5 ms·

I'm pretty sure CP/M 86 was already a thing. I believe there was even Concurrent CP/M 86, which let you run up to 4 (or more?) virtual sessions concurrently. Li

by iqp 2mo ago

I'm pretty sure CP/M 86 was already a thing. I believe there was even Concurrent CP/M 86, which let you run up to 4 (or more?) virtual sessions concurrently. Light years ahead of MS-DOS but nobody wanted it, so DRI dumbed it down and added MS-DOS compatibility and re-released as DR-DOS (still superior to MS-DOS though).

dboreham 2mo ago
Not 386 though.
codebje 2mo ago
CP/M-86 was definitely a thing, but CP/M-386 was not. By the time the 386 existed, DRI had dropped the CP/M name in favour of Concurrent DOS - though they had MS-DOS compatibility in Concurrent CP/M - and, as you say, eventually renamed it to DR-DOS. Much as I loved DR-DOS, it did have occasional compatibility hiccups.
- m132 2mo ago
  Chances are those hiccups weren't without a reason! https://en.wikipedia.org/wiki/Jim_Allchin#Controversies https://en.wikipedia.org/wiki/Jim_Allchin#Controversies
  - codebje 2mo ago
    Also, it was super common practice to just go direct to undocumented internals. You didn't have a clean API to duplicate, you had all the untamed glory of a CPU with no MMU to deal with, and all the programs that did shonky things because they worked.
- lproven 2mo ago
  > Much as I loved DR-DOS, it did have occasional compatibility hiccups. Because MS carefully built them. This was proved in court. The developers who built the incompatibilities signed their work with their initials: AARD. https://en.wikipedia.org/wiki/AARD_code https://en.wikipedia.org/wiki/AARD_code How it was found: https://www.geoffchappell.com/notes/windows/archive/aard/index.htm https://www.geoffchappell.com/notes/windows/archive/aard/ind...
deleted 2mo ago
[deleted]
Brian_K_White 2mo ago
cp/m-86 targets 8086, which is no more useful or relevant to 386 protected mode than the original z80 version. Did you think they just picked the 68k version at random?
- skissane 2mo ago
  > cp/m-86 targets 8086, which is no more useful or relevant to 386 protected mode than the original z80 version. Did you think they just picked the 68k version at random? The big reason for picking the 68K version is it was mainly written in C (initially in Pascal, but they later switched to C.) By contrast, the more famous 8080 versions were largely written in assembly, as was the 8086 version. Well, CP/M-80 1.x was mostly written in PL/M, a dialect of PL/I developed by Gary Kildall, but CP/M-80 2.x+ was rewritten in assembly for speed; PL/M was still used for some of the utilities. Obviously, C compilers are much easier to come by nowadays than PL/M compilers are.
p_l 2mo ago
MS-DOS truly beat CP/M-86 when it extended the APIs and features in PC/MS-DOS 2.0 (heavily inspired by Xenix), like hierarchical file system. From then on, applications would target MS-DOS in addition to the curse of being too IBM PC specific
- pjmlp 1mo ago
  For a while Microsoft was betting their future with Xenix, what an alternative reality that could have been.
  - p_l 1mo ago
    I somewhat suspect that if not for multiple materials (not from MS) promoting deep dependency on IBM PC specifics, it might have worked out.
lproven 2mo ago
I don't want to just quibble for the fun of it but so much more of this is wrong than right that it's downright misleading. > I'm pretty sure CP/M 86 was already a thing. Yes it was. Launched after the IBM PC, though, which is why SCP wrote QDOS which they licensed to MS and became MS-DOS. How and why it was late: https://nemanjatrifunovic.substack.com/p/the-late-arrival-of-16-bit-cpm https://nemanjatrifunovic.substack.com/p/the-late-arrival-of... > I believe there was even Concurrent CP/M 86 There was. And then CCPM-286 and CCPM-386. > which let you run up to 4 (or more?) virtual sessions concurrently On the console -- but the selling point was that you could also attach dumb terminals to the serial ports and they could run DOS apps too. So you had a cheap multiuser box, where adding 3 or 4 or 8 more users cost about 10% as much as a network with 3 or 4 or 8 more client PCs. > Light years ahead of MS-DOS but nobody wanted it, No, not at all. One descendant is still supported today, some 45 years later. https://tgcs04.toshibacommerce.com/cs/groups/internet/documents/document/dg9z/njyw/~edisp/prod.tos660737.pdf https://tgcs04.toshibacommerce.com/cs/groups/internet/docume... > so DRI dumbed it down and added MS-DOS compatibility No, not even slightly. > and re-released as DR-DOS (still superior to MS-DOS though). Not a fair description at all. Here's how it went: MS-DOS beat it to market. So, DR brought multitasking and multiuser from MP/M to turn CP/M-86 into Concurrent CP/M: CCP/M-86 MS-DOS did great. So, lots of apps. So, DR added DOS compatibility to CCP/M. It also did a single-user OS, called DR DOS Plus. Oversimplification: this was a single-user non-multitasking CP/M-86 that read/wrote FAT and could run DOS apps. Intel did a new chip, the 80286. DR ported to it. A native protect-mode 286 OS, which used new 286 features to pre-emptively multitask DOS apps. Intel removed those features before it launched the 286. This killed DR's new OS. So, it refocused: it temporarily dropped DOS compatibility, and sold it as an RTOS instead, with a multitasking version of GEM as its GUI. Intel put the features back and Concurrent DOS 286 became a product but it was too late. This was a better OS/2 before OS/2 1.0 launched. Intel put DOS multitasking into hardware in the 386. DR rewrote CDOS286 in C creating CDOS386. This had really good DOS compatibility. So DR updated DOS Plus to make DR-DOS: a superset of MS-DOS 3.3, with FAT16 for big hard disk, and it could run DOS device drivers. This did OK. IBM did DOS 4. Bigger, but with big disk support, and a GUI app launcher/file manager. DR leapfrogged with DR-DOS 5: all that, but smaller, with built-in memory management. A brief arms race ended with Win95 which bundled MS-DOS and so killed the DOS market. Meantime, DR took the better DOS compatibility and made Multiuser DOS, which did well and throve for decades. Here's a history I did 4Y ago: https://www.theregister.com/software/2022/08/04/the-many-derivatives-of-the-cp/m-operating-system/1383457 https://www.theregister.com/software/2022/08/04/the-many-der...

by iqp 2mo ago

dboreham 2mo ago

Not 386 though.

codebje 2mo ago

CP/M-86 was definitely a thing, but CP/M-386 was not. By the time the 386 existed, DRI had dropped the CP/M name in favour of Concurrent DOS - though they had MS-DOS compatibility in Concurrent CP/M - and, as you say, eventually renamed it to DR-DOS. Much as I loved DR-DOS, it did have occasional compatibility hiccups.

m132 2mo ago
Chances are those hiccups weren't without a reason! https://en.wikipedia.org/wiki/Jim_Allchin#Controversies https://en.wikipedia.org/wiki/Jim_Allchin#Controversies
- codebje 2mo ago
  Also, it was super common practice to just go direct to undocumented internals. You didn't have a clean API to duplicate, you had all the untamed glory of a CPU with no MMU to deal with, and all the programs that did shonky things because they worked.
lproven 2mo ago
> Much as I loved DR-DOS, it did have occasional compatibility hiccups. Because MS carefully built them. This was proved in court. The developers who built the incompatibilities signed their work with their initials: AARD. https://en.wikipedia.org/wiki/AARD_code https://en.wikipedia.org/wiki/AARD_code How it was found: https://www.geoffchappell.com/notes/windows/archive/aard/index.htm https://www.geoffchappell.com/notes/windows/archive/aard/ind...

deleted 2mo ago

[deleted]

Brian_K_White 2mo ago

cp/m-86 targets 8086, which is no more useful or relevant to 386 protected mode than the original z80 version. Did you think they just picked the 68k version at random?

skissane 2mo ago
> cp/m-86 targets 8086, which is no more useful or relevant to 386 protected mode than the original z80 version. Did you think they just picked the 68k version at random? The big reason for picking the 68K version is it was mainly written in C (initially in Pascal, but they later switched to C.) By contrast, the more famous 8080 versions were largely written in assembly, as was the 8086 version. Well, CP/M-80 1.x was mostly written in PL/M, a dialect of PL/I developed by Gary Kildall, but CP/M-80 2.x+ was rewritten in assembly for speed; PL/M was still used for some of the utilities. Obviously, C compilers are much easier to come by nowadays than PL/M compilers are.

p_l 2mo ago

MS-DOS truly beat CP/M-86 when it extended the APIs and features in PC/MS-DOS 2.0 (heavily inspired by Xenix), like hierarchical file system. From then on, applications would target MS-DOS in addition to the curse of being too IBM PC specific

pjmlp 1mo ago
For a while Microsoft was betting their future with Xenix, what an alternative reality that could have been.
- p_l 1mo ago
  I somewhat suspect that if not for multiple materials (not from MS) promoting deep dependency on IBM PC specifics, it might have worked out.

lproven 2mo ago

I don't want to just quibble for the fun of it but so much more of this is wrong than right that it's downright misleading. > I'm pretty sure CP/M 86 was already a thing. Yes it was. Launched after the IBM PC, though, which is why SCP wrote QDOS which they licensed to MS and became MS-DOS. How and why it was late: https://nemanjatrifunovic.substack.com/p/the-late-arrival-of-16-bit-cpm https://nemanjatrifunovic.substack.com/p/the-late-arrival-of... > I believe there was even Concurrent CP/M 86 There was. And then CCPM-286 and CCPM-386. > which let you run up to 4 (or more?) virtual sessions concurrently On the console -- but the selling point was that you could also attach dumb terminals to the serial ports and they could run DOS apps too. So you had a cheap multiuser box, where adding 3 or 4 or 8 more users cost about 10% as much as a network with 3 or 4 or 8 more client PCs. > Light years ahead of MS-DOS but nobody wanted it, No, not at all. One descendant is still supported today, some 45 years later. https://tgcs04.toshibacommerce.com/cs/groups/internet/documents/document/dg9z/njyw/~edisp/prod.tos660737.pdf https://tgcs04.toshibacommerce.com/cs/groups/internet/docume... > so DRI dumbed it down and added MS-DOS compatibility No, not even slightly. > and re-released as DR-DOS (still superior to MS-DOS though). Not a fair description at all. Here's how it went: MS-DOS beat it to market. So, DR brought multitasking and multiuser from MP/M to turn CP/M-86 into Concurrent CP/M: CCP/M-86 MS-DOS did great. So, lots of apps. So, DR added DOS compatibility to CCP/M. It also did a single-user OS, called DR DOS Plus. Oversimplification: this was a single-user non-multitasking CP/M-86 that read/wrote FAT and could run DOS apps. Intel did a new chip, the 80286. DR ported to it. A native protect-mode 286 OS, which used new 286 features to pre-emptively multitask DOS apps. Intel removed those features before it launched the 286. This killed DR's new OS. So, it refocused: it temporarily dropped DOS compatibility, and sold it as an RTOS instead, with a multitasking version of GEM as its GUI. Intel put the features back and Concurrent DOS 286 became a product but it was too late. This was a better OS/2 before OS/2 1.0 launched. Intel put DOS multitasking into hardware in the 386. DR rewrote CDOS286 in C creating CDOS386. This had really good DOS compatibility. So DR updated DOS Plus to make DR-DOS: a superset of MS-DOS 3.3, with FAT16 for big hard disk, and it could run DOS device drivers. This did OK. IBM did DOS 4. Bigger, but with big disk support, and a GUI app launcher/file manager. DR leapfrogged with DR-DOS 5: all that, but smaller, with built-in memory management. A brief arms race ended with Win95 which bundled MS-DOS and so killed the DOS market. Meantime, DR took the better DOS compatibility and made Multiuser DOS, which did well and throve for decades. Here's a history I did 4Y ago: https://www.theregister.com/software/2022/08/04/the-many-derivatives-of-the-cp/m-operating-system/1383457 https://www.theregister.com/software/2022/08/04/the-many-der...