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

OnixOS Arch is a Linux-based and open source distribution.

USA

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

Arrcus, USA

Successor to MLNX-OS. High performance, flexible and cloud-scale switch operating system, designed for the demands of next-generation data centers.

Mellanox, USA

Free and open-source operating system under development primarily for smartphones, based on the Alpine Linux distribution.

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

Alibaba, China

Lightweight RTOS-based platform to support low-end IoT devices.

Japanese roughly equivalent to 'a certain'. Hobby operating system and kernel developed largely independently (notably contrary to most modern OSes.

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".

Google, USA

Linux Embedded Development Environment. Fork of the OpenWrt project and shared many of the same goals.

Free and open-source operating system for set-top boxes, smartphones and tablet computers, based on the Android mobile platform.

Mobile operating system.

Alibaba Group, China

Small real-time operating system for connected, resource-constrained devices supporting multiple architectures and released under the Apache License 2.0.

Open, secure and programable next-generation Network OS.

Pluribus Network, USA

IoT operating system, using JavaScript as its programing language.

Aka Windows NT 10. Series of personal computer operating systems produced by Microsoft as part of its Windows NT family of operating systems.

Microsoft, USA

Operating system developed by Apple for the fourth-generation and later Apple TV digital media player.

Apple, USA

Cloud Network Operating System.

Lenovo, China

Open source network operating system that originated with Hewlett Packard Enterprise (HPE), is now under the wing of the Linux Foundation.

Hewlett-Packard, USA

Open source, FreeBSD-based firewall and routing software developed by Deciso, a company in the Netherlands that makes hardware and sells support packages for OPNsense.

Deciso, Netherlands

Written in Rust.

Operating system for the Apple Watch.

Apple, USA

Ultra securized OS for Archos' GranitePhone derived from Android.

Sikur, USA

Full-featured real-time operating system designed specifically for embedded applications.

Blunk Microsystems, USA

Partially POSIX-compatible microkernel operating system.

Kapesky Lab, Russia

Mobile operating system of the Apple Watch.

Apple, USA

Hybrid real-time energy-efficient operating system for the resource-constrained wireless sensor nodes.

Wuhan University, Blaise Pascal University, China/France

Open Network Linux. Linux distribution for open hardware switches based on Debian.

Free and open-source operating system for personal computers.

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

Facebook Open Switching System. Linux-based operating system for Wedge switch.

Facebook, USA

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

General purpose Linux distribution used commonly as a mobile operating system combining the Linux kernel for a particular hardware platform.

Jolla, Finland

Open source Operating System for Internet of Things.

Cesanta, Ireland

Hobby Unix-like operating system based on ToaruOS.

Canonical agreement with the Ministry of Industry and Information Technology of the People's Republic of China to release an Ubuntu-based Linux OS.

Canonical, UK

Operating system for the eighth-generation home video game console, Xbox One. It is a Windows-based operating system using the Hyper-V virtual machine monitor.

Microsoft, USA

Open-source operating system – made for smartphones, tablet computers and smart TVs. Designed by Mozilla and external contributors.

Mozilla, USA

Formerly J Operating System, SparrowOS and LoseThos. Biblical-themed lightweight operating system designed to be the Third Temple prophesied in the Bible.

Cloud computing focused computer operating system. It is a special-purpose operating system built to run as a guest on top of a virtual machine, thus it does not include drivers for bare-metal hardware.

Cloudius Systems, Israel

Proprietary mobile operating system for the BlackBerry line of smartphones.

BlackBerry, Canada

GNU/Linux-libre distribution for computers with minimal resources, such as the Ben Nanonote, ath9k-based Wi-Fi routers, and other hardware with emphasis on free software.

USA

Aka Windows NT 6.2. Windows 8 introduced major changes to the operating system's platform and user interface to improve its user experience on tablets.

Microsoft, USA

Linux distribution that Google uses internally.

Google, USA

Security-focused desktop operating system that aims to provide security through isolation.

Invisible Things Lab, Poland

Small, versatile, high-assurance real-time operating system (OS) for embedded micro-controllers.

Breakaway Consulting, Australia

Formerly Condows. Renamed in 2012 after trademark law issues. Open-source high-throughput computing software framework for coarse-grained distributed parallelization of computationally intensive tasks

University of Wisconsin–Madison, USA

Mobile operating system for Huawey smartphones. Formerly Emotion UI.

Huawey, China

Software platform for the creation of sophisticated network equipment that accelerates, analyzes, and secures the flood of traffic for next—generation networks.

Wind River, Intel, USA

Open source operating system for embedded devices that provides the NAS (Network-Attached Storage) server. See XigmaNAS.

Netherlands

32-bit operating system written in x86 assembly.

Independent operating system, forked from FreeBSD 10.

Iran

Earlier called LiMo Platform. 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.

Samsung Electronics, The Linux Foundation, Korea

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

Based on Windows Server 2008 R2.

Microsoft, USA

Research and experimental operating system. Based on a preemptible microkernel design.

Charles University in Prague, Czech Republic

Also known as Ubuntu Phone. Mobile version of the Ubuntu operating system that was originally developed by Canonical and is now being developed by the UBports community.

Canonical, UK

OpenIndiana/Illumos based Solaris distribution for reviving SPARC hardware support.

Martin Bochnig, Germany

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

Samsung Electronics, Korea

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

EleSoftRom, Poland

Free operating system based on the FreeDOS kernel.

Corbin Davenport, USA

Microsoft Azure (formerly Windows Azure). Cloud computing service created by Microsoft for building, testing, deploying, and managing applications and services through a global network of Microsoft-managed data centers.

Microsoft, USA

Unix-like operating system based on TrueOS with Xfce and MATE as its default desktop environments.

Real-Time Operating System especially developed for hard real-time safety critical avionics applications.

TUBITAK Informatics, Turkey

Genetic Lifeform and Disk Operating System. Free and open-source operating system based on FreeDOS 1.0, developed as a replacement for Microsoft DOS (MS-DOS).

Corbin Davenport, USA

Community project to make Darwin more usable (some people think of it as the informal successor to OpenDarwin.

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.

Sun Microsystems, USA

Storage appliance based on NAS4Free and FreeBSD.

France

Windows Phone mobile client operating system.

Microsoft, USA

General-purpose operating system. Debian derivative using the illumos kernel, libc, and SMF init system (formerly OpenSolaris).

France

Linux kernel-based multitasking operating system for smart devices such as smart TVs and it has been used as a mobile operating system.

Hewlett-Packard, USA

Aim of embKernel is to produce an unified C++ source for embedded devices.

Aka Fastpath. Off-the-shelf (Linux based) network operating system on x86-based switches.

Broadcom, USA

Contains original Unix (SVR4) code derived from the OpenSolaris (discontinued by Oracle in favor of Solaris 11 Express).

Free operating system (OS) based on the Android mobile platform that aims to replace all proprietary Android components with free-software counterparts.

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

Sebastien Favier, France

Operating system for ZX Spectrum disk interfaces DivIDE and DivMMC.

Unix-like BSD based operating system.

Juraj Sipos, Slovakia

Secured operating for the ARCANE smartphone.

Fantome, Hong-Kong

Platform release of EOS that is supported on Amazon Web Service (AWS), Microsoft Azure and other public clouds.

Arista, USA

Complete SDN operating system based on Open Network Linux (ONL), an open source effort within the Open Compute Project.

Big Switch Networks, USA

From merger of Maemo & Moblin.

China Standard Software and the National University of Defense Technology strategic partnership to launch a linux version ok Kylin intended for use by government offices, national defense, energy and other sectors of the Chinese economy.

China Standard Software, China

Bootable live CD based on the NetBSD Operating System.

Germany

Real-time operating system developed for a variety of microcontroller architectures.

See LG webOS.

Palm, USA

Aka Windows NT 6.1. Code name Blackcomb and Vienna.

Microsoft, USA

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

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

Mobile operating system running on the Linux kernel. It is based on technologies initially developed by Android Inc.

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

Extensible Operating System. Fully programmable and highly modular, Linux-based network operation system, using familiar industry standard CLI. Based on Fedora.

Arista Networks, USA

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

RusBitTech, Russia

Successor to Symbian OS.

Symbian, UK

Free Open Source software operating system development project, aiming to replace eventually all OS/2 subsystems with Open source analogues.

Mobile Operating system based on an Linux core.

Palm, USA

South Korean OS based on Windows.

TmaxSoft, Korea

Operating system kernel designed to run on 32bit microcontrollers.

Free OpenWrt-based Linux distribution for a range of wireless routers based on Broadcom or Atheros chipsets.

Distributed OS derived from Plan 9 and Off++ microkernel.

Universidad Rev Juan Carlos, Madrid, Spain

Operating system framework for microkernels. First conceived as the Bastei OS Architecture.

Genode Labs, Germany

Computer operating system based on the .NET Framework and related programming language C#.

HeartOS Posix-based Hard Real-Time Operating System.

DDC-I, USA

Discontinued, open source computer operating system based on Solaris.

Sun Microsystems, USA

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

North Korean Linux distribution. Prior to its release, computers in North Korea typically used Red Hat Linux and Windows XP

Korea Computer Center, North Korea

Small real time operating systema applied to an onboard project for General Aviation. . The focus of the operating system is predictability, stability, safety and simplicity.

ETHZ, Switzerland

Exokernel-based single address space operating system.

Return Infinity, USA

Discontinued computer operating system based on OpenSolaris and Ubuntu that runs on IA-32- and x86-64-based systems. Replaced by Illumian in 2011.

Nexenta Systems, USA

Real-time operating system with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 32-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards

Firmware replacement for Lego Mindstorms programmable bricks.

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

Research operating system written mostly in managed code (C#).

Microsoft, USA

Aka good OS. Ubuntu-based Linux distribution.

Good OS LLC, USA

Real-time operating system made by Canon and is used in their latest digital cameras and camcorders.

Canon, Japan

Based on Windows Server 2003.

Microsoft, USA

Linux kernel-based mobile operating system.

Motorola, USA

Operating system for smartphones developed by the Openmoko project. It is based on the Ångström distribution, comprising various pieces of free software.

Linux distribution packaged and freely distributed by Oracle. Uses a version-naming convention identical to that of Red Hat Enterprise Linux.

Oracle, USA

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

University Johns-Hopkins, The Éros Group, USA

Digital media player and microconsole.

Apple, USA

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

Formerly iPhone OS. Mobile operating system created and developed by Apple exclusively for its hardware.

Apple, USA

Operating system for media player.

iriver, Korea

Very concise portable real time - preemptive operating system (RTOS) for embedded microcontrollers.

Forked from FreeBSD 6.1.

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

BSD based OS for Cavium Octeon MIPS architecture processors.

Paxym, USA

Chines operating system. The first versions were based on FreeBSD and were intended for use by the Chinese military and other government organizations.

National University of Defense Technology, China

Open source firewall/router computer software distribution based on FreeBSD.

Rubicon Communications, USA

Lightweight microkernel.

Green Hills Software, USA

Previously known as PC-BSD. Unix-like, server-oriented operating system built upon the most recent releases of FreeBSD-CURRENT.

iXsystems, USA

Multilevel secured operating system.

ANSSI, France

Free operating system built on the FreeDOS kernel with DJGPP.

Community-driven Linux distribution based on Debian and Ubuntu that strives to be a "modern, elegant and comfortable operating system which is both powerful and easy to use.

Clément Lefèbvre, Jamie Boo Birse, Kendall Weaver,, International

Aka Windows NT 6.0

Microsoft, USA

Computer operating system developed originally by Nintendo and since 2008 by Esrille. It is open source and runs natively on x86 platforms.

Nintendo, Japan

Teaching operating system developed in the summer of 2006 for MIT's operating systems course.

MIT, USA

Small open-source Linux distribution for servers and embedded systems which aims to provide network services.

Uses only 30K code.

Frizzz, Germany

SYmbiosis Multitasking Based Operating System. GUI based modern micro-kernel OS for x86, ARM and PowerPC processors. Used and developed further at Technical University of Munich.

Miray Software, UK

IS-DOS vesion for Nemo KAY.

Russia

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.

Flexible Microkernel Infrastructure/Operating System. Successor of VSTa.

Based on the LSX kernel ( UNIX version V6).

Sergey Vakulenko and Leonid Bruchis, Russia

Kernel-based Virtual Machine. Virtualization infrastructure for the Linux kernel that turns it into a hypervisor.

Qumranet, Open Virtualization Alliance, USA

OpenSolaris based complete open-source operating system.

Germany

Linux kernel operating system targeted to smartphones.

MonteVista Software, USA

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

Strawberry Development Group, USA

Open Source networking OS by Novell. Can incorporate either SUSE Linux or Novell NetWare as its kernel.

Novell, USA

Open source, royalty-free, real-time operating system for embedded systems. It is designed and implemented for resource-constrained systems that require predictable timing behavior.

Operating System for Ubiquiti M Series Products.

Ubiquiti Networks, USA

Thin client operating system based on Windows XP Embedded and is optimized for older, less powerful hardware.

Microsoft, USA

Formerly SUSE Linux and SuSE Linux Professional, is a Linux distribution sponsored by SUSE Linux GmbH and other companies.

Lightweight Operating System. Designed to fit on a floppy.

Udateable software and operating system for the Xbox 360.

Microsoft, USA

Based on Caldera OpenDOS 7.01.

z/Architecture extension.

IBM, USA

Virtual Storage Extended. Latest version of the four decades old DOS lineage, supports 64-bit addresses, multiprocessing, multiprogramming, SNA, TCP/IP, and some virtual machine features in support of Linux workloads.

IBM, USA

Software platform developed by Nokia for smartphones and Internet tablets.

Nokia, Finland

Open source microkernel based operating system with POSIX complience.

Manish Regmi, Nepal

Linux-based firmware for wireless routers and access points.

Microkernel based multiprocessor, multitasking, multithreading operating system for the IBM-PC Intel i386 systems. It is developed in Department of Computer Science of Bahahuddin Zakariya University, Multan Pakistan.

Bahahuddin Zakariya University, Multan, Pakistan

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

Peter Hofer, Daniel Seuffert, Austria

Real-time operating system designed for Internet of Things appliances. Successor to the Phoenix operating system.

Phoenix Systems, USA

German Language OS Project.

Dominic Fischer, Switzerland

Free and open-source Unix-like operating system forked from FreeBSD 4.8.

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

Free and open-source operating system and Linux distribution based on Debian.

Canonical, Ubuntu community, UK

Micro disk operating system for PC/AT compatibles with legacy floppy drive.

K. Gondow and M. Ohba, Japan

Unix-like operating system based on OpenBSD 3.3, also incorporating code from other BSD-like operating systems. Its focus was on security and easy administration.

Open source project for embedded operating system based on Linux, primarily used on embedded devices to route network traffic.

Research kernel.

Epita System Laboratory, France

High-performance virtualized Linux. microkernel OS; usually a real time embedded OS.

National ICT Australia, Australia

Server operating system derived from Debian GNU/Linux with an integrated management system for the central and cross-platform administration of servers, services, clients, desktops and users as well as virtualized computers operated in UCS.

Univention, Germany

Real-time networking operating system.

Lantronix, USA

Operating system designed around idiomatic C++ concepts such as RAII, iterators, and streams.

Can execute DOS tasks. Runs from MS-DOS version 7 (Windows 95,98).

Alexander Kobets, Russia

Network operating system used in newer Extreme Networks network switches.

Extreme Networks, USA

Tabos is a new operating system based on a modular monolithic kernel with module loading support, using the x86 platform features.

Jan-Michael Brummer, Germany

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 Realtime Operating System.

Didactic Linux-like kernel. Multi-threading operating system for IA-32 architecture.

Andrea Righi, Italy

Small open source x86 operating system forked off from MenuetOS.

Live CD based on the FreeBSD.

DOS Like 32BIT "GUI" OS.

LightCone, Japan

Scout in Linux Kernel. Linux kernel module which transforms a standard Linux OS into Scout.

University of Princeton, USA

Object Oriented 32 bit operating system. It aims to be a complete multitasking kernel.

Portable media based operating system. It loads itself into RAM and allows you to do system maintenance related tasks.

Or Yocto Project. Build automation framework and cross-compile environment used to create Linux distributions for embedded devices.

Open source OS designed to be binary compatible with Windows NT and its variants (Windows XP, Windows 2000, etc.); currently in development phase.

Brand name for a group of server operating systems released by Microsoft.

Microsoft, USA

Was IMS' attempt to create the "Next Generation" of REAL/32, also named "REAL/32 for the internet age". REAL/NG promised "increased range of hardware from PCs to x86 multi-processor server systems".

Intelligent Micro Software, UK

32-bit operating system with a primitive shell implemented.

University of Madras, India

"Modular" operating system for the x86 desktop. The main goals of this os are: Portability, Stability, Security, and Customizable.

Multilevel secure computer operating system.

BAE Systems, UK

Desktop, workstation, server, cloud OS.

Nanos is a protected mode nanokernel OS for x86 computers. It is written in assembly and assembled with NASM.

Peter Hultqvist, Sweden

Very simple multithreaded OS for the Evaluator-7T board from ARM. It is based on JayOS. It features pre-emptive multi-threading, communication between threads, etc. and hardware drivers.

Wilhem Meignan, France

"Toy OS" that runs on the Gameboy Advance. It provides preemptive threads, semaphores, condition variables, and message queues.

Managed code operating system. a possible commercial implementation of the Singularity operating system

Microsoft, USA

Java New Operating System Design Effort. Written 99% in Java (native compiled), provides own JVM and JIT compiler. Based on GNU Classpath.

Martin Husted Hartvig, Germany

Real-time operating system kernel for embedded devices that has been ported to 35 microcontroller platforms. It is distributed under the MIT License.

Real Time Engineers, UK

Originally called MirBSD. Free and open source operating system which started as a fork of OpenBSD.

Minimalistic 32-bit x86 operating system kernel for network server appliances running on standard PC hardware.

Simple, easy, fast realtime 32bit GUI OS.

Bogdan Ontanu, Romania

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

Linux for servers.

Red Hat, USA

Open-source OSEK/VDX Kernel.

Evidence, France

Free and open-source software replacement for the OEM firmware in various forms of digital audio players (DAPs) with an original kernel.

Modern, independently originated OS. See AtheOS.

K. Van Der Vliet, K. de Vos, R. Caudill, A. Klenke, H. Isaksson, UK

SYstem for MOBIle applications. proprietary modern and mobile real-time operating system. Designed for the area of embedded and mobile systems.

Miray Software, Germany

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

Claudio Biale, Argentina

Embedded operating system.

Java operating system that focuses on a flexible and robust operating system architecture developed as an open source system.

University of Erlangen, Germany

Open-source research operating system on PowerPC or x86 based cache-coherent multiprocessor systems.

IBM, USA

Open source real-time operating system designed for 32-bit microcontrollers. It is standardized by the T-Engine Forum, which distributes it under a "T-License" license agreement.

Microkernel-based real-time OS that aims for POSIX compliance; while open sourced, the people behind it intend to make it a commercial venture and release a packaged version that will include additional things not present in the opensource version.

Ralph Gerlich, Germany

The goal is to create a production quality micro kernel based on the latest findings in operating system research. The result will be a micro-kernel having the following features: no abstractions, safe those necessary for protection, minimal set of primitives, support for capability based security, support for resource management needed for real-time and multimedia applications.

Open source. Inspired by BeOS, under development. Specifically targeting personal computing.

Warp 4.5/Workspace on Demand, rebundled by Serenity Systems International.

IBM, USA

Aka Windows NT 5.1

Microsoft, USA

Replacement for TOS (the operating system of the Atari ST and its successors), released as free software.

Real-time development framework cooperating with the Linux kernel, to provide a pervasive, interface-agnostic, hard real-time support to user space applications, seamlessly integrated into the Linux environment.

See MacOS.

Apple, USA

Separately sold operating system add-on which provides additional server programs along with management and administration tools for macOS.

Apple, USA

Formerly Mac OS X and OS X.

Apple, 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

Small, open-source, Unix-like OS. Designed to preform networking tasks and other file-oriented processes whiltaking up very little of the computer's processing power.

Visual Operating System. The operating system is licensed under the GNU GPL.

Andy McLaughlin, Canada

µClinux-based Linux distribution designed specifically to run on Apple iPod.

Apple, USA

Full-featured and robust OS that scales down to meet the constrained resource requirements of realtime embedded systems.

Quantum Software Systems, Canada

Kernel Mode Linux is a Linux OS variant which execute user.

Toshiyuki Maeda and Akinori Yonezawa, Japan

Force10 Operating System. Firmware family used on Force10 Ethernet switches.

Operating system created for educational purposes.

A.Baranovskis, A.Ruckij, V.Birbilas, Lituania

Multum In Parvo Operating System. Cooperative multitasking RTOS designed for single-chip micro-controllers with severely limited RAM (e.g. less than 256 bytes) and ROM. It provides the flexibility of an RTOS in low-cost embedded designs.

Antonino Calderone, Italy

Priority-based, preemptive, multitasking, real-time operating system designed and optimized for high performance DSPs and media-centric microprocessors.

Unicoi Systems, USA

Expanded OS for Amstrad computers optimized for speeed.

Future Soft, Germany

Portable microkernel and a set of operating system services.

Real-time operating system for embedded applications.

Eremex, Russia

Extremely fast microkernel available for x86, ARM, MIPS and other architectures.

University of Karlsruhe, Germany, Germany

Unnamed NetBSD variant for Airport Extreme and Time Capsule.

Apple, USA

Simple to use but highly sure and stable OS.

Massimo Angiolani, Italy

Based on a concept of persistent virtual memory, and is managed-code oriented. Phantom OS is one of a few OSes that are not based on classical concepts of Unix-like systems.

Digital Zone, Russia

Real-time operating system, used for instance on LabVIEW real-time targets. Now part of IntervalZero.

Pha Lap, USA

Free open-source RTOS for Critical Systems.

CEA, Delphi, Geensys, France

Real-Time Operating System.

Brazil

Network operating system based on Debian.

Mellanox, USA

Real-Time Operating System.

Tiny Real-Time Preemptive Operating System intended for use with Single-Chip Microcontrollers.

Russia

Open source operating system for Ethernut boards.

Ethernut community, Germany

Para-virtualised guest operating system for less complex systems which provides the ARINC 653 P4 subset as a lightweight alternative to LithOS (P1) for embedded real time operating systems used in avionics.

FentISS, Spain

Static RTOS for small embedded systems. Its API is aligned with OSEK/VDX OS and AUTOSAR OS 4.2 standards.

LS2N (ex-IRCCyN) Laboratory, France

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

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

Highly configurable and very fast real time operating system. It targets a wide range of architectures, from the small 8 bit processors with very low memory till huge architectures like 32 bit processors with lots of memory.

Real-time operating system for PIC18 microntroller.

Pragmatec, France

Certified real time operating system for safety and security critical embedded systems.

SYSGO, Germany

See DOS (3).

GEC Computers, UK

Tiny Linux-like real-time operating system kernel, optimized for ARM Cortex-M series microprocessors. Based on the OSEK/VDX standard.

Full blown 64-bit PicoLisp runs directly on a standard x86-64 PC hardware.

Open source POSIX "compliant" Operating System for deeply embedded devices. Based on embOS. See Tauon.

Philippe Le Boulanger, France

Real-time kernel.

Code Time, USA

GNU/Linux-libre operating system for computers with minimal resources, such as the Ben Nanonote, ath9k based Wi-Fi routers. LibreWRT was merged to the libreCMC project in 2015.

Jason Self, Denver Gingerich, USA

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

Open-source operating system for x86 computers, based on DR-DOS/OpenDOS 7.01.

Corbin Davenport, USA

Aka Windows NT 5.0. Four editions of Windows 2000 were released: Professional, Server, Advanced Server, and Datacenter Server.

Microsoft, USA

Unix-like OS of the BSD family which provides a set of trusted operating system extensions to the FreeBSD operating system, targeting the Common Criteria for Information Technology Security Evaluation (CC).

Robert Watson, USA

Partitioned Operating System. Real-time embedded operating system for safety-critical systems (avionics, aerospace). It provides several functionalities and complies with many industrial standards, such as ARINC653 or POSIX. POK was designed to be used in safety-critical systems as well as in public systems.

France

MS-DOS compatible operating system with the original FreeDOS kernel.

Pascquale Villani, Italy

LiveCD based on OpenBSD 3.8.

Gabriel Paderni, France

Unix-like operating system developed in order to bring Gentoo Linux design, structure, and tools such as Portage and the Gentoo Linux base layout to the FreeBSD operating system.

Real Time Operating System.

Softwave Wireless, France

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

Small Devices Portable Operating System. Mini operating system providing basic scheduling services (cooperative and real time modes) and an hardware abstraction layer enabling the user to quickly developp embedded applications minimizing the need to learn specific processor architectural details.

Embedded firewall distribution of FreeBSD. It provides a small image which can be put on Compact Flash cards as well as on CD-ROMs and hard disks.

Manuel Kasper, Switzerland

Gentoo BSD subproject to port Gentoo features such as Portage to the OpenBSD operating system.

Embedded Linux.

MonteVista Software, USA

Open platform for developing, delivering, and driving real-world, broadband digital and analog video over two-way hybrid fiber coax (HFC) systems.

PowerTV, USA

Provide a GNU userland managed by Portage with a NetBSD kernel.

AmigaOS-like computer operating system. It is a mixed proprietary and open source OS produced for the Pegasos PowerPC processor based computer, PowerUP accelerator equipped Amiga computers.

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

Corbin Davenport, USA

Soft Hard Real-time Kernel. Completely configurable kernel architecture designed for supporting hard, soft, and non real-time applications with interchangeable scheduling algorithms. Evolution of the Hartik Kernel and it is based on the OSLib Project.

Sant'Anna School of Advanced Studies, Pisa, Italy

TU Dresden Research Operating System.

TU Dresden, Germany

Unix clone project for the old 8086 PCs, from former USSR.

Serge Pustovoitoff, Russia

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

Extremely lightweight stackless threads designed for severely memory constrained systems.

Adam Dunkels, Sweden

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

Fixa, Poland

Open source micro real time kernel.

SpanIdea, USA

Embedded Programming Platform.

Erik Moqvist, Sweden

CD boot OS based on Debian GNU/kFreeBSD, which is based on Debian, GNU and the kernel of FreeBSD.

USA

RTOS designed special for AVR microcontrollers.

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

Giovanni Di Sirio, Italy

Unique combination of Darwin and GNU.

Real-time Linux patch.

Virginia Tech, USA

Quantum Platform. Family of lightweight, open source software frameworks for building responsive and modular real-time embedded applications as systems of cooperating, event-driven active objects (actors).

Quantum Leaps, USA

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

Live CD of FreeBSD.

Application platform for embedded Linux-based mobile computing devices such as personal digital assistants, video projectors and mobile phones.

Qt Software, Finland

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

Open source OS.

Chris Doman, UK

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

Now Stratify OS.

Stratify Labs, USA

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

Embedded Parallel Operating System.

Brazil

x86 based OS written entirely in assembly. Provides protection with segmentation. Multithreaded with support for DOS, DPMI and Win32 console apps. Possible to add other emulated environments like UNIX.

Leif Ekblad, Sweden

Aka Windows ME (Windows 4.9). Familial version of Windows 2000.

Microsoft, USA

Just another view on how should OS be designed.

Dozz, Finland

Based on Windows CE, but for a smaller form factor.

Microsoft, USA

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

Network operating system for Comware switches.

Hewlett-Packard, USA

SmartEdge Operating System.

Ericsson, Sweden

Provides a commercial license for Amazon FreeRTOS. This includes a license for the FreeRTOS kernel as well as, if needed, the additional software libraries that make up Amazon FreeRTOS.

Real Time Engineers, USA

Illumos distribution for cloud computing with Kernel-based Virtual Machine integration.

Joyent, USA

Minimalistic real-time kernel for the HC(S)08 core by Freescale and Atmel AVR.

Small multithreading real time operating system (RTOS), based on the FreeRTOS kernel, for Arduino compatible boards.

Robot Group, Argentina

Full fledged open source, x86 based, 32bit Protected mode, multitasking operating system.

Free open source Graphical Desktop for DOS for run Microsoft Windows, Microsoft DOS and Linux programs. Based on Wine, Linux and DOSEMU.

Emanuel Chanampa, Argentina

Research Operating System. It is written for the i386 processor family, using C (gcc) and some Assembly (nasm).

Francesco Frigo, Italy

BSD based operating system.

Real-time embedded operating system, that allows programmers to run threads, simultaneously on the CPU and FPGA fabric.

University of Arkansas, USA

Opensolaris based distribution.

Martin Bochnig, Germany

Brand-new OS designed specially for low-power device, such as Internet-of-Things (IoT).

socware.net, International

Linux-based operating system for the Elbrus 801-PC.

Russia

Para-virtualised guest operating system which provides the primitives to create the system resources (blackboards, buffers, events, semaphores...) and the mechanisms to create threads, timers and the process scheduler.

FentISS, Spain

Core Operating System. For diskless real-time systems.

GEC Computers, UK

Preemptive single-stack kernel.

OBP Research, Finland

Server Oriented Operating System. Operating system (OS) specially designed for embedded systems.

David Donari, Leo Ordinez, Rodrigo Santos, Brazil

Open-source operating system that combines technologies from Nexenta OS, OpenIndiana and Debian GNU/Linux. Successor of a discontinued Nexenta OS.

RTOS 32 Bit Open Standards, Linux Compatible, Ultra Tiny Size, Modularity, POSIX-compliant RTOS that supports a variety of wireless modules and provides a complete set of security protocols.

RoweBots, USA

Extends OS/400 with significant interoperability features.

IBM, USA

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.

Real-time operating system designed to be used as a foundation for the development of embedded real-time applications for a wide range of microcontrollers.

SEGGER Microcontroller, Germany

Configurable operating system kernel designed for resource constrained and embedded systems.

Embedded firewall distribution of FreeBSD, one of the BSD operating system descendants.

Service Router Operating System. Based on VxWorks.

Alcatel-Lucent, USA

Real-time operating system is designed specifically for mission-critical server and embedded applications.

Concurrent, USA

InterLink Internet Operating System. Research OS designed for routing.

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.

Enterprise Networking Operating System. Data center-class network operating system.

Lenovo, China

Operating system for personal computers. Alow PC users to run Android mobile apps on any compatible Intel-based PC.

Jide Technology, China

eXtreme Minimal Kernel. Real-time operating system that is designed for minimal RAM/ROM use.

Shift-Right Technologies, USA

Operating system for McData (now Brocade) switches.

McDATA, USA

Free, extremely simple, amazingly tiny and very fast real-time operating system (RTOS) designed for deeply embedded applications.

Live CD protected-mode OS.

Stefan Mayer, Austria

Free Micro-Kernel Based Open Source Operating System.

Frank Anemaet, Daniel Pischl, Netherlands

X-OS - French OS Project.

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

Successor of REAL/32.

Intelligent Micro Software, UK

Desktop focused distribution based on Nexenta Core Platform 2.0.

X Operating System.

Microcontroller operating system designed to bring the software innovation model that has made computers and smartphones enormously successful to microcontroller hardware.

Statify Labs, USA

Small operating system for networked, memory-constrained systems with a focus on low-power wireless Internet of Things (IoT) devices.

FU Berlin, INRIA, HAW Hamburg, Germany

Real-time operating system.

Green Hills Software, USA

Operating system for embedded microcontrollers.

Russia

OS/390 supported z/Architecture, 64-bit addressing.

IBM, USA

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

USA

Yet Another Small OS. Free real-time OS especially dedicated to ARM Cortex-M3 micro-controllers.

Free, simple and tiny cooperative operating system designed for deeply embedded applications.

Non-preemptive, multitasking, priority based RTOS.

Unix-like OS, a commercial version of 4.4BSD using Mach on 680x0 and PPC MacIntoshes.

Tenon Intersystems, USA

z/Architecture version of the VM OS with 64-bit addressing.

IBM, USA

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

Formerly Mac OS X Server and OS X Server. separately sold operating system add-on which provides additional server programs along with management and administration tools for macOS.

Apple, USA

Next-generation operating system for the most performant embedded hardware available today. Maestro is designed specifically for multi- and many-core processors and provides reliable parallelism to application developers.

Hipperos, Belgium

Magic Communicating Applications Platform. Discontinued object-oriented operating system for PDAs.

General Magic, USA

Realtime Onboard Dependable Operating System. Real-time operating system for embedded systems and was designed for application domains demanding high dependability.

German Aerospace Center, Germany

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.

Formerly yellowTAB ZETA. Based on BeOS source code.

yellowTAB, USA

OpenBSD live CD.

France

OS for Cybiko PDA.

Sophisticated, modern RTOS and application development platform, targeted towards a growing list of today's most compelling embedded devices.

Based on VxWorks.

Extreme Networks, USA

Designed for servers, mainframes, and workstations but can be installed on desktop computers for testing as well.

SUSE, Germany

Network operating system for the Nexus-series Ethernet switches and MDS-series Fibre Channel storage area network switches made by Cisco Systems.

Cisco, USA

Phone Operating system for the Oxo mobile device based on Nucleos OS.

IXI Mobile, USA

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

Minimalist OS fitting on a boot sector of a floppy.

Experimental microkernel used to construct flexible embedded systems inspired by famous L4 microkernel.

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

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

Genesi, USA

Linux distribution for iPAQ machines and other personal digital assistants (PDAs), intended as a replacement for Windows CE on these machines.

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

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

Cisco Systems, USA

Train of Cisco Systems' widely deployed Internetworking Operating System.

Cisco Systems, USA

Train of Cisco Systems' widely deployed Internetworking Operating System (IOS), used on their high-end Network Converging System (NCS), carrier-grade routers.

Cisco Systems, USA

Real-time kernel.

STMicrosystems, Canada

See Baget RTOS.

Russian Academy of Sciences, Russia

Real-time operating system (RTOS) designed to run on micro-controllers for use in sensor networks.

Carnegie-Mellon University, USA

Real-time kernel.

STMicrosystems, Canada

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

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.

DOS extender that adds Unix like multi-user capabilities. Version 3.0 will be DPMI compliant and will use a new portable microkernel named 'BABy'.

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

Russian Academy of Sciences, Russia

Kernel for multiplexing virtual machines.

University of Washington, USA

Cooperative multitasking real-time operating system for Microchip PIC-controllers.

Russia

Russia

Extremely compact OS with GUI, written entirely in FASM assembly language.

Ville M. Turjanmaa, Finland

BS2000 ported to an emulation on a Sun SPARC platform.

Fujitsu-Siemens, Japan

TAJ is India's first object oriented operating system. Its developed in C++. The code is well modularised & maintain. TAJ is a multitasking, multithreading and multiuser operating system.

Viral Patel, India

New Version of this Multiuser DOS, originally introduced in 1984, The design of VMiX has changed to allow it to migrate from IA32 architectures to the newer AMD64 and IA64 environments.

SysDev, USA

Suite of five POSIX Compliant Real Time Operating Systems that are individually optimized for each TI DSP family.

Blackhawk, 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.

Operating system kernel for ARM microcontrollers.

Poland

Free DOS like Operating System which fits on one floppy disk. The new Micro OS X is the third generation of Micro OS. The Micro OS X Workspace Manager is based on GEM Desktop.

Bjoern Schnackenbeck, Germany

Open source scalable real-time operating system for embedded devices.

RT-Thread, China

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.

Real-time application interface. Real-time extension for the Linux kernel, which lets users write applications with strict timing constraints for Linux.

Politecnico di Milano, Italy

Based on oCos. See Lepton.

Philippe Le Boulanger, France

Illumos based platform (Solaris).

Discontinued operating system distribution built using the OpenSolaris source base.

India

Toolkit for building systems for invisible computing and embedded web services.

Microsoft, USA

Real-time operating system designed for embedded systems.

Develer, BeRTOS community, Italy

Hard realtime real-time operating system microkernel that runs the entire Linux operating system as a fully preemptive process. The hard real-time property makes it possible to control robots, data acquisition systems, manufacturing plants, and other time-sensitive instruments and machines from RTLinux applications.

New Mexico Institute of Mining and Technology, USA

A 32-bit multiprocess OS.

A fun os!

jicama, China

Embedded real time operating system designed to be POSIX compliant.

fentISS, Spain

Object-oriented C++ RTOS for microcontrollers.

Formerly Damn Small Solaris. Small size Live CD based on OpenSolaris.

Alexander Eremin, Russia

Embedded, component-based operating system and platform for low-power wireless devices, such as those used in wireless sensor networks (WSNs), smartdust, ubiquitous computing, personal area networks, building automation, and smart meters.

Real-time operating system.

Force10 Networks, USA

Open source OS with an emphasis on design and portability; it is largely implemented in C/C++, with a small amount of assembly. NewOS kernel is used by Haiku OS.

Travis Geiselbrecht, USA

Pseudo real-time OS for gaming console.

Open source real-time operating system for embedded devices.

Bernard Xiong & RT-Thread Team, China

Linux-based real-time OS.

National Instruments, USA

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

ETH Zurich, Switzerland

Aka 1FCD-OpBSD. One Floppy OpenBSD MP3 Player.

Juraj Sipos, Slovakia

Deterministic Real-Time Operating System designed for ARM and Cortex-M devices. Now part of Arm Holding.

Keil Elektronik, Germany

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

Baigudin Software, Russia

Compact and fast real-time kernel for embedded 32/16 bits microprocessors.

Russia

Modular real-time extension for Windows, which combines hardware-dependent programming, communication, automation protocols and image processing into a powerful real-time system.

Kithara Software, Germany

compact and very fast real-time kernel for the embedded 32/16/8 bits microprocessors.

Yuri Tiomkin, Russia

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

Daniel Zorychta, Poland

Embedded operating system designed for running multiple concurrent, mutually distrustful applications on low-memory and low-power microcontrollers.

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

Preemptive or cooperative scheduling RTOS for microcontrollers.

Jim Tremblay, Canada

Scalable RTOS for embedded systems. Based on OSEK RTOS specification (OSEK-VDX).

Argentina ?

Real-Time Operating System provides real-time performance within a small, configurable footprint. The RTOS is tightly integrated with the latest 32-bit MCUs and MPUs from Freescale. See MQX.

NXP Semiconductors, Netherlands

FreeBSD based operating system for system administrators. It contains software for hardware tests, file system check, security check and network setup and analysis.

Ukraine

Kid Operating System (KOS) - A French operating system project. A modular OS, written in C, with an object oriented driver management. Use protected mode. Lots of documentation on the Web site.

Free Operating Systems for Tiny Embedded Devices.

Complementary version of FreeRTOS, with common functionality but designed specifically for safety-critical implementation.

Wittenstein High Integrity Systems, Real Time Engineers Ltd., UK

Single address-space (SAS) OS with orthogonal persistence.

Based on a concept of persistent virtual memory, and is managed-code oriented. Phantom OS is one of a few OSes that are not based on classical concepts of Unix-like systems.

Warsaw University of Technology, Poland

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

Proprietary OS for Casio Pocket Viewer.

Casio, Japan