List of operating systems:

Table of contents
1 Historically Important Early OS
2 Early Proprietary Microcomputer OS
3 Unix-like and other POSIX compliant systems
4 Generic/Commodity, non-UNIX and other
5 Acorn
6 Amiga
7 Atari ST
8 Apple/Macintosh
9 Be Incorporated
10 Digital/Compaq/HP
11 IBM
12 Microsoft
13 Personal digital assistants (PDAs)
14 See also

Historically Important Early OS

Early Proprietary Microcomputer OS

  • Apple Computer (inital version was ROM'd firmware together with Integer BASIC; later versions included a MIcrosoft BASIC)
  • Business Operating System (BOS) - cross platform, command-line based
  • Commodore PET, Commodore 64, and Commodore VIC-20,
  • The very first IBM-PC (3 OS offered to start, USCD P-system, CPM-86, PC-DOS)
  • Sinclair Micro and QX, etc
  • TRS-DOS, ROM OS's (largely Microsoft BASIC implementations with file system extensions)
  • TI99-4
  • Flex (by Technical Systems Consultants for Motorola 6800 based microcomputers: SWTPC, Tano, Smoke Signal Broadcasting, Gimix, etc)
  • FLEX9 (by TSC for Motorola 6809 based micros)
  • mini-FLEX (by TSC for 5.25" disks on 6800 based machines)

Unix-like and other POSIX compliant systems

  • AIX (Unix from IBM)
  • AtheOS (continued under the Syllable code-fork)
  • A/UX (Unix-based Apple OS from the beginning of the 1990s)
  • BSD (Berkeley Software Distribution, a variant of Unix for DEC VAX hardware)
  • Cromix (Unix-emulating OS from Cromemco)
  • Coherent (Unix-emulating OS from Mark Williams Co. for PC class computers)
  • DNIX
  • Digital UNIX (which became HP's Tru64)
  • FreeBSD (one of the open source outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
  • GNU/Hurd
  • Linux (commonly called GNU/Linux, the name of the entire system taken together
  • HP-UX from HP
  • IRIX from SGI
  • Linux (see GNU/Linux)
  • Mac OS X from Apple Computer
  • Minix (study OS developed by Andrew Tannenbaum in the Netherlands)
  • Menuet
  • NetBSD (one of the post-CSRG open source varieties of BSD)
  • OS-9(for Morotola 6809 based machines)
  • OS-9/68k (for Motorola 680x0 based machines)
  • OS-9000 (OS-9 written in C for intel and other processors)
  • OS/360
  • OSF/1
  • OpenBSD (one of the post-CSRG opern source varieties of BSD)
  • Plan 9 (networking OS developed at Bell Labs)
  • QNX (POSIX, microkernel OS; usually a real time embedded OS)
  • RiscOS
  • SCO UNIX (from SCO, bought by Caldera and re-renamed SCO)
  • Solaris from Sun Microsystems
  • SunOS from Sun Microsystems (became Solaris)
  • System V (a release of AT&T Unix, 'SVr4' was the 4th minor release)
  • UNIX (OS developed at Bell Labs ca 1970 initially by Ken Thompson)
  • UNIflex (Unix emulating OS by TSC for DMA-capable, extended addresses, Mototola 6809 based computers; eg SWTPC, GIMIX, ...)
  • Ultrix (DEC's first version of Unix for VAX and PDP-11, based on BSD)
  • UniCOS
  • Xenix (Microsoft's licensed version of Unix for various hardware platforms)
  • z/OS (latest version of IBM mainframe OS)

Generic/Commodity, non-UNIX and other

  • AOS, now called Bluebottle (a concurrent and active object update to the Oberon operating system)
  • AROS (Amiga Research Operating System)
  • Bluebottle (see AOS)
  • Control Program/Monitor-80 (CPM operating system)
  • MP/M-80 (Multi programming version of CP/M-86 from Digital Research)
  • UCSD P-system (portable complete programming environment/operating system developed by a long running student project at the Univ Calif/San Diego; directed by Prof Ken Bowles; written Pascal)
  • FLEX9 (by TSC for Motorola 6809 based machines; successor to FLEX, which was for Motorola 6800 CPUs)
  • SSB-DOS (by TSC for Smoke Signal Broadcasting; a variant of FLEX in most respects)
  • CP/M-86 (CP/M for Intel 8088/86 from Digital Research)
  • DESQView (windowing GUI for MS-DOS, ca 1985)
  • DR-DOS (MS-DOS compatible OS from Digital Research, later from Novell, Caldera, ..; still being used for special purpose projects)
  • FreeDOS (an open source MS-DOS workalike)
  • GEM (GUI for MS-DOS / DR-DOS from Digital Research)
  • MS-DOS (Microsoft developed OS for IBM PC compatible machines)
  • PC-DOS (IBM's version of DOS for PC machines)
  • Mach (from OS kernel research at CMU; see NextStep)
  • NewOS
  • Oberon operating system/(developed at ETH-Zurich by Niklaus Wirth et al) for the Ceres and Chameleon workstation projects. see also Oberon programming language
  • OS/2 (Windows/MS-DOS compatible operating system developed originally at Microsoft and taken over by IBM; a considerable technical improvement on both early Windows and MS-DOS. Not a commercial success. The Odin open source project adds Windows 9x compatibility to OS/2. See for details)
  • OS-9 (Unix emulating OS from Microware for Motorola 6809 based microcomputers)
  • OS-9/68k (Unix emulating OS from Microware for Morotola 680x0 based computers; developed from OS-9)
  • OS-9000 (portable Unix emulating OS from Microware; one implementation was for Intel x86)
  • SkyOS
  • TripOS
  • QDOS (developed at Seattle Computer Products by Tim Paterson for the new Intel 808x CPUs; also called SCP-DOS; licensed to Microsoft -- became MS-DOS/PC-DOS)
  • VisiOn (first GUI for early PC machines, not commercially successful)
  • VME by International Computers Limited (ICL)
  • MorphOS (by Genesi)
  • NetWare (by Novell)
  • NeXTStep (which, more or less, became Mac OS X by NeXT)
  • Plan 9, Inferno (networked OS originally from Bell Labs Computer Research)
  • Primos by Prime Computer
  • BS2000 by Siemens AG



Atari ST


Be Incorporated




Personal digital assistants (PDAs)

  • Palm OS from Palm Inc; now spun off as PalmSource
  • Pocket PC from Microsoft
  • EPOC originally from Psion (UK), now from Symbian, preferred name now is Symbian OS
  • Windows CE Windows Compact Edition, from Microsoft

See also