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Vol . 5 MO . 2: 




Journal 



. ""Devoted Exclusively To The Atari Computer User" 



IN THIS ISSUE. . . 









ANTIC'S C.E.S. ATARI PREUIEN 
BANK-SMITCHING CARTRIDGES 



XMODEM PROTOCOL 








REVIEWS 

MODEMS AND AMODEM 



LOGO DISPLAY LIST INTERRUPTS 



.AND MORE! 




Published by the Michigan Atari Computer Enthusiasts 



F-IRESIIDE CHAT 



CEISETERS 



Well^ here I am feeling happy about my Atarit 
I read the report on CES printed elsewhere in 
this Journal, and was really impressed* I 
can't wait to get my hands on a 3 1/2" 500k 
disk drive! And for only $100!!! 

One bad thing about Atari is that they don't 
advertise* The Vice President of Atari, James 
Copeland, was on WXYT Radio's "Tech Talk" a 
couple weeks ago and I got in as the first, and 
only, caller to question him* Advertising is 
what I asked him about* It's sad, but Atari 
feels it's not their place to advertise* They 
feel it's their job to manufacture and the 
retailers' (Sears, Toys~R-Us, etc*) to 
advertise* The only way to push our product is 
to do it ourselves* Maybe, just maybe, we 
should start a big letter-writing campaign and 
let the powers that be know how we feel* It 
makes me mad, as a proud Atari owner, to 
watch TV and see 3 or 4 Commodore ads, a 
couple of Apple ads, and nothing about Atari* 
What good is it to make a super machine and 
not tell anyone? 

Anyhow, enough rambling from me* There is 
enough good stuff to read in here this month 
without my going on and on* Remember, write 
to Atari!! 

Kirk 



The MACE Journal is published monthly by the 
Michigan Atari Computer Enthusiasts* Unless 
otherwise noted, material published in the 
Journal is in the public domain and may be 
reproduced for private or user group use 
providing proper credit is given* 

Submissions to the Journal can be mailed to 
the PO Box, uploaded to the MACE BBSs or any 
officer's BBS, or uploaded directly to the 
editor at 646-4455* Where possible, 
submissions should include a disk or tape file 
in AtariWriter or similar format and a working 
copy of the program* Specify format for screen 
dumps (AtariArtist, Koalapad, etc*)* Authors 
whose submissions are published will receive 
a certificate good for a free disk or tape from 
the MACE library* 



Antic magazine lists the following Atari 
service centers in Michigan? 

The Family Computer Center 

3895 W* 12 Mile Rd* 

Berkley 

(313) 543-0520 

ABL Electronic Service, Inc* 
32 E* 14 Mile Rd* 
Madison Heights 
(313) 588-6663 

Solid State Service 
548 Shattuck Rd* 
Saginaw 
(517) 752-0606 

Future Directions 
1520 N* Van Dyke 
Bad Axe 
(517) 269-7211 

Chase Transistor Service 
521 Leonard St* NW 
Grand Rapids 
(616) 454-9000 

Remember that with Atari's new service 
policy, equipment under warranty must be 
returned to the place of purchase for 
replacement* After the 90-day warranty 
period, repairs are at the expense of the 
owner* 



TS YOXTR TIME XJI=^? 



Please take a moment to look at the mailing 
label on the back cover of this Journal* Are 
your name and address correct? And what 
about that date in the upper right-hand 
corner? That's the expiration date of your 
MACE membership* If it's coming up soon, 
plan to renew at the next MACE meeting, or 
fill out the membership form on the inside 
back cover and send it in* 



EXXEIMIDED BASXC 



reference: qref, xref, size 
control: @D,eEiex 



INTRODUCTION 

Extended BASIC is a programmer's aid package 
«#liich adds twelve useful cximmands to BASIC « 
The commands are direct mode commands and 
function as if they were included in the BASIC 
cartridget There are DOS-relatedf editing» 
reference and control commands* 

SYSTEM REQUIREMENTS 

Atari 400/800 

(Translator disk required for XL machines) 
32K RAM 

Atari 810 disk drive or equivalent 
Atari BASIC language cartridge 
System printer (Optional) 

LOADING EXTENDjD BASIC 

!• Turn the comfHifaMr off* 

2f Insert the BASIC cartridge* 

3f Turn on disk drive #1« 

4« When the busy light ga#s oiit# insert the 
Extended BASIC diskette* 

5# Turn on the computer and TV* The 
program Mill load into memory and start 
automatically* 

6* After the system boots the top line on 
the screen should say« 
Extefuted BASIC I #0 

You may now edit an0 RUN BASIC programs 
normally* 

USING EXTENDED BASIC 

• Extended BASIC commands must be entered in 
direct mode and there can be only one command 
per line* All direct mode input to BASIC is 
converted to upper-case normal video* The 
cyily text that is not oinverted is the text 
within double quotes* 

COJylJyLAJSLIDS 

The following commands comprise the Extended 
BASIC program* 

editing: RENUMBER, DELETE, REPLACE, 
MARGIN 

DOS utilities: directory, lock, 

UNLOCK, ERASE, RENAME 



RENUMBER (RENJ: Takes the program text 
and renuinbers it axxording to the parameters 
entered* Extended BASIC will renumber the 
program even if the program contains variable 
branching ivid unreferencsed line numberst 
Variable branching and unreferenced line 
numbers are displayed during the renumbering 
process* 

format: renumber CSTRTJ CNEWJ C,INC3 
COUTPUT] 

Parameter explanation: 

STRT - Starting line nu^r (default is the 
first line of the program) 

NEW - New starting line number (default is 
the starting liQi^iiiip^er) 

INC * Increment lietween line numbers 
(default is 10) 

OUTPUT - Device to which ttm error fUgii 
will be printed* VaJid aukput deviam mn Etf St 
and P: (default is E:) 
Examples: 

RENUMBER 10r»20f "Pi" 
The program will be renumbered starting at 10 
with increments of 20} the. error flags will go 
to ttm syi^tem printer* 

REN» ff5 

If the furst progrMi Imm was 100 then the 

program will be renumbered starting at 100 
with increm^s of 5} the error flags will go to 
the screen* 

RENt 40P0##"E:" 
The pri^am wiU now start at 10(X) with 
increments of 10} the error flags will go to the 
screen* 

RENUMBER ERROR FLAGS 
The error flags are printed whenever a 
variable branch or an unre^enmaKl line number 
is encountered* The types of error flags are 
as follows: 

V/1000 - |he. V indica^ a variable branch 
and 1000 is^ tfie lira number where it occurs* 

#740000/ 1000 - The # indicates an 
unreferenced line number^ the 40000 is the 
unkrKHm line number and the 1000 is the line 
number where it occurs* 



—3— 



DELETE (DEL*): Deletes all line numbers 
mthin the two parameterst 

format: delete strt cendj 

Pmmmimrmx^lmationi 

STRT - Starting line number 

END - Ending line number (default is the 
starting line number) 
Examples* 

DELETE 10,100 
LinM 40 through 100 are deleted* 

DEL* 20 
Line 20 is deleted* 

REPLACE (REPL*)J Replaces a variable name 
with a n#w variable name* 

format: REPLACE "OLD-VAR", "NEW-VAR" 

Parameter explanation! 

OLD-VAR - Old variable name* This must be 
a valid variable name* 

NEW~VAR - New variable name* This must 
be a valid variable name and unique* 
If OLD-VAR is a string thi^n NEH-VAR must 
be a strinc;. The same applies to array names* 
The format for variable names is described in 
the BASIC Reference Manual* 
Examples* ^ 

REPLACE "A$"/'B$" 
All ocourenoB^ of A$ are replacesd with B$ and 
M is f«mSMs4 from the variable name table* 

REPL* "ARRAY(","DARRY(" 
All occurences of ARRAY( are replaced with 
DARRAY( and ARRAY( is removed from the 
variable name table* 

REPL* "COUNTER","LCOUNT" 
All occurences of counter are replaced with 
IMQVmT and CK^UKTER is removed from the 
variable name table* 

REPLACE ERROR FLAGS 

22 - Old variable name not found* 

23 - New variable name already exists* 

24 - Invalid variable name* 

MARGIN iHAR.n Automatically sets the left 
and right iriargihsi 

format: margin £LEFT3£,RIGHT3 



Parameter explanation* 
LEFT - Left margin} this must be greater 

than or equal to 0 and less than 40 (default is 
2) 

RIGHT - Right margin* this must be greater 
than or equal to 0 and less than 40 (default is 
39) 

Examples* 
MAR* 0,39 

The margins are set to the extreme left and 
right edges of the screen* — " 
MAR* 

The margins are set as they are after system 
reset* 

OOS XJXII-IXIES 

Five DOS commands are included in the 
Extended BASIC pr€9gram« They will allcw the 
programmer limited file maintenance* Note! 
The DOS command has been disabled to give 
the programmer the most free memory^ and 
because DUP will overwrite Extended BASIC'S 
memory* If you need to go to DOS the 
following commands will get you there* 

DOS 

DIRECTORY (DI*): Prints the directory of a 
disk to the output device* 

format: DIRECTORY CDRIVE#3C,0UTPUT] 
Parameter explanation* 

DRIVEt - Disk drive number for the ^ired 
directory (default is drive #1) 

OUTPUT - Device to which the printed 
output is to go* Valid devices are E*» S* and P« 
(default EJ) 

Examples* 

DIR* ' 
The directory of drive #1 is displayed on the 
screen* 

DIR*/'PJ" 

The directory of drive #1 is printed on the 
system printer* ' 

DIRECTORY 2 
The directory of drive #2 is displayed on the 
screen* 



LOCK, UNLOCK (UNL*) AMD ERASE (ERAt)J 

These commands lock# unlock and erase (delete) 
files on a disk* 

FORMAT? LOCK "DCN]:FILESPECC» EXT]" 
This command will lock the selects file» or 

files that meet wildcard spedficationst 

FORMAT! UNLOCK "DCNllFILESPECitEXTJ" 
This command will unlock the s#lectetf fite» or 
files that meet wildcard specifications* 

FORMATl ERASE "DCMJIFIU^PECttEXir 

This command will erase the selected file, or 
files that meet wildnrd Jpedf iintions* . ^ 

Parameter explanation* 
N - Drive number (default is drive #1) 
FXl^FEC - Filename & optional extension 

RENAME (RENA«)« Renames a file with a new 

format: RENAME "D£N3JQLDNAME*EXT, 
NEMNAMEtEXT*' 

Parameter explanation* 
N ^ I}riv# mimtier Utef aidt is drive *1) 

OLDNAME - The old filename 
liEi^NAME - The new filename 




QREF (QR*)} QUICK REFERENCE gives a dump 
of the variable name tablet Nhen the screen 
fills upf press any Imf^ ^o^mnhmm^^^ 
screen* 

FORMAT} <3REF [OUTPUT J ^ 

Parameter explanation! 

OUTPUT - Device to which the printed 
output is to go* Valid devices are E!> S! and Pt 
(default device is E! 

XREF (XR*)! CROSS REFERENCE gives a cross 
reference of all variables used in the program* 
It wiU prmt the variable f)Mie aiKt jUI 
occurences of it* 

FORMAT! XREF COUTPUT3 

Parameter explanation! 



OUTPUT 0e¥ic3e to which the printed 

output is to go* Valid devices are EU S* and P! 
(default device is E!) 

Example* 
XREF "S!" 

A$ 

2/100 1/110 10/1000 

A* is the variable name and in the second line 
the 2/100 indicates 2 occurences in line 
nurrdber 100« The 1/110 indicates 1 oaxnrenGe 
in line llOt and so on* 

SIZE: (SI»n Tlos Gmmmnd mqiMtmm no 

parameters* It will return the number of 
variables in the program* the pr^ram length 
and the amount of free spaoNmnaining* 

KJSMAT! SIZE. _ 

OUTPUT FORMAT! 

Number of variables / Program size / Free 
memory remaining 

Example! 
SIZE 

12/500/28500 

This indicates that there mre 12 variables in 

the variable name table* The program length 
is 500 bytes and there are 28500 bytes of 
meirary remainii^* 

eDt Temporarily DISABLES Extended BASIC* 
It should be used before running any program 
that c3on tains any input statements^ 

FORMAT! 0D 

QEr ENABLES Extended BA^€» It is the 

power-up mode* 

FORMAT! @E 

ex; TERMINATE^ Extended BASIC in case it 
is n#t reared w if more memory is neected* A 

"NEW" command should be executed after @X 
to reclaim memoryt 

FORMAT! ex 



REFERENCE CARD 

(mm ABBREV« PMMHETERS 



DniNG 



REMMBER 


REN. 


CSTRT]C»NEU]C»BiC3C»0UTPUT] 


DELETE 


DEL. 


STRTCEM)] 


REPLACE 


REFl, 


"OLD-VAR","ffiH-VAR" 




MAR* 


£LEFT3C,RIGHT3 


ISUTIiniES 




DIRECTORY DI« 


[DRIVE#][, OUTPUT] 


LOCK 


LOCK 


"DCN]JFILESPECC.EXT3" 


INjBCK 


UNL. 


"OCN3JFILESPECC.EXT3" 


ERASE 


ERA. 


"DCN3JFILES>ECC.EXT]" 


RENAME 


REM. 


"D[N]:aLDNM£.EXT,NE}«ME.EXT 



REFERENCE COMhWBS 

QREF OR* aumni - - 

XREF XR. tOUTPUlf ^ 
■ST7F SI» 



CONTROL COHHANDS 

8D TENPflRMOLr DISttLE EXTENDED BASIC 

BE RENABLE EXTENDED BASIC 

iX TERMINATES EXTENDED BASIC ' 



CREATING THE FILE 

Type in the BASIC loader program exactly as 
printed and SAVE a copy. Put a formatted disk 
with DOS files in Drive *1, then RUN the 
program. It will create a file called 
AUTORUN.SYS on the disk in Drive #1. 
Follow the directions above to use Extended 
BASIC. - ■ 




Here's a groaner for all the mathematidOTS in 
the crowd. 

Khy do programmers get Christmas and 

Halloween confused? 

—Because 25 DEC = 31 OCT 



6i<d DIM A$(10«>),HLD$(54),PT$(5l) :RESTO 
RE :N»5«» «« 
620 FDR 1=1 TO 54: READ X:HLD$(I)=CHR$( 
X):NEXT I 

62S*tOR iMlr TO 51 8 READ X : PT$ ( I ) =CHR» ( X 

) 5 NEXT I 

630 GRAPHICS ©iPOKE- 710, 0s POKE 709,14: 
LIST 640,650 

635 GOSUB 750 

640 REM . Extended Basic 

644 REM . by Jim Nangano 

650 OPEN #1,8,0, "01: AUTORUN.SYS" 

651 CD=a0 

655 POKE 82,0: POKE 83,39:? :? "Records 

left to write: "!:POKE 755,0 
660 TRAP 900:READ A$:TRAP 40000:? CD;" 
" i ? cm'* <28 ) ; CHR« (127 ) ;CHR«(12?> fCHR 

»(127);:CD=CD-1 >«*-~; 
670 Y=USR(ADR{HLD$) ) 

680 IF LEN<A$)<5<» THEN N^INT ( (LEN(A«) + 

0.5) /2) 

690 X=USR<ADR(PT*),ADR(A*) ,N> 
700 GOTO 660 

750 ADDR=ADR(A$) s HI=INT (ADDR/256) : LO=A 
DDR- (HI* 256) 

760 HLD» (7 ) -CHR» (LO) : HLO» (25) iCHR$ (LO) 
:HLD$(41)=CHR$(L0) 

770 HLD»(8)=CHRf (HI) :HLD*(26)=CHR*(HI) 
sHLD$(42)=CHR$(HI) 

780 ADDR=ADRmDf »*52 : HI«INT iMimif2S6) 
:L0=ADDR-(HI«256) 

790 HLD* (2i )t«CHR* (LO) : HLD» (38) =CHR* (LO 
) 

800 HLD$ (22) =CHR* (HI ) s HLD$ (39) =CHR$ (HI 

810 RCWRN - * 

900 CLOSE #1:? :? "Done.":? :? :? :? 

909 POKE 755,2: END 

910 DATA 104,162,0,160,0,189,2,1,201,6 
4,48,3 

920 DATA 24,105,9,10,10,10,10,141,4,3, 
232,189 

930 DATA 2,1,201,64,48,3,24,105,9,41,1 
5,24 

940 DATA 109,4,3,153,2,1,200,192,50,20 
8, 1,96 

950 DATA 232,184,80,209,0,0 

960 DATA 104,104,133,207,104,133,206,1 

04 , 1 04 , 1 33 , 204 , 1 69 , 0 , 1 33 , 205 , 1 62 , 1 6 , 1 6 

9,11,157,66,3,169,0,157 

970 ©ATfr 72 , 3 , 1 57 , 73 , 3 , 1 64 , 205 , 1 77 , 206 

,32,86,220, 132,195, 16, 1,96,230,205,165 

, 205 , I 97 , 204 , 208 , 223 , 96 

1010 DATA FFFF0FlF67lFfiS0C8D531FA^TO» 



—6>— 



r 



54 1 F A207 A97D9D 1 A03E8A9 1 F9D 1 A03A9728DE7 

02A92E8DE802A919850CA91F850DA508F0 
1020 DATA 042050 1F60206D2C20552C20E22C 
206 1 2C207D2C606C531 F0000457874656E6*A5 
64204261 73696320312E309B7DiF7820FB 
1030 DATA F333F68B1FA3F633F63CF64CE4F3 
80 Al 2B A9 1 F48 A99A48ADA 1 2B4C3EF608489848 
8A48ADFB02C99BD025 A0009 1 2420D4 1 FEA 
1040 DATA EAEA202220207320B013BDC22085 
D 1 204D2 i 90062043224eCD 1F20822268AA68A8 
682860A000B1 F3C940D02BC8C8B1 F3C99B 
1050 DATA D02388B1F3C944F00AC945F019C9 
58F022D0 1 2A94C8DAF 1 F A9CD8DB0 1 F A9 i F8DB 1 
1F20482B60A9EA8DAF1F8DB01F8DB11FD0 
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A00eA97F8D3520A9208D4a20BlF5C99BFOJI>29 
7FC922D003205220C9619008C97BF004B0 
1070 DATA 0249209 1F3C830034C2E206048AD 
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A9FF8D3520A9008D48206860A200A000BD 
1080 DATA C27920742120302FC92EF009D1F3 
D027C8E84C77 20E8B 1 F3C92EF0 1 0a8BDC2203« 
eACBD 1 F3D0 1 0C8E84C8A20BDC22008E828 
1090 DATA 10F8C81860BDC22008E82ai0F8E8 
E8E8BDC220C9iBF0034C7520386052454E2E55 
4D424552800F8A2244454C2E4554458003 
1100 DATA 222644492E524543544F52598009 
E82652454E41 2E4D458020A62745524 12E5345 
8021A6274C4F434B2E8023A627S54E4C2E 
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E3275245502E4C41 43458040 1 A2858522E4546 
80e8B22953492E5A458000B62A4D41522E 
1120 DATA 47494ES003232B444F2E53800047 
mB 1 B8 A4820022D20 1 22DA5D I F0 1F2940D&48 
A5D1 2920D0 1 5A5D1 2907D026A5D1 2908F^ - 
1130 DATA 09206D2C20552C752170224CF321 
A9 0085F 268 AAE8 1 860A900S5F2B i F309809 1 F3 
68AA38608DA«32BA90 1 8D4222A2e08E9F2B 
1140 DATA B1F3C920F023C92CF00FC99BF0BF 
C93^590D3C93A901D4C81214EA02BF0AF0£4222 
«e9F2BE8E88E9F2BB 1 F3C99BF09EC84C9C 
1150 DATA 2184F22000D8A5F24820D2D9AE9F 
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Dl%EBS2t«tt3C92CF00FC99fiFe2 1 C920F0 
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F3C950F013C945F007C953F0034C8121A9e08D 
4 1 224C782 1 A5D 1 498085D 1 204A2C20C22C 
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210000A98085CBA90585CCA98985CDA90585CE 
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1180 DATA F3S810F8206D2C20552CA200A971 
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60BDC32<»^&DC22M86eA90dWA22BI^2 
1190 DATA 2B3045AD942B3040AD962B303BA5 



D 1 290 i Fe 1 020092C A000B 1 CB8D9 1 2BC8B 1 CB8D 
922BA5D 1 2902F00CAD9 1 2E:8D932BAD922B 

A9008D962B4CDF22A91 1 4C262DAD952B0D962B 
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^ 1210 DATA 034CA22A2l£^BB2520B22B9«034C21 
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CD20AA2520A32B4CFD22A000A9FF91CDC8 
1220 DAT^ 9iCD20B825A001BlCD8Ol»32E88Bl 
CD8D022EAD922B«>»t1KWmtB8D002E2ODF2D 
90034C6E23 A000B 1 CDA0029 1 CDA001 B 1 CD 
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1410 DATA B1CB8D032E88B1CB8D022EAD942B 
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by Todd Heitzner 



In this article I MMQjms the three most 
widely used Atari assemblersi Atari's 
cartridge assembler^ OSS's macro assembler 
"MAC65" (cartridge)f and Atari's maaro 
assembler "AMAC^c 

The first and simplest is Atari's cartridge 
as5Miblir« HMle it has the lowest pricet it 
also has the fewest features* (It does 
however have a debugger^ which can help once 
you have asMmbled your program^) This 
assembler is probably a good choice for 
someone new to assemblers as it is widely 
tMd mUi known* It also has an aifi^intage in 
that the editor and assembler are together* 
Thif means that you can edit a program^ 
iMHWfibto itf and if it has «m^s you can edit 
again instantly* One of the disadvantages of 
this assembler is that the source program 
must b# Ml memory or in one file on disk or 
cassette* This limits the size of a program 
you can assemble* It also has a few minor 
bugiN T^ i» Mceptable but could be 

better* There is an addendum available for it« 

The OSS "HAC65" is also now available in 
cartridge form# It used to be available on disk 



only but was enhanced and put on a cartridge* 
It is compatible with the Atari cartridge 
assembler but has a number of additional 
capabilities^ including the ability to assemble 
a program from more than one file and to 
define macros* A macro is a user-created 
instruction in assembler which substitutes for, 
a number of instructions in the imassembled 
program* MAC65 includes the editor, 
aMamblerf^and a debugger (it differs from the 
At<»ri^^ m assembler debugger)* As Hr 

as I know no real bugs have been found in it 
yet* The manual is probably the best of the 
three as it seems to describe all the features 
in detail* including the macro fejktMrest 

The last assembler is the Atari macro 
assembler "AMAC"* The main disadvantage is 
that the editor and assembler are two 
separate programs* Each program in itself is 
very powerful but they must be used 
separately* This means you must first load 
the editor* edit the assembler program* save it 
to disk* load the assembler* assemble the 
program to disk* and if there are any errors 
stinrt all^ 0V«r* i^oth^ «ligMr tfisadvantage is 
that the program is copy-protected* this 
however can be disabled easily enough* One of 
the major faults of this assembter is that it is 
not compatible with the catridge assembler* 
but if you are willing to accept the 
incompatibility and the separation of the 
editor and assembler it is not too bad* In 
terms of raw power this assembler is probably 
the most powerful of the three* It too is a 
macro assembler but is more powerful than 
MAC65 in this respect* As to bugs in it* the 
only major one deals with its output to the 
printer* If you print out to the .printer 

mipnilly ii^m ok^ if you upi an EJECT 
oifiimand or any commiiid which does an eject it 

will eject out paper and will start the next 

page in the middle (it supposedly works fine on 
the Atai^ 8!^)* It also has a vmy liimted 

manual for the capabilities that are in it* for 
the mo^t part you will have to learn by trial 
and error* 

I hope I have helped you by describing these 
assemblers* If you inmt any help with 
assembler language* the MACE SIG-Assembler 
is still active* come to a meeting and we will 
try to help you* You don't to know 

assembler* 



9 




by Kirk Bevitzer 



It occurred to me that a lot of really new 
uwBfrm might lie wondering what a modem is and 

why they do or don't need one* So 111 start 
from scratch* 

A modern^ which is actually a 
MOdulator-DEModulatort is a device that 
connects ym^ computer to the telephone and 
allows you to 'talk' to other computers around 
the country* Here are some common 
expressiura itfNi^ ttoir meanings! 

Acoustic modem - You insert the handset of 
your i:eleph€in# :bitG cups« 

Direct Connect - The modem plugs directly into 
a iTKXtoiar telephone jadc« 

Interface - A device to connect the modem to 
the computer* 

Amodem - A terminal program for the Atari 
computer that supports ATASCII mode and 
XMODEM transfer* 

TELELINK - A relatively useless terminal 

program by Atari* It does not support file 
transfer or ATASCII* This is what is built 
into the Atari 1030 modem* 

ASCII - The standard 'character set' 
computers use to talk to each other* 

ATASCII - The Atari-ASCII character set* In 
this mode Ataris can ccMnmunicate with each 

other using inverse video and control graphics* 
On a BBS this is known as "ATARI MODE" 

XMODEM PROTOCOL - An error checking 
method of transferring files from one 
computer to another or frcm a to a 

computer terminal* XMODEM is a feature 
included in Amodem and the MPP Smart 
Terminal* 

AMIS BBS - Atari Message and Information 
System* It's the standi^d format for just 
about every Atari Bulletin Board System in the 



countiy* MACE operates the original AMIS 

SYSOP - The SYStem OPerator of a BBS* 

So there's a little description of what it all 
means* This is a bare bones beginner's 
dictionary but it shoUd help §et you started* 
For more information on various types of 
modems and interfaces see "Modems and 
Interfaces" Ml the December '84 ismm af the 
MACE Journal* 

So what's in it for you? Hell there id^ all 
kinds of things to do! First, there are the 
Atari BBSs* A BBS offers a message base 
where you can read and leave messages for 
other users around the country or within your 
own dub* There are hundreds of great public 
domato filM for the taking and the joy of 
uploading a file to the BBS* Stuck on a 
problemi need help on an adventurei just le^ye 
a messaige* 

There are also a lot of pay fiervicBS available 
such as the Source or Compt^rve iht Dow 
Jones* But the point is, if you get a modem 
the "What can I do?" question will almost 
never get answered* The possibilities are 
almost endless! 

So with that, I think I'll boot up my 
TELE-CHESS program and call a friend* See ya 

next month* 



February 19th 



Officers' reports 

Group discussion led by Kirk Revitzer 

President of MACE 

Activision's Decathlon demo, by Eric Schif f er 

Party Quiz demo, by Mike Lechkun 
Decision software demo, by Scott Garland 
Home Energy Analysis demo 



lO 



by Kirk Reyitz^r 



I hope you wanted to know how to send a file 
from one Atari to another using Amodem 
because that's what I'm going to talk about* 
Firstf the rnxkm itself should be in full 
duplex* There really isn't any need to adjust 
that at all* Half or full duplex is an option on 
the Amodem program and that's what we'll use* 



Sof novr^fitrtitial dhmdkMi^ 
1* Boot up Amodem 
2* Set the baud rate (300/1200) 
3t Sst ^ASCHmode 
4« Set half duplex 

Decide which modem will answer and which will 
originate and establish your connection* At 
this point you should be able to type to each 
other* To send or receive* use the S or R 
option of Amodem just as you would with a 
BBS* When the receiving end says he's ready 
watch for him to push his START key* ^Ftm 



reaiving end MUST push START first* Hhen 

he does you will see a small white line on your 
screen* Then# you push START* If you have 
done all this as you read this article you'll 
notice your file is now being sent* Gee» that 

was easy! r 

Now for some other stuff* 
Do you have a 1030 modem and wonder why you 
have problems with an MPP BBS? Well, it's 
not your fault* The MPP set for 300 baud is 
actually running about 305 baud* 
Unfortunately* this is not within the tolerance 
of a 1030 modem* If an MFP sets its baud rate 
to 297 or 298 the connection will work okay* 

Here's a Uttle tid-bit hot off the BBS* It 
seems our Commodore friends have developed 

a terminal program that will emulate an Atari! 
So if you Sysops see someone in ATASCII mode 
you'll just have to wonder who it really is! It 
seems they can send the ATASCII <RETURN> 
and read the control & inverse video but I 
don't think they can send it* Oh well» back to 
the drawing board! 
Til next month*** 



Visions 



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PAPER 

for a Good Look 



CASSETTE CORlMEIi 

by Mike Landis 

It's the beginning of the year and time for a 
refresher course in the 410 & 1010 program 
recorders* 

HANDLING CASSETTES: 
Be careful with cassettes; they can be easily 
damaged ♦ Avoid touching the surface of the 
tape itself* No matter how clean your skin is# 
natural oils will cxintaifimate ths ta|ie# Make 
sure you put tapes back in their cases when 
they are not being used* Never store them in 
hot mrmasf direct sunlight* or near magnetic 
fields* 

^MTTING BLANK CASSETTES: 
The Atari recorder uses only audio cassettes - 
never digital cassettes* You can't go wrong 
with the best quality normal-bias tape* Good 
quality tapes will work too^ but avoid cheap 
barf ail) cassettes* They tend to jam up after a 
whilet rendering your valuable programs 
inaccessible* 

LABELING CASSETTES: 

You should label every cassette with 
information about the programs it contains* 
TMs prevents ths lie^ache of seard^g 
through cassette after cassette for the 
prqgram you need* 

WRITE-PROTECTING CASSETTES} 
Each cassette has two notches in the rear 
edge* Hhen the notches are uncovered » the 
recorder can sense the holes and will not 
record on the cassette* New blank cassettes 
have tato covering the holes so the tape can 
be recorded on* You can protect important 
programs by knocking out the correct tab and 
exposing the hole* Later^ if you want to 
record over a protected tape^ simply cover the 
hole with tape* 

Each cassette has two sides to it* One notch 
protects one side» while the other notch 
protects the other side* To determine which 
notch is correct, hold the cassette so the 
exposed tape is toward you and the side you 
wish to^rotect is facing up* Remove the tab 
on the left side to prevent recording over the 



side facii^ yp« 

THE TAPE COUNTER? 

The MACE cassette library tapes always start 
with the iiMNHif Make mmt the cassette is 
rewound, then set the counter to zero (000)* If 
you want to bypass the menu and go right to 
the first pragframf start f rofii zero (000) and 
advance the tape to 30 and then CLOAD* 

If you put a new tape into the recorder^ don't 
assume it is rewound* Depress the REWIND 
lever just to be surei then reset the counter* 

NOTE* Tape counter speed varies from one 
recorder to the next* Thus^ tape counter 
readings noted on one recorder maynot match 
those of another* It is always recommencted 
that you change the numbers on the menu or 
tape listings to match your recorder* 

I hope I have given you some insight into your 
wonderful animal* Next month# we get 
technical! We will talk about LOADing a 
program, SAVEing a programii One-Step LOAD 
RUNr chaining programs and» yest sven 
program recording formats* Wow! I can't 
wait!!! 



by Scott Garland 
MACE Program Coordinator 

My job as Program Coordinator of MACE is to 
arrange a meeting for each month* As such» I 
demo some software* arrange for demos by 
other people* and have talks on topics of 
general interest* MACE is a user group * and 
therefore all of us* as members* must do our 
part* I do my part by arranging and running 
these meetings* it is up to you to do your part 
by coming early and setting up chairs* staying 
late and putting away chairs, or volunteering 
to do demos* (By the wayt if anybody mit there 
could do a demo of ti'^ new SynTrend* 
SynGraph* SynFile* or SynCalc* please offer 
y^im services*) My phone number is 851-9453* 
Feel free to call me any tifw iM^wetm 2J30 pm 
and 9J00 pm with suggestions* offerings of 
help* or my questions* I can't do it alone* I 
need yoir help* as members of HA£B» 



12 



liAP9(ZrANrr MOST,., c<?/^^ArASii'*r^ tAiiry rHw 

INPOSriZyf STAN 0 Af^o! 

^ANVO €SO Se-f^iBS COM 







ojifH ATA At: iM^'cc SH^uj 



^S^S' VU. 12. mice /Z^ • 86^(2l^t^ • S<^S-PSZ0 



by Acti vision 

Reviewed by Scott Garland and Michael 

SchiffeF 



Beamrider by Activision is a Tempest-type 
shoot-em-up game in which you protect the 
"Earth-Space" by blasting aliens descending 
five vertical beams« You are equipped with 
unlimited "laser-lariats" which destroy only 
certain enemies} the others may ^ eliffiinate^ 
by your torpedos» of which you possess three 
per sector* "Yellow rejuvenators"* when 
caL^ht# will add a ship# but can kill you after 
being shot« A sector is deared after killing 
fifteen "enemy saucers"^ although countless 
obstacles* such as "space debris" and 
"bounrars* will hinder you* At the end of each 
sector* the mother ship appears, giving you a 
chance to destroy it for a bonus* which is by no 
means easy* Each successive sector brings 
faster action and new (and improved!) enemies* 



Mthough slow at first* the game is devilishly 
fast-paced and challenging in later sectors* 
After playing it ^4 number of times with 
friends* our opinion is thisJ BEAMRIDER is 
addictive and exciting* Although not a complex 
gaiDe* B£AMRp}£R is worth purchasing* 



by Lord British 



Origin Systems* Inc* 



Reviewed by Michael Schiffer 

EXODUS is third in a series of critically 

acclaimed graphic role-playing games by Lord 
British* It allows up to four characters of 
varying mass (such as elves* dwarveSf^^d 
bobbits (sic))* and classes (such as clerics* 
wizards* and thieves)* Your quest is not 
known to you at first* save ^©p the nebulous 
indication that evil has returned to the world 
of Sosaria and that your party has been 
commissioned to find out how to stop it* You 
must travel about the countryside* fighting 
monsters with sword and spell* asking 
questions in towns* and exploring dark 



dungeons* Each character class is given 
different powers* and supplied with minimal 
armor* weapons* gold* and provisions* As eadi 
character gains experience* he* she* or it also 
gains power* but the monsters and puzzles 
grow more difficult to overcome* :^ 

EXODUS includes a player reference card* an 
instr^€!ttcm book (which still requires you to 
figure some things out)* a book of clerical 
spells* a book of wizard spells* and a beautiful 
doth map of Sosariat The graphics are rather 
spartan* but give a good idea of what is going 
on* It approxiirotes all of the standard 
features of a game such as Dungeons and 
Dragons(tm)* and you don't need to get a grdi^ 
of people together in order to play* I heartily 
recommend this for anyone who enjoys 
role-playing games (and who doesn't?) and tiis 
both dedication and stamina* 



by David Crane 

Activision 

t^umedi by Eric Si^f^r 



Activision 's Decathlon involves all the events 

from the 100 meter dash to the pole vault to 
the grueliqjBi 1500 metpf raceiL It |s hard on 
joysticks* because while * ' ruining or 
approaching you have to move the stick back 
§nd forth quickly* This cartridge can be used 
with any Atari home computer* 

The game itself is tiring* It begins with the 
100 meter dash which is rather easy* Next is 
the long jump* then the shotput* The high jump 
is one of the best* in this event it shows the 
approach including the angle you need to make 
the jump* After the high jump is the 400 meter 
race* Next is another race* 110 meter hurdles* 
which shows very good graphics* Then comes 
the discus* the pole vault* and the javelin* 
Last is the difficult 1500 meter race which 
seems endless* Many of the events are 
basically the same* but Activision uses fine 
graphics and some special highlights including 
a real-time clock for races and a "strength 
bar" to tell your relative iwining or af^roach 
time during events* Activision 's Decathlon is 
one of the better sports games on the market* 



ANTIC SPECIAL BULLETIN, REPRINTED BY 
PERMISSION OF ANTIC PUBLISHING INC» 

1/2/85 
by^JHAT FRIEDLAND 
ANTIC aHfOR 



Antic Hagaxme got 4^^^ look at tNi 198& Aturi 

Computer Line-Up three days before it was 
due Cor unveiling at the Consumer Electronics 
SN^ Las Veg ast - - ^ 

This Antic JPreview was hosted at the Atari 
Engineerings Center in ajnnyvale by Sig 

Hartmann, President of Atari's Software 
Division^. awJ^J^ Tramiel# President of the 
Atari Corp f ' -^^^j^^^^^t^^- . .^.^ - 4^ -^^i.-;. ■ 

Prices Jor many of the new productai vi^re not 
going to lie ^nali2«d tm^ 24 hot^ tK^^ont 
opens* Manufacturing of the new computers 
wofi't. be{^ MTiier ti^ March» wluch means 
they ¥mn^ appe^M^inf in the at 
least May or June* 

Atari will bm stoii#faig ttmm mm 8-bit 

XL-compatible computers at CES» A 128K 
version > the 130XEf will be priced around $200* 
^e^ 45X£|c tli»^ Ma^iieiierirti^ wiU 
cost around *100» 

km^^omlm and cases of these machines 
will be dramatically changed ♦ They will be 
smaller versions (no 10-key pad) of the 
•specbaiaiUur 16-bit computer hoiis»^« Inside 
the XE computers^ the circuitry Iwmi twrtm 
simplified and chip functions have been 
combined* &tffi Tramiel said that this will 
make the XE a more reliable machine than the 
XL while maintaining 100% compatibility* 

There will also be a luggable 8-bit XE that 
comes with 128K# a small video screen and a 
disk dfivet ^^^^i^i#e 91^ for around 
$400* 

.Xbe XE comp4»i^s will use a new DOS 2t5f 
which Sam Tramiel said is very similar to the 

classic DOS 2*0S* The new DOS is necessary 
so that the X£s can accept the new 5001C 3 



1/2" disk drives as well as the current 1050 
drive* Tfy^ ^jMi^ has not been 

changed* 

fiartmann & Tramiel brought ^p and agreed 
upon the necessity of exdl^^g DOS 2*5 for 

the DOS 3 packaged in hundreds of thousands 
of new SOOXLs sold at Xmas* They were very 
opi^ to Antic's suggestion that DC^ 2*5 be 
uploaded onto the CompuServe Atari SIG and 
distributed^ta usfJ'S'-. groups, as soon as it's 
finalized* 

Hartmann also proposed that Antic assemble 
users' qiMTstions via CompuServe e^di^^iORth 
and turn them in to him* He promised prompt 
answers from Atari's top management through 
Antic* Sam Tramiel w« entftusiastie^^iboiit tta 
arrangement and Antic is starting it right now! 
Upload your questions for Atari on the Antic 
Electronic I/O Board and we'll be online wiib 
the first round of answers before the end of 
January* r^ry.-.-^::^^:-^---^^ 

ANTIC WRITE-INS SAVE PARALLEL BUS!! 

Good news that many of us have been waiting 

for! The XE 128K computer will maintain an 
open parallel bus for plug-in peripherals* The 
PBI will wnm be improvMl over tbe onrrent XL 
format — with improved timing and a biriilt^in 
+- 5 volt power amplification* 

The last-minute decision to continue the PBI 
came at an engineering meeting called by Sam 
Tramiel in response to Antic's v^rite-in 
campaign on CompuServe's SIG^ATAHX»^^ 

As^^pr, tbi t4«o new 16-bit machines> they can 
be described m one wcnrd — phenommalr 

The 130ST is a nan-iexfmMi^blm 128K computer 
and the 520ST carries 512K| that's the only 
difference between them* They both use the 
MotoroliL^ffiKX) chip wbi£b is also in the Apple 
M^ntosh* They both use Digital Research's 
super-fast Macintosh-like GEM user 
interface^ which sits on top 4tf XNR^s £P/M 68K 
operating system* 

Each model also has 196K built-in ROM 
containing GEM and CP/M 68K* An Atari 

mouse will be available to run OEM's icon 
menus* Both computers will be capable of 



running the highly-rated DR version of Logo* 
C €^ I^TCal will be the development ^guages 
of choice* 

The state-of-the-art keyboard for the 14*Wt 
machines includes{ full Selectric-style key 
layout » 10-key number pad» cursor pad with 
Help and Undo keys^ and 10 funttiai? keys* life 
entire back of the casing is honeycombed with 
ports^ including! parallel and serial 
interfacesf MIDI musical interf FBh etc« 

The one sad note at Antic's preview was that 
the long-rumored AMIE 16- voice sound chip 
was not totally ready for production yet* The 
AHlEf which is said to emulate human speech 
and singing with unprecedented accuracy » will 
be incorporated into the '85 Atari line later in 
the spring and will be identified by adding the 
letter M to 8-bit and 16-bit models that 
include it* 

Another '85 breakthrough is Atari's sleek» 
compact 3 1/2" disk drive with 500K storage 
capacity* Sam Tramiel said this drive will be 
in the increditily low price range of $100* 
Tramiel told Antic that the 500K drive^ which 
uses the same sturdy 3 1/2" disks as the 
Madntoshf will be oofupatible with both the 
16--fait and 8-bit computers* 

"Ne've had long discissions about the issue of 

disk compatibility/' said Tramiel* "But our 
conclusion is that we're going to strongly 
erMSoyra^ software ik^elopers to bring out 
their new programs primarily on 3 1/2" format* 
At the low price we'll be selling the new drive 
for — frmkly &Hbit users would be foolish not 
to eventually upgrade to a far superior product 
and format*" 

However^ the current floppy-5 1/4" 1050 disk 
drive will continue to be manufactured as long 
as there is a mtEu^ket for it* 

In yet another new move* Atari will be showing 
a wide line of printers and monitorst wMdi 
will be aggressively marketed for use with 
IBM and Apple computers as well as Ataris* 
Hhen asked who was actually fpanufacturing 
these new peHpheralsi lam^ W laughed 
and saidt "Japan Inc*" 

The Atari printers aU aggressively 



low-priced — will include a 12-cps 
daisywheelf an 80-cps dot-matrix* and three 
$50-100 thermal transfer models* including 
one that prints in color* 

The monitors include a 12" monochrome for 
iriKiut *100 — with a built-in 80-colufm card 
for the XE and XL 8-bit series — and a 14" 
color monitor for about $200 which will 
compete with the popular Commodore color 
unit* A 640x200 resolution RGB Analog model 
capable of displaying 512 colors will sell for 
around $300* There will also be a $150 
high-resolution 640x400 monochrome model for 
the ST series* 

Atari also plans to show a monitor with a 

built-in floppy disk drive* plus a low-cost 
(around $50) 300-baud modem bundled with 
software for uploading and doMfdeadif^f 

Software president Hartmann described 
Mmn^^Md as '^switching from a uompu^ 
game company to a microcomputer company*"* 
He said that Atari Software will primarily 
publish entertaining and easy-to*^e 
productivity programs* "We'll be very 
selective about games* only publishing games 
that we believe have a real chance to become 
major hits*" 

By the day tmf&^ CES* Hartmann #xp«eted to 

sign the contract for Atari to bring out an 
integrated program comparable to Lotus 1-2-3 
— but with code so compacted that it will run 
on 64K* If this deal is finalized in time* Antic 
Online will upload a description of the product 
from CES* 

Also under development is AtariWriter Plus* 
which will include integrated mailmerge and 
spelling checker* It is to all run on one disk 
at 128K* Hartmann said he is determined to 
reach out for user group feedback in the 
fast-moving software market* He specifically 
wants major users' groups to act as beta 
testers fe»^ new Atari softwanN 

As a first step towards this* Hartmann said he 
will bring top Atari executives to meet with 
users' group officers at the special 
invitational Worldwide Users Network meeting 
which Antic will hast at our offices during the 
West Coast Computer Fair in March* 



XHE 3HELL GAME 
CRACKING ATARI LOGO 

by Ann McBain Ezzell 



Last time we discussed some safe locations 
for storing maichine language routinest and a 
couple of methods to use to put such routines 
into those locations* Now we can go on to 
create and store a display list interrupt (OLD 
routine tliat you can use to add ^t^PiNit to 
your Logo screens* 

The procedures which follow are written so 
that they can be used whether or not you know 
anything about DLIs* I am planning an article 
specifically about DLIs for a future Journal^ 
but there isn't enough room for a complete 
explanation here* Let me just say that a DLI 
is a way to change certain aspects of the 
display screen to enable you to (for example) 
have mcMre colors or different character sets 
on the scrMn at the same timet 

The particular routine which I have written for 
this article Vstm )^ change the background 
color part of the way down the screen* You 
can set the background with the primitive 
SETBG aaiGmuml^f ^wm^jsm these procedures 
to change some lower part of the screen to a 
different color* Here is the source ccMle for 
the m9£him lafMpM^ mitine which does the 
work* 

PHA 

LDA #198 ;i98 = GREEN 
ST A $D40A JWSYNC 
STA«D01A jCOLBK 
STA$D01d JC0LPF2 
PLA 
RTI 

After saving the value in the accumulator (by 
pushing it on the stack}f it IsMki the 
accumulator with the desired color value* It 
addresses WSYNC to synchronize the color 
change with the hc^ontal sweep of the TV 
electron beam* then puts the new color into 
COLBK, the background color^ and C0LPF2# the 
colm of pli^field 2 which is also the 
background color for the Logo text window* (If 
you leave out this statement^ the text window 
will be a different coli»r« but you wilLbei^te 



to see lines drawn with pen 2 on the bottom 
part of ttm mcmm* Other wiset they will iie 

the same color as the new background and will 
only be visible on the top part of the screen*) 
V^tf the accumulatcn" value is restored and 
the routine returns from the interrupt* 

TO DLI :linenum **C0LR 

CHECK :linenum 

WRITE.DLI {COLR * 2 

PUTROUTINE 13284 JDLI 

DISABLE*NMIEN 

CHANGE*DLIST 141 JLINENUM 

SET*VECTOR 

ENABLE*NMI£N 

END 

The two inputs to the procedure DLI let you 
specify where on the screen the change is to 
take place and what the new color is to be* 
The value for !LINENUM must be from 1 to 75 
to avoid messing up the display* Values for 
«COLR are those given on page 26 of the Atari 
Logo ReferencB Manualt Th^ can range from 0 
to 127» 

'The first subprocedure checks the value of 
thinmmt lialts if yon have entered an 

invalid number* 

TO CHECK JLINENUM 

IF OR JLINENUM < 1 JLINENUM > 75 CPR 
[USE VALUES FROM 1 - 75 ONLY] PR CFOR 
FIRST INPUT] ♦CALL^2?3 

END 

(♦CALL 39929 retwfti ^ to TOPLEVEL.) 

The next subprocedure writes the DLI routine^ 
inserting the color value wMdh you have 
provided as an input to the main procedure^ 
DLI* The input value must be HMjltiplied by 
tiNKi hmcMmm the Atari uses even numbers from 
0 to 254 for its colorst while Logo uses all 
numbers from 0 to 127# 

TO WRITE*DLI JCOLR 

MAKE "DLI (SE 172 1693 JCOLR C141 10 212 
141 26 208 141 24 208 104 643) 
END 



17 



The numbers which make up the list *DLI #r# 
simply the decimal equivalents of the 
assembled version of the Sdurcet coite Ust«J 
above* A value of 72 is interpreted by the 
AtBjri as Push the Accumulator pnto the stack, 
and w cuif 

The priimtive SE (for SEntence) outputs a list 
consisting of the ri«ments in its inputs* When 
there are more than two inputs, you must 
enclose SE and its inputs in parentheses* 
Remove the three numbers "141 24 Z08" if you 
do not want the text window the same color as 
the new background* You will then be able to 
see things drtt%im wth pen 2 on the changed 
part of the screen* 

Itext, PUTROUTINE as defined last month is 
used to store the DLI routine at the beginning 
qf the shape table (location 13284)* It will 
only overwrite shape 0, so you are fref JtiRM^e 
any of the other shapes* 

TO PUTROUTINE ILOC {ROUTINE 
IF JROUTINE = C ] [STOP] 
•DEPOSIT JLOC FIRST {ROUTINE 
PUTROUTINE JLOC + 1 BUTFIRST {ROUTINE 
END 

Location 54286 is the non-mfiskabte interrupt 
enable (NMIEN)* Bit seven of tWs lliattoii 
determines whether or not display list 
intwnrupts will be acted upon* Atari Logo has 
its own "Display List Maker" 
automatically sets up the proper interrupts 
when you switch between Full Screen (FS) and 
Split Screen (SS>* Before you go about setting 
up your own interrupt^ you must turn off 
KMim m hanging up the system* This 
next procedure envee the value in NMIENf then 
puts in 0 to disable the interrupts? 

TO DISABLE*NMIEN 

MAKE "NMIEN ^EXAMINE 54286 
♦DEPOSIT 54286 0 

END ' - - - 

Now you are free to tinker with the display 
list and reset the wctiars wWdi^ wntrol the 
interrupt processing* 

TO CHAKGE.DLIST JNUM {UNENUM 
♦DEPOSIT (14080 + 5LINENUM ♦ 5>HIUM 

END 



TO SET*VECTOR 
♦DEPOSIT 512 0 
>MPOSIT513 54 

END 

The offset of 5 4ft JSHANGE*DLISX is there 
because of the structure of^e display Ust* 
When this procedure is called in DLI, tNUM is 
given the value of 141* which is 128 (bit seven 
set) plus 13 (normal value f&r grafAmm 7 
display line)* This indicates that a DLI should 
be executed at the chosen screen location* 
Locations 512 and 513 hold the addiress Oow 
byte, high byte) of the DLI routine to be 
executed, which is 13824 (54*256 + 0) in our 
case* . 

Once the display list and vector have been 
changed f you must reset vi4*pj9f J6^^ 

TO ENABLE*NMIEN 
♦DEPORT 54286 128 + JNMIEN 
END 

Adding 12B to the firevi^^^al^ that 
bit 7f which controls DLIt» will beset* Once 
this procedure is run, your new DLI will take 
over and yai^ witt be aWetAo use )WHr 
screen however you want* 

When you iig# tNsse f»W3Ktoe»f^ 3^ 

SS or FS first* If you issue either of theM 
GO0imands After running DLI, the Logo Diplay 
List Maker will take over and the display will 
change back to its normal state* If you are 
going to use the DLI routine more than once in 
your procedures, call SS or M3 *° 
clear out the old display list* 

Remen*er that Unes^ drawn with pen 2 will not 
be visible on the bottom part of «ie «3reen if 
you change the text screen background to 
match the new background* If you need to use 
pen 2, remove the numbers "141 24 208" from 
the list in WRITE*DLI* 

A DLI could also be used to change c»ieor 
more of the pen colors at some point on the 
screen* or even change the turtle color, so that 
a turtle would change color as it moved up and 
down the screen* The addresses to use for the 
i^ious pen and ti.tt#e cpiprs are! 



IS 



$0044 i2Z 2mi COU>F0 Pen 0 
%m\7 COUm Pen l 

*D018 (24 208) COLPF2 Pen 2 
$0012 (18 208) COLPMO Turtle 0 

$001^ ^{19 208) coLmv iMmm^ - 

$D014 (20 208) C0LPM2 Turtle 2 . 
$0015 (21 208) C0LPM3 Turtle 3 

The numbers in parentheses are the low and 
high byte equivalents of the hex addresses* 
Use these in place 0f the 26 and TXlB^'^wSmmin 
the KRIT£«OLI procedure above* 

In this case^ you ulso need tt^^tto 
something about the color of the text window* 
T^ procedure-aft, written will make the text 
winifcH# t)MI #ame as whatever color you put 
into the altered register* If this is okay^ or if 
you plan only to Pull Sc^n mode» you can 
leave KRITE*DLI as it is* The other easy 
option is to remove the "141 24 208" from 
WRIT£*OLIt which will give yw a text wijidow 
the same color as pen 2r H ymj dc^ to 
draw with pen 2* you can use the SETPC 
command to set its color to the background 
orter or n^hatever color you want to use for the 
text window* 

One #th«r thing to watch ^«#hen you start 

changing the color registers and bypassing the 
Logo Oisplay List Maker is the luminance of 
the text in the text^%#mdm#f' This is controlled 
by the luminance of pen 1* If you change the 
color of pen 1 or pen 2 with your DLI and the 
lum^iancs^NB^ pe^ -j^^iiM^ to be tto same as 
or close to that of the luminance of pen 2f you 
wiU not be able to see the characters in the 
text window* Yob may'Mve to experiment with 
different color values to get a legible result* 

If you already know how to write DU routines^ 

you could of course set up multiple DLIs on 
the screen and format the text window with 
none of these restrictions* I think that the 
routines given here will be adequate for most 
purposes^ but if you come up with a fancy 
display! fend it in and we'll publish it* 

I hope that you will find these procedures 
useful in your Logo applications* You should 
be able to €fl»ate some interesting effects 
with the added color capabilities* Next time I 
will show you some procedures that will let 
you add text to your Logo graphics screens* 



Anyone knowledgalile in R*T*T«Y* for the Atari 
800 please call Barb at (313) 23t-^l* CThere 

was an article aibout this in the July '84 Antic 
' magazine* -Ed*3 

Last month there was a request for a non-disk 
translator program for XL computers* 
Computer Software Services offers XL 
"FIX"! which they claim fixes 30% more 
software than other translators and works 
with diskf cassette and cartridge software* 
The price is $49*95 for disk or cassette ROM 
cartridge is $69*95*^^ Check out their ads in 
Antic and Analog* 

IT'S OFFICIAL! The first winner of the MACE 
Journal Best Entry Contest is Jim Wilson for 
his program Hangman* which appeared in the 
.November 1984 issue* The next contest will 
cover the February » March and April issues> so 
get those programs and articles in RIGHT 
HERE AND NOW* 



SIC3 XJi=>II)AXE 

Here is the current information on active 
Special Interest^ ^SrmjpSf Call the person 

whose name is listed for more details* 

Mmnmmic SIGi ifite€atKMiyf^9^8432 

Assembler SIGi Todd Meitzner 542-1752 
Meetings are the 1st Thursday of ea^ month* 

Next meeting* February 7th* 

East Side SlGl Mike Simpson 751-7290 
Meetings are the Ist Tuesday of each month* 
Next meeting? February 5th* The meeting will 
tw at 7i00 pm at the^iiallan Cultural 
Community Center^ 28111 Imperial in Warren 
(between Hoover and Schoenherr)* 

' FORTH SIG: Tom Chrapkiewicz 562-8506 
This group is not just for Atari owners} any 
FORTH user is welcome* 

Graphics SIG: Dan Rubyan 838-5679 

Call Dan if you are interested in joining this 

new SIG* 



BIG BIIRD'S 

A Review 
by Ami Md^an 



Hith so much "swillware'' passing itself off as 

educational and entertaining t it is refreshing 
to find some pres^Jbool software which actually 
iSf CBS Software and the Children's Computer 
Workshop have produced a program which will 
not only keep your child at the keyboard^ but 
also let her practice memory and sequencing 
skills* Big Bird's Funhouse is one of several 
Sesame Street programs aimed at the 3 to 6 
orowdt amt is %#eli iMfth the investment # 

Big Bird's Funhouse is available in cartridge^ 
disk sff)d cassette to run im^ all Atari 
computers, although the membrane keyboard on 
a 400 might be awkward to use with the 
EasyiCey overlay* I tested the cartridge 
version t and was pleased that it slipped easily 
into both my 800 and 800XL, unlike some other 
third party ourtridges which tend to sticks The 
EasyKey overlay is a piece of flexible molded 
vinyl which fits over the keyboard and is 
essential to the play of the games; it shows 
you where to press* It has pictures of eight 
Muppet friends plus areas for different 
commands such as "HIDE"t "#LAY'' and 
"LEVEL"* The molding and printing were not 
exactly aligned on the that I testedt but 
that didn't affect its use* The molding is made 
to fit the XL style keyboard, but fit 
adequately on my 800, although I found on both 
machines ttet I needed a couple pieces of 
masking tape to keep it in place* 

Documentation fw this program consists of a 

colorful, 24-page Game Play and Activity 
Manual and a quick reference How To Flay 
CM^^ About half of the manual is directions 
for the various levels? the rest is a story 
about the characters in the game plus 
suggested activities to reinforce the skills 
taught by the program* The manual is designed 
to encourage active participation of the adult 
with the childt Too often^ preschool programs 
are chosen for their "baby-sitting" 
capabilities? it's nice to see one which 
emphasizes interaction* 



The graphics aiMl sound in Big Bird's Funhouse 
are excellent* Each Mi^pet character is easily 

recognizable and nicely animated* A tune 
accompanies each character and helps you to 
remember r Meffi^' ^le^ levels of play all 
involve remembering which Muppet friends are 
playing Hide and Seek in the fynhpyse* ^ 

In Level 1, Who's Hiding?^ you invite three 
characters who then pop up in the windows* 
When you press the HIDE keyf you see tbem 
scampering around the funhouse^ blowing 
trumpetst sliding into a tub of water» and 
generally having a good time* Then they 
disappear and shutters on all but three of the 
^iAdov^s -slam shutt Two of the friends 
appeaff you must remember who is still tnding 
and press the appropriate key* If you make a 
mistake! Big Bird comes out and shakes his 
head "No"* After a second wrong guesSf the 
tune for the missing character plays as a hint* 
With a third incorrect answert the character 
pops up briefly in his window* Aftm' fmiimvm 
found the missing Muppet^ you press the HIDE 
key for the second round* This time two of the 
characters are missing* the third round» all 
three are hiding* Once you have successfully 
completed three rounds* Big Bird rewards you 
with a roUerskating demonstration* 

' ' . - _- w - ' " t 

The other levels are variations of Level 1* 
Yoi#c^i^ iimte more characters to f^ay in 
Levels 2 and 3^ in Level 3 all the windows 
remain open* so you can't count the remaining 
iii»itows to help you* In Levels 4 mA %Si% 
Bird does the inviting when you press the 
POP-UP key* Both of these levels require 
that you remember the order in which the 
friends appear* Level 5 continues adding a 
friend each ticp^ .yntil you fail to match the 
sequence* 

The games progress at a reasonable speed* 
fast enough to be interesting^ but not frantic* 
Wrong answers are corrected gently and right 
answers are rewarded with music and 
,^imation* > Gi»ti^ of the program ijir simple* 
You can press the LEVEL key to return to the 
menu screen^ or use the PAUSE key to stop and 
restart a game in progress* Once a child is 
familiar with the games» she can (and probably 
will) continue to play by herself for quite a 
while* If you have a young child^^Ci an Atari^ 
you shduM ha^e Big Bird's Funhouse* - ^ 




SECTOR 



FREE CATALOG 



ATARI 



IN TERNA TIONOL 



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378-2208 



with the Atari Computer _ 

by Kumar ^latia^ 

Essex Regional Atari Computer Enthusiasts 



Let's say you are a softwiur*. author and hav% 
just finished the next blockbuster game of the 
century! You intend to sell it in cartridge 
form but are afraid that someone will be able 
to copy your masterpiece* You have two 
options* One is never to release the program 
(don't pick this onelUf the ather is to plant one 
heck of a prote^on scheme tfmmd your 
software* There are basically two ways to 
protect cartridfle software: SOFTWARE and 
HARDWARE* If you choose just the software 
route^ like the majority of software houses do* 
the» you should write and encrypt a subroutine 
which constantly writes to the cartridge 
locations* If someone were to transfer the 
l^rt to a file and upload it into RAM^ the 
program would literally self-destruct when 
executed* The drawback is that this ROM 
process can be emulated ^ so software alone is 
a poor c^ma protec^km* W4tti^ liardware it 
is possible to devise schemes which would 
baffle #yio a top notch bandit* A well known 
company has done «cactly this} they call their 
products "SUPERCARTRIDGES"* With special 
>wrdware# these cartridge^ can "b^R-switch" 
i6K of memory in m QKmpim* 

These can be considered to be the "second 
generation" of cartridges, and although the 
principle is new to Atari computers, it has 
been used for a while in the Atari VCS game 
machine* "Bank-switching" is nothing more 
than the concept of overlaying a region of 
memory with more memory by toggling between 
different b«nks« The rest of this article 
describes in detail how you can transfer your 
own piece of softw^e into a bank-switching 
cartridge* It is MMMmed that the 4fiBMihed 
program is 16K in length and is to be 
converted into an 8K memory efficient 
cartridge* 

The first step is to organize your software 
into specific banks* A proposed layout is 
given in the theory section* Tlie-^tire^^^l^ 
program is to be broken up into four banks, of 



which Bank *1 is constant and is caUed the 

CONTROL bank* The other three banks, each 
4K in size, are to share the memory space 
*AOOO~>*AFFF (ofHT at ^ time* of «urseiV 
The control bank should be responsible for 
placing the bank needed into memory region 
*AOOO-*AFFF for operation at power-^ The 
program will be stored in two 2764 EF^IS 

BASIC objective: In essence, you want to 
ham 16K of data sitting in an 8K region* The 
prqpiosed itesign's memory map is as follows* 

*BOOO">$BFFF Bank #1 (Constant) 
«AOOO-->«AFFF Bank *2 i»D500) 
$AOOO~>*AFFF Bank #3 (♦D503> 
$A000— •>*AFFF Sank #4 (*D504) 

As you can see from the memory map, there is 
a constant 4K bank sitting at $BOOO"—>$BFFF, 
while three more banks of 4K each share the 
area *AOOO~>$AFFF* When you power-up 
with the cicuit shown in Figure 1, the cart 
defaults by putting Bank #2 at 
*AOOO~>$AFFF and Bank #1 at 
*B000 — >*BFFF* For those with wild and 
lareative mindst the supports the 

ability to bank away Bank #1* Beside each 
bank number you will find the appropriate 
ai^ress with which it is possible to toggle 
that piece of EPROM in or out* The circuit is 
wired , with the R/W (READ/WRITE) line of the 
mmmf that when you perform a WRITE 
command to location *D500, Bank #2 wiU 
immediately occupy the 4K region starting at 
$A000* Similarly, if you were to do the same 
with locations *D503 and *D504, then Bank #3 
and Bank #4 respectively would toggle in that 
memory space* (NoteJ For practical purposes, 
I chose to get the R/W lifMS-firour the OS toMrd. 
However, this signal is available from the 
cartridge slots if you wish to construct a 
PC-board for such a dra^ Consult ttm Abam 
Technical Manual for further details*) 

Now, let's translate the above into hardware* 

First of all, you'll have to burn your own set 
of EPROMS with the sofwtare* Yoyll need to 
burn two 2764 8K EPRQMs* You can 
accomplish this with an average quality eprom 
burner without great difficulty* A theoretical 
circuit is shcMi^^ii^ Fi^#-4 an4 built 
wire-wire or on a PC-board* To tiwi* the 



circuit, plug in the cartridge mtf poller up* If ^ 
you have written the driving software 
correctly^ tiie banks should switch smoothly! 

BANK-SWITCHING CARTRIDGE 

PART list: 

2 X 2764 EPROMS (450 ns or faster) 

1 X CD4514 Multiplexer/Latch IC 
1 X 74LS02 NOR Q«t» IC 
1 X 74LS08 AND Gate IC 
1 X lOK 1/4 watt resistor 
1 X PC BOARD for housing EPROMS# 
1 X Small piece of perforated board UOl inch 
spading) 

* NoteJ The PC BOARD for holding the two 
2764 Eproms is available for $7»50 plus 
postage from} 

CONVOLOGIC Inc» 
421 Bay Tree Lane 

Long wood, PL 32779 
(305) 869-6630 

With a sharp X-ACTO knife, cut the trace 
going to pin 2 on each EPROM socket as shown* 
Cut the traces goif^ to pin 20 of> both sockets 
and solder to these connections as shown in 
Figure 2# Finally, cut the trace going to "A" 
(on the solder sicfai of the board-labelled) on 
the F*C board connector* This will allow you to 
disable only the top 8K of RAM when this 
cartridge is inserted » The actual circuit can be 
built on perforated board due to its simplicity* 
One last connection must be made to access 
the $D5xx select line* Although this line is 
available through the cartridge slot, the above 
PC board does not provide a trace for a 
connection* Therefore# the signal must be 
"stolen" from the 74LS138 IC on the Atari OS 
board (first slot in Atari 800)* This select 
line is available on pin #10 on IC Z401> If you 
have an Atari 400 you will have to open the 
computer case to gain access to solder to pin 
#10 on IC Z105 (74LS138)* To run the cart, 
insert the finished product into the left slot 
with the chips facing AWAY from the computer 
and power up* 

THEORY OF OPERATION? The theory of 
optCAtion for the schematic in Figure 1 is 
quite straightforward* The circuit consists of 
two 8K EPROMS (Electrically Programmable 



Read Only Memory devices), thereby providing 
the necessary 16K data storage for the object 
code* With the aid of two more integrated 
circuits (IC) we can perform bank^ witching* 
IC #1 is a CD4514, 4-BIT LATCHED/4-to-16 
Line Decoder and its job is to act as an 
address decoder for the unique ^Midresses 
$D500, *D503 and *D504* When any address in 
the *D500 page ($D500~>*D5FF) is selected 
the strobe on the latch (pin 1) goes LOW 
thereby latching the data (actually address 
lines) fed into that memory page* For example^ 
if you access *D500» either with a READ or 
WRITE command^ IC #1 will force pin 11 to go 
HIGH* This activates IC #4 to select Bank #1* 
If you access *D503f then IC #4 will come baick 
into use again BUT address line A 12 on IC #4 
is forced to be HIGH> selecting Bank #2* IC 
#2 and IC #3 make sure that no bus conflicts 
occur while you are bank-switching* Note that 
whenever you access the region 
«B000~»BFFFf Bank #1 will always toggle 
back into its place* 

I hope that you have §§iimd some new 

knowledge on this topic and utilize it in your 
next project* HAPPY HACKING! 

REALLY USE YOUR 
ATARI! 



Q: What's the unpleasant monthy 
task that could easily be 
computerized? 

A: Balancing the bank statementi 

Get CHECKBOOK CHECKER- 

*So simple to use, it overcomes 
spouse's computerphobia. 

* Fewer steps than usual — 

Let the computer do the work! 

* Fully prompted by TV screen. 

* Specialized for home checkbooks. 

* Unusual features such as 
indepencbnt odder, to find errors. 

*ldMl biHfiday or holiday gift: 
Useful— cmct virfiat a pricel 

Atari, 32K min.. Printer optional. 
Disk $9.95 Postpaid 
(NJ residents odd 6% tax.) 

PRINCETON COMPU-CENTW 
ASSOCIATES 
119 Jefferson Rood 
Princeton, NJ 08540 




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10 




SATURDAY 



10 




ZERO 
by Ann McBain Ezzell 

MACE members come in m«y varieties» from 
absolute novices ("How do you get this thing 
out of the box?") to veteran hackers ("Connect 
the frim-fram to thromiiibulator» and away you 
go!")» We obviously can't meet everyone's 
needs, but here is the latest attempt? a 
column for beginners* I will assume that you 
have figured out how to open the carton 
get all the assorted parts plugged in and 
humming » and are now ready to tackle some 
progra^iimnt* TMs months I will talk a bit 
about computers and numbers so that you 
won't look . totally bewUdered when your 
friends st^ rattling on about bits and bytes 
and hexadecimal notation* 

First, let's think about the sort of numbers 

most of us use all the time* 0, 1, 2, 3, and so 
on« He have ten digits (0 through 9)» and can 
count up to nine objects using just one digit* 
Once we hit ten, however, we switch over to 
two digits* 10* This means (reach back into 
your grade school memories) mro ones and one- 
10* Using two digits, we can count up to 99 
objectSf then we need to add another digit^^or 
one hundred or more* 100* This means one 
100, zero lOs and zero ones* 100 is equal to 10 
X 10» which cat) also be written 10'^2 (ten to 
the second powerrW ten squareiik 1000 is t6 
X 10 X 10, or ten to the third power (10"-3)* 
You can see that each "place column" 
represents a ptmer of ten* We call ttuM 
number system "base ten"* 

Base ten is fine to use if you have lots of 

fingers handy for keeping track of things, but 
what about a computer? It deals in electrical 
voltages^ and its basic compomnts^^M^only 
handle two states? high and low (which we will 
call 1 and 0)* So how many numbers can we 
express using just two digits? It's ob%ious» 
isn't it? Just two* zero and one* If we want 
to write the number two using this binary 
notation > we will have to use "10"# which i» 
one 2 and zero ones* Using two binary digits, 
we can express four different numbers* 00 
(zero)» 01 (one)» 10 (twc^ and U (three)* Soto 
get to the number four, we would have to add 
another digit* 100* Four is equal to 2 x 2# or 



2-^2* The next digit added would be 2'^3 or 2 x 
2 X 2# which is eight* So the number eight in 
bifivy iMitation would be written* 1000* 

Now, a brief detour to the nomenclati^ 
departments My trusty dictionary definM « 
bit this way* "In information theory, a unit 
equal to the information content inherent in a 
choice bet«MM»n two equally probable 
alternative messages or symbols, as between a 
'yes' and a 'no' or a dot and a dash"* It is 
cterived from the words "btinary) (diig)it"# For 
our purposesf think of a bit as being eitherm 
one or a zero* one of the digits in a binary 
number* 

You may have heard the Atari referred to as 
an "eight-bit machine"* This means that the 
Central Processing Unit (CPU) can handle 
information in eight bit chunks (these chunks 
are called bvtes )* How large a number can we 
express using eight bit9?-^ne- digit fiiill give 
us two numbers (zero and one), which is 2^^!* 
Two digits gives us four numbers, or 2'^2J 
three digits gi^ us eight tl'^tsih With eight 
digits, then, we should be able to express 2'''3 
different numberst Two to the eighth power 
equals 256, but remember that mm start with 
zero, 50 a byte can be anything from 0 to 255* 

To express numbers larger than 255, you have 
to use more than one byte* If you have done 
much reading about your Atari, you may seen 
references to "high** and "low" bytesf w Jtost 
Significant Byte (MSB) and Least Significant 
Byte (LSB)* When two bytes are used to 
express a numbert one represents tMe^^^noes 
column" and the other represents the "256s 
column"* This latter byte is the "high" or 
Most Significant Byte* To convpit sycb^ 
number to decimal (base 10) notation, yd& 
would take the value of the high byte and 
multiply by 256$ then add the value of the low 
byte* 

High byte « 54 
Low byte = 6 

Decimal equivalent =256*54 + 6 = 13830 

To convert a decimal number into its high and 
low bytes, divide the number by 256 and take 
the integer (whole number) part, which is the 
high byter T^Pa^^^B is ttanncMnber ifimis 
256 times the high byte* 



53674 / 256 = 209*664 
High byte = 209 
5^74 - 256*209 - 170 
Low byte « 170 

The Ai^yri usually stores ^ufnterm f renter 

256 in two consecutive addresses* with the lo^ 
byte stored first* You will often see 
sometM^g like this in prag^mmt^ 

100 SCREEN = PEEK(88) + 256 * PEEK(89) 

Locations 88 and 89 together hold the address 
of the screen display memory* This program 
line fetches the low and high bytfiH» and 
combines them to be stored in ttie ¥iriiMe 
"SCREEN"* 

Binary notirttoff may be^ftwi for the^wmputer, 
but it's rather cumbersome to use* Who wants 
to write "01100110" for the decimal number 
102? Alsot converting betwem dedfnal and 
binary can be awkward* There is another form 
of notation which is often used with 
computers* hexadecimal* Tbe^^^tymologists 
among you will immediately realize that this 
system uses 16 as a base» just as decimal uses 
10 and binaryt 2* But wai^' Hhat are we going 
to use for digits if we have to express 
numbers up to 15 using only one digit? Hex 
notattovt^ tisM 4rNP^aettei*:^dN^ BdEor 
decimal 10 through 15* 

Using only two hex dig^r «Mr<w express any 

number up to 255 (hex numbers are often 
prefixeci with a to differentiate them from 



0 


$00 


10 


«0A 


16 


$10 


92 


*5C 


255 


*FF 



To convert between hex and decimal* just 
remember that the rightmost column in a hex 
number is the ones column * and the next column 
is the 16s column* A four digit hex number 
also has a 2S6s column (16'^2) and a 4096s 
column (16'''3)* Four digit hex numbers can be 
broken into high and low bytes (the high byte 
being the two lefthand digits) for easy 
^MiPersiariifeititecimal notaticm* 



One more new word* and I will lei^e you to 

digest all of this until next month* The word 

is nvbble* which is (what else?) half of a byte* 
Think of the hra^^iMrtetion for a bytei it has 
two digits^ each of which is a nybble (high and 
lowf left and right)* Thinking of bytes in 
terms of nybbles makee cmimrsion between 
binary and hex a cinchj divide the eight bits 
into two sets of four and convert each into a 
eumber from 0 to E (dec2mi^#oto 15)f 

For example# take the binary number 01011100* 
Divide it into two sets of fouri 0101 and 1100* 
The first set is equivalent to 5 (zero Ss^ one 4, 
zero 2s» and one 1)» the second equals 12# or C« 
Therefore^ this number can be iMPiMen in hex 
notation as *5C* 

So there you have it! bits» bytest an^j^ibblesj 

decimal, binary and hexadecimal notation* I 
hope that this will help you in your Atari 
explorations^ and I'll be back nci^^iMfithi^^Afiy 
suggestions for future columns should be sent 
to me at the MACE PO Box# 




by John J * Marhevko 



The day that my Atari 810 disk drive broke 
down I thought OH NO! I bet it will cost at 
least $25*00 just for someone to look at itt 
plus some more money if some part went bad* 
And then I'm without my disk drive for 
probably a week or two* GADZOOKS!!! No 
playing Pac Man for me or word processing for 
the kids doing their school work! 

With a little common sense and thinking I tried 
another power pack* Sure enough^ the only 
thing that went bad was the {Miwer padiir J^t 
now I would have to buy a new one for *20*00! 
Here's thanks to the nice people at Rite-Way 
who told me to open the bottom of the power 
pack with a screwdriver and check the fuse* 
Sure enough, the fuse was burned out» It took 
me only ten minutes to go to the store and buy 
a 35 cent fuse and put the whole thing back 
together* Now the world is safe again because 
I'm back to killing all those nasty oc^atyrtm on 
the TV* 



ALL ABOARO! 



Sometimes all the functions on a bulletin board 

can be confusing, especially if it's your first 
trip across the wires* You are faced with a 
long list of tetterst no idea of what each 
does* (No, "A" does not stand for 
"AAAARRRRRGGGGHHH!!!") Most AMIS 
format boarcte use more or less the same 
functions, so here is ttm help file frtm MACE 
West (313-582-9^57) to get you started* - 1 

A - ASCII/AT ASCII switch* (Ganges -contarol 
character sets between ASCII and ATASCII* 
To use> fequest 'A'> set your terminal program 
to AT ASCII and when you are returned to the 

BBS, press <RETURN>* 

B - Bulletin reprints the bulletin sent at 
log-on to MACE Wi8T» 

C - Configuration of system* Describes major 
pieces of #c|Mi(iii)fmt currently used to run this 
board* ^ 

D - Download file* Send a program to you* 
Use this function in ATASCII mode, or inverse 
text will not be sent cxMrrectly* If unsure of 
XMODEM protocol, respond 'N'* All BASIC 
files are in LISTed format* 
E - Enter a rrfessage into MACE WEST# 
Pressing 'Q' after entering a message will 
abort the message* Other 'E' subfunctions are 
self-explanatory* - 
F - List files that may be sent with the 'D' 
(Do%mload) f4Jni;;t;U}nf Files are in double 
density so they are actually twice as large as 
they appear* 

G - Goodbye* Exit from MACE WEST. 
H He^t^*r*it» t*ii«^^iist# 
I - Index of download files* A very short 
description of programs available in the 
Dowiload f iles« -'^ 
K - Kill a message* Use this to delete a 
message from the file* A password may be 
necessary if one was used at message entry* 
The sysop will kill a message with a forgotten 
password if a message is left at log -off* 
L— Line feed on/off* Normally off* For 
terminals that need an extra line feed to 
advance the line* 

M l^si^ basei Use commands Ef Qt Ri and 

S within this subsystem* Using 'M' within the 
message base will return you to the main 
menu* 

N - News* Contains club news and interesting 



articles from outside sources* 

O - Other Ati^ BBSs listed by area code* 

Q - Quick scan* An abbreviated scan* PfMits 

only the subject of the messages* 

R Retrieve messages* Allows you to read 

messages contained in the message base* 

S - Short scan* Prints the name of message 

Mffdert tlie ifftamted^^peofMiitr subject hea^i^ 

and date of the message* 

T - Time and date* Gives you the current time 
and diAet 

U - Upload* Use to upload a file to MACE 
WEST from your terminal* If unsure of 
XMODEM protocolf answer 'N' to the prompt* 
W - Welcome* Reprints the welcome message 
sent at log -on* 

X ^ Expert user* Shortens some system 
prompts* 

Y - Yell for system operator for chat* 
? - Short list of BBS commands* 

CTRL<S> Pauses the display* ' 
CTRL<Q> Continues the display* 
CTRL<N> Goes oif t0 the fi«t message* 
CTRL<X> Aborts current send* 




Paul Wheeler reports that he has had calls 
asking aliout the possibility^ of forming a 
morning or afternoon SIG group for MAGE 
members who work the second and/or third 
shift and can't make it to the regular evening 
meetings* If you are interested in surt-m 
groupf send your name, address and phone 
number to the Journal Editor at the P*0* Box, 
or leave the information in the Suggestion Box 
at a meeting* ^ 

CC»€INGSOON! 
MACE BBS will be revving up to 1200 bps in 
the near future* No more dreary slo-mo 
downloads for you speed demons* 

Effective March 19th, certificates for free 
program d i etee/ tapes will only be honored for 
60 days from the date of issue* If you have 
some old ones hanging around, trade them in 
now* Also please remember to bring your 
MACE membership card when you pt^c*iee# 
from the libraries; they are open to MEMBERS 
ONLY* 



OCMOOElyE FILE 

TRAlSCS]Fp3R I=*ROTOCOL. 

By Larry Jordan 

[This article was derived from material 
contained in a book written by Larry Jordan 
and Bruce Churchill to be published Summer '84 
by The Brady Company* This article was 
downloaded from thst G#T*I#A# BBS in 
Kitchener, Ontario, Canada* Our thanks go to 
Steve Gauthier and the gang in tJw greatjwhite 
mrth! -Ed»2 

Wtmn transferring files between computers 
using the telephone system, there is always 
the chance that electrical noise will result in 
data transmission errors* To ensure proper 
transfer of files it is necessary to detect data 
transmission errors and to retransmit data 
that contains errors* Most people think that 
asynchronous parity error detection provides 
that capability* It does not* Parity error 
detection does tell you when a data transfer 
error has occurred, but it is up to you to 
retransmit the data to correct errors* The 
problem is that parity error detection is not 
actually performed by most ATARI 
communication packages* If a package does 
perform the error detection* it may not inform 
you of errors in such a way that you know to 
immediately retransmit the data* To ensure 
"error-free" data transfer ^ou l^eed |i protocol 
fil# trwsfer ^ME^iquet 

A protocol is a set of rules and conventions 
that apply to a specific area of communicaticms 
that allow participants to properly 
.communicate regayrdless of the hardware brand 
or software package being used* The protocol 
file transfer is a set of rules for transferring 
files which specifies a set of ASCII 
handshaking characters and tte scNiiuence of 
handshaking required to perform certain file 
transfer functions* Protocol handshaking 
signals allow communication software to 
transfer text, data and machine code files, and 
to perform sophisticated error-checking* The 
handicap in using protocol file transfer 
techniques is that the computers on both ends 
of the communications link must be using 
compatible saftmrnmi there is no standard that 
controls these protocols and almost all 
communication packages that haye a protocol 



file transfer option use a protocol unique to 
that package* This means that a business or 
group of people mmt standardize its 
microcomputer communications software to 
take advantage of protocol transfers* 

The Ward Christensen XMODEM protocol is 
one specific file transfer protocol that may 
become a default standard in personal 
communications because of its widespread use 
on bulletin boards and because of its inclusion 
in low cost personal computer communicatioii 
packages such as AMODEM 4*2* It has not 
gained widespread acceptance in business 
communication packages partly .tecause the 
protocol is public domain; most business 
communication package designers use unique 
protocols to force businesses to use their 
software on both ends of communication links* 
By providing you with this insight into 
protocol transfer and explaining in detaU the 
operation of the XMODEM protocol, I hope to 
add momentum to the development of a 
"standard protocol" whet^r it ise the 
XMODEM model or some other model* Vsi^ of 
communication software deserve a standard 
protocol that will aUow them to use the 
technique with any microcomputer regardles of 
the software packages employed* 

TJie XMODEM protocxd is illustrated in Figure 

1 * As you can see from that figure, XMODEM 
does not begin thf transfer of data until the 
receiving oamputer signals the transmitting 
computer that it is ready to receive data* The 
Negative Acknowledge (KAK) character is used 
for this signal and is sent to the transmitting 
computer every 10 seconds until the file 
transfer begins* If the file transfer does not 
begin after 9 NAK's are sent# the process has 
to be manually restarted* 

After a NAK is rB&dmdlf th^ t^^ 
computer uses a Start of Header (SOH) 
character and two block numbers (a true block 
number followed by a Ts complement of the 
number) to signal the start of a 128-byte block 
of data to be transferred then sends the block 
followed by an error-checking checksum* The 
checksum is calculated by adding the ASCII 
values of each character in the 128 character 
block, the sum is then divided by 255 and the 
remainder is retained as the checksum* After 
each block of data is transferred, the 



receiving computer computes its own checksum 
and compares the result to the checksum 
maBiym4 from the transmitting cx»mputer« If 
the two values are the same^ the receiving 
computer sends an Acknowledge (ACK) 
character to tell the receiver to send the next 
sequential block* If the two values are not 
the samet the receiving computer sends the 
transfmtter an NAK to reqpjest a 
retransmission of the last blodCf TMs 
retransmission process is repeated until the 
blodc of data is propmrly received or until 9 
attempts have been made to transmit the 
block* If the communications link is noisy# 
resulting in improper block transmission after 
9 attempts^ the file tr^mfmr is aborted* 

XMODEM UMS t¥iO block numliiNrs at the start 
of each block to be sure the same block is not 
transmitted twice because of a handshake 
dharmibm^ Mia» during the transfer* The 
receiving computer checks the transmitted 
block to be sure that it is the one requested 
ifid blocks that are retransmitted by mistake 
are thrown away* When all data has been 
successfully transmitted » the transmitting 
Gsm^^MT sends the receiver an End of 
Transmission (EOT^^cftaracter to indicate t»ie 
end of filet 

The XJKKDEM protocol offers the Atari 

several advantages over other protocols and 
file transfer methods* First, the protocol is 
in the public domain which makes it readily 
available for software designers to 
incorporate into a communications package* 
Second, the protoGcd is^SMy ts ^mplMWiit 
using high level languages such as BASIC or 
Pascal* Third* the protocol only requires a 
256-byte comiminicatlon tscet^ buffer which 
makes it attractive for Atari owners* Fourth, 
the protocol allows a user to transfer 
non-ASCII 8-bit data files (i*e*, OBJ, SXE^ 
tokenized BASIC) between microcomputers 
because it calculates the end of a file based on 
file size and uses h^dshake signals to 
indicate the end of a file instead relying on an 
end of file marker character (control-Z) to 
terminate a file triMflsfer* Fifth, XMODEM 
error-checking is superior to normal 
asynchronous parity error checking* The 
parity method of error-checking is 95% 
effective if the software on the receiving end 
checks for parity errors* XMODEM 



error-checking is 99*6% effective, and the 
software on the receiving end must check for 
errors* Parity errors detected also do not 
result in automatic retr«smission of the bad 
data; XMODEM detected errors result in data 
retransmission until no errors are detected or 
until* 9 retransmissions have been atterrnited* 
Finally^ the protocol is used by many bulletin 
boards and having the protocol in a 
communications package allows the Atari user 
to receive error-checked files from these 
boards* 



XHQDEH Protocol file Transfer 



Receiving 

Cortputer 

Readiif to 
Receive 
f 



TransHitting 
CoMputer 
Read^ to 
Transiiit 



I 

I 

\ 

</Si]H/Blkl/Blia/Good/CkSuH/ 
I 

I \fiCK\ 

\ 

</SaH/BU(2/Blk2/Good/CkSuN/ 
I 



•\ACK\- 



I 

</9ai/Blk3/Blk3/M/OtS»i^- 
f 



■Mm- 



</S0H/BlK3/Blk3/Good/CkSuH/ 
I 



•\ACK\- 



I 

<■ 
I 

I- 
I 



■/EOT/- 



•\ACKV 



File 
Receipt 
Ends 



File 
Ends 



Figure 1 



BULLETIN boards: MACE 978-1685/MACE WEST 582-0657 
MACE HOTLINE (Information - Voice Line) 882-7104 



PRESIDENT 
Kirk Revitzer 
Detroit 
882-9109 
Compuserve: 70346»1642 
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552-0273 

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535-3748 
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PROGRAM COORDINATOR 
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851-9453 

RECORDING SECRETARY 
Dino Roggero 

Redfbrd 
BBS: 531-1701 



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Mike Landis 
Claw son 
589-1789 
Compuserve: 72675*1023 

M>A,C,E. JOURNAL EDITOR 
Ann McBain Ezzell 
Birmingham 
646-4455 



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