Bit Cor­po­ra­ti­on Bit90

Lese­dau­er 10 Minu­ten

The (too) late competitor

The Bit Cor­po­ra­ti­on Bit90 has the dis­fa­vour of late birth. When it was laun­ched in 1984 by the Tai­wa­ne­se com­pa­ny Bit Cor­po­ra­ti­on, the C64 alrea­dy show­ed what a suc­cess­ful com­pu­ter should look like.

The ingre­dients for a mil­li­on-sel­ler in the Orwel­li­an year were cer­tain­ly no memo­ry of puny 18 KB and a (albeit superb!) rub­ber key­board. In addi­ti­on, the­re was the steep pri­ce of about 600 DM with 34 KB RAM (or 500 DM with 18 KB RAM).

The Com­mo­do­re 64 was not much more expen­si­ve at that time with 698 DM, but much bet­ter – in pret­ty much every respect. Con­ver­ted to today’s (2021) pri­ces, you have to com­pa­re the Bit 90 with a good PC:

18 KB ver­si­on: 750 Euro

34 K ver­si­on: 895 Euro

Com­mo­do­re 64: 1.400 Euro!

You could also cal­cu­la­te this with other devices: Click here for my purcha­sing power calculator.

My device

I got my device by chan­ce in 1989. I dro­ve my bro­ther to a buddy’s com­pa­ny. The­re, on one of tho­se then-com­mon “desi­gner” steel shel­ves, were a Sin­c­lair QL (with manu­al and a bag full of micro­dri­ves!) and the Bit90 with expan­si­on cards.

Both devices were fami­li­ar to me and even then I had the urge to collect devices I lik­ed, even if I could­n’t actual­ly use them. What had I paid? I’m not sure any more, but I think it was 20 DM. No kidding.

Well, both of them were alrea­dy com­ple­te­ly unfa­shion­ab­le at that time and my brother’s bud­dy did­n’t care about the money, he just wan­ted to get rid of the stuff. I think they knew each other from some kind of loo­se Schnei­der CPC 464 “club”.


Now I’ll go a bit fur­ther: For me, the Bit90 is the Mac­Book Air among home computers.

What the Bit90 also has in com­mon with the Mac­Book Air is that it would pro­bab­ly fit in one of tho­se office mai­ling bags. Or not. 🙂

Only the Enter­pri­se 64/​128 might be a bit flat­ter, but it does­n’t reach this ele­gant self-evi­dence by far.

As chic as the device is, it does­n’t feel very valu­able. Espe­cial­ly the low weight is disap­poin­ting. Unfor­tu­n­a­te­ly, the sil­ver edges quick­ly wear off, so the device loses its beau­ty over time.

Bit Corporation Bit90
Bit Cor­po­ra­ti­on Bit90

Dimen­si­ons: 330 x 214 x 50 mm (WxDxH) 66 keys, sepa­ra­te cur­sor block

Bit Corporation Bit90 Logo
Bit Cor­po­ra­ti­on Bit90 chro­me logo
Bit Corporation Bit90 Typenschild
Bit Cor­po­ra­ti­on Bit90 nameplate

Made in Tai­wan – yes, but how many were pro­du­ced? Is my device real­ly only the 913th? Or were the­re more than 300,913 in total after all? I think the­re must have been half a mil­li­on devices in the end. That’s not very much.


It’s a pity that the device was­n’t a big­ger suc­cess becau­se the Bit90 offe­red an inte­res­ting addi­tio­nal func­tion: A com­ple­te com­pa­ti­bi­li­ty to the well-known video game Cole­co Vision!

Of cour­se, this limi­ted the reso­lu­ti­on and colour depth to 256×192 pixels with 16 colours, but this still put it in the lower mid­field of the com­pe­ti­tors in 1984. The CPU line was also ok, a Z80A clo­cked with 3.58 MHz acted as the heart of the Bit90, which also allo­wed the exe­cu­ti­on of CP/​M programs.

Well, the Com­mo­do­re 64 was not the inten­ded oppo­nent of the Bit90 becau­se the Bit Cor­po­ra­ti­on was actual­ly at home in the con­so­le busi­ness. This com­pa­ny pro­du­ced games for the Ata­ri VCS and the NES from Nin­ten­do. One of the games also known in this coun­try was “Bob­by geht heim”, which was dis­tri­bu­t­ed by “Quel­le”.

Bit Corporation Bit90 Erweiterungsport
Bit Cor­po­ra­ti­on Bit90 expan­si­on port

Oh! A design flaw abo­ve the Cole­co slot (wire bridge). But well, if you look at the first Ata­ri ST, which had felt dozens of the­se wire brid­ges, you can safe­ly turn a blind eye here. This brings us to the inner workings.

Inner life

The Bit90 was actual­ly an upgraded game con­so­le – just like its pre­de­ces­sor, the Bit60. This one was “only” com­pa­ti­ble to the Ata­ri VCS 2600, but also the Bit90 can be made VCS com­pa­ti­ble by an adapter.

For me per­so­nal­ly, this adap­ter and a Bit60 repre­sent the holy grail. This is hard­ware that abso­lute­ly appeals to me.

A Bit60 is a more than inte­res­ting device. If you think of the grot­ty com­pu­ter expan­si­on for the Ata­ri VCS, which was also dis­tri­bu­t­ed by “Quel­le”, the expec­ta­ti­ons go abso­lute­ly down the drain.

But when I look at the suc­cess­ful and qui­te power­ful Bit90, I can hard­ly belie­ve that the Bit60 should have been an abso­lu­te zero num­ber. Only… the VCS was not a device for which the deve­lo­pers lik­ed to wri­te soft­ware – qui­te the oppo­si­te, as one hears.

Well, the Bit90 is actual­ly a game con­so­le, yes, and is the­re not­hing else?

Yes, the­re is, first of all the gran­dio­se design: Dark green keys, black edging and housed in a flat, sil­ver case. And the name­pla­tes in chro­me. That’s real­ly some­thing! And I have to say to all rub­ber key­board haters: I haven’t had bet­ter keys of this kind under my fin­gers yet.

Bit Corporation Bit90 Tastatur
Bit Cor­po­ra­ti­on Bit90 keyboard
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The inner values were qui­te remar­kab­le, they cor­re­spon­ded to the Cole­co Visi­on, which pro­bab­ly offe­red the best arca­de games imple­men­ta­ti­ons at that time: Zilog Z80A (Z8400A) CPU with 3.58 MHz 24 KB ROM 18/​34 KB RAM

TMS9929 gra­phics unit (known from the TI 99/​4a and the MSX cal­cu­la­tors) AY‑3–8910 sound gene­ra­tor (among others also in: arca­de machi­nes, CPC seri­es, Spec­trum, ST).

The “croo­ked” RAM is becau­se the device counts the video play­er (TMM2016AP) of 2 KB RAM. The gra­phics chip could use up to 16 KB of dedi­ca­ted video RAM. Howe­ver, only the men­tio­ned 2 KB of RAM instal­led for this in the Bit90.

Gra­phics: 256 x 192 (64 x 48 LoRes) pixels (32 x 24 cha­rac­ters, ), 16 colours, 32 spri­tes (mono­chro­me). 34 lay­ers (pla­nes); cha­rac­ters, back­ground, and frame could take 16 colours each.

Sound: three voices, fre­quen­cy adjus­ta­ble in 1024 steps. Volu­me adjus­ta­ble in 16 steps. One enve­lo­pe gene­ra­tor, de-/ac­ti­vat­able for sin­gle voices. Random/​noise gene­ra­tor. The sound chip is gene­ral­ly capa­ble of out­put­ting a ste­reo signal, sin­ce the Cole­co­Vi­si­on did­n’t offer ste­reo sound eit­her, it’s mis­sing here too.

The device has a real reset but­ton and a wob­b­ly power but­ton (again, this was not always a given with the com­pe­ti­ti­on). Some tes­ters repor­ted that the device got too hot after a few hours and cras­hed.

Bit Corporation Bit90 Mainboard
Bit Cor­po­ra­ti­on Bit90 motherboard

The Tai­wa­ne­se know their tra­de: the clean con­struc­tion of the Bit90 inspi­res. You can guess why even today most note­books manu­fac­tu­red in Taiwan.


The real­ly exten­si­ve BASIC hard­ly left anything to be desi­red. Even if you could call up all com­man­ds via short­cuts on the key­board, as usu­al with e.g. Sin­c­lair, this was only a bonus and not a duty, sin­ce the com­man­ds could also be typed in as usual.

This is all gre­at. But unfor­tu­n­a­te­ly, the­re is only one line edi­tor and the BASIC is real­ly not the fas­test. The­re are no gra­phic com­man­ds like Line or Cir­cle, but sin­ce you can address every sin­gle pixel with the plot com­mand, you have to make your own short gra­phic routines.

Who the manu­fac­tu­rer of the BASIC is, remains in the dark, but as usu­al at that time it might be Micro­soft. The CPU sug­gests a MBASIC, but the com­man­ds all cor­re­spond pret­ty much to the TI 99/​4a, with which the Bit90 also shares the gra­phics unit.

Com­man­ds: auto, abs, asc, atn, bye eof, call, chr$, clear, clo­se, cont, copy, cos, data, def, dele­te, dim, edit, else, end, exp, fn, for, fre, gosub, hex$, home, if, in, inkey$, input, inscr, int, joyst, left$, len, let, list, ln, load, log, mid$, music, next, new, on, onerr-goto, open, opti­on-base, out, peek, plot, play, poke, pos, print, read, ran­do­mi­ze, rec, rem, renum, res­to­re, resu­me, return, right$, rnd, run, save, sgn, sin, spc, sqr, step, stop, str$, tab, tan, then, tem­po­tra­ce, to, untrace, val, wait This list makes the C64 fanboy’s jaw drop while his pants open. Isso!


Here, too, you can’t real­ly com­p­lain! At first glance, the con­nec­tions seem to be com­ple­te. In fact, howe­ver, one signi­fi­cant con­nec­tion is mis­sing: the one for a disk dri­ve! Rumour has it that the­re is actual­ly an expan­si­on card that would retro­fit this (with which connector?).

The prin­ter port, which is also mis­sing, is qui­te com­mon, or was inclu­ded in the pri­ce of 600 DM.

Coloeco-Visi­on com­pa­ti­ble modu­le slot 2x 9‑pin stan­dard joy­stick sockets

Expan­si­on port (pro­prie­ta­ry, board version)

Cas­set­te recor­der (DIN socket, 2400 baud)

Audio out­put (DIN socket) RGB cha­rac­ter con­nec­tor (DIN socket)

The Bit90 came with a moni­tor, a cas­set­te recor­der, a TV coax cable, an exter­nal power sup­ply (not Cole­co­Vi­si­on com­pa­ti­ble!) and a qui­te usable manu­al. A home com­pu­ter of that era comes with an RGB(!) moni­tor output?

Is CP/​M com­pa­ti­ble? Wow! And has a rub­ber key­board on the other side? Okaaaay…? :-O Just for clas­si­fi­ca­ti­on, CP/​M com­pa­ti­bi­li­ty was some­thing like DOS com­pa­ti­bi­li­ty at that time becau­se it enab­led the use of thousands of pro­fes­sio­nal programs.

An adult buy­er sim­ply expects a more usable key­board and more than the 32 x 24 cha­rac­ters per screen that the poor Bit90 could only offer. But let’s be honest: What did 95% of the C64 owners use the 1541 disk dri­ve for? To load games with it! Well, most games for the Bit90 were avail­ab­le on modu­le. Cole­co Visi­on modules!


The­re were also several expan­si­ons for the device. Among them of cour­se also urgent­ly nee­ded memo­ry expan­si­ons. All modu­les could be plug­ged into each other(!), so you could use several expan­si­ons at the same time. A gre­at thing that C64 owners could only dream of at that time.

Bit Corporation Bit90 Printer Interface Card
Bit Cor­po­ra­ti­on Bit90 Prin­ter Inter­face Card
Bit Corporation Bit90 Memory Card
Bit Cor­po­ra­ti­on Bit90 Memo­ry Card, here equip­ped with 16 K
Bit Corporation Bit90 Expansion Port
Bit Cor­po­ra­ti­on Bit90 Expan­si­on Port
Bit Corporation Bit90 Erweiterungskarten
Bit Cor­po­ra­ti­on Bit90 Expan­si­on Cards

Avail­ab­le should(!) be the fol­lowing extensions:

  • 16 KB RAM – up to maxi­mum 32/​48 KB RAM total sys­tem memory
  • 32 KB RAM – up to max. 48/​64 KB RAM total sys­tem memory
  • Cen­tro­nics
  • Flop­py­drive
  • Assem­bler modu­le (for the modu­le slot?)
  • Light pen expansion
  • VCS expan­si­on
  • RS323C
  • Modem
  • User­port

How many cards could be plug­ged in one after the other? Well, at least four or five essen­ti­al modu­les ((2x)RAM, flop­py, prin­ter, modem) should run tog­e­ther, if the power sup­ply is suf­fi­ci­ent and the modu­les don’t get into each other’s way.

But an IBM PC at that time usual­ly had only one 8‑bit ISA bus, which also had to share the band­width. The inte­res­ting thing about the expan­si­on cards is that they were not hob­by­ist solu­ti­ons without a case, as is often the case with C64, and that they can be plug­ged in one after the other. Fur­ther­mo­re, here hats off and bow to the Bit Cor­po­ra­ti­on, which deve­lo­ped a real­ly thought-out total system.


Tar­get groups: 

Well, what were the folks at Bit Cor­po­ra­ti­on thin­king with this device (and the Bit60 befo­re it)? They hoped that they could attract as cus­to­mers the peop­le who alrea­dy owned a Cole­co Visi­on (or with the VCS expan­si­on: an Ata­ri 2600) and who now wan­ted to switch to a home com­pu­ter after the video game crash the year befo­re. Wow! That was mil­li­ons of poten­ti­al cus­to­mers! Then the­re was the CP/​M com­pa­ti­bi­li­ty, which pro­mi­sed pro­fes­sio­nal use! What a mar­ket, what opportunities!


But unfor­tu­n­a­te­ly, it did­n’t work, or only to a limi­ted extent becau­se on the Com­mo­do­re 64 the pira­te sce­ne was alrea­dy raging in 1984 with dis­tri­bu­ti­on cen­tres in all nati­on­wi­de school yards. What is coo­ler than an old modu­le that you have on the shelf?

Right! A pira­ted cas­set­te or disk full of the latest games!

Well, in 1984 the che­a­pest flop­py disks still cost about five DM, but most­ly 7.50 DM upwards, which was cos­t­ly with pocket money of let’s say 20 or 25 Euro per mon­th. But on such a disk you could fit four or five games, some­ti­mes even more.


At that time, the Com­mo­do­re 64 had the (unten­ab­le) repu­ta­ti­on of being use­ful for school with the grand­par­ents, the finan­ciers, so child­ren and par­ents most­ly wan­ted a C64 and that alrea­dy deci­ded the race.

Rea­sons for failure:

Cole­co com­pa­ti­ble, CP/​M com­pa­ti­ble – so the soft­ware offer for this com­pu­ter can only be cal­led excel­lent, without dis­cus­sion! With exten­si­on, one could also still Why did the device fail then?

It was like many other good pro­ducts, which could not com­pe­te with worse pro­ducts on the mar­ket: Ford Edsel, Beta­max, Video 2000, Moto­ro­la ROKR, DAT, Mini­Disk – the list could be con­ti­nued for a long time, but the worst pro­duct, which inex­pli­ca­b­ly spread too far, was pro­bab­ly „Win­dows”.

Actual­ly, this is alrea­dy enough as a rea­son, becau­se peop­le are rather stu­pid in the mass, than that they would form a swarm intelligence.


A few years later, Com­mo­do­re fol­lo­wed the same line of thought with the C65, thin­king it would be a neat idea to launch a bee­fed-up 8‑bitter (the fas­test of its time) that cus­to­mers could just swap out for the ol’ C64 and keep all the peripherals.

In the end, the­re was less C65 than Bit90. That’s how it can go. But we should also brief­ly take a moment of remem­bran­ce for the Enter­pri­se 64/​128, also a gre­at device that found far too few customers. 😉

Cur­rent situation: 

Well, all in all, the Bit Cor­po­ra­ti­on Bit90 is actual­ly a dream device, which unfor­tu­n­a­te­ly fai­led to be suc­cess­ful. But today it is a real­ly nice collector’s item, which appeals to con­so­le and home com­pu­ter enthu­si­asts ali­ke, which is also reflec­ted by the pri­ce deve­lo­p­ment lately.

Anno­ta­ti­on: This arti­cle has been writ­ten as the first “fil­ler” arti­cle for the Home­Con web­site, which went live for the first time the next day. I foun­ded Home­Con tog­e­ther with Hol­ger Groh. A few weeks later, the first Home­Con took place in my for­mer place of resi­dence, Seli­gen­stadt, with an over­whel­ming success.

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