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

Business Home Business Companies Microsoft Microsoft finally open sources DOS 1.0 - and it's so much more than the code 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. Written by Steven Vaughan-Nichols, Senior Contributing EditorSenior Contributing Editor April 28, 2026 at 11:45 a.m. PT MicrosoftFollow ZDNET: Add us as a preferred source on Google.ZDNET's key takeawaysPC-DOS 1.00 would lead to Microsoft becoming computing's top dogMicrosoft continues to embrace open source. The source code and annotations provide insight into the operating system's earliest days.Before "Micro Soft" became Microsoft, Bill Gates wrote BASIC interpreters.

…

Excerpt limited to ~120 words for fair-use compliance. The full article is at ZDNET.