1. GROUP 3 ITE 229 OPERATING SYSTEM (Non – Proprietary) Table 2 and 3 GROUP LEADER: Jeffrey D. Mangguerra GROUP MEMBERS: Valencia Christian B. Remillete Richard Manggis Nasser A. Adofina Richard Dominic A.

2. TUNIS TUNIS ( T oronto Uni versity S ystem) was a Unix-like operating system , developed at the University of Toronto in the early 1980s. TUNIS was a mostly compatible clone of Unix V7 , but with a completely redesigned kernel , written in Concurrent Euclid . TUNIS targeted the PDP-11 and Motorola 6809 and 68000 architectures

3. MINIX MINIX (sometimes written as Minix ) is a small, open source UNIX clone that was first released in January 1987. It is now best known for its role in inspiring Linus Torvalds to develop Linux .

4. Plan 9 from Bell Labs Plan 9 from Bell Labs is a distributed operating system , primarily used for research. It was developed as the research successor to Unix by the Computing Sciences Research Center at Bell Labs between the mid-1980s and 2002. Plan 9 is most notable for representing all system interfaces, including those required for networking and the user-interface, through the filesystem rather than specialized interfaces. Plan 9 aims to provide users with a workstation-independent working environment through the use of the 9P protocols. Plan 9 continues to be used and developed in some circles as a research operating system and by hobbyists. The name "Plan 9 from Bell Labs" is a reference to the 1959 cult science fiction B-movie Plan 9 from Outer Space .

5. Plan B Plan B is an operating system designed to work in distributed environments where the set of available resources is different at different points in time. Its 4th edition is implemented as a set of user programs to run on top of Plan 9 from Bell Labs. It's main design guidelines are: All resources are perceived as volumes. A volume is a file tree exported to the network together with a name and constraints. The system operates on both local and remote boxes through the same protocol. Any implementor of such protocol can be used as part of a Plan B system. Each application has its own name space and can customize it. Customization is done by defining names for volumes and specifying the desired order and constraints to tailor automatic import of network volumes. Applications try to avoid connections to resources, by using calls that accept file names instead of file descriptors. Volumes can be advertised as they become available to be automatically bound to pre-specified names in the name spaces of applications that care about such resources.

6. The design owes much to Plan 9 and to Off++ . For a description of the system, you may read some of the papers listed in the papers page . You can take a look to a Plan B screenshot and see the code for an example application, the player we use to listen to music within our smart space shown in the screenshot. The player is similar to one implemented for a single machine, but Plan B makes it adapt to device availability and distribute its UI among available screens. The manual for the system can be read here . Some demonstrations for the system are available in the LS main page.

7. Inferno (operating system)

8. Inferno Inferno is an operating system for creating and supporting distributed services. It was based on the experience of Plan 9 from Bell Labs , and the further research of Bell Labs into operating systems, languages, on-the-fly compilers, graphics, security, networking and portability.

9. Design principles Inferno was first made in 1995 by members of Bell Labs ' Computer Science Research division to bring ideas of Plan 9 from Bell Labs to a wider range of devices and networks. Inferno is a distributed operating system based on three basic principles drawn from Plan 9: Resources as files: all resources are represented as files within a hierarchical file system Namespaces: the application view of the network is a single, coherent namespace that appears as a hierarchical file system but may represent physically separated (locally or remotely) resources Standard communication protocol: a standard protocol, called Styx , is used to access all resources, both local and remote

10. Solaris is a Unix -based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS . Solaris is known for its scalability , especially on SPARC systems, as well for being the origin for many innovative features such as DTrace and ZFS . [1] [2] Solaris supports SPARC-based and x86 -based workstations and servers from Sun and other vendors, with efforts underway to port to additional platforms. Solaris is certified against the Single Unix Specification . Although it was historically developed as proprietary software , it is supported on systems manufactured by all major server vendors, and the majority of its codebase is now open source software via the OpenSolaris project. Solaris (operating system)

11. SSS-PC Developed at Tokyo University SSS-PC project team developped the next generation operating system ` SSS-PC ' (pronounced `three ess pc') Ver. 1.0 which runs on personal computers (PC). SSS-PC is being developped at Information Science Laboratory, Ltd. and will be released as its main product in the future. SSS-PC is the dependable scalable operating system feturing unique new technologies such as Memory Based Communication Facility (MBCF) and Information Disclosure Mechanism (IDM) in addition to basic kernel functions such as memory protection and multitasking. SSS-PC has task migration functionality and a unique scheduling system based on Free Marked Mechanism (FMM) and lets users perform maintenance jobs such as machine replacement, hardware component inspection and dynamic system reconfiguration without stopping running applications. The project team is working hard to alpha release SSS-PC by the end of 2003. The project team will reinforce SSS-PC with high dependable features to make it a foundation platform of dependable computing.

12. Features of SSS-PC The features of SSS-PC are explained here . It contains the following topics. Memory-Based Communication Facilities: MBCF Task migration Free Market Mechanism scheduling: FMM Information Disclosure Mechanism: IDM Linux/UNIX compatible program development environment Distributed Shared Memory: UDSM/ADSM Optimizing compiler: RCOP OS kernel: Micro Core Miscellaneous

13. Unix Unix (officially trademarked as UNIX, sometimes also written as Unix with small caps ) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs , including Ken Thompson , Dennis Ritchie , Douglas McIlroy , and Joe Ossanna . Today's Unix systems are split into various branches, developed over time by AT&T as well as various commercial vendors and non-profit organizations.

14. Xinu (" X inu I s N ot U nix", a recursive acronym ) is a Unix-like operating system originally developed by Douglas Comer for instructional purposes at Purdue University in the 1980s. It has been ported to many hardware platforms, including the DEC LSI-11 and VAX systems, Sun-2 and Sun-3 workstations, Intel x86 , PowerPC G3 and MIPS . Xinu has been deployed in several commercial products, and continues to be used for operating system and networking courses at Universities around the world.

15. Berkeley Software Distribution Berkeley Software Distribution (BSD, sometimes called Berkeley Unix) is the Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley , from 1977 to 1995. Historically, BSD has been considered a branch of UNIX — "BSD UNIX", because it shared the initial codebase and design with the original AT&T UNIX operating system. In the 1980s, BSD was widely adopted by vendors of workstation -class systems in the form of proprietary UNIX variants such as DEC ULTRIX and Sun Microsystems SunOS . This can be attributed to the ease with which it could be licensed, and the familiarity it found among the founders of many technology companies of this era. Though these commercial BSD derivatives were largely superseded by the UNIX System V Release 4 and OSF/1 systems in the 1990s (both of which incorporated BSD code), later BSD releases provided a basis for several open source development projects which continue to this day. Today, the term of "BSD" is often non-specifically used to refer to any of these BSD descendants, e.g. FreeBSD , NetBSD or OpenBSD , which together form a branch of the family of Unix-like operating systems.

16. GNU is a computer operating system composed entirely of free software . Its name is a recursive acronym for GNU's Not Unix ; it was chosen because its design is Unix-like , but differs from Unix by being free software and containing no Unix code. [1] Development of GNU was initiated by Richard Stallman and was the original focus of the Free Software Foundation (FSF). GNU is developed by the GNU Project , and programs released under the auspices of the project are called GNU packages or GNU programs . The system's basic components include the GNU Compiler Collection (GCC), the GNU Binary Utilities (binutils), the bash shell, the GNU C library (glibc), and GNU Core Utilities (coreutils).

17. Linux Linux (commonly pronounced IPA: /ˈlɪnəks/ in English; variants exist) is a generic term referring to Unix-like computer operating systems based on the Linux kernel . Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed by anyone under the terms of the GNU GPL and other free licenses. Linux distributions are predominantly known for their use in servers , although they are installed on a wide variety of computer hardware , ranging from embedded devices and mobile phones to supercomputers , and their popularity as a desktop/laptop operating system has been growing lately due to the rise of netbooks and the Ubuntu distribution of the operating system. The name "Linux" comes from the Linux kernel , originally written in 1991 by Linus Torvalds . The rest of the system, including utilities and libraries , usually comes from the GNU operating system announced in 1983 by Richard Stallman . The GNU contribution is the basis for the alternative name GNU/Linux

18. Darwin (operating system) Darwin is an open source POSIX -compliant computer operating system released by Apple Inc. in 2000. It is composed of code developed by Apple, as well as code derived from NEXTSTEP , FreeBSD , and other free software projects. Darwin forms the core set of components upon which Mac OS X and iPhone OS are based. It is compatible with the Single UNIX Specification version 3 (SUSv3) and POSIX UNIX applications and utilities

19. Solaris (operating system) Solaris is a Unix -based operating system introduced by Sun Microsystems in 1992 as the successor to SunOS . Solaris is known for its scalability , especially on SPARC systems, as well for being the origin for many innovative features such as DTrace and ZFS . [1] [2] Solaris supports SPARC-based and x86 -based workstations and servers from Sun and other vendors, with efforts underway to port to additional platforms. Solaris is certified against the Single Unix Specification . Although it was historically developed as proprietary software , it is supported on systems manufactured by all major server vendors, and the majority of its codebase is now open source software via the OpenSolaris project

20. Syllable Desktop (operating system) Syllable is a free and open source operating system for Pentium and compatible processors. Its purpose is to create an easy-to-use desktop operating system for the home and small office user. It was forked from the stagnant AtheOS in July 2002. It has a native web browser ( ABrowse which is WebKit -based), email client (Whisper), media player, IDE , and many more applications. Features according to the official website include: Native 64-bit journaled file system , the AtheOS File System (usually called AFS , which is not the same as the Andrew File System ) C++ oriented API Object-oriented graphical desktop environment on a native GUI architecture Mostly POSIX compliant Software ports , including Emacs , Vim , Perl , Python , Apache and others. GNU toolchain ( GCC , Glibc , Binutils , Make ) Pre-emptive multitasking with multithreading Symmetric multiprocessing (multiple processor ) support Device drivers for most common hardware (video, sound, network chips) File system drivers for FAT (read/write), NTFS (read) and ext2 (read) REBOL as system scripting language The latest version is 0.6.5, released on January 8 , 2008 .

21. VSTa VSTa (Valencia's Simple Tasker) was an operating system with a microkernel architecture, with all device drivers and file systems residing in userspace mode. It is mostly POSIX compliant, except when POSIX compatibility got in the way of extensibility and modularity. It was conceptually inspired by QNX and Plan 9 . Written by Andy Valencia , and released under the GPL license. Currently the licensing for VSTa is Copyleft . VSTa was originally written to run on i386 hardware, but was subsequently ported to several different platforms, e.g. 68030 based Amigas . VSTa is no longer developed, but its ideas and source code are being used in the FMI/OS operating system, which continues the cause of VSTa.

22. Research non-Unix-like

23. AMOEBA The Amoeba project is a research effort aimed at understanding how to connect multiple computers in a seamless way [16, 17, 26, 27, 31]. The basic idea is to provide the users with the illusion of a single powerful timesharing system, when, in fact, the system is implemented on a collection of machines, potentially distributed among several countries.

24. CROQUET The Croquet Project is an international effort to promote the continued development of Croquet, a free software platform and a network operating system for developing and delivering deeply collaborative multi-user online applications . Croquet was specifically designed to enable the creation and low-cost deployment of large scale metaverses .

25. House Haskell User's Operating System and Environment, research OS written in Haskell and C. House is an acronym for the Haskell User's Operating System and Environment . It is an experimental operating system written in Haskell . It was written to explore system programming in a functional programming language . It includes a graphical user interface , several demos, and its network protocol stack provides basic support for Ethernet , IPv4 , ARP , DHCP , ICMP (ping), UDP , TFTP , and TCP .

26. ILIOS ILIOS is an acronym of I nter L ink I nternet O perating S ystem. It is an attempt to create a router -only operating system ; one specifically oriented towards computer networking purposes, especially routing . It supports IPv4 routing and is a good educational OS, though it is single tasking and does everything via interrupts. It is released under the BSD License . The author of this research OS is Rink Springer, who is also responsible for porting FreeBSD to the Xbox

27. EROS microkernel, capability-base EROS ( The Extremely Reliable Operating System ) is an operating system developed by The EROS Group, LLC., the Johns Hopkins University , and the University of Pennsylvania . Interesting features include automatic data and process persistence , some preliminary real-time support, and capability-based security . EROS is purely a research operating system, and was never deployed in real world use. As of 2005, development has stopped in favor of two successor systems, CapROS and Coyotos

28. L4 Second generation microkernel L4 is a family of second-generation microkernels based on the original designs and implementations by German computer scientist Jochen Liedtke . Originally implemented in highly tuned Intel i386 -specific assembly language code, the API has seen extensive development in a number of directions, both in achieving a higher grade of platform independence and also in improving security , isolation, and robustness . There have been various re-implementations of the original binary L4 kernel interface ( ABI ) and its higher level successors, including L4Ka::Pistachio ( Uni Karlsruhe ), L4/MIPS ( UNSW ) and Fiasco ( TU Dresden ). For this reason, the name L4 has been generalized and no longer only refers to Liedtke's original implementation. It now applies to the whole microkernel family including the L4 kernel interface and its different versions.

29. Mach (from OS kernel research at Carnegie Mellon University Mach is an operating system microkernel developed at Carnegie Mellon University to support operating system research, primarily distributed and parallel computation. It is one of the earliest examples of a microkernel, and still the standard by which similar projects are measured.

30. MONADS capability-based OS designed to support the MONADS hardware projects A Monads-PC Computer A Monads-PC Computer The Monads Project was initiated by Prof. Keedy in 1976 at Monash University in Melbourne, Australia. It became an ongoing "umbrella" project for a variety of related research activities concerned with the design of computer systems, in particular in the areas of computer hardware and architecture, operating systems, distributed systems, and practical software engineering research. It was continued at the Universities of Newcastle (NSW) and of Sydney in Australia, and at the Technical University of Darmstadt and at the Universities of Bremen and of Ulm in Germany. For further details see the history of the project below. The Monads project led to the design of several computer processors, some of which were also built and used in practice. These are described in more detail below under the heading of Monads Computers.

31. Self-Paging in the Nemesis Operating System Steven M. Hand University of Cambridge Computer Laboratory New Museums Site, Pembroke St., Cambridge CB2 3QG, ENGLAND [email_address] In contemporary operating systems, continuous media (CM) applications are sensitive to the behaviour of other tasks in the system. This is due to contention in the kernel (or in servers) between these applications. To properly support CM tasks, we require ``Quality of Service Firewalling'' between different applications. This paper presents a memory management system supporting Quality of Service (QoS) within the Nemesis operating system. It combines application-level paging techniques with isolation, exposure and responsibility in a manner we call self-paging . This enables rich virtual memory usage alongside (or even within) continuous media applications.

32. Singularity - A research operating system written mostly in managed code ( C# ) by Microsoft Singularity is an experimental operating system being built by Microsoft Research since 2003. It is intended as a highly- dependable OS in which the kernel , device drivers , and applications are all written in managed code Singularity is a microkernel operating system. Unlike most historical microkernels, its components execute in the same address space ( process ), which contains "software-isolated processes" (SIPs). Each SIP has its own data and code layout, and is independent from other SIPs. These SIPs behave like normal processes, but avoid the cost of task-switches.

33. Spring (research OS from Sun Microsystems) Spring was an experimental microkernel -based object oriented operating system developed at Sun Microsystems in the early 1990s. Using technology substantially similar to concepts developed in the Mach kernel , Spring concentrated on providing a richer programming environment supporting multiple inheritance and other features. Spring was also more cleanly separated from the operating systems it would host, divorcing it from its Unix roots and even allowing several OSes to be run at the same time. Development faded out in the mid-1990s, but several ideas and some code from the project was later re-used in the Java programming language libraries and the Solaris operating system .

34. V from Stanford, early 1980s The V operating system (sometimes written V-System , not to be confused with System V ) is a microkernel operating system that was developed by faculty and students in the Distributed Systems Group at Stanford University in the 1980s, led primarily by Prof. David Cheriton . V was the successor to the Thoth and Verax operating systems that Cheriton had worked on previously. The original V terminology uses "process" for what is now commonly called a " thread ", and "team" for what is now commonly called a " process " consisting of multiple threads sharing an address space, but this article will use modern terminology.

35. Open Source non-Unix-like

36. FullPliant (programming language based) In computer software programming languages history, Pliant is the first attempt to connect C and LISP branches. It was written by Hubert Tonneau, first published in 1999, and is released under GNU General Public License version 2. Objective Bring raw efficiency and high expressivity at once. Selected solution Focus on program encoding as opposed to language features. Principles Pliant is based on two main main concepts: First, the program is successively encoded in four precisely defined models: *Source code *Expressions tree *Instructions list *Executable Then, the three transitions between these four models can freely be changed at application level because the compiler is dynamic and reflexive .

37. FreeDOS (open source DOS variant) FreeDOS (formerly Free-DOS and PD-DOS ) is an operating system for IBM PC compatible computers. FreeDOS is made up of many different, separate programs that act as "packages" to the overall FreeDOS Project. As a member of the DOS family, it provides mainly disk access through its kernel , and partial memory management , but no default GUI (although OpenGEM is listed on the official FreeDOS website). FreeDOS is currently at version 1.0, released on September 3 , 2006 . FreeDOS supports vintage hardware IBM PC as well as modern ones, in addition to embedded computers . Unlike MS-DOS , it is composed of free and open source software , licensed under the terms of the GNU General Public License (GPL). It does not require license fees or royalties and creation of custom distributions is permitted.However, in its "util" section it includes also non-free software such as 4DOS .

38. FreeVMS (open source VMS variant) FreeVMS is a free software clone of VMS computer operating system , licensed under the terms of the GNU General Public License . As of 2008, the project is in the early stages of development. The latest version is 0.3.11. It consists of a kernel (planned to be POSIX -compliant[ citation needed ]) and a DCL command line interpreter On the contrary to the traditional target architectures of VMS systems — VAX , Alpha and IA-64 — FreeVMS supports only i386 processors.

39. Haiku (open source inspired by BeOS , under development) Haiku , formerly known as OpenBeOS [1] , is a free and open source software project dedicated to the re-creation and continuation of BeOS on x86 and PowerPC based computers.

40. Development Haiku is developed in C++ and provides an object-oriented API. BeOS’s modular design has enabled teams of volunteer programmers to work independently on replacements for individual servers and APIs (collectively known in Haiku as “kits”). These teams include: App/Interface – develops the Interface, App and Support kits. BFS – develops the Be File System , which is mostly complete with the resulting OpenBFS Game – develops the Game Kit and its APIs. Input Server – the server that handles input devices, such as keyboards and mice and how they communicate with other parts of the system. Kernel – develops the kernel , the core of the operating system. Media – develops the audio server and related APIs. MIDI – implements the MIDI protocol. Network – writes drivers for network devices and APIs relating to networking. OpenGL – develops OpenGL support. Preferences – recreates BeOS’s preferences suite. Printing – works on the print servers and drivers for printers. Screen Saver – implements screen saver functionality. Storage – develops the storage server and drivers for required filesystems. Translation – recreates the reading/writing/conversion modules for the different file formats. A few kits have been deemed feature complete and the rest are in various stages of development. Haiku’s kernel is a modular hybrid kernel and a fork of NewOS [2] , a modular kernel written by former Be Inc. engineer Travis Geiselbrecht. Like the rest of the system it is currently still under heavy development. Many features have been implemented, including a virtual file system (VFS) layer and rudimentary symmetric multiprocessing (SMP) support.

41. ReactOS ( free software Windows NT compatible OS, in early development since 2001) ReactOS is a computer operating system intended to be binary compatible with application software and device drivers made for Microsoft Windows NT versions 5.x and up ( Windows 2000 and its successors). It is composed entirely of free software , by means of a complete clean room reverse engineering process. Although the project is in the alpha development stage as of 2009, many Windows programs already work well. While the ReactOS kernel has been written from scratch, the userland is based on the Wine compatibility layer for Unix-like operating systems . ReactOS is primarily written in the C programming language , with some elements, such as ReactOS Explorer, written in C++ . Various components of ReactOS are licensed under the GNU General Public License , the GNU Lesser General Public License and the BSD License

42. Development FreeWin95 to ReactOS Around 1996 a group of free and open source software developers started a project called FreeWin95 , to implement a clone of Windows 95 . The project stalled in discussions of the design of the system. At the end of 1997 the project had yet to release any software. The project members, led by coordinator Jason Filby, got together to revive the project. The project's target was changed to Windows NT and the project's name was changed to ReactOS . The ReactOS project began in February 1998, started by developing the kernel and basic drivers.

43. ReactOS project coordinator Aleksey Bragin (left) shows ReactOS functionality to Viktor Alksnis . ReactOS's many APIs and ABIs are ready for a higher level of development and a basic GUI is available. ReactOS features ReactOS Explorer (ROSExplorer), a basic shell similar to Windows Explorer . 0.2 Alpha version 0.2.0 of ReactOS, released in March 2004, is able to run many Win32 applications, including Notepad (a basic text editor), Regedit (the Registry editor), cmd.exe (the command-line interpreter), and several other applications (such as AbiWord ) and some older games (such as Quake and Quake II , and the Wine clone of Minesweeper ). Some games like Unreal Tournament and Deus Ex are confirmed to work, using software rendering . OpenGL runs with some minor problems, using the nVidia driver or the software implementation Mesa 3D . The first Web server ( Tiny Web Server ) [1] and VNC client ( UltraVNC ) are reported to work, and OpenOffice.org version 1.x works partly. Version 0.2.2 , released on April 28, 2004, has basic bugfixes and feature improvements Version 0.2.5 , released on January 5, 2005, has large improvements in networking and stability. In version 0.2.8 some elements of TCP/IP networking work, as well as a larger number of applications. Sound and USB support is still being worked on ( SB16 works partially, and USB OHCI and UHCI work is still being undertaken). The USB functionality is derived from the Cromwell project. Plug-and-play work has also begun, as has the move to support the Windows Driver Model . In addition to the Lynx text-based browser, ReactOS can use DCOM components from Mozilla to browse web pages graphically. ReactOS 0.2.8 can also detect whether it is running in a VMware environment and can install the SVGA driver from the VMware Tools ISO to provide a better level of GUI performance. CSRSS has also been totally rewritten, and a "written-from-scratch" implementation of Winsock 2 is scheduled to arrive very soon. Also present in the trunk are somewhat-working elements of ddraw, dplay, and dplayx.

44. 0.3 ReactOS 0.3.0 Release Candidate 1 was released on June 15, 2006. It is also an alpha build. Improved network (TCP/IP) and Plug & Play support are the headline improvements of this version. Version 0.3.0 Release Candidate 2 was released when the audit reached 94%. It was deemed appropriate to release another candidate version at this time because so many bug fixes had been made during the audit. ReactOS 0.3.1 , released on March 11, 2007, was the first release after the start of a massive kernel rewrite, which made many parts more compatible to NT 5.2. This release also features the addition of a Registry library, which greatly improved the Registry support. An easy tool for downloading popular free and Shareware applications also debuted in this release. Version 0.3.2 had been skipped due to many complex blockers, which could not be fixed in the scheduled time frame. The release of ReactOS 0.3.3 on September 12, 2007 brought more improvements in the kernel, bringing many areas closer to NT 5.2. It also brought stability increase in many core modules, especially win32k. ReactOS 0.3.4 , released on January 22, 2008, brought a rewrite of registry support, syncing of DLLs with the Wine project, improved plug'n'play support, improvements to user32, Win32k, many core user mode components, shell32, the Control Panel, and the addition of a remote desktop client. [2] Version 0.3.5 was released on June 30, 2008, contains fixes for many old bugs, some having been present since 0.3 or even earlier and some being regressions introduced in further releases due to rewrites of certain components. [3] Version 0.3.6 , released on August 6, 2008, also contains bug fixes in the kernel and a RTL heap implementation. Note: Unlike stated in the news entry on the website this release does not contain the initial AMD64 support (currently being developed in a separate branch). [4] Version 0.3.7 was released on November 4, 2008; it contains improved support for the x64 architecture and the start of a real MSVC compiler support. This version also includes many bug fixes and new stacks (like network). [5] 0.4 Version 0.4 is expected to have a 50% compatible Windows NT Kernel, SMB support, initial audio support, Winlogon, support for USB input devices, support for the 5 most common network cards, and networking improvement. 0.5 Version 0.5 will be marked as beta rather than alpha

45. osFree (open source OS/2 implementation) OS/2 is a computer operating system , initially created by Microsoft and IBM , then later developed by IBM exclusively. The name stands for "Operating System/2," because it was introduced as part of the same generation change release as IBM's " Personal System/2 (PS/2)" line of second-generation personal computers . OS/2 is no longer marketed by IBM, and IBM standard support for OS/2 was discontinued on 31 December 2006. [1] Currently, Serenity Systems sells OS/2 under the brand name eComStation . OS/2 was intended as a protected mode successor of PC-DOS . Notably, basic system calls were modeled after MS-DOS calls; their names even started with "Dos" and it was possible to create "Family Mode" applications: text mode applications that could work on both systems.Because of this heritage, OS/2 is like Windows in many ways, but it also shares similarities with Unix and Xenix . IBM made a deal with Commodore to license Amiga technology for OS/2 2.0 and above in exchange for the REXX scripting language. This means OS/2 may have code not written by IBM, which can prevent the OS from being open sourced in the future.