Microsoft opens PC-DOS 1.0, turning DOS's origin into a teachable archive
Microsoft has released the PC-DOS 1.00 source code plus Tim Paterson’s notes under the MIT license, turning the earliest DOS into a browsable, educational Git‑like archive. The materials include not only the assembler listings but a point‑in‑time history, clarifying DOS versioning and showing how 8086‑era development worked. Despite its tiny scope—160KB floppy disks, no subdirectories or hard disks—PC-DOS 1.00 laid the groundwork for Microsoft’s rise during the IBM PC era, and the open release lets researchers and retrocomputing fans clone, build with modern toolchains, and learn from the original OS design.