Available: IBM desktop "System/23 Datamaster"

On Aug 7, 2014, at 10:49 PM, Mark J. Blair <nf6x at nf6x.net> wrote: BASIC and the internal OS (such as it is) are in ROM. To do other utility like things (copy diskettes, format them, etc) you need the "CSF" diskette(s). CSF = Customer Support Facility as I recall. System/23 was the precursor to the PC at IBM. This is true for several reasons: 1. It was the first "computer" at IBM that didn't use an IBM microprocessor. It's what allowed management to go forward with an "open" PC design that contained a majority of non-IBM designed components. 2. The PC being on a short schedule and tight budget re-used a lot from the System/23. The I/O bus is actually the System/23 I/O bus rotated 180 degrees (so that you couldn't use the cheaper PC cards in the System/23). I never did much with the CSF stuff because I was working on the ROM code. I wrote about ~20% of the code in the ROM. Mainly it was the input/output data formatting, "floating" point code (which is actually all done in 17 digit BCD with exponents) and reconstituting the source when you did a LIST. It was all written in 8085 assembler. TTFN - Guy