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.
Unics ("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)
RDOS Real-time Disk Operating System, with variants: RTOS and DOS (not related to PC DOS, MS-DOS etc.)
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.
Google 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.
Chromium OS is an open source operating system development version of Google Chrome OS. Both operating systems are based on the Linux kernel.
Android is an operating system for mobile devices. It consists of Dalvik (userland) with Linux (kernel), with its Linux kernel modified to add drivers for mobile device hardware and to remove unused Vanilla Linux drivers.
es is a computer operating system developed originally by Nintendo and since 2008 by Google. It is open source and runs natively on x86 platforms.
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 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 PLM (PL/I for microprocessors of the 8080/86 family), a BASIC interpreter, etc. and allowed file management through a console.
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 (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/370virtual 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)
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.
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
UniFLEX (Unix-like OS from TSC for DMA-capable, extended addresses, Motorola 6809 based computers; e.g. SWTPC, GIMIX, …)
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.)
OpenSolaris, contains original Unix (SVR4) code. Now discontinued by Oracle in favor of Solaris 11 Express
OpenIndiana, aims to continue development and distribution of OpenSolaris operating system. Operates under the Illumos Foundation. Uses the Illumos kernel, which is a derivative of OS/Net, which is basically a Solaris/OpenSolaris kernel with the bulk of the drivers, core libraries, and basic utilities.
Nexenta OS, based on the OpenSolaris kernel with Ubuntu packages
Jaris OS, based on OpenSolaris with support for Japanese
RTEMS (Real-Time Executive for Multiprocessor Systems)