Operating Systems

Operating Systems (OSes) reviewed.

All Microkernel-based OSes.

All Unix OSes.

See also Systems Code Resources.

2K - Formerly known as SPINE, is a distributed, reflexive, component-based, adaptable OS
a-kernel - Was a project to determine if AOP can be used to improve OS modularity, and thereby reduce complexity and fragility associated with system implementation
AdaOS - A project to create a new fully distributed OS, written mostly in Ada
Aegis - An exokernel based OS
Agnix - Agnix is a 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
Alliance OS - 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
AmigaOS - A commercial OS originally developed for the Motorola 68k based Commodore Amiga line of computers - now owned by Amiga, Inc
Amoeba - Andy Tanenbaum's microkernel OS with multiple servers, allowing parallel (transparent to the user) execution, resource sharing, and more; the reference among distributed OSes
Apertos - Sony CSL's Apertos, a Reflexive OO OS, also described in Spanish
Apostle - Apostle OS
Argon - Alaric B
AROS - AROS, the Amiga Research OS project, lead by Aaron Digulla is rewriting a free software clone of AmigaOS from scratch, hoping to fix bugs and legal problems with the original OS, and finally port it away from the deceased (until further notice) Amiga hardware platform to the i386 PC (already complete) and other platforms (PPC, Alpha, whatever)
AtheOS - AtheOS is a heavily multithreaded OS, written from scratch, that supports SMP, TCP/IP, a fast GUI, and most of the useful POSIX functionality
BeOS - Be, Inc
BOS - An acronym for Bubach Operating System, apparently a no-kernel OS
BRiX - Brand Huntsman's BRiX OS will be based on modular functions that can be dynamically called by other functions
BSD - The BSD family used to be the reference for Unix-like OSes
BugOS - An impressive OS project for a single author
Cache Kernel - From Kenneth Duda homepage, one of the authors:
chaOS - chaOS, 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
Charm - The Charm Operating System is a nano-kernel OS aimed at the support of Orthogonal Persistence
Choices - Choices, an OO OS in C++ (yuck!)
Chorus - A 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...)
Contiki - From its home page (see below):
coyotos - A capability-based OS, the successor to EROS; it will be implemented in a low-level language with clean semantics, BitC
CP/M - An early OS for microcomputer by Gary Kildall of Digital Research for Intel 8080 and Zilog Z80 based 8-bit computers
Denali - Denali is a kernel for multiplexing virtual machines
Dolphin - Samuel A
DOS - The colloquial name for MS-DOS, an early operating system produced and sold by Microsoft
DR DOS - DR DOS (or DR-DOS) is an OS, a free-for-non-commercial-use version of DOS; was once released as OpenDOS, but Caldera reverted to the historical name
DragonFlyBSD - A Unix-like OS of the BSD family
eCos - eCos from Red Hat (was from Cygnus Solutions), an OS runtime compatible with the japanese norm µITron, with complete source code available, and FREE
EduOS - Frank Cornelis's EduOS is a small OS that was being written for educational purposes and for the x86 architecture
EOS - Was an OS specially designed to run games under
EROS - Extremely Reliable Operating System, is a small, secure (capability-based), real-time OS that provides orthogonal persistence
EUMEL - Extendable multiUser Microprocessor ELan system, was an OS by Jochen Liedtke, with persistent processes and data spaces, built to offer a standalone environment for the educational programming language ELAN
Exokernel - A OS project from MIT
FlexOS - Another little OS designed for developing experience and fun
Forth OSes - The idea for a modern Forth OS has been kicking around since maybe 1995
Fox - The Fox project from CMU to write an OS using (an extension to) the programming language Standard ML
FreeBSD - FreeBSD (a successor of 386BSD) is a Unix-like OS, mostly for the Intel and Alpha platforms and is most up-to-date among BSDs regarding device drivers
FreeDOS - FreeDOS is an OS, a free DOS clone, based on Pat Villani's DOS-C kernel
Freedows - Reece Sellin's Freedows (SourceForge project) is an OS that would be binary-compatible with multiple existing OSes including Windows
FreeRTOS - An open source (free), portable, preemptive, real-time OS kernel (RTOS scheduler) aimed at small real time embedded systems
FunOS - A mostly-functional OS, written in Scheme, at http://www.sarg.ryerson.ca/funos/
Geex! - Fabricio Rocha's Geex! OS, where the philosophy is to make an OS with a very small footprint, working on old computers, and completely free
Genera - Genera is the OS that runs on Symbolics Lisp Machines; it also runs under hardware emulators for Mac, and under a software emulator on 64-bit Alpha machines
GEOS - GRAPHIC ENVIRONMENT OPERATING SYSTEM is some very fine OO OS for various kinds of computers (including old 8-bit), that comes with a GUI and various office applications
GNUStep - A Unix-like OS, a project to implement a free clone of NeXTStep
GO! - An OS, by Greg Law, based on the idea of building an entire Operating System from software components (based on CORBA and its ORB) that can be replaced and recycled; it also introduces an x86-specific security model based on segmentation and code scanning (an example of a no-kernel system)
Grasshopper - Grasshopper is a distributed OS with Orthogonal Persistence
Haiku - Haiku is a desktop OS that will be binary-compatible with BeOS R5
Hello - Hello is a prototype OS in Standard ML done at University of Hawaii
hOp - A microkernel OS based on the Run Time System (RTS) of GHC, an Haskell implementation
HURD - The GNU HURD is the GNU project's replacement for the Unix OS kernel
Iguana - Iguana from the Coyote project at Dublin Trinity College, an OO, reflexive OS supporting MOPs, distribution, and runtime reconfiguration in order to meet changes in non-functional requirements (ie. dynamic customisation)
Inferno - A networked OS from Vita Nuova and its Limbo language, successor of Plan9 (from Bell Labs), the system that reinvented scoping for coarse-grained objects
ITS - ITS (Incompatible Timesharing System) was a famous OS developed by hackers at MIT's AI lab from 1967 to the early 1980's for the DEC PDP-6 and PDP-10 family
JANOS - JANOS is Java-Oriented Active Network OS
JeniOS - MIA JeniOS is a project of an OS usable by anyone
JOS - This project wants to create a free, open OS based on the Java� technology, ie
KallistiOS - KallistiOS is pseudo real-time OS for gaming console
KangaroOS - Redhog's KangaroOS, an OS implementing multitasking by providing a VM to each process; processes can also have subprocesses that they can schedule at their liking
KeyKOS - A persistent, pure capability OS, generally a nano-kernel design
KML - Kernel Mode Linux is a Linux OS variant which execute user
Knewcleus - Ralph Gerlich's Knewcleus is a 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
KnowOS - Knowledge Operating System (KnowOS) is a project for a dynamic system with persistent objects
KOS - KOS is a small project of developing an OS being worked on by a few French people
L4 - A family of OSes originally by Jochen Liedtke are microkernels to demonstrate how optimizing performance requires OS kernels to be completely hardware-dependent, and even CPU-version dependent in a same family of CPUs
Linux - Linux is a free UNIX� compliant OS implementation written by Linus Torvalds and lots of people on the Internet
LispOS - LispOS was a project to revive the still unequalled systems that ran on Lisp Machines of the past (such as the still surviving Genera) this time making it free and running on standard/cheap hardware, instead of proprietary and requiring non-standard/expensive hardware
Lites - Lites is a Unix-like OS of the BSD family as a "singleserver" over the Mach microkernel
LittleOS - LittleOS is a small OS experiment being developed by a group of individuals
LOS - Jonas Berlin's MIA LOS was meant to be another OS for gamers, like EOS
Mac OS X - MacOS X, the next version of Apple's highly proprietary OS, was not based on the Copland development project, but on a cross with NeXTStep called Rhapsody (which up to Dev release 2 was available for PCs), and is designed to have the friendly MacOS graphical layer over 4
Mach - Mach is a free microkernel upon which many experimental OSes are built
MachTen - MachTen is a Unix-like OS, a commercial version of 4
MacOS - Apple's old proprietary OS for its Macintosh 68k and PowerPC platforms
MenuetOS - MenuetOS is a tiny OS fully developed in assembly
Merlin - Jecel's Merlin project of a Self-based OS (and a papers about it)
MetaOS - An OS model
Microsoft Windows - Microsoft Windows is a name which refers to a series of OSes from Microsoft
Milan - Milan the OS
Minix - Minix is Andy Tanenbaum's famous Unix-like educational OS in 2 versions:
ML/OS - An experimental OS kernel, developed in the context of The Express project run by Olin Shivers, constructed by porting the SML/NJ implementation of Standard ML to run on a bare PC through the OSKit library for the low-level machine management
MorphOS - MorphOS OS is a new OS based on the Quark microkernel
Moscow - Julian R
Movitz - It is a Common Lisp OS development platform
Multics - Multics is the "great" OS (written in PL/I) whose design began in the late 60's, co-written by MIT, AT&T Bell Labs and GE, that was meant to become the be-all- end-all of OS technology by having just every (un)imaginable feature, and that was supplanted by Unix, despite the fact that Multics was much better(?) designed, because Unix' simple and stubborn design was much more adapted to the very resource-poor architectures of the time
Multipop - An OS, by Robin Popplestone, first operational in late 1967, which was based on the concurrently developed implemenation of POP-2; Multipop employed no conventional hardware protection mechanisms: its security was guaranteed by accessing system resources via closures of device access functions, and on built in restrictions on code generation embodied in the compiler (an ancient example of a no-kernel system)
Multiuser DOS - An OS, a commercial DOS clone by Concurrent Controls
Mungi - Mungi is the OS project that originally proposed a one global distributed shared memory, aka a single address space or SAS (starting with 64-bit virtual address space)
M�bius - M�bius is an OS
NASOS - Not Another Scheme OS
NetBSD - NetBSD is a Unix-like OS of the BSD family which focuses on portability and networking and supports tens of platforms
NewOs - An open source OS with an emphasis on design and portability; it is largely implemented in C/C++, with a small amount of assembly
Newton OS - Apple's Newton OS was interesting
NitrOS-9 - NitrOS-9 is basically a reconstruction of OS-9 for the 6809 Tandy CoCo3, but refined for the Hitachi 6309 compatible CPU
NOW - NOW (at Berkeley) is
NTDIOS - NTDIOS Networ Disk OS is a working 32-bit, multitasking, OS for x86-based computers, running in protected mode
O/OS - Frank Kudermann's O/OS [MIA] introduces a new GUI concept, and aims at architecturing the OS around reusable, replacable components
Off - Off and its successor Off++ are distributed microkernel OSes that transparently migrate light-weight processes ("shuttles") over the network, communicating by distributed IPC ("Portals"), in a one global distributed shared memory space
OJOS - OJOS (the Original J Operating System), aka Platypus is an OS which
OKE - OKE, the Open Kernel Environment, is an extension to the Linux OS which allows users other than root to load native and fully optimised code in the kernel
Opal - The Opal project, yet another distributed single (wide) address space (SAS) OS with page-level protection, implemented on top of Mach on Alphas
OpenBLT - Brian J
OpenBSD - OpenBSD is a Unix-like OS of the BSD family, has split from NetBSD, and focuses on stability and security
OS-9 - RadiSys's (was Microware) OS-9 is real-time OS (RTOS), widely used, and still in good shape after so many years
OS161 - OS/161 is an instructional OS produced for an undergraduate introductory operating system concepts at Harvard, by the same group of VINO
OSKit - A complete modular infrastructure that provides all the "bricks" (resources) needed to easily build an OS, focusing on what interests you, and reusing components for the rest
OZONE - An object-oriented OS primarily based on VMS with the use of the GNU toolchain, and Unix-style pipes (also using record-oriented pipes, a VMS feature called a "mailbox")
Pegasus - Pegasus and Pegasus II, 2 OSes from the University of Cambridge, whose purpose is to support applications requiring a constant quality of service QoS
PETROS - An OS, it will (would) be a Microsoft Windows clone programmed in a proprietary Object Pascal, by Trumpet Software International (producer of the famous Trumpet Winsock)
Phantom OS - Balazs Miklos's Phantom OS MIA is a project for an OS for x86 PCs, based on a microkernel, and released under the GNU General Public License
Plan B - An OS designed to work in distributed environments where the set of available resources (a single abstraction, the box) is different at different points in time
Plan9 - Plan9 OS, or what Unix should have been (originally by Bell Labs from where Unix came)
Platform OS - Joel Utting's ("Platform OS" | http://www.geocities.com/SiliconValley/Pines/7674/opsys.html) MIA is an OS wanted to achieve platform-independence through a low-level VM
Plurix - An integrated environment (OS/programming language combination) based on Java with a custom native code compiler for x86, an orthogonal persistent Distributed Shared Memory (DSM) for PC clusters, with a consistency model based on restartable transactions coupled with an optimistic synchronization scheme
Proolix - Prool's Proolix is an OS, yet another Unix clone project for the old 8086 PCs, from former USSR
PTS-DOS - PTS-DOS is an OS, a (commercial) DOS clone from Russia (fast mirror in USA)
Puma - Puma OS at Sandia National Laboratories with a distributed memory architectures
QNX - QNX
QuickOS - A really-quick-realtime-multitasking OS
Raven - MIA (Raven | http://www.angelfire.com/az/ravenos/) is another attempt at making an OS for x86 PCs from scratch
ReactOS - Jason Filby's ReactOS project, aiming to produce a free Windows NT 4
Real32 - An OS, a commercial DOS clone by Intelligent Micro Software
Retro - Tom Novelli's original "Retro" was a FORTH-based OS and a prototype low-level infrastructure for the TUNES project
RISC OS - RISC OS is the nifty OS that runs on (defunct?) Acorn's ARM-based RISC PC (now RiscStation)
rojan - Was SamOS
ROM-DOS - An OS, a commercial DOS clone by Datalight
ROME - Research OS for Multimedia Engineering
rtmk - A free real-time microkernel OS developed by Johan Rydberg, sharing alot of ideas with Mach
RxDOS - An OS, a (commercial) DOS clone as described and available in the author's book "Dissecting DOS"
Sanos - Sanos is an OS kernel for use in PC based server appliances
schemix - Schemix is an implementation of (a subset of) Scheme that runs inside the Linux Kernel OS, so you can dynamically debug your device-drivers
Scout - Scout an OS specifically aimed at network appliances (webcams, ip routers..) from the University of Arizona
ShagOS - Frank Barrus' ShagOS is a (running) OO system based on a message passing kernel
ShawnOS - Brian Klock's ShawnOS is a small OS, written in 3 months entirely in assembly, that is functional enough to run programs
Silk - SILK (Scout in Linux Kernel) is a Linux kernel module which transforms a standard Linux OS into Scout
SkyOS - SkyOS is yet another new OS for x86 PCs
SLK - SLK, the Safe Language Kernel Project is developing an OS infrastructure for extensible systems
Sombrero - Sombrero is an OS providing an unique address to objects in a global address space (SAS), much like Mungi
Space - (lost in) SPACE from University of Santa Barbara, which implements an OS with a protection as multiple layers, rather than the classic kernel-user scheme
SPIN - SPIN OS from University of Washington, which allows applications to migrate code in kernel space, implementing new functionality or replacing default policies
Spoon - An OS based on a microkernel
Spring - A project to create an improved OS
Sprite - The Sprite distributed OS from UCB (project terminated, but still some useful information there)
Stella - An OS by Tony Tebby, one of the fathers of modern personal computers whose fame mostly comes from having created the Sinclair QL (Quantum Leap) computer and its MC68000-based, multitasking, graphical operating system in the early 80's, even before the Amiga
Sting - From its home page:
SwarmOS - MIA (SwarmOS | http://members.tripod.com/~swarmOS/) is a pretty standard, kernel based OS, but that actually boots and works to some extent
Syllable - An OS, a fork of AtheOS
Symbian - Symbian, formerly known as EPOC32, the OS at the heart of PSION hardware and an increasing number of telephony, telecommunication, PDA, etc
Synthesis - Henry Massalin's Synthesis kernel, the first of the modern OS that dynamically generated code at runtime
Synthetix - OGI's Synthetix project of fine-grained incremental partial evaluation in OS kernels, using a combination of highly isolated system components, and dynamic code generation
Tao OS - An OS
THix - A deceased project of a Unix OS implementation written from scratch for the purpose of learning
Tigger - Was a project to develop an OS and framework for the construction of a family of distributed object-oriented platforms
Topsy - Topsy is an educational OS developed at ETZH
Torsion - A single address-space (SAS) OS with orthogonal persistence at http://www.torsion.org
Tripos - An OS
TrustedBSD - A 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)
TSX-32 - TSX-32 is a 32-bit (commercial) OS for PCs with small memory requirements that can also emulate DOS (and run Windows?)
UCSD P-Code - Was a concrete VM of historical note as an early OS for some microcomputers; it was based on Pascal's operational model, and implemented in UCSD Pascal - which was also the most used language on the platform
Unix - UNIX � is the worldwide Single UNIX
Unununium - The Unununium, aka Uuu, "operating engine" is "a highly componentized system, where each component can be dynamically loaded, unloaded, replaced at runtime
V2_OS - V2_OS by the V2 Lab in Netherlands
Vapour - A project to build out a Lisp-based OS based on a persistent object store and has quite a few other interesting principles
VINO - VINO (at Harvard)
VSTa - Andy Valencia's VSTa
VxWorks - Wind River's VxWorks and Tornado real-time OS (RTOS), microkernel based, POSIX and ANSI C language compliant
Xen - Xen is a virtualisation kernel to which Linux has been ported, NetBSD and XP are being ported, such that you can run as many of each of these OSs (and others if they are ported or written) on a single box
XOberon/PowerPC - From its home page:
Xok - Xok (developed by MIT LCS Parallel and Distributed OSes group)
Zot OS - Zot OS is a small free OS with a GUI

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