Microsoft is releasing the source code for early versions of MS-DOS and Word for Windows, working with the Computer History Museum. The museum will make available the source code for MS DOS 1.1 and 2.0 and Microsoft Word for Windows 1.1a.
Back then MS-DOS had less than 300KB (yes, kilobytes) of source code. Microsoft’s DOS-based version of Word, first released in 1983, was not a success against the dominant word processor of that era, WordPerfect. The 1989 release of Word for Windows changed all that.
[Image courtesy: Microsoft]