Microsoft posted on its open source blog on April 28 that the company has been continuously opening up the earliest important data in the history of Microsoft operating systems in the past few years: in 2018, it reopened the source code of MS-DOS 1.25 and 2.11, and in 2024 it provided the source code of MS-DOS 4.0 to the public; now, it coincides with 86-DOS On the 45th anniversary of the birth of 1.00, Microsoft announced that it will continue to advance this work and preserve and make public the earliest batch of DOS source code materials discovered so far to facilitate research, preservation, and satisfy the exploration interests of the industry and enthusiasts.
Microsoft says the work is about more than just uploading code to GitHub. Software history exists not only in the source code itself, but also in scans, internal documents, assembler printouts, and various traces of the "analog era" left over from the development of operating systems in the late 1970s and early 1980s. Microsoft emphasizes that these historical contexts are also indispensable if we want to truly understand where today's platforms come from.
The new material released this time provides an earlier window than ever into the development process of PC-DOS 1.00. PC-DOS 1.00 is the first official version of DOS on the IBM PC platform. Microsoft said that a team of historical researchers and digital preservationists, led by Yufeng Gao and Rich Cini, located, scanned and transcribed a large number of DOS-era source code print lists written by DOS author Tim Paterson.
According to Microsoft's disclosure, this batch of information includes the 86-DOS 1.00 kernel source code, multiple snapshots of the PC-DOS 1.00 kernel development stage, and the source code of well-known utility tools such as CHKDSK. What is even more striking is that not only the assembly source code listing is preserved, but also the printed listing of the assembler itself. Microsoft believes that these materials provide an extremely rare perspective for the outside world to understand how MS-DOS/PC-DOS was formed step by step, and to see the true appearance of operating system development in that era, rather than a version compiled after the fact.
Microsoft further pointed out that these materials are not packaged and officially released operating system versions in the traditional sense. On the contrary, many of them are more like records of work status at a certain point in time, with handwritten notes left by Tim Paterson himself. Microsoft describes it as "a printed commit history of a Git repository": they connect a clear timeline, showing which features were added when, what errors occurred during the development process, and how they were later corrected. This batch of physical materials has also been donated by Tim Paterson. In the future, the public will be able to see these original files that are still "telling history" at the Interim Computer Museum.
In the article, Microsoft thanks all those who participated in the compilation, review and disclosure of these materials, and points out that this kind of "software archeology" work requires investment from many aspects such as legal review, archival organization and technical verification, and is of great significance to preserving the common history of the entire industry.
For those who want to study further, Microsoft recommends consulting Yufeng Gao's website, Rich Cini's website, and Joshua's research results on OCR processing of print lists. At the same time, Microsoft also stated that the outside world can already go to the DOS-History/Paterson-Listings project on GitHub to view the relevant scan lists and OCR-organized code; Microsoft also cooperates with the maintainers of the project to open it under the MIT license through pull requests, making it convenient for researchers, amateurs, and followers of technology history.
learn more:
https://github.com/DOS-History/Paterson-Listings