DOS code in CP/M? Revisited...

Guy Sotomayor Jr ggs at
Thu Jul 14 12:03:26 CDT 2016

> On Jul 14, 2016, at 9:46 AM, Fred Cisin <cisin at> wrote:
> When IBM decided to take over the personal computer market, they didn't do their homework very well.
> Intel convinced them to use the 8088, to have a gateway into 16 bit, instead of building a true 8 bit machine.
> One of the IBM people had seen a "Microsoft Softcard" (a Z80 co-processor plus CP/M for Apple][).

IBM chose the 8088 because the bus was close enough to the 8085 that the peripherals from the S/23 could
be re-used with minor tweaks (in many cases just a re-layout).

They wanted something that would allow > 64KB of RAM without having to go through the pains of what was
done on S/23 (it was an 8085 system that has 192KB of ROM and upto 128KB of RAM) and none of the 8-bit
micros could do that.

IBM had looked at the PC market for a while.  It was actually TJ Watson Jr that instructed that a “skunk” team
be formed to see how quickly a PC with an IBM logo could be produced.  He was afraid of Apple making
inroads into IBM’s traditional markets and wanted to prevent that.  It was never envisioned to be a huge market
for these things…it was viewed only as a hobbyist thing that had the potential to take away business from 
IBM’s traditional machines.

TTFN - Guy

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