Table Of ContentMastering the TI-99
Mastering the
TI-99
Peter Brooks
^e/ MICRO PRESS
Firstpublishedin1984intheUnitedKingdomby
MicroPress
CastleHouse,27 LondonRoad
TunbridgeWells, Kent
© CastleHousePublications1984
Allrightsreserved.Nopartof
thispublicationmaybereproduced,
storedinaretrieval system, or
transmitted,inanyformorbyany
means,electronic,mechanical,recording
orotherwise,withouttheprior
permissionofthe publishers.
BritishLibraryCataloguinginPublicationData
Brooks,Peter
MasteringtheTI-99.
1. TexasTI-99(Computer)
I. Title
001.64'04 QA76.8.T/
ISBN0-7447-0008-6
Typesetby KeysetComposition,Colchester
PrintedandboundbyMackaysofChathamLtd
Contents
Acknowledgements vi
Chapter1 Introduction 1
Chapter2 Translation 3
Chapter3 Jargon 26
Chapter4 FileHandling 40
Chapter5 GraphicsandPlotting 51
Chapter6 PrintingErrors 82
Chapter7 Hints andTips 90
Index HI
Acknowledgements
I owe thanks to more people than Icould mention, but Iwould
like gratefully to acknowledge the assistance of the following
people during the period leading up to the preparationof this
book:
Elizabeth, for putting up with the incessant chatter about
computers; my parents, who aided me in the purchase of my
equipment; Paul Dicks, for having patiently endured endless
telephonecallsoverthelastthreeyears,forhavingallowedmeto
shootmy mouthoffinpublicthrough thenow-defunctTidings,
and forhavingplacedme in aposition towritethis book; Trevor
Hood, ofCastleHouse, for commentsandinvaluablehelpin the
production of the manuscript; Matthew Childs, for having
checked some of the routines for me; George Moore, for
constructive criticism during editing and proofing; and anyone
whoeverhadasoftwareproblemandbroughtittome—Ialways
found the experiencebeneficial.
PeterBrooks
Oxford
October1983
Introduction
For thenewcomer,homecomputingcanbeaveritablequicksand
ofjargonandstrangeconcepts. Confusionandfrustrationare the
two mostcommonconditionssufferedbythosewhohave'taken
the plunge', bought a home computer, and are engaged in a
desperate struggle to understand their machine and its manual,
and perhapseven to find a practicaluse forit. (These conditions
seem tobe experiencedmore severely in the U.K. byTI-99/4and
99/4A owners, because the machine appears to be marketed in
Europewith theAmericanconsumerin mind.)
Theirefforts are hampered by comparatively minor problems
—printingerrorsoromissionsinmanuals,books,ormagazines,
for example— and often the solutions, when uncovered, are so
simpleas tocausemuchsmackingofforeheads andutterancesof
self-deprecation.
Even after struggling through the early stages, however, the
difficulties are not reduced, as attempts are made to translate a
program written for one machine, in a supposedly 'common'
language, intoTIBASIC.
You have become the owner, possibly proud, of a Texas
InstrumentsHomeComputer. Ifyouboughtyourmachinesome
time ago, you will already be aware that it has a number of
annoying deficiencies when compared with its competitors. In
the majority of cases, these can be overcome through careful
programming, some examples of which are presented in this
book. In others, sadly, the only alternative is to keep throwing
money at the problem(s) by buying more and more equipment,
whichcan oftenresultinyourbeingable todo less thanbefore.
There are two things to bear in mind when close to capitu
lation: firstly, that there is NOTHING which cannot be under
stood byyou eventually; ifan explanation doesn't'click', that is
notyourfault. Eitherask, ifyou can, forit to be re-expressed, or
lookelsewhere for enlightenment. Secondly, perseveranceis the
2 MasteringtheTI-99
name of the game. No matter how intractable the problem may
appeartobe,someone,somewhereeitherhasthe solution,orcan
pointyouintherightdirectiontowardone.
Become a memberofalocalcomputerclub if there is one, and
joinone(ormore)ofthespecialistgroupswhichcaterspecifically
for theTI-99/4and99/4A.Readcomputermagazinearticles,even
if you don'tentirely followthem, and don't restrictyoursubject
matter to the TI computer alone. Tricks on other machines may
not be directly applicable to the Texas computers, but they can
triggerideaswhichendupasusefulroutinesortechniques.
Keep on coming back to programs or ideas which you have
worked on in the past: you'll find that the experience gained in
just a few weeks can help you to improve on whatwent before,
evenhighlightingerrorswhichyoumayhavemissed.
Aboveall, ifyou think thatyou havefound somethinguseful,
interesting, or even staggeringly amazing, don't keep it to
yourself. Discussitwithfellowowners,writetomagazinesabout
it, butneverthinkthatit is unimportant. Evenifitdoes turnout
to be so, you will still have learned something, and that is most
important.
This book lies somewhere between a vast tome of totally
understandable explanations, and a packed, incomprehensible
reference work, and as such is of necessity something of a
compromise. The one thing it cannot do is to answer every
question that TI owners might pose, so if you have anything
which you would like to discuss, any questions that you would
likehelpinanswering,Iam happytoacceptanycorrespondence.
You can contact me via the publisher, CASTLE HOUSE, but
pleaseincludeastamped,self-addressedenvelope.
And finally, ifDarthVaderon the front cover resemblesme, it
is purelycoincidental!
Translation
The task which many newownersmostoften undertake is to try
to translateintoTIBASICaprogramwrittenforanothermachine
and publishedinabookor magazine.
AlthoughBASICisacommonlanguage, you mayalreadyhave
realised that there is BASIC, and then there is BASIC. There are
almost as many dialects of BASIC as there are machines, and
although each dialect has its origins in the early American
'Dartmouth' BASIC, each has been added to and 'improved' in
order to enhance the facilities available. Translation from one
dialect into another can be fraught with difficulties, because of
subtle language differences and printing errors or omissions in
the publishedmaterial. Sometimestheonlyalternative togiving
up is to buy theowners'manual forthe machineconcerned, and
attempttousethatas asourceofreference. The problemis thatif
you use that approach you could end up with hundreds of
manualsandstillno translatedprogram.
This chapter looks at some of the more common BASIC
reserved words which are used on other machines, and, where
possible, gives the alternatives which TI BASICcan employ. It
also gives some suggestions on how to cope with some of the
'constructions' used in other BASICs: for example, 'IF A = B
THENC = D'or'IFA = BTHENPRINT"HIT'".
In addition there are differences between the 99/4 and 99/4A
which need highlighting, especially in respect of the keyboard
and keycodes, and, toalesserextent, thevariablenames.
To beginwith,wewilllookatsomeofthecommandswhichare
likely to be found in published listings of programs written for
other machines. There are certain commands which cannot be
implementedinTIBASICwithoutadditionalequipment—some
uses of PEEK and POKE, for example — and unless you are
particularly adventurous or masochistic it is best to avoid those
programswhichmakeuseofmanyPEEKsorPOKEs,especiallyif
