Small embedded operating system that runs on Apple Computer's "Macintosh Coprocessor Platform", an expansion card for the Apple Macintosh.

Apple, USA

UNIX System V with BSD extensions. Last version in 1996.

Apple, USA

Real-time kernel.

Code Time, USA

Unix-like real-time operating system. Developed for the ABC 1600 computer from Luxor.

Dataindustrier, Sweden

Network OS kernel for the PERQ workstation.

Carnegie-Mellon University, USA

Discontinued open-source software based operating system, once referred to as a "next-generation version of the Palm OS," for mobile devices developed and marketed by Access Co.

Access, Japan

32bit multitasking operating system for IA32 developed for experimental and exploration purpose.

Discontinued computer operating system used in the Acorn BBC computer range.

Acorn Computers, UK

Advanced Comprehensive Operating System-2. Operating system for small computer systems.

NEC, Japan

Operating system for ACOS System model 410.

Operating system for the ACOS System 3300 series, which fully adopted a CMOS full-customer LSI.

ACOS extended processor. Operating system designed for compact mainframes.

ACOS millennium processor. Operating system designed for NEC’s small mainframes.

Advanced Comprehensive Operating System-4. Small-to-medium machines.

NEC, Japan

Operating system for large and super-large machines.

ACOS Advanced Virtual Processor.

Multi Virtual Processor/eXtended Environment.

ACOS Advanced Virtual Processor eXtended Release.

ACOS eXtended multi Virtual Processor.

ACOS extended multi virtual processor, parallel extended. operating system intended for NEC’s mid-range and large mainframes.

ACOS new parallel extended.

ACOS internet − parallel extended. Was an operating system designed for NEC’s mid-range and large mainframes.

Large general-purpose operating system that realized multi-dimensional processing.

NEC, Toshiba, Japan

ACOS Multiple Virtual eXtended. Operating system for large to ultra-large machines.

ACOS Multiple Virtual eXtended II.

ACOS new virtual extended.

ACOS parallel extended.

Airline Control Program. In contrast to previous airline transaction processing systems, the most notable aspect of ACP is that it was designed to run on most models of the IBM System/360 mainframe computer family.

IBM, USA

Project to create a new fully distributed OS, written mostly in Ada.

ADMIRAL Master Monitor. Operating system for the Honeywell 800/1800.

Honeywell, USA

Soviet MS-DOS equivalent.

Russia

Discontinued operating system used by the Apollo/Domain line of workstations.

Apollo Computer, USA

Analog to Apple-DOS fopr russian MS-DOS computers.

Minradioprom, Russia

Agent-based Distributed Operating System for Mobile Networks.

Larry Chen, USA

Small OS kernel for i386, supporting 32-bit protected memory mode, paging, hardware switched tasks, memory tests (RW, ECC, address patterns), PCI bus, devices, PCI IRQ routing, RT timers and network protocols.

Operating System for Ubiquiti M Series Products.

Ubiquiti Networks, USA

Time-sharing operating system with batch and multi-access.

Russia

Advanced Interactive eXecutive. System V Unix version. Series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms.

IBM, USA

IBM's fourth attempt to offer Unix-like functionality for their mainframe line.

Locus Computing, USA

Replacement of sys AIX/370 which was based on OSF/1.

IBM, USA

Was a project to determine if AOP can be used to improve OS modularity, and thereby reduce complexity and fragility associated with system implementation.

Yvonne Coady, Gregor Kiczales, Ida Chan, Greg Smolyn, International

Disk operating system.

Russia

Open-source implementation of operating system (OS) for Internet of Things (IoT).

Alibaba, China

Was a split from Freedows, its goal was to implement an OS based on isolated components, described with the Corba IDL and communicating through a System ORB.

Operating system developed by Allied Telesis, used on its high-end enterprise network switches.

Allied Telesis (a.k.a. Allied Telesyn), USA

MS-DOS-like Soviet operating system.

Russia

Early disk operating system for the Altair 8800 machine.

MITS, USA

Alto operating system.

Xerox, USA

Just another view on how should OS be designed.

Dozz, Finland

Real time, minimum kernel operating system for doing DSP work and amateur radio digital modes.

Altos Multiuser Executive. Support up to four simultaneous users.

Altos, USA

Aka Amix. Amiga ports of Unix System V release 3.2 with Amiga A2500UX and SVR4 with Amiga A3000UX.

Commodore-Amiga, Canada

Latest stable release.

Basic operating system for Amiga computers. Derived from TRIPOS.

Commodore-Amiga, Canada

Family of proprietary native operating systems of the Amiga and AmigaOne personal computers.

Commodore-Amiga, Canada

Small, user-friendly OS for the Hewlett-Packard 300.

Hewlett-Packard, USA

Microkernel OS with multiple servers, allowing parallel (transparent to the user) execution, resource sharing, and more; the reference among distributed Oses. Based partly on UNIX.

A Modular Operating Kernel for the CRAY-1 at the Institute for Defense Analysis. A modular timesharing system providing files, directories, processes, and pipes.

USA

Alpha Micro Operating System. Multiuser, multiprocessing OS for the 68000 family of microprocessors.

Alpha Microsystems, USA

AMOS for 68000 machines.

Advanced Monitor System. A single user interactive disk or tape OS for the PDP-9 & PDP-15.

DEC, USA

Operating system for DEC minicomputers.

ITC, Romania

AMStrad Disk Operating System. Disk operating system for the 8-bit Amstrad CPC Computer (and various clones).

UK

Real-time operating system.

Kadak, USA

Russian operating system for Electronika BK-0010, Electronika BK-0011 and Electronika BK-0011M series computers.

Alexey Nadezhin and Sergey Kamnev, Russia

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.

Google, USA

Code name "Ice Cream Sandwich".

Unofficial initiative to port Google's Android mobile operating system to run on devices powered by AMD and Intel x86 processors, rather than RISC-based ARM chips.

Google, USA

Linux distribution for a variety of embedded devices. The distribution is the result of work by developers from the OpenZaurus, OpenEmbedded, and OpenSIMpad projects.

Live CD operating system based on OpenBSD 3.8 with strong encryption and anonymization tools. The goal of the project was to provide secure, anonymous web browsing access to everyday users.

All-round Operating System. The first OS for Office computers.

Mitusbishi, Japan

Advanced Operating System for Data General Eclipse and MV series.

Data General, USA

BSD Unix version, not related to Data General AOS.

IBM, USA

Burroughs, USA

Operating System for 32-bit (MV series) Eclipse computers.

Data General, USA

Modular real-time operating system for connected Internet of things.

Reflexive Object Oriented OS.

Sony, Japan

Project is based on a microkernel, for which has been started a project apart, Gemini Nucleus, whose inspiration sources are L4, Aegis and EROS.

Guido de Jong, J. Spencer Seidel, Netherlands

Operating system for Apple III.

Apple, USA

Operating system for Apple Macintosh.

Apple, USA

Operating system for Apple MessagePad.

Apple, USA

Operating system for Apple Network Server computers.

Apple, USA

Operating system for Apple II.

Apple, USA

Sophisticated Operating System. Primary operating system developed for the Apple III computer.

Apple, USA

Digital media player and microconsole.

Apple, USA

Operating system for the Apple Watch.

Apple, USA

Basic Operating System for Apple II Computers. It was superseded by ProDOS in 1983.

Apple, USA

Distributed operating system.

University of Wisconsin, USA

Industry's First Internet-Scale, Independent Network Operating System.

Arrcus, USA

Operating system which dynamically compiles high-level languages to machine code as needed.

Alaric B. Snell, UK

ARGonne Operating System.

Argonne National Laboratory, USA

QDOS adaptation for Thor computers.

UK

Distributed programming system featuring resilient objects.

MIT, USA

Object-oriented programming system, implemented entirely in C++, that provides a set of tools for the construction of fault-tolerant distributed applications.

University of Newcastle upon Tyne, UK

Platform and operating system for internet-connected devices based on 32-bit ARM Cortex-M microcontrollers.

ARM, UK

Accelerated Realtime Multitasking Operating System. Full-featured, prioritized, multitasking, message based, real-time operating system.

National Politchnical University of Armenia, Armenia

AROS Research Operating System, formerly known as Amiga Research Operating System. Free open source AmigaOS like OS.

Operating system for the ARPANET.

Lawrence Roberts, B. Wessler, USA

Original version of RISCO OS.

Acorn Computers, UK

First version of Arthur. Became RISC OS in 1987.

Became RISC OS 2.

Optimised distributed operating system with all facilities for real-time multiprocessor and real-time network configurations including Internet support and advanced development tools.

Locamation, Netherlands

ARM Real Time Operating System. Designed to allow control of embedded devices in real time.

Unreleased Mach-like operating system written in Modula-2+.

Acorn Computers, UK

Application System/400. Originally named OS/400.

IBM, USA

Army Secure Operating System. TCSEC A1-class secure, real-time OS for Ada applications.

US Army, USA

Russian Linux-based computer operating system developed to meet the needs of the Russian army, other armed forces and intelligence agencies.

RusBitTech, Russia

Disk operating system used with the Atari 8-bit family of computers.

Atari, USA

Multitasking version of TOS. Predecessor of MiNT.

Atari, USA

The Operating System. Also Tramiel Operating System, from Jack Tramiel, owner of Atari Corp. at the time. The operating system of the Atari ST range of computers.

Atari, USA

Primarily for 68030 TT.

Update for Falcon 030 machines only.

Discontinued free and open source operating system for x86-based computers. It was initially intended as an AmigaOS clone, but that objective was later abandoned. Branched to become Syllable Desktop.

Kurt Skauen, Denmark

Supervisor Program for the first computer designed to use an operating system. Introduced system calls and virtual storage. Multiprogramming OS.

Manchester University, UK

Minimalist OS fitting on a boot sector of a floppy.

Free, lightweight, portable, real-time scheduler for embedded systems.

Multi-user, multi-tasking and multilingual C# operating system using Cosmos and IL2CPU.

Genesi, USA

Unix III version. Reliable Operating System for the fault-tolerant minicomputer AURAGEN System 4000.

Auragen, USA

A VIrtual Operating System. The idea behind this project is to have a networked system that can run multiple processes and be all things to all men.

RTOS based on the segmented RTOS architecture. AVIX supports many of the most advanced micro controllers and fully exploits their capabilities.

AVIX-RT, USA

Advanced Virtual Machine/Extended Facilities. Was an operating system that controlled Fujitsu’s virtual computer (VM: Virtual Machine) system.

Fujitsu, Japan

Advanced Virtual Machine/Extended Architecture.

Fujitsu, Japan

Advanced Versatile Extended. Operating system.

NEC, Japan