A decade after releasing the source code for MS-DOS 1.1 and MS-DOS 2.0, Microsoft has open sourced a (slightly) more recent operating system: MS-DOS 4.0. First released in 1988, you can now download ...

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.

That screenshot seems to be MS-DOS 5.0 or later. How many end users had hard drives when 4.0 was released? Click to expand... We had a 20MB hard drive in a PC-XT clone made by Sanyo which was running ...

Halcyon DOS Days: Back in the command prompt days, DR-DOS was one of the main competitors to MS-DOS in the operating system market. Those days are long gone, but a mysterious developer is reviving the ...