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.
Microsoft has just released the code for version 4.0 of MS-DOS. The operating system was released in 1988, 36 years ago, and was a notable upgrade from earlier releases. For example, it added support for hard drive partitions up to 2GB. Microsoft had also planned this version of MS-DOS to be multitasking-capable and actually shipped a “multitasking” version of the OS to some markets, but IBM had other plans for the release, so it wasn’t too widespread.