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Most of the early CP/M systems I encountered were running on Zilog Z80 CPUs. There were other OSes as well but CP/M was very popular. I used dBase II on a Xerox

Most of the early CP/M systems I encountered were running on Zilog Z80 CPUs. There were other OSes as well but CP/M was very popular. I used dBase II on a Xerox 820 which was pretty nice with soft white monochrome text. CP/M was also very portable and eventually ended up on Atari ST 68000 machines which I also used with the GEM desktop/graphics environment. There was even a CP/M card for the Apple II that had a Z80 on it.

Twirrim 4y ago
GEM Desktop, now that's some nostalgia. First GUI I ever used, on an Amstrad PC-1512. Can barely remember it now other than a feeling of "wow", swiftly followed by "but none of my DOS games run on it, meh" :)
- UncleSlacky 4y ago
  It's still around (it was open-sourced a while ago) and OpenGEM is also available as part of FreeDOS: https://www.opendawn.com/opengem/ https://www.opendawn.com/opengem/
- karmakaze 4y ago
  Oh yeah before Atari ST I remember how GEM was typically only used on the PC to run Ventura Publisher which came with a bundled copy of GEM.
cmrdporcupine 4y ago
GEMDOS on the ST isn't really CP/M. It was a DR product, yes, and the API was somewhat based on CP/M, but it was also a new thing not ABI compatible with CP/M and also pulled in a lot from MS-DOS. It was built specifically to run GEM on systems where MS-DOS was not present (because GEM was written for MS-DOS originally). So the 68k, and was prototyped on the Apple Lisa and some Motorola VME machines before porting to the Atari ST. The source code for both CP/M 68k and GEMDOS are available these days and one can see that while some small bits are borrowed between them (the program loader, for example), on the whole it's a whole new source tree. I believe parts of the GEMDOS sources did become the basis of what eventually became DR-DOS on the x86.
- karmakaze 4y ago
  Oh yes, you're right! I'd forgotten some of how things got finalized. I started using the Atari 520ST with pre-release CP/M-68K docs and software before settling on GEMDOS/TOS. It was all in a bad state with a literal stack of paper given to me (rather than electronic docs) that only roughly corresponded to the state of the software so must have been in flux. Even the GEM parts were still being worked out. I recall using just the "Line-A"[0] graphics calls which were I believe 000a traps that were ROM calls to routines before getting access to higher level GEM graphics support. There's mention of CP/M-68K and TOS with info on the Atari 130ST/260ST[1] (which also happened to have 512KB). I do recall later getting the OS in ROM of later hardware so boots were quicker. [0] http://toshyp.atari.org/en/006001.html http://toshyp.atari.org/en/006001.html [1] https://www.old-computers.com/museum/computer.asp?c=922 https://www.old-computers.com/museum/computer.asp?c=922

Twirrim 4y ago

GEM Desktop, now that's some nostalgia. First GUI I ever used, on an Amstrad PC-1512. Can barely remember it now other than a feeling of "wow", swiftly followed by "but none of my DOS games run on it, meh" :)

UncleSlacky 4y ago
It's still around (it was open-sourced a while ago) and OpenGEM is also available as part of FreeDOS: https://www.opendawn.com/opengem/ https://www.opendawn.com/opengem/
karmakaze 4y ago
Oh yeah before Atari ST I remember how GEM was typically only used on the PC to run Ventura Publisher which came with a bundled copy of GEM.

cmrdporcupine 4y ago

GEMDOS on the ST isn't really CP/M. It was a DR product, yes, and the API was somewhat based on CP/M, but it was also a new thing not ABI compatible with CP/M and also pulled in a lot from MS-DOS. It was built specifically to run GEM on systems where MS-DOS was not present (because GEM was written for MS-DOS originally). So the 68k, and was prototyped on the Apple Lisa and some Motorola VME machines before porting to the Atari ST. The source code for both CP/M 68k and GEMDOS are available these days and one can see that while some small bits are borrowed between them (the program loader, for example), on the whole it's a whole new source tree. I believe parts of the GEMDOS sources did become the basis of what eventually became DR-DOS on the x86.

karmakaze 4y ago
Oh yes, you're right! I'd forgotten some of how things got finalized. I started using the Atari 520ST with pre-release CP/M-68K docs and software before settling on GEMDOS/TOS. It was all in a bad state with a literal stack of paper given to me (rather than electronic docs) that only roughly corresponded to the state of the software so must have been in flux. Even the GEM parts were still being worked out. I recall using just the "Line-A"[0] graphics calls which were I believe 000a traps that were ROM calls to routines before getting access to higher level GEM graphics support. There's mention of CP/M-68K and TOS with info on the Atari 130ST/260ST[1] (which also happened to have 512KB). I do recall later getting the OS in ROM of later hardware so boots were quicker. [0] http://toshyp.atari.org/en/006001.html http://toshyp.atari.org/en/006001.html [1] https://www.old-computers.com/museum/computer.asp?c=922 https://www.old-computers.com/museum/computer.asp?c=922