Various OS used in Computers

Microsoft Corporation (Windows)
NCR Corporation (TMX)
Acorn Computers (RISC OS)
Amiga Inc
Apple Inc (Mac OS)
Apollo Computer (Domain/OS)
Atari (Atari OS)
BAE Systems
Be Inc
Bell Labs (UNIX)
Digital Research, Inc (DOS)
Fujitsu (Towns OS)
Google (Android)
Hewlett-Packard (HP-UX)
Intel Corporation (iRMX)
IBM
LynuxWorks (LynxOS)
NCR Corporation (TMX)
Samsung Electronics (Bada)
Unisys
UNIVAC