MS-DOS 4.0 From 1988 Is Now Open-Source Software

Microsoft Disk Operating System, or MS-DOS for short, was the operating system that powered early PCs and served as the underlying framework for early versions of Microsoft Windows. Some older versions have been released as open-source software over the past few years, giving us a better look at early computing history, and now the code for the 1988 release of MS-DOS 4.0 is available.