After publishing open-source versions of MS-DOS years ago for versions 1.25 and 2.0, Microsoft and IBM have now announced that MS-DOS 4.0 has been open-sourced under an MIT license.
MS-DOS 4.0 is now open-source and available on GitHub. This open-sourcing of MS-DOS 4.00 is primarily done for historical purposes. The MS-DOS 4.0 code can be tested on modern PCs with the likes of the PCem and 86box emulators.
More details for those interested via the Microsoft Open-Source Blog. The MS-DOS source code can be pulled from GitHub.
Yeah, for those interested in reinventing the flat tire. That's bullshit, fuck off Microsoft. They wouldn't open source anything you could use that might have a hope in Hell of being ported to modern hardware for firmware flashing etc. (but we already have open DOS implementations for that).
