On 8/4/19 6:16 PM, Herb Johnson via vcf-midatlantic wrote:
On Sat, Aug 03, 2019 at 11:13:28PM -0400, Evan Koblentz via vcf-midatlantic wrote:
Does the museum have or need this?
We have a couple of 820s, but we don't have this. Do we need it? I don't know... anyone have thoughts about that?
If you have other good examples of the dual processor PC with CP/M showing the attempt to bridge the generations another may not be that significant. The page says it may had a little better implementation than some with the concurrent processing.
There were a number of microcomputers in the early 1980's, which incorporated both an 8085 and an 8088, or a Z80 and an 8088. The Heath/Zenith Z-100 (Z-121) switched between an 8085 or an 8088. The Compupro 8/16 used an 8085/8088 S-100 CPU card, similar circuits. I believe NorthStar had an 8088 board option for their Z80 based Advantage (non-S-100 computer). There are other examples. Likewise, some MS-DOS computers ran an ISA bus Z80 card (Baby Blue, etc.).
Why do this? Because of the rise of MS-DOS during the age of CP/M-80. Keep in mind that through the late 1970s and into the 1980's, CP/M-80 was the leading Intel-compatible operating system. These 8088 options were ways to provide some kind of compatibility and future-support, for MS-DOS products and for "Big Blue" IBM. The Z80 cards for IBM PC's, was a way to run legacy software - until PCs were fast enough to emulate CP/M-80.
Interesting time, I have an ATR8000 for the Atari 8 bit computer. The ATR8000 could run as a drive interface (8", 5 1/4 and 3 1/2) or CP/M machine or with a coprocessor board a 8088 and run DOS. A very odd time as no one knew what was going on with CP/M vs MSDOS. -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies