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

Our gifting experts are obsessively searching for holiday gifts that are unique, thoughtful and suitable for any budget. Want a blast from the past? Microsoft just open-sourced its very first operating system, offering a rare insight into the PC's earliest days. Follow ZDNET: Add us as a preferred source on Google. Before “Micro Soft” became Microsoft, Bill Gates wrote BASIC interpreters. Microsoft’s first shipping operating system was a Unix distro called Xenix. Then, in 1980, Microsoft got its shot at the big time: IBM needed an operating system for its planned IBM PC and asked Gates if he could deliver one. You betcha! The rest is history. Now, Microsoft has released the source code and notes for PC-DOS 1.00, the first DOS release for the IBM PC. Also: 5 ways your Windows updates are about to get a lot less painful Microsoft’s AT&T Unix license didn’t give the company the leeway to port Xenix to the x86 IBM PC. That would have led to a very different world with Unix as the top desktop operating system from then until today. In another reality, Linus Torvalds could have been Microsoft Unix CTO. In the real world, Gates and company had to whip up an operating system as quickly as