This is a list of operating systems. Computer 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. Criteria for inclusion is notability, as shown either through an existing Wikipedia article or citation to a reliable source.
magnussoft ZETA (based on BeOS r5.1d0 source code, developed by yellowTAB)
Unix ("Ken's new system," for its creator (Ken Thompson), officially Unics and then Unix, the prototypic operating system created in Bell Labs in 1969 that formed the basis for the Unix family of operating systems)
UNIX Time-Sharing System v1
UNIX Time-Sharing System v2
UNIX Time-Sharing System v3
UNIX Time-Sharing System v4
UNIX Time-Sharing System v5
UNIX Time-Sharing System v6
UNIX Time-Sharing System v7 (It is from Version 7 Unix (and, to an extent, its descendants listed below) that almost all Unix-based and Unix-like operating systems descend.)
Unix System III
Unix System IV
Unix System V
Unix System V Releases 2.0, 3.0, 3.2, 4.0, and 4.2
Chromium OS is an open source operating system development version of Chrome OS. Both operating systems are based on the Linux kernel.
Chrome OS is designed to work exclusively with web applications. Announced on July 7, 2009, Chrome OS is currently publicly available and was released summer 2011. The Chrome OS source code was released on November 19, 2009, under the BSD license as Chromium OS.
Container-Optimized OS (COS) is an operating system that is optimized for running Docker containers, based on Chromium OS.
Android is an operating system for mobile devices. It consists of Android Runtime (userland) with Linux (kernel), with its Linux kernel modified to add drivers for mobile device hardware and to remove unused Vanilla Linux drivers.
gLinux, a Linux distribution that Google uses internally
Fuchsia is a capability-based, real-time, operating system (RTOS) scalable to universal devices, in early development, from the tiniest embedded hardware, wristwatches, tablets to the largest personal computers. Unlike Chrome OS and Android, it is not based on the Linux kernel, but instead began on a new microkernel called "Zircon", derived from "Little Kernel".
Vulcan O/S – Proprietary O/S for Harris' Computer Systems (HCX)
Harris UNIX – Proprietary UNIX based OS for Harris' Computers (MCX)
Heathkit, Zenith Data Systems
HDOS – ran on the H8 and Heath/Zenith Z-89 series
HT-11 – a modified version of RT-11 that ran on the Heathkit H11
HP Multi-Programming Executive (MPE, MPE/XL, and MPE/iX) – runs on HP 3000 and HP e3000 mini-computers
HP-UX – runs on HP9000 and Itanium servers (from small to mainframe-class computers)
NonStop OS – runs on HP's NonStop line of Itanium servers
iRMX – real-time operating system originally created to support the Intel 8080 and 8086 processor families in embedded applications.
ISIS, ISIS-II – "Intel Systems Implementation Supervisor" was an environment for development of software within the Intel microprocessor family in the early 1980s 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 PL/M, a BASIC interpreter, etc. and allowed file management through a console.
OS/360 (first official OS targeted for the System/360 architecture)
PCP (Primary Control Program, a kernel and a ground breaking automatic space allocating file system)
MFT (original Multi-programming with a Fixed number of Tasks, replaced by MFT II)
MFT II (Multi-Programming with a Fixed number of Tasks, had up to 15 fixed size application partitions, plus partitions for system tasks, initially defined at boot time but redefinable by operator command)
MVT (Multi-Programming Variable Tasks, had up to 15 application regions defined dynamically, plus additional regions for system tasks)
OS/VS (port of OS/360 targeted for the System/370 virtual memory architecture, "OS/370" is not correct name for OS/VS1 and OS/VS2, but rather refers to OS/VS2 MVS and MVS/SP Version 1), 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 MFT II)
OS/VS2 (Operating System/Virtual Storage 2, Virtual-memory version of OS/MVT but without multiprocessing support)
OS/VS2 R2 (called Multiple Virtual Storage, MVS, eliminated most need for VS1)
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.
Novell "SuperNOS" – a never released merge of NetWare and UnixWare
Open Enterprise Server – the successor to NetWare
RTXC Quadros RTOS – proprietary C-based RTOS used in embedded systems
Time Sharing Operating System (TSOS) – first OS supporting virtual addressing of the main storage and support for both timeshare and batch interface
DSPnano RTOS – 8/16 Bit Ultra Tiny Embedded Linux Compatible RTOS
Tizen is an operating system based on the Linux kernel, a project within the Linux Foundation and is governed by a Technical Steering Group (TSG) while controlled by Samsung and backed by Intel. Tizen works on a wide range of Samsung devices including smartphones, tablets, smart TVs, PCs and wearable.
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 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
Scientific Data Systems (SDS)
Berkeley Timesharing System for the SDS 940
PikeOS – a certified real time operating system for safety and security critical embedded systems
TRSDOS – A floppy-disk-oriented OS supplied by Tandy/Radio Shack for their TRS-80 Z80-based line of personal computers. Eventually renamed as LS-DOS or LDOS.
Color BASIC – A ROM-based OS created by Microsoft for the TRS-80 Color Computer.
NewDos/80 – A third-party OS for Tandy's TRS-80 personal computers.
DeskMate – Operating system created by Tandy Corporation and introduced with the Tandy 1000 computer.
TCSC (later NCSC)
Edos – enhanced version of IBM's DOS/360 (and later DOS/VS and DOS/VSE) operating system for System/360 and System/370 IBM mainframes
TI-RTOS Kernel – Real-time operating system for TI's embedded devices.
QNX (POSIX, microkernel OS; usually a real time embedded OS)
Rhapsody (an early form of Mac OS X)
RISC iX – derived from BSD 4.3, by Acorn computers, for their ARM family of machines
RISC/os (a port by MIPS Technologies of 4.3BSD for its MIPS-based computers)
SCO UNIX (from SCO, bought by Caldera who renamed themselves SCO Group)
SINIX (a port by SNI of Unix to the MIPS architecture)
Solaris (from Sun, bought by Oracle; a System V-based replacement for SunOS)
SunOS (BSD-based Unix system used on early Sun hardware)
SUPER-UX (a port of System V Release 4.2MP with features adopted from BSD and Linux for NEC SX architecture supercomputers)
System V (a release of AT&T Unix, 'SVR4' was the 4th minor release)
System V/AT, 386 (The first version of AT&T System V UNIX on the IBM 286 and 386 PCs, ported and sold by Microport)
Trusted Solaris (Solaris with kernel and other enhancements to support multilevel security)
UniFLEX (Unix-like OS from TSC for DMA-capable, extended addresses, Motorola 6809 based computers; e.g. SWTPC, GIMIX and others)
Unicos (the version of Unix designed for Cray Supercomputers, mainly geared to vector calculations)
UTX-32 (Developed by Gould CSD (Computer System Division), a Unix-based OS that included both BSD and System V characteristics. It was one of the first Unix based systems to receive NSA's C2 security level certification.)
Zenix, Zenith corporations Unix (a popular USA electronics maker at the time)
Unix or Unix-like
MINIX (study OS developed by Andrew S. Tanenbaum in the Netherlands)
BSD (Berkeley Software Distribution, a variant of Unix for DECVAX hardware)
FreeBSD (one of the outgrowths of UC Regents' abandonment of CSRG's 'BSD Unix')
illumos, contains original Unix (SVR4) code derived from the OpenSolaris (discontinued by Oracle in favor of Solaris 11 Express)
OpenIndiana, operates under the illumos Foundation. Uses the illumos kernel, which is a derivative of OS/Net, which is basically an OpenSolaris/Solaris kernel with the bulk of the drivers, core libraries, and basic utilities.
Nexenta OS, based on the illumos kernel with Ubuntu packages
SmartOS, an illumos distribution for cloud computing with Kernel-based Virtual Machine integration.
RTEMS (Real-Time Executive for Multiprocessor Systems)
Plurix (or Tropix) (By Federal University of Rio de Janeiro - UFRJ)
TUNIS (University of Toronto)
Cosmos – written in C#
FreeDOS – open source DOS variant
Genode – operating system framework for microkernels (written in C++)
Ghost OS – written in Assembly, C/C++
Haiku (open source inspired by BeOS, under development)
ITS – written by MIT students (for the PDP-6 and PDP-10) (written in MIDAS)
THE multiprogramming system – by Dijkstra in 1968, at the Eindhoven University of Technology in the Netherlands, introduced the first form of software-based memory segmentation, freeing programmers from being forced to use actual physical locations
Thoth – realtime, multiprocess message-passing system developed at the University of Waterloo.
^"Despite its name suggesting some similarity to Unix, Xinu is a different type of operating system, written with no knowledge of the Unix source code, or compatibility goals. It uses different abstractions, and system calls, some with names matching those of Unix, but different semantics."
Garfinkel, Simson; Spafford, Gene; Schwartz, Alan (2003). Practical UNIX and Internet Security. O'Reilly. p. 19.