[HN Gopher] A Short History of CP/M-86
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A Short History of CP/M-86
Author : rbanffy
Score : 42 points
Date : 2024-06-10 10:36 UTC (1 days ago)
(HTM) web link (www.abortretry.fail)
(TXT) w3m dump (www.abortretry.fail)
| chasil wrote:
| One interesting thing about CP/M is that it didn't have
| subdirectories.
|
| "CP/M 2.2 had no subdirectories in the file structure, but
| provided 16 numbered user areas to organize files on a disk. To
| change user one had to simply type "User X" at the command
| prompt, X being the user number."
|
| https://en.wikipedia.org/wiki/CP/M
| pavlov wrote:
| MS-DOS (and PC-DOS) also didn't have subdirectories until
| version 2.0.
|
| These were floppy disk oriented operating systems, and at 360
| kB per floppy, directories were not really that useful.
|
| Hard disk support made it more urgent to offer Unix-style
| directories. Since the forward slash was already used for CLI
| parameters in the CP/M style, it couldn't be used as the path
| separator. So Microsoft chose the backslash instead, and it
| persists in Windows today.
| ghaff wrote:
| And arguably more file loaders than operating systems as
| such. I long thought it a sort of interesting question how
| things could have turned out differently if one of the many
| 16-bit operating systems (or Unix of course) kicking around
| in the minicomputer world had been more widely used on early
| PCs.
| dfawcus wrote:
| Some of the products mention on that piece were true
| operating systems.
|
| MP/M and its derivatives (MP/M-86, CCPM, CDOS) were all
| multitasking, multi-threading, multi-user, multi-
| terminal/console real time preemptive OSs. The bank
| switching versions also had a form of memory protection.
|
| CDOS-68k, CDOS-286 and the subsequent renamed to FlexOS
| products also had those capabilities, but with inherent
| memory protection.
|
| So it is only really the basic CP/M-86 product (lacking the
| MP/M bits) which was the simple program loader.
|
| In many ways the FlexOS product are sort of inspired from
| the DEC minicomputer RSX-11m OS; and the MP/M derivatives
| look like they were inspired by DEC RSX-11d (and hence
| RSX-15).
| ghaff wrote:
| Fair enough. I suppose that hardware resource constraints
| were sufficiently tight at the time that the "mass
| market" wouldn't have thanked you for something that
| might have cost twice as much (at a time when micros were
| already _quite_ expensive relative to today).
| nickdothutton wrote:
| I was an MP/M 2 user (Altos) for a while. It was a great
| system for a small workgroup, supporting a handful of
| (Volker Craig) Terminals. VT-52 clones IIRC.
| forinti wrote:
| In the Acorn DFS the "directory" was an attribute for each file
| that was just a letter prefixed to the file's name.
|
| It was used to group files. Since the original format only
| allowed 31 files per side, it wasn't really that useful. I
| never used it.
| cmrdporcupine wrote:
| _In 1982, Digital Research released CP /M-68K for the Motorola
| 68000. This was initially written in Pascal following DRI's
| acquisition of the MicroSYSTEMS company in Solana Beach. This
| port was originally made for the Atari ST, but Atari chose to go
| a different way_
|
| Odd, I hadn't heard the Pascal bit before. And the C/assembly
| source for CP/M 68k is out there to see (e.g.
| https://github.com/dwildie/cpm-68k)
|
| Further, while Atari did go a different direction, it wasn't
| _that_ different. DR 's "GEMDOS" is like a fusion of MS-DOS and
| CP/M 68k, designed to play the same role on the 68k that PC/MS-
| DOS did for GEM on the 8086. There's I think bits in there that
| came from the CP/M architecture and codebase (program loader, for
| one). GEMDOS not only ran on the ST but was built first on the
| Apple Lisa (and some Motorola VME machines too, I believe.)
|
| Past discussion: https://news.ycombinator.com/item?id=39368972
| 95014_refugee wrote:
| ... and the open-source clone (EmuTOS) has been widely ported
| since.
| chasil wrote:
| My major experience with GEM was Xerox Ventura Publisher.
|
| Ventura and Aldus Pagemaker were the two desktop publishing
| contenders on the PC. Pagemaker used Windows. Ventura ended up
| going to Windows as well (no surprise there).
|
| https://en.wikipedia.org/wiki/Corel_Ventura
| kabdib wrote:
| The Atari involvement wasn't until August 1984 or after. We
| never saw any Pascal source code for CP/M-68K (it had been
| ported to C by then, I suppose).
|
| CP/M-68K was awful, GemDos was a little better (written largely
| by Jason Loveman at DRI), but it had its own issues. The new
| program loader was one of the improvements we wanted.
| cmrdporcupine wrote:
| Thanks for chiming in. Always appreciate your recollections.
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