Before Windows got its windows, Microsoft used an operating system called DOS. It didn't look fancy, as it was about as graphically intense as the current-day Command Prompt, but it still laid the foundation for the Windows PCs we use today. Now, Microsoft, in collaboration with IBM, has released all of MS-DOS 4.0's onto GitHub, thus allowing people to archive and use this amazing piece of technological history.
Microsoft makes MS-DOS 4.0 open-source, preserving the influential tool forever
