Open Source · Tom's Hardware
45 years later, earliest DOS source code transcribed from a stack of old printouts found in a garage
Compiled by KHAO Editorial — aggregated from 1 outlet. See llms.txt for citation guidance.
◌ Single Source
Microsoft continues to make some of the earliest chapters of its operating system history open-source and freely available.
Key facts
- Earlier this week, it announced that Tim Paterson's DOS listings, containing source code of the 86-DOS 1.00 kernel, various PC-DOS 1.00 pre-release kernels and utilities, and the Microsoft BASIC-86
- In April 2024, they reported on Microsoft releasing the code for MS-DOS 4.00 under the generous MIT License, allowing tinkerers free rein
- The earliest DOS source code was found on printer paper in Tim Paterson's garage so they've open sourced it on 86-DOS 1.00’s 45th anniversary
- In the GitHub repository, you can see 86-DOS’s transformation into the PC-DOS 1.00 kernel, alongside code for some well-known utilities (still in use today) such as CHKDSK
Summary
The earliest DOS source code was found on printer paper in Tim Paterson's garage so they've open sourced it on 86-DOS 1.00’s 45th anniversary! If you head on over to the GitHub page to snag the code, you will see a photo of Tim Paterson standing in his garage with a pile of yellowed dot matrix printouts in the foreground. Probably more important to tinkerers, though, is the fact that the work of transcribing the printed code has been completed (for those three mentioned wares). In case you aren’t familiar with the place of 86-DOS (or Tim Paterson) in Microsoft’s history, here's a short refresher.