6 ms·

CP/M Source Code

106 points by kristopolous 5y ago

cable2600 5y ago
It would be good to port this to Game consoles that use the Z80 CPU and hack together a keyboard and SDCard drive. Make them useful. MOst of the CP/M stuff is on the Internet and some is public domain by now.
- marcodiego 5y ago
  > MOst of the CP/M stuff is on the Internet and some is public domain by now. Sure? AFAIK something can only be considered public domain in one of the following conditions: - author explicitly uses public domain as a license, - 120 after publication, - 120 after registration, - 95 years after publication if it is corporate work or - 75 years after the death of the author; whatever comes first.
  - rtpg 5y ago
    Is copyright law dating uniform at this point? I wouldn't be surprised if it is... one thing I remember reading On The Internet a while back was a theory (from a lawyer I believe?) that stated that you can't just say you put something in the public domain, and have it then be in the public domain. Like, you can choose to explicitly grant rights of usage, but simply writing "I am putting this work in the public domain" doesn't actually do anything, and is functionally very close to being the same as "all rights reserved". I don't know if it's true though. I suppose we're fortunate that "nobody around to care" helps in practice for these kinds of conservation efforts that are victimless crimes at best.
    - foepys 5y ago
      This is correct. Public Domain is a concept unknown to the EU. You can never waive your copyright, only give permission to use to everybody. It's one of the reasons why SQLite sells licenses even though it's released as Public Domain. https://sqlite.org/purchase/license https://sqlite.org/purchase/license
      - colejohnson66 5y ago
        But why not CC0? That basically just grants an indefinite royalty-free license if public domain isn’t an option.
- laumars 5y ago
  Retro games consoles are already useful, as games consoles. People collect and play them still. If anything, modding them into an ultra low powered z80 PC would have less usefulness. As it happens, there already are a number of z80 micro computers out there. Most of which will already have a CP/M port.
  - opminion 5y ago
    Indeed, Amstrad CPC 6128, a home computer which booted to Basic, just like C64 and ZX Spectrum, came with CP/M too.
    - laumars 5y ago
      Not just the 6128, the earlier and lower powered 464 did too.
- CodeWriter23 5y ago
  CP/M has a BIOS interface for such customization. I’ve written more than several. Knock yourself out. NOTE: Digital Research used the term BIOS to describe its device driver interface long before IBM appropriated it for the IBM PC. It’s definitely not the same thing.
actually_a_dog 5y ago
This isn't just CP/M by far. I suggest the title be changed to "Digital Research Source Code", since that's what's inside the <title> tags.
- throwaway81523 5y ago
  It is also pretty ancient, going back to 2002 or earlier for everything except the Basic/E program. Post title should reflect this. The source code I'd really like to see is Turbo Pascal 1.x or its CP/M predecessor, but I don't think that was ever released.
  - pjmlp 5y ago
    Here you go, http://pascal.hansotten.com/delphi/turbo-pascal-on-cpm-msx-dos-and-ms-dos/ http://pascal.hansotten.com/delphi/turbo-pascal-on-cpm-msx-d...
    - throwaway81523 5y ago
      Maybe I missed something but I see some Turbo Pascal related tools there, and some binaries of TP, and some code written in TP, but not anything that looks like the source code to TP itself. I don't think that was ever released. A well-commented disassembly would be interesting and could possibly be created by devotees, of course. I never actually used TP myself but it sounded great. These two articles made me interested in it: * https://prog21.dadgum.com/116.html https://prog21.dadgum.com/116.html * https://prog21.dadgum.com/47.html https://prog21.dadgum.com/47.html
      - elvis70 5y ago
        Here is a disassembly of TP3 for CP/M-Z80, which seems well commented (I've just checked the compiler): https://web.archive.org/web/20131119042246/http://www.cirsovius.de/CPM/Projekte/Disassembler/TURBO-en.html https://web.archive.org/web/20131119042246/http://www.cirsov... And here is a disassembly for the versions 1,2,3 apparently: https://www.memotech.franken.de/CPM80/ https://www.memotech.franken.de/CPM80/
ngcc_hk 5y ago
Surprise by comments; 2002 is very new to me. Use it around 1970s/80s latest. And turbo pascal (I am still playing their turbo bridge) is of 1980s.
- hedgewitch 5y ago
  They just mean that it wasn't posted very recently and want it reflected in the title that this is not a new discovery.
- kristopolous 5y ago
  The original maintainer died in 2001. Maybe they mean new as in a section that was added by someone else. If that's the case here, it's totally acceptable to always have it be called new
pjmlp 5y ago
Look a systems programming language for 8 bit CPUs with safe strings and arrays. /s
- ratboy666 5y ago
  Um... PL/M is not safe, and does not have "safe strings and arrays". It doesn't have strings... It has bytes and addresses. I hope /s means "sarcastic".
  - timbit42 5y ago
    What else would /s mean?
  - kierenj 5y ago
    That is indeed what /s means
  - pjmlp 5y ago
    I was being sarcastic, but not in relation to PL/M. It has subscripted variables with LENGTH() to check its size (aka arrays), and an array of bytes is a string. You can even create structures of subscripted variables. PL/M manuals have a couple of examples with string utility functions by the way.
rbanffy 5y ago
Digital Research was the Microsoft we needed.
- pjmlp 5y ago
  Blame it on how the whole deal with IBM ended up.
  - rbanffy 5y ago
    Wasn’t that because Bill’s mom had a friend on the IBM board?
    - ebcode 5y ago
      ITPro has a recent write-up: https://www.itpro.com/hardware/361331/the-true-story-behind-the-ibm-personal-computer https://www.itpro.com/hardware/361331/the-true-story-behind-...
    - pjmlp 5y ago
      That is one possible rummor I guess. https://en.wikipedia.org/wiki/Gary_Kildall#IBM_dealings https://en.wikipedia.org/wiki/Gary_Kildall#IBM_dealings https://news.ycombinator.com/item?id=9667831 https://news.ycombinator.com/item?id=9667831
deleted 5y ago
[deleted]
mistrial9 5y ago
I programmed in CP/M as a teen, and it was a different world then.. Byte Magazine was the way to find out about products and development; machines were connected to each other with a serial cable; a modem was used to send bits over a phone line. Its annoying to see the comment about 'string safety' .. how about you do what you want with your own computer, which is not logged, watched, billed or updated without your consent. This code relates to a machine that you, as an individual, own. An individual person can do what they want with it, without a spy-OS within the CPU itself, for example. Its clear (to me) that there has to be a serious fork in CPU development, which will need OS software, maybe back to Z80'ish 8 bits even.. This setup wont display JPG at multiple images per second rate from some centralized media servers, but you know, maybe that is a feature. "free" as in "freedom"
hungryforcodes 5y ago
Actually the most recent comment is dated 02/07/2020 -- which I think is pretty good for an operating system that is 40 years old about.

106 points by kristopolous 5y ago

It would be good to port this to Game consoles that use the Z80 CPU and hack together a keyboard and SDCard drive. Make them useful. MOst of the CP/M stuff is on the Internet and some is public domain by now.

marcodiego 5y ago
> MOst of the CP/M stuff is on the Internet and some is public domain by now. Sure? AFAIK something can only be considered public domain in one of the following conditions: - author explicitly uses public domain as a license, - 120 after publication, - 120 after registration, - 95 years after publication if it is corporate work or - 75 years after the death of the author; whatever comes first.
- rtpg 5y ago
  Is copyright law dating uniform at this point? I wouldn't be surprised if it is... one thing I remember reading On The Internet a while back was a theory (from a lawyer I believe?) that stated that you can't just say you put something in the public domain, and have it then be in the public domain. Like, you can choose to explicitly grant rights of usage, but simply writing "I am putting this work in the public domain" doesn't actually do anything, and is functionally very close to being the same as "all rights reserved". I don't know if it's true though. I suppose we're fortunate that "nobody around to care" helps in practice for these kinds of conservation efforts that are victimless crimes at best.
  - foepys 5y ago
    This is correct. Public Domain is a concept unknown to the EU. You can never waive your copyright, only give permission to use to everybody. It's one of the reasons why SQLite sells licenses even though it's released as Public Domain. https://sqlite.org/purchase/license https://sqlite.org/purchase/license
    - colejohnson66 5y ago
      But why not CC0? That basically just grants an indefinite royalty-free license if public domain isn’t an option.
laumars 5y ago
Retro games consoles are already useful, as games consoles. People collect and play them still. If anything, modding them into an ultra low powered z80 PC would have less usefulness. As it happens, there already are a number of z80 micro computers out there. Most of which will already have a CP/M port.
- opminion 5y ago
  Indeed, Amstrad CPC 6128, a home computer which booted to Basic, just like C64 and ZX Spectrum, came with CP/M too.
  - laumars 5y ago
    Not just the 6128, the earlier and lower powered 464 did too.
CodeWriter23 5y ago
CP/M has a BIOS interface for such customization. I’ve written more than several. Knock yourself out. NOTE: Digital Research used the term BIOS to describe its device driver interface long before IBM appropriated it for the IBM PC. It’s definitely not the same thing.

actually_a_dog 5y ago

This isn't just CP/M by far. I suggest the title be changed to "Digital Research Source Code", since that's what's inside the <title> tags.

throwaway81523 5y ago
It is also pretty ancient, going back to 2002 or earlier for everything except the Basic/E program. Post title should reflect this. The source code I'd really like to see is Turbo Pascal 1.x or its CP/M predecessor, but I don't think that was ever released.
- pjmlp 5y ago
  Here you go, http://pascal.hansotten.com/delphi/turbo-pascal-on-cpm-msx-dos-and-ms-dos/ http://pascal.hansotten.com/delphi/turbo-pascal-on-cpm-msx-d...
  - throwaway81523 5y ago
    Maybe I missed something but I see some Turbo Pascal related tools there, and some binaries of TP, and some code written in TP, but not anything that looks like the source code to TP itself. I don't think that was ever released. A well-commented disassembly would be interesting and could possibly be created by devotees, of course. I never actually used TP myself but it sounded great. These two articles made me interested in it: * https://prog21.dadgum.com/116.html https://prog21.dadgum.com/116.html * https://prog21.dadgum.com/47.html https://prog21.dadgum.com/47.html
    - elvis70 5y ago
      Here is a disassembly of TP3 for CP/M-Z80, which seems well commented (I've just checked the compiler): https://web.archive.org/web/20131119042246/http://www.cirsovius.de/CPM/Projekte/Disassembler/TURBO-en.html https://web.archive.org/web/20131119042246/http://www.cirsov... And here is a disassembly for the versions 1,2,3 apparently: https://www.memotech.franken.de/CPM80/ https://www.memotech.franken.de/CPM80/

ngcc_hk 5y ago

Surprise by comments; 2002 is very new to me. Use it around 1970s/80s latest. And turbo pascal (I am still playing their turbo bridge) is of 1980s.

hedgewitch 5y ago
They just mean that it wasn't posted very recently and want it reflected in the title that this is not a new discovery.
kristopolous 5y ago
The original maintainer died in 2001. Maybe they mean new as in a section that was added by someone else. If that's the case here, it's totally acceptable to always have it be called new

pjmlp 5y ago

Look a systems programming language for 8 bit CPUs with safe strings and arrays. /s

ratboy666 5y ago
Um... PL/M is not safe, and does not have "safe strings and arrays". It doesn't have strings... It has bytes and addresses. I hope /s means "sarcastic".
- timbit42 5y ago
  What else would /s mean?
- kierenj 5y ago
  That is indeed what /s means
- pjmlp 5y ago
  I was being sarcastic, but not in relation to PL/M. It has subscripted variables with LENGTH() to check its size (aka arrays), and an array of bytes is a string. You can even create structures of subscripted variables. PL/M manuals have a couple of examples with string utility functions by the way.

rbanffy 5y ago

Digital Research was the Microsoft we needed.

pjmlp 5y ago
Blame it on how the whole deal with IBM ended up.
- rbanffy 5y ago
  Wasn’t that because Bill’s mom had a friend on the IBM board?
  - ebcode 5y ago
    ITPro has a recent write-up: https://www.itpro.com/hardware/361331/the-true-story-behind-the-ibm-personal-computer https://www.itpro.com/hardware/361331/the-true-story-behind-...
  - pjmlp 5y ago
    That is one possible rummor I guess. https://en.wikipedia.org/wiki/Gary_Kildall#IBM_dealings https://en.wikipedia.org/wiki/Gary_Kildall#IBM_dealings https://news.ycombinator.com/item?id=9667831 https://news.ycombinator.com/item?id=9667831

deleted 5y ago

[deleted]

mistrial9 5y ago

I programmed in CP/M as a teen, and it was a different world then.. Byte Magazine was the way to find out about products and development; machines were connected to each other with a serial cable; a modem was used to send bits over a phone line. Its annoying to see the comment about 'string safety' .. how about you do what you want with your own computer, which is not logged, watched, billed or updated without your consent. This code relates to a machine that you, as an individual, own. An individual person can do what they want with it, without a spy-OS within the CPU itself, for example. Its clear (to me) that there has to be a serious fork in CPU development, which will need OS software, maybe back to Z80'ish 8 bits even.. This setup wont display JPG at multiple images per second rate from some centralized media servers, but you know, maybe that is a feature. "free" as in "freedom"

hungryforcodes 5y ago

Actually the most recent comment is dated 02/07/2020 -- which I think is pretty good for an operating system that is 40 years old about.