Microsoft releases the oldest DOS source code yet, tracing back to 86-DOS
Microsoft has published what it calls the earliest DOS source code discovered to date, including the 86-DOS 1.00 kernel, PC-DOS 1.00 development snapshots, and utilities like CHKDSK, all in the same GitHub repository. A team of historians known as the DOS Disassembly Group transcribed decades-old printouts for preservation, noting that the release predates the MS-DOS branding and follows earlier open-source MS-DOS releases from 2014, 2018, and 2024.
