Microsoft releases MS-DOS 4.0 source code and floppy images through an open-source license

TechSpot— Ten years after releasing the source code of MS-DOS 1.25 and 2.0, Microsoft is making yet another contribution to the world of open-source software preservation. Working in partnership with IBM and "in the spirit of open innovation," the company has released the source code of MS-DOS 4.00 under an MIT license.Read Entire Article

ZDNet—It's baaack! Microsoft and IBM open source MS-DOS 4.0. It's no joke. Microsoft and IBM have joined forces to open-source the 1988 operating system MS-DOS 4.0 under the MIT License. Why? Well, why not?As Scott Hanselman, Microsoft's VP of the developer community, and Jeff Wilcox, head of Microsoft's Open Source Programs Office, recount in Microsoft's Open Source Blog, "a young English researcher named Connor 'Starfrost' Hyde corresponded recently with former Microsoft Chief Technical Officer Ray Ozzie" about the relationship between DOS 4,...

Ars Technica—Microsoft open-sources infamously weird, RAM-hungry MS-DOS 4.00 release. DOS 4.00 was supposed to add multitasking to the OS, but it was not to be.

Neowin—Microsoft explains how you can run MS-DOS 4.00 that it officially open sourced today. Microsoft earlier today, in collaboration with IBM, announced that it is open-sourcing the MS-DOS 4.00 source code. The company has explained what was special about it and how to run it.