Operating systems can be categorized by technology, ownership, licensing, working state, usage, and by many other characteristics. In practice, many of these groupings may overlap.


Acorn Computers

Amiga Inc.

Apollo Computer

Apple Inc.

For Apple II

For Apple III

  • SOS (Sophisticated Operating System)

For Apple Lisa

  • Lisa OS

For Apple Newton

Classic Mac OS

Unix-like operating systems


BAE Systems

Be Inc.

Burroughs Corporation

Control Data Corporation

  • COS (Chippewa Operating System)
    • SIPROS (for Simultaneous Processing Operating System)
    • SCOPE (Supervisory Control Of Program Execution)
    • MACE (Mansfield and Cahlander Executive)
      • KRONOS (Kronographic OS)
        • NOS (Network Operating System)
          • NOS/BE NOS Batch Environment

Convergent Technologies

Data General


  • CTOS Z-80 based, Cassette Tape Operating System for early desktop systems. Capable of up to 8 simultaneous users. Replaced by DataPoint DOS.
  • DOS Intel 808x/80x86-based, Disk Operating Systems for desktop systems. Capable of up to 32 users per node. Supported a sophisticated network of nodes that were often purpose-built. The name DOS was used in these products login screens before it was popularized by IBM, Microsoft and others.

Digital Research Inc

Digital/Tandem Computers/Compaq/HP


  • OSE Flexible, small footprint, high-performance RTOS for control processors
  • OSEck Small footprint, scalable, high-performance RTOS for DSPs
  • OSE ɛ Small footprint, scalable, high-performance RTOS for microcontrollers


Gould CSD (Computer System Division)

  • UTX-32, Unix based OS

Green Hills Software



  • OLERT-E; Online Executive for Real Time. Ran on Honeywell DDP-516 computers.
  • GCOS
  • Multics

Intel Corporation

  • iRMX; real-time operating system originally created to support the Intel 8080 and 8086 processor families in embedded applications.
  • ISIS-II; "Intel Systems Implementation Supervisor" was THE environment for development of software within the Intel microprocessor family in the early 1980'ies on their Intellec Microcomputer Development System and clones. ISIS-II worked with 8 inch floppy disks and had an editor, cross-assemblers, a linker, an object locator, debugger, compilers for PLM (PL/I for microprocessors of the 8080/86 family), a BASIC interpreter, etc. and allowed file management through a console.


  • OS/360 and successors on IBM mainframes
    • OS/360 (First official OS targeted for the System/360 architecture, saw customer installations of the following variations:)
      • PCP (Primary Control Program, a kernel and a ground breaking automatic space allocating file system)
      • MFT (Multi-Programming Fixed Tasks, had 15 fixed size partitions defined at boot time)
      • MVT (Multi-Programming Variable Tasks, had up to 15 partitions defined dynamically)
    • OS/VS (The official port of OS/360 targeted for the System/370 virtual memory architecture. "OS/370" is not correct name. Customer installations in the following variations:)
      • SVS (Single Virtual Storage (both VS1 & VS2 began as SVS systems))
      • OS/VS1 (Operating System/Virtual Storage 1, Virtual-memory version of OS/MFT)
      • OS/VS2 (Operating System/Virtual Storage 2, Virtual-memory version of OS/MVT)
    • MVS/SP (MVS System Product)
    • MVS/XA (MVS/SP V2. MVS supported eXtended Architecture, 31bit addressing)
    • MVS/ESA (MVS supported Enterprise System Architecture, horizontal addressing extensions: data only address spaces called Dataspaces)
    • OS/390 (Upgrade from MVS, with an additional Unix-like environment.)
    • z/OS (OS/390 supported z/Architecture, 64bit addressing.)
  • DOS/360 and successors on IBM mainframes
    • BOS/360 (Early interim version of DOS/360, briefly available at a few Alpha & Beta System 360 sites)
    • TOS/360 (Similar to BOS above and more fleeting, able to boot and run from 2x00 series tape drives)
    • DOS/360 (Disk Operating System (DOS). First commonly available OS for System/360 due to problems in the OS/360 Project. Multi-programming system with up to 3 partitions.)
      • DOS/360/RJE (DOS/360 with a control program extension that provided for the monitoring of remote job entry hardware (card reader & printer) connected by dedicated phone lines.)
    • DOS/VS (First DOS offered on System/370 systems, provided virtual storage.)
    • DOS/VSE (upgrade of DOS/VS. Still had fixed size processing partitions, but up to 14 partitions.)
    • VSE/SP (renamed from DOS/VSE.)
    • VSE/ESA (DOS/VSE extended virtual memory support to 32 bit addresses (Extended System Architecture)).
    • z/VSE (Latest version of the four decades old DOS lineage. Now supports 64 bit addresses, multiprocessing, multiprogramming, SNA, TCP/IP, and some virtual machine features in support of Linux workloads. (All DOS ref. IBM website))
  • TPF Line on IBM mainframes (real-time operating system, largely used by airlines)
  • Others on IBM mainframes
    • IBSYS (tape based operating system for IBM 7090 and IBM 7094)
    • CTSS (The Compatible Time-Sharing System developed at MIT's Computation Center)
    • RTOS/360 (Real Time Operating System, run on 5 NASA custom System/360/75s. A mash up by the Federal Systems Division of the MFT system management, PCP basic kernel and file system, with MVT task management and FSD custom real time kernel extensions and error management. The pinnacle of OS/360 developmentTemplate:Cite.)
    • MTS (Michigan Terminal System for IBM System/360)
    • TSS/360 (Time Sharing System for IBM System/360)
    • MUSIC/SP (developed by McGill University for IBM System/370)
    • IJMON (A bootable serial I/O monitor for loading programs for IBM 1400 and IBM 1800.)
  • IBM 8100
    • DPCX (Distributed Processing Control eXecutive)
    • DPPX (Distributed Processing Programming Executive)
  • IBM PC and successors on x86 architecture
    • PC DOS / IBM DOS
      • PC DOS 1.x, 2.x, 3.x (developed jointly with Microsoft)
      • IBM DOS 4.x, 5.0 (developed jointly with Microsoft)
      • PC DOS 6.x, 7, 2000
    • OS/2
      • OS/2 1.x (developed jointly with Microsoft)
      • OS/2 2.x
      • OS/2 Warp 3
      • OS/2 Warp 4
      • eComStation (Warp 4.5/Workspace on Demand, rebundled by Serenity Systems International)

International Computers Limited

  • J and MultiJob for the System 4 series mainframes
  • GEORGE 2/3/4 GEneral ORGanisational Environment, used by ICL 1900 series mainframes
  • Executive, used on the 290x range of minicomputers
  • TME, used on the ME29 minicomputer
  • ICL VME, including early variants VME/B VME/K, appearing on the ICL 2900 Series and Series 39 mainframes

LynuxWorks (originally Lynx Real-time Systems)

Micrium Inc.

  • MicroC/OS-II (Small pre-emptive priority based multi-tasking kernel)


MontaVista Software

  • MontaVista Linux
    • MontaVista Professional Edition
    • MontaVista Carrier Grade Edition
    • MontaVista Mobilinux

NCR Corporation

  • TMX - Transaction Management eXecutive


  • NetWare network operating system providing high-performance network services. Has been superseded by Open Enterprise Server line, which can be based on NetWare or Linux to provide the same set of services.
  • Open Enterprise Server, the successor to NetWare.
  • OpenSUSE, SUSE operating system (formerly SuSe and s.u.s.e)

Quadros Systems

  • RTXC Quadros RTOS proprietary C-based RTOS used in embedded systems


  • BEST - Business Executive System for Timesharing


  • TSOS, first OS supporting virtual addressing of the main storage and support for both timeshare and batch interface


SCO / The SCO Group[1]

  • Xenix, Unix System III based distribution for the Intel 8086/8088 architecture
    • Xenix 286, Unix System V Release 2 based distribution for the Intel 80286 architecture
    • Xenix 386, Unix System V Release 2 based distribution for the Intel 80386 architecture
  • SCO Unix, SCO UNIX System V/386 was the first volume commercial product licensed by AT&T to use the UNIX System trademark (1989). Derived from AT&T System V Release 3.2 with an infusion of Xenix device drivers and utilities plus most of the SVR4 features
    • SCO Open Desktop, the first 32-bit graphical user interface for UNIX Systems running on Intel processor-based computers. Based on SCO Unix
  • SCO OpenServer 5, AT&T UNIX System V Release 3 based
  • SCO OpenServer 6, SVR5 (UnixWare 7) based kernel with SCO OpenServer 5 application and binary compatibility, system administration, and user environments
  • UnixWare
    • UnixWare 2.x, based on AT&T System V Release 4.2MP
    • UnixWare 7, UnixWare 2 kernel plus parts of 3.2v5 (UnixWare 2 + OpenServer 5 = UnixWare 7). Referred to by SCO as SVR5


  • Scos 1
    • Scos 1.2
    • Scos 1.5
  • Scos 2.0
    • Scos 2.5
  • Scos 3
  • Scos 4
  • Scos 5
  • Scos 6 (Latest Stable Version)

SDS (Scientific Data Systems)

  • CP Control Program. SDS later acquired by Xerox, then Honeywell.

SEL (Systems Engineering Laboratories)

  • Real Time Monitor (RTM)
  • MPX-32


  • PikeOS is a certified real time operating system for safety and security critical embedded systems


TRON Project

Unicoi Systems

  • Fusion RTOS highly prolific, license free Real-time operating system.
  • DSPOS was the original project which would become the royalty free Fusion RTOS.


UNIVAC (later Unisys)


Wang Laboratories

  • 2200T Wang BASIC based system for the multi-user, 2200T systems. Products included a system called Personal Computer before the term was made more popular with IBM products.
  • 2200VP/MVP Wang BASIC based system for the higher performance, 2200VP/MVP multi-user systems. Contained sophisticated micro-code programming for high performance operation.
  • WPS Wang Word Processing System. Micro-code based system. Very clever and productive system developed by Harold Kaplow while at Wang. Eventually phased out by the PC and Word Perfect.
  • OIS Wang Office Information System. Successor to the WPS. Combined the WPS and VP/MVP systems. Harold Kaplow was its principal architect. Eventually phased out by the 2200VS.
  • 2200VS IBM assembler instruction set microcode emulation. Supported the Wang 2200VS high-performance, multi-user systems. Designed to be a COBOL developers dream machine. Included some of the OIS operating system code. Eventually phased out by the UNIX operating system.

Wind River Systems

  • VxWorks Small footprint, scalable, high-performance RTO



Non-standard language-based

Other proprietary non-Unix-like

Other proprietary Unix-like and POSIX-compliant



Research Unix-like and other POSIX-compliant

Free/Open source Unix-like

  • BSD (Berkeley Software Distribution, a variant of Unix for DEC VAX hardware)
    • FreeBSD (one of the outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
    • NetBSD (one of the outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
  • GNU
  • μnix (concept unix-like operating system for ATMEL microcontrollers)
  • Linux (GNU Free/Open Source Operating System Software combined with the Linux kernel)

Other Unix-like

  • TUNIS (University of Toronto)


Research non-Unix-like

  • Amoeba (research OS by Andrew S. Tanenbaum)
  • Cambridge CAP computer operating system demonstrated the use of security capabilities, both in hardware and software, also a useful fileserver. Written in ALGOL 68C.
  • Croquet
  • House Haskell User's Operating System and Environment, research OS written in Haskell and C.
  • ILIOS Research OS designed for routing
  • EROS microkernel, capability-based
  • L4 Second generation microkernel
  • Mach (from OS kernel research at Carnegie Mellon University; see NeXTSTEP)
  • MONADS, capability-based OS designed to support the MONADS hardware projects
    • SPEEDOS (Secure Persistent Execution Environment for Distributed Object Systems) builds on MONADS ideas
  • Nemesis Cambridge University research OS - detailed quality of service abilities.
  • Spring (research OS from Sun Microsystems)
  • V from Stanford, early 1980s [2]
  • FreeNOS, a microkernel educational operating system

Free/Open source non-Unix-like

  • FullPliant (programming language-based)
  • FreeDOS (open source DOS variant)
  • FreeVMS (open source VMS variant)
  • Haiku (open source inspired by BeOS, under development)
  • Kinetic (written in Haskell)
  • MonaOS (written in C++)
  • ReactOS (Windows NT-compatible OS, in early development since 2001)
  • osFree (open source OS/2 implementation)
  • OZONE (object-oriented)
  • MustiOS (32-bits operating system)

Disk Operating Systems

Main article: DOS


Web operating systems

Main article: Web operating system

Generic/commodity and other

For Elektronika BK

  • AO-DOS
  • DOSB10
  • DX-DOS
  • FA-DOS
  • HC-DOS
  • KMON
  • MicroDOS
  • MK-DOS
  • NORD
  • PascalDOS
  • RT-11
    • ROM embedded
    • RT-11SJ
    • OS BK-11 (RT-11 version)
  • Turbo-DOS


  • AROS (AROS Research Operating System, formerly known as Amiga Research Operating System)
  • AtheOS (branched to become Syllable Desktop)
  • DexOS, (Games console OS, for x86, written in FASM)
  • EROS (Extremely Reliable Operating System)
  • FAMOS (Foremost Advanced Memory Operating System)
  • HelenOS, based on a preemptible microkernel design
  • LoseThos, the stated goal is "programming as entertainment" - oriented toward video games
  • LSE/OS
  • MenuetOS (extremely compact OS with GUI, written entirely in FASM assembly language)
  • Möbius (an open-source operating system for the IA-32 platform (Intel i386 and compatibles) [4])
  • MikeOS
  • NewOS
  • Unison RTOS FREE
  • Visopsys
  • TajOS
  • eSTORM


Personal digital assistants (PDAs)

Digital media players


  • Robotic Operating System
  • Dave's Robotic Operating System [5]



Other embedded


LEGO Mindstorms

Other capability-based

  • KeyKOS nanokernel
  • MONADS, designed to support the MONADS hardware projects.
    • SPEEDOS builds on MONADS ideas
  • V from Stanford, early 1980s [2]

See also

Category links


External links

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