Ibm s-100 system?

william degnan billdegnan at
Sat Apr 23 18:01:53 CDT 2016

On Sat, Apr 23, 2016 at 5:56 PM, Jim Brain <brain at> wrote:

> On 4/22/2016 11:02 AM, Guy Sotomayor wrote:
>> I wrote a somewhat long post a while ago on why we’re still stuck with
>> various timing artifacts due to the original PC’s choice to use an NTSC
>> color burst crystal as the main crystal for the PC. TTFN - Guy
> Link?
> --
> Jim Brain
> brain at

I know Jon (Glitch works) has an S-100 card with this IBM square RAM.    I
saw it at VCF East the other weekend.

Anyway, I seem to recall that an S-100 system was used to actually test and
port the original IBM DOS 1.0 for 5 1/4" for the new IBM system.

I have a copy of a MS or IBM DOS for my CompuPro on 8" disk, I think it's
v. 1.25.  I also have a copy of 1.25 on my CBM 256x, with 8086
co-processor.   Neither of these were BEFORE the original IBM PC, but hint
at a time when there was a "DOS" in development floating around before the
actual IBM system.  This DOS could have been demoed in Europe on an S-100.

lots of conjecture here.  Just speculating.

@ BillDeg:
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