Operating Systems

Operating Systems are what make computers do what they do, managing their resources and overseeing input, output, and data storage and retrieval. They form a platform on which applications software (programs, apps, programming languages, etc.) runs. Operating systems (or OSs) can be proprietary or free, closed or open source, and specific to one manufacturer's hardware or portable between multiple hardware platforms.

A category of particular interest to fans of nonproprietary software are those OSs that are developed independently of a closed proprietary system and allow the use of software originally developed for those systems to run without them. Ideally as well as being binary compatible at the user level, they are also driver compatible (allowing the use of older hardware as well).

Proprietary OSs

Mainframe

• IBM System/360
• Multics
• TOPS-10
• TOPS-20

Minicomputer

• Unix
• VAX/VMS

Personal computer

• Apple II DOS
  • ProDOS
• MacOS
  • OS X
• OS/2
• PC-DOS / MS-DOS
• Windows
  • Windows NT
  • Windows 2000
  • Windows XP
  • Windows Vista
  • Windows 7
  • Windows 8

Mobile device

• Android
• iOS
• Windows Mobile

Free OSs

• FreeBSD
• Linux

Nonproprietary OSs emulating proprietary ones

(see also Emulation Software)

• FreeDOS - DOS
• ReactOS - MS Windows - see also Wine
• Haiku - BeOS