O.S.

Different type operating systems:
DOS
Mac
Windows 3.1
OS/2
Windows 95
Windows NT
Windows 98
Windows ME
Windows 2000
Windows XP
Windows Vista
Window 7
Window 10
Unix
Linux (With different flavors)

1. Red hat Linux
2. Fedora
3. Centos
4. Oracle Rad Hat

AmigaDOS
VMS