Sun September 30 2018, 12:00am / Darren

MS-DOS logoAs part of Microsoft's recent open source initiative, they have (re-)released the source code for MS-DOS 1.25 and 2.0 as open source. It's a "re-release" because the code was already released back in 2014 via the Computer History Museum, but they have recently added the code to their MS-DOS Github repo (Microsoft now owns Github of course ...) to make it more accessible.

Here are some of their notes regarding the code:

  1. All the source for MS-DOS 1.25 and 2.0 was written in 8086 assembly code 
  2. The source code for the initial release of 86-DOS dates from around December 29th 1980 
  3. The MS-DOS 1.25 code dates from around May 9th 1983, and is comprised of just 7 source files, including the original MS-DOS Command-Line shell - COMMAND.ASM! 
  4. MS-DOS 2.0 dates from around August 3rd 1983, and grew considerably in sophistication (and team size), and is comprised of 100 .ASM files 
  5. There are some interesting documentation (.TXT, .DOC) files interspersed with the source and object files - many are well worth a read, as are many of the source code comments!

View, download, or fork the MS-DOS ASM code at:

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