نظام DOS

Win95 has roots in DOS

WinNT has roots in Vax systems by DEC

MacOS roots are in Xerox Parc and Mach (Carnegie-Mellon)

OSX based on BSD

BeOS

OS/2

Haiku

PalmOS

Android

iOS

Intel, PowerPC, Motorola mac clones in the 90s …

unix-like systems vs Windows

LibreOffice history (some code stiill dates back 30 years)