MS-DOS 1.1, 2.0 Source Code Released

In cooperation with the excellent Computer History Museum in Mountain View, Microsoft released the source code to MS-DOS 1.1, MS-DOS 2.0, and Microsoft Word for Windows 1.1a.

Here’s hoping that this is a sign of things to come and Microsoft will also release the source code to historic versions of Windows 1.x, 2.x and 3.x, further versions of MS-DOS—and maybe even OS/2 1.0!

The poor CHM server is currently suffering from a severe overload so actually looking at the goodies will have to wait…

Later: Yes, it’s the real thing. There’s the MS-DOS source code, and even more—someone left in a few WordStar overlay files. Somehow I doubt Microsoft is legally allowed to redistribute files with “COPYRIGHT (C) 1982, MICROPRO INTERNATIONAL” in them… oh well.

The DOS 1.1 source code seems to be a somewhat random collection of files saved by Tim Paterson, as used by SCP.

The 2.0 source code appears to have been taken from a MS-DOS 2.0 OAK… which means no useful IO.SYS source code. On the other hand, there is a smattering of documentation.

All in all, fun stuff!

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52 Responses to MS-DOS 1.1, 2.0 Source Code Released

  1. Andreas Kohl says:

    Why not simply using the included SCP 8086 assembler or easier the MASM 1.10? And don’t ask which machines where used for building.

  2. buricco says:

    Regarding io.sys, I’d be willing to create a new one, but my x86-fu isn’t good enough.

    I’ve rolled msdos.sys and command.com from 1.25, though, didn’t take a lot of work but it did take an ancient MASM.

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