8 ms·

LokiOS: A new version of CP/M 2.2, written from scratch

98 points by JPLeRouzic 4y ago

lockhouse 4y ago
CP/M is a bit before my time, but why was it so wildly popular compared to its contemporaries? Was there any technical reason or was it just available and easy to license for the different microcomputers that came to market at the time? It’s interesting that some of CP/M’s underlying ideas are part of Windows 11 today, such as drive letters.
- mistrial9 4y ago
  the collection of hardware parts in those days was really different. I imagine that simply disposing of the dependencies on a hundred "standard" parts of a modern PC motherboard in the source code, is a win. So it is not better to go back to CP/M for some architectural reason, it is a win to get-rid-of the intrusive and bulky, and patented, parts in modern OS.
- karmakaze 4y ago
  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
- whartung 4y ago
  CP/M is popular because its requirements are dirt simple, and it has a lot of software that still runs. It's popular because, unlike IBM PCs, the hardware was diverse, and the software has to cope with that. Now, while MS-DOS is very CP/M-esque in its design, the truth is that most MS-DOS software is actually PC software. It assumes the PC hardware. Most major MS-DOS applications skipped the MS-DOS driver part and just went straight into the hardware. Today that means if you want an "MS-DOS" machine, you really need a PC with all of its hardware, its graphics, its ports in the right place, etc. In contrast to CP/M. It requires a block device of some kind (i.e. a disk drive), and a console of some kind (typically, but not necessarily, a serial terminal). While some applications did route around the BIOS and BDOS in CP/M, most did not. CP/M was quite portable across a crazy range of hardware. Porting a CP/M BIOS is a nice engineering and assembly language challenge for anyone willing to take it on, depending on their hardware environment. Today, anyone with a Z80 chip, a RAM chip, and some paperclips to wire it all together can get a device that will run Wordstar. That flexibility makes CP/M very popular with retro enthusiasts today. It's easy to find dongle sized computers for $50 running CP/M on eBay. It's also easy to find full through hole kits of parts and PC boards to make your own. Or, grab a Z80 CPU and Peripheral manual, a copy of KiCad, some parts and breadboards and go to town. Having your creating run Wordstar beats blinking LEDs any day of the week.
  - nineteen999 4y ago
    > Porting a CP/M BIOS is a nice engineering and assembly language challenge for anyone willing to take it on, depending on their hardware environment. In my case I decided the hardware environment was going to be hosted inside Unreal Engine: https://i.imgur.com/5MDfwKg.png https://i.imgur.com/5MDfwKg.png It's crazy easy to get CP/M running on just about anything with Z80 CPU emulation, and some glue logic to handle reading bytes from a keyboard I/O port, and sending them to a terminal, and reading/writing sectors from a block device. I had to write a VT100 emulator for UE4 but that doesn't take too much work. WordStar: https://i.imgur.com/rIY1he8.png https://i.imgur.com/rIY1he8.png A telnet client (complete with ZMODEM) for accessing BBS's on the Internet: https://i.imgur.com/aSc9VGL.png https://i.imgur.com/aSc9VGL.png Zork I and Rogue: https://i.imgur.com/gnOCp3e.png https://i.imgur.com/gnOCp3e.png
- shrubble 4y ago
  CP/M was well-designed, better than MSDOS. It had terminal capabilities (not to the level of termcap in Unix, but good) which meant that shrinkwrapped software like Wordstar would run on anything with an 8080, Z80, or NEC V20/V30 and CP/M. The Osborne 1's tiny screen was only 50 characters wide instead of 80, but software still ran on it. It hit the sweet spot of abstraction for its time, and made it easy to write drivers for custom hardware that a new manufacturer might decide to make.
  - spc476 4y ago
    How was it better than MS-DOS?
    - Tor3 4y ago
      One reason is that unlike MS-DOS, the OS is hardware independent, except that an 8080-compatible CPU was needed (8080, z80, some NEC chips etc). Other than that you could use just about anything. It wasn't hard to port (more like transport than port) CP/M to a new system which met the minimum requirements (cpu, some minimum amount of RAM, floppy disks at least, and a TTY or terminal). Very different from MS-DOS, which required a mostly exact PC clone, and it had no provision for moving to another architecture. CP/M came with, among other tools, "MOVECPM", a program to relocate the operating system to a different place in the memory map (and write the result to a new boot floppy or whatever), an Alteration Guide document, and there were various books detailing the process.
      - kjs3 4y ago
        CP/M didn't require a floppy. You could boot it off ROMs, tape or even paper tape (ASR-33s were fun). There's even a RDR: device that was supposed to be used to load from a card reader, tho I confess I never saw that in the wild. MS-DOS was structured the same as CP/M: there was a small-ish machine dependent part you ported (called an 'OEM Adaption Kit' at one time), and a hardware independent kernel. At least through 3.0 and probably later, it did not require a PC clone. It ran on all sorts of non-PC 8088/8086 machines. Ever run MS-DOS on an 80186 with 8" floppies? I have. Now, your apps might not run because of machine level assumptions (video, usually), but MS-DOS did.
- tannhaeuser 4y ago
  Portability before Windows or any other system became mainstream. For example, Hitchhiker's Guide to the Galaxy (the original text adventure) was available on it (and so did early text processors though I personally can't speak with hands-on experience here). Technically, CP/M isn't even an O/S in the "modern" sense taking Unix as a point of reference - Z80 and 8086 didn't even have an MMU so no kernel/userspace memory protection or process isolation. CP/M, like DOS, is rather an extended BIOS with a file system (as it says on the tin: control program for microcomputers) acting as portability lib once a program is loaded, plus a couple of interrupt handlers for screen refresh etc. I guess.
  - varjag 4y ago
    It was an operating system in the sense it abstracted much of the hardware into portable syscalls and came with a set of practical utility programs. Really the only assumption hardware had to conform was a certain memory map layout. Process isolation does not make much sense on a 2mhz 8 bit CPU with 64Kb address space anyway. MS DOS didn't do that either, and there are still modern embedded OSes that don't do process isolation.
    - rbanffy 4y ago
      If you look at some OSs that have been around for a very long time, they are quite minimalistic. While deeply alien to the Unix crowd, OSs like MCP or zOS are remarkably simple in what they do.
- wkat4242 4y ago
  Was it that popular really? Here in Europe I've never seen it in the real world. It was all commodore 64 and other 8-bit or early PC. Even in businesses.
  - fermigier 4y ago
    I was. When, as a kid, I went to computer trade shows in the early 80s, 1/2 of the "business" computers were running CP/M (then switched, almost overnight, to MS-DOS around 1983, IIRC).
  - Doctor_Fegg 4y ago
    Several computers popular in Europe would run it - the Amstrad CPC/PCW series, for example, which between them sold over 10 million units.
  - Tor3 4y ago
    It was definitely popular in Europe, you just had to look at the right places. Both CP/M and the multi-user variant MP/M were used in e.g. accountant offices, and the reason is exactly as an earlier comment said - CP/M and MP/M could run on tons of different hardware, so you could start with choosing which hardware worked best for your use case / office, and then just run CP/M or MP/M with the software you needed. Accounting, for example. I remember visiting an office with 8 terminals connected to an MP/M box - I can't recall at all what that hardware was, except that it was probably built in northern Europe somewhere. I went there because they had accidentally deleted all the files on their harddisk, and needed a rescue.. which wasn't difficult to fix.
- cmrdporcupine 4y ago
  It's just what ran on the various 8080/Z80 machines that flooded the market in the late 70s. There weren't really any alternatives. As for the prevalence of its concepts, Gary Kildall borrowed a lot from minicomputer OSes that he was exposed to early in his career. CP/M brought a lot of the capabilities and styles of those $$$ systems to machines that people could use at home. So I think if you want to see where this style of CLI came from and why those things were popular you might look at DEC TOPS-10... or other "real" minicomputer operating systems that hobbyists coveted but could not afford for themselves. Before standardization around the IBM PC, CP/M was the only way to get that, really. And there were boatloads of these 8080/Z80 systems out there, all sharing some common attributes but not being 100% compatible with each other, so CP/M is what glued them all together until the great wave of the IBM PC overtook them all.
- lproven 4y ago
  > compared to its contemporaries It didn't have any. That's why it thrived. It was the first cross-platform OS for microcomputers. There were other microcomputers, but they didn't have OSes as such: they mostly had a BASIC interpreter in ROM and that was all. And most machines had their own unique implementations of BASIC, all subtly different. In the American market (and only there), Microsoft BASIC was a lowest-common-denominator industry standard, because it was very small and MS made it cheap. It was rubbish, though: no graphics, no sound, no structure, not even IF...THEN...ELSE. In the rest of the world, vendors competed for who could offer the best BASIC... and in the end, Acorn won, with BBC BASIC, which was the best by far of any early 1980s micro. Acorn went on to invent the ARM processor. However, all the different BASICs made all the machines software incompatible. CP/M was a DOS: a disk operating system. You needed a disk drive, and ideally 2. That was expensive, so CP/M ran on expensive micros in the small-business market: often they cost thousands of £/$ while home computers sold for hundreds of £/$. In that space, CP/M had no competition until MS-DOS came along, for the newer and more powerful 16-bit Intel 8088 and 8086 chips.
  - goosedragons 4y ago
    If the UK is "the rest of the world" sure. Microsoft BASICs served as the foundation for a lot of home computer BASICs, Commodore's, Apple's, MSX, PC-8800's. C64's were very popular in parts of Europe too like Germany, not just the US.
    - lproven 4y ago
      Not just the UK. France had some interesting home micros, and of course Minitel. Japan had some amazing machines, and MSX did some stuff that no other 8-bits ever did. Behind the iron curtain there was a ton of R&D, including legions of clones, but also PDP-11 home computers, machines that used trinary instead of binary and all sorts of exotica. In the Southern hemisphere, Australia and several big Latin American countries had their own industries, due to the costs of imports.
      - goosedragons 4y ago
- fastaguy88 4y ago
  Mostly because there were no contemporaries. HDOS (Heathkit DOS) was an alternative for a while (only on Heath/Zenith) but almost all third party packages were for CP/M. It is hard to explain the hardware diversity, even in the 8080/Z80 universe, but relative lack of software diversity (there was no IBM PC standard). But if you wanted to run WordStar, CP/M was the only option.
- BirAdam 4y ago
  8 bit CPUs are seriously limited and the OS on them needed to be user friendly and lean. CP/M mostly covered that. The other thing is, many early computer users also had used mainframes, with DEC being exceedingly popular in colleges and universities. Among the operating systems for DEC’s machines was TOPS-10, from which CP/M drew a ton of inspiration. CP/M being similar to TOPS in many ways made it easy for people to pick up. There’s also timing. CP/M had serious first mover advantage.
- themadturk 4y ago
  For one thing, there weren't many contemporaries. Its biggest advantage was its ubiquity. It came out years before MS-DOS. Some microcomputer manufacturers had their own DOSs, but CP/M needed relatively little customization to run on any machine that had an 8080 or Z80-compatible processor, and in most cases it ran better and faster than the hardware manufacturer's DOS. Microsoft's first hardware product, the Z80 Softcard for the Apple II, was a bestselling product because it gave the Apple an 80 column display and CP/M 2.2 all in one package.
askvictor 4y ago
I had assumed the name was from the 80s-bureaucracy aesthetic of the Loki TV series; TIL there was a (proposed) computer called Loki at that time.
fermigier 4y ago
I find this project very intriguing (besides the fact that, despite being, or at least having been, a big Sir Clive fan, I had never heard of "project Loki"). However, it's disappointing that the author didn't publish its source code.
- lproven 4y ago
  Really?! Wow. It was very famous in the Sinclair community of the time. The last new computers from Sinclair Research were the QL (a 680xx home computer launched two weeks before the Mac) and the Spectrum 128, which used a design partly from Investronica in Spain, which tragically didn't incorporate the improvements from Timex in the USA -- it didn't have the extra graphics modes, which the Spectrum desperately needed, and it didn't have joystick ports or a cartridge slot. (Those appeared in the ZX Interface 2, of course.) The two planned machines that Sinclair was talking about were the Pandora and Loki. Pandora was to be a Z80-based laptop -- and bear in mind, at this time, laptops did not really exist yet. Sir Clive's second computer company did launch a derivative of this idea: the Cambridge Computers Z88. I have one. It's a lovely machine, hindered by nonstandard storage slots (because the standards didn't exist yet), and an awkward way of getting documents off the machine: RS-232 serial. (The better way, IMHO, is what Alphasmart did later: make the portable appear as a keyboard, so it can just type your documents into any computer with the right keyboard port, whatever OS or apps you are running.) The Z88 does show that Sinclair learned from his mistakes: it has its own proprietary OS, OZ, which is still in development -- a new version, 5.0, is in beta. https://cambridgez88.jira.com/wiki/spaces/OZ/overview https://cambridgez88.jira.com/wiki/spaces/OZ/overview But on top of OZ it runs the standard Z80 edition of BBC BASIC. The other machine, the Loki, was to be an all-singing all-dancing games machine, and it never happened in any form. https://en.wikipedia.org/wiki/Loki_(computer) https://en.wikipedia.org/wiki/Loki_(computer)
  - cstross 4y ago
    As an aside, I gather than CP/M+ (aka CP/M 3.0) runs quite well on the Spectrum Next and is due to be available on the Spectrum Next Issue 2 (whenever they get hold of the FPGAs the project is hung up on). And the Next looks a whole lot like Loki, except with a gonzo modern FPGA pretending to be a really fast Z80, SD card support, and a Raspberry Pi Zero as a GPU(!). It even costs about the same as an original Spectrum 16K did in 1982, adjusted for 40 years of inflation. https://www.kickstarter.com/projects/spectrumnext/zx-spectrum-next-issue-2 https://www.kickstarter.com/projects/spectrumnext/zx-spectru...
rbanffy 4y ago
I love the idea of "modern" CP/M and to see how far an old and minimalistic OS like that can be pushed on current tech.
- fentonc 4y ago
  I built a 16-core Z80 laptop running CP/NOS (the networked version of CP/M 2.2) - it's surprisingly great and useable: http://www.chrisfenton.com/the-zedripper-part-1/ http://www.chrisfenton.com/the-zedripper-part-1/ It's like a windowed, multi-tasking environment where each process actually gets its own dedicated CPU/memory/display hardware and can run fully independent of the others.
  - LoganDark 4y ago
    Holy hell, that's amazing!!
  - CodeWriter23 4y ago
    Is CP/NET reliable on your cluster? Way back in the day, when I worked at an outfit named ACE on the then-dominant solution for multiprocessor CP/M dpc/os, we evaluated CP/NET and found it unsuitable as a daily driver due to a lot of crashing.
    - fentonc 4y ago
      Neat - I had never heard of ACE. In my (fairly limited) experience it works fine, although running the cores at 140 MHz (and the network) forgives a lot of sins. I actually wrote my CP/NET server as a regular CP/M application in Turbo Pascal, so I can't speak to other server solutions. The idea behind my ZedRipper was to basically turn a 'multi-user' CP/M system into a single-user/multi-tasking system, and it worked better than expected.
  - kjs3 4y ago
    I think it was Cromenco that had a setup where you had a 'master' S-100 CP/M CPU board that managed mass storage, printers and other things, and 'subordinate' S-100 cards that had CPU, memory and SIO. Each user would be dedicated a sub card and terminal, running their own full version of CP/M, and the master mediated access to shared resources. Very popular in small office settings for a while.
timonoko 4y ago
This sucks. Everybody knows that CP/M was written in PL/M, which was its one and only good feature. It was reasonably easy to extend to various projects. Creepiest thing was that Nokia's massive multiprocessor telephone exchange from 1980 was written in PL/M. And CP/M also visible at operators console with floppy disk and other shit.
- macintux 4y ago
  A: not everyone knows. B: it’s possible, even recommended, to express disappointment and talk about the virtues of the original design without saying this “sucks”
  - timonoko 4y ago
    But it does suck. Downvote all you want.
    - themadturk 4y ago
      But it worked, so it can't have sucked too badly.
- timonoko 4y ago
  "Creepies Thing" because Swedish Ericsson made already their exchanges with super high level languages like Erlang. Very embarrassing, but I could not move to Sweden, because unsolved tax issues from 1975.

98 points by JPLeRouzic 4y ago

CP/M is a bit before my time, but why was it so wildly popular compared to its contemporaries? Was there any technical reason or was it just available and easy to license for the different microcomputers that came to market at the time? It’s interesting that some of CP/M’s underlying ideas are part of Windows 11 today, such as drive letters.

mistrial9 4y ago
the collection of hardware parts in those days was really different. I imagine that simply disposing of the dependencies on a hundred "standard" parts of a modern PC motherboard in the source code, is a win. So it is not better to go back to CP/M for some architectural reason, it is a win to get-rid-of the intrusive and bulky, and patented, parts in modern OS.
karmakaze 4y ago
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
whartung 4y ago
CP/M is popular because its requirements are dirt simple, and it has a lot of software that still runs. It's popular because, unlike IBM PCs, the hardware was diverse, and the software has to cope with that. Now, while MS-DOS is very CP/M-esque in its design, the truth is that most MS-DOS software is actually PC software. It assumes the PC hardware. Most major MS-DOS applications skipped the MS-DOS driver part and just went straight into the hardware. Today that means if you want an "MS-DOS" machine, you really need a PC with all of its hardware, its graphics, its ports in the right place, etc. In contrast to CP/M. It requires a block device of some kind (i.e. a disk drive), and a console of some kind (typically, but not necessarily, a serial terminal). While some applications did route around the BIOS and BDOS in CP/M, most did not. CP/M was quite portable across a crazy range of hardware. Porting a CP/M BIOS is a nice engineering and assembly language challenge for anyone willing to take it on, depending on their hardware environment. Today, anyone with a Z80 chip, a RAM chip, and some paperclips to wire it all together can get a device that will run Wordstar. That flexibility makes CP/M very popular with retro enthusiasts today. It's easy to find dongle sized computers for $50 running CP/M on eBay. It's also easy to find full through hole kits of parts and PC boards to make your own. Or, grab a Z80 CPU and Peripheral manual, a copy of KiCad, some parts and breadboards and go to town. Having your creating run Wordstar beats blinking LEDs any day of the week.
- nineteen999 4y ago
  > Porting a CP/M BIOS is a nice engineering and assembly language challenge for anyone willing to take it on, depending on their hardware environment. In my case I decided the hardware environment was going to be hosted inside Unreal Engine: https://i.imgur.com/5MDfwKg.png https://i.imgur.com/5MDfwKg.png It's crazy easy to get CP/M running on just about anything with Z80 CPU emulation, and some glue logic to handle reading bytes from a keyboard I/O port, and sending them to a terminal, and reading/writing sectors from a block device. I had to write a VT100 emulator for UE4 but that doesn't take too much work. WordStar: https://i.imgur.com/rIY1he8.png https://i.imgur.com/rIY1he8.png A telnet client (complete with ZMODEM) for accessing BBS's on the Internet: https://i.imgur.com/aSc9VGL.png https://i.imgur.com/aSc9VGL.png Zork I and Rogue: https://i.imgur.com/gnOCp3e.png https://i.imgur.com/gnOCp3e.png
shrubble 4y ago
CP/M was well-designed, better than MSDOS. It had terminal capabilities (not to the level of termcap in Unix, but good) which meant that shrinkwrapped software like Wordstar would run on anything with an 8080, Z80, or NEC V20/V30 and CP/M. The Osborne 1's tiny screen was only 50 characters wide instead of 80, but software still ran on it. It hit the sweet spot of abstraction for its time, and made it easy to write drivers for custom hardware that a new manufacturer might decide to make.
- spc476 4y ago
  How was it better than MS-DOS?
  - Tor3 4y ago
    One reason is that unlike MS-DOS, the OS is hardware independent, except that an 8080-compatible CPU was needed (8080, z80, some NEC chips etc). Other than that you could use just about anything. It wasn't hard to port (more like transport than port) CP/M to a new system which met the minimum requirements (cpu, some minimum amount of RAM, floppy disks at least, and a TTY or terminal). Very different from MS-DOS, which required a mostly exact PC clone, and it had no provision for moving to another architecture. CP/M came with, among other tools, "MOVECPM", a program to relocate the operating system to a different place in the memory map (and write the result to a new boot floppy or whatever), an Alteration Guide document, and there were various books detailing the process.
    - kjs3 4y ago
      CP/M didn't require a floppy. You could boot it off ROMs, tape or even paper tape (ASR-33s were fun). There's even a RDR: device that was supposed to be used to load from a card reader, tho I confess I never saw that in the wild. MS-DOS was structured the same as CP/M: there was a small-ish machine dependent part you ported (called an 'OEM Adaption Kit' at one time), and a hardware independent kernel. At least through 3.0 and probably later, it did not require a PC clone. It ran on all sorts of non-PC 8088/8086 machines. Ever run MS-DOS on an 80186 with 8" floppies? I have. Now, your apps might not run because of machine level assumptions (video, usually), but MS-DOS did.
tannhaeuser 4y ago
Portability before Windows or any other system became mainstream. For example, Hitchhiker's Guide to the Galaxy (the original text adventure) was available on it (and so did early text processors though I personally can't speak with hands-on experience here). Technically, CP/M isn't even an O/S in the "modern" sense taking Unix as a point of reference - Z80 and 8086 didn't even have an MMU so no kernel/userspace memory protection or process isolation. CP/M, like DOS, is rather an extended BIOS with a file system (as it says on the tin: control program for microcomputers) acting as portability lib once a program is loaded, plus a couple of interrupt handlers for screen refresh etc. I guess.
- varjag 4y ago
  It was an operating system in the sense it abstracted much of the hardware into portable syscalls and came with a set of practical utility programs. Really the only assumption hardware had to conform was a certain memory map layout. Process isolation does not make much sense on a 2mhz 8 bit CPU with 64Kb address space anyway. MS DOS didn't do that either, and there are still modern embedded OSes that don't do process isolation.
  - rbanffy 4y ago
    If you look at some OSs that have been around for a very long time, they are quite minimalistic. While deeply alien to the Unix crowd, OSs like MCP or zOS are remarkably simple in what they do.
wkat4242 4y ago
Was it that popular really? Here in Europe I've never seen it in the real world. It was all commodore 64 and other 8-bit or early PC. Even in businesses.
- fermigier 4y ago
  I was. When, as a kid, I went to computer trade shows in the early 80s, 1/2 of the "business" computers were running CP/M (then switched, almost overnight, to MS-DOS around 1983, IIRC).
- Doctor_Fegg 4y ago
  Several computers popular in Europe would run it - the Amstrad CPC/PCW series, for example, which between them sold over 10 million units.
- Tor3 4y ago
  It was definitely popular in Europe, you just had to look at the right places. Both CP/M and the multi-user variant MP/M were used in e.g. accountant offices, and the reason is exactly as an earlier comment said - CP/M and MP/M could run on tons of different hardware, so you could start with choosing which hardware worked best for your use case / office, and then just run CP/M or MP/M with the software you needed. Accounting, for example. I remember visiting an office with 8 terminals connected to an MP/M box - I can't recall at all what that hardware was, except that it was probably built in northern Europe somewhere. I went there because they had accidentally deleted all the files on their harddisk, and needed a rescue.. which wasn't difficult to fix.
cmrdporcupine 4y ago
It's just what ran on the various 8080/Z80 machines that flooded the market in the late 70s. There weren't really any alternatives. As for the prevalence of its concepts, Gary Kildall borrowed a lot from minicomputer OSes that he was exposed to early in his career. CP/M brought a lot of the capabilities and styles of those $$$ systems to machines that people could use at home. So I think if you want to see where this style of CLI came from and why those things were popular you might look at DEC TOPS-10... or other "real" minicomputer operating systems that hobbyists coveted but could not afford for themselves. Before standardization around the IBM PC, CP/M was the only way to get that, really. And there were boatloads of these 8080/Z80 systems out there, all sharing some common attributes but not being 100% compatible with each other, so CP/M is what glued them all together until the great wave of the IBM PC overtook them all.
lproven 4y ago
> compared to its contemporaries It didn't have any. That's why it thrived. It was the first cross-platform OS for microcomputers. There were other microcomputers, but they didn't have OSes as such: they mostly had a BASIC interpreter in ROM and that was all. And most machines had their own unique implementations of BASIC, all subtly different. In the American market (and only there), Microsoft BASIC was a lowest-common-denominator industry standard, because it was very small and MS made it cheap. It was rubbish, though: no graphics, no sound, no structure, not even IF...THEN...ELSE. In the rest of the world, vendors competed for who could offer the best BASIC... and in the end, Acorn won, with BBC BASIC, which was the best by far of any early 1980s micro. Acorn went on to invent the ARM processor. However, all the different BASICs made all the machines software incompatible. CP/M was a DOS: a disk operating system. You needed a disk drive, and ideally 2. That was expensive, so CP/M ran on expensive micros in the small-business market: often they cost thousands of £/$ while home computers sold for hundreds of £/$. In that space, CP/M had no competition until MS-DOS came along, for the newer and more powerful 16-bit Intel 8088 and 8086 chips.
- goosedragons 4y ago
  If the UK is "the rest of the world" sure. Microsoft BASICs served as the foundation for a lot of home computer BASICs, Commodore's, Apple's, MSX, PC-8800's. C64's were very popular in parts of Europe too like Germany, not just the US.
  - lproven 4y ago
    Not just the UK. France had some interesting home micros, and of course Minitel. Japan had some amazing machines, and MSX did some stuff that no other 8-bits ever did. Behind the iron curtain there was a ton of R&D, including legions of clones, but also PDP-11 home computers, machines that used trinary instead of binary and all sorts of exotica. In the Southern hemisphere, Australia and several big Latin American countries had their own industries, due to the costs of imports.
    - goosedragons 4y ago
fastaguy88 4y ago
Mostly because there were no contemporaries. HDOS (Heathkit DOS) was an alternative for a while (only on Heath/Zenith) but almost all third party packages were for CP/M. It is hard to explain the hardware diversity, even in the 8080/Z80 universe, but relative lack of software diversity (there was no IBM PC standard). But if you wanted to run WordStar, CP/M was the only option.
BirAdam 4y ago
8 bit CPUs are seriously limited and the OS on them needed to be user friendly and lean. CP/M mostly covered that. The other thing is, many early computer users also had used mainframes, with DEC being exceedingly popular in colleges and universities. Among the operating systems for DEC’s machines was TOPS-10, from which CP/M drew a ton of inspiration. CP/M being similar to TOPS in many ways made it easy for people to pick up. There’s also timing. CP/M had serious first mover advantage.
themadturk 4y ago
For one thing, there weren't many contemporaries. Its biggest advantage was its ubiquity. It came out years before MS-DOS. Some microcomputer manufacturers had their own DOSs, but CP/M needed relatively little customization to run on any machine that had an 8080 or Z80-compatible processor, and in most cases it ran better and faster than the hardware manufacturer's DOS. Microsoft's first hardware product, the Z80 Softcard for the Apple II, was a bestselling product because it gave the Apple an 80 column display and CP/M 2.2 all in one package.

askvictor 4y ago

I had assumed the name was from the 80s-bureaucracy aesthetic of the Loki TV series; TIL there was a (proposed) computer called Loki at that time.

fermigier 4y ago

I find this project very intriguing (besides the fact that, despite being, or at least having been, a big Sir Clive fan, I had never heard of "project Loki"). However, it's disappointing that the author didn't publish its source code.

lproven 4y ago
Really?! Wow. It was very famous in the Sinclair community of the time. The last new computers from Sinclair Research were the QL (a 680xx home computer launched two weeks before the Mac) and the Spectrum 128, which used a design partly from Investronica in Spain, which tragically didn't incorporate the improvements from Timex in the USA -- it didn't have the extra graphics modes, which the Spectrum desperately needed, and it didn't have joystick ports or a cartridge slot. (Those appeared in the ZX Interface 2, of course.) The two planned machines that Sinclair was talking about were the Pandora and Loki. Pandora was to be a Z80-based laptop -- and bear in mind, at this time, laptops did not really exist yet. Sir Clive's second computer company did launch a derivative of this idea: the Cambridge Computers Z88. I have one. It's a lovely machine, hindered by nonstandard storage slots (because the standards didn't exist yet), and an awkward way of getting documents off the machine: RS-232 serial. (The better way, IMHO, is what Alphasmart did later: make the portable appear as a keyboard, so it can just type your documents into any computer with the right keyboard port, whatever OS or apps you are running.) The Z88 does show that Sinclair learned from his mistakes: it has its own proprietary OS, OZ, which is still in development -- a new version, 5.0, is in beta. https://cambridgez88.jira.com/wiki/spaces/OZ/overview https://cambridgez88.jira.com/wiki/spaces/OZ/overview But on top of OZ it runs the standard Z80 edition of BBC BASIC. The other machine, the Loki, was to be an all-singing all-dancing games machine, and it never happened in any form. https://en.wikipedia.org/wiki/Loki_(computer) https://en.wikipedia.org/wiki/Loki_(computer)
- cstross 4y ago
  As an aside, I gather than CP/M+ (aka CP/M 3.0) runs quite well on the Spectrum Next and is due to be available on the Spectrum Next Issue 2 (whenever they get hold of the FPGAs the project is hung up on). And the Next looks a whole lot like Loki, except with a gonzo modern FPGA pretending to be a really fast Z80, SD card support, and a Raspberry Pi Zero as a GPU(!). It even costs about the same as an original Spectrum 16K did in 1982, adjusted for 40 years of inflation. https://www.kickstarter.com/projects/spectrumnext/zx-spectrum-next-issue-2 https://www.kickstarter.com/projects/spectrumnext/zx-spectru...

rbanffy 4y ago

I love the idea of "modern" CP/M and to see how far an old and minimalistic OS like that can be pushed on current tech.

fentonc 4y ago
I built a 16-core Z80 laptop running CP/NOS (the networked version of CP/M 2.2) - it's surprisingly great and useable: http://www.chrisfenton.com/the-zedripper-part-1/ http://www.chrisfenton.com/the-zedripper-part-1/ It's like a windowed, multi-tasking environment where each process actually gets its own dedicated CPU/memory/display hardware and can run fully independent of the others.
- LoganDark 4y ago
  Holy hell, that's amazing!!
- CodeWriter23 4y ago
  Is CP/NET reliable on your cluster? Way back in the day, when I worked at an outfit named ACE on the then-dominant solution for multiprocessor CP/M dpc/os, we evaluated CP/NET and found it unsuitable as a daily driver due to a lot of crashing.
  - fentonc 4y ago
    Neat - I had never heard of ACE. In my (fairly limited) experience it works fine, although running the cores at 140 MHz (and the network) forgives a lot of sins. I actually wrote my CP/NET server as a regular CP/M application in Turbo Pascal, so I can't speak to other server solutions. The idea behind my ZedRipper was to basically turn a 'multi-user' CP/M system into a single-user/multi-tasking system, and it worked better than expected.
- kjs3 4y ago
  I think it was Cromenco that had a setup where you had a 'master' S-100 CP/M CPU board that managed mass storage, printers and other things, and 'subordinate' S-100 cards that had CPU, memory and SIO. Each user would be dedicated a sub card and terminal, running their own full version of CP/M, and the master mediated access to shared resources. Very popular in small office settings for a while.

timonoko 4y ago

This sucks. Everybody knows that CP/M was written in PL/M, which was its one and only good feature. It was reasonably easy to extend to various projects. Creepiest thing was that Nokia's massive multiprocessor telephone exchange from 1980 was written in PL/M. And CP/M also visible at operators console with floppy disk and other shit.

macintux 4y ago
A: not everyone knows. B: it’s possible, even recommended, to express disappointment and talk about the virtues of the original design without saying this “sucks”
- timonoko 4y ago
  But it does suck. Downvote all you want.
  - themadturk 4y ago
    But it worked, so it can't have sucked too badly.
timonoko 4y ago
"Creepies Thing" because Swedish Ericsson made already their exchanges with super high level languages like Erlang. Very embarrassing, but I could not move to Sweden, because unsolved tax issues from 1975.