Microsoft opens door to the past by releasing 86-DOS and PC-DOS 1.00

Microsoft released source code for 86-DOS 1.00 and PC-DOS 1.00, including kernel snapshots, utilities like CHKDSK, and scanned assembler printouts discovered in Tim Paterson's garage. The release preserves the analog artifacts of how early microcomputer operating systems evolved in the late 1970s-80s, with physical printouts serving as a timeline of features, errors, and fixes. This follows Microsoft's previous release of MS-DOS 4.0 source code.