This historic OS was not stored digitally, so a fleet of historians have transcribed the source code from ancient print-outs in order to make it open source

Retro 1990s style beige desktop PC computer and monitor screen and keyboard. 3D illustration.

I'm dating myself here, but the operating systems I remember most clearly banging my head against in my youth were Windows 95 and Windows XP. Obviously, plenty of computer interface history predates the panel-style design we're so familiar with now, and Microsoft has announced fresh efforts to preserve this.

Microsoft has shared the source code for 86-DOS 1.00, a precursor to MS-DOS, via GitHub. Uploaded on the vintage operating system's 45th birthday, a recent blog post explains that this preservation effort was a more serious undertaking than simply unearthing a bunch of ancient floppy disks and lifting the data. It turns out that the source code for this early version of 86-DOS was not stored digitally.