The source code for MS-DOS v4.00, which was developed in collaboration with IBM, has been released by Microsoft for historical reference.

MS-DOS: The original sources of MS-DOS 1.25, 2.0, and 4.0 for reference purposes

This repo contains the original source-code and compiled binaries for MS-DOS v1.25 and MS-DOS v2.0, plus the source-code for MS-DOS v4.00 jointly developed by IBM and Microsoft.

The MS-DOS v1.25 and v2.0 files  were originally shared at the Computer History Museum on March 25th, 2014 and are being (re)published in this repo to make them easier to find, reference-to in external writing and works, and to allow exploration and experimentation for those interested in early PC Operating Systems.

License

All files within this repo are released under the  MIT License as per the  LICENSE file stored in the root of this repo.

For historical reference

The source files in this repo are for historical reference and will be kept static, so please don’t send Pull Requests suggesting any modifications to the source files, but feel free to fork this repo and experiment .

This project has adopted the  Microsoft Open Source Code of Conduct. For more information see the  Code of Conduct FAQ or contact  opencode@microsoft.com with any additional questions or comments.

GitHub - microsoft/MS-DOS: The original sources of MS-DOS 1.25, 2.0, and 4.0 for reference purposes