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Re: Decompiling the Reference Diskette and associated programs

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On 7/30/26 10:57, Josh Rodd wrote:
> Friends,
> 
> One of the major annoyances with using genuine IBM PS/2s (or even
> emulated ones) is dealing with the Reference Diskette. I decided to
> tackle this by first taking an inventory of what, exactly, the Reference
> Diskette even is, what it does, and what the various programs on it do,
> with a goal towards eventually replacing it with a far more compact
> program, a much more compact representation of ADFs, and an ability to
> run from things other than a diskette (such as a ROM BIOS, or, in the
> most extreme cases, something hand-typed into ROM BASIC). Part of the
> goal here is to make a PS/2 usable when it does not have a usable
> diskette drive; currently, the only other way to set up such a system is
> to perform RIPL from a Token Ring card.
> 
> I decided to start my focus on the Type 2 PS/2 Model 80, since (a) I
> have the most personal experience with that machine's hardware, its
> BIOS, and its ABIOS; and (b) it has some of the most thorough emulation
> in 86Box. The Mod 50/60 has some problems in 86Box (relating to memory
> sizing), and the Type 1 and Type 3 aren't 100% accurate.
> 
> So far I have found version 1.06 and 1.21 of the Reference Diskette. (My
> Type 2 machine came with 1.21 back in the day, but that really just
> meant that I went to the library at the local IBM office and pulled one
> of the hundreds of Guides to Operations off of the shelf and ended up
> with that version.)
> 
> Some preliminary analysis so far:
> 
> 1.06 is byte for byte identical to PC-DOS 3.30. That's going to motivate
> me to work on analysing the 1.06 refdisk first, since I don't have to
> worry about DOS being different in some subtle way. (1.06 had the cute
> "tutorial" on it, complete with pixel art of a Mod. 70 and 80 chassis.)
> 
> 1.21 is a bit odder. It has a PC-DOS revision that is newer than 4.01:
> it has some bugs fixed regarding printer handling and supports multiple
> EMM modes. It definitely contains code that is not in the MS-DOS 4.01
> source release. The DOS on it will be worthy of future analysis just to
> figure out what it is, because it's not PC-DOS 5.00 either, and it's not
> Multitasking MS-DOS 4. Maybe some OS/2 expert can tell me if there was
> ever an "oddball" DOS found in an OS/2 beta release.
> 
> On a different topic... how hard is burning a PROM set (well, EEPROM
> these days) for a PS/2? The end goal here is to eventually cram a
> reference diskette inside the ROM.

That sounds cool.  There are some machines where slots are at a premium 
so it would be ideal there.  For those where it isn't, maybe easier to 
extend something like the McIDE which I think has boot hooks, and it 
could all reasonably fit in an external flash boot ROM BIOS, including 
all system types and all ADFs?

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Decompiling the Reference Diskette and associated programs "Josh Rodd" <joshua.at.rodd.dot.us@rodd.us> - 2026-07-30 17:57 +0000
  Take me to the PROM Re: Decompiling the Reference Diskette and associated programs Louis Ohland <ohland@charter.net> - 2026-07-30 20:07 -0500
  Re: Decompiling the Reference Diskette and associated programs Kevin Bowling <kevin.bowling@kev009.com> - 2026-07-30 19:59 -0700
    Interesting Re: Decompiling the Reference Diskette and associated programs Louis Ohland <ohland@charter.net> - 2026-07-30 23:53 -0500
      Catching the Night Train Re: Interesting Re: Decompiling the Reference Diskette and associated programs Louis Ohland <ohland@charter.net> - 2026-07-30 23:58 -0500
      Re: Interesting Re: Decompiling the Reference Diskette and associated programs Kevin Bowling <kevin.bowling@kev009.com> - 2026-07-30 23:08 -0700
        Re: Interesting Re: Decompiling the Reference Diskette and associated programs Louis Ohland <ohland@charter.net> - 2026-07-31 08:26 -0500
          Re: Interesting Re: Decompiling the Reference Diskette and associated programs Kevin Bowling <kevin.bowling@kev009.com> - 2026-07-31 10:41 -0700

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