See Berkeley Software Distribution (BSD).

U.C. Berkeley, USA

Timesharing operating system.

Hewlett-Packard, USA

Timesharing operating system.

Hewlett-Packard, USA

Disc operating system for HP-2100.

Hewlett-Packard, USA

See Berkeley Software Distribution.

U.C. Berkeley, USA

Formerly known as SPINE. Distributed, reflexive, component-based, adaptable OS.

University of Illinois, Universidad Carlos III - Madrid, USA, Spain

Sometimes called "Jolix". Discontinued free Unix-like operating system.

William Jolitz, Lynne Jolitz, USA

Discontinued operating system released by DEC for their PDP-8 line of mini-computers.

DEC, USA

Developed at Seattle Computer Products by Tim Paterson for the new Intel 808x CPUs; licensed to Microsoft, became PC DOS/MS-DOS. Also known by its working title QDOS.)

Seattle Computer Products, USA

Fork of Plan 9. Started to remedy a perceived lack of devoted development resources inside Bell Labs, and has accumulated various fixes and improvements.

Bell Labs, 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

Advanced Versatile Extended. Operating system.

NEC, Japan

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

ACOS extended processor. Operating system designed for compact mainframes.

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

NEC, Japan

ACOS Advanced Virtual Processor.

ACOS Advanced Virtual Processor eXtended Release.

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

Operating system for large and super-large machines.

Multi Virtual Processor/eXtended Environment.

ACOS new parallel extended.

ACOS eXtended multi Virtual Processor.

ACOS extended multi virtual processor, parallel extended. operating system intended 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

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.

Disk operating system.

Russia

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

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

Data General, USA

Burroughs, 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

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

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

Operating System for NCR Century series computers.

NCR, USA

Operating System for NCR Century series computers.

NCR, USA

Operating System for NCR Century series computers.

NCR, USA

Operating System for NCR Century series computers.

NCR, USA

Multiprogramming operating system.

Burroughs, USA

Basic Abstraction Block. 50Kb IA-32 microkernel for DOS. It manages the x86 hardware interaction in a manner similar to Windows' HAL. BABy can be used to provide PMode services to our shareware multiuser O/S, VMiX x86 (listed velow). Distribution includes binaries, sources, makefiles, samples and API docs.

Operating system for mobile devices such as smartphones and tablet computers.

Samsung Electronics, Korea

Real-time operating system developed for a MIPS (Baget-MIPS variant) and Intel BSPs (x86 architecture).

Russian Academy of Sciences, Russia

Network operating system for computers running AT&T's UNIX System V.

Banyan Systems, USA

Exokernel-based single address space operating system.

Return Infinity, USA

Memory-based real-time executive for the IBM 1710.

IBM, USA

Realtime OS for the Phillips P-855 and P-860.

USA

Operating system for the Soviet personal computers BK-0010.

Russia

Also known simply as DOS-11 was the first operating system to run on the Digital PDP-11 minicomputer.

DEC, USA

Business Basic. BASIC language and operating system for Basic Four computers.

MAI Basic Four, USA

Aka BB3.

Aka BB4.

Business Basic Micro. Adanced version of BB. BASIC language and Operating system for Basic Four computers. Similar to BB3/BB4.

MAI Basic Four, USA

Basic Control Monitor for Xerox/SDS computers.

Scientific Data Systems, USA

Practical distributed operating system, initially aimed at 80x86/PC compatible computers. In general BCOS makes a group of computers connected by a network (a cluster of computers) behave like a single computer with multiple users.

Basic Control System for HP-2100.

Hewlett-Packard, USA

BeOS for Internet Appliances. Was a minimized version of BeOS operating system for embedded systems.

Be, USA

Discontinued operating system distribution built using the OpenSolaris source base.

India

Operating system for personal computers first developed by Be Inc. It was first written to run on BeBox hardware.

Be, USA

Operating system for Scientific Data Systems' SDS 940.

Scientific Data Systems, USA

Version of UNIX for VAX, developed at the University of California at Berkeley. Late 1970s through early 1990s. Latest version is 4.4.

U.C. Berkeley, USA

Real-time operating system designed for embedded systems.

Develer, BeRTOS community, Italy

Porgramming language and Operating system for the NEAC System 100 Office computer.

NEC, Japan

Business Executive System for Timesharing. OS for Qantel Minicomputers.

Qantel, USA

Basic Executive & Timekeeper. OS for Varian minicomputers.

USA

Early computing environment originally implemented as a batch processing operating system at Bell Labs for the IBM 704 computer.

IBM, USA

Indian Linux distribution developed by C-DAC, Chennai in order to benefit the usage of Free/Open Source Software in India.

C-DAC/NRCFOSS, India

OpenBSD-based operating system targeted exclusively at the amd64 and armv7 platforms.

Operating system developed with NASM, Free Pascal and GNU-Pascal (BK-OS 32) and Borland Pascal (BK-OS 16).

Claudio Biale, Argentina

Batch-oriented operating system for the Philco-2000 computer.

Philco, USA

Based on the LSX kernel ( UNIX version V6).

Sergey Vakulenko and Leonid Bruchis, Russia

Batch-oriented OS for the CDC 6600.

Lawrence Berkeley Laboratories, USA

Proprietary mobile operating system for the BlackBerry line of smartphones.

BlackBerry, Canada

Proprietary mobile operating system developed by BlackBerry for its BlackBerry line of smartphone handheld devices.

BlackBerry, Canada

Operating system written in COBOL.

Data General, USA

Board-level multitasking executive for National Semiconductor 8080 and Z-80 based CPU boards.

National Semiconductors, USA

Code-name for Taligent OS, successor of Pink.

Apple, USA

Also known as AOS. Concurrent and active object update to the Oberon operating system.

ETH Zurich, Switzerland

Developed jointly by Fujitsu, USAC Electronic Industrial and Uchida Yoko.

Fujitsu, Japan

Basic Monitor System.

DEC, USA

Real-time object-oriented operating kernel for embedded systems.

Baigudin Software, Russia

For medium-scale batch processing. Capable of simultaneously executing one batch process and up to two sub processes.

Fujitsu, Japan

Basic OS for Interdata (later Perkin-Elmer) minicomputers.

Interdata, USA

Batch operating system for Honeywell System 700.

Honeywell, USA

Operating system for Billings computers.

USA

Bubach Operating System. No-kernel small x86 operating system written in Assembly.

BOS with Multiprocessing of up to 4 jobs.

Fujitsu, Japan

Basic Operating System. Early interim version of DOS/360, briefly available at a few Alpha & Beta System/360 sites

IBM, USA

Business Operating Software. Business oriented OS for Z80, PDP-11, 8086, and 68000.

BOS National, USA

Business Oriented System. Floppy-disk oriented operating system for OKITAC office computers.

Oki, Japan

Business Oriented System. Hard-disk oriented operating system for OKITAC office computers.

Oki, Japan

Multitasking, multiprocessing version of BOS/5.

USA

BOS with Virtual memory control.

Fujitsu, Japan

Basic Operating Software System. Based on UNOS by Charles River Data Systems (CDRS).

MAI Basic Four, USA

Batch OS for the DEC PDP-15.

USA

Operating system for the RC-4000 Computer.

Regnecentralen, Denmark

USA

USA

USA

Batch Processing Monitor. Capable of simultaneously performing remote batch processing submitted from a remote location and multiple real-time processing tasks.

Mitsubishi, Japan

Business oriented operating system for the GRI-99.

USA

Basic Programming Support. Business-oriented OS for the IBM/360.

IBM, USA

Previously legOS. Alternative operating system for the Lego Mindstorms RCX Controller.

Operating system for GE computers.

General Electric, USA

Based on modular functions that can be dynamically called by other functions.

Real-Time Operating System.

Brazil

Operating system adopted for the Unidata series of computers.

Siemens, Germany

Now BS2000/OSD from Fujitsu-Siemens Computers (formerly Siemens Nixdorf Informationssysteme).

Siemens, Germany

First released version.

Functionally similar to OS-IV and MSP from Fujitsu.

Siemens, Germany

Berkeley Software Distribution, a variant of Unix for DEC VAX hardware.

U.C. Berkeley, USA

Later known as BSD/OS.

Small real-time OS for Z80, 6809, 8086, 68000.

Boston Systems Office, USA

Batch Time-Sharing Monitor for XDS Sigma 5/7.

USA

Business-oriented version of the TRON OS for office workstations with bitmapped displays. Now Chokanji.

Personal Media, Japan

The command line functionality is reminiscent of DOS.

Hungary

Proprietary operating system of the Burroughs small, medium and large systems, including the Unisys Clearpath/MCP systems.

Burroughs, Unisys, USA

Operating system initially developed as an early cross-platform operating system, originally produced for Intel 8080 and Motorola 6800 computers, then redeveloped for actual businesses and business models.

CAP, UK

Memory-based real-time UNIX-like executive for the PDP-11 or VAX. Runs multiple C or Pascal Tasks.

JMI Software Consultants, USA

Operating system expansion for the Commodore 64 that gives it a whole new set of sophisticated tools with a powerful and unified user interface.

OpCoders, Canada

Privileged-mode portion of V++, a scalable multiprocessor OS.

Kenneth Duda, USA

Research OS for the CDC 6400.

USA

DR DOS acquired by Caldera in 1996. See DR-DOS.

Digital Research, USA

Latest stable version.

MS-DOS compatible operating system, the descendant of DR DOS and Novell DOS.

Digital Research, USA

All operating system procedures written in ALGOL 68C, with some closely associated protected procedures in BCPL.

Cambridge University, UK

Experimental local area network architecture.

Cambridge University, UK

Capital is an Object Oriented Operating System being developed for iPAX386+ processors. It features a multithreading tasking model. The kernel itself is multithreaded and is fully preemptible giving support for Real Time processes.

Nippun Goel, India

Capability-based Reliable Operating System. Open source operating system. Microkernel EROS successor.

Strawberry Development Group, USA

Cassette Monitor System for the DEC PDP-11.

DEC, USA

Cassette Monitor system for the DEC PDP-8.

DEC, USA

Open-source operating system, based on FreeDOS kernel. CarbonOS is a successor of discontinued LightDOS. Compaible with MS-DOS.

Corbin Davenport, USA

Catalyst Operating System. Discontinued operating system for many of the Catalyst brand of legacy network switches. It was originally called XDI by the switching company Crescendo Communications, Inc. Cisco renamed it to CatOS when they acquired Crescendo in late 1993.

Cisco Systems, USA

Variant of the UNIX operating system used internally at Bell Labs for administrative databases and transaction processing.

Bell Labs, USA

Real-time multi-user multi-tasking operating system.

Concurrent Controls, USA

Communications Control Program. Limited OS for the IBM System/3.

IBM, USA

Disk Operating system compatible with CP/M.

Cromemco, USA

Linux distribution that provides a free, enterprise-class, community-supported computing platform functionally compatible with its upstream source, Red Hat Enterprise Linux.

Like OpenBLT is a cleanroom implementation of an OS based on a microkernel (codenamed Storm), announced over the summer; there is both code and documentation available on the site, as well as a downloadable and bootable demo floppy that will let you try your hand at it in no time.

Henrik Hallin and Per Lundberg, Sweden

Simple 32bit operating with simple code. Perfect to teach basics. In future it will be using 4 rings of CPU.

Fixa, Poland

Distributed OS for the Crystal Multicomputer project. Explores coarse-grained parallelism without shared memory for computationally intensive tasks.

University of Wisconsin, USA

Nano-kernel OS aimed at the support of Orthogonal Persistence.

Compact and fast real-time operating system supporting multiple architectures and released under the GPL3 license.

Giovanni Di Sirio, Italy

Operaing system for the UNIVAC 1108 in a service bureau environment.

Case Western Reserve, USA

Operating system for the CDC 6600 supercomputer. Original name of SCOPE.

Control Data, USA

Object-oriented operating system.

University of Illinois, U. of Idaho ?, USA

Proprietary microkernel OS, rival of Mach and a RTOS, (now acquired by Sun Microsystems) for telecommunication devices (cellphones, etc.) and network appliances (webphones, set top boxes, etc...).

INRIA, France

Designed to work exclusively with web applications. The Chrome OS source code was released in 2009, under the BSD license as Chromium OS.

Google, USA

Open source operating system development version of Chrome OS. Both operating systems are based on the Linux kernel.

Google, USA

Real-time Linux patch.

Virginia Tech, USA

Batch oriented disk operating system for the Cincinnati Milacron CIP/2200.

USA

Free Common Lisp development and deployment platform for Linux-based GNU systems.

Originally Internetwork Operating System. Family of software used on most Cisco Systems routers and current Cisco network switches.

Cisco Systems, USA

Colloquial term used to describe a series of operating systems developed for the Macintosh family of personal computers by Apple.

Apple, USA

Operating system written in Python with the Python VM as a micro-kernel on top of a minimal C/asm layer.

Microkernel-based system for x86 hardware. It's based on modular architecture and already supports preemptive multithreading + user-level processes.

Pype & the Clicker Development Team, Belgium

Multilevel secured operating system.

ANSSI, France

Live CD of FreeBSD.

Distributed object-based operating system.

Georgia Institute of Technology, USA

Cambridge Multiple Access System.

University of Cambridge, UK

Cambridge Model Distributed System. Sets out to provide, by means of a number of interconnected mini- and microcomputers, facilities that are similar to those provided by a time-sharing system.

University of Cambridge, UK

Cambridge Monitor System or Conversational Monitor System. Single User Interactive OS developed in conjunction with the Virtual Machine Control Program CP-40 at IBM Cambridge Laboratories. Later adapted for CP-67 and VM/370.

IBM, USA

Cloud Network Operating System.

Lenovo, China

Operating system for the CDC 1604 computer.

Control Data, USA

Now Stratify OS.

Stratify Labs, USA

Local network operating system based on UNIX, developed for the COCANET local area network.

U.C. Berkeley, USA

Free, open source, cooperative task scheduler, based on coroutines targeted for embedded microcontrollers like AVR, MSP430 and STM32.

Coherent Unix-like OS from Mark Williams Co. for PC class computers.

Mark Williams Corp., USA

ROM-based OS created by Microsoft for the TRS-80 Color Computer.

Tandy, USA

Disk operating system used with Commodore's 8-bit computers.

Commodore, USA

Released for the Apricot PC. Based on the multitasking Concurrent CP/M-86 kernel.

Network operating system for Comware switches.

Hewlett-Packard, USA

Successor of CP/M-80 and MP/M-80.

Digital Research, USA

Dual-processor variant of Concurrent CP/M for 8086 and 8080 CPUs.

Variant for the 68000.

Successor of CP/M-86 and MP/M-86 supporting limited multitasking.

BDOS 3.1 with PC-MODE (Digital Research's successor of CP/M-86 and MP/M-86).

Adaptation of Concurrent CP/M-86 for the LSI-M4, LSI Octopus and CAL PC computers.

Successor of Concurrent CP/M-86 with PC-MODE.

Digital Research, USA

Concurrent DOS 386 variant with advanced graphics terminal capabilities.

Port of Concurrent DOS to Motorola 68000 CPUs with DOS source code portability capabilities.

Dual-processor variant of Concurrent DOS for 8086 and 8080 CPUs.

Real-mode variant of Concurrent DOS with EEMS support.

Concurrent DOS variant for IBM compatible PCs.

Digital Research, USA

Replaced in 1986 by Concurrent DOS XM.

Distributed OS described as a "hunter of idle workstations," which distributes large computationally intensive jobs among available processors in a workstation pool. Renamed HTCondor.

University of Wisconsin, USA

Small romable embedded operating system for ARM processors.

Nexus, USA

Operating system for networked, memory-constrained systems with a focus on low-power wireless Internet of Things devices.

Also known variously as CTOS, BTOS and STARSYS, was a modular, message-passing, multiprocess-based operating system. Later acquired by Unisys.

Convergent Technologies, USA

Embedded real-time multi-task OS specially for ARM Cortex M series. Originally a project launched by Embest Info. Tech. Co. along with Wuhan University of Technology

CooCox, China

Customer-Oriented Optimum Language. Decimal machine language and operating system for the Melcom 81 computers.

Mitsubishi, Japan

Unreleased operating system prototype for Apple Macintosh computers of the late 1990s, intended to be released as the modern System 8 successor.

Apple, USA

Comprehensive Operating Supervisor.

General Electric, USA

Cassette OS for Computer Automation Alpha LSI and Naked Mini LSI.

USA

Commercial Operating System. Early OS for the PDP.

USA

Concurrent Operating System. Provided limited multiprogramming for Univac 9200, 9300.

USA

Operating System for GEC Computers.

USA

Cray Operating System. OS for the Cray-1 Pipelined Supercomputer.

USA

Core Operating System. For diskless real-time systems.

GEC Computers, UK

China Operating System. Linux kernel-based mobile operating system developed in China mainly targeting mobile devices, tablets and set top boxes. Developed by the Institute of Software at the Chinese Academy of Sciences (ISCAS) together with Shanghai Liantong Network Communications Technology to compete with foreign operating systems like iOS and Android.

Liantong Network Communications Technology, China

Commercial data management system for the PDP-8.

Commercial data management system for the PDP-8.

Commercial data management system for the PDP-11.

Operating system for the PDP-11.

Operating system for TOSBAC-5100/30.

Toshiba, Japan

Operating system for TOSBAC-5100/20. Was capable of continuously executing batch jobs using a magnetic tape.

Toshiba, Japan

Operating system for TOSBAC-5100/10. Was capable of continuously executing batch jobs using a magnetic tape.

Toshiba, Japan

Un OS en fran?ais enti?rment en ASM. Le site traite aussi de la prog des OS.

cos2000, France

Open Source Managed Operating System a toolkit for building operating systems written in C.

Aka Borealis. Small OS built with NASM and DJGPP.

Microkernel EROS successor, goal: be first formally verified OS.

University Johns-Hopkins, The Éros Group, USA

Control Program. A component of VM/370 for the IBM/370. CP is the kernel which implements the virtual machine.

USA

Predecessor to CP-67 on modified IBM System/360 Model 40.

IBM, USA

Discontinued computer operating system developed by Honeywell. It was a backward-compatible work-alike of the Xerox CP-V fully rewritten for Honeywell Level/66 hardware.

Honeywell, USA

Also known as CP/CMS. Virtual machine control program for the IBM 360/67. Successor to CP-40. See also CMS.

IBM, USA

Control Program for Real-Time. Realtime operating system for Xerox 550 and Sigma 9 computer systems.

Xerox, USA

Compatible successor to UTS. It supported the same CPUs as UTS plus the Xerox 560.

Xerox, USA

Control Program/Cambridge Monitor System.

IBM, USA

Originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created for Intel 8080/85-based microcomputers.

Digital Research, USA

First CP/M available for the Amstrad CPC.

Combined version of CP/M 2.2 and CP/M-86.

CompuPro, USA

The last 8-bit version of CP/M was version 3, often called CP/M Plus.

UK

CPM For Motorola 68000.

Popular operating system for 8080 and Z80 microcomputers. Each release was customized by OEMs specifically for their hardware.

CPM For Zilog Z8000.

Version of the CP/M operating system that Digital Research made for the Intel 8086 and Intel 8088. The system commands are the same as in CP/M-80

Digital Research, USA

Released for the Apricot PC. Based on the multitasking Concurrent CP/M-86 kernel.

Networking version of CP/M. Enables microcomputers to access common resources via a network. CP/NET allows microcomputers to share and transfer disk files, to share printers and consoles, and to share programs and data bases.

Digital Research, USA

Memory-resident, diskless version of CP/NET.

Digital Research, USA

Control Program Facility.

IBM, USA

Card/Paper Tape Programming System for the IBM 1130.

IBM, USA

Early OS for DEC minicomputers.

USA

Control Programming Support, subset of RPS.

IBM, USA

Operating System for FACOM System 80 office computer. Derived from BMOS.

Fujitsu, Japan

Free operating system based on the Cpcdos OSx kernel, written only with CpcdosC+ language.

Sebastien Favier, France

Operating system for Cray supercomputers. New name for UNICOS/lc.

USA

New name for UNICOS.

USA

Multi-tasking, multi-user, Unix-like OS. first Unix-like operating system for microcomputers.

Cromemco, USA

Object-oriented distributed computing system for heterogenous environments.

Software development kit (SDK) for use in developing collaborative virtual world applications.

Alan Kay, Julian Lombardi, Mark P. McCahill, Andreas Raab, David P. Reed, David A. Smith, USA

Conversation Real-time Oriented System. Floppy Disk Operating system for OKITAC System 9 series.

Oki, Japan

Conversation Real-time Oriented System. Hard-disk Operating system for OKITAC System 9 series.

Oki, Japan

Operating system, created in Samara, for the Soviet Elektronika BK-0011M and Elektronika BK-0011 microcomputers.

Russia

Operating system for the CSIRONET ?

CSIRO, Australia

Customer-oriented System Products. Operating system developed jointly by Fujitsu and USAC Electronic Industrial (which later became PFU) for the FACOM K series of office computers.

Fujitsu, Japan

For small machines.

For medium-sized machines.

For large machines.

Merge between CSP/F3 and CSP/F5.

Cassette Tape OS for Datapoint 1100, 2200, 5500.

Datapoint, USA

Real time, multitasking, multiprocessing OS for 8086 family.

Convergent Technologies, USA

Cassette Tape Operating System for early desktop systems. Capable of up to 8 simultaneous users. Replaced by OS.

Central and Communication TRON. Mainframe computers and telecommunications TRON.

NTT, Japan

Commercial single or multiuser OS for small PDP-11 systems.

DEC, USA

Commercial single or multiuser OS for small PDP-11 systems.

DEC, USA

Compatible Time-Sharing System. Developed at MIT's Computation Center for use on a modified IBM 7094.

MIT, USA

Cray Timesharing System. Successor to LTSS.

Lawrence Livermore Labs, USA

Operating system for Harris Night Hawk series.

USA

Operating system for Harris Night Hawk series.

USA

OS for Cybiko PDA.

Dispatcher-68. First operating system for the BESM-6 computer.

ITMiVT RAS, Russia

Direct Access Programming System.

Bull-General Electric, USA

Open-source Unix-like operating system. It is composed of code developed by Apple, as well as code derived from NeXTSTEP, BSD, Mach, and other free software projects.

Apple, USA

ONTAP or Data ONTAP or Clustered Data ONTAP (cDOT) or Data ONTAP 7-Mode is NetApp's proprietary operating system used in storage disk arrays such as NetApp FAS and AFF (also known as NetApp Filer), ONTAP Select and Cloud Volumes ONTAP.

NetApp, USA

DataPac version of Multiuser DOS.

DataPac Australasia, Australia

Derivative of Datapac Multiuser DOS.

DataPac Australasia, Australia

Operating system for the Tandy TRS-80. Simple updates to TRSDOS to support the Percom double-density board.

Percom Data, USA

Disk Based Operating System. For General Automation SPC-16 & System 18/30.

General Automation, USA

DataCenter/OSx for Pyramid's MIPS-based systems. Was the first symmetric multiprocessing (SMP) implementation on Unix System V Release 4. DC/OSx was superseded by the SINIX operating system.

Pyramid Technology, USA

Operating system for Omron workstations.

Japan

Operating system for a distributed network of PDP-11 virtual machines at the University of Maryland.

David Mills, USA

Linux-based firmware for wireless routers and access points.

Unix-like operating system composed entirely of free software packaged by a team of volunteers.

Dell Real Mode Kernel. close to MS-DOS and PC-DOS. OS used when booting to the Restore or Utility partitions on recent Dell systems.

Dell, USA

Message-based OS for the CRAY-1.

Los Alamos, USA

Dialogovaya Edinaya Mobilnaya Operatsionnaya Sistema. MNOS alternative.

Kurchatov Institute of Atomic Energy, DEMOS Co-operative, Russia

A distributed version of the DEMOS operating system. Message-based, featuring process migration.

U.C. Berkeley, USA

Kernel for multiplexing virtual machines.

University of Washington, USA

Certified to DO-178B, Level A since 1998.

DDC-I, USA

Real-time, Unix-like OS for 16-bit microprocessor families and Micro-Vax, DGC MV series.

Destek Group, USA

Operating system introduced with the Tandy 1000 computer.

Tandy, USA

Unix-derivative, desktop-oriented operating system based on FreeBSD.

Peter Hofer, Daniel Seuffert, Austria

Text mode multitasking operating environment.

Quarterdeck, USA

QEMM 386 multi-tasking user interface.

Quarterdeck, USA

X-windowing GUI.

Quarterdeck, USA

Extensible operating system (dex-os). Educational operating system that supports a plug-in like architecture and aims to achieve zero static inter-module calls.

Fast 32bit pmode operating system for the PC (Intel, AMD, etc.). Everything in this operating system is focused on speed: the architecture, it's avoidance of virtualization, and it is completely written in assembly.

32-bit operating system written in x86 assembly.

Real mode OS (similar to XOA-DOS). Built using NASM for x86 (386+) CPU's. And designed for normal floppy disks. Source available and some tutorials/documents. Main purpose of the site is to initally learn about OS development rather than commercial or linux like use.

Unix operating system.

Data General, USA

Database dialog OS for SMEP computers.

Russia

Old name for Tru64 UNIX. Derived from OSF/1, became HP's Tru64 UNIX.

DEC, USA

Illumos based platform (Solaris).

Multitasking preemptive, real-time operating system. The system is designed for Texas Instruments MSP430x microcontrollers.

EleSoftRom, Poland

Operating system for the Atari Portfolio.

DIP, Canada

Was the first prototype system of the DIPS series.

NTT, Japan

Dispetcher Paketov. Operating system for the BESM-6 computer. Used in Atomic research.

ITMiVT RAS, Russia

Object-oriented C++ RTOS for microcontrollers.

Distributed OS for a network of 68000s.

USA

Message-based distributed version of Unix.

University of Cape Town, USA

Operating system for the Chinese DJS210 and DJS220. Multiprogrammed and deadlock-free.

China

Duplex Multi Environment Real Time. Operating system for the AT&T 3B20D telephone switching minicomputer, designed for high availability. DMERT was later renamed Unix RTR (Real-Time Reliable).

Bell Labs, USA

Disk Monitor System. Single-task batch-oriented system.

IBM, USA

Disk Monitor System for General Automation System 18/30.

USA

Disk Management System.

AT&T, USA

Disk Monitor System Version 2.

Time-sharing operating system for the DNEPR-2.

Russia

Unix-like real-time operating system.

Dataindustrier, Sweden

Distributed Network Operating System. General purpose, multitasking operating system designed to operate with the Texas Instruments 990/10, 990/10A and 990/12 minicomputers.

Texas Instruments, USA

Operating system for NCR computers.

USA

Small general purpose real-time operating system based on the FreeRTOS kernel.

Daniel Zorychta, Poland

Robust, reliable, fast multi-tasking operating system. Highly configurable to the user's needs.

Samuel A. Falvo II, Portugal

One of the first network-based systems. Run on Apollo/Domain hardware. Later bought by Hewlett-Packard.

Apollo Computer, USA