Microsoft open-sources “the earliest DOS source code discovered to date”

Several times in the last couple of decades, Microsoft has released source code for the original MS-DOS operating system that kicked off its decades-long dominance of consumer PCs. This week, the ...
Neowin

A quick look back at Microsoft's first computer operating system, Xenix

Long before Windows, and even before MS-DOS, Microsoft sold a Unix-based operating system it called Xenix in 1980. It was the first OS made by the company, but it eventually sold it off in 1987. On ...
XDA Developers on MSN

The virtual OS museum lets you relive the glory days of Windows 3.1, DOS, PalmOS, and more

This is a real operating system blast from the past.
ZDNet

Microsoft finally open sources DOS 1.0 - and it's so much more than the code

PC-DOS 1.00 would lead to Microsoft becoming computing's top dog Microsoft continues to embrace open source. The source code and annotations provide insight into the operating system's earliest days.
How-To Geek on MSN

I didn't realize MS-DOS was training me for Linux

How early DOS command-line skills helped me climb the Linux learning curve.