FreeDOS, the free and open-source alternative to Microsoft DOS (MS-DOS), just released a new major update. It still has excellent compatibility with MS-DOS software, including Windows 3.1 and earlier, ...
In context: Back in 1980, Tim Paterson was creating a new operating system he called QDOS or Quick and Dirty Operating System. The system was later renamed 86-DOS, as it was being designed to run on ...
TL;DR: Microsoft will likely never release the original source code of Windows into the wild, but the company is clearly interested in sharing important episodes of its software development history.