List of operating systems

This is a **list of operating systems** for computers.

## The first operating systems
*CTSS (The Compatible TimeShare System, made at MIT by Corbato and others)
*Incompatible Timesharing System (The Incompatible Timeshare System, made at MIT)
*Multics (project by Bell Labs, GE, and MIT)
*Master programme for Leo Computers, Leo III in 1962
*THE operating system (by Dijkstra and others)

### The first proprietary computer operating systems
*Apple Computer (first version was firmware with Integer BASIC; later versions had Microsoft BASIC)
*Business Operating System (BOS) - cross platform, text-based
*Commodore PET, Commodore 64, and Commodore VIC-20,
*First IBM-PC had 3 OSes to start, UCSD P-system, CPM-86, PC-DOS
*Flex (by Technical Systems Consultants for Motorola 6800 based computers: 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)
*Sinclair Micro and QX, etc.
*TRS-DOS, ROM OS's (largely Microsoft BASIC implementations with file system extensions)
*TI99-4

### Unix-like and other POSIX-ready systems
*AIX (Unix from IBM)
*Amoeba (research OS by Andrew S. Tanenbaum)
*AtheOS (continued with the Syllable code-fork)
*A/UX (Unix Apple OS from start of 1990s)
*BSD (Berkeley Software Distribution, a type of Unix)
*Cromix (Unix-emulating OS from Cromemco)
*Coherent (Unix-emulating OS from Mark Williams Co.)
*DNIX
*Digital UNIX (later, HP's Tru64 for Digital's AXP 64-bit computers)
*FreeBSD (Version of abandoned BSD with free source code)
*GNU/Hurd
*Haiku (operating system)
*HP-UX from HP
*Idris from Whitesmiths
*IRIX from SGI
*LainOS (FreeBSD project, a tried version of "Navi" GUI from *Serial Experiments Lain*)
*Linux (free Unix-like kernel)
*Minix (educational OS by Andrew S. Tanenbaum in the Netherlands)
*NetBSD (post-CSRG open source type of BSD)
*NeXTSTEP (foundation for OS X)
*OS-9 (not to be confused with Mac OS 9)
*OS-9/68k
*OS-9000 (OS-9 written in C)
*OS/360
*OSF/1
*OS X from Apple Inc.
*OpenBSD (post-CSRG open source type of BSD)
*OPENSTEP NeXTSTEP on Intel x86, HP PA-RISC, and different architectures.
*Plan 9 (by Bell Labs)
*QNX (POSIX, microkernel OS)
*Rhapsody
*RiscOS
*SCO UNIX (from SCO, purchased by Caldera)
*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 in 1970 first by Ken Thompson)
*UNIflex (Unix emulating OS by TSC)
*Ultrix (DEC's first version of Unix for VAX, PDP-11, MIPS, and Decstation computers)
*UniCOS from Cray
*Xenix (Microsoft's version of Unix)
*z/OS (IBM mainframe OS)

### Generic/commodity, non-UNIX, and other
*AOS, now called Bluebottle(update to Oberon operating system)
*AROS (Amiga Research Operating System)
*Bluebottle (see AOS)
*BS2000 by Siemens AG
*Control Program/Monitor-80 (CPM operating system)
*CP/M-86 (by Digital Research)
*DESQView (windowing GUI for MS-DOS,1985)
*DR-DOS (MS-DOS compatible OS from Digital Research)
*FLEX9 (by TSC)
*FreeDOS (open source, free MS-DOS alternative)
*GEM (GUI for MS-DOS by Digital Research)
*GEOS
*MS-DOS (Microsoft purchased from Seattle Computer)
*MorphOS (by Genesi)
*NetWare (by Novell)
*NeXTStep (Foundation for OS X)
*PC-DOS (IBM's version of MS-DOS)
*Pick
*Plan 9, Inferno (networked OS by Bell Labs)
*Primos by Prime Computer
*Mach (kernel by CMU, used in NeXTStep and OS X)
*MP/M-80 (by Digital Research)
*NewOS
*Oberon operating system (developed at ETH-Zürich by Niklaus Wirth)
*OS/2 Windows/MS-DOS compatible operating system made in a Microsoft and IBM project, but later Microsoft stopped when they wanted to work on Windows NT more; which was better than early Windows versions and MS-DOS.
*OS-9 (Unix emulating OS from Microware)
*OS-9/68k (Unix emulating OS from Microware)
*OS-9000 (portable Unix emulating OS from Microware)
*SSB-DOS (by TSC for Smoke Signal Broadcasting; a variant of FLEX)
*TripOS
*TUNES
*QDOS (made at Seattle Computer Products by Tim Paterson for new Intel 808x CPUs. Given to Microsoft—soon became MS-DOS)
*UCSD P-system (OS by a student project at the University of California, San Diego; directed by Prof Ken Bowles)
*VisiOn (first GUI for early PC machines, not successful)
*Visopsys (hobby OS for PCs)
*VME by International Computers Limited (ICL)
*Randolf by United Computer inc,
*Vision (first GUI for early PC machines, not successful, by Microware)

## Hobby OS
Operating systems written for a hobby.
*ReactOS (an open source OS that runs Windows NT applications natively)
*Panalix
*MenuetOS
*SkyOS

## Proprietary
### Acorn
*Arthur
*ARX
*RISC OS (was later open sourced under a fully free/open source license)
*RISCiX

### Amiga
*AmigaOS
*AmigaOS 4

### Atari ST
*MultiTOS
*MiNT
*TOS

### Apple
*Apple DOS
*A/UX
*Darwin
*GS/OS
*iOS
*Macintosh/Mac OS classic
*macOS
*Newton OS
*ProDOS

### Be Incorporated
*BeOS
*BeIA
*Zeta

### Digital/Compaq/HP
*AIS
*ITS (for the PDP-6 and PDP-10)
*OS-8
*RSTS/E (ran on several machines, chiefly PDP-11s)
*RSX-11 (multi-user, multitasking OS for PDP-11s)
*RT-11 (single user OS for PDP-11)
*TENEX (from BBN)
*TOPS-10 (for the PDP-10)
*TOPS-20 (for the PDP-10)
*VMS (by DEC for the VAX mini-computer type; later renamed OpenVMS)
*WAITS

### IBM
*AIX (a version of Unix)
*ALCS
*Basic Operating System (first system released for the System 360, as an interim)
*DOS/VSE
*MFT (later called OV/VS1)
*MVS (latest variant of MVT)
*MVT (later called OV/VS2)
*OS/2
*OS/360 (first OS planned for the System 360 architecture)
*OS/390
*OS/400
*PC-DOS (IBM's version of DOS)
*SVS
*TPF
*VM/CMS
*z/OS

### Microsoft
*Xenix
*MS-DOS
*Microsoft Windows
**Windows 1.0x (Mostly text interface organised into windows, because graphical hardware was  at the time)
**Windows 2.X
**Windows 3.X
**Windows NT
**Windows NT 4.0
**Windows 9x
**Windows Me
**Windows 2000
**Windows XP (based on code of Windows 2000, was first "non-business" version of Windows NT)
**Windows Server 2003
**Windows Vista
**Windows Server 2008
**Windows 7
**Windows Server 2008 R2
**Windows 8
**Windows Server 2012
**Windows 8.1
**Windows Server 2012 R2
**Windows 10
**Windows Server 2016
**Windows Server 2019
**Windows 11
*Xenix

### Personal digital assistants (PDAs)
*EPOC, today is named Symbian OS
*iOS from Apple
*Newton OS from Apple, for  Apple Newton MessagePad
*Palm OS from Palm Inc
*Pocket PC from Microsoft
*Windows CE (Windows Compact Edition, from Microsoft)

### Microcontroller, embedded
Little operating systems that run on small devices.
*Contiki
*INTEGRITY
*ITRON
*Nucleus RTOS
*OSEK
*QNX
*ThreadX
*TRON OS by Ken Sakamura
*VxWorks
*µCLinux
*eCos

## Fictional operating systems
Operating systems that have only appeared in fiction or as jokes.
*Lcars - From Star Trek
*ALTIMIT OS - From .hack
*Digitronix - From The Hacker Files
*Hyper OS - From the movie Patlabor
*Penix - Funny word formed from Microsoft Xenix and a not great word
*Wheatonix - April fool's joke.
*GLADOS - **G**enetic **L**ifeform **a**nd **D**isk **O**perating **S**ystem
*Lex/OS - From DCEU/DCU

## Related pages
*Computer software
*Disk operating system