Microsoft today released the source code for MS DOS 1.1 and 2.0 as well as Microsoft Word for Windows 1.1a. With the help of the Computer History Museum, the move means means this code is now available to the public.

MS-DOS was a renamed version of 86-DOS, written by Tim Paterson of Seattle Computer Products and initially released in August 1980. Microsoft hired Paterson in May 1981, bought 86-DOS 1.10 for $75,000 in July, and renamed it MS-DOS. Microsoft released the first DOS-based version of Microsoft Word in 1983. In 1989, Word for Windows arrived, and within four years was generating over half the revenue of the worldwide word-processing market.


“Thanks to the Computer History Museum, these important pieces of source code will be preserved and made available to the community for historical and technical scholarship,” Microsoft Research managing director Roy Levin said today. We agree, although it’s not clear what took so long.

Computer History Museum

Image Credit: Robert Scoble