Oakland CPM Archive/oakcpm.iso/cpm/gendoc/ucpm10.ark/PART1.STR

Text File | 1988-02-01 | 19.8 KB | 478 lines

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                            THE UCPM MANUAL



                 General Information on CP/M Computers
                            for Programmers



                              version 1.0
                        released 1 February 1988



                              compiled by
                            Ted A. Campbell

                         based on contributions
                      from the CP/M user community




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                           Table of Contents



Part 1:  Introductory Materials

     Preface
     The Prospects for CP/M Software Development
     Strategies for Overcoming Compatibility Problems

Part 2:  CPU Survey:  Information on Basic Computer Hardware

áááááAltai≥ 880░ (MITS)
áááááAlto≤ 8000-10
áááááAmstrad CPC 6128
áááááApple ][ with PCPI Applicard
áááááApple ][ with Microsoft Softcard I
áááááBig Board I
áááááCromemco Z2D
áááááCompupro
áááááEpson PX-8 "Geneva"
áááááEpson QX-10
áááááA Homemade System
áááááKaypro II modified to Kaypro 8
áááááMultiflex
áááááNorthstar Advantage
áááááOsborne 1
áááááOsborne Executive
áááááStride 440
áááááSord M-68
áááááTektronix 4132
áááááTelevideo TS803
áááááVisual Technology 1050


Part 3:  Terminal Survey:  Information on Terminals and
         Video Displays

áááááAmstrad CPC 6128
áááááApple ][
áááááApple ][e with Microsoft Softcard I
áááááDEC VT-220
áááááEpson PX-8 "Geneva"
áááááEpson QX-10
áááááKaypro '83 series
     Kaypro '84 series
áááááKimtron (PC Shadow)
áááááMultiflex Video Card
áááááNorthstar Advantage
áááááOsborne 1
áááááOsborne ExecutiveèáááááTelevideo TS803
áááááVisual Technology 1050 = ANSI
áááááZenith Z19

     Appendix to Part 3:  Comparative Table of Escape Sequences


Part 4:  Disk Format Survey:  Information on Disk Formats

áááááAltos Double Density
áááááAmstrad System Format
áááááAtari CP/M Format
áááááApple CP/M
áááááApplσ Disδ II
áááááCromemco Z2D and Cromemco DSDD
áááááEpson QX-10
áááááGeneric CP/M (8")
áááááExchange Format (8")
áááááKaypro DSDD
áááááMultiflex Format
áááááNorthstar Format
áááááOsborne SSSD
áááááOsborne SSDD
áááááStride 640K Format
áááááSunswick Engineering 5-640
áááááSord Format
áááááTelevideo TS802/TS803/TPC
áááááVisual Technology Proprietary Format


Par⌠ 5║  Referencσ Material≤ fo≥ Genera∞ CP/═ Programming

     1«  CP/═ BDO╙ AN─ BIO╙ ENTR┘ POINTS

          BDOS
          BIOS

     2«  Referencσ Informatioε fo≥ StandarΣ CP/═ Assembly
         Languagσ Tools

          ASM
          LOAD
          DDT
          MAC
          LINK
          SID

     3«  Referencσ Informatioε fo≥ Microsof⌠ BASIC


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                                PART 1:

                         Introductory Materials



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                                Preface


     Thσá UCP═ manua∞ attempt≤ t∩ providσ basiπ informatioε fo≥ programì
mer≤ oε ß rangσ oµ CP/═ computers«á  Thi≤ i≤ it≤ firs⌠ release¼á anΣá wσ ì
hopσá tha⌠á thi≤ releasσ wil∞ encouragσ other≤ t∩ completσ surve∙á form≤ ì
and correct or complete information in the manual.

     Thσá informatioε supplieΣ iε thσ manua∞ ha≤ beeε collecteΣá largel∙ ì
froφá thσ comp.os.cpφ newsgrou≡ oµ Usenet¼á althougΦ somσá surve∙á form≤ ì
werσ collecteΣ froφ othe≥ sources¼á sucΦ a≤ thσ CP/═ Foruφ oµ GENIE¼ anΣ ì
local Bulletin Board Services.

     T∩á m∙á knowledge¼á al∞ oµ thσ informatioε iε thσ manua∞ i≤ iεá thσ ì
publiπ domain¼á anΣ ╔ hereb∙ releasσ thσ text¼á t∩ thσ exten⌠ tha⌠ i⌠ i≤ ì
m∙á owεá work¼á int∩á thσ publiπ domain«á  Thi≤ mean≤ tha⌠á yo⌡á caεá d∩ ì
anythinτ yo⌡ wan⌠ witΦ i⌠ excep⌠ sel∞ it«á  M∙ hopσ i≤ tha⌠ thσ completσ ì
ucpm.arπ filσ wil∞ bσ uploadeΣ t∩ Bulletiε BoarΣ Services¼ networks¼ anΣ ì
other repositories where it can be available to CP/M programmers.

     ╔á wan⌠ t∩ thanδ al∞ oµ thσ CP/═ user≤ wh∩ havσ contributeΣá surve∙ ì
forms«á  Thi≤ worδ i≤ possiblσ becausσ oµ thei≥ help«á  ╔ woulΣ likσá t∩ ì
thanδ KeitΦ Petersoε fo≥ transferrinτ surve∙ form≤ froφ thσ GENI┼ systeφ ì
t∩á Usene⌠á s∩ tha⌠ ╔ coulΣ acces≤ theφ withou⌠ runninτ u≡ m∙ owεá GENI┼ ì
bill« á Thank≤ als∩ t∩ RicharΣ Conn¼ froφ whosσ HEL╨ file≤ mucΦ áoµ áthσ ì
materia∞ iε Par⌠ ╡ oµ thi≤ worδ i≤ derived.

     Again¼á iµá yo⌡ havσ furthe≥ information¼á o≥á suggestions¼á pleasσ ì
forwarΣ theφ t∩ me║

          [e-mail]

Happy computing!


- Ted A. Campbell
  President,
  Raleigh Other Computer Club

.paè
.he UCPM Manual, Introductory Materials, Page #

              The Prospects for CP/M Software Development


     Tw∩á o≥á threσ year≤ ag∩ CP/═ wa≤ describeΣ a≤ ßá "deadóá operatinτ ì
system¼ anΣ i⌠ wa≤ laregl∙ presumeΣ tha⌠ furthe≥ developmen⌠ iε thσ CP/═ ì
areßá haΣ o≥ woulΣ sooε cease«á  An∙ surve∙ oµ recen⌠ release≤á oµá CP/═ ì
softwarσ wil∞ falsif∙ thi≤ presupposition«á  However¼á thσ prospect≤ fo≥ ì
CP/═á developmen⌠á arσá changing¼á anΣ wσ shoulΣ takσá notσá oµá curren⌠ ì
trends«

     I⌠ ha≤ beeε estimateΣ tha⌠ therσ arσ betweeε onσ anΣ ß halµ anΣ tw∩ ì
millioε CP/M-baseΣ computer≤ iε existence¼ roughl∙ divideΣ betweeε Applσ ì
CP/═á anΣ othe≥ CP/═ system≤ (seσ Robiε Nelsoε anΣ DaviΣ Needle¼á "CP/M║  ì
Stil∞á thσ Olº Workhorse,ó Persona∞ Computingé 9:╖ [Jul∙á 1985]║á 54-65)«  ì
A⌠ leas⌠ threσ CP/═ compatiblσ system≤ arσ stil∞ iεá production¼á namel∙ ì
thσ Micromin⌠ SB180¼á thσ Commodorσ 12╕ anΣ thσ AmstraΣ PC╫ series«  Onσ ì
caεá arguσá that¼á sincσ CP/═ machine≤ arσ n∩ longe≥ beinτá produceΣá iε ì
impressivσá numbers¼á thσ prospect≤ fo≥ softwarσ developmen⌠ mus⌠ no⌠ bσ ì
good«á  Whilσ mos⌠ woulΣ admi⌠ thσ trutΦ iε this¼ thσ fac⌠ i≤ tha⌠ olde≥ ì
CP/═ machine≤ arσ beinτ maintaineΣ anΣ passeΣ oε t∩ ne≈ users« Onσ woulΣ ì
suspec⌠á tha⌠ a⌠ leas⌠ onσ halµ oµ thσ existinτ CP/═ machine≤ arσá stil∞ ì
iε use«

     ┴á bette≥á estimatσá oµ thσ curren⌠ marke⌠ migh⌠á bσá gleaneΣá froφ ì
curren⌠ sale≤ oµ CP/═ relateΣ softwarσ products«á  Wheε MicroPr∩á Interì
nationa∞ Corporatioε recentl∙ decideΣ t∩ marke⌠ aε upgradσ oµ thei≥ CP/═ ì
Wordsta≥á (tm⌐ product¼á the∙ attempteΣ t∩ determinσ witΦ morσ precisioε ì
thσ sizσ oµ thσ use≥ community¼ bu⌠ werσ unablσ t∩ d∩ so«  B∙ contactinτ ì
thσá Firs⌠ Osbornσ Grou≡ (FOG⌐ anΣ othe≥ Use≥á Groups¼á the∙á determineΣ ì
tha⌠ thσ projec⌠ woulΣ bσ feasible«  ┴ MicroPr∩ Marketinτ Communication≤ ì
Manage≥á workinτ witΦ thσ CP/═ produc⌠ stateΣ iε ß lette≥ t∩ mσ tha⌠ thσ ì
compan∙á solΣ 17,00░ CP/═ upgrade≤ betweeε Augus⌠ anΣ Novembe≥á oµá 198╖ ì
(thσá produc⌠á wa≤ releaseΣ iε August)«á  MicroPr∩ expect≤á t∩á continuσ ì
sellinτá upgrades¼á althougΦ the∙ arσ realistiπ iε projectinτ tha⌠ sale≤ ì
oµá thσ CP/═ upgrade≤ wil∞ dro≡ ofµ afte≥ aε initia∞ surgσ oµá interest«  ì
Sale≤á oµ othe≥ CP/M-relateΣ product≤ confirφ thi≤ pattern«á  ╔ recentl∙ ì
spokσ b∙ telephonσ t∩ ß representativσ oµ Echelon¼á Inc.¼á whicΦ market≤ ì
thσ ZCPR│ commanΣ processor¼á ZRDOS¼ anΣ othe≥ products«  The∙ explaineΣ ì
tha⌠ afte≥ aε initia∞ surgσ oµ interest¼ sale≤ haΣ declineΣ slowly«

     Wha⌠á thi≤ mean≤ i≤ tha⌠ therσ i≤ ß communit∙ oµ user≤ wh∩á welcomσ ì
moderately-priceΣá ne≈á softwarσá tha⌠á wil∞á ruεá oεá thei≥áá machines«  ì
MicroPr∩ correctl∙ identifieΣ use≥ group≤ a≤ thσ mos⌠ promisinτ mean≤ oµ ì
gettinτá t∩ thσ use≥ community«á  Softwarσ developer≤ caε expec⌠ t∩ finΣ ì
initia∞á interes⌠á higΦ iµ the∙ arσ ablσ t∩á publicizσá thei≥á products«  ì
However¼á the∙á canno⌠ coun⌠ oε continuinτ interest«á  Onσ suspect≤ tha⌠ ì
therσ arσ pricσ threshold≤ tha⌠ coulΣ bσ exploiteΣ (releasσ thσá produc⌠ ì
a⌠ ß giveε price¼ theε wheε enthusiasφ flag≤ brinτ thσ pricσ dowε t∩ thσ ì
point where another group of users might purchase it, etc.).

     Giveε thi≤ genera∞ picture¼á onσ doe≤ no⌠ expec⌠ mucΦ iε thσ wa∙ oµ ì
commercia∞ developmen⌠ iε thσ CP/═ area¼á howeve≥ thankfu∞ wσ arσ wheε ß ì
produc⌠á likσ Wordsta≥ i≤ revised«á  Oε thσ othe≥ hand¼á privatσ public-ìèdomain¼ shareware¼ o≥ "use≥ supportedó softwarσ ha≤ alway≤ beeε prolifiπ ì
iεá thσá CP/═á area¼á iε somσ case≤á positivel∙á hinderinτá attempt≤á a⌠ ì
commercia∞á developmen⌠ (i.e.¼á wh∙ bu∙ ß modeφ prograφ wheε yo⌡ caε ge⌠ ì
ME╪ o≥ IMP╗á wh∙ bu∙ ß tex⌠ edito≥ wheε yo⌡ caε ge⌠ VDE¼ etc.)«  A≤ lonτ ì
a≤ person≤ witΦ programminτ interest≤ owε CP/═ computers¼ onσ caε expec⌠ ì
a trickle if not a stream of new development.

     Bu⌠á thi≤á raise≤ ß crucia∞ problem«á  CP/═á developer≤á arσá ofteε ì
frustrateΣá becausσá timσ spen⌠ developinτ ß prograφ fo≥ onσ machinσá i≤ ì
ofteεá no⌠ translatablσ int∩ workinτ version≤ oµ thσ softwarσ fo≥á othe≥ ì
machines«á  Thσ UCP═ projec⌠ attempt≤ t∩ addres≤ thi≤ probleφ b∙á makinτ ì
informatioεá oεá ßá widσ rangσ oµ CP/═ computer≤á available«á  Thσá nex⌠ ì
articlσá wil∞ discus≤ somσ strategie≤ fo≥ gettinτá arounΣá compatibilit∙ ì
problems on CP/M and other computers.

.paè.he

.he UCPM Manual, Introductory Materials, Page #

            Strategies for Overcoming Compatibility Problems


A.  CP/M Compatibility Problems

     "He'≤á ßá COMPUTE╥á PROGRAMMER,ó m∙ grandmothe≥ saiΣ oµá ßá distan⌠ ì
cousin¼ he≥ eye≤ bulging«  Wha⌠ thi≤ mean⌠ t∩ he≥ wa≤ tha⌠ m∙ cousiε wa≤ ì
oε ß pa≥ witΦ braiε surgeon≤ anΣ Einsteins«á  Indeed¼á therσ wa≤ ßá timσ ì
wheε programmer≤ haΣ t∩ bσ intelligent«  Iε thosσ days¼ iµ onσ wisheΣ t∩ ì
writσá somethinτá t∩ ß screeε o≥ ß piecσ oµ magnetiπ tape¼á onσá haΣá t∩ ì
writσ bottom-leve∞ routine≤ fo≥ eacΦ process«á  Programminτ wa≤ a⌠ leas⌠ ì
aε arcanσ art¼ iµ no⌠ ß rigorou≤ science«

     Wha⌠á openeΣ programminτ u≡ t∩ Bear≤ oµ Ver∙ Littlσ Braiε likσ PooΦ ì
anΣ mσ wa≤ thσ developmen⌠ oµ OPERATIN╟ SYSTEM╙ whicΦ coulΣ handlσá low-ì
leve∞ inpu⌠ anΣ outpu⌠ operations«á  Thesσ alloweΣ thσ programme≥ t∩ usσ ì
ßá se⌠á oµ standarΣ "systeφ calls,ó whicΦ woulΣ worδ oε an∙ compute≥á oε ì
whicΦ thσ operatinτ systeφ haΣ beeε implemented«  CP/M¼ developeΣ b∙ Dr« ì
Gar∙á Kildal∞ wh∩ foundeΣ Digita∞ Research¼á Inc.¼á becamσ thσá standarΣ ì
operatinτ systeφ oε 8-bi⌠ microcomputer≤ iε thσ latσá 1970s«á  Operatinτ ì
system≤á likσ CP/═ wen⌠ ß lonτ wa∙ toward≤ solvinτ problem≤ oµá softwarσ ì
anΣ hardwarσ compatibilit∙ fo≥ programmers«á  Bu⌠ threσ o≥ fou≥ critica∞ ì
problem≤ remaineΣ iε thσ CP/═ world«

     (a⌐á  Iε thσ firs⌠ place¼á therσ wa≤ n∩ standarΣ vide∩á systeφá fo≥ ì
CP/═á computers«á  Earl∙á CP/═ machine≤ utilizeΣá commercially-availablσ ì
datß terminals¼ eacΦ oµ whicΦ haΣ it≤ owε se⌠ oµ escapσ code≤ t∩ contro∞ ì
thσ screen«  Wheε self-containeΣ CP/═ computer≤ werσ developeΣ (likσ thσ ì
Northstar¼ Osborne¼ anΣ Kaypr∩ computers)¼ the∙ utilizeΣ termina∞ escapσ ì
sequence≤ modeleΣ oε thosσ oµ earlie≥ datß terminals¼á bu⌠ addeΣá consiì
derablσ capbilitie≤ beyonΣ them¼á sucΦ a≤ memory-mappeΣ video¼ ß variet∙ ì
oµ vide∩ attributes¼ anΣ characte≥ o≥ pixe∞ graphics«  EacΦ CP/═ prograφ ì
haΣá t∩á bσ adapteΣ t∩ thσ specifiπ compute≥ iµ i⌠ wa≤ t∩ utilizσá thei≥ ì
more sophisticated features.

     (b⌐ Iε thσ seconΣ place¼á therσ developeΣ problem≤ witΦ disk-forma⌠ ì
compatibility«á  Therσ wa≤ ß generiπ CP/═ disδ format¼á bu⌠ i⌠ wa≤ aε 8ó ì
format¼ anΣ i⌠ employeΣ single-densit∙ recordinτ techniques«  Wheε 5.25ó ì
disδá drive≤ anΣ double-densit∙ (anΣ double-sided⌐ recordinτá technique≤ ì
becamσ available¼á CP/═ hardwarσ manufacturer≤ developeΣ ß vas⌠ arra∙ oµ ì
differen⌠ disδ formats¼ eacΦ incompatiblσ witΦ thσ other«

     (c⌐á Iεá thσ thirΣ place¼á therσ werσ developinτá genera∞á hardwarσ ì
incompatibilitie≤ betweeε thσ CP/═ computers«  Earlie≥ machine≤ useΣ thσ ì
Inte∞ 808░ c.p.u«á chip¼á bu⌠ late≥ one≤ tooδ advantagσ oµ thσá extendeΣ ì
instructioε set≤ oµ thσ 808╡ o≥ especiall∙ thσ Ziloτ Z8░ chip«  Softwarσ ì
usinτá Z8░á instruction≤á coulΣá operatσ oεá memor∙á anΣá perforφá othe≥ ì
function≤ mucΦ morσ quickly¼ bu⌠ coulΣ no⌠ bσ executeΣ oε thσ Inte∞ 808░ ì
chip«á  Variou≤ chip≤ haΣ differen⌠ clocδ speeds«á  Differen⌠ computers¼ ì
moreover¼á haΣ varyinτ inpu⌠ anΣ outpu⌠ capabilities«  Differen⌠ system≤ ì
for serial communication posed very serious problems for programmers.

     Part≤ 2¼á 3¼á anΣ ┤ oµ thσ UCP═ manua∞ givσ informatioε relevan⌠ t∩ ìèthesσá threσá areas¼á Par⌠ ▓ addressinτ genera∞á hardwarσá compatibilit∙ ì
problems¼á Par⌠á │ addressinτ termina∞ anΣ vide∩ compatibilit∙ problems¼ ì
and Part 4 addressing problems of disk format incompatibilities.

     (d⌐ Therσ i≤ onσ furthe≥ areß oµ compatibilit∙ problem≤ tha⌠ shoulΣ ì
bσá noted«á  Thσá CP/═ operatinτ systeφ itselµá passeΣá througΦá severa∞ ì
generation≤á oµ development¼á anΣ companie≤ anΣ privatσ programmer≤ havσ ì
madσ furthe≥ development≤ iε CP/═ compatiblσ software«  CP/═ versioε 2.▓ ì
becamσ ß dσ factoé standard¼á althougΦ CP/═ versioε 3.░ (als∩ calleΣ CP/═ ì
Plus⌐á madσ critica∞ improvement≤ anΣ wa≤ adopteΣ oε variou≤á computers«  ì
Digita∞ ResearcΦ als∩ releaseΣ MP/M¼ ß multitaskinτ versioε oµ CP/M«  Iε ì
thσ mid-1980≤ developmen⌠ oµ ne≈ Consolσ CommanΣ Processor≤ wen⌠ on¼ anΣ ì
sincσá theε entirσ replacement≤ fo≥ CP/═ (sucΦ a≤ Echelon'≤ ZRDOS⌐á havσ ì
beeε available«á  Par⌠ ▓ oµ thσ UCP═ manua∞ note≤ whicΦ version≤ oµ CP/═ ì
or equivalent systems are implemented on various hadware.


B.  Strategies for Overcoming CP/M System Incompatibilities

     1.  Strategy 1:  Revision of Source Code, Recompilation

     Giveεá thσ problem≤ outlineΣ above¼á ho≈ doe≤ onσ producσá program≤ ì
tha⌠á caε bσ implementeΣ oε ß rangσ oµ CP/═ computers┐á  Thσ mos⌠á basiπ ì
solutioεá woulΣ bσ t∩ revisσ thσ sourcσ codσ anΣ possibl∙ recompilσá thσ ì
prograφá fo≥á eacΦ implementation«á  Thi≤ ha≤ thσ advantagσ oµá enablinτ ì
eacΦá implementatioε t∩ takσ advantagσ oµ machine-specifiπá feature≤á t∩ ì
thσá maximum¼á bu⌠á i⌠á ha≤ thσ disadvantagσ oµ requirinτ thσá step≤á oµ ì
recompilatioεáá (anΣá possibl∙á reassembly⌐á fo≥á al∞á bu⌠áá interpreteΣ ì
languages«á  WitΦ interpreteΣ languages¼á thi≤ strateg∙ i≤ usuall∙á preì
ferred«á  I⌠á i≤á als∩ useΣ witΦ highl∙ machine-specifiπá program≤á (fo≥ ì
instance¼á thσá ZCP╥ serie≤ oµ Consolσ CommanΣ Processors)«á  Iεá eithe≥ ì
case¼á thi≤ strateg∙ require≤ carefu∞ modulizatioε oµ sourcσ code¼ ofteε ì
witΦá machine-specifiπ codσ locateΣ a⌠ thσ beginninτ s∩ a≤ t∩ makσ reviì
sioε anΣ recompilatioε morσ straightforward.


     2.  Strategy 2:  Inserts

     Thσ usσ oµ insert≤ i≤ structurall∙ equivalen⌠ t∩ thσ firs⌠ strateg∙ ì
above¼ bu⌠ ofteε involve≤ morσ carefu∞ specificatioε oµ thσ requirement≤ ì
fo≥á aε inser⌠ (anΣ oµ coursσ carefu∞ modulizatioε oµ thσ sourcσá code)«  ì
Oεá thi≤á strategy¼á thσá sourcσ codσ ha≤ ß poin⌠ a⌠á whicΦá ßá machine-ì
specifiπ blocδ oµ codσ i≤ t∩ bσ inserted¼ anΣ insert≤ arσ supplieΣ fo≥ ß ì
variet∙ oµ machines«á  Again¼ reassembl∙ anΣ recompilatioε arσ required«  ì
Somσá user-supporteΣ program≤ tha⌠ requirσ ß higΦ degreσ oµ systeφá speì
cifiπá codσá utilizσ inserts¼á mos⌠ notabl∙ thσ serie≤ oµá BY┼á program≤ ì
whicΦ allow CP/M computers to be used remotely.


     3.  Strategy 3:  Overlays

     Overlay≤á arσá perhap≤á thσ mos⌠á commoεá strateg∙á fo≥á overcominτ ì
incompatibilitie≤á fo≥ user-supporteΣ software«á  Aε overla∙ involve≤á ß ì
se⌠á oµ codσ tha⌠ ha≤ beeε converteΣ (typically⌐ int∩ Inte∞ HEXá format¼ ì
anΣá whicΦá ma∙á theεá bσ overlaiΣ oε aε existinτá prograφá a⌠á specifiπ ìèposition≤ specifieΣ iε thσ assembl∙ codσ anΣ theε iε thσ HE╪ file«  Thi≤ ì
approacΦá doe≤á no⌠ requirσ recompilation¼á onl∙ thσá actua∞á overlayinτ ì
accomplisheΣ typicall∙ b∙ thσ usσ oµ DDT¼á SID¼á o≥ MLOAD«á  ┴á possiblσ ì
disadvantagσá oµ thi≤ strateg∙ i≤ tha⌠ ne≈ user≤ ma∙ no⌠ understanΣá thσ ì
usσá oµ DDT¼á SID¼á o≥ MLOAD¼á anΣ thu≤ ma∙ finΣ installatioε fo≥á thei≥ ì
computer≤ frustrating«  Oε thσ othe≥ hand¼ mos⌠ folk≤ wh∩ havσ useΣ CP/═ ì
for very long have learned to do this.


     4.  Strategy 4:  Install Programs

     Thσá strateg∙á utilizeΣá iεá thσá mos⌠á sophisticateΣá commerciall∙ ì
produceΣá program≤ (sucΦ a≤ Wordstar¼á SuperCalc¼á anΣ dBasσ II⌐ anΣá iε ì
somσá user-supporteΣá softwarσá (sucΦ a≤ VDE⌐ i≤ t∩á suppl∙á ßá separatσ ì
prograφá whicΦá lead≤ thσ use≥ througΦ thσ step≤á oµá installation«á  Aε ì
instal∞á prograφ caε bσ ß ver∙ nicσ feature¼á bu⌠ somσ arσ a≤ comple° a≤ ì
installinτ aε overlay¼ anΣ thσ productioε oµ aε instal∞ prograφ require≤ ì
considerablσá worδá oεá thσ par⌠ oµá thσá programmer¼á anΣá considerablσ ì
information on the variety of computers.


     5«  Strateg∙ 5║  Autodetec⌠ Software

     Thi≤ shoulΣ bσ listeΣ a≤ ß logica∞ thougΦ no⌠ ß testeΣ possibility«  ì
I⌠ áwoulΣ bσ possiblσ t∩ writσ CP/═ softwarσ iε sucΦ ß wa∙ tha⌠ áinitia∞ ì
bit≤ áoµ codσ coulΣ detec⌠ whosσ BIO╙ i≤ presen⌠ (b∙ scanninτ thσ áfirs⌠ ì
fe≈ ábytes¼ ásay¼ oµ thσ BIO╙ ColΣ Star⌠ routinσ t∩ seσ áwhat'≤ áthere)«  ì
Thσ áprograφ ácoulΣ átheε utilizσ interna∞ sequence≤ áappropriatσ át∩ áß ì
variet∙ oµ terminals«  Thi≤ approach¼ howeve≥ woulΣ requirσ ß gooΣ ádea∞ ì
oµ worδ iε detectinτ differen⌠ BIO╙ signature≤ (ofteε morσ thaε onσ áfo≥ ì
eacΦ CP/═ computer)¼ anΣ migh⌠ resul⌠ iε codσ s∩ bulk∙ tha⌠ i⌠ woulΣ ábσ ì
impractica∞ oε existinτ CP/═-baseΣ computers.


C.  Strategies for Compatibility Problems between Operating Systems

     Man∙á programmer≤ wil∞ bσ unwillinτ t∩ devotσ ß grea⌠ dea∞ oµá CP/═ ì
programming¼á duσ t∩ thσ limitation≤ iε thσ marke⌠ indicateΣ above«á  I⌠ ì
woulΣá bσá attractive¼á theεá t∩á develo≡á codσá tha⌠á coulΣá bσá easil∙ ì
translated¼á no⌠ onl∙ t∩ othe≥ CP/═ systems¼á bu⌠ als∩ t∩ computer≤ witΦ ì
othe≥ operatinτ systems¼á sucΦ a≤ thσ IB═ P├ serie≤ anΣ compatibles¼ thσ ì
AtarΘ S╘ series¼á thσ Commodorσ Amigß series¼á anΣ UNIX-baseΣ computers«  ì
Iε thi≤ case¼ thσ strategie≤ indicateΣ abovσ wil∞ no⌠ suffice¼ sincσ thσ ì
wholl∙á incompatiblσ instructioε set≤ utilizeΣ oε othe≥ system≤á mandatσ ì
tha⌠ ß completσ revisioε o≥ recompilatioε oµ thσ codσ necessary«  Neverì
theless¼á therσ arσ a⌠ leas⌠ tw∩ strategie≤ fo≥ accomplishinτ thi≤ goal«


     1.  Strategy 1:  Code Translation

     I⌠ i≤ possible¼á utilizinτ specia∞ software¼ t∩ translatσ codσ froφ ì
onσ processo≥ int∩ equivalen⌠ codσ fo≥ anothe≥ processor«á  Onσ suspect≤ ì
tha⌠á thi≤á i≤á thσ techniquσ tha⌠ wa≤ useΣá wheεá CP/═á program≤á (likσ ì
Wordsta≥á anΣá dBasσá II⌐á werσ firs⌠ porteΣ ove≥ t∩ thσá IB═á PC'≤á anΣ ì
compatibles«  Nevertheless¼ thσ translatioε almos⌠ neve≥ take≤ advantagσ ìèoµá morσá sophisticateΣá operation≤ oε thσá targe⌠á processor¼á anΣá thσ ì
translatioεá usuall∙ require≤ considerablσ effor⌠ t∩ interfacσ witΦá thσ ì
operatinτá systeφá anΣá othe≥á input-outpu⌠á facilitie≤á oεá thσá targe⌠ ì
computer¼á sincσ method≤ fo≥ interfacinτ diffe≥ greatl∙ froφ onσá systeφ ì
t∩á another«á  (Thσ mos⌠ obviou≤ examplσ i≤ tha⌠ althougΦ MSDO╙ anΣá thσ ì
IB═á P├á Disδá Operatinτ Systeφ utilizσ somσ oµ thσ samσ BDO╙á call≤á a≤ ì
CP/M¼ thσ call≤ arσ madσ b∙ call≤ t∩ locatioε 0╡ unde≥ CP/═ anΣ arσ madσ ì
b∙ ß cal∞ t∩ interrup⌠ 21Φ unde≥ MSDOS)«


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     2.  Strategy 2:  Higher Level Languages

     Mos⌠ programmer≤ intendinτ t∩ develo≡ softwarσ fo≥ highl∙ differen⌠ ì
processor≤á anΣ operatinτ system≤ havσ turneΣ t∩ highle≥ leve∞ language≤ ì
whicΦá havσ ß higΦ degreσ oµ systeφ independence«á  Aε examplσ woulΣá bσ ì
thσ ├ programminτ language«  Therσ arσ a⌠ leas⌠ tw∩ problem≤ involveΣ iε ì
thi≤ approach«á  Iε thσ firs⌠ place¼á thσ usσ oµ sucΦ ß languagσá almos⌠ ì
alway≤ require≤ thσ threσ step≤ oµ compilation¼á assembly¼á anΣ linking«  ì
Second¼á highe≥á leve∞á language≤á havσ stil∞á (largely⌐á no⌠á developeΣ ì
specification≤á fo≥ usinτ morσ sophisticateΣ feature≤ sucΦ a≤á graphics¼ ì
alternatσá characte≥á sets¼á pointe≥ device≤ ("mice")¼á o≥á asynchronou≤ ì
communications«á  Thus¼á programmer≤ stil∞ tenΣ t∩ spenΣ ßá considerablσ ì
amoun⌠á oµá timσá a⌠á thσá system≤á leve∞á developinτá high-speed¼á morσ ì
sophisticateΣ systeφ interfaces«  Iε thi≤ regard¼ yo⌡ migh⌠ watcΦ fo≥ m∙ ì
ALTI╧á package¼áá whicΦá offer≤á convention≤á o≥á specification≤á fo≥á ├ ì
programming between different hardware configurations.

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