Microsoft Open-Sources 86-DOS 1.00 Under MIT — Earliest Known DOS Source Code Released for 45th Anniversary
r/programming·medium signal
Microsoft released the earliest known DOS source code on April 28 to mark the 45th anniversary of 86-DOS 1.00 (500 upvotes on r/programming). The release includes kernel sources, PC-DOS development snapshots, CHKDSK utilities, and the original assembler itself — all transcribed from physical continuous-feed paper printouts preserved by Tim Paterson since 1981. Available as MIT-licensed on GitHub (DOS-History/Paterson-Listings), this is significant for computing history preservation.