Microsoft has released the source code of the operating systems 86-DOS 1.00 and PC-DOS 1.00 under the MIT license, along with the runtime libraries of the Microsoft BASIC-86 compiler, the SCP assembler, and the utilities CHKDSK and EDLIN. PC-DOS 1.00 is notable for being the first release of DOS for IBM PC computers. The code was recovered as part of a project to reconstruct the code of the early versions of DOS for the CPU 8086 by scanning and transcribing archival paper prints created in 1981 and 1982.
Source: opennet.ru
