17 ms·

CP/M is really open-source now

393 points by jstanley 4y ago

gjvc 4y ago
Symbolics next, please!
- Tomte 4y ago
  Good luck hoping for that! They sold their "first .com domain" to some guy who… seems to be a domain squatter (although he writes a lot about not being one). Companies that eager to make a quick buck are usually not the ones open-sourcing their stuff.
  - rbanffy 4y ago
    It certainly feels like the people in the Amiga space. They'll milk their cow until its last drop of blood.
    - orangepurple 4y ago
      I'm not familiar with this culture. Can you expand on it?
      - lproven 4y ago
        I would guess that they mean Hyperion, which owns the name and IP. It develops AmigaOS 4.x for PowerPC Amigas: https://www.hyperion-entertainment.com/index.php/where-to-buy/direct-downloads/174-amigaos-41-final-edition-for-classic https://www.hyperion-entertainment.com/index.php/where-to-bu... And also AmigaOS 3.2 for old 680x0 Amigas: https://www.hyperion-entertainment.com/index.php/news/1-latest-news/290-amigaos-42-for-all-classic-amigas-released-and-available https://www.hyperion-entertainment.com/index.php/news/1-late...
  - gjvc 4y ago
    this is the guy who presumably sold the original domain, http://www.symbolics-dks.com/ http://www.symbolics-dks.com/
- rbanffy 4y ago
  That'd be INSANELY cool. Let's go a bit further then. Next, open source SCOPE, NOS/VE and PLATO!
  - cestith 4y ago
    For nostalgia purposes, I'd like to see MUSIC & MUSIC/SP source with a fully open license. It was on our mainframe at uni in the 1990s.
    - rbanffy 4y ago
      Do we have a wishlist for version 2.4? I'd go for s390x and 64-bit addressing support.
      - cestith 4y ago
        I haven't interacted with the system in decades. I have some wishlist items from since then but I really need to give the demo some time to have an updated list. Those two alone seem sufficient for a release though.
        rbanffy 4y ago
        McGill will need to open-source it first. I'd suggest AGPL for the license ;-)
skywal_l 4y ago
I remember, when I was a kid, having a CP/M diskette for the Amstrad CPC. It was provided with the machine. Every now and then I would try it out, not really understanding what it was about. Years later I learned, reading about it, that it was some sort of "professional" OS on which productivity software would be used. Does anyone actually used that OS on CPC or any other 8bits machine of the 80s to do anything remotely useful? Genuinely interested.
- jstanley 4y ago
  I haven't used a real 80s computer (except in a museum). I've used CP/M a fair amount on an RC2014[0], but never for anything you might describe as "useful". [0] https://rc2014.co.uk/ https://rc2014.co.uk/
  - stevekemp 4y ago
    Same here, I've been running a single-board Z80-based system with 64k and CP/M 2.x I worked my way through the various infocom adventures, and even wrote my own trivial text-based adventure game in Z80 assembly language - later porting it to the ZX Spectrum (which was the actual computer of my youth). It's fun to play with these systems, and I've rebuilt the CP/M from sources a few times to add simple changes and new built-in commands.
    - jstanley 4y ago
      Turns out I've actually played your text adventure on my RC2014, and sent you a couple of trivial pull requests :). I had a go at Zork too but found it far too complicated to be playable. I might have persevered if the directions were consistent, but it's just too hard to map everything out when you leave a room by going east but then to go back to where you came you need to go south.
      - stevekemp 4y ago
        Small world, thanks for your contributions! It wasn't very complicated, but I enjoyed putting it together and playing it with our child. For me the Hitchhikers Guide was something I'd been wanting to complete - having played it for the first time a little after the release -and I did get there in the end.
linuxhansl 4y ago
My foray into disk-based operation systems. Oh, sooo many years ago. A friend of mine had it, and I would ride my bike through country roads as a kid to play around with it.
zabzonk 4y ago
Lots of the source of CP/M came with the distribution, and it wasn't hard to dis-assemble specific bits you were interested in. Some CP/M software (I'm thinking of WordStar specifically here, but no doubt others) almost required you to write a keyboard and display handler in Z80/8080 machine code to get decent performance over the generic CP/M code - been there on Research Machines 380Zs.
- jstanley 4y ago
  Source has been available for years, it just hasn't been clear whether it was legal to redistribute it. Now it's clear :).
  - bornfreddy 4y ago
    ...clearer (if at all). The proper license, whatever it is, is still missing. Sorry. :)
doctor_eval 4y ago
Why about MP/M. I loved having more than one user on a 8080.
- dfawcus 4y ago
  Source and binaries are on the site: http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html http://www.cpm.z80.de/binary.html#operating http://www.cpm.z80.de/binary.html#operating Search for MP
  - doctor_eval 4y ago
    That is so cool. I'm not really a retro-computing guy and am unlikely to ever run this code, but it does bring back memories of bringing home an old unsold box from work, sitting on the garage floor, writing a program in unfamiliar 8080 mnemonics, and getting two terminals to chat to one another. OTOH it might be fun to get something working on a Z80 SOC. Or something like this https://hackaday.com/2017/01/02/retrocomputing-for-4-with-a-z80/ https://hackaday.com/2017/01/02/retrocomputing-for-4-with-a-... Has anyone ever trans-compiled Z80 assembly to a microcontroller? Is that even a thing?
kriro 4y ago
That is cool news because it's probably a nice starting point for osdev projects. At least more code to read :) I feel like the code was available before and I read parts of it but I may remember it wrong. Edit: Yes it was indeed "just" a license clarification. Link to the source: http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html
usr1106 4y ago
In high school in 1980 we had Commodore PETs. They had no tangible OS, just a BASIC interpreter in ROM. There was an easter egg that made it say Microsoft or wasn't it spelled MicroSoft? Either way a company nobody had ever heard of. CP/M had the aura of being something for real pros. Read some journal articles and it looked really complicated. But without suitable hardware I had never any chance to touch it. In 1983 I went to university where beginner courses happened on VAX/VMS and my definition of "pro" got shifted.
- hdjjhhvvhga 4y ago
  > In high school in 1980 we had Commodore PETs. They had no tangible OS, just a BASIC interpreter in ROM. Five years later the Commodore 128 appeared. It had the best of both worlds: could run all C64 games and CP/M. These were magic times.
  - mongol 4y ago
    I always booted mine while pressing the Commodore key. Waste of money.
    - Cockbrand 4y ago
      With its separate number pad, it looked really grown-up and professional compared to the 64, though. The 128D even more so, with its desktop box, built-in floppy drive and separate keyboard.
      - mongol 4y ago
        Yes I had that one. It was the worst decision of my life. Had I waited 6 months or so, the Amiga 500 would have launched. I got stuck on dead hardware and got hooked off from computers for several years.
        ansible 4y ago
        If it is any consolation, I got started on the Radio Shack Color Computer ecosystem, with the original version the the CoCo3. Back then, there was quite a bit of debate by the mid 1980's about the longevity of 8/16-bit processors like the 6809 and the 6502 / 6510 series. Addressing a maximum of 64KiB of memory back when 4KiB was expensive seemed fine. And due to cost, picking an 8-bit processor for a design in 1980 seemed sensible. But the ability to support up to 1MiB of RAM (eventually) on the 8086 series help insure the platform's longevity, in spite of the horrible segmented memory programming model. Companies like Motorola weren't terribly interested in backwards compatibility, preferring instead to design completely new instruction sets (like the 68K family) for their 32-bit platforms.
pavlov 4y ago
CP/M was the popular operating system that IBM wanted to license for their skunkworks Personal Computer project. But the founder of Digital Research, the company that developed CP/M, was more interested that day in going flying his plane than meeting with corporate men in navy suits. (This may be apocryphal.) IBM turned instead to their second choice, a small company that was supplying BASIC interpreters to many 8-bit micros. The company didn’t actually have a suitable disk operating system product, but the founder knew someone who did. He made a deal to license the source code for a fixed fee and no limitations on redistribution. And that’s how Bill Gates acquired MS-DOS for $50k.
- Neil44 4y ago
  CP/M was nice, it's a shame we got saddled with MS-DOS for decades.
  - pjmlp 4y ago
    Having started my MS-DOS path with version 3.3, and used all MS-DOS versions, also the DR-DOS 5.0 and 6.0 versions, experienced CP/M on the Spectrum +3A, I fail to see how CP/M was better.
    - mongol 4y ago
      Which directory separator did it have?
      - Doctor_Fegg 4y ago
        CP/M didn't have sub-directories, though it did have 16 "user areas" on a disk.
        II2II 4y ago
        MS-DOS did not have directories at first either. It was a feature in version 2.0, when hard drive support was added. Directories seem to have been a foreign concept among early home computer operating systems and I suspect its adoption was driven by the adoption of hard drives. For example, the Apple II did not gain directory support until ProDOS was introduced and the Macintosh only gained folders with the introduction of HFS. I don't recall directories existing for the Commodore 64 either.
timonoko 4y ago
I thought I had CP/M source code for Osborne-1. But no, I have only inch-thick listing of BIOS. And it did not matter, one always used direct Bios-calls for speed. CP/M was not actually needed for this implementation, it could boot on its own: http://timonoko.github.io/Nokolisp.htm http://timonoko.github.io/Nokolisp.htm
lkxijlewlf 4y ago
Slightly off topic: I recall as a youngin watching Gary Kildall on the Computer Chronicles. I was always fascinated by what people were doing with computers. I know it is nostalgia and there's infinitely more to learn about today than there was then, but I do miss that era of computing.
Cockbrand 4y ago
Of course, there's a CP/M emulator in the browser now, so you don't have to dig out your Z80/8080 computer: https://www.tramm.li/i8080/ https://www.tramm.li/i8080/
jhallenworld 4y ago
HP should open OS/8 and RT-11, the two big influences on CP/M. OS/8 is kind of remarkable, running on a system arguably less powerful than the first 8-bit home computers (I would say they are closer to PIC microcontrollers, but with more RAM): https://www.pdp8online.com/os/os8/index.shtml https://www.pdp8online.com/os/os8/index.shtml PDP-8 memory is heavily paged. There are 128 word pages- direct addresses can only reach within the current page, and literals (immediate data including addresses to other pages) have to be allocated out of this current page along with the instructions. Second, there are 4K-word fields. So you need to use far jumps and returns to access outside the current field. This is just like PIC microcontroller pages. OS/8 reserved only two pages for itself. Things like the command interpreter were swapped out to disk or DECTape. https://en.wikipedia.org/wiki/DECtape https://en.wikipedia.org/wiki/DECtape If the application needed device drivers, it got to choose which pages the drivers would occupy- meaning the device drivers had to be written as position independent code. Also I think each driver was limited to two pages..
Barrera 4y ago
> The discussion is not over yet, but we believe this statement is equivalent to the well-known BSD or MIT licenses. That's not now I'd interpret it. "Open Source" in my mind means that the software uses one of the OSI approved licenses. The quoted paragraph: > Let this paragraph represent a right to use, distribute, modify, enhance, and otherwise make available in a nonexclusive manner CP/M and its derivatives. This right comes from the company, DRDOS, Inc.'s purchase of Digital Research, the company and all assets, dating back to the mid-1990’s. DRDOS, Inc. and I, Bryan Sparks, President of DRDOS, Inc. as its representative, is the owner of CP/M and the successor in interest of Digital Research assets. is not even a license in the traditional sense. It defines nothing. Whatever rights it grants do not appear to be transferrable. Worst of all, it does not even mention source code. If the owners of the CP/M source code want to make it open source, what's so hard about attaching the actual MIT or BSD licenses to a source distribution and publishing it?
- nibbleshifter 4y ago
  > what's so hard about attaching the actual MIT or BSD licenses to a source distribution and publishing it? From experience in related things: lawyers.
- zozbot234 4y ago
  This is most likely why the post mentions that "discussion is not over yet". They seem to be quite optimistic that we might be getting a proper FLOSS release.
- Cyberdog 4y ago
  This sort of confusion could have been avoided if they had just said "the source code to this program is now free to distribute under the (MIT|BSD|GPL|etc) license" from the beginning. Nobody knew what exactly the intent of this novel "let this paragraph represent" approach was supposed to be, and now it just sounds like we have a slightly clearer idea. No need to get cutesy with something as important as your license terms, people.
Communitivity 4y ago
I remember CP/M with fondness. My father gave me an Osborne 1 for my first computer when I was 12 (41 years ago). It came with CBASIC2 as well as MBasic, and I managed to find a Lisp (I forget what flavor). To put the Osborne 1 in perspective, the stats: * 64kb memory (yes that's kilobytes) * 2 5 1/4 floppy disks * No hard disk * 5" monochrome green screen monitor * 4 MHz CPU * 37 watt power supply * weighed ~25 pounds
- jfengel 4y ago
  Plus an RS-232 for your modem and an IEEE 488 for your printer. That CPU lacked a multiply instruction, so you had to implement that yourself.
  - veltas 4y ago
    The multiply instructions on later CPUs were implemented as microcode programs on the silicon, so sometimes it was faster to write your own or a specialised routine anyway.
- jahnu 4y ago
  Luxury! https://m.youtube.com/watch?v=ue7wM0QC5LE https://m.youtube.com/watch?v=ue7wM0QC5LE ;)
- OnlyMortal 4y ago
  4mhz CPU? Luxury super computer!
  - varjag 4y ago
    3.5-4Mhz was standard for most Z80 based systems.
    - sedatk 4y ago
      Still, it didn't perform much better than a 1Mhz 6502 due to its design.
cosmiccatnap 4y ago
I'm sorry but it's not on MIT, GNU, or BSD so I would go so far as to say the title is clickbait...like can I take this code and try and get it to work on my x86 machine and then commit my changes under bsd? Probably not Can someone point me to a repo to look at it? I can't find a link and it doesn't show up on Google.
- dboreham 4y ago
  https://github.com/brouhaha/cpm22/blob/master/bdos.asm https://github.com/brouhaha/cpm22/blob/master/bdos.asm from http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html
kazinator 4y ago
> This right comes from the company, DRDOS, Inc.'s purchase of Digital Research, the company and all assets, dating back to the mid-1990’s What the Wikipedia says, if you piece it together is that Bryan Sparks founded Caldera in the mid 1990's, which bought Digital Research. Around the time Caldera went defunct in 2002, Sparks started DeviceLogics which got renamed to DRDOS Inc. So that must have inherited the Caldera assets, including the Digital Research stuff.
smm11 4y ago
So IBM went crazy with CP/M, and Microsoft suffered. We'd now have CP/M 11, and DOS would be open-source now.
- sbuk 4y ago
  In all likelihood in that timeline DOS as we know it wouldn't have existed.
- BirAdam 4y ago
  I am not so certain that it would have made much difference. Microsoft would still have produced both BASIC and Windows, and we may have had the exact same evolution anyway. DigitalResearch's GEM was mired in legal red tape preventing from much evolution. Also, MSDOS is opensource now. https://computerhistory.org/blog/microsoft-ms-dos-early-source-code/?key=microsoft-ms-dos-early-source-code https://computerhistory.org/blog/microsoft-ms-dos-early-sour...
phendrenad2 4y ago
Always excellent when a piece of computing history has it's source made available. Even better when it's provided under a libre license, as this is! CP/M is a powerful example of what you can do without multitasking. The code is also a time capsule of development techniques and styles of the time.
marcodiego 4y ago
Good but 30-40 years too late.

393 points by jstanley 4y ago

gjvc 4y ago

Symbolics next, please!

Tomte 4y ago
Good luck hoping for that! They sold their "first .com domain" to some guy who… seems to be a domain squatter (although he writes a lot about not being one). Companies that eager to make a quick buck are usually not the ones open-sourcing their stuff.
- rbanffy 4y ago
  It certainly feels like the people in the Amiga space. They'll milk their cow until its last drop of blood.
  - orangepurple 4y ago
    I'm not familiar with this culture. Can you expand on it?
    - lproven 4y ago
      I would guess that they mean Hyperion, which owns the name and IP. It develops AmigaOS 4.x for PowerPC Amigas: https://www.hyperion-entertainment.com/index.php/where-to-buy/direct-downloads/174-amigaos-41-final-edition-for-classic https://www.hyperion-entertainment.com/index.php/where-to-bu... And also AmigaOS 3.2 for old 680x0 Amigas: https://www.hyperion-entertainment.com/index.php/news/1-latest-news/290-amigaos-42-for-all-classic-amigas-released-and-available https://www.hyperion-entertainment.com/index.php/news/1-late...
- gjvc 4y ago
  this is the guy who presumably sold the original domain, http://www.symbolics-dks.com/ http://www.symbolics-dks.com/
rbanffy 4y ago
That'd be INSANELY cool. Let's go a bit further then. Next, open source SCOPE, NOS/VE and PLATO!
- cestith 4y ago
  For nostalgia purposes, I'd like to see MUSIC & MUSIC/SP source with a fully open license. It was on our mainframe at uni in the 1990s.
  - rbanffy 4y ago
    Do we have a wishlist for version 2.4? I'd go for s390x and 64-bit addressing support.
    - cestith 4y ago
      I haven't interacted with the system in decades. I have some wishlist items from since then but I really need to give the demo some time to have an updated list. Those two alone seem sufficient for a release though.
      - rbanffy 4y ago
        McGill will need to open-source it first. I'd suggest AGPL for the license ;-)

skywal_l 4y ago

I remember, when I was a kid, having a CP/M diskette for the Amstrad CPC. It was provided with the machine. Every now and then I would try it out, not really understanding what it was about. Years later I learned, reading about it, that it was some sort of "professional" OS on which productivity software would be used. Does anyone actually used that OS on CPC or any other 8bits machine of the 80s to do anything remotely useful? Genuinely interested.

jstanley 4y ago
I haven't used a real 80s computer (except in a museum). I've used CP/M a fair amount on an RC2014[0], but never for anything you might describe as "useful". [0] https://rc2014.co.uk/ https://rc2014.co.uk/
- stevekemp 4y ago
  Same here, I've been running a single-board Z80-based system with 64k and CP/M 2.x I worked my way through the various infocom adventures, and even wrote my own trivial text-based adventure game in Z80 assembly language - later porting it to the ZX Spectrum (which was the actual computer of my youth). It's fun to play with these systems, and I've rebuilt the CP/M from sources a few times to add simple changes and new built-in commands.
  - jstanley 4y ago
    Turns out I've actually played your text adventure on my RC2014, and sent you a couple of trivial pull requests :). I had a go at Zork too but found it far too complicated to be playable. I might have persevered if the directions were consistent, but it's just too hard to map everything out when you leave a room by going east but then to go back to where you came you need to go south.
    - stevekemp 4y ago
      Small world, thanks for your contributions! It wasn't very complicated, but I enjoyed putting it together and playing it with our child. For me the Hitchhikers Guide was something I'd been wanting to complete - having played it for the first time a little after the release -and I did get there in the end.

linuxhansl 4y ago

My foray into disk-based operation systems. Oh, sooo many years ago. A friend of mine had it, and I would ride my bike through country roads as a kid to play around with it.

zabzonk 4y ago

Lots of the source of CP/M came with the distribution, and it wasn't hard to dis-assemble specific bits you were interested in. Some CP/M software (I'm thinking of WordStar specifically here, but no doubt others) almost required you to write a keyboard and display handler in Z80/8080 machine code to get decent performance over the generic CP/M code - been there on Research Machines 380Zs.

jstanley 4y ago
Source has been available for years, it just hasn't been clear whether it was legal to redistribute it. Now it's clear :).
- bornfreddy 4y ago
  ...clearer (if at all). The proper license, whatever it is, is still missing. Sorry. :)

doctor_eval 4y ago

Why about MP/M. I loved having more than one user on a 8080.

dfawcus 4y ago
Source and binaries are on the site: http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html http://www.cpm.z80.de/binary.html#operating http://www.cpm.z80.de/binary.html#operating Search for MP
- doctor_eval 4y ago
  That is so cool. I'm not really a retro-computing guy and am unlikely to ever run this code, but it does bring back memories of bringing home an old unsold box from work, sitting on the garage floor, writing a program in unfamiliar 8080 mnemonics, and getting two terminals to chat to one another. OTOH it might be fun to get something working on a Z80 SOC. Or something like this https://hackaday.com/2017/01/02/retrocomputing-for-4-with-a-z80/ https://hackaday.com/2017/01/02/retrocomputing-for-4-with-a-... Has anyone ever trans-compiled Z80 assembly to a microcontroller? Is that even a thing?

kriro 4y ago

That is cool news because it's probably a nice starting point for osdev projects. At least more code to read :) I feel like the code was available before and I read parts of it but I may remember it wrong. Edit: Yes it was indeed "just" a license clarification. Link to the source: http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html

usr1106 4y ago

In high school in 1980 we had Commodore PETs. They had no tangible OS, just a BASIC interpreter in ROM. There was an easter egg that made it say Microsoft or wasn't it spelled MicroSoft? Either way a company nobody had ever heard of. CP/M had the aura of being something for real pros. Read some journal articles and it looked really complicated. But without suitable hardware I had never any chance to touch it. In 1983 I went to university where beginner courses happened on VAX/VMS and my definition of "pro" got shifted.

hdjjhhvvhga 4y ago
> In high school in 1980 we had Commodore PETs. They had no tangible OS, just a BASIC interpreter in ROM. Five years later the Commodore 128 appeared. It had the best of both worlds: could run all C64 games and CP/M. These were magic times.
- mongol 4y ago
  I always booted mine while pressing the Commodore key. Waste of money.
  - Cockbrand 4y ago
    With its separate number pad, it looked really grown-up and professional compared to the 64, though. The 128D even more so, with its desktop box, built-in floppy drive and separate keyboard.
    - mongol 4y ago
      Yes I had that one. It was the worst decision of my life. Had I waited 6 months or so, the Amiga 500 would have launched. I got stuck on dead hardware and got hooked off from computers for several years.
      - ansible 4y ago
        If it is any consolation, I got started on the Radio Shack Color Computer ecosystem, with the original version the the CoCo3. Back then, there was quite a bit of debate by the mid 1980's about the longevity of 8/16-bit processors like the 6809 and the 6502 / 6510 series. Addressing a maximum of 64KiB of memory back when 4KiB was expensive seemed fine. And due to cost, picking an 8-bit processor for a design in 1980 seemed sensible. But the ability to support up to 1MiB of RAM (eventually) on the 8086 series help insure the platform's longevity, in spite of the horrible segmented memory programming model. Companies like Motorola weren't terribly interested in backwards compatibility, preferring instead to design completely new instruction sets (like the 68K family) for their 32-bit platforms.

pavlov 4y ago

CP/M was the popular operating system that IBM wanted to license for their skunkworks Personal Computer project. But the founder of Digital Research, the company that developed CP/M, was more interested that day in going flying his plane than meeting with corporate men in navy suits. (This may be apocryphal.) IBM turned instead to their second choice, a small company that was supplying BASIC interpreters to many 8-bit micros. The company didn’t actually have a suitable disk operating system product, but the founder knew someone who did. He made a deal to license the source code for a fixed fee and no limitations on redistribution. And that’s how Bill Gates acquired MS-DOS for $50k.

Neil44 4y ago
CP/M was nice, it's a shame we got saddled with MS-DOS for decades.
- pjmlp 4y ago
  Having started my MS-DOS path with version 3.3, and used all MS-DOS versions, also the DR-DOS 5.0 and 6.0 versions, experienced CP/M on the Spectrum +3A, I fail to see how CP/M was better.
  - mongol 4y ago
    Which directory separator did it have?
    - Doctor_Fegg 4y ago
      CP/M didn't have sub-directories, though it did have 16 "user areas" on a disk.
      - II2II 4y ago
        MS-DOS did not have directories at first either. It was a feature in version 2.0, when hard drive support was added. Directories seem to have been a foreign concept among early home computer operating systems and I suspect its adoption was driven by the adoption of hard drives. For example, the Apple II did not gain directory support until ProDOS was introduced and the Macintosh only gained folders with the introduction of HFS. I don't recall directories existing for the Commodore 64 either.

timonoko 4y ago

I thought I had CP/M source code for Osborne-1. But no, I have only inch-thick listing of BIOS. And it did not matter, one always used direct Bios-calls for speed. CP/M was not actually needed for this implementation, it could boot on its own: http://timonoko.github.io/Nokolisp.htm http://timonoko.github.io/Nokolisp.htm

lkxijlewlf 4y ago

Slightly off topic: I recall as a youngin watching Gary Kildall on the Computer Chronicles. I was always fascinated by what people were doing with computers. I know it is nostalgia and there's infinitely more to learn about today than there was then, but I do miss that era of computing.

Cockbrand 4y ago

Of course, there's a CP/M emulator in the browser now, so you don't have to dig out your Z80/8080 computer: https://www.tramm.li/i8080/ https://www.tramm.li/i8080/

jhallenworld 4y ago

HP should open OS/8 and RT-11, the two big influences on CP/M. OS/8 is kind of remarkable, running on a system arguably less powerful than the first 8-bit home computers (I would say they are closer to PIC microcontrollers, but with more RAM): https://www.pdp8online.com/os/os8/index.shtml https://www.pdp8online.com/os/os8/index.shtml PDP-8 memory is heavily paged. There are 128 word pages- direct addresses can only reach within the current page, and literals (immediate data including addresses to other pages) have to be allocated out of this current page along with the instructions. Second, there are 4K-word fields. So you need to use far jumps and returns to access outside the current field. This is just like PIC microcontroller pages. OS/8 reserved only two pages for itself. Things like the command interpreter were swapped out to disk or DECTape. https://en.wikipedia.org/wiki/DECtape https://en.wikipedia.org/wiki/DECtape If the application needed device drivers, it got to choose which pages the drivers would occupy- meaning the device drivers had to be written as position independent code. Also I think each driver was limited to two pages..

Barrera 4y ago

> The discussion is not over yet, but we believe this statement is equivalent to the well-known BSD or MIT licenses. That's not now I'd interpret it. "Open Source" in my mind means that the software uses one of the OSI approved licenses. The quoted paragraph: > Let this paragraph represent a right to use, distribute, modify, enhance, and otherwise make available in a nonexclusive manner CP/M and its derivatives. This right comes from the company, DRDOS, Inc.'s purchase of Digital Research, the company and all assets, dating back to the mid-1990’s. DRDOS, Inc. and I, Bryan Sparks, President of DRDOS, Inc. as its representative, is the owner of CP/M and the successor in interest of Digital Research assets. is not even a license in the traditional sense. It defines nothing. Whatever rights it grants do not appear to be transferrable. Worst of all, it does not even mention source code. If the owners of the CP/M source code want to make it open source, what's so hard about attaching the actual MIT or BSD licenses to a source distribution and publishing it?

nibbleshifter 4y ago
> what's so hard about attaching the actual MIT or BSD licenses to a source distribution and publishing it? From experience in related things: lawyers.
zozbot234 4y ago
This is most likely why the post mentions that "discussion is not over yet". They seem to be quite optimistic that we might be getting a proper FLOSS release.
Cyberdog 4y ago
This sort of confusion could have been avoided if they had just said "the source code to this program is now free to distribute under the (MIT|BSD|GPL|etc) license" from the beginning. Nobody knew what exactly the intent of this novel "let this paragraph represent" approach was supposed to be, and now it just sounds like we have a slightly clearer idea. No need to get cutesy with something as important as your license terms, people.

Communitivity 4y ago

I remember CP/M with fondness. My father gave me an Osborne 1 for my first computer when I was 12 (41 years ago). It came with CBASIC2 as well as MBasic, and I managed to find a Lisp (I forget what flavor). To put the Osborne 1 in perspective, the stats: * 64kb memory (yes that's kilobytes) * 2 5 1/4 floppy disks * No hard disk * 5" monochrome green screen monitor * 4 MHz CPU * 37 watt power supply * weighed ~25 pounds

jfengel 4y ago
Plus an RS-232 for your modem and an IEEE 488 for your printer. That CPU lacked a multiply instruction, so you had to implement that yourself.
- veltas 4y ago
  The multiply instructions on later CPUs were implemented as microcode programs on the silicon, so sometimes it was faster to write your own or a specialised routine anyway.
jahnu 4y ago
Luxury! https://m.youtube.com/watch?v=ue7wM0QC5LE https://m.youtube.com/watch?v=ue7wM0QC5LE ;)
OnlyMortal 4y ago
4mhz CPU? Luxury super computer!
- varjag 4y ago
  3.5-4Mhz was standard for most Z80 based systems.
  - sedatk 4y ago
    Still, it didn't perform much better than a 1Mhz 6502 due to its design.

cosmiccatnap 4y ago

I'm sorry but it's not on MIT, GNU, or BSD so I would go so far as to say the title is clickbait...like can I take this code and try and get it to work on my x86 machine and then commit my changes under bsd? Probably not Can someone point me to a repo to look at it? I can't find a link and it doesn't show up on Google.

dboreham 4y ago
https://github.com/brouhaha/cpm22/blob/master/bdos.asm https://github.com/brouhaha/cpm22/blob/master/bdos.asm from http://www.cpm.z80.de/source.html http://www.cpm.z80.de/source.html

kazinator 4y ago

> This right comes from the company, DRDOS, Inc.'s purchase of Digital Research, the company and all assets, dating back to the mid-1990’s What the Wikipedia says, if you piece it together is that Bryan Sparks founded Caldera in the mid 1990's, which bought Digital Research. Around the time Caldera went defunct in 2002, Sparks started DeviceLogics which got renamed to DRDOS Inc. So that must have inherited the Caldera assets, including the Digital Research stuff.

smm11 4y ago

So IBM went crazy with CP/M, and Microsoft suffered. We'd now have CP/M 11, and DOS would be open-source now.

sbuk 4y ago
In all likelihood in that timeline DOS as we know it wouldn't have existed.
BirAdam 4y ago
I am not so certain that it would have made much difference. Microsoft would still have produced both BASIC and Windows, and we may have had the exact same evolution anyway. DigitalResearch's GEM was mired in legal red tape preventing from much evolution. Also, MSDOS is opensource now. https://computerhistory.org/blog/microsoft-ms-dos-early-source-code/?key=microsoft-ms-dos-early-source-code https://computerhistory.org/blog/microsoft-ms-dos-early-sour...

phendrenad2 4y ago

Always excellent when a piece of computing history has it's source made available. Even better when it's provided under a libre license, as this is! CP/M is a powerful example of what you can do without multitasking. The code is also a time capsule of development techniques and styles of the time.

marcodiego 4y ago

Good but 30-40 years too late.