their interests. 
Hobbyists seeking parts and 
kits should write to: Hobby 
Robotics Company, POB 
997, Liburn CA 30247, and 
the Robot Mart, 19 W 34th 
St, New York NY 10001. 
Robot Mart also publishes 
the Hobby Robot Newslet- 
ter. 

■ lat-Panel Display 
Technology Improving: 

Although CRTs (cathode-ray 
tubes) still dominate the 
computer-terminal display 
field, it appears that several 
flat-screen systems will soon 
be ready to challenge that 
dominance. The new tech- 
nologies include electro- 
phoretic, electrochromic, 
LCD (liquid-crystal display) 
and LED (light-emitting 
diode) systems. LCD panels 
are already available in 
1-and 2-line versions. Several 
firms will soon offer multi- 
line panels. Dot-matrix dis- 
plays are also under devel- 
opment by several firms, 
and prototypes are becom- 
ing available in LED, vacu- 
um fluorescent, and elec- 
troluminescent technolo- 
gies. There is no doubt that 
flat-screen terminals will 
compete with small CRTs 
within two or three years. 

One manufacturer of flat 
screens is Optotek Ltd, of 
Ottawa, Canada, which will 
soon offer a display using 
LEDs that are 1/8000 inch in 
diameter. Each square inch 
of the display has 4000 
diodes. A 3- by 4-inch display 
has 49,000 diodes. Control of 
the diodes is performed by 
special VLSI (very large- 
scale integration) integrated 
circuits provided for each 
square-inch block. 



R 



andom Bits: As of 

January 1, 1981, Radio 
Shack has stopped produc- 
tion of the TRS-80 Model I 
computer, in anticipation of 
increased sales of the 
TRS-80 Model III. .The IEEE 
has established a committee 
to develop a standard for 
benchmark programs for 
microprocessor users... 
Several hundred workers at 
the Minneapolis Star and 
Tribune newspaper recently 
went on strike tc protest, 
among other things, the 
newspaper's experimental 
electronic newspaper pro- 
ject with CompuServe Inc.... 
Japan's NTT (Nippon Tele- 
graph and Telephone Public 
Corporation) will soon in- 
augurate a public facimile 
network that may be the first 
step in developing an elec- 
tronic mail system. ...Intel 
has released prices on its 
new 2764 64-K-bit (16K by 8 
bits) 250ns EPROM: $163 
each in lots of one 
hundred. ...Seventy to eighty 
percent of all TRS-80 Model 
II systems are running CP/M; 
this statement is based on 
the fact that Lifeboat 
Associates has already sold 
4000 copies of CP/M for the 
Model II. 



R 



l andom Rumors: Ap- 
ple Computer Company may 
be setting up its own floppy- 
disk manufacturing opera- 
tion to make double-sided 
double-density drives for its 
new Apple III Computer. In- 
troduction of the drive is ex- 
pected by mid-year.... 
Sources say that Radio 
Shack is close to releasing a 
hard-disk drive for the 
TRS-80 Model II and III com- 
puters. Further, Radio Shack 
will soon release version 1.3 
of its DOS (disk-operating 
system) to replace version 
1.2 which, reportedly, has 
many bugs. Unfortunately, 
the two versions will not be 
compatible. ...Altos Com- 
puters is said to have switch- 
ed from the Z8000 to the 
8086 for its new 16-bit sys- 
tem. This decision was prob- 
ably due to the introduction 
of the CP/M^86 from Digital 



202 January 1981 © BYTE Publications Inc 



Suddenly, RCA makes talking to 
your computer a lot cheaper. 



New interactive data terminal 
with color graphics-only $36 




RCA's new VP-3301 is a professional quality, ASCII 
encoded, interactive data terminal, suitable for a wide 
variety of industrial, educational, business and individual 
applications requiring interactive communication 
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computer or to a standard modem for over the phone 
access to time sharing networks and data bases. And it's 
compatible with networks such as those provided by 
CompuServe Information Services and Source Tele- 
computing Corp. Microprocessor intelligence and LSI 
video control integrated circuits bring performance, 
features and flexibility at a low price. Power supply 
included. 

Unique color locking circuitry creates sharp, jitter 
free, true color graphics and rainbow free characters. 

Displays the entire field of characters in any of 8 
colors against any of 8 background colors (7 gray scales 
with monochrome monitors). Or to add special 
emphasis, you can display individual letters, words or 
lines in different colors or in reverse video. 

The VP-3301 offers you a choice of two software- 
selectable display formats: Either 40 characters by 24 
lines. Or 20 characters by 12 lines. 

The terminal's resident character set consists of 52 
upper and lower case alphabetics, 1 numerals, 32 
punctuation/math symbols, and 31 control characters. 



You can also define a total of 128 of your own characters. 
Including: Greek letters and other foreign alphabets, 
graphic symbols, large graphics building blocks.playing 
card suits, unique character fonts, and "little green men." 

The keyboard section features flexible-membrane 
key switches with contact life rated at greater than five 
million operations. A finger positioning overlay and 
positive keypress action give good operator "feel". 

An on-board sound generator and speaker provides 
aural feedback for key presses and may also be 
activated with escape sequences to provide an audio 
output. 

The sealed keyboard surface is spill proof and dust 
proof. This combined with high noise immunity CMOS 
circuitry makes the VP-3301 ideal for hostile 
environments. 

Output is industry standard asynchronous RS232C 
or 20 mA current loop with six switch selectable baud 
rates and 8 selectable data formats. 

The terminal can be connected directly to a 525 line 
color or monochrome monitor. Or to a standard TV set 
using an Rf modulator. 

For more information, contact RCA Microcomputer 
Marketing, New Holland Avenue, Lancaster, PA 17604. 

Or call our toll-free number: 800-233-0094. 



'Suggested user price. 



RC/1 



Circle 127 on inquiry card. 



BYTE January 1981 



203 



BYTELINES 

Research. ..North Star Com- 
puters might be developing 
a single-board 8088-based 
system that will work with a 
hard disk and support CP/M 
....Whitesmiths Ltd is ru- 
mored to be about to release 
an 8088/8086 version of its 
C compiler.... A California 
firm may be readying an 
under $300 OEM (original 
equipment manufacturer) 
daisywheel printer that 
would be set for introduc- 
tion by the end of the year. 

I redlctlons. Predic- 
tions.. .In my December 
1979 column I made eleven 
predictions for 1980. Several 
readers asked me to grade 
myself on how well I did, so 
here goes: 

1 . The first Japanese per- 
sonal computer system will 
become available in this 
country. Score a "correct." 
In fact, several have been in- 
troduced and reported on in 
this column. Look for many 
more in 1981. 

2. Competitive pressures on 
small manufacturers will in- 
crease. This will cause 
several mergers, consolida- 
tions or acquisitions. Score a 
"correct" on this one too. So 
many failures, mergers and 
acquisitions occurred that 
they are too numerous to be 
mentioned. More will be 
forthcoming in 1981. 

3. A sizable number of audio 
and office equipment re- 
tailers will enter the com- 
puter retailing business. This 
will create pressures on con- 
ventional computer stores. 
We may even see the ap- 
pearance of stores that sell 
only software, much like 
audio record stores. Score a 
"maybe." Although some 
steps have been taken in this 
direction (eg: Bell & Howell 
and several other audio/ 
visual and office equipment 
suppliers), the real first step 
has yet to be taken. ..possible 
developments this year or 
next. 

4. 16-bit microcomputer 
systems will be common- 
place. Score a "maybe" on 
this one too. Although 
several 16-bit systems were 
introduced, lack of 16-bit 



parts and software limited 
their adoption. We should 
see a significant increase in 
their acceptance in 1981 
with the availability of 
CP/M, MP/M, UNIX and 
other powerful operating 
systems. 

5. IBM, DEC, Data General, 

H-P and other minicomputer 
makers will introduce low- 
cost microcomputer systems. 
Score a "partial" on this one, 
as H-P (Hewlett-Packard) in- 
troduced the HP-85 and IBM 
showed its S-100 product in 
Europe but withheld it from 
the US market. These com- 
panies may jump in this year 
or next. 

6. Several personal com- 
puter manufacturers will in- 
troduce second-generation 
machines with significant in- 
creases in power. Score a 
"no." Although Apple, 
Tandy and Commodore all 
introduced new machines, 
none were significantly dif- 
ferent from their previous 
units. I look to 1981 for the 
introduction of a machine 
with significantly new per- 
formance versus price mark. 

7. The emphasis will shift 
from hardware to software. 
BASIC will continue as the 
dominant language. Score 
another "correct." This year 
should see continued im- 
provements in disk operat- 
ing systems and applications 
packages. 

8. Business application soft- 
ware for microcomputer sys- 
tems will finally come of age 
and provide the needed per- 
formance that suppliers have 
been promising but not de- 
livering during the past two 
years. Score a "correct." 

9. The first low-cost micro- 
computer-based robot kit 
will be introduced. Score an 
"incorrect." Although a 
robotic arm kit was intro- 
duced, its price was beyond 
the means of most personal 
computerists. Maybe this 
prediction will come true in 
1981. 

10. Typewriters will have 
built-in intelligence, and use 
microprocessors, built-in 
microdisks, and word pro- 
cessing features. The dumb 
typewriter will soon be a 
thing of the past. Score an 



"incorrect." Although Smith- 
Corona and Triumph-Adler 
introduced electronic type- 
writers, their intelligence is 
still on a primitive level. I 
am now projecting 1982 or 
1983 on this development. 
11. Personal computer time- 
sharing systems will pro- 
liferate. Score a definite 
"correct" on this one. 

All in all, I would rate my 
prediction ability as "fair": 
about sixty points out of a 
possible one hundred. 
Where I guessed wrong I was 
just ahead of the industry. 

I redlctlons For The 
Future: Not allowing my 
previous performance to 
deter me, I will venture forth 
with some more predictions: 

1. The S-100 will become 
the de facto standard for bus 
interfacing. There are al- 
ready thirty-two manufac- 
turers of S-100 systems, and I 
expect this number to in- 
crease to over forty in 1981 
(and to include IBM). This 
trend should continue into 
the mid-1980s, when we may 
see the development of a 
new interface bus to accom- 
modate new hardware and 
architectures. 

2. Hardware will become 
more sophisticated and less 
expensive. This is not a dif- 
ficult prediction to make, 
since Moore's law states that 
"the number of components 
per integrated circuit rough- 
ly doubles every year." 
Thus, personal computer 
systems will acquire the 
characteristics of their larg- 
er, more expensive predeces- 
sors. In other words, within 
three to five years we can ex- 
pect personal computers 
with the characteristics of 
large IBM 370s. The likeli- 
hood is that by the mid- 
1980s we will see a single 
package device containing 
processor, floating-point 
arithmetic, main memory 
and read-only memory with 
the complete operating sys- 
tem and a compiler or inter- 
preter. 

3. The man-machine inter- 
face will improve to accom- 
modate the many users who 



have little or no knowledge 
of computers. I therefore 
look for voice input/output 
to become commonplace by 
the end of the decade. Al- 
though voice input may be 
limited to short commands, 
output should be of a high 
quality with a large vocabu- 
lary. 

4. Cheap mass storage will 
finally arrive via video 
cassette and optical disk 
memories. We will be able 
to store 100,000 pages of 
printed text on a single op- 
tical (video) disk. ..expect to 
see the Encyclopaedia Bri- 
tannica on a single optical 
disk, with sophisticated 
cross-referencing software. 
Furthermore, expect optical 
disks that may be used with 
personal computers to pro- 
vide high-quality video im- 
ages for games, educational 
use, etc. 

5. Higher-quality displays 
using either liquid crystal or 
semiconductor technology 
will replace CRTs (cathode- 
ray tubes). 

6. Personal computers will 
include self-testing capa- 
bilities and redundant cir- 
cuits to improve reliability. 

7. Expect BASIC to continue 
as the dominant language. 
Assembler and Pascal will 
still be the most popular 
languages for systems-level 
programming, and C will in- 
crease in popularity. Natural 
programming languages and 
automatic programming still 
appear to be many years 
away. The number of menu- 
driven systems for the naive 
user will increase. 

8. Operating systems such 
as UNIX, CP/M, MP/M and 
more sophisticated systems 
will increase in popularity, 
and many manufacturers 
will design special hardware 
to support these operating 
systems. 

MAIL: I receive a large num- 
ber of letters each month as a 
result of this column. If you 
write to me and wish a re- 
sponse, please include a 
stamped, self-addressed enve- 
lope. 

Sol Libes 
POB 1 1 92 
Mountainside NJ 07092 



204 January 1981 © BYTE Publications Inc 



The 




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BYTE January 1981 207 



Product Review 



The Newest Sargon — 2.5 



John Martellaro 

2929 Los Amigos Ct Apt B 

Las Cruces NM 88001 



Time travel is common now. You've decided to spend 
the afternoon in Vienna on a sunny spring day in 1770. 
There is talk that at the Royal Palace the Baron Wolfgang 
von Kempelen, counselor to the Royal Chamber, will be 
giving a demonstration of his amazing Automaton Chess 
Player. You wander over towards the Palace. 

The murmur of the crowd grows as the Baron rolls a 
large wooden cabinet into the courtyard, the result of a 
solemn promise he made to the Queen 6 months ago to 
build a chess-playing machine. The Baron smiles gra- 
ciously and invites anyone to come forward from the 
crowd to play the Automaton. 

Meanwhile, the noblemen are about ready to accuse 
the Baron of a hoax. A machine that thinks? Rubbish. 
Sacrilege. And the spectators are no more convinced. 
Catcalls from the crowd dare the Baron to open the 
cabinet — obviously big enough to hold a small man — 
whereupon von Kempelen opens all the doors only to 
reveal a complex system of pulleys, gears, and levers, 
nothing else. 

About this time, you decide to come forth from the 
crowd to play this wondrous machine. Unknown to 
everyone, you have Sargon 6, no bigger than a match- 
book, hidden in your palm. With its aid, you win, but the 
Automaton plays a superb game. Afterwards, a crowd 
gathers around you, and the Baron congratulates you on 
your game. Everyone agrees that the machine played a 
creditable game of chess, clearly outplayed by a genius. 
A priest overhearing this remarks that this is proof of the 
superiority of the human mind. You shrug, put Sargon 6 
in your pocket, and wander off into the crowd. 

The Baron will go on to amaze the bewildered crowds 
in Europe and America for many years, and the machine 
will defeat many chess players. It will take 70 years for 
the hidden compartment and the hoax to be revealed. But 
the dream of a chess-playing machine is planted firmly in 
the minds of men. A dream which would take another 
200 years to come true. 

Introduction 

Sargon 6 isn't available yet, but Sargon 2.5 is. It is a 
game module and holder slightly larger than a hardback 
book, but the real guts are no larger than a pocket 
calculator. This is the MGS (Modular Game System) 
from Chafitz; as of this writing, it is the strongest chess- 
playing microcomputer you can buy. 

You may already be familiar with the Sargon 1 and 



Sargon 2.0 computer programs written by Dan and 
Kathe Spracklen. These are available on cassette or flop- 
py disk (from Hayden Books) for the Apple II and 
TRS-80 computers. But now Chafitz is marketing Sargon 
2.5 as a plug-in ROM (read-only memory) module that 
fits into the MGS. Presumably, when Sargon 3 and other 
versions are available, you can remove the old ROM and 
plug in the new one. Not only does this protect the firm- 
ware, but allows new games (such as checkers and 
backgammon) to be run on the same system. 

The technical specifications of the MGS-Sargon 2.5 
combination are many and impressive. The system is 
rather complete: a benefit of Chafitz's previous ex- 
perience with its chess machine, Boris. A touchpad 
keyboard allows the user to: 

• force selection of best move 

• use the machine in its hint mode 

• set playing level (from to 6) 

• set up a given position 

• show elapsed time (either player, cumulative, or time 
per move) 

• withdraw a move or moves (up to three moves) 



Af a danrp 


Name 


mable memory (for inter- 


Chafitz Modular Game 


nal use only) 


System with Sargon 2.5 






Additional features 


Manufacturer 


Includes AC adapter, 


Chafitz Inc, 856 Rockville 


keyboard, chessboard, 


Pike, Rockville MD 


magnetized chess pieces; 


20852, (301) 340-0200 


Sargon 2.5 is a re- 




movable module that can 


Price 


be replaced by other 


$375 


game modules (not yet 




released) 


Processor 




6502, 8-bit 


Software 




Sargon 2.5 program, held 


System-clock frequency 


in 8 K bytes of ROM 


2 MHz 






Options 


Memory 


Rechargeable battery 


2 K bytes of program- 


option 



208 January 1981 © BYTE Publications Inc 




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TRS-80 



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DEALER INQUIRIES INVITED 




Sicilian Defense 


White 




Black 


Martellaro 




Sargon 2.5 (level 4) 


1 . e2-e4 




c7-c5 


2. Ng1-f3 




d7-d6 


3. Bf1-b5 ch 




Bc8-d7 


4. Bb5-c4 




Nb8-c6 


5. Nb1-c3 




Ng8-f6 


6. d2-d4 




c5xd4 


7. Nf3xd4 




Qd8-b6 


8. Bc1-e3 




Qb6xb2?? 


9. Nd4-b5 




Ra8-c8 


10. Ra1-b1 




...and Black loses his Queen 


Table 1: Beginning 


of a 


chess game between the author and 


Sargon 2.5. 







The system is very nicely packaged. The quality of the 
plastic case and the display is outstanding. In the instruc- 
tion manual there is a brief rule description of chess and 
information on the USCF (United States Chess Federa- 
tion). This is an important and welcome addition. 
Overall, the instructions are clear and easy to under- 
stand. For once, we have complete documentation. 

A conversation with Kathe Spracklen revealed that the 
decision algorithms of Sargon 2.5 are exactly the same as 
those of Sargon 2.0. The only modification is that the 
host 6502 microprocessor runs at 2.0 MHz as opposed to 
the Apple's effective 1.0 MHz, and Sargon 2.5 thinks on 
its opponent's time. The result of this is that Sargon 2.5 is 
often ready with a move as soon as the opponent enters 
his move. The program uses 8 K bytes of ROM and 2 K 
bytes of programmable memory. 

Playing Strength 

When chess programs were first written for microcom- 
puters (Microchess 1.0 on the KIM and Sol), we all 
laughed and proceeded to demolish them. While we had 
respect for the programs on big computers, microcom- 
puter chess programs had a poor reputation. Times have 
changed, and now the average player can no longer bully 
microcomputer-based chess programs. That is not to say 
that Sargon can't be beaten by a good player. (Some 
results are given here; see tables 1 and 2.) But now a 
player must use care and caution, and a single slip can 
mean disaster. 

Sargon 2.5 in experimental form obtained a USCF 
rating of 1641 in a rated human tournament (the 1979 
Paul Masson Championship). This is not bad at all for a 
machine that plays under tournament time controls and 
can be held in the palm of your hand. Reportedly, the 
Spracklens are working on major improvements that will 
boost its rating (Sargon 3) to 1800 in tournament time. 
Sargon 2.5 is probably the last microcomputer program 
that we amateur players will be able to consistently beat. 

Playing Results 

In a match of five games between Sargon 2.5 and 
Sargon 2.0 (which runs on my Apple II), the programs 
split — two wins, two losses each, and a declared draw. 
Sargon 2.5 started out slowly indeed. I didn't mind too 
much when I (rated about 1700) and a friend (rated 1850) 



210 January 1981 © BYTE Publications Inc 



When it comes to 6800 
Software Source Books; 
Hemenway delivers what 
the others leave out. 



...including complete source listings, 
complete descriptions of all algorithms used, 
and complete manuals of the products. 



SP/68 OPERATING SYSTEM STRUCTURED BASIC LANGUAGE 

One of the most powerful operating systems STRUBAL+'" COMPILER 

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sors, this disc-based system features great from 4 to 14 digits for business or scientific 

flexibility. The user can add commands for uses and Structured Programming forms. It 

special purposes. A single transient Periph- produces Relocatable and linkable code. You 

eral Interchange Program (PIP) transfers data can create data structures with mixed data 

between devices. The system is relocatable types, COMMON and DUMMY sections. 



anywhere in memory and fits in less than 8K. 
Other features include device-independent 
I/O and dynamic file allocation. 

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International $52.45 

XA6809 MACRO LINKING 
CROSS-ASSEMBLER 

This new two-pass program generates relo- 
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Resident on any 6800 system, XA6809 lets 
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a COMMON section for the production of 
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If your machine 
would like to read 
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object code versions 
are available in these 
disk formats: Per- 
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SWTPC, TANO and 
others. 

WRITE FOR PRICES 



Please rush the following books: 

copies of SP/68 OPERATING SYSTEM 

copies of XA6809 CROSS ASSEMBLER 

copies ofLINK68 LINKING LOADER 

copies of RA6800ML MACRO ASSEMBLER 

copies of STRUBAL+™ COMPILER 

copies ofTRACER DEBUGGING PROGRAM 

For North America, add $.75 per book postage or $1.50 per book for 
First Class. All other destinations, add $2.00 per book postage and 
handling or $3.50 per book for Priority Mail. 



LINK68 LINKING LOADER 

This is a one-pass linking loader which allows 
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U.S. $7.95 

International $11.95 
RA6800ML RELOCATABLE MACRO 
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6800 assembly language and all major rou- 
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interfacing the assembler. Cross referenced, 
showing all calling and called-by routines, 
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_., U.S. $24.95 

International $37.95 



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4 






ArJsr 



BYTE January 1981 211 



Grunfeld-lndian Defense 


18. g2xf3 
19.0-0 


Qe4-f5 


White Black 


Taunting Sargon 2.0 to do any harm... 


Sargon 2.5 (level 4) Sargon 2.0 (level 3) 


19 


b7-b5 


1 . d2-d4 Ng8-f6 

2. c2-c4 g7-g6 


20. Bc4-b3 

21. Bc7-g3 


Qf5-g5 ch 
Qg5-f6 


3. Nb1-o3 d7-d5 


22. Rc3-c5 


a7-a6 


4. c4xd5 Nf6xd5 


23. Bb3-d5 


Ra8-d8 


5. Nc3xd5 Qd8xd5 


24. Qd1-c2 




6. Ng1-f3 Bf8-g7 

7. Bc1-f4 


Threatening, of course, 


25. Rc5-c8. 




24 


Qf6-f5 


This gets the Bishop developed in preparation for 8. e2-e3. 


25. Qc2xf5 


g6xf5 


Nb8-c6 


26. Bd5-b7 


e7-e6 


8. e2-e3 Qd5-a5 ch 


27. Bb7xa6 


b5-b4 


9. Qd1-d2 Nc6-b4! 


28. Rc5-c4 


Rd8-a8? 


Not a bad move for a $30 program. But it will be fruitless. 


Black was in serious trouble, but there was no reason to allow the 
following clincher. 


10. Ra1-c1 Bc8-f5 






11,Rc1-c5 Qa5-b6 


29. Bg3-d6 ch 


Kf8-e8 


12. Bf4xc7 Nb4-c2 ch 


30. Ba6-b5 ch 




Sargon 2.0 has been wanting to do this badly. Now, however, it is 


The mating web starts. 


• 


in vain. 


30 


Ke8-d8 


13. Rc5xc2 Qb6-e6 


31. Rc4-c7 


Ra8-a5 


14. Bf1-b5ch Ke8-f8 


32. Rc7-b7 




15. Bb5-c4 Qe6-e4 


Threat: Rb7-b8 mate. 




16. Rc2-c3 Bf5-g4 

17. Qd2-d1 


32 

33. Rb7-d7 ch 


Ra5-a8 
Kd8-e8 


Sargon 2.5 is finding all the right defensive moves and is a pawn 


34. Rd7-a7 ch 


Ke8-d8 


and Knight to the good. 


35. Ra7xa8 mate 




17 Bg4xf3 






Table 2: Record of a complete chess game between Sargon 2.5 (running on the Chafitz Modular Game System) and Sargon 2.0 


(running on an Apple II computer). 







Technical Notes on Sargon 2.5 and the Chafitz 
Modular Game System 

The NIGS is a plastic case with a slide-out tray. The 
top of the chessboard is brown and white soft grain 
with algebraic-notation markings. In the tray is the 
receptacle for the plug-in ROM, a keyboard (supplied 
with a chess overlay), and a compartment with chess- 
men — standard Staunton chess pieces, magnetized, 
with a 2V*-inch King. There is an AC (alternating cur- 
rent) adapter supplied. An optional battery pack is 
available for $39. 95; on battery power, the unit can re- 
tain an adjourned position for about 24 hours. The 
total system price is $375. 

Sargon 2.5 plays at six levels. Level 4 gives a reply in 
2 to 4 minutes, plays in tournament time, and is rated 
1641. If you want to wait 20 to 40 minutes per move at 
level 5, the claimed rating is 1800. 



took three games from Sargon 2.5. But when Sargon 2.0 
won its first two games, apprehension mounted. We 
wondered if there was a faulty ROM in Sargon 2.5, but 
we decided it was unlikely. Later, Sargon 2.5 came back 
to win two straight games against Sargon 2.0 and redeem 
itself (see match results, table 3). 

The circumstances of the first two losses to Sargon 2.0 
are peculiar. In the first game, everything was even down 
to pawns and King against pawns and King. But Sargon 
2.0 gained a tempo (an advantage in time) and promoted 
a pawn to Queen before Sargon 2.5 could. In the second 
game, Sargon 2.5 played very speculatively on the attack 
and lost a Bishop for a pawn, then later another pawn. A 
whole Bishop down going into the end game with no 



Opponent of 
Sargon 2.5 

Martellaro 

J. Irwin 
Sargon 2.0 



USCF 
Rating 

(1700 + ) 
(1850) 
(1600?) 



Results 

2 wins, 1 loss 

1 win 

2 wins, 2 losses, 1 draw 



Table 3: An informal list of match results between Sargon 
2.5 and other opponents. 



compensation whatsoever caused me to declare a win for 
Sargon 2.0. 

This is hard to quantify or justify, but it appears that 
Sargon 2.5 with its greater look-ahead capability plays 
more (what I would call) speculatively. Sargon 2.5 will 
play solid defense and sacrifice soundly, but it also ap- 
pears to play a little more aggressively and loosely than 
Sargon 2.0. Sargon 2.0 is very solid and conservative and 
never risks too much. Because of this, Sargon 2.5 can get 
into trouble on the offensive. 

It is also peculiar that in the games Sargon 2.5 won, it 
was on the defensive with White. (See the game score in 
table 2.) Sargon 2.0 huffed and puffed on the attack with 
Black for twenty moves, flailing away. When Sargon 2.5 
was done fending off the attack, it was a Bishop and two 
pawns up and proceeded to mate. Astonishing. 

The difference in strength between Sargon 2.5 and 
Sargon 2.0 seems small yet definite. My personal subjec- 
tive experience is that Sargon 2.5 is more resilient on the 
defense, and I would prefer to play Sargon 2.0 as the 
weaker opponent. However, if you are running Sargon 
2.0 on your microcomputer, the $300-plus investment for 
the "improved" version is hardly worth it. Wait for 
Sargon 3.B 



212 January 1981 © BYTE Publications Inc 




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BYTE January 1981 213 



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Circle 134 on Inquiry card. 




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BYTE January 1981 




Product Review 



The SwTPC 6809 Microcomputer System 



Tom Harmon, 1505 Magnolia Dr, Salisbury MD 21801 



The SwTPC 6809 microcomputer system can be pur- 
chased in kit form (as the 69/K) for $495 or assembled 
and tested (the 69/A) for $595. Since I wanted to add 
sockets for all the integrated circuits, I chose the kit. (The 
assembled version doesn't use sockets.) 

The 69/K and 69/A systems both include the MP-09 
processor board, one MP-8M 8 K-byte programmable 
memory board, the MP-S2 RS-232C serial-interface card, 
and the MP-B3 motherboard with eight 50-pin slots and 
eight 30-pin slots. The case and power supply are also in- 
cluded. 

The Processor Board 

The MP-09 uses the Motorola 6809 microprocessor 
with a 1 MHz clock. The 6809 is the third-generation ad- 



Af a nianrp 


Name 


Hardware 


69/K (kit) or 69/A 


RS-232C terminal (for 


(assembled) computer 


input and output) 


Use 


Software 


6809-based personal 


SBUG-E monitor in ROM 


computer 


(included) 


Manufacturer 


Hardware Options 


Southwest Technical 


extra memory boards, 


Products Corp, 219 W 


expansion kit for serial 


Rhapsody, San Antonio 


interface, MF-69 5-inch 


TX 78216 (512) 344-0241 


floppy-disk system (in- 




cludes FLEX operating 


Dimensions 


system) 


length: 44 cm (17 inches) 




width: 39 cm (15 inches) 


Software Options 


height: 18 cm (7 inches) 


FLEX disk operating 




system, other software 


Price 


products from TSC (see 


$495 (for 69/K), $595 


text) that are supported 


(for 69/A) 


by SwTPC 


Features 


Documentation 


processor board contain- 


looseleaf pages, 22 by 28 


ing 6809 microprocessor 


cm (8V2 by 11 inches), in 


running at 1 MHz, 


binder, with separate sec- 


RS-232C serial-interface 


tions on kit construction 


card, 8 K bytes of pro- 


(if applicable), sche- 


grammable memory, fan 


matics, parts layout, 




operation 



dition to the 8-bit 6800 family. It includes two 16-bit in- 
dex registers, two 16-bit stack pointers, two 8-bit ac- 
cumulators which can be treated as a single 16-bit register 
for some operations, and a direct-page register for direct- 
memory addressing. The 6809 includes all addressing 
modes of the 6800 with the addition of program-counter 
relative, extended indirect, indexed indirect, and 
program-relative indirect. Assembly language written 
with program-counter relative mode can be moved 
anywhere in memory without reassembly. 

The 6809 is not object-code compatible with the 6800. 
Although 6800 source code can be reassembled with 
minor changes, the code should be rewritten to take full 
advantage of 6809 capabilities. 

Sockets are provided on the board for three additional 
2716 EPROMs (erasable programmable read-only 
memory devices). However, the documentation says the 
physical addresses of these may conflict with interface 
addresses and recommends they be switched off. 

Included on the processor board is an integrated circuit 
that creates clock signals for various data-transfer rates. 
Because of the shortage of pins on the SS-50C bus, some 
of the clock signals share common bus lines and are 
jumper-selected. 

A DAT (dynamic address translator) allows physical 
memory to be assigned as logical memory in any desired 
order. Because of this, you don't have to strap memory 
boards into consecutive memory locations. The principal 
use for the DAT will be for multiuser/multitasking soft- 
ware, which is still being developed. 

A welcome feature is that the memory addresses used 
for input and output have been moved to a higher loca- 
tion to allow the 6809 to support 56 K bytes of program- 
mable memory instead of the 32 K bytes supported on 
older SwTPC 6800 systems. 

The MP-09 processor board is silk-screen masked and 
is of much higher quality than the memory board sup- 
plied with the kit. The MP-09 board is intended for use 
with the SS-50C bus and cannot be used with the older 
SS-50 bus unless modifications are made to the mother- 
board. 

The SBUG-E Monitor 

A 2 K-byte monitor (SBUG-E) is supplied in a ROM 
(read-only memory) that is pin compatible with a 2716 
EPROM. The monitor contains disk bootstrap routines 
for both 5-inch and 8-inch floppy disks. A new DC-3 
double-head single-density disk controller that is com- 



216 January 1981 © BYTE Publications Inc 



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Circle 137 on Inquiry card. 



BYTE January 1981 217 




Photo 1: The SwTPC 6809 microcomputer system. The factory- 
assembled 69/ A sells for $595 and includes the three boards 
shown here. Front to back are the MP-09 processor board, the 
MP-8M memory board, and the MP-S2 RS-232C serial-interface 
board. The kit version 69/K is $495. 



Photo 2: The MP-8M programmable memory board for the 
SwTPC 6809 microcomputer system. Both the kit and as- 
sembled versions of the computer are shipped with one of these 
8 K-byte boards. This board is addressable to any 8 K-byte 
boundry within the first 32 K bytes of memory. 



patible with the SS-50C bus is available from SwTPC for 
$150. The older MF-68 disk controller cannot be used 
with the SS-50C bus without modification. It has been 
rumored that SwTPC may soon discontinue the MF-68 
floppy-disk drive and replace it with a DT-5 unit, which 
uses the Siemens double-head drive. 

The SBUG-E monitor also includes a memory 
diagnostic. It allows you to set and release breakpoints, 
examine and alter memory, and examine and alter 6809 
registers. Unfortunately, SwTPC does not provide source 
listings of SBUG-E. However, a disassembled source 
listing has been published in 68 Micro Journal (June 
1980). 

Serial Interface 

The MP-S2 serial-interface card is supplied set up for 
one serial port. It can be expanded to two ports by order- 
ing the MP-SX expansion kit, which sells for $25. The 
card must be installed in bus-row 0, driving the system 
console with a standard RS-232C port. A nice feature is 



that you don't need extra cables or connectors since the 
DB-25 connector is mounted directly on the card. 

Other Features 

The MP-B3 motherboard uses the new SS-50C bus. 
Since I/O cards have decoding performed for sixteen ad- 
dresses, the new cards are not downwards compatible 
with the SS-50 bus. 

The power supply provides unregulated outputs of 
±16 VDC and +8 VDC. Older SS-50 cards that 
obtained 12 VDC from the bus will now require on-board 
regulators. 

The 6809 cabinet is constructed of heavy anodized 
aluminum and is a major improvement on the older 
SwTPC systems. I had no trouble getting the bolt holes to 
align perfectly. 

The quality of the parts supplied with the 69/K kit is 
excellent. I did find several small components missing 
from the kit but had no trouble getting replacement parts 
from SwTPC. 



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Hawaii, Canada, $25 air mail to all other countries 

We manufacture a complete line of high quality expansion boards. Use reader service card to be added 
to our mailing list, or U.S. residents send $1.00 (International send $3.00 U.S.) for airmail delivery of our 
complete catalog. 

ENTERPRISES 

NCORPORATED 
2951 W. Fairmount Avenue • Phoenix, AZ 85017 • (602) 265-7564 




218 January 1981 © BYTE Publications Inc 



Circle 138 on inquiry card. 



DYNACOMP 



Quality software for: 

ATARI 

PET 

APPLE II Plus 



TRS-80 (Level ID- 
NORTH STAR 
CP/M 8" Disk 



GAMES 

BRIDGE 2.0 (Available for all computers) Price: $17.95 Cassette 

$21.95 Diskette 

An all-inclusive version of [his most popular of card games. This program both BIDS and PLAYS 
either contract or duplicate bridge. Depending on the contract, your computer opponents will either 
play the offense OR defense. If you bid too high, the computer will double your contract! BRIDGE 2.0 
provides challenging entertainment for advanced players and is an excellent learning tool for the bridge 



HEARTS 1.5 (Available for all computers) 



Price: $14.95 Cassette 
$18.95 Diskette 

An exciting and entertaining computer version of this popular card game. Hearts is a trick-oriented 
game in which the purpose is not to take any hearts or the queen of spades. Play against two computer 
opponents who are armed with hard-to-beat playing strategies. 

CRIBBAGE 2.0 (TRS-80 only) Price: $14.95 Cassette 

$18.95 Diskette 

This is a well-designed and nicely executed two-handed version of the classic card game, cribbage. It is 
an excellent program for the cribbage player in search of a worthy opponent as well as the beginner 
wishing to learn the game, in particular the scoring and jargon. The standard cribbage score board is 
continually shown at the top of the display (utilizing the TRS-80's graphics capabilities), with the cards 
shown underneath. The computer automatically scores and also announces the points using the tradi- 
tional phrases. 

CHESS MASTER (North Star and TRS-80 only) Price: $19.95 Cassette 

$23.95 Diskette 

This complete and very powerful program provides five levels of play. It includes castling, en passant 
captures and the promotion of pawns. Additionally, the board may be preset before the start of play, 
permitting the examination of "book" plays. To maximize execution speed, the program is written in 
assembly language (by SOFTWARE SPECIALISTS of California). Full graphics are employed in the 
TRS-80 version, and two widths of alphanumeric display are provided to accommodate North Star 
users. 

STARTREK 3.2 (Available for all computers) Price: $ 9.95 Cassette 

$13.95 Diskette 

This is the classic Starirek simulation, but with several new features. For example, the Klingons now 
shoot at the Enterprise without warning while also attacking starbases in other quadrants. The 
Klingons also attack with both light and heavy cruisers and move when shot at! The situation is hectic 
when the Enterprise is besieged by three heavy cruisers and a starbase S.O.S. is received! The Klingons 
get even! 

SPACE TILT (Apple only) Price: $10.95 Cassette 

$14.95 Diskette 

Use the game paddles to tilt the plane of the TV screen to "roll" a ball into a hole in the screen. Sound 
simple? Not when (he hole gets smaller and smaller! A built-in timer allows you to measure your skill 
against others in this habit-forming action game. 

GAMES PACK I and GAMES PACK II Price: $ 9.95 each, Cassette 

$13.95 each, Diskette 

GAMES PACK I contains BLACKJACK, LUNAR LANDER, CRAPS, HORSERACE, SWITCH 
and more. GAMES PACK II includes CRAZY EIGHTS, JOTTO. ACEY-DUCEY. LIFE. VVUMPUS 
and others. Available for all computers. 
Why pay S5.95 or more per program when you can buy a DYNACOMP collection for just $9.95? 

STUD POKER (ATARI only) Price: $11.95 Cassette 

$15.95 Diskette 

This is the classic gambler's card game. The computer deals the cards one at a time and you (and the 
computer) bet on what you see. The computer does not cheat and usually bets ihe odds. However, it 
sometimes bluffs! Also included is a five card draw poker betting practice program. This package will 
run on a 16K ATARI. 



STATISTICS and ENGINEERING 

DATA SMOOTHER (Not available for ATARI) Price: $14.95 Cassette 

$18.95 Diskette 

This special data smoothing program may be used to rapidly derive useful information from noisy 
business and engineering data which are equally spaced. The software features choice in degree and 
range of fit, as well as smoothed first and second derivative calculation. Also included is automatic 
plotting of the input data and smoothed results. 

FOURIER ANALYZER (Available for all computers) Price: $14.95 Cassette 

$18.95 Diskette 

Use this program to examine the frequency spectra of limited duration signals. The program features 
automatic scaling and plotting of the input data and results. Practical applications include the analysis 
of complicated patterns in such fields as electronics, communications and business. 

TFA (Transfer Function Analyzer) Price: $19.95 Cassette 

$23.95 Dbkette 

This is a special software package which may be used to evaluate the transfer functions of systems such 
as hi-fi amplifiers and filters by examining their response to pulsed inputs. TFA is a major modification 
of FOURIER ANALYZER and contains an engineering-oriented decibel versus log-frequency plot as 
well as data editing features. Whereas FOURIER ANALYZER is designed for educational and scien- 
tific use, TFA is an engineering tool. Available for all computers. 

FOURIER ANALYZER and TFA may be purchased together for a combined price of S29.95 
(Cassettes) and $37.95 (Diskettes). 

REGRESSION I (Available for all computers) Price: $19.95 Cassette 

$23.95 Dbkette 

REGRESSION I is a unique and exceptionally versatile one-dimensional least squares "polynomial" 
curve fitting program. Features include very high accuracy; an automatic degree determination option; 
an extensive internal library of fitting functions; data editing; automatic data and curve plotting; a 
statistical analysis (e.g., standard deviation, correlation coefficient, etc.) and much more. In addition, 
new fits may be tried without reentering the data. REGRESSION I is certainly the cornerstone program 
in any data analysis software library. 

REGRESSION II (PARAFIT) (Available for all computers) Price: $19.95 Cassette 

$23.95 Diskette 

PARAFIT is designed to handle those cases in which the parameters are imbedded (possibly nonlinear- 
ly) in the fitting function. The user simply inserts the functional form, including the parameters (A(l), 
A(2), etc.) as one or more BASIC statemeni lines. Data and results may be manipulated and plotted as 
with REGRESSION I. Use REGRESSION I for polynomial fitting, and PARAFIT for those com- 

plicited functions. 

REGRESSION I and II may be purchased together for S36.95 (cassettes) and $44.95 (diskettes) 



Availability 

DYNACOMP software is supplied with complete documentation containing clear explanations and 
examples. All programs will run within 16K program memory space (ATARI requires 24K). Except where 
noted, programs are available on ATARI, PET, TRS-80 (Level II) and Apple (Applesoft) cassette and 
diskette as well as North Star single density (double density compatible) diskette. Additionally, most pro- 
grams can be obtained on standard 8" CP/M floppy disks for systems running under MBASIC. 



BUSINESS and UTILITIES 
MAIL LIST II (North Star only) Price: $21.95 

This many-featured program now includes full alphabetic and zip code sorting as well as file merging. 
Entries can be retrieved by user-defined code, client name or Zip Code. The printout format allows the 
use of standard size address labels. Each diskette can store more than 1 100 entries (single density; over 
2200 with double density systems)! 

TEXT EDITOR I (Letter Writer) Pr ke: $14.95 Cassette 

$18.95 Diskette 

An easy to use, line-onented text editor which provides variable line widths and simple paragraph in- 
dexing. This text editor is ideally suited for composing letters and is quite capable of handling much 
larger jobs. Available for all computers. 

PERSONAL FINANCE SYSTEM (ATARI only) Price: $34.95 Diskette 

PFS is a single disk menu oriented system composed of 10 programs designed to organize and simplify 
your personal finances. Features include a 300 transaction capacity; fast access; 26 optional user codes; 
data retrieval by month, code or payee; optional printing of reports; checkbook balancing; bar graph 
plotting and more. Also provided on the diskette is ATARI DOS 2. 

FINDIT (North Star only) Price: $19.95 

This is a three-in-onc program which maintains information accessible by keywords of three types: Per- 
sonal (e.g., last name), Commercial (eg: plumbers) and Reference (eg: magazine articles, record 
albums, etc). In addition to keyword searches, there are birthday, anniversary and appointment search- 
es for the personal records and appointment searches for the commercial records. Reference records 
arc accessed by a single keyword or by cross-referencing two or three keywords. 

DFILE (North Star only) Price: $19.95 

This handy program allows North Star users to maintain a specialized data base of all files and pro- 
grams in the stack of disks which invariably accumulates. DFILE is easy to set up and use. It will 
organize your disks to provide efficient locating of the desired file or program. 

COMPARE (North Star only) Price: $12.95 

COMPARE is a single disk utility software package which compares two BASIC programs and dis- 
plays the file sizes of the programs in bytes, the lengths in terms of the number of statement lines, and 
the line numbers at which various listed differences occur. COMPARE permits the user to examine ver- 
sions of his software to verify which are the more current, and to clearly identify the changes made dur- 
ing development. 

COMPRESS (North Star only) Price: $12.95 

COMPRESS is a single-disk utility program which removes all unnecessary spaces and (optionally) 
REMark statements from North Star BASIC programs. The source file is processed one line at a time, 
thus permitting very large programs to be compressed using only a small amount of computer memory. 
File compressions of 20-50W are commonly achieved. 

GRAFIX (TRS-80 only) Prke: $12.95 Cassette 

$16.95 Diskette 

This unique program allows you to easily create graphics directly from the keyboard. You "draw" 
your figure using the program's extensive cursor controls. Once the figure is made, it is automatically 
appended to your BASIC program as a string variable. Draw a "happy face", call it HS and then print 
it from your program using PRINT HS! This is a very easy way to create and save graphics. 

TIDY (TRS-80 only) Price: $10.95 Cassette 

$14.95 Diskette 

TIDY is an assembly language program which allows you to renumber the lines in your BASIC pro- 
grams. TIDY also removes unnecessary spaces and REMark statements. The result is a compacted 
BASIC program which uses much less memory space and executes significantly faster. Once loaded, 
TIDY remains in memory; you may load any number of BASIC programs without having to reload 
TIDY! 



SIMULATIONS and EDUCATION 

BLACK HOLE (Apple only) Price: $14.95 Cassette 

$18.95 Diskette 

This is an exciting graphical simulation of the problems involved in closely observing a black hole with 
a space probe. The object is to enter and maintain, for a prescribed time, an orbit close to a small black 
hole. This is to be achieved without coming so near the anomaly that the tidal stress destroys the probe. 
Control of (he craft is realistically simulated using side jets for rotation and main thrusters for accelera- 
tion. This program employs Hi-Res graphics and is educational as well as challenging. 

V ALDEZ (Available for all computers) Price: $14.95 Cassette 

$18.95 Diskette 

A simulation of supertanker navigation in the Prince William Sound and Valdez Nanows. The pro- 
gram uses an extensive 256X256 element radar map and employs physical models of ship response and 
tidal patterns. Chan your own course through ship and iceberg traffic. Any standard terminal may be 
used for display. 

FLIGHT SIMULATOR (Available for all computers) Price: $17.95 Cassette 

$21.95 Diskette 

A realistic and extensive mathematical simulation of take-off, flight and landing. The program utilizes 
aerodynamic equations and the characteristics of a real airfoil. You can practice instrument approaches 
and navigation using radials and compass headings. The more advanced flyer can also perform loops, 
half-rolls and similar aerobatic maneuvers. 

TEACHER'S PET I (Available for all computers) Price: $ 9.95 Cassette 

$13.95 Diskette 

This is the first of DYNACOMP's educational packages. Primarily intended for pre-school to grade 3, 
TEACHER'S PET provides the young student with counting practice, letter-word recognition and 
three levels of math skill exercises. 



Ordering Information 



All orders are processed and shipped postpaid within 48 hours. Please enclose payment with order along 
with computer information. If paying by VISA or Master Card, include all numbers on card. For orders 
outside North America add 10ft for shipping and handling. 

Add S2.50 to diskette price for 8" floppy disk (soft sectored, CP/M, Microsoft BASIC) 
'TRS-80 diskettes are not supplied with DOS or BASIC. 

Deduct 10% when ordering 3 or more programs. 

Ask for DYNACOMP programs at your local software dealer. Write for detailed descriptions of these and 
other programs from DYNACOMP. 



DYNACOMP, Inc. 

6 Rippingale Road 
Pittsford, New York 14534 

(716) 586-7579 

New York Suit residents pleue add 7tt NVS sales las. 



Circle 139 on inquiry card. 



BYTE January 1981 219 



31^^S 1^\ The improved 
3l\^J l\/« version of BKG9.8, 
the BACKGAMMON playing program that 
defeated the '79'-'80 World Backgammon 
Champion by a score of 7-1! 

f'%,^ BKQl6.,developed°with the 

help of Paul Magriel former 
? world champion and author 

of BACKGAMMON, has 
emerged as one of the 
best examples of artificial 
| intelligence software 

available for micro- 
computers. 



Vers I $79. 

^ Vers II $129. 
FEATURES: 

* Version I: Full direct cursor screen control for professional 
display of beard, dice, etc. 

* Version II adds printer/ disk output of game in progress, 
board initialization at non standard positions, and simulation 
capabilities. 

* BKG 10. utilizes advanced SNAC functions (smooth, 
nonlinear application coefficients) as described in Scientific 
American, June, 1 980. 

* Complete game rules including: doubling, match play and 
Crawford Rule. Will play man-machine, either side or 

.i machine-machine with Version II. 

' BKG 10. makes most moves in under 20 seconds (2MHZ) 
or 10 seconds (4 MHZ). 

* BKG 10. was written entirely in Z-80 assembler. 



ANNOUNCING: 



G OMO K U 



Compete against 

your machine to 

arrange five stones in a 

row on a 19 by 19 matrix. ! ! 

Play this game for fun but be prepared for defeat as 
it exploits your human weaknesses in this entirely 
logical game. You may allow yourself a handicap, ask 
for the prefrred move, store a game position, recall a 
game from disk, output a game to the printer or re- 
play a game from memory for study. 



• SYSTEM REQUIREMENTS • 

Z-80 Processor, 40k CP/M for BKG 10 Vers I, 48k for BKG 10 Vers II 
and GOMOKU, cursor addressable video terminal (specify terminal 
model, most makes supported), 8" or 5^4" floppy drive. Formats 
available for TRS-80 Model II, Northstar, Cromemco, others. 



For MasterCard and CODs only- 

CALL NOW (800) 824 -7888 

in California: 800-852-7777 
in Alaska/ Hawaii: 800-824-7919 

please ask for Operator 105 



Intelligence Systems Ltd.. Indianapolis. IN - (317) 631-5514 



The documentation supplied with the 69/K system is 
adequate, but the construction manuals are not as de- 
tailed as those of some other manufacturers. For exam- 
ple, you are told to install all resistors as a single step in 
construction, and you are expected to know the resistor 
color codes and be able to identify the polarity of all 
polarized capacitors. I would not recommend this kit for 
a beginning kit builder. However, an experienced builder 
should have no trouble. 

Construction Hints 

I selected low-profile tin soldier-tail sockets manufac- 
tured by Texas Instruments for use on the printed-circuit 
boards. These sockets may be purchased from a number 
of sources, including Digi-Key Corporation, POB 677, 
Highway 32 S, Thief River Falls MN 56701. 

The straight pin-edge connectors on the motherboard 
seem to slope in one direction and the 10-pin male con- 
nectors should be installed with the slope in the same 
direction. This avoids problems when the printed-circuit 
boards are inserted later. You might also find it easier to 
remove the socket index pin before soldering the sockets 
to the board. 



The Added Extras 

In order to communicate with your microcomputer 
system, you'll need an RS-232C-compatible terminal. I 
selected the Heath H-19 video terminal over the SwTPC 
CT-82 because I prefer the larger 12-inch display size of 
the Heath. (The SwTPC CT-82 has a 9-inch display.) The 
normal format of the Heath H-19 is 24 lines by 80 
characters, while the CT-82 format is 16 lines by 82 
characters. 

You'll probably want additional memory because only 
4 K bytes of the supplied 8 K bytes of programmable 
memory are available for use. The SBUG-E monitor 
assigns a 4 K-byte area for a system stack and for internal 
tables and addresses. SwTPC sells additional MP-8Mb 
bare boards with edge connectors for $17. By buying 
your own integrated circuits and memory from indepen- 
dent suppliers, you can save a considerable amount of 
money over assembled units. 

Digital Research Computers (POB 401565, Garland TX 
75040) sells a 16 K-byte programmable memory board 
for the SS-50 bus ($26). The board uses type-2114 in- 
tegrated circuits instead of the type-4044 programmable 
memory devices used by the MP-8M board. The quality 
is excellent and well worth adding to your 6809 system. 

Of course you'll also need either a cassette-tape unit 
(like the SwTPC AC-30) or a floppy-disk system for 
loading and saving programs. 

Software 

The FLEX 09 version 2.6 disk operating system is 
available from SwTPC. The price ($35) includes a 
manual and object-code disk. FLEX 09 can be used with 
most of the 6809 software available from TSC (Technical 
Systems Consultants, POB 2574, West Lafayette IN 
47906). TSC has a large amount of 6809 software, in- 
cluding a text editor, an assembler, several versions of 
BASIC, a debugging package, and others. 

CSI (Control Systems Inc, 1317 Central, Kansas City 
KS 66102) has the UCSD Pascal compiler for $419 that 

Circle 140 on inquiry card. 




PET and the 

IEEE 488 Bus 

(GPIB) 

by E. Fisher and 
C. W Jensen 



This is the only complete guide available on 
interfacing PET to GPIB. Learn how to program 
the PET interface to control power supplies, 
signal sources, signal analyzers and other 
instruments. It's full of practical information, as 
one of its authors assisted in the original design 
of the PET GPIB interface. 

#31-4 $15.99 



NEWPET/CBM 
edition 



Some Common 
BASIC Programs 

by L. Poole, M Borchers, 
C. Donehue 

76 Programs you cen use even if you don't 
know BASIC. This book gives you e variety of 
math power including personal finance, taxes 
and statistics as well as other programs you'll 
want like Recipe Cost and Check Writer. All 
programs can be run on a PET or CBM with 8K 
or more. 

#40-3 $14.99 





PET owners can purchase the programs ready- 
to-run on cassette or disk. Use the book as a 
manual for operating instructions and 
programming options. 

Disk #33-0 $22.50 
Cassette #25-X $15.00 

Practical BASIC Programs 

ed. Lon Poole 

These are 40 easy to use programs that 
each do something useful. 

Income averaging, checkbook reconciliation, 
statistics, factorials, temperature conversion 
and musical transposition are just a few. It offers 
a wealth of practical computing power. Includes 
write-ups, program notes and instructional 
examples to help you realize the potential uses 
of each program. 

#38-1 $15.99 

6602 

Assembly Language 

Programming 

by L. Leventhal 

Increase the capabilities and performance of 
PET (end other 8502-based computers) by 
learning to program in assembly language. 

#27-6 $16.99 



New for your PET 



from 



{j\ OSBORNE/McGraw-Hill 




PET™/CBM™ Personal Computer Guide 
Second Edition 

by Adam Osborne and Carroll S. Donahue 

The PET/CBM Personal Computer Guide is a step-by-step guide that assumes no 
prior knowledge of computers. If you can read English, you can use this book. 

This book provides the important information and documentation that PET/CBM 

users have sought for so long. After reading this book you will have 

a good understanding of what a computer — 

especially the PET/CBM 

computer — can do for you. If you've just / j^ 

bought a PET or CBM this is the book you 

must have to really understand your 

computer. By using the examples 

found in this book, you will quickly 

get your PET/CBM up and running. These 

examples are thoroughly documented so 

you can learn how and why the programs 

work. It is the "how" and the "why" that 

are important if you want to learn how to 

make your PET or CBM work efficiently 

for you. 

This second edition contains even more 

useful information than the first 

edition of this book. 

The guide contains a wealth of 

information on everything 

from keyboard variations 

to a detailed description 

of PET and CBM memory. 




Included are: 

Complete operating instructions for 

■ keyboard 

■ tape cassette 
• disk 



Description of all CBM BASIC statements 
Optimal programming techniques including 

■ input/output programming 
* file handling 

■ screen editing 

Solutions to programming problems 
CBM capabilities and limitations 



#55-1 $15.00 



Book/Caeeette/Dlek 


Prloe 


Quantity 


Amount 


27-6 6602 Assembly Language Programming 


$18.99 






30-fl PET Personal Computer Guida 


$16 00 






3 1 -4 PET and the IEEE 488 Bui IGPIQI 


$1599 






40-3 Some Common BASIC Programa PET/CBM ad. (book) 


$1499 






26-X Soma Common BASIC Programt PET Caaaatte 


$15.00 






33-0 Soma Common BASIC Programt PET Diak 


$22.60 






38-1 Practical BASIC Program! 


Si & 99 








California raiident tax 

Shipping 

■ I Amount Enclaead 




Shipping: (Shipping for large orders to ba arranged) 
• All foreign ordari $4.00 par book for airmail 







^-^630 



OSBORNE/McGraw-Hill 
630 Bancroft Way, Dept.BII 
Berkeley, California 04710 
(416) 648-2806 • TWX 910-366-7277 



706 



Name:, 



Address:, 
City: 



• $0.45 par book 4th clan in tha U.S. (allow 3-4 wmVi) 

• SO 75 par book UPS in tha U.S. (allow 1 days) 

• $1.60 par book apacial ruih ahipmant by air in tha U.S. 

Caaialtai and Diak: 

a No additional charge in tha U.S 

• $1 .60 aach foreign airmail 



State :_ 
Phone:. 



Dvisa 

Credit Card No.: 



□ Master Card 




Circle 141 on Inquiry card. 



BYTE January 1981 221 



YOU'RE RIGHT! 

KEYED FILE ACCESSING 



is essential to develop effective application 
programs under CP/M® for your 8080/Z80 machine. 
Your on-line, interactive systems demand the 
performance that only a professional keyed file 
accessing package can offer: fast random and 
sequential access to data by key values, on-line 
additions and deletions to your data files, 
elimination of lengthy sorting procedures. 



BUT WHICH ONE? 



Feature 



MICRO B- w The Other One 



• Random Access by Key 


YES 


YES 


• Wild Card Search 


YES 


YES 


• Key-Sequential Access 


YES 


YES 


• Multiple Keys 


YES 


YES 


• Automatic Space 






Reclamation 


YES 


YES 


• Eliminate Overflow Files 


YES 


NO 


• Maximum Number of Entries 


65,535' 


10,000 


• Eliminate Index File 






Reorganization 


YES 


NO 


• Guaranteed Optimal Index 






File Structure 


YES 


NO 


• Maximum Disk Accesses To 






Reach Any of 10.000 Entries 


3 


? 


• Duplicate Key Values 


YES 2 


NO 



'32.767 for the source code versions 
2 Source code versions only. 



IT'S OBVIOUS, GET MICRO B+™! 

And search an index of over 
1 0,000 key values in less than one 
second on a floppy disk system! 



Assembly Language Version ...$260.00 
Specify MICROSOFT. CBASIC", PL/l-80'". S-BASIC" 

Basic Source Code Version ...$195.00 
Specify MICROSOFT Basic or CBASIC" 

Shipping $2 USA / $5 Foreign 
We accept VISA and MASTERCARD 



DEALER INQUIRIES INVITED 



RIrCom 

Making Micro's work like Maxl't 

© 1980 Fair Com 



2606 Johnson Drive 
Columbia, MO 65201 
(314) 445-3304 



CP/M and PL/l-80 are trademarks of Digital Research 
MICROSOFT is a trademark of MICROSOFT. Inc. 
CBASIC Is a trademark of Compiler Systems. Inc. 
S-BASIC is a trademark of Topaz Programming 



will run on a 6809 system with 56 K bytes of program- 
mable memory. The software is available on both 5-inch 
and 8-inch floppy disks, and includes operating system, 
compiler and linker. 

System Checkout 

The power-supply cables and voltages are first checked 
without any other boards installed. Then the mother- 
board is installed, and finally the remaining printed- 
circuit boards. You will need an RS-232C-compatible ter- 
minal connected to the serial-interface card to test for the 
proper message, "S-BUG 1.5-8 K", followed a blinking 
cursor. 

When I performed the checkout, everything appeared 
to be normal until I attached a terminal and noticed that 
the video display consisted of question marks being pro- 
duced much faster than the current data-transfer rate, 
which was 300 bps (bits per second). The SwTPC 
documentation states that if anything is printed, especial- 
ly question marks, the computer is probably working and 
that the problem is probably with the terminal parity, bit 
format, or data-transfer-rate setting. 

I spent a considerable amount of time checking for 
problems and couldn't find anything wrong until I used 
my ohmmeter and observed that the resistance between 
the 300 and 4800 bps lines on the motherboard measured 
about 2 ohms. I immediately suspected a solder bridge 
but was unable to find one I then called in a friend with a 
very accurate ohmmeter. He detected a dip in the 
resistance at the closest pin on the motherboard. Using a 
projector lens, he found two extremely small copper 
bridges that were covered by the green coating on the 
motherboard and were virtually impossible to see with 
the naked eye. After I removed the copper bridges with a 
small knife, the system worked beautifully. 

The moral of this story is that you should be careful to 
check adjacent bus lines on the motherboard both initial- 
ly and after assembly. Doing this will eliminate a lot of 
frustration and wasted time. 



Conclusions 

I'm pleased with the overall quality of the SwTPC 
69/K, and I recommend it to any experienced kit builder. 
One big headache-saver is to check out individual fin- 
ished boards on a working SS-50 or SS-50C system. I 
used a friend's SS-50 computer to test the 8 K-byte pro- 
grammable memory board supplied with the kit. 

If you don't have a means of testing individual boards, 
I strongly suggest the purchase of the 69/A assembled 
and tested system. When you consider the amount of 
time spent assembling and testing the unit, the extra $100 
seems like a bargain. 

SwTPC does have technical services available, but the 
entire computer must be repacked and sent to San An- 
tonio, Texas. Without the proper test equipment, it is dif- 
ficult, if not impossible, to track down specific problems. 

If you purchase factory-assembled boards, SwTPC 
does offer a factory exchange program. Boards can be ex- 
changed for a fixed fee ($40 for the MP-09 processor 
board). All factory-assembled products are included in 
the plan for 6 months, and SwTPC will arrange a service 
contract after the 6-month period. If you're using your 
computer for business, this service is ideal. ■ 



222 January 1981 © BYTE Publications Inc 



Circle 142 on inquiry card. 



CALL FOR PAPERS 

W EUROMICROSl 

SEVENTH SYMPOSIUM ON MICROCOMPUTING 

PARIS, SEPT. 7-10, 1981 



THE SYMPOSIUM 

EUROMICRO 1981 is the seventh annual symposium 
organized by EUROMICRO, the European Associa- 
tion for Microprocessing and Microprogramming. 
Previous annual conferences have been held in Nice, 
Venice, Amsterdam, Munich, Goteborg and London. 
The purpose of this conference is to bring together 
practitioners and theoreticians from industry, govern- 
ment and academia who are interested in all prob- 
lems relating to the underlying concepts and the use 
of microprocessing and microprogramming. 



SUBMISSION OF PAPERS 

Authors are invited to submit original papers on 
recent and novel work in the whole field of 
microprocessing and microprogramming. Solicited 
are all contributions concerning problems of hard- 
ware, firmware, software and applications that are 
typical with respect to systems, development, social 
implications and education. 

Authors should submit six complete copies of their 
papers to the program chairman not later than by 
March 15, 1981. 




EUROMOUSE IN PARIS— CALL FOR MICE 



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Or Contact: Dr. Rodnay Zaks, SYBEX, 2344 Sixth Street, Berkeley, CA 94710 Tel: 415/848-8233 Telex: 336311 



Circle 143 on inquiry card. 



BYTE January 1981 223 



As your introduction to The Library Of 

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224 BYTE January 1981 




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BYTE January 1981 225 



The Picture-Perfect Apple 



Phil Roybal 

1111 Pippin Creek Ct 

San Jose CA 95120 



A picture is worth a thousand 
words. And it was the capability of 
representing information in pictures 
that initially attracted me to the 
Apple II computer. 

But images on a screen can be too 
personal an experience. Often no one 



else sees them. It would be great if 
there were a way to transcribe these 
images so that others could also ap- 
preciate them. There is a way to do it, 
and this article tells how. 

The program discussed here was 
written in Apple (6502) assembly 
language for the Qume Sprint Micro 
3, a daisy-wheel printer with a 16-bit 
parallel interface. The approach is 
quite general in nature; therefore, 
you will find it easy to adapt it to 



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other hardware. 

The high-resolution screen of the 
Apple II is actually a window into the 
memory between decimal addresses 
8192 and 16,383. Anything you see 
there can be printed on paper. This 
means that if you have a graphics 
printer, you needn't go to a lot of 
trouble writing plotting routines for 
it. Those already available in the 
Apple languages and utility programs 
will suffice quite handily. 

This capability can be put to good 
use the next time you need to produce 
a high-quality chart for a presenta- 
tion, or an attention-getting cover for 
a report. You can do the job on the 
same letter-quality printer you used 
to produce the report itself. 

Even if you don't have one of these 
elegant but expensive printers, this 
routine is still useful. Very little 
depends upon either the printer or the 
interface. In fact, the bulk of the 
routine is concerned with decoding 
the high-resolution screen addresses. 
Therefore, you can quickly tailor the 
printer routine to your hardware. 

The High-Resolution Graphics 
Screen 

The Apple graphics screen is a 
tricky beast. If you calculate how 
much memory it should consume, it 
comes out: 

280 dots X 192 lines = 53,760 pixels 

Then consider that there are eight 
colors that can be displayed. This 
means you throw in 3 bits per pixel to 
wind up with: 

53,760 X 3 = 20,160 bytes 
of memory 

Despite this, the screen takes up only 
8192 bytes. How is this done? 

The screen doesn't show every 
color in every location. Only black- 
and-white images take advantage of 
the full resolution of the screen. 
Colors show up in alternate columns 
(green alternates with violet, orange 
with blue, etc). Apple's video cir- 
cuitry and the television set's 
response characteristics combine to 
make the rows of colored dots appear 
to fuse together. Thus, you can draw 
a "solid" horizontal line across the 
screen, regardless of the color you 
plot it in. 



226 January 1981 © BYTE Publications Inc 



While this bit of trickery does save 
memory, it makes analyzing screen 
images rather complex since you have 
to figure out what the color is at any 
given location. Fortunately, since 
most printers produce only black and 
white, the color issue is academic. If a 
dot is there, the printer prints it. The 
end result is that colors appear as less 
dense clusters of dots than solid 
white, providing a shading effect to 
images produced on the printer. 

What causes the most difficulty is 
that the designer of the Apple saved 
himself a logic gate or two through 
the use of rather unorthodox screen 
addressing. As a result, adjacent 
screen rows do not occupy con- 
secutive memory locations. It is the 
decoding of this high-resolution 
screen addressing which accounts for 
a good deal of the complexity of this 
program. The software has to use a 
series of counters to keep track of 
where it is on the screen. (Figure 2 
shows how it works.) 



The high-resolution 

screen of the Apple II Is 

actually a window into 

the memory. 



High-resolution screen addressing 
is easy to understand if it is con- 
sidered as a series of hexadecimal 
rather than decimal numbers. 

As shown in figure 1, the screen is 
divided into three major sets of 
horizontal lines which I call triads. 
Each triad is divided into eight groups 
of horizontal lines called octets. And 
finally, each octet consists of eight 
horizontal lines called fillers. A line 
consists of 280 dots, which are de- 
rived from 40 bytes of memory by us- 
ing the lower 7 bits of each byte. This 
is how it works. 

The triads begin with lines whose 
first bytes (leftmost characters) have 
hexadecimal addresses: 

2000 
2028 
2050 

If you poke Is into these addresses 



while the high-resolution screen is 
black, dots will appear along the left 
margin, evenly dividing the screen 
vertically into thirds. 

Within a triad are octets. The 
octets begin with lines whose first 
bytes are incremented by hexa- 
decimal 80 from the starting address 
of the triad. For example, the first 
triad, which starts at hexadecimal 
2000, has octets beginning with lines 
whose first bytes have hexadecimal 



addresses: 

2000 
2080 
2100 
2180 
2200 
2280 
2300 
2380 

Each ocfef has eight lines within it. 



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January 1981 © BYTE Publications Inc 227 



Circle 144 on inquiry card. 



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These lines start with bytes whose ad- 
dresses go up in increments of hexa- 
decimal 400 from the octet starting 
address. Thus, the first octet of the 
first triad has eight lines in it that start 
with the hexadecimal addresses: 

2000 
2400 
2800 
2C00 
3000 
3400 
3800 
3C00 

This is a bit complex. It helps if you 
work out a table and verify it by pok- 



/* 2000 



ing information into the high-resolu- 
tion screen area. Adapting the pro- 
gram to handle a different printer is 
relatively trivial compared to under- 
standing the address scheme. Thus, 
this algorithm is a good base to build 
on, no matter what hardware you 
use. 

A Tour of the Driver 

The driver routine (see figure 2) 
knows that the screen is contained in 
the memory area between hexa- 
decimal 2000 and 3FFF. Therefore, it 
moves the print head to the left 
margin and then starts with hexa- 
decimal address 2000, in the first 



First 
Triad 



2000 



First 
Octet 



2080 



Line 

Beginning 

Locations 



^ 2028 

r 



Second 
Octet 



Third 
Thru 
Eighth 
Octets 



2028 



2000 
2400 
2800 
2C00 
3000 
3400 
3800 
3C00 
2080 
2480 
2880 
2C80 
3080 
3480 
3880 
3C80 
2100 



2028 



Second 
Triad 



First 
Octet 



Second 
Thru 
Seventh 
Octets 



Eighth 
Octet 



^- 2050 

r 




2050 



Third 
Triad 



V. 



First 
Octet 

Second 
Thru 
Seventh 
Octets 



Eighth 
Octet 




Figure 1: Apple II high-resolution screen-memory addressing. All addresses shown are 
in hexadecimal radix. The screen is divided into three major sets of horizontal lines 
called triads. Each triad is divided into eight groups of horizontal lines called octets. 
Each octet is divided into eight horizontal lines called fillers. Each line uses 40 bytes of 
programmable memory and consists of 280 dots. 



228 January 1981 © BYTE Publications Inc 



Can your 

software pass 

this screen test? 




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BYTE January 1981 229 



Circle 146 on inquiry card. 



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230 January 1981 © BYTE Publications Inc 



triad, first octet, and first filler line, has found a dot. 

Beginning at one end of the first line, In the first case, the complete line is 

it looks at the lower 7 bits of each blank (all zeroes), so the driver issues 

byte until it has scanned (decimal) 40 a line feed. It then picks the next line 

bytes without finding a dot, or until it (in this case, the second filler line in 



f ENTRY J 



INITIALIZE PRINT HEAD POSITION 



TR=OC=FL=BYT=MSK=0 




ADDR = 

$2000+ ($28*TR)+ ($80*0C) + ($400*FL)+ BYT 



DATA=SCREEN (ADDR) 



DATA = DATA AND MASK (MSK) 




YES 



DELTA = ABS(HEAD POS'N- DOT POS N) 



CONSTRUCT HEAD MOTION STRING 



MOVE HEAD 1/60" PER DOT 



UPDATE HEAD POS'N COUNTER 



RAISE RIBBON AND PRINT DOT 



BYT = 



LINE FEED 1/48" 



FL = FL+1 




0C=0C+1 



MSK=MSK+1 




MSK = 




RESET PRINT HEAD 
TO LEFT EDGE 



f RETURN ) 



Figure 2: Flowchart for a program to drive the Qume Sprint Micro 3 plotter to print 
Apple II screen graphics. The shaded boxes indicate hardware-dependent code, 
although the code is very similar for all 16-bit parallel printers. Abbreviations are as 
follows: TR = triad counter; OC = octet counter; FL=filler counter; BYT = filler-line- 
byte counter; and MSK=seven-dot byte mask. 




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Circle 147 on inquiry card. 



BYTE January 1981 231 



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the first octet) and again scans it from 
end to end. This pattern continues (if 
the whole screen is blank) through the 
eight filler lines of each octet, the 
eight octets of each triad, and all 
three triads, until the end of the 
screen is reached. Then the driver 
jumps back to the routine that called 
it. 

When a nonzero bit (a dot on the 
screen) is found, the driver calculates 
the distance from the present print 
head location (normally over the last 
dot printed) to the new dot position. 
It then moves the print head into 
place in a single step (instead of ratch- 
eting along over every dot position). 
When the print head is in place, the 
dot is printed. 

In the driver written here, if at least 
one dot has been printed on a line, the 
next line will be scanned and printed 
from the opposite direction. This pro- 
vides the fastest printing with 
minimum wear and noise under 
average conditions. While this 
scheme is not 100% optimized, it 
does yield very acceptable perfor- 
mance. The determination of scan- 
and head-motion direction adds com- 
plexity to the algorithm without con- 
tributing to the basic capability, so 
this feature is omitted from the flow- 
chart in the interests of clarity. 

The bulk of this program is 
dedicated to screen-address decoding. 
The only section tightly woven about 
the hardware is the output routines. 
These come last in the source code to 
facilitate changing them without 
reassembling the entire driver. They 
assume that you are using a Qume 
printer receiving 16-bit parallel code 
in the format shown in figure 3. If 
you are using another printer and in- 
terface, just write code to send the 
correct control characters to your 
printer hardware. 

Using the Plotter 

The driver was written for a printer 
that provides horizontal resolution of 
120 steps per inch and vertical resolu- 
tion of 48 steps per inch. Two 
horizontal increments are used for 
each screen dot, and one vertical in- 
crement is used for each line. As a 
result, the printer will reproduce the 
high-resolution graphics screen in a 
space about 11.3 by 9.8 cm (4.7 by 4 
inches). This area will be centered on 
a 20.8 cm- (8V2-inch) wide page, and 
will start printing at wherever the 
paper is located at the time the driver 
is called. 

Once you have loaded the driver 
and produced an image in high- 



232 January 1981 © BYTE Publications Inc 



Circle 148 on inquiry card. 



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BYTE January 1981 233 



Circle 150 on inquiry card. 



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resolution page 1, just turn on your 
printer and enter the routine with a 
CALL from BASIC or a G command 
from the monitor. 



7 6 

LOW BYTE 



OUTPUT 
4 3 



— i — I I I f 

ASCII CODES USE BITS 1-7 I 
MOTION CODES USE ALL 8 BITS- 



HIGH BYTE 











1 1 1 

MOTION DISTANCE 
MOST SIGNIFICANT 
DATA BITS (0-4) 
1 1 1 



STROBES: 
-PRINT CHARACTER 
MOVE PRINT CARRIAGE 
Fi D PAPER 

INPUT 



7 
HIGH 


6 
3YTE 


5 


4 


3 


2 


1 






















STATUS FLAGS: 

PRINTER READY 

PLATEN READY 

CARRIAGE (POSITION) READY- 
PRINT HEAD READY 



Getting a Copy of the Driver 

A driver code is rather long for 
publication. In any case, typing it in 
is a masochistic form of entertain- 
ment. To alleviate these problems, I 
have made this code available on 
5-inch floppy disk. The disk includes: 

• object code assembled at hexa- 
decimal location 9000 (for 48 K-byte 
systems), and hexadecimal location 
5000 (for 32 K-byte systems) 

• source code in a text file 

Also included is a version of this code 
adapted for use with Sprint 5 printers 
interfaced through Apple's Serial In- 
terface Card. 

To obtain your copy of this floppy 
disk, send a check for $14.95 (Califor- 
nia residents add 6% sales tax) plus 
$1.00 shipping and handling to Con- 
tech, 1111 Pippin Creek Ct, San Jose 
CA 95120. Ask for the "Picture- 
Perfect Apple" software. ■ 



Figure 3: The form in which the driver 
described in the text communicates with 
the Qume Sprint Micro 3 plotter. A strobe 
consists of a "1" bit in the appropriate 
position, with all other bits "0." If all 
strobes are raised simultaneously, the 
printer is reset and the print carriage 
moves to the left margin. 




Figures 4a, 4b, and 4c: Three examples of Apple II high-resolution graphics transcribed 
by the Qume Sprint Micro 3 plotter, using the driver described in this article. 



234 January 1981 © BYTE Publications Inc 



Poking Data Into the High- 
Resolution Screen Area 

Direct interaction with the 
Apple II high-resolution screen 
memory is an excellent way to 
test addressing schemes and ex- 
plore the structure of Apple 
graphics images. To experiment 
on your own, get into the 
monitor mode (type CALL 
— 155) and display the high- 
resolution screen by typing: 

C050 C054 C057 



resolution screen. To clear it of 
garbage, fill it with Os by typing: 

2000:0 2001 < 2000.3FFEM 

followed by a return. Once you 
have a clean screen, type a hexa- 
decimal address followed by a 
colon and FF. For example: 

2000-.FF 



followed by a return. This will set 
the byte to all Is and will produce 
and hit the Return key. You are a 7-dot-wide line segment at the 
looking at page 1 of the high- appropriate place on the screen. 



4b 




4c 




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January 1981 © BYTE Publications Inc 235 



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236 BYTE January 1981 



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"TRS-80 is a registered trademark of Tandy, Radio Shack. 



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Circle 152 on inquiry card. 



BYTE January W*l 237 



Micrograph 

Part 3: Software and Operation 



E Grady Booch 

4314 Driftwood Dr 

Colorado Springs CO 80907 



Some background on interactive 
computer-graphics systems was pre- 
sented in Part 1. In Part 2, a descrip- 
tion was given of the hardware for a 
low-cost color-graphics display pro- 
cessor, called Micrograph, which in- 
terfaces to a microcomputer as an in- 
telligent peripheral device. In this, the 
third and final part, you will become 
familiar with the software for Micro- 
graph, which implements the display- 
processor instruction set introduced 
in Part 1, and be given instructions 
for operating the system. 

Software Perspective 

Two packages of software are re- 
quired to support Micrograph, as we 
have observed in the generalized 
graphics system in Part 1. The first 
package is the applications software, 
which executes in the host computer. 
This software creates and manipu- 
lates abstractions of images. The 
elements of these images are de- 
scribed to the display processor 
through the instructions in a display 
list. Within the display processor 
itself, there must reside a second soft- 
ware package that converts these in- 
structions into a visible image. 

In Part 1, we described one such in- 
struction set for controlling a color 
raster-scan display processor, and it 
is summarized in table 1, here, in Part 
3. Since emphasis has been on the 
display processor, and since the ap- 
plications software is system specific, 
the remainder of this article will con- 
centrate upon the other package: the 
software internal to the display pro- 
cessor. However, the protocol soft- 
ware in the host computer that is 
needed to carry out communication 
with Micrograph will be described. 



Mnemonic 




Name 


CALL 




Call subroutine 


LCRAM 




Load color memory 


LPIX 




Load pixel 


LREG 




Load register 


LSUB 




Load subroutine 


LSYM 




Load symbol 


MOV 




Move 


RCRAM 




Read color memory 


RET 




Return 


RPIX 




Read pixel 


RREG 




Read register 
Read subroutine 


RSUB 




RSYM 




Read symbol 


SYM 




Display symbol 


VEC 




Draw a vector 


WAIT 




Wait 


Diagnostics are available under XERR. 


Table 1: 


Sum 


mary of graphics 


primitives. 


These 


instructions control 


the graphics-dii 


play processor in 


Micrograph 







Software Description 

The source software for 
Micrograph consists of approxi- 
mately 2400 lines of Z80 assembly- 
language code plus internal com- 
ments. (See listing 2 in Part 1, BYTE, 
November 1980, page 280; listing 1 in 
Part 2, BYTE, December 1980, page 
327; and listing 1, in this issue, page 
240.) This code assembles to approx- 
imately 2.6 K bytes of object code 
and resides in the three system 
EPROMs (erasable programmable 
read-only memories) in the address 
space decimal to 3071. 

The Micrograph software was 
written on a Zilog Development 
System and conforms to the Zilog 
Z80 assembly-language standards. 
Structured programming and step- 



wise refinement were used to develop 
the software. By virtue of these 
techniques, once I had cleared out the 
typos in the source, I required only 
four assemblies to complete the final 
working package. 

Software Structure 

Figure 1 (on page 264) indicates 
that, as a result of stepwise refine- 
ment, the Micrograph software is 
highly structured. The software con- 
sists of one main routine, three driv- 
ing modules, seventeen routines that 
implement the instruction set, twelve 
shared utility routines, and five inter- 
rupt-service routines. These routines 
appear grouped together by their 
class, then alphabetically in the soft- 
ware source listing. 

The routine MAIN drives the entire 
Micrograph software and handles a 
call to the power-up INIT (initializa- 
tion). MAIN then enters an infinite 
loop of instruction fetches (via 
FETCH) and executes (via EXEC). In 
this sequence, Micrograph requests 
an instruction from the host com- 
puter and executes it. PRIMAT is 
then called by EXEC to calculate 
which instruction has been com- 
manded and, in turn, calls the ap- 
propriate routine that processes the 
various options of the instruction. 

These sixteen routines (CALLS 
through WAIT) correspond directly 
to the instruction set in table 1. Since 
the routines execute similar code, 
they may call any of several utility 
routines. These routines include null 
subroutine calls (GUSER and USER), 
routines for communicating with the 
host computer (GETBLK, SENDBK, 
and SENDBY), and some primitive 

Text continued on page 260 



238 January 1981 © BYTE Publications Inc 



COLLECTOR E 



ITION 



I 






M^HtwawLv;... 









VERS 



The Byte Covers shown at left are available as 
Collector Edition Prints. Each full color print is: 

• 1 1" X 14" including a 1 W border. 

• Part of an edition strictly limited to only 100 
prints. 

• Personally inspected, signed and numbered 
by the artist, Robert Tinney. 

• Accompanied by a Certificate of Authenticity. 

• Carefully packed and shipped first class. 

• Priced at $20, plus $3 ($6 overseas) for post- 
age and handling. If Set 1-4 or Set 5-8 is 
ordered, the price for all 4 prints is only $70. 

To order, use the coupon below. Visa or Master- 
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r Please send me the following Collector Edi 
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Qty. Cover Amount 

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#2-Fun and Games $20 

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Listing 1: The final third of the firmware for Micrograph control, written for the Z80 
microprocessor used in the prototype. The first and second portions of the firmware ap- 
peared with Part 1 and Part 2 of this series. 



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**:******:*«« 


¥. S * 3 * 


» « k « * * « s * * * « « * ft *■ k * * x a? * * « 






1867 
















1668 


C.L If 


DETERMIN 


SHOULD BE CLIPPED OR NOT 






1869 


CLIP 


"IRST 


DETERMINES 


THE F 


OINT REFERENCED, THEN 






1870 


COMPARES IT WITH THE CASE. 


SUCCESS IS SET IN THE 






1871 


POINT 


IS NOT CLIPPED. 










1672 
















1873 


CALLS 




NONE 










1874 
















1875 


CALLED 












1876 






PUT 










ie?7 






RPIX 










1878 






LP IX 










1679 
















1680 


REG I J 


TERS 


H 


(TEMPORARY) 






1881 






B 


(CASI 


:> 






1 882 






C 


(SUCCESS) 






1883 






D 


(TEMPORARY) 






1684 






E 


(TEMPORARY) 






1885 






H 


(TEMPORARY) 






1686 






L 


(TEMPORARY) 






1887 






IX 


(INDt 


:x> 






1888 






1Y 


(INDEX) 






1889 
















1690 


1/0 




NONE 










1891 
















1892 


STRUCTU 


GDRO 


(X) 








1893 






GDR1 


(Y) 








1894 






GDR6-13 


(VIEWPORTS) 






1895 






REF 


(REFERENCE) 






1896 












07EF" 


0L01 


1697 


;lips 


LD 


C, 1 




(ASSUME SUCCESS 


7F1. 


DDCB434E 


1898 




B I T 


1 , (IX+REF) 




(POINT TO REFERENCE 


D7F5 


00 


1899 




RET 


N7 




(RETURN IF SET 


07F6 


F5 


1900 




PUSH 


AF 




(SAVE A AND F 


D7F7 


FDE5 


1901 




PUSH 


1Y 




(SAVE IY 


07F9 


E5 


1902 




PUSH 


HI- 




(SAVE H AND L 


07FA 


[)5 


1903 




PUSH 


DE 




(SAVE D AND E 


07FB 


0E00 


1904 




LD 


CO 




(CLEAR SUCCESS 


07FD 


FD218610 


1905 




LD 


I Y, STRUCT +GDR6 


(LOAD REFERENCE START 


0801 


DDCB4346 


1906 




BIT 


0, (IX+REF) 




(TEST REFERENCE 


0605 


2804 


1907 




JR 


Z.CLIPO 




(JUMP IF NOT SET 


0807 


FD218A10 


1908 




LD 


IY.STRUCT+GDR10 


(LOAD REFERENCE START 


obob 


FD6E00 


1909 


;lipo: 


LD 


L, (IY+0) 




(LOAD LEFT X 


OBOE 


2600 


1910 




LD 


H,0 




(CLEAR H 


0610 


Cf.D9 


1911 




SET 


3,C 




(SET BIT 3 


0812 


DD5E0 


1912 




LD 


E, (IX+GDRO 




(GET X 


0615 


1600 


1913 




LD 


0,0 




(CLEAR D 


0817 


AF 


1914 




XOR 


A 




(CLEAR CARRY 


0818 


ED52 


1915 




SBC 


HL.DE 




(SUBTRACT 


081A 


FA2108 


1916 




JP 


I'I,CLIP1 




(JUMP IF MINUS 


081D 


2802 


1917 




JR 


Z, CI I PI 




(JUMP IF ZERO 


08 1F 


CB99 


1.918 




RES 


3,C 




(SET BIT 3 


0621 


FD6E02 


1919 


:lipi : 


LD 


L, ( IY-12) 




(LOAD RIGHT X 


0824 


2600 


1920 




LD 


H,0 




(CLEAR H 


OS 24 


CBD1 


1921 




SET 


2 7 c; 




(SET BIT 2 


08 28 


DD5E00 


1922 




LD 


E, (IX + GDRO 




(GET X 


082B 


1600 


1923 




LD 


D , 




(CLEAR D 


082D 


AF 


1924 




XOR 


A 




(CLEAR CARRY 


062E 


E052 


1925 




BBC 


HL.DE 




(SUBTRACT 


U830 


FA3508 


1926 




JP 


M.CLIP2 




(JUMP IF MINUS 


0633 


CE91 


1927 




RES 


2,C 




(RESET BIT 2 


0835 


FD6E01 


1928 


:LIP2: 


LD 


l , ( t y n ) 




(LOAD LEFT Y 


0636 


2600 


1929 




LD 


H,u 




(CLEAR H 


083A 


CBC9 


1930 




SET 


1,C 




(SET BIT 1 


063C 


DD5E01 


1 931 




LD 


E, (IXl GDR1 




(GUI Y 


083F 


1600 


1932 




LD 


D , 1] 




(CLEAR D 


0841 


AF 


1933 




XOR 


A 




(CLEAR CARRY 


0842 


ED52 


1934 




SBC 


HL.DE 




(SUBTRACT 


0844 


FA4B08 


1935 




JP 


M.CLIP3 




(JUMP IF MINUS 


8 4 7 


280 2 


.1936 




JR 


Z, EL IP 3 




(JUMP IF ZERO 


0849 


CB89 


1937 




RES 


1 ,C 




(SET BIT 1 


08 48 


F DAE 3 


1938 


:lip3i 


LD 


L. ( IY+3) 




(LOAD RIGHT Y 


084E 


2600 


1939 




LD 


H,0 




(CLEAR H 


0850 


CBC1 


1940 




SET 


0,C 




(SET BIT 


0652 


DD5E01 


1941 




LD 


E. (IX+GDR1 ) 




(GET Y 


0855 


1600 


1942 




LD 


DrO 




(CLEAR D 


0857 


AF 


1943 




XOR 


A 




(CLEAR CARRY 


0858 


ED52 


1944 




SBC 


HL.DE 




(SUBTRACT 


065A 


FA5F08 


1945 




JP 


M.CLIP4 




(JUMP IF MINUS 


08SD 


CB81 


1946 




RFS 


Q.C 




(CLEAR BIT 


085F 


79 


1947 


:LIP4: 


LD 


ft,C 




(GET C 


0840 


0E00 


1948 




LD 


CO 




(CLEAR SUCCESS 


0862 


CB46 


1949 




BIT 


1 ,B 




(TEST CASE 


0864 


2014 


1950 




JR 


NZ.CLIP6 




(JUMP IF SET 


0666 


CB40 


1951 




B I T 


0,B 




(TEST CASE 


0868 


2006 


1952 




JR 


NZ, CLIPS 




(JUMP IF NOT SET 



Listing 1 continued on page 242 



240 January 1981 © BYTE Publications Inc 



H 



N 
C. 



CQIYIPLITRQNICS 

• ••EVERYTHING FOR YOUR TRS-80 ••• 

TRS-SO Is a trademark of ihr Radio Shac k Division of Tandy Corporation 

1980 INCOME TAX PAC 

Completely Revised • Latest Tax Tables •Fully Tested • Complete Manual and Documentation 
• • The New Version Of The Income Tax Pacs Are Full Of Error Catching Codes • • 

• * Making It Impossible To Make An Error • * 
— Follow The Simple Step By Step Procedure That Makes Tax Preparation Simple — 



r 



* INCOME TAX PAC A 

FOR LEVEL II 16K 

• DOES FORM 1040 and 1040A 

• SCHEDULE A ITEMIZED DEDUCTIONS 

• SCHEDULE S INTEREST and DIVIDENDS 

• OUTPUT TO VIDEO DISPLAY 

• SCHEDULE C TAX COMPUTATION 



_L. 



• INCOME TAX PAC B 

FOR LEVEL II with or without Printer, Cassette or Disk. Has all features 
of Income Tax A PLUS, 

• WORKS WITH LINE PRINTER 

• FORMATS FORM 1040 and 1040A FOR TRACTOR FEED FORMS 

• SCHEDULE C INCOME FROM A PERSONALLY OWNED BUSINESS 

• FORM 2106 EMPLOYEE BUSINESS EXPENSE 



n 



FORM 1040 (LONG FORM) 

FORM 1040A (SHORT FORM) 

FORM 2106 EMPLOYEE BUSINESS EXPENSE 

FORM 2440 DISABILITY INCOME EXCLUSION 

FORM 2441 CREDIT FOR CHILD AND DEPENDENT CARE EXPENSES 

FORMS 3903 MOVING EXPENSE ADJUSTMENT 

FORM 4797 SUPPLEMENTAL SCHEDULE OF GAINS AND LOSSES 



* * PROFESSIONAL * * 
INCOME TAX PAC C 



• SCHEDULE A ITEMIZED DEDUCTIONS 

• SCHEDULE B INTEREST AND DIVIDENDS 

• SCHEDULE C PROFIT (OR LOSS) FROM BUSINESS OR PROFESSION 

• SCHEDULE D CAPITAL GAINS AND LOSSES 

• SCHEDULE E SUPPLEMENTAL INCOME SCHEDULE 

• SCHEDULE G INCOME AVERAGING 

• SCHEDULES R & RP-CREDIT FOR THE ELDERLY 



FOR MODEL I (32K) or MODEL II (64K) 

WITH 1 OR MORE 

DISK DRIVES 

kLL SPECIFICATIONS SUBJECT TO CHANGE 



• SCHEDULE SE-COMPUTATION OF SOCIAL SECURITY SELF-EMPLOYMENT TAX 

• SCHEDULE TC TAX COMPUTATION 

• OUTPUT TO VIDEO OR LINE PRINTER 

• FORMATS FOR TRACTOR FEED OR INDIVIDUAL FORM FEED PRINTERS 

• AUTOMATIC MEMORY STORAGE FOR INCOME TAX PREPARERS 

• INSTANT LINE CHANGE 

• BUILT IN ERROR CHECKING 



•CQMPJTRQNICS 



■ v \A T *-«*vUi"* .a 



50 N. PASCACK ROAD 
SPRING VALLEY, NEW YORK 10977 

PLEASE SEND ME: 

□ INCOME TAX PAC A (S19 95) 

D INCOME TAX PAC B ($49.95) 

D PROFESSIONAL INCOME TAX PAC C (S99 95) 

O MODEL II PROFESSIONAL INCOME TAX PAC C (S199.95) 



NEW TOLL-FREE 

ORDER LINE 

(OUTSIDE OF NY. STATE) 

(800) 431-2818 



* A COMPLETE LINE OF NELCO TAX FORMS 

ARE AVAILABLE 

• INDIVIDUAL FEDERAL and STATE FORMS 

• 2 OR MORE PART FORMS 

• TRACTOR FEED FORMS 

• PLASTIC OVERLAYS 



■k All orders processed within 24-Hours 
•k 30-Day money back guarantee on all Software 
• Add $2.00 for shipping in UPS Areas 
• Add $3.00 for COD. or NON-UPS Areas 
• Add $4.00 outside U.S.A., Canada & Mexico 



CREDIT CARD NUMBER 
SIGNATURE 



.EXP DATE 



NAME. 



STREET. 



CITY. 



.STATE. 



.ZIP. 



Circle 154 on Inquiry card. 




HOUR 
24 ORDER 
LINE 

(914) 425-1535 



BYTE January 1981 241 



Circle 155 on inquiry card. 



MTI stocks 'em 
for faster deli vc 


all] 


No hidden charges. Prices include delivery. 


VISA and MasterCard orders accepted. 


VIDEO TERMINALS 






1695 




2295 








. 


ADM-31 (2 page buffer) 


« 


ADM-42 (8 page buffer avail.) 


» 




825 


1420 (dumb terminal) 


895 


1421 (Consul 580 & ADM-3A comp.).... 


895 




1045 


1510 (buffered) 


1145 




1395 


1552 (VT-52 compatible) 


1350 


300 BAUD TELEPRINTERS 




LA34-DA DECwriter IV 


1045 

1295 

..1085 


LA34-AA DECwriter IV 






1225 


Diablo 630 RO 


2295 


Diablo 1640 RO 


3085 


Diablo 1640 KSR 


3285 


Diablo 1650 RO 


3185 


Diablo 1650 KSR 


3385 


Tl 743 (portable) 


1190 
1585 


Tl 745 (portable/built-in coupler) 


Tl 763 (portable/bubble memory) 


2690 


Tl 765 (port/bubble mem/b-i coupler) 


2895 


600 BAUD TELEPRINTERS 


Tl 825 RO impact 


1565 


Tl 825 KSR impact 


1645 


Tl 825 RO Pkg. 


1750 


Tl 825 KSR Pkg 


1R95 


1200 BAUD TELEPRINTERS 


LA120-AA DECwriter III (forms pkg.l 


. 2410 


LA180 DECprinter I 


. 2195 


Tl 783 (portable) 


1745 
2395 




Tl 787 (port/internal modem) 


. 2845 


Tl 810 RO impact 


1800 


Tl 810 RO Pkg 


. 2047 


Tl 820 KSR impact 


. 1895 


Tl 820 KSR Pkg 


1995 


Tl 820 RO 


1895 
. 2047 


Tl 820 RO Pkg 


2400 BAUD 




Dataproducts M200 (2400 baud) . .. 


.2595 


DATAPRODUCTS LINE PRINTERS 


B300 (300LPM band) 


. 5535 


B600 (600LPM band) 


6861 


2230 (300LPM drum) 


7723 


2260 (600LPM drum) 


9614 
12655 


2290 (900LPM drum) 


ACOUSTIC COUPLERS 




A/J A242-A (300 baud orig.) 


242 
315 


A/J 247 (300 baud orig.) 


A/J AD342 (300 baud orig./ans.l 


395 


A/J 1234 (Vadic compatible) 


895 
695 


A/J 1245 1300/1200 Bell comp.) 


MODEMS 


GDC 103A3 (300 baud Bell) 


395 

565 

.. 850 


GDC 202S/T (1200 baud Bell) 


GDC 212-A (300/1200 baud Bell) 


A/J 1256 (Vadic compatible) 


825 
MS 


CASSETTE STORAGE SYSTE 




...1050 


Techtran817 Istore/for/speed up) 


1295 


Techtran 818 (editing) 


. 1795 




2295 


MFE 5000 (editing) 


. 1495 


FLOPPY DISK SYSTEMS 




Techtran 950 (store/forward) 


. 1395 


Techtran 951 (editing) 


1995 


"Please call for quote. 




Applications Specialists & Distributors 


Great Neck, New York/Cleveland 


Ohio. 


N.Y.: 516/482 3500 & 212/895-7177 


k 800/645-8018 Ohio: 216/464 6688 



Listing 


1 continued: 












086A 


FEDA 


1953 


CP 


10 




JTEST IF 10 


086C 


2820 


1954 


JR 


Z, CLIPS 




;JUMP IF EQUAL 


086E 


1822 


1955 


JR 


CLIP9 




JJUMP AROUND 


0870 


FE08 


1956 CLIPS: CP 


8 




JTEST IF 8 


0872 


2B1A 


1957 


JR 


Z.CLIPS 




;JUMP IF SO 


0874 


FE0B 


1958 


CP 


11 




;TEST IF 11 


0B76 


2816 


1959 


JR 


Z, CLIPS 




;JUMP IF SO 


0878 


1818 


1960 


JR 


CLIP9 




;JUMP AROUND 


087A 


CB40 


1961 CLIP6: BIT 


0,B 




JTEST BIT 


087C 


200A 


1962 


JR 


NZ,CLIP7 




;JUMP IF SET 


oe7E 


FE02 


1963 


CP 


r> 




JTEST IF 2 


0880 


280C 


1964 


JR 


Z, CLIPS 




JJUMP IF SO 


0882 


FE0E 


1965 


CP 


14 




JTEST IF 14 


0884 


2808 


1966 


JR 


Z, CLIPS 




JJUMP IF SO 


0886 


180A 


1967 


JR 


CLIP9 




JJUMP AROUND 


0888 


FE05 


1968 CLIP7: CP 


5 




JTEST IF 5 


088A 


2002 


1969 


JR 


NZ.CLIP8 




JJUMP IF NOT SO 


088C 


1804 


1970 


JR 


CLIP9 




J JUMP AROUND 


08SE 


0E01 


1971 CLIPS: LD 


C, 1 




JSET SUCCESS 


0890 


1802 


1972 


JR 


CLIP10 




JJUMP AROUND 


0692 


0E00 


1973 CLIP9: LD 


CO 




JCLEAR SUCCESS 


0894 


Dl 


1974 CLIP10: POP 


DE 




JRESTORE D AND E 


0895 


El 


1975 


POP 


HL 




JRESTORE H AND L 


0896 


FDE1 


1976 


POP 


IY 




JRESTORE IY 


0898 


Fl 


1977 


POP 


AF 




JRESTORE AF 


0899 


C9 


1978 
1979 


RET 






J RETURN 






1980 


GETBLK *** 


********** 


********* 


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






1981 














1982 


GETBLK READS B BYTES 


OF DATA 


AND PLACES THE DATA 






1983 


STARTING AT HL. 










1984 














1985 


CALLS 


FETCH 










1986 














1987 


CALLED BY 


LCRAM 










1988 




LSUB 










1989 




LSYM 










1990 














1991 


REGISTERS 


A 


(DATA) 








1992 




B 


(COUNT) 








1993 




H 


(POINTER) 






1994 




L 


(POINTER) 






1995 














1996 


I/O 


NONE 










1997 














1998 


STRUCTURES 


NONE 










1999 










089ft 


CDED01 


2000 


3ETBLK: CALL 


FETCH 




JCALL FETCH 


089D 


77 


2001 


LD 


<HL),A 




J SAVE THE DATA 


089E 


23 


2002 


TNC 


HL 




J INCREMENT THE POINTER 


039F 


05 


2003 


DEC 


B 




JDECREMENT THE COUNT 


0SA0 


20FB 


2004 


JR 


NZ, GETBLK 




JJUMP IF NOT DONE 


08A2 


C9 


200S 
2006 


RET 






J RE TURN 






2007 


GUSER **** 


********** 


********* 


**•::******************** 






20U8 














2009 


GUBER IS THE DEFAULT 


GRAPHICS 


SUBROUTINE WHICH IS 






2010 


THE DUMMY 


CALL FORM 


THE PRIMITIVE CALL. GUSER SlflPL 






201 1 


RETURNS. 












2012 














2013 


CALLS 


NONE 










2014 














2015 


CALLED BY 


CALLS 










2016 














2017 


REGISTERS 


NONE 










2018 














2019 


I/O 


NONE 










2020 














2021 


STRUCTURES 


NONE 










2022 










08A3 


80 


2023 
2024 


iUSER: DEFB 


128 




JRETURN FROM GRAPHICS 






2025 


PEEK ***** 


********** 


********* 


*********************** T 






2026 














2027 


PEEK READS 


DATA FROM 


A PIXEL. 


PEEK FIRST SETS A READ 






2028 


FLAG, CALLS PIXEL, THEN RETURNS. PEEK EXPECTS THE 






2029 


PIXEL TO BE AT XY. THE COLOR 


IS RETURNED IN ft. 






2030 














2031 


CALLS 


PIXEL 










2032 














2033 


CALLED BY 


RPIX 










2034 














2035 


REGISTERS 


A 


(COLOR 


RETURN) 






2036 




C 


(READ FLAG) 






2037 














2038 


I/O 


NONE 










2039 














2040 


STRUCTURES 


NONE 










2041 










08A4 


0E01 


2042 1 


•EEK: LD 


C, 1 




JSET REftO FLAG 


08A6 


CDAA08 


2043 


CALL 


PIXEL 




JGET THE DATA 


08A9 


C9 


2044 
2045 


RET 






J RETURN 






2046 


PIXEL **** 


********** 


********* 


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






2047 














2048 


PIXEL MAPS 


THE USER 


I00RDINATE DATA TO THE PHYSICAL 






2049 


SYSTEM. THIS IS PERHAPS THE MOST COMPLEX ROUTINE IN 






205D 


THE FIRMWARE, AND IS 


THE ONLY 


ROUTINE THAT MUST 



Listing 1 continued on page 244 



242 January 1981 © BYTE Publications Inc 



DEALERS: By now you know that it takes 



SOFTWARE 

TO SELL 

COMPUTERS 



and International Micro Systems can provide you with the largest selection of quality business 
applications ever developed for the microcomputer industry. 

If you are just looking for a G.L., A/P, and Payroll, you can find them in a dozen ads in this 
magazine. But thers's a much bigger market for micros out there than that. Where can you find a 
fully interfaced Wholesale/Retail Distribution System? How about Manufacturing Inventory 
Control including Production Scheduling & Control. See that one anywhere else? Maybe your 
market is Medical/Dental and IMS has the full systems there too. You can't sell computers 
without software and IMS has the finest selection of software available foryou. Each system has 
been developed by the IMS professional staff and we support what we sell. 

But thats not all. International Micro Systems has the strongest dealer marketing plan in the 
industry. With our 

$ 245 Dealer Demo System. 

we put all the software shown below in your office or store ready to demo to your prospects and 
we include the promotional material and our unique video sales presentation to help you move 
systems. Give us a call or drop us a card and let us show you what selling business systems 
should be all about. 



Financial Systems 

GL. A/P, A/R 

Payroll 

Cash Receipts/Disb. 

Job Costing 

Mailing List Mgmt. 
Medical/Dental 

Office.Scheduler 

Patient Billing 4 AVR 

Insurance Forms 
Governmental/Educational 

Student Record Keeping 

and Scheduling 

Fund Accounting 



Wholesale Distribution System 

Purchasing & Receiving 

Inventory Control 

Invoicing & Receivables 

Salesman Comm. Reporting 

Backorder Management 
Manufacturing Inventory Control 

Finished Goods Inventory Mgmt. 

Parts Inventory Mgmt. 

Parts Purchasing & Receiving 

Bill of Material 

Production Scheduling 



INTERNATIONAL 
IICRO 





S 



YSTEMS 



For details on our demo special, contact us at: 
8425 Quivira Road, Lenexa, Kansas 66215 
Phone: (913) 888-8330 



Circle 156 on inquiry card. 



BYTE January 1981 243 



Circle 157 on inquiry card . 

SUPERBRAIN 




32K or 64K (Double or Quad Density units 
available). Uses two Z-80 CPU's. Commercial- 
type terminal with 12" monitor. Dual double 
density minifloppies. Over 350 kilobytes of 
storage (twice that with quad density drives). 
Two serial RS232 ports, I/O ports standard. 
Expandable with optional S-100 S-100 inter- 
face. Comes with CP/M™ 2.2 operating sys- 
tem. MiniMicroMart includes BASIC inter- 
preter and can supply a wide range of CP/M 
Development and Application software. 

w/32K Double Density, List $2995 . $2685 

w/64K Double Density, List $3345 $2883 

w/64K Quad Density, List $3995 $3595 

64K Special Quad Version $3395 



INTERSYSTEMS 

formerly ITHACA AUDIO 




DPS-1, List $1795 

Call for Price! 

The new Series II CPU Board features a 4 MHz 
Z-80A CPU and a full-feature front panel. 20- 
slot actively terminated motherboard, with 25 
amp power supply (50/60 Hz operation, incl. 
68cfmfan). 

COMPLETE SYSTEM with InterSystem 64K 
RAM, I/O Board w/priority interrupt and 
double density disk controller board. Full 1-year 
warranty, List $3595 



HEWLETT-PACKARD 

HP-85A 




F.O.B. shipping point. All prices subject to change and all 
offers subject to withdrawal without notice. Advertised prices 
are for prepaid orders. Credit card and C.O.D. 2% higher. 
C.O.D. may require deposit. 

- WRITE FOR FREE CATALOG - 

MiniMicroMart 

1618 James Street 
Syracuse, IMY 13203 (315) 422-4467 



Listing 1 continued: 



OBAA 
08AC 
OBAD 
08AE 

OSAF 
03B2 

Dee. 4 
uae.i 

08BS 

081} A 
0BBD 
08BF 
08C2 

08 CS 

oecs 

DSC 9 

oacft 

C8CC 
0BCE 

08D1 
08D3 

0SD5 
08D7 
08D9 
D8DB 

08DD 
06DF' 
08E1 
0BE4 
OSES 
D8EB 
08EA 

obec; 

08EE 
0BF0 
08F2 
08F3 
08F4 
08F5 
08F7 
08F9 
D8FB 
08FD 
Q8FF 
0901 
0903 
090S 
0907 
0909 
090B 
090C 
090D 
0V0F 
0910 
0911 
0912 
0911 
0916 
0918 
091A 
09 1.C 

09 IE 
09 If 
0920 
0921 
0922 
0923 
0921 



FDE5 

E5 

05 

F5 

DD7E0E 

E6E0 

FE00 

280 D 

Ft CO 

CA4209 

F EE0 

CAB709 

C39000 

DD7EQ1 

2F 

67 

CB3C 

CB3C 

DD6E00 

CB3C 

CB1D 

CB3C 

CB1D 

CB3C 

CB1D 

CB3C 

CB1D 

110020 

19 

DD7E00 

E60C 

CB3F 

CB3F 

CB41 

2B1E 

IF 

Fl 

7E 

CB41 

2301 

CB27 

CB27 

CB4 9 

2808 

CB27 

CB27 

CB27 

CBS 7 

E6C0 

Dl 

El 

FDE1 

C9 

4F 

f 1 

163F 

E6C0 

CB41 

2E0A 

CB3F 

CB3F 

FS 

7 A 

OF 

01 

57 

F 1 

CB49 



2051 

2052 

2053 

2054 

2055 

2056 

2057 

205B 

2059 

2060 

2061 

2062 

2063 

2064 

2065 

2066 

2067 

2068 

2069 

2070 

2071 

2072 

2073 

2074 

2075 

2076 

2077 

2073 

2079 

2080 

2081 

2082 

2083 

2084 

2085 

2086 

21.187 

2088 

2089 

2090 

2091 

2092 

2093 

2094 

2095 

2096 

2097 

2098 

23?'/ 

2100 

2101 

2102 

2103 

2104 

2105 

2106 

2107 

2108 

2109 

21.10 

2111 

2112 

2113 

2114 

2115 

2116 

2 1 1 7 

2118 

2119 

2120 

21.21 

2122 

2123 

2124 

2125 

2126 

2127 

2128 PIXEL 

2129 

2130 

2131 

2132 

2133 PIXEL 

2134 

2135 

2136 

2137 

2138 

2139 

2140 

2 1 4 1 

214 2 

2143 

2144 

2145 

2146 

21.47 PIXEL 



BE MODIFIED IF SYSTEM II IS USED. PIXEL FIRST 
DETERMINES WHAT DISPLAY DENSITY IF USED. AND IF THE 
OPERATION IS READ OR WRITE. THE PHYSICAL ADDRESS 
OF THE PIXEL IS DETERMINED, THEN THE BIT ADDRESS IS 
MAPPED OUT. PIXEL DEALS WITH THE PIXEL AT XY , THE 
READ FLAG IN REGISTER C, AND EXPECTS/RETURNS THE 
COLOR IN REGISTER A. 



CALLS 



CALLED BY 



REGISTERS 



I/O 
STRUCTURES 



IXELOs I. 



PIXEL1 I 



NONE 

POKE 
PEEK 

A 

c 

D 
E 

H 
L 

IX 
IY 

NONE 

GDRO 
BDR1 
GDR14 



(COLOR, FLAGS) 

(FLAGS, TEMPORARY) 

(TEMPORARY) 

(TEMPORARY) 

(POINTER) 

(POINTER) 

( INDEX) 

(INDEX) 



(X) 
(Y) 
(DISPLAY FORMAT) 



PUSH 

PUSH 

PUSH 

PUSH 

LD 

AND 

CP 

JR 

CP 

JP 

Cf 

JP 

JP 

D 
EPI 
LD 

SRI. 
SRL 
LD 
SRL 
RR 
SRL 
RR 
SRL 
RR 
SRL 
RR 
LD 
ADD 
LD 
AND 
SRL 
SRL. 
B I T 
JR 
LD 
POP 
LD 
BIT 
JR 
SLA 
SLA 
BIT 
JR 
SLA 
SLA 
BLA 
SLA 
AND 
POP- 
POP 
POP 
RET 
LD 
POP 
LD 
AND 
BIT 
JR 
SRL 
SRL 
PUSH 
LD 

RRCA 
RRCA 
LD 
POP 
BIT 



REFRESH RAM 

IY 
HL 
DE 
AF 
A. (IX+GDRM) 

liioaonoi} 

u 

Z, PIXELJ) 

11 000 00 Of. 

Z, PIXEL* 

11100000EJ 

Z.PIXEI...C 

XERR 

A, < IXK3DR1 ) 

H,A 

H 

H 

I , ( IX+ODRO) 

H 

L 

H 

L 

H 

L 

H 

L 

DE.RBOTTOM 

HLiDE 

A, < IX + GDRO) 

00001 100B 

A 

A 

O.C 

2, PIXELS 

C,A 

AF 

A, <HL> 

0,0 

Z.PIXEL1 

ft 

A 

1 ,C 

Z,PIXEL2 

A 

A 

A 

A 

11000000B 

DE 

HL 

IY 

C,A 

AF 

D, 001 11 11 IB 

11000000B 

0,0 

7.PIXEL4 

A 

A 

AF 

A,D 



D,A 

AF 

1,C 



(SAVE IY 

(SAVE HL 

(SAVE DE 

(SAVE AF 

;glt display i ormat 
(MASK all but type 

(64 X 64 ? 

(JUMP IF SO 

;128 X 128 ? 

(JUMP IF 80 

125* X 192 ■■■ 

(JUMP ':-' 80 

! ERROR OTHERWISE 

(BET Y 

: COMPLEMENT 

(LOAD H 

! SHIFT 

; SHIFT 

iLOAD X 

; SHIFT 

! SHI FT 

(SHIFT 

; SHIF1 

; SHI FT 

; SHIF'I 

(SHIFT 

(SHIFT 

(LOAD BASE ADDRESS 

(ADO OFFSET 

(GET X 

(MASK ALL BUT 2 BITE; 

(SHIFT 

(SHIFT 

(CHECK READ FLAI3 

[JUMP IF NOT SET 

(LOAD C 

(RESTORE A 

(GET PIXEL 

(CHECK LSB 

(JUMP IF ZERO 

(SHIFT A 

(SHIFT A 

(TEST NEXT BIT 

(JUMP IF ZERO 

(SHIFT 

(SHIFT 

(SHIFT 

(SHIFT 

(MASK ALL ELSE 

(RESTORE DE 

(RESTORE HL 

(RESTORE IY 

(RETURN 

(SAVE DATA 

(RESTORE COLOR 

(LOAD A MASK 

(MASK COLOR 

(TEST READ FLAG 

(JUMP IF NOT SET 

(SHIFT 

(SHIFT 

(SAVE AF 

(GET THE MASK 

(ROTATE RIGHT 

[ROTATE RIGHT 

[RESTORE THE MASK 

[ RESTORE AF 

(TEST LSB 

Listing 1 continued on page 246 




32K Board Pictured Above 



Why Not the Best? 

From The Dynamic RAM Company. 



2MHz 


4MHz 


16K-$249 


$259 


32K-S375 


$395 


48K— $500 


$530 


64K— $625 


$665 



We have now been shipping 
our 2MHz dynamic RAM boards 
for over two years. Hundreds of 
4MHz boards have been going 
out every month since early 
1979. Our reliability is proven in 
the thousands of systems which 
contain our board. Many quality- 
minded systems houses across 
the country and overseas are 
using our boards for their 
equipment. 

Our prices still beat all. 
Despite rising 1 6K memory chip 
prices (at least from reputable 
suppliers), Central Data continues 
to give you the best buy in 
memory today. Nobody offers a 
board with a capacity of 64K, 
assembled, tested, and guaranteed 
for a full year at the price we do. 

Circle 158 on Inquiry card. 



Deselect around PROMs. Our 

boards have the important deselect 
feature which lets you overlap any 
fixed memory in your system with 
no interference. 

Our features make the board 
easily used and expanded. You 
address our boards on 1 6K 
boundaries with mini-jumps (small 
shorting plugs that slide over wire- 
wrap pins) near the top of the 
board for easy access. If you want 
to expand your board after you 
have purchased it, all that you 
need to do is add memory. We 
can supply you with expansion 
packages ($150-2MHz, 
$160-4MHz) which include eight 
RAMs that you can depend on as 
well as two mini-jumps for 
addressing. And of course, our 
board never generates wait states. 

Low power consumption keeps 
your computer running cool and 
reliable. The total power 
consumption of our 1 6K board is 
typically less than 4 watts (+8V @ 
300ma, + 1 6V @ 1 50ma and 



-16V @ 20ma). Boards with 
additional memory typically 
increase power consumption only 
1 watt per 1 6K! 

Standard S-100 Interface. Our 
board is designed to interface with 
any standard S-100 CPU. All of 
the timing of the board is 
independent of the processor chip, 
and the board is set up for 
different processors by changing 
two plugs on the board. 

Call or write us today. That will 
guarantee a fast response with 
more information on the board. Or 
make an order — you'll probably 
have the board in two weeks! If 
you're interested, also ask for a 
catalog on our Z8000 16-bit 
processor board designed for the 
MULTIBUS. All of these products 
are available to your local dealer, 
also. 

Central Data Corporation, 713 
Edgebrook Drive, PO Box 2530, 
Station A, Champaign, IL 61820. 
(217) 359-8010 



Central Data 

BYTE January 1981 



245 



NO FRILLS! 

NO GIMMICKS! 

JUST GREAT 

DISCOUNTS 

MAIL ORDER ONLY 



ATARI 800 

Personal Computer 

System $79900 

NORTHSTAR 

Horizon II 32K 234900 

Horizon II Quad 279900 

Horizon II 64K 299900 

Horizon Quad 64K 339900 

TELEVIDE0 

912 74900 

920 79900 

HAZELTINE 

1420 79500 

1500 84900 

1510 104900 

1520 122900 

0KIDATA 

Microline80 69900 

S0R0C Technology 

iq 120 69900 

iq 140 99900 

CR0MEMC0 

System 3 569500 

Z2H 799500 

INTERTEC 

Superbrain32K 249500 

Superbrain64K 279500 

DECwriter IV 

LA34 97900 



TEXAS INSTRUMENT 

810 Multi Copy 

Impact Printer 149900 



We'll meet or beat any advertised prices! 



Most Hems in slock lor immediate delivery. 
Factory sealed canons Full manulacturer s guarantee 

DATA DISCOUNT CENTER 

Box 100 135-53 Northern Blvd., Flushing, NY. 11354 

Visa • Masier Chaige • N Y S , residents add Sales Tax 
Shipping F B. NY. 

Phone Orders Call 212-465-6609 



Listing 1 continued: 



0926 


2010 


2118 


JR 


Z, PIXELS 


[JUMP IF ZERO 


0928 


CB3F 


2119 


SRL 


A 


(SHIFT 


092A 


CB3F 


2150 


SRL 


ft 


ISHIF1 


092C 


CB3F 


2151 


SRL 


A 


; SHIFT 


092E 


CB3F 


2152 


BRL 


A 


; SHI FT 


0930 


F5 


21.53 


PUSH 


AF 


(SAVE AF 


0931 


7 A 


2151 


LD 


ft.D 


(SET THE MASK 


0932 


OF 


2155 


RRCA 




[ROTATE RIGHT 


0933 


OF 


2156 


P. RCA 




[ROTATE RIGHT 


0931 


OF 


2157 


RRCA 




; ROTATE RIGHT 


935 


OF 


2158 


RRCA 




! ROT ATE RIGHT 


0936 


5 7 


2159 


LD 


D,A 


;GET THE MASK 


093"/ 


Fl 


2160 


POP 


AF 


(RESTORE AF 


0938 


IF 


2161 PIXELS: LD 


C,A 


[SAVE MASK 


939 


7E 


2162 


LD 


A. (HL) 


;get data 


093A 


A2 


2163 


AND 


D 


(MASK THE old 


093B 


Bl 


2161 


OR 


C 


;and data 


093C 


77 


2165 


LD 


(HL) ,A 


[SAVE PIXEL 


093D 


Dl 


2166 


POP 


DE 


(RESTORE DE 


093E 


El 


2167 


POP 


HL 


(RESTORE HL 


093F 


FDE1 


2168 


POP 


1Y 


(RESTORE IY 


0941 


C9 


2169 


RET 




(RETURN 


0912 


DD7E01 


2170 PIXEL6: LD 


A, ( IXhGDRI) 


(LOAD Y 


0915 


2F 


2171 


CPL 




[COMPLEMENT 


0916 


67 


2172 


LD 


H,A 


(LOAD Fl 


0917 


CB3C 


2173 


SRL 


H 


(SHIFT 


0919 


DD6E00 


2171 


LD 


L. CIX+BDRO) 


(LOAD X 


091C 


CB3C 


2175 


SRL 


H 


[SHIFT 


091E 


CB1D 


2176 


RR 


L 


(SHIFT 


0950 


CB3C 


2177 


SRL 


H 


(SHIFT 


0952 


CB1D 


2178 


RR 


L 


(SHIFT 


0951 


CB3C 


2179 


SRL 


H 


(SHIFT 


0956 


CB1D 


2180 


RR 


L 


(SHIFT 


0958 


110028 


2181 


LD 


DE.RBOTTOM+2018 


(LOAD BASE ADDRESS 


95B 


19 


2182 


ADD 


HL.DE 


(ADD OFFSET 


095C 


DD7E00 


2183 


LD 


A, (IX+GDRO) 


(GET X 


095F 


E606 


2181 


AND 


000001 10B 


[MASK ALL BUT 2 BITS 


0961 


CB3F 


2185 


SRL 


A 


(SHIFT 


0963 


CB11 


2186 


BIT 


o.c 


(TEST LSB 


0965 


281E 


2187 


JR 


Z.PIXEL9 


(JUMP IF NOT SET 


0967 


IF 


2ise 


LD 


C,A 


(SAVE A 


0968 


Fl 


2189 


POP 


AF 


(RESTORE A 


0969 


7E 


2190 


LD 


A, (HL) 


(GET PIXEL DATA 


096A 


CB11 


2191 


BIT 


OrC 


(TEST NEXT BIT 


096C 


2801 


2192 


JR 


Z.PIXEL7 


(JUMP IF NOT SET 


096E 


CB27 


2193 


SLA 


A 


(SHIFT 


0970 


CB27 


2191 


SLA 


A 


[SHIFT 


0972 


CB19 


2195 PIXEL7: BIT 


IrC 


(TEST NEXT BIT 


0971 


2808 


2196 


JR 


Z.PIXEL8 


(JUMP IF NOT SET 


0976 


CB27 


2197 


SLA 


A 


[SHIFT 


0978 


CB27 


2198 


SLA 


A 


[SHIFT 


097A 


CB27 


2199 


SLA 


A 


[SHIFT 


097C 


CB27 


2200 


SLA 


A 


(SHIFT 


097E 


E6C0 


2201 PIXEL8: AND 


11000000B 


[AND ALL ELSE 


0980 


Dl 


2202 


POP 


DE 


[RESTORE DE 


0981 


El 


2203 


POP 


HL 


[RESTORE HL 


0982 


FDE1 


2201 


POP 


1Y 


[RESTORE IY 


0981 


C9 


2205 


RET 




[RETURN 


0985 


1F 


2206 PIXEL9: LD 


C,A 


[RESTORE A 


0986 


Fl 


2207 


POP 


AF 


[RESTORE STACK 


0987 


163F 


2208 


LD 


D, 001 11 HIE 


(GET THE MASK 


0989 


E6C0 


2209 


AND 


11000000B 


(MASK ALL ELSE 


09 BE 


CB11 


2210 


BIT 


O.C 


[CHECK LSB 


093D 


2S0A 


2211 


JR 


Z, PIXELA 


[JUMP IF ZERO 


098F 


CB3F 


2212 


SRL 


A 


[SHIFT 


0991 


CB3F 


2213 


SRL 


A 


[SHIFT 


0993 


F5 


2211 


PUSH 


AF 


[SAVE AF 


0991 


7A 


2215 


LD 


A,D 


(GET THE MASK 


0995 


OF 


2216 


RRCA 




[R0TA1E RIGHT 


0996 


OF 


2217 


RRCA 




[ROTATE RIGHT 


0997 


57 


221B 


LD 


D,A 


[RESTORE THE MASK 


0998 


Fl 


2219 


POP 


AF 


[RESTORE THE MASK 


0999 


CB19 


2220 PIXELA: BIT 


1 ,C 


[CHECK NEXT BIT 


099B 


2810 


2221 


JR 


Z, PIXELS 


[JUMP IF ZERO 


099D 


CB3F 


2222 


SRL. 


A 


[SHIFT 


099F 


CB3F 


2223 


SRL 


A 


[SHIFT 


9 A 1 


CB3F 


2221 


BRL 


A 


[SHIFT 


09A3 


CB3F 


22^5 


SRL 


A 


(SHIFT 


09A5 


F5 


2226 


PUSH 


AF 


(SAVE. AF 


09A6 


,'n 


2227 


LD 


A,D 


[GET THE MASK 


09A7 


OF 


2228 


RRCA 




[ROTATE RIGHT 


09A8 


OF 


2229 


RRCA 




[ROTATE RIGHT 


09A9 


OF 


2230 


RRCA 




[ROTATE RIGHT 


09AA 


OF 


2231 


RRCA 




[ROTATE RIGHT 


09AE: 


57 


2232 


LD 


D, A 


[RE1 THE MASK 


09AC 


Fl 


2233 


POP 


AF 


[RESTORE AF 


09AD 


1F 


2231 PIXELS! LD 


C, A 


[SAVE A 


09AE 


7E 


2235 


LD 


A, (HL) 


(GET PIXEL DATA 


D9AF 


A 2 


2236 


AND 


D 


(MASK THE OLD 


09B0 


Bl 


2237 


OR 


C 


(OR WITH C 


09B1 


77 


2238 


LD 


(HL) ,A 


(SAVE PIXEL 


09B2 


Dl 


2239 


POP 


DE 


[RESTORE DE 


09B3 


El 


2210 


POP 


HL 


[RESTORE HL 


09B1 


FDE1 


2211 


POP 


IY 


[RESTORE IY 


09B6 


C9 


2212 


RET 




[RETURN 


09B7 


DD7E01 


2213 PIXFLC: LD 


A, (IXi-GDRl ) 


[MOVE Y TO A 


09BA 


2F 


2211 


CPL 




[COMPLEMENT 



Listing 1 continued on page 248 



246 January 1981 © BYTE Publications Inc 



<F,V 



.Threaded Interpretive 

Languages 




R. G. Loeliger 



Threaded languages (such as FORTH) are an exciting new class of languages. They are compact 
and fast, giving the speed of assembly language with the programming ease of BASIC, and com- 
bine features found in no other programming languages. An increasing number of people are 
using them, but few know much about how they work. Is a threaded language interpreted or 
compiled? How much memory overhead does it require? Just what is an "inner interpreter?" 
Threaded Interpretive Languages, by R. G. Loeliger, concentrates on the development of an 
interactive, extensible language with specific routines for the ZILOG Z80 microprocessor. With 
the core interpreter, assembler, and data type defining words covered in the text, it is possible to 
design and implement programs for almost any application imaginable. Since the language itself 
is highly segmented into very short routines, it is easy to design equivalent routines for different 
processors and produce an equivalent threaded interpretive language for other development sys- 
tems. If you are interested in learning how to write better FORTH programs or you want to design 
your own powerful, but low-cost, threaded language specific to your needs, this book is for you. 



linil 



This and other BYTE/McGraw-Hill 
books are available from BYTE 
Books or your local computer store. 

Please send 



. copies of Threaded Interpretive Languages 



ISBN 0-07-038360-X 
Price $18.95 



B1 



Name 



Title 



Company 



Street 



City 



Stale/Province 



Code 



Call TOLL FREE: 800-258-5420 
or Mail To: 



Bill 

k;ii\s 7: " 



Peterborough, Nil 0345K 



I Check enclosed in the amount of $ 

Bill Visa Bill Master Charge 

Card No. 

Exp. Date 

Add 75ff per book to cover postage and handling. 
Please remit in U.S. funds or draw on a U.S. Bank. 



Circle 160 on inquiry card. 



W* 



Z8QOO 



The System X800O MICRO-MINI"* based on 
the 16-bit Zilog Z8000 processor is available 
for Immediate delivery. 

FEATURES (partial list) 

• Zilog Z8000 CPU 

• Intel Multibus compatible 

• Unique memory management system 
allows up to 16 megabytes of memory 

• Optional 951 1 arithmetic processor 

• 8-level vectored + non-maskable interrupts 

• Two programable timers 

• On-board monitor ROM option 

• Full "Multimaster" capabilities allow multiple 
processors and/or DMA devices on the 
same bus 

• Flexible and/or hard disk controller 

• Powerful disk-based operating system 

• Memory boards: 16K, 32K, 48K, 64K, 96K, 
128K 

• 15-slot backplane 

• Heavy-duty switching power supply 

• Industrial quality throughout 

Prices start from $998. System discounts. 
Call for prices on complete custom systems. 

SYSTEM X9020 

(CPU Manual $19.95) 




$ 4195 



The SUPER-MICRO'" 
READY TO RUN 



SYSTEM FEATURES (partial Hit) 
Paical MICROENGINE" X9000 

• 16biiP-codeCPU 

• 64K bytes RAM/Full DMA 

• Floppy disk controller (SS or DS) 

• Floating point hardware (IEEE standard) 

• System software with enhancements 

• 2 serial, 2 parallel ports 

• Pascal compiler. text editors, file manager, 

CPU & memory diagnostics, symbolic Pascal debugger. 
linker, utilities and more. 
Floppy Disk Drives (2) 

• 1M combined memory 

• Double density, single sided 

• Standard B" diskettes 

• 6 ms track to track 




$900* 

With CPU 



MODEL X-920 

DISPLAY/EDIT TERMINAL 

•LIMITED TIMF. cash price. 1 0% DOWN guarantees 

priority. Master Charge & VISA cards accepted. 
System discounts 

ADM3A+ plus RG graphics (512x256). ..$1995 

NEC Spinwriter 5510 or 5530 w/trac 2895 

Anadex DP-9500 printer (60dpi) 1595 

X-912 CRT (less 18 function keys) 799 

P-E 550 CRT ("Bantam") 740 

Siemens standard 8" drive (ss/sd-dd) .... 399 



312 684-3183 



^^" COMPUTEX 

J^L \ Microcomputer Sy»t ems \ 

^^\ \ 5710 Drexel, Chlcigo, IL 60637 



Listing 1 continued: 



09BB 


67 


2245 




LD 


H,A 


SAVE IN H 


9BC 


DD6E00 


2246 




LD 


L, (IX+GDRO) 


GET X 


09BF 


CB3C 


2247 




SRL 


H 


SHIFT H 


09C1 


CB1D 


2248 




RR 


L 


SHIFT L 


09C3 


CB3C 


2249 




SRL 


H 


SHIFT H 


D9C5 


CB1D 


2250 




RR 


L 


SHIFT L 


09C7 


CB3C 


2251 




SRL 


H 


SHIFT H 


09C9 


CB1D 


2252 




RR 


L 


SHIFT L 


09CB 


110018 


2253 




LD 


DE,RE0TT0M-2048 


POINT TO BOTTOM 


09CE 


19 


2254 




ADD 


HL. ,DE 


ADD OFFSET 


09CF 


DD7E00 


2255 




LD 


A, (IX+GDRO) 


GET X 


09D2 


E607 


2256 




AND 


00000111B 


MASK A 


0904 


CB41 


2257 




BIT 


0,C 


TEST LSB 


09D6 


2824 


2258 




JR 


2, PIXELS 


TEST FOR READ 


09D8 


4F 


2259 




LD 


C,A 


LOAD C 


09D9 


Fl 


2260 




POP 


AF 


RESTORE A 


09DA 


7E 


2261 




LD 


A,(HL> 


GET PIXEL 


09DB 


CB41 


2262 




BIT 


0,C 


•TEST LSB 


09DD 


2802 


2263 




JR 


Z.PIXELD 


SJUMP AROUND SHIFT 


09DF 


CB27 


2264 




SLA 


A 


;SHIFT A 


09E1 


CB49 


2265 


=TXEL0: 


BIT 


1,C 


;test next bit 


09E3 


2804 


2266 




JR 


Z.PIXELE 


JJUMP AROUND SHIFT 


09E5 


CB27 


2267 




SLA 


A 


JSHIFT A 


09E7 


CB27 


2268 




SLA 


A 


;SHIFT A 


09E9 


CB51 


2269 


••IXELE; 


BIT 


2,C 


;TEST NEXT BIT 


09EB 


2808 


2270 




JR 


Z.PIXELF 


;JU«P AROUND SHIFT 


09ED 


CB27 


2271 




SLA 


A 


(SHIFT A 


09EF 


CB27 


2272 




SLA 


A 


; SHIFT A 


09F1 


CB27 


2273 




SLA 


A 


JSHIFT A 


09F3 


CB27 


2274 




SLA 


A 


; SHI FT A 


09F5 


E680 


2275 


E'lXELF: 


AND 


100000O0B 


(MASK ALL OTHERS 


09F7 


Dl 


2276 




POP 


DE 


; RESTORE DE 


09F8 


El 


2277 




POP 


HL 


RESTORE HL 


09F9 


FDE1 


2278 




POP 


IY 


(RESTORE IY 


09FB 


C9 


2279 




RET 




; RETURN 


09FC 


4F 


2280 


='IXELG: 


LD 


C,A 


■SAVE DATA 


09FD 


Fl 


2281 




POP 


AF 


;GET COLOR 


09FE 


167F 


228^ 




LD 


d. om hub 


[LOAD THE MASK 


oaoo 


E680 


228 3 




AND 


loooooaoB 


•MASK ALL EL8E 


DA02 


CB41 


2284 




BIT 


o,c 


■TEST LSB 


0A04 


2807 


2285 




JR 


Z.PIXELH 


JUMP AROUND SHIFT 


0A06 


CB3F 


22E6 




SRL 


A 


SHIFT 


0A08 


F5 


2287 




PUSH 


AF 


SAVE AF 


0A09 


7A 


2288 




LD 


A,D 


GET THE MASK 


0AC1A 


OF 


2289 




RRCA 




ROTATE RIGH1 


0A0B 


57 


2290 




LD 


D,A 


GET THE MASK 


0A0C 


Fl 


2291 




POP 


AF 


RESTORE AF 


0AOD 


0B4 9 


2292 


"•1.XELH: 


BIT 


1,C 


TEST NEXT BIT 


0A0F 


280A 


2293 




JR 


Z,PIXELI 


JUMP AROUND SH.TI- r 


0A11 


CB3F 


2294 




SRL 


A 


SHIFT 


UAli 


CB.5I-" 


2295 




SRL 


A 


SHIFT 


D a i :, 


F 5 


2296 




PUSH 


AF 


SAVE AF 


0A16 


7rt 


2297 




LD 


A»D 


GE ' 1 HE MASK 


0A1V 


or 


2296 




RRCA 




ROTATE R1GK1 


0A18 


OF 


2299 




RRCA 




ROTATE RIGHT 


0A1V 


57 


2300 




LD 


D , A 


GET THE MASK 


0A1A 


Fl 


2301 




POP 


AF 


RESTORE AF 


0A1B 


CB51 


2302 


'■1XLL.1 : 


B 1 T 


2,C 


TES'I NEXT Bl"! 


GA1D 


2810 


2303 




JR 


Z, PIXEL J 


JUMP AROUND SH ' F r 


0A1F 


CB3F 


2304 




SRL 


A 


SHIFT 


0A2t 


CB3F 


2305 




SRL 


A 


SHTFT 


0A23 


CB3F 


2306 




SRL 


A 


SHIFT 


0A2S 


CB3F 


2307 




SRL 


A 


SHIFT 


0A27 


F5 


2308 




PUSH 


AF 


SAVF, AF 


0A28 


7 A 


2309 




LD 


A , D 


GET THE MASK 


0A29 


OF 


2310 




RRCA 




ROTATE RIGHT 


DA2A 


OF 


2311 




RRCA 




ROTATE RIGHT 


0A2B 


OF 


2312 




RRCA 




ROTATE RIGHT 


0A2C 


(IF 


2313 




RRCA 




ROTATE RIGHT 


0A2D 


57 


2314 




LD 


D,A 


GET HIE MASK 


0A2E 


F 1 


2315 




POP 


AF 


RESTORE AF 


0A2F 


4F 


2316 


'IXELJ: 


LD 


C, A 


SAVE A 


0A3Q 


7E 


2317 




LD 


A , ( HL ) 


GET PIXEL 


0A31 


A2 


2318 




AND 


D 


MASK THE OLD PARI 


0A32 


Bl 


2319 




OR 


C ! 


OR DATA 


0A33 


77 


232D 




LD 


(HL),A 


SAVE PIXEL 


0A34 


Dl 


2321 




POP 


DE ! 


RESTORE DE 


0A35 


El 


2322 




POP 


HL 


RESTORE HL 


0A36 


FDE1 


2323 




POP 


IY i 


RESTORE IY 


0A38 


09 


2324 
2325 
2326 
2327 
2328 




RET 




RETURN 






POKE 


««««*****««***«**«******** 


***********«**«*«« 






POKE 


WRITES DATA TO THE PIXEL t 


T XY. POKE SETS A 






2329 


WRITE 


FLAG 


THEN CALLS PIXEL. TF 


E COLOR DATA IS 






2330 


EXPECTE TER A. 








2331 














2332 


CALLS 




PIXEL 








2333 














2334 


CALLED 


LPIX 








2335 






PUT 








2336 














2337 














2338 


REGIS 


TERS 


C (WRITE FL 


AG) 






2339 














2340 


I/O 




NONE 








2341 











Listing 1 continued on page 250 



248 January 1981 © BYTE Publications Inc 



SIRIUS 80+ 

High Performance 

Low Cost Floppy Add-Ons ! 

The SIRIUS SYSTEMS 80+ Series of Floppy 
Disk add-ons are designed to provide un- 
matched versatility and performance for your 
TRS-80* . Consisting of four different add- 
ons, there is a 80+ Series Floppy Disk Drive to 
meet your needs. 

COMMON CHARACTERISTICS 

■ 5ms track-to-track access lime 

■ Auto-Eject 
m 180 day WARRANTY 

■ Exceptional speed stability - 11l2°k 

■ Single/Double Density operation 

■ Mix any or all 80+ Series ontbeSS 
Standard cable 

SPECIFIC CHARACTERISTICS 
The SIRIUS 80+1 -a single sided, 40 track 
Drive. Offering 5 more tracks than the Radio 
Shack model, it cost $120 less. Formatted 
data storage is 102K/204K Bytes Single/ 
Double Density. 

SIRIUS 80+1 $379.95 

The SIRIUS 80+2 is a dual sided, 80 track (40 
per side) Disk Drive. It appears to the TRS-80* 
as TWO 40 track drives yet COST LESS THAN 
HALF THE PRICEI Even greater savings result 
since data is recorded on both sides of the 
media instead of only a single side. This unit 
may require the SS Standard cable. Formatted 
data storage is 204K/408K Bytes Single/Double 

tensity. 

SIRIUS 80+2 $449.95 

The SIRIUS 80+3 - a single sided, 80 track 
Drive. Offering 2'/3 times the storage of a 
standard Radio Shack Disk Drive, the 80+3 
greatly reduces the need for diskettes corre- 
spondingly. Additionally, because of the in- 
creased storage and faster track-to-track 
access time, the 80+3 allows tremendously 
increased throughput for disk based pro- 




grams! The 80+3 includes SIRIUS's TRAKS- 
PATCH on diskette (for use with 96 tpi drives) . 
Formatted data storage is 204K/408K Bytes 
Single/Double Density. 
SIRIUS 80+3 $499.95 

The SIRIUS 80+4 -a dual sided. 160 track (BO 
per side) 5'/<" monster! The ultimate in state- 
of-the-art 5V4" Floppy Disk Technology, the 
80+4 is seen by the TRS-80* as two single 
sided disk drives. Thus, in terms of capacity, 
one 80+4 is equivalent to 4% standard Radio 
Shack drives — at a savings of over 73% (not 
to mention diskettes!!!), (with a double den- 
sity converter the available memory is huge!) 
The 80+4 (a 96 tpi drive) includes TRAKS- 
PATCH on diskette and may require the SS 
Standard cable. Formatted storage is 408K/ 
816K Bytes Single/Double Density. 
SIRIUS 80+4 $649.95 

All 80+ Series Floppy Disk add-ons operate at 
5ms track-to-track but are Expansion Interface 
limited to 12ms for the TRS-80* 
*TRS-80© ol Tandy Corp. 

ACCESSORIES 

SS Standard 2 Drive Cable $29.95 

NEWDOS/80-Sophisticaled Operating System 
for the TRS-BO* from Apparat $149.95 



Save up to 10% with these SIRIUS Packages 



NEWDOS/80, SIRIUS 80+3, and Two Drive Cable 

NEWDOS/80, SIRIUS 80+4. and Two Drive Cable 

NEWDOS/80, Two (2) SIRIUS 80+3's, Two Drive Cable 
NEWDOS/80, Two (2) SIRIUS 80+4's, Two Drive Cable 



$624.95 

$749.95 

$1080.95 

$1349.95 




PRIAM 

Hard Disks 
Now Available 
from SIRIUS 
SYSTEMS! 



PRIAM'S high-performance, low-cost Winchester disc drives speed up throughput and expand data storage 
from 20 megabytes to 154 megabytes. And a single controller can be used to operate 14-inch-disc drives with 
capacities of 33, 66, or 154 megabytes or floppy-disc-size drives holding 20 and 34 megabytes. So it's easy to 
move up in capacity, or reduce package size, without changing important system elements or performance. 



I Fast, Linear Voice Coil Positioning 
I 10 ms track-to-track positioning 
I Fully servoed head positioning 
I Dedicated servo track