Microsoft on Tuesday “dusted off” the source code for early versions of MS-DOS and Microsoft Word for Windows released it to the public for the first time. The tech giant Microsoft partnered with the CA-based Computer History Museum in San Jose on the project.

The Museum makes the source code for MS DOS 1.1 and 2.0, as well as Microsoft Word for Windows 1.1a are available for download via this page on the site. It is made public under a non-commercial license that prohibits re-publication on any other website. The company said “to help future generations of technologists better understand the roots of personal computing”.

Early Beginnings of the Iconic Software

IBM approached Microsoft to work on a project code-named “Chess.” The Company signed the contract with IBM in November 1980. At the time, Microsoft provided the BASIC language interpreter for IBM.

However, IBM had other plans and asked Microsoft to create an operating system. Hence the Microsoft licensed an operating system from variously called QDOS (Quick and Dirty Operating System”) and 86-DOS. This would become the basic of PC-DOS and MS-DOS.

MS-DOS was a renamed version of 86-DOS, written by Tim Paterson of Seattle, released in August 1980. Microsoft bought 86-DOS 1.10 for $75,000 in July 1981, and renamed it MS-DOS.

PC DOS version 1.0, which supported only floppy disks, IBM first released their PC in August 1981. Version 2.0 was released with the IBM PC-XT in March of 1983, designed for use with a mouse.

In 1989, Word for Windows was released, and within four years it 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 in a statement.