10 ms·

Why the Apple II ProDOS 2.4 Release Is the OS News of the Year

298 points by bootload 10y ago

watermoose 10y ago
Thank you John Brooks!! You are the best!! Warning: this is going to get mushy... While my first computer was the TRS-80 COCO I, I spent more time coding on my second computer, the Apple IIe, coming home each afternoon after school to just program and play games constantly. I owe my current occupation to that, and my family and friends that benefit from my salary I all owe to those two computers. I love the Apple II line along with the TRS-80 COCO line and my heart is full that there are those that continue to develop for them.
deleted 10y ago
[deleted]
ultramancool 10y ago
Sounds similar to the China Dos Union MS-DOS "7.1" which used the DOS from Windows 98 and included FAT32 support, long file names and a CD-based installer. https://winworldpc.com/product/ms-dos/7x https://winworldpc.com/product/ms-dos/7x
- bdowling 10y ago
  This is most likely derived from the Apple DOS source code that was released a while back, with new features added. This makes it quite different from the MS-DOS you describe, which is just a repackaging of components from Windows 98. http://www.computerhistory.org/atchm/apple-ii-dos-source-code/ http://www.computerhistory.org/atchm/apple-ii-dos-source-cod...
  - enf 10y ago
    There is very little code in common between Apple DOS and Apple ProDOS. A disassembly of ProDOS is much more likely.
- userbinator 10y ago
  I remember coming across that many years ago, as far as I remember it was a rather interesting group of Chinese DOS-using hobbyists. They also came up with a "Windows 3.2" that fit on a floppy and was also based on the 7.1, creating possibly the only 3.x version of Windows with long filename support. The latter was released under the name "PMWIN3.ZIP" and apparently can only be found in the Internet archives now: http://web.archive.org/web/20070128175800/http://www.cn-dos.net/msdos71/pmwin3.zip http://web.archive.org/web/20070128175800/http://www.cn-dos.... (The rest of cn-dos.net is also worth checking out if you read Chinese or find Google Translate to be sufficient; this is an example of one of the forgotten-yet-very-interesting parts of the Internet.)
  - stuaxo 10y ago
    Interesting, do the open-file dialogues and winfile support LFNs in this ? (@ work and can't look right now).
    - userbinator 10y ago
      Yes: http://reboot.pro/uploads/monthly_04_2008/post-5-1208637282.jpg http://reboot.pro/uploads/monthly_04_2008/post-5-1208637282.... I'm not sure how they did it though, maybe when I have the time I'll look into it since this is a very unusual software.
      - pgeorgi 10y ago
        probably copied the NT3.5 file manager and hacked it to work with win32s? that's probably easier than modifying the win3.11 binaries to hold file name buffers than what's needed for the 8.3 scheme. (or maybe they binaries are actually pretty similar, so all it needed was a slight API change for file name lookup)
- slipstream- 10y ago
  7.1 wasn't just a version number that China DOS Union made up but is the actual version number of win98's (and 95 OSR 2's) DOS.
endgame 10y ago
Old apple stuff isn't my thing but I applaud any efforts to preserve our history. Jason makes a number of good points about the sorry state of modern OSes in his article, and it's worth a read for that alone.
- userbinator 10y ago
  Along the same lines there's an "unofficial service pack" for Windows 98SE which fixes a lot of little issues and actually allows running some substantially newer applications on the 18-year-old OS. I wouldn't be surprised if 2K/XP get the same treatment, and in fact I know it's already happening. It's sometimes amazing what the community can come up with.
  - RachelF 10y ago
    I wish one could force vendors to open source operating systems they no longer support.
    - chongli 10y ago
      Oh yes! Then we could get the source to Mac OS 9 and bring it into the modern era! Spatial metaphor forever!
      - firebones 10y ago
        Imagine a fork of various Apple OS's that took skeuomorphic interfaces to their logical conclusion! We need a name for this: an open set of parallel computing universes. Maybe OpenCandide: The Best of All Possible Worlds. (Ironic misinterpretation of the phrase intentional.)
        chongli 10y ago
        I'm not sure if you were implying otherwise or not, but: spatial metaphor file managers are not skeuomorphic. Skeuomorphism strictly encompasses non-functional interface elements, such as faux-leather stitching on Apple's old address book application. The spatial metaphor Finder in OS 9 was 100% functional. The way it remembered all of the details (size, layout, position, display mode) of each window and the way each window had an unbreakable 1 to 1 connection to a folder made it a joy to use. It allowed the user to identify what window belonged to a folder at a glance and to be able to set up a whole workspace arrangement and have it be remembered automatically by the Finder.
slyrus 10y ago
Wow. This brings back memories of my first job at Apple working on the IIe emulation board for the Mac LC.
- rocky1138 10y ago
  Write a blog post!
- mrpippy 10y ago
  Would love to hear more also! Did you have any involvement with 'Gus', the IIgs emulator written (but never publicly released) by Apple?
bronson 10y ago
FTA, on why this is important: Next is that this is an operating system upgrade free of commercial and marketing constraints and drives. Compared with, say, an iOS upgrade that trumpets the addition of a search function or blares out a proud announcement that they broke maps because Google kissed another boy at recess. Or Windows 10, the 1968 Democratic Convention Riot of Operating Systems, which was designed from the ground up to be compatible with a variety of mobile/tablet products that are on the way out, and which were shoved down the throats of current users with a cajoling, insulting methodology with misleading opt-out routes and freakier and freakier fake-countdowns. So true. :/
- nevster 10y ago
  Heh, for anyone momentarily confused as I was, FTA stands for 'from the article' and is not a comment by the Apple IIGS Free Tools Association. :)
  - hollander 10y ago
    Ha! I thought the F stood for something else. I guess in 1993 the world was a different place!
    - rangibaby 10y ago
      TFA? The fine article? ;-)
- stephenr 10y ago
  > blares out a proud announcement that they broke maps because Google kissed another boy at recess Sure, if by "broke", you mean "built a privacy-respecting competitor based on a well-trusted open map technology called OpenStreetMap", and if by "kissed another boy", you mean "withheld turn-by-turn navigation because Apple wouldn't let Google whore out end-users private information as part of the process"..,
  - marmshallow 10y ago
SwellJoe 10y ago
I have so much admiration for the people who keep old platforms alive. I tinker with a Commodore 64 (a real one) now and then, and I'm just blown away by the community that still exists around it. People still write new software, build new hardware (I have a MSSIAH synth/MIDI interface cartridge and it's a blast to play with), make new demos and intros, discover new graphics modes and sound techniques, etc. The landscape is pretty well mapped out, but people still manage to find new ways to look at it every now and then. I've always wanted an Apple IIgs, because it had a built-in FM synth that was really powerful for the time (I have a fascination with electronic music and equipment from that era, which is why I have the C64 and MSSIAH, as well as a Gameboy with LSDJ). Maybe now is a good time to start looking around for one. This is a fantastic story...I want to play with it, just because.
- nsxwolf 10y ago
  The Apple IIgs is still cheap to acquire and fun to own, so I recommend picking one up.
  - SwellJoe 10y ago
    I'm currently living in an RV, so my space is very limited. I'd have to get rid of something in order to make room for it! If I buy some land and put a tiny house and studio on it, I'll definitely pick one up. There's a bunch of old hardware I'd love to have, but it's definitely a hobby for someone with some extra space (and also extra time, which I also don't have a lot of lately).
- rsync 10y ago
  "I tinker with a Commodore 64 (a real one) now and then, and I'm just blown away by the community that still exists around it." I am curious - is there an analog in the c64 world to this new ProDOS 2.4 release ? That is to say, have enthusiasts reworked and re-released the built-in c64 firmware or otherwise reworked the OS ?
  - vidarh 10y ago
    The C64 firmware was mapped out in detail when the C64 was in its heyday - you had books published with full commented disassembly. And because the C64 had the full 64K RAM, but used bank switching to overlay the ROMs, there were tons of "OS upgrades" that simply mirrored the ROM into the underlying RAM, made various modifications, and bank switched the ROMs out. So yes there was, but most of hit happened 20-30 years ago already. There were tons of commercial expansions based on this method, such as Simons' BASIC, and the far more ambitious Lightning/White Lightning, which I believe started as a Forth system, and was ported to other platforms too, but also came in a BASIC version. On the C64 - I don't know how different e.g. the Spectrum version was - it allowed multitasking up to 3 or 4 BASIC programs + sprite animation, and offered a lot of extensions for graphics and sound. Many of these extensions led to equivalent ones written by enthusiasts or published with source in various books. E.g. a number of the books available here [1] have such extensions in them. Later you got things like GEOS that provided a fully windowed user interface with word processor, spreadsheet, ide's etc. GEOS only really worked decently if you got a hard drive or RAM expansion, though, both of which were rare. The most common "OS rework" on the C64, though, were freezer cartridges. So named because they had a "freeze" button that would jump into the code on the cartridge without touching anything in main memory, and let you mess around with it, and then restore the original state or dump everything to disk. Which made things like copying games fairly trivial most of the time, but also allowed for things like semi-automated "trainers" (you'd freeze, enable an option, go back into a game, lose a life, freeze again, and the cartridge would scan memory looking for memory locations that were likely locations of life counters, and scan for code that modified them). There were a bunch of them, with Action Replay and The Final Cartridge being the most popular brands. Action Replay VI being the last one or the C64, but there are Action Replay cartridges and even PC expansion cards for a bunch of other platforms. The Final Cartridge ironically was also released in multiple version, with The Final Cartridge III also including a windowed user interface (which did not end up getting used much, as only very rudimentary software was included and hardly any third party software supported it). In terms of contemporary stuff, there's the C64 version of Contiki [2] at least, and I'm sure there's more. [1] http://www.bombjack.org/commodore/books.htm http://www.bombjack.org/commodore/books.htm [2] https://www.c64-wiki.com/index.php/Contiki https://www.c64-wiki.com/index.php/Contiki
stinos 10y ago
Interesting read, but no mention at all of what this thing is, or will be, used for. Anyone?
- KMag 10y ago
  My memory of 30 years ago is a bit rusty, but I don't recall an easy way to format an Apple II disk without putting either Apple DOS or Apple ProDOS on the disk. This version is smaller, more widely compatible, and adds several third-party add-on features to ProDOS. So, it's useful any time you'd format a disk in your Apple II emulator. Now you get more utilities, and you disk works on a wider variety of hardware.
partycoder 10y ago
Another heroic effort was the posthumous release of Star Fox II. A community took the Japanese alpha of Star Fox II, patched all the bugs, made it fully playable, and translated it into English. I finished it and I can tell you it was better than Star Fox 64.
exlurker 10y ago
I love this kind of stuff! Related is the reverse engineered GEOS (C64) available at github: https://github.com/mist64/geos https://github.com/mist64/geos The maintainers are gearing up to support more platforms, CPUs, repair and extend!
micro_softy 10y ago
Here's an interesting retweet from ProDOS's author last month. @JBrooksBSI [59]Aug 17 Was MS-DOS copied from CP/M? [60]embedded.com/electronics-bl... 60. https://t.co/mOR5mLBHwC http://www.embedded.com/electronics-blogs/say-what-/4442498/Was-DOS-copied-from-CPM- http://www.embedded.com/electronics-blogs/say-what-/4442498/...
- 13of40 10y ago
  "My conclusion is that DOS source code was not copied from CP/M source code." "The commands were not copied; they were simple, descriptive terms that were common to other operating system such as VMS and Apple DOS." "The DOS system calls were definitely copied from the CP/M system calls. Given the quantity of identical numbers representing identical functions, it is clear that Tim Paterson referenced the CP/M manual when writing DOS." The last bit is alluded to in page D-7 of the DOS 1.0 user manual[1], which says "There is an additional mechanism for pre-existing programs that were written with different calling conventions. The function number is placed in the CL register...and an intrasegment call is made to location 5 in the current code segment." That's because in CP/M, "...access to the FDOS functions is accomplished by passing a function number and information address through the primary point at location BOOT+0005H" [2]. [1] https://archive.org/details/bitsavers_ibmpcdos61_7006095 https://archive.org/details/bitsavers_ibmpcdos61_7006095 [2] http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch5.htm#Section_5.2 http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch5.htm#Sect... So, yes, the DOS function calls were designed with CP/M backwards compatibility in mind, and it says so right in the manual. Kind of.
cpeterso 10y ago
So how does one fix bugs in ProDOS 2.0.3? I assume John Brooks does not have the ProDOS source code. Is he patching the old binaries?
- teach 10y ago
  I'm going to go out on a limb and say that ProDOS was originally written directly in assembly and not compiled from a higher-level language. Disassembling is pretty trivial compared to de-compiling.
StillBored 10y ago
Hmm, Still looks like it has the 32M (IIRC) partition limit. There are GSOS drivers to work around this, but not for generic 8-bit prodos (AFAIK). Frankly, the II line was always slow moving (the IIE was sold commercially longer than any other computer without any significant upgrades). Which is why was such a great learning computer, there were only a couple models, very well documented, and hacked on to uncover every tiny little trick/edge case. Now days, I look at 6502 assembly and wonder how I managed to get anything done with such a restrictive stack/etc.

298 points by bootload 10y ago

Thank you John Brooks!! You are the best!! Warning: this is going to get mushy... While my first computer was the TRS-80 COCO I, I spent more time coding on my second computer, the Apple IIe, coming home each afternoon after school to just program and play games constantly. I owe my current occupation to that, and my family and friends that benefit from my salary I all owe to those two computers. I love the Apple II line along with the TRS-80 COCO line and my heart is full that there are those that continue to develop for them.

deleted 10y ago

[deleted]

ultramancool 10y ago

Sounds similar to the China Dos Union MS-DOS "7.1" which used the DOS from Windows 98 and included FAT32 support, long file names and a CD-based installer. https://winworldpc.com/product/ms-dos/7x https://winworldpc.com/product/ms-dos/7x

bdowling 10y ago
This is most likely derived from the Apple DOS source code that was released a while back, with new features added. This makes it quite different from the MS-DOS you describe, which is just a repackaging of components from Windows 98. http://www.computerhistory.org/atchm/apple-ii-dos-source-code/ http://www.computerhistory.org/atchm/apple-ii-dos-source-cod...
- enf 10y ago
  There is very little code in common between Apple DOS and Apple ProDOS. A disassembly of ProDOS is much more likely.
userbinator 10y ago
I remember coming across that many years ago, as far as I remember it was a rather interesting group of Chinese DOS-using hobbyists. They also came up with a "Windows 3.2" that fit on a floppy and was also based on the 7.1, creating possibly the only 3.x version of Windows with long filename support. The latter was released under the name "PMWIN3.ZIP" and apparently can only be found in the Internet archives now: http://web.archive.org/web/20070128175800/http://www.cn-dos.net/msdos71/pmwin3.zip http://web.archive.org/web/20070128175800/http://www.cn-dos.... (The rest of cn-dos.net is also worth checking out if you read Chinese or find Google Translate to be sufficient; this is an example of one of the forgotten-yet-very-interesting parts of the Internet.)
- stuaxo 10y ago
  Interesting, do the open-file dialogues and winfile support LFNs in this ? (@ work and can't look right now).
  - userbinator 10y ago
    Yes: http://reboot.pro/uploads/monthly_04_2008/post-5-1208637282.jpg http://reboot.pro/uploads/monthly_04_2008/post-5-1208637282.... I'm not sure how they did it though, maybe when I have the time I'll look into it since this is a very unusual software.
    - pgeorgi 10y ago
      probably copied the NT3.5 file manager and hacked it to work with win32s? that's probably easier than modifying the win3.11 binaries to hold file name buffers than what's needed for the 8.3 scheme. (or maybe they binaries are actually pretty similar, so all it needed was a slight API change for file name lookup)
slipstream- 10y ago
7.1 wasn't just a version number that China DOS Union made up but is the actual version number of win98's (and 95 OSR 2's) DOS.

endgame 10y ago

Old apple stuff isn't my thing but I applaud any efforts to preserve our history. Jason makes a number of good points about the sorry state of modern OSes in his article, and it's worth a read for that alone.

userbinator 10y ago
Along the same lines there's an "unofficial service pack" for Windows 98SE which fixes a lot of little issues and actually allows running some substantially newer applications on the 18-year-old OS. I wouldn't be surprised if 2K/XP get the same treatment, and in fact I know it's already happening. It's sometimes amazing what the community can come up with.
- RachelF 10y ago
  I wish one could force vendors to open source operating systems they no longer support.
  - chongli 10y ago
    Oh yes! Then we could get the source to Mac OS 9 and bring it into the modern era! Spatial metaphor forever!
    - firebones 10y ago
      Imagine a fork of various Apple OS's that took skeuomorphic interfaces to their logical conclusion! We need a name for this: an open set of parallel computing universes. Maybe OpenCandide: The Best of All Possible Worlds. (Ironic misinterpretation of the phrase intentional.)
      - chongli 10y ago
        I'm not sure if you were implying otherwise or not, but: spatial metaphor file managers are not skeuomorphic. Skeuomorphism strictly encompasses non-functional interface elements, such as faux-leather stitching on Apple's old address book application. The spatial metaphor Finder in OS 9 was 100% functional. The way it remembered all of the details (size, layout, position, display mode) of each window and the way each window had an unbreakable 1 to 1 connection to a folder made it a joy to use. It allowed the user to identify what window belonged to a folder at a glance and to be able to set up a whole workspace arrangement and have it be remembered automatically by the Finder.

slyrus 10y ago

Wow. This brings back memories of my first job at Apple working on the IIe emulation board for the Mac LC.

rocky1138 10y ago
Write a blog post!
mrpippy 10y ago
Would love to hear more also! Did you have any involvement with 'Gus', the IIgs emulator written (but never publicly released) by Apple?

bronson 10y ago

FTA, on why this is important: Next is that this is an operating system upgrade free of commercial and marketing constraints and drives. Compared with, say, an iOS upgrade that trumpets the addition of a search function or blares out a proud announcement that they broke maps because Google kissed another boy at recess. Or Windows 10, the 1968 Democratic Convention Riot of Operating Systems, which was designed from the ground up to be compatible with a variety of mobile/tablet products that are on the way out, and which were shoved down the throats of current users with a cajoling, insulting methodology with misleading opt-out routes and freakier and freakier fake-countdowns. So true. :/

nevster 10y ago
Heh, for anyone momentarily confused as I was, FTA stands for 'from the article' and is not a comment by the Apple IIGS Free Tools Association. :)
- hollander 10y ago
  Ha! I thought the F stood for something else. I guess in 1993 the world was a different place!
  - rangibaby 10y ago
    TFA? The fine article? ;-)
stephenr 10y ago
> blares out a proud announcement that they broke maps because Google kissed another boy at recess Sure, if by "broke", you mean "built a privacy-respecting competitor based on a well-trusted open map technology called OpenStreetMap", and if by "kissed another boy", you mean "withheld turn-by-turn navigation because Apple wouldn't let Google whore out end-users private information as part of the process"..,
- marmshallow 10y ago

SwellJoe 10y ago

I have so much admiration for the people who keep old platforms alive. I tinker with a Commodore 64 (a real one) now and then, and I'm just blown away by the community that still exists around it. People still write new software, build new hardware (I have a MSSIAH synth/MIDI interface cartridge and it's a blast to play with), make new demos and intros, discover new graphics modes and sound techniques, etc. The landscape is pretty well mapped out, but people still manage to find new ways to look at it every now and then. I've always wanted an Apple IIgs, because it had a built-in FM synth that was really powerful for the time (I have a fascination with electronic music and equipment from that era, which is why I have the C64 and MSSIAH, as well as a Gameboy with LSDJ). Maybe now is a good time to start looking around for one. This is a fantastic story...I want to play with it, just because.

nsxwolf 10y ago
The Apple IIgs is still cheap to acquire and fun to own, so I recommend picking one up.
- SwellJoe 10y ago
  I'm currently living in an RV, so my space is very limited. I'd have to get rid of something in order to make room for it! If I buy some land and put a tiny house and studio on it, I'll definitely pick one up. There's a bunch of old hardware I'd love to have, but it's definitely a hobby for someone with some extra space (and also extra time, which I also don't have a lot of lately).
rsync 10y ago
"I tinker with a Commodore 64 (a real one) now and then, and I'm just blown away by the community that still exists around it." I am curious - is there an analog in the c64 world to this new ProDOS 2.4 release ? That is to say, have enthusiasts reworked and re-released the built-in c64 firmware or otherwise reworked the OS ?
- vidarh 10y ago
  The C64 firmware was mapped out in detail when the C64 was in its heyday - you had books published with full commented disassembly. And because the C64 had the full 64K RAM, but used bank switching to overlay the ROMs, there were tons of "OS upgrades" that simply mirrored the ROM into the underlying RAM, made various modifications, and bank switched the ROMs out. So yes there was, but most of hit happened 20-30 years ago already. There were tons of commercial expansions based on this method, such as Simons' BASIC, and the far more ambitious Lightning/White Lightning, which I believe started as a Forth system, and was ported to other platforms too, but also came in a BASIC version. On the C64 - I don't know how different e.g. the Spectrum version was - it allowed multitasking up to 3 or 4 BASIC programs + sprite animation, and offered a lot of extensions for graphics and sound. Many of these extensions led to equivalent ones written by enthusiasts or published with source in various books. E.g. a number of the books available here [1] have such extensions in them. Later you got things like GEOS that provided a fully windowed user interface with word processor, spreadsheet, ide's etc. GEOS only really worked decently if you got a hard drive or RAM expansion, though, both of which were rare. The most common "OS rework" on the C64, though, were freezer cartridges. So named because they had a "freeze" button that would jump into the code on the cartridge without touching anything in main memory, and let you mess around with it, and then restore the original state or dump everything to disk. Which made things like copying games fairly trivial most of the time, but also allowed for things like semi-automated "trainers" (you'd freeze, enable an option, go back into a game, lose a life, freeze again, and the cartridge would scan memory looking for memory locations that were likely locations of life counters, and scan for code that modified them). There were a bunch of them, with Action Replay and The Final Cartridge being the most popular brands. Action Replay VI being the last one or the C64, but there are Action Replay cartridges and even PC expansion cards for a bunch of other platforms. The Final Cartridge ironically was also released in multiple version, with The Final Cartridge III also including a windowed user interface (which did not end up getting used much, as only very rudimentary software was included and hardly any third party software supported it). In terms of contemporary stuff, there's the C64 version of Contiki [2] at least, and I'm sure there's more. [1] http://www.bombjack.org/commodore/books.htm http://www.bombjack.org/commodore/books.htm [2] https://www.c64-wiki.com/index.php/Contiki https://www.c64-wiki.com/index.php/Contiki

stinos 10y ago

Interesting read, but no mention at all of what this thing is, or will be, used for. Anyone?

KMag 10y ago
My memory of 30 years ago is a bit rusty, but I don't recall an easy way to format an Apple II disk without putting either Apple DOS or Apple ProDOS on the disk. This version is smaller, more widely compatible, and adds several third-party add-on features to ProDOS. So, it's useful any time you'd format a disk in your Apple II emulator. Now you get more utilities, and you disk works on a wider variety of hardware.

partycoder 10y ago

Another heroic effort was the posthumous release of Star Fox II. A community took the Japanese alpha of Star Fox II, patched all the bugs, made it fully playable, and translated it into English. I finished it and I can tell you it was better than Star Fox 64.

exlurker 10y ago

I love this kind of stuff! Related is the reverse engineered GEOS (C64) available at github: https://github.com/mist64/geos https://github.com/mist64/geos The maintainers are gearing up to support more platforms, CPUs, repair and extend!

micro_softy 10y ago

Here's an interesting retweet from ProDOS's author last month. @JBrooksBSI [59]Aug 17 Was MS-DOS copied from CP/M? [60]embedded.com/electronics-bl... 60. https://t.co/mOR5mLBHwC http://www.embedded.com/electronics-blogs/say-what-/4442498/Was-DOS-copied-from-CPM- http://www.embedded.com/electronics-blogs/say-what-/4442498/...

13of40 10y ago
"My conclusion is that DOS source code was not copied from CP/M source code." "The commands were not copied; they were simple, descriptive terms that were common to other operating system such as VMS and Apple DOS." "The DOS system calls were definitely copied from the CP/M system calls. Given the quantity of identical numbers representing identical functions, it is clear that Tim Paterson referenced the CP/M manual when writing DOS." The last bit is alluded to in page D-7 of the DOS 1.0 user manual[1], which says "There is an additional mechanism for pre-existing programs that were written with different calling conventions. The function number is placed in the CL register...and an intrasegment call is made to location 5 in the current code segment." That's because in CP/M, "...access to the FDOS functions is accomplished by passing a function number and information address through the primary point at location BOOT+0005H" [2]. [1] https://archive.org/details/bitsavers_ibmpcdos61_7006095 https://archive.org/details/bitsavers_ibmpcdos61_7006095 [2] http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch5.htm#Section_5.2 http://www.gaby.de/cpm/manuals/archive/cpm22htm/ch5.htm#Sect... So, yes, the DOS function calls were designed with CP/M backwards compatibility in mind, and it says so right in the manual. Kind of.

cpeterso 10y ago

So how does one fix bugs in ProDOS 2.0.3? I assume John Brooks does not have the ProDOS source code. Is he patching the old binaries?

teach 10y ago
I'm going to go out on a limb and say that ProDOS was originally written directly in assembly and not compiled from a higher-level language. Disassembling is pretty trivial compared to de-compiling.

StillBored 10y ago

Hmm, Still looks like it has the 32M (IIRC) partition limit. There are GSOS drivers to work around this, but not for generic 8-bit prodos (AFAIK). Frankly, the II line was always slow moving (the IIE was sold commercially longer than any other computer without any significant upgrades). Which is why was such a great learning computer, there were only a couple models, very well documented, and hacked on to uncover every tiny little trick/edge case. Now days, I look at 6502 assembly and wonder how I managed to get anything done with such a restrictive stack/etc.