Mountain View’s Computer History Museum will preserve the code as part of an exhibit showcasing early computer programs.

MS DOSProducts 1523 583072E2 Microsoft makes source code for MS DOS and Word 1.1 public

Microsoft announced Tuesday that it was publishing the source code for the original MS-DOS and Word for Windows in an effort to help the public understand the early days of computing and programming.

The code released will be for MS-DOS 1.0, 1.1 and 2.0 as well as Word for Windows 1.1a.

“MS-DOS and Word for Windows built the foundation for Microsoft’s success in the technology industry,” said Microsoft Research’s Roy Levin, in a blog post. “By contributing these source codes to the Computer History Museum archives, Microsoft is making these historic systems from the early era of personal computing available to the community for historical and technical scholarship.”

The inception of MS-DOS began when IBM approached Microsoft to make an operating system for its upcoming personal computer. Microsoft was already licensing its BASIC language to IBM, but IBM wanted something more. The scope of creating an entire operating system was far beyond Microsoft’s resources available at the time, but that didn’t stop Bill Gates: he bought the full rights to DOS from a relatively unknown firm called Seattle Computer Products for $50,000.

When Seattle Computer Products’ proprietor Rod Brock caught wind of the profits Microsoft was making from its deal reselling DOS to IBM, Brock decided to sell the company and its intellectual property outright to a rival PC maker. Microsoft initially objected to this, and Brock sued for $60 million. The two parties settled out of court for $925,000, and Microsoft confirmed its rights and license to DOS.

Microsoft later licensed DOS to other computer manufacturers as MS-DOS.

Part of the IBM-Microsoft-Seattle Computer products affair is dramatized in the excellent film Pirates of the Silicon Valley:

To put things into perspective, the entire source code of the MS-DOS 1.1a operating system amounted to 12KB.

MS-DOS and Word for Windows are the latest additions to the Computer History Museum’s growing collection of source code for significant programs, which includes the original version of Adobe’s Photoshop.

You can download the source code for MS-DOS here, and Word for Windows here.