Nancy Blair

USA TODAY

SAN FRANCISCO — Nostalgic for MS-DOS, anyone? How about 'early 90s-vintage Word?

Microsoft on Tuesday "dusted off" the source code for early versions of the iconic MS-DOS operating system and '90s-vintage Word for Windows and released it to the public for the first time.

The tech giant partnered with the Computer History Museum in San Jose on the project. The museum will make available the source code for MS DOS1.1 and 2.0 and Microsoft Word for Windows 1.1a "to help future generations of technologists better understand the roots of personal computing," the company said.

Microsoft got its start in PCs through a partnership with IBM. Before the consumer friendly computer interfaces we're all familiar with today, MS-DOS required you to type in instructions to run programs, delete files and the like.

"Version 1.1 fits an entire operating system – limited as it was – into only 12K bytes of memory, which is tiny compared to today's software," museum chairman Len Shustek noted in a release.

The first DOS-based version of Microsoft Word came out in 1983, designed for use with a mouse. Its top competitor back in the day was Word Perfect, which is now owned by Corel.

It wasn't until 1989, when Word for Windows was released, that Word "became a blockbuster" for the company, Microsoft noted in a press release. Within four years of release it was generating over half the revenue of the global word-processing market, the company said.

"We think preserving historic source code like these two programs is key to understanding how software has evolved from primitive roots to become a crucial part of our civilization," says Shustek.