OS/2 (Operating System/2) is a series of computer

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

s, initially created by

Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washin ...

and IBM under the leadership of IBM software designer

Ed Iacobucci Edward E. Iacobucci (September 26, 1953 – June 21, 2013) was an Argentine-American businessman who founded VirtualWorks and co–founded Citrix Systems. He is also known for his work as the architectural designer of the OS/2 and IBM DOS syst ...

. As a result of a feud between the two companies over how to position OS/2 relative to Microsoft's new

Windows 3.1 Windows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series ran as a shell on top of MS-DOS. Codenamed Janus, Windows 3 ...

operating environment, the two companies severed the relationship in 1992 and OS/2 development fell to 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 The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART (serial p ...

(PS/2)" line of second-generation

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

s. The first version of OS/2 was released in December 1987 and newer versions were released until December 2001. OS/2 was intended as a

protected-mode In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as virtual memory, paging and safe multi-tasking d ...

successor of PC DOS. Notably, basic

system call In computing, a system call (commonly abbreviated to syscall) is the programmatic way in which a computer program requests a service from the operating system on which it is executed. This may include hardware-related services (for example, acc ...

s were modeled after

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few ope ...

calls; their names even started with "Dos" and it was possible to create "Family Mode" applications –

text mode Text mode is a computer display mode in which content is internally represented on a computer screen in terms of characters rather than individual pixels. Typically, the screen consists of a uniform rectangular grid of ''character cells'', each ...

applications that could work on both systems. Because of this heritage, OS/2 shares similarities with

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, an ...

Xenix Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and ...

, and

Windows NT Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system. The first version of Win ...

. IBM discontinued its support for OS/2 on 31 December 2006. Since then, OS/2 has been developed, supported and sold by two different third-party vendors under license from IBM – first by Serenity Systems as

eComStation eComStation or eCS is an operating system based on OS/2 Warp for the 32-bit x86 architecture. It was originally developed by Serenity Systems and Mensys BV under license from IBM. It includes additional applications, and support for new hard ...

since 2001, and later by Arca Noae LLC as ArcaOS since 2017.

Development history

1985–1989: Joint development

The development of OS/2 began when IBM and Microsoft signed the "Joint Development Agreement" in August 1985. It was code-named "CP/DOS" and it took two years for the first product to be delivered. OS/2 1.0 was announced in April 1987 and released in December. The original release was

textmode Text mode is a computer display mode in which content is internally represented on a computer screen in terms of characters rather than individual pixels. Typically, the screen consists of a uniform rectangular grid of ''character cells'', each ...

-only, and a GUI was introduced with OS/2 1.1 about a year later. OS/2 features an

API An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how ...

for controlling the

video display A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...

(VIO) and handling

keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Musi ...

and mouse events so that programmers writing for protected mode need not call the BIOS or access hardware directly. Other development tools included a subset of the video and keyboard APIs as linkable libraries so that family mode programs are able to run under MS-DOS, and, in the OS/2 Extended Edition v1.0, a database engine called Database Manager or DBM (this was related to DB2, and should not be confused with the

DBM DBM or dbm may refer to: Science and technology * dBm, a unit for power measurement * DBM (computing), family of key-value database engines including dbm, ndbm, gdbm, and Berkeley DB * Database Manager (DBM), a component of 1987's ''Extended Edi ...

family of database engines for Unix and

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

operating systems). A task-switcher named Program Selector was available through the Ctrl-Esc

hotkey computing, a keyboard shortcut also known as hotkey is a series of one or several keys to quickly invoke a software program or perform a preprogrammed action. This action may be part of the standard functionality of the operating system or ...

combination, allowing the user to select among multitasked text-mode sessions (or screen groups; each can run multiple programs). Communications and database-oriented extensions were delivered in 1988, as part of OS/2 1.0 Extended Edition: SNA,

X.25 X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts ...

/ APPC/LU 6.2,

LAN Manager LAN Manager is a discontinued network operating system (NOS) available from multiple vendors and developed by Microsoft in cooperation with 3Com Corporation. It was designed to succeed 3Com's 3+Share network server software which ran atop a h ...

, Query Manager, SQL. The promised user interface,

Presentation Manager Presentation Manager (PM) is the graphical user interface (GUI) that IBM and Microsoft introduced in version 1.1 of their operating system OS/2 in late 1988. History Microsoft began developing a graphic user interface (GUI) in 1981. After it per ...

, was introduced with OS/2 1.1 in October 1988. It had a similar user interface to

Windows 2.1 Windows 2.1 is a major release of Microsoft Windows. It was released to manufacturing on May 27, 1988, as a successor to Windows 2.0. It was released with two different variants with differing CPU compatibility, also known as Windows/286 and ...

, which was released in May of that year. (The interface was replaced in versions 1.2 and 1.3 by a look closer in appearance to

Windows 3.0 Windows 3.0 is the third major release of Microsoft Windows, launched in 1990. It features a new graphical user interface (GUI) where applications are represented as clickable icons, as opposed to the list of file names seen in its predeces ...

). The Extended Edition of 1.1, sold only through IBM sales channels, introduced distributed database support to IBM database systems and SNA communications support to IBM mainframe networks. In 1989, Version 1.2 introduced Installable Filesystems and, notably, the HPFS

filesystem In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is Computer data storage, stored and retrieved. Without a file system, data placed in a storage me ...

. HPFS provided a number of improvements over the older

FAT In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

file system, including long filenames and a form of alternate data streams called

Extended Attributes Extended file attributes are file system features that enable users to associate computer files with metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as permissions or ...

. In addition, extended attributes were also added to the FAT file system. The Extended Edition of 1.2 introduced

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

and

Ethernet Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1 ...

support. OS/2- and Windows-related books of the late 1980s acknowledged the existence of both systems and promoted OS/2 as the system of the future.

1990: Breakup

The collaboration between IBM and Microsoft unravelled in 1990, between the releases of

and OS/2 1.3. During this time, Windows 3.0 became a tremendous success, selling millions of copies in its first year. Much of its success was because Windows 3.0 (along with MS-DOS) was bundled with most new computers. OS/2, on the other hand, was available only as an additional stand-alone software package. In addition, OS/2 lacked device drivers for many common devices such as printers, particularly non-IBM hardware. Windows, on the other hand, supported a much larger variety of hardware. The increasing popularity of Windows prompted Microsoft to shift its development focus from cooperating on OS/2 with IBM to building its own business based on Windows. Several technical and practical reasons contributed to this breakup. The two companies had significant differences in culture and vision. Microsoft favored the open hardware system approach that contributed to its success on the PC. IBM sought to use OS/2 to drive sales of its own hardware, and urged Microsoft to drop features, such as

fonts In metal typesetting, a font is a particular size, weight and style of a typeface. Each font is a matched set of type, with a piece (a " sort") for each glyph. A typeface consists of a range of such fonts that shared an overall design. In mod ...

, that IBM's hardware did not support. Microsoft programmers also became frustrated with IBM's bureaucracy and its use of

lines of code Source lines of code (SLOC), also known as lines of code (LOC), is a software metric used to measure the size of a computer program by counting the number of lines in the text of the program's source code. SLOC is typically used to predict the am ...

to measure programmer productivity. IBM developers complained about the terseness and lack of comments in Microsoft's code, while Microsoft developers complained that IBM's code was bloated. The two products have significant differences in API. OS/2 was announced when Windows 2.0 was near completion, and the

Windows API The Windows API, informally WinAPI, is Microsoft's core set of application programming interfaces (APIs) available in the Microsoft Windows operating systems. The name Windows API collectively refers to several different platform implementations th ...

already defined. However, IBM requested that this API be significantly changed for OS/2. Therefore, issues surrounding application compatibility appeared immediately. OS/2 designers hoped for source code conversion tools, allowing complete migration of Windows application source code to OS/2 at some point. However, OS/2 1.x did not gain enough momentum to allow vendors to avoid developing for both OS/2 and Windows in parallel. OS/2 1.x targets the

Intel 80286 The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non- multiplexed address and data buses and also the ...

processor and DOS fundamentally does not. IBM insisted on supporting the 80286 processor, with its 16-bit

segmented memory Memory segmentation is an operating system memory management technique of division of a computer's primary memory into segments or sections. In a computer system using segmentation, a reference to a memory location includes a value that identifi ...

mode, because of commitments made to customers who had purchased many 80286-based PS/2s as a result of IBM's promises surrounding OS/2. Until release 2.0 in April 1992, OS/2 ran in 16-bit protected mode and therefore could not benefit from the

Intel 80386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors32-bit

flat memory model Flat memory model or linear memory model refers to a memory addressing paradigm in which "memory appears to the program as a single contiguous address space." The CPU can directly (and linearly) address all of the available memory locations witho ...

and

virtual 8086 mode In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a ...

features. This was especially painful in providing support for DOS applications. While, in 1988, Windows/386 2.1 could run several cooperatively multitasked DOS applications, including

expanded memory In DOS memory management, expanded memory is a system of bank switching that provided additional memory to DOS programs beyond the limit of conventional memory (640 KiB). ''Expanded memory'' is an umbrella term for several incompatible tec ...

(EMS) emulation, OS/2 1.3, released in 1991, was still limited to one "DOS box". Given these issues, Microsoft started to work in parallel on a version of Windows which was more future-oriented and more portable. The hiring of

Dave Cutler David Neil Cutler Sr. (born March 13, 1942) is an American software engineer. He developed several computer operating systems, namely Microsoft's Windows NT, and Digital Equipment Corporation's RSX-11M, VAXELN, and VMS. Personal history Cu ...

, former

VAX/VMS OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Ope ...

architect, in 1988 created an immediate competition with the OS/2 team, as Cutler did not think much of the OS/2 technology and wanted to build on his work on the MICA project at Digital rather than creating a "DOS plus". His NT OS/2 was a completely new architecture. IBM grew concerned about the delays in development of OS/2 2.0. Initially, the companies agreed that IBM would take over maintenance of OS/2 1.0 and development of OS/2 2.0, while Microsoft would continue development of OS/2 3.0. In the end, Microsoft decided to recast NT OS/2 3.0 as

, leaving all future OS/2 development to IBM. From a business perspective, it was logical to concentrate on a consumer line of operating systems based on DOS and Windows, and to prepare a new high-end system in such a way as to keep good compatibility with existing Windows applications. While it waited for this new high-end system to develop, Microsoft would still receive licensing money from Xenix and OS/2 sales. Windows NT's OS/2 heritage can be seen in its initial support for the

HPFS filesystem HPFS (High Performance File System) is a file system created specifically for the OS/2 operating system to improve upon the limitations of the FAT file system. It was written by Gordon Letwin and others at Microsoft and added to OS/2 version 1 ...

, text mode OS/2 1.x applications, and OS/2 LAN Manager network support. Some early NT materials even included OS/2 copyright notices embedded in the software. One example of NT OS/2 1.x support is in the WIN2K resource kit. Windows NT could also support OS/2 1.x

and AVIO applications with the addition of the Windows NT Add-On Subsystem for Presentation Manager.

1992: 32-bit era

OS/2 2.0 was released in April 1992. At the time, the suggested retail price was , while Windows retailed for . OS/2 2.0 provided a 32-bit API for native programs, though the OS itself still contained some 16-bit code and drivers. It also included a new OOUI (object-oriented user interface) called the

Workplace Shell The Workplace Shell (WPS) is an object-oriented desktop shell (also called desktop environment) produced by IBM's Boca Raton development lab for OS/2 2.0. It is based on Common User Access and made a radical shift away from the Program Manager ...

. This was a fully object-oriented interface that was a significant departure from the previous GUI. Rather than merely providing an environment for program windows (such as the Program Manager), the Workplace Shell provided an environment in which the user could manage programs, files and devices by manipulating objects on the screen. With the Workplace Shell, everything in the system is an "object" to be manipulated.

DOS compatibility

OS/2 2.0 was touted by IBM as "a better DOS than DOS and a better Windows than Windows". It managed this by including the fully-licensed MS-DOS 5.0, which had been patched and improved upon. For the first time, OS/2 was able to run more than one DOS application at a time. This was so effective, that it allowed OS/2 to run a modified copy of Windows 3.0, itself a

DOS extender A DOS extender is a computer software program running under DOS that enables software to run in a protected mode environment even though the host operating system is only capable of operating in real mode. DOS extenders were initially develope ...

, including Windows 3.0 applications. Because of the limitations of the

processor, OS/2 1.x could run only one DOS program at a time, and did this in a way that allowed the DOS program to have total control over the computer. A problem in DOS mode could crash the entire computer. In contrast, OS/2 2.0 could leverage the

of the

Intel 80386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

in which to run DOS programs. This included an extensive set of configuration options to optimize the performance and capabilities given to each DOS program. Any real-mode operating system (such as 8086

) could also be made to run using OS/2's virtual machine capabilities, subject to certain direct hardware access limitations. Like most 32-bit environments, OS/2 could not run protected-mode DOS programs using the older

VCPI In computing, the Virtual Control Program Interface (VCPI) is a specification published in 1989 by Phar Lap Software that allows a DOS program to run in protected mode, granting access to many features of the processor not available in real mode ...

interface, unlike the Standard mode of Windows 3.1; it only supported programs written according to DPMI. (Microsoft discouraged the use of VCPI under Windows 3.1, however, due to performance degradation.) Unlike Windows NT, OS/2 always allowed DOS programs the possibility of masking real hardware interrupts, so any DOS program could

deadlock In concurrent computing, deadlock is any situation in which no member of some group of entities can proceed because each waits for another member, including itself, to take action, such as sending a message or, more commonly, releasing a loc ...

the machine in this way. OS/2 could, however, use a hardware

watchdog Watchdog or watch dog may refer to: Animals *Guard dog, a dog that barks to alert its owners of an intruder's presence * Portuguese Watch Dog, Cão de Castro Laboreiro, a dog breed * Moscow Watchdog, a breed of dog that was bred in the Soviet ...

on selected machines (notably IBM machines) to break out of such a deadlock. Later, release 3.0 leveraged the enhancements of newer Intel 80486 and

Intel Pentium Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and P ...

processors—the Virtual Interrupt Flag (VIF), which was part of the

Virtual Mode Extensions In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a ...

(VME)—to solve this problem.

Windows 3.x compatibility

Compatibility with Windows 3.0 (and later Windows 3.1) was achieved by adapting Windows user-mode code components to run inside a

virtual DOS machine Virtual DOS machines (VDM) refer to a technology that allows running 16-bit/32-bit DOS and 16-bit Windows programs when there is already another operating system running and controlling the hardware. Overview Virtual DOS machines can operate eit ...

(VDM). Originally, a nearly complete version of Windows code was included with OS/2 itself: Windows 3.0 in OS/2 2.0, and Windows 3.1 in OS/2 2.1. Later, IBM developed versions of OS/2 that would use whatever Windows version the user had installed previously, patching it on the fly, and sparing the cost of an additional Windows license. It could either run full-screen, using its own set of video drivers, or "seamlessly," where Windows programs would appear directly on the OS/2 desktop. The process containing Windows was given fairly extensive access to hardware, especially video, and the result was that switching between a full-screen WinOS/2 session and the Workplace Shell could occasionally cause issues. Because OS/2 only runs the user-mode system components of Windows, it is incompatible with Windows device drivers (

VxD VxD is the device driver model used in Microsoft Windows/386 2.x, the 386 enhanced mode of Windows 3.x, Windows 9x, and to some extent also by the Novell DOS 7, OpenDOS 7.01, and DR-DOS 7.02 (and higher) multitasker (TASKMGR). VxDs have acc ...

s) and applications that require them. Multiple Windows applications run by default in a single Windows session – multitasking cooperatively and without memory protection – just as they would under native Windows 3.x. However, to achieve true isolation between Windows 3.x programs, OS/2 can also run multiple copies of Windows in parallel, with each copy residing in a separate VDM. The user can then optionally place each program either in its own Windows session – with preemptive multitasking and full memory protection ''between'' sessions, though not ''within'' them – or allow some applications to run together cooperatively in a shared Windows session while isolating other applications in one or more separate Windows sessions. At the cost of additional hardware resources, this approach can protect each program in any given Windows session (and each instance of Windows itself) from every other program running in any ''separate'' Windows session (though not from other programs running in the same Windows session). Whether Windows applications are running in full-screen or windowed mode, and in one Windows session or several, it is possible to use DDE between OS/2 and Windows applications, and OLE between Windows applications only. IBM's OS/2 for Windows product (codename Ferengi), also known as "OS/2, Special Edition", was interpreted as a deliberate strategy "of cashing in on the pervasive success of the Microsoft platform" but risked confusing consumers with the notion that the product was a mere accessory or utility running on Windows such as Norton Desktop for Windows when, in fact, it was "a complete, modern, multi-tasking, pre-emptive operating system", itself hosting Windows instead of running on it. Available on CD-ROM or 18 floppy disks, the product documentation reportedly suggested Windows as a prerequisite for installing the product, also being confined to its original FAT partition, whereas the product apparently supported the later installation of Windows running from an HPFS partition, particularly beneficial for users of larger hard drives. Windows compatibility, relying on patching specific memory locations, was reportedly broken by the release of Windows 3.11, prompting accusations of arbitrary changes to Windows in order to perpetrate "a deliberate act of Microsoft sabotage" against IBM's product.

1994: OS/2 Warp

Released in 1994, OS/2 version 3.0 was labelled as OS/2 Warp to highlight the new performance benefits, and generally to freshen the product image. "Warp" had originally been the internal IBM name for the release: IBM claimed that it had used '' Star Trek'' terms as internal names for prior OS/2 releases, and that this one seemed appropriate for external use as well. At the launch of OS/2 Warp in 1994,

Patrick Stewart Sir Patrick Stewart (born 13 July 1940) is an English actor who has a career spanning seven decades in various stage productions, television, film and video games. He has been nominated for Olivier, Tony, Golden Globe, Emmy, and Screen Actors ...

was to be the Master of Ceremonies; however

Kate Mulgrew Katherine Kiernan Maria Mulgrew (born April 29, 1955) is an American actress and author. She is best known for her roles as Captain Kathryn Janeway on '' Star Trek: Voyager'' and Red on ''Orange Is the New Black''. She first came to attention ...

of the then-upcoming series '' Star Trek: Voyager'' substituted for him at the last minute. OS/2 Warp offers a host of benefits over OS/2 2.1, notably broader hardware support, greater multimedia capabilities,

Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...

-compatible networking, and it includes a basic office application suite known as

IBM Works IBM Works is an office suite for the IBM OS/2 operating system. It includes word processing, spreadsheet, database and PIM applications. Originally developed as Legato by IBM UK, it was later taken over by Footprint in Canada, also known as Fo ...

. It was released in two versions: the less expensive "Red Spine" and the more expensive "Blue Spine" (named for the color of their boxes). "Red Spine" was designed to support Microsoft Windows applications by utilizing any existing installation of Windows on the computer's hard drive. "Blue Spine" includes Windows support in its own installation, and so can support Windows applications without a Windows installation. As most computers were sold with Microsoft Windows pre-installed and the price was less, "Red Spine" was the more popular product. OS/2 Warp Connect—which has full LAN client support built-in—followed in mid-1995. Warp Connect was nicknamed "Grape". In OS/2 2.0, most performance-sensitive subsystems, including the graphics (Gre) and multimedia (MMPM/2) systems, were updated to 32-bit code in a fixpack, and included as part of OS/2 2.1. Warp 3 brought about a fully 32-bit windowing system, while Warp 4 introduced the object-oriented 32-bit GRADD display driver model.

1996: Warp 4

In 1996, Warp 4 added

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

and

speech recognition Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the ...

software. IBM also released server editions of Warp 3 and Warp 4 which bundled IBM's LAN Server product directly into the operating system installation. A personal version of

Lotus Notes HCL Notes (formerly IBM Notes and Lotus Notes; see Branding below) and HCL Domino (formerly IBM Domino and Lotus Domino) are the client and server Server may refer to: Computing *Server (computing), a computer program or a device that provide ...

was also included, with a number of template databases for contact management, brainstorming, and so forth. The UK-distributed free demo CD-ROM of OS/2 Warp essentially contained the entire OS and was easily, even accidentally,

cracked Cracked may refer to: Television * ''Cracked'' (British TV series), a 2008 British comedy-drama television series that aired on STV * ''Cracked'' (Canadian TV series), a 2013 Canadian crime drama series that aired on CBC * "Cracked", a Season 8 ( ...

, meaning that even people who liked it did not have to buy it. This was seen as a backdoor tactic to increase the number of OS/2 users, in the belief that this would increase sales and demand for third-party applications, and thus strengthen OS/2's desktop numbers. This suggestion was bolstered by the fact that this demo version had replaced another which was not so easily cracked, but which had been released with trial versions of various applications. In 2000, the July edition of '' Australian Personal Computer'' magazine bundled software CD-ROMs, included a full version of Warp 4 that required no activation and was essentially a free release. Special versions of OS/2 2.11 and Warp 4 also included symmetric multiprocessing (SMP) support. OS/2 sales were largely concentrated in networked computing used by corporate professionals; however, by the early 1990s, it was overtaken by Microsoft

. While OS/2 was arguably technically superior to Microsoft

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturi ...

, OS/2 failed to develop much penetration in the consumer and stand-alone desktop PC segments; there were reports that it could not be installed properly on IBM's own

Aptiva The IBM Aptiva personal computer was introduced in September 1994 as the replacement for the IBM PS/1. The first Aptiva models were based on the Intel 80486 CPU with later models using the Pentium and AMD CPUs. All systems were developed in-hou ...

series of home PCs. Microsoft made an offer in 1994 where IBM would receive the same terms as

Compaq Compaq Computer Corporation (sometimes abbreviated to CQ prior to a 2007 rebranding) was an American information technology company founded in 1982 that developed, sold, and supported computers and related products and services. Compaq produced ...

(the largest PC manufacturer at the time) for a license of Windows 95, if IBM ended development of OS/2 completely. IBM refused and instead went with an "IBM First" strategy of promoting OS/2 Warp and disparaging Windows, as IBM aimed to drive sales of its own software as well as hardware. By 1995, Windows 95 negotiations between IBM and Microsoft, which were already difficult, stalled when IBM purchased

Lotus SmartSuite Lotus may refer to: Plants *Lotus (plant), various botanical taxa commonly known as lotus, particularly: ** ''Lotus'' (genus), a genus of terrestrial plants in the family Fabaceae **Lotus flower, a symbolically important aquatic Asian plant also ...

, which would have directly competed with

Microsoft Office Microsoft Office, or simply Office, is the former name of a family of client software, server software, and services developed by Microsoft. It was first announced by Bill Gates on August 1, 1988, at COMDEX in Las Vegas. Initially a marketi ...

. As a result of the dispute, IBM signed the license agreement 15 minutes before Microsoft's Windows 95 launch event, which was later than their competitors and this badly hurt sales of IBM PCs. IBM officials later conceded that OS/2 would not have been a viable operating system to keep them in the PC business.

Workplace OS

In 1991, IBM started development on an intended replacement for OS/2 called

Workplace OS Workplace OS is IBM's ultimate operating system prototype of the 1990s. It is the product of an exploratory research program in 1991 which yielded a design called the Grand Unifying Theory of Systems (GUTS), proposing to unify the world's system ...

. This was an entirely new product, brand new code, that borrowed only a few sections of code from both the existing OS/2 and AIX products. It used an entirely new microkernel code base, intended (eventually) to host several of IBM's operating systems (including OS/2) as microkernel "personalities". It also included major new architectural features including a system registry, JFS, support for UNIX graphics libraries, and a new driver model. Workplace OS was developed solely for POWER platforms, and IBM intended to market a full line of PowerPCs in an effort to take over the market from

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

. A mission was formed to create prototypes of these machines and they were disclosed to several corporate customers, all of whom raised issues with the idea of dropping Intel. Advanced plans for the new code base would eventually include replacement of the

OS/400 IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS ...

operating system by Workplace OS, as well as a microkernel product that would have been used in industries such as telecommunications and set-top television receivers. A partially functional pre-alpha version of Workplace OS was demonstrated at Comdex, where a bemused

Bill Gates William Henry Gates III (born October 28, 1955) is an American business magnate and philanthropist. He is a co-founder of Microsoft, along with his late childhood friend Paul Allen. During his career at Microsoft, Gates held the positions ...

stopped by the booth. The second and last time it would be shown in public was at an OS/2 user group in Phoenix, Arizona; the pre-alpha code refused to boot. It was released in 1995. But with $990 million being spent per year on development of this as well as Workplace OS, and no possible profit or widespread adoption, the end of the entire Workplace OS and OS/2 product line was near.

Downsizing

A project was launched internally by IBM to evaluate the looming competitive situation with Microsoft Windows 95. Primary concerns included the major code quality issues in the existing OS/2 product (resulting in over 20 service packs, each requiring more diskettes than the original installation), and the ineffective and heavily matrixed development organization in Boca Raton (where the consultants reported that "basically, everybody reports to everybody") and Austin. That study, tightly classified as "Registered Confidential" and printed only in numbered copies, identified untenable weaknesses and failures across the board in the Personal Systems Division as well as across IBM as a whole. This resulted in a decision being made at a level above the Division to cut over 95% of the overall budget for the entire product line, end all new development (including Workplace OS), eliminate the Boca Raton development lab, end all sales and marketing efforts of the product, and lay off over 1,300 development individuals (as well as sales and support personnel). $990 million had been spent in the last full year. Warp 4 became the last distributed version of OS/2.

2001: Fading out

Although a small and dedicated community remains faithful to OS/2, OS/2 failed to catch on in the mass market and is little used outside certain niches where IBM traditionally had a stronghold. For example, many bank installations, especially automated teller machines, run OS/2 with a customized user interface; French SNCF national railways used OS/2 1.x in thousands of ticket selling machines. Telecom companies such as Nortel used OS/2 in some voicemail systems. Also, OS/2 was used for the host PC used to control the Public Radio Satellite System, Satellite Operations Support System equipment installed at National Public Radio, NPR member stations from 1994 to 2007, and used to receive the network's programming via satellite. Although IBM began indicating shortly after the release of Warp 4 that OS/2 would eventually be withdrawn, the company did not end support until December 31, 2006. Sales of OS/2 stopped on December 23, 2005. The latest IBM OS/2 Warp version is 4.52, which was released for both desktop and server systems in December 2001. IBM is still delivering defect support for a fee. IBM urges customers to migrate their often highly complex applications to Electronic business, e-business technologies such as

in a platform-neutral manner. Once application migration is completed, IBM recommends migration to a different operating system, suggesting Linux as an alternative.

Third-party development

After IBM discontinued development of OS/2, various third parties approached IBM to take over future development of the operating system. The OS/2 software vendor Stardock made such a proposal to IBM in 1999, but it was not followed through by the company.Dan Casey
OS/2 Voice Press Release
- 21 Sept 1999. Serenity Systems succeeded in negotiating an agreement with IBM, and began reselling OS/2 as eComStation in 2001. eComStation is now sold by XEU.com, the most recent version (2.1) was released in 2011. In 2015, Arca Noae, LLC announced that they had secured an agreement with IBM to resell OS/2. They released the first version of their OS/2-based operating system in 2017 as ArcaOS. As of 2021, there have been multiple releases of ArcaOS, and it remains under active development.

Petitions for open source

Many people hoped that IBM would release OS/2 or a significant part of it as open-source software, open source. Petitions were held in 2005 and 2007, but IBM refused them, citing legal and technical reasons. It is unlikely that the entire OS will be open at any point in the future because it contains third-party code to which IBM does not have copyright, and much of this code is from

. IBM also once engaged in a technology transfer with Commodore International, Commodore, licensing Amiga technology for OS/2 2.0 and above, in exchange for the Rexx, REXX scripting language. This means that OS/2 may have some code that was not written by IBM, which can therefore prevent the OS from being re-announced as open-sourced in the future. On the other hand, IBM donated Object REXX for Windows and OS/2 to the ''Open Object REXX'' project maintained by the ''REXX Language Association'' on SourceForge. There was a petition, arranged by OS2World, to open parts of the OS. Open source operating systems such as Linux have already profited from OS/2 indirectly through IBM's release of the improved JFS (file system), JFS file system, which was ported from the OS/2 code base. As IBM didn't release the source of the OS/2 JFS driver, developers ported the Linux driver back to

and added the functionality to boot from a JFS partition. This new JFS driver has been integrated into eComStation v2.0, and later into ArcaOS 5.0.

Summary of releases

Release dates refer to the US English editions unless otherwise noted.

Features and technology

User interface

The graphic system has a layer named Presentation Manager that manages windows, fonts, and icons. This is similar in functionality to a non-networked version of X11 or the Graphics Device Interface, Windows GDI. On top of this lies the

(WPS) introduced in OS/2 2.0. WPS is an object-oriented shell (computers), shell allowing the user to perform traditional computing tasks such as accessing files, printers, launching legacy programs, and advanced object oriented tasks using built-in and third-party application objects that extended the shell in an integrated fashion not available on any other mainstream operating system. WPS follows IBM's Common User Access user interface standards. WPS represents objects such as disks, folders, files, program objects, and printers using the System Object Model (SOM), which allows code to be shared among applications, possibly written in different programming languages. A distributed version called DSOM allowed objects on different computers to communicate. DSOM is based on CORBA. The object oriented aspect of SOM is similar to, and a direct competitor to, Microsoft's Component Object Model, though it is implemented in a radically different manner; for instance, one of the most notable differences between SOM and COM is SOM's support for inheritance (one of the most fundamental concepts of OO programming)—COM does not have such support. SOM and DSOM are no longer being developed. The multimedia capabilities of OS/2 are accessible through Media Control Interface commands. The last update (bundled with the IBM version of Netscape Navigator plugins) added support for MPEG files. Support for newer formats such as Portable Network Graphics, PNG, JPEG, progressive JPEG, DivX, Ogg, and MP3 comes from third parties. Sometimes it is integrated with the multimedia system, but in other offers it comes as standalone applications.

Commands

The following list of command (computing), commands is supported by cmd.exe on OS/2. * ansi (command), ansi * append (command), append * assign (command), assign * attrib * backup (command), backup * boot * break (command), break * cache * call (command), call * cd (command), cd * chcp (command), chcp * cd (command), chdir * chkdsk * cls (command), cls * cmd.exe, cmd * Code page, codepage * COMMAND.COM, command * comp (command), comp * copy (command), copy * createdd * date (command), date * ddinstal * debug (command), debug * del (command), del * detach * dir (command), dir * diskcomp * diskcopy * doskey * dpath * eautil * echo (command), echo * endlocal * del (command), erase * exit (command), exit * extproc * fdisk * fdiskpm * find (Windows), find * for (command), for * format (command), format * fsaccess * goto (command), goto * graftabl * help (command), help * if (command), if * JOIN (command), join * keyb (command), keyb * keys (command), keys * label (command), label * makeini * mkdir, md * mem (command), mem * mkdir * mode (command), mode * more (command), more * move (command), move * patch * path (command), path * pause (command), pause * picview * pmrexx * print (command), print * prompt (command), prompt * pstat * rmdir, rd * recover (command), recover * rem (command), rem * ren (command), ren * ren (command), rename * replace (command), replace * restore (command), restore * rmdir * set (command), set * setboot * setcom40 * setlocal * share (command), share * shift (command), shift * SORT (DOS command), sort * spool * start (command), start * SUBST, subst * syslevel * syslog * TIME (command), time * trace * tracebuf * tracefmt * tree (command), tree * TYPE (DOS command), type * UNDELETE, undelete * unpack * ver (command), ver * verify (command), verify * view * vmdisk * vol (command), vol * xcopy

Networking

The TCP/IP stack is based on the open-source software, open source BSD stack as visible with Source Code Control System, SCCS List of Unix commands, what compatible tools. IBM included tools such as ftp and telnet and even servers for both commands. IBM sold several networking extensions including NFS support and an X11 server.

Drivers

Hardware vendors were reluctant to support device drivers for alternative operating systems including OS/2, leaving users with few choices from a select few vendors. To relieve this issue for video cards, IBM licensed a reduced version of the UniVBE, Scitech display drivers, allowing users to choose from a wide selection of cards supported through Scitech's modular driver design.

Virtualization

OS/2 has historically been more difficult to run in a virtual machine than most other legacy x86 operating systems because of its extensive reliance on the full set of features of the x86 CPU; in particular, OS/2's use of ring (computer security), ring 2 prevented it from running in early versions of VMware. Newer versions of VMware provide official support for OS/2, specifically for eComStation. VirtualPC from

(originally Connectix) has been able to run OS/2 without hardware virtualization support for many years. It also provided "additions" code which greatly improves host–guest OS interactions in OS/2. The additions are not provided with the current version of VirtualPC, but the version last included with a release may still be used with current releases. At one point, OS/2 was a supported host for VirtualPC in addition to a guest. Note that OS/2 runs only as a guest on those versions of VirtualPC that use virtualization (x86 based hosts) and not those doing full emulation (VirtualPC for Mac). VirtualBox from Oracle Corporation (originally InnoTek, later Sun Microsystems, Sun) supports OS/2 1.x, Warp 3 through 4.5, and eComStation as well as "Other OS/2" as guests. However, attempting to run OS/2 and eComStation can still be difficult, if not impossible, because of the strict requirements of VT-x/AMD-V hardware-enabled virtualization and only ACP2/MCP2 is reported to work in a reliable manner. ArcaOS supports being run as a

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

guest inside VirtualBox, VMware ESXi and VMWare Workstation. It ships with VirtualBox Guest Additions, and driver improvements to improve performance as a guest operating system. The difficulties in efficiently running OS/2 have, at least once, created an opportunity for a new Platform virtualization, virtualization company. A large bank in Moscow needed a way to use OS/2 on newer hardware that OS/2 did not support. As virtualization software is an easy way around this, the company desired to run OS/2 under a hypervisor. Once it was determined that VMware was not a possibility, it hired a group of Russian software developers to write a host-based hypervisor that would officially support OS/2. Thus, the Parallels (company), Parallels, Inc. company and their Parallels Workstation product was born.

Security niche

OS/2 has few native computer viruses; while it is not invulnerable by design, its reduced market share appears to have Security through obsolescence, discouraged virus writers. There are, however, OS/2-based antivirus programs, dealing with DOS viruses and Windows viruses that could pass through an OS/2 server.

Problems

Some problems were classic subjects of comparison with other operating systems: *''Synchronous input queue (SIQ)'': if a GUI application was not servicing its ''window messages'', the entire GUI system could get stuck and a reboot was required. This problem was considerably reduced with later Warp 3 fixpacks and refined by Warp 4, by taking control over the application after it had not responded for several seconds. *''No unified object handles (OS/2 v2.11 and earlier)'': The availability of threads probably led system designers to overlook mechanisms which allow a single thread to wait for different types of asynchronous events at the same time, for example the keyboard and the mouse in a "console" program. Even though ''select'' was added later, it only worked on network sockets. In case of a console program, dedicating a separate thread for waiting on each source of events made it difficult to properly release all the input devices before starting other programs in the same "session". As a result, console programs usually polled the keyboard and the mouse alternately, which resulted in wasted CPU and a characteristic "jerky" reactivity to user input. In OS/2 3.0 IBM introduced a new call for this specific problem.

Historical uses

OS/2 has been widely used by Iran Export Bank (Bank Saderat Iran) in their teller machines, ATMs and local servers (over 30,000 working stations). As of 2011, the bank moved to virtualize and renew their infrastructure by moving OS/2 to Virtual Machines running over Windows. OS/2 was widely used by Brazilian banks. Banco do Brasil had a peak 10,000 machines running OS/2 Warp in the 1990s. OS/2 was used in automated teller machines until 2006. The workstations and automated teller machines and attendant computers have been migrated to Linux. Atm os2warp

OS/2 has been used in the banking industry. Suncorp bank in Australia still ran its Automated teller machine, ATM network on OS/2 as late as 2002. ATMs at Perisher Ski Resort, Perisher Blue used OS/2 as late as 2009, and even the turn of the decade. OS/2 was widely adopted by accounting professionals and auditing companies. In mid-1990s native 32-bit accounting software were well developed and serving corporate markets. OS/2 ran the faulty baggage handling system at Denver International Airport. The OS was eventually scrapped, but the software written for the system led to massive delays in the opening of the new airport. The OS itself was not at fault, but the software written to run on the OS was. The baggage handling system was eventually removed. OS/2 was used by radio personality Howard Stern. He once had a 10-minute on-air rant about OS/2 versus

and recommended OS/2. He also used OS/2 on his IBM ThinkPad 760, IBM 760CD laptop. OS/2 was used as part of the Satellite Operations Support System (SOSS) for NPR's Public Radio Satellite System. SOSS was a computer-controlled system using OS/2 that NPR member stations used to receive programming feeds via satellite. SOSS was introduced in 1994 using OS/2 3.0, and was retired in 2007, when NPR switched over to its successor, the Public Radio Satellite System#ContentDepot, ContentDepot. OS/2 was used to control the SkyTrain (Vancouver), SkyTrain automated light rail system in Vancouver, Canada until the late 2000s when it was replaced by Windows XP. OS/2 was used in the London Underground Jubilee Line Extension Signals Control System (JLESCS) in London, England. This control system delivered by Alcatel was in use from 1999 to 2011 i.e. between abandonment before opening of the line's unimplemented original automatic train control system and the present SelTrac system. JLESCS did not provide automatic train operation only manual train supervision. Six OS/2 local site computers were distributed along the railway between Stratford tube station, Stratford and Westminster tube station, Westminster, the shunting tower at Stratford Market Depot, and several formed the central equipment located at Neasden Depot. It was once intended to cover the rest of the line between Green Park tube station, Green Park and Stanmore tube station, Stanmore but this was never introduced. OS/2 has been used by The Co-operative Bank in the UK for its domestic call centre staff, using a bespoke program created to access customer accounts which cannot easily be migrated to Windows. OS/2 has been used by the Stop & Shop supermarket chain (and has been installed in new stores as recently as March 2010). OS/2 has been used on ticket machines for Tramlink in outer-London. OS/2 has been used in Metropolitan Transportation Authority, New York City's subway system for MetroCards. Rather than interfacing with the user, it connects simple computers and the mainframes. When NYC MTA finishes its transition to contactless payment, OS/2 will be removed.
Subway History: How OS/2 Powered The NYC Subway For Decades
'', Andrew Egan (writer), Andrew Egan, Jun 13, 2019, ''Tedium'' OS/2 was used in checkout systems at Safeway Inc, Safeway supermarkets. OS/2 was used by Trenitalia, both for the desktops at Ticket Counters and for the Automatic Ticket Counters up to 2011. Incidentally, the Automatic Ticket Counters with OS/2 were more reliable than the current ones running a flavor of Windows. OS/2 was used as the main operating system for Abbey National General Insurance motor and home direct call centre products using the PMSC Series III insurance platform on DB2.2 from 1996-2001.

Awards

''BYTE'' in 1989 listed OS/2 as among the "Excellence" winners of the BYTE Awards, stating that it "is today where the Macintosh was in 1984: It's a development platform in search of developers". The magazine predicted that "When it's complete and bug-free, when it can really use the Intel 80386, 80386, and when more desktops sport OS/2-capable PCs, OS/2 will—deservedly—supersede DOS. But even as it stands, OS/2 is a milestone product". In March 1995 OS/2 won seven awards * InfoWorld Product of the Year. * Five Awards at CeBIT. ** PC Professional Magazine - Innovation of the Year award. ** CHIP Magazine named OS/2 Warp the Operating System of the Year. ** DOS International named OS/2 Warp the Operating System of the Year. ** 1+1 Magazine awarded it with the Software Marketing Quality award. ** Industrie Forum awarded it with its Design Excellence. * SPA Best Business Software Award.

IBM products utilizing OS/2

IBM has used OS/2 in a wide variety of hardware products, effectively as a form of embedded operating system.

References

External links

os2world.com – Community of OS/2 usersecomstation.ru – Community of eComStation and OS/2 usersnetlabs.org – OpenSource Software for OS/2 and eCShobbes.nmsu.edu – The OS/2 software repositoryEDM/2 – The source for OS/2 developerseCSoft/2 – The OS/2 and eComstation software guide

osFree an open source project to build an OS/2 clone operating systemVoyager Project, a defunct project to reimplement OS/2 on modern technologyOS/2 to Linux API porting projectOpen Source OS/2 API implementation for WindowsMicrosoft documentation of OS/2 API compatibility with Windows NTThe History of OS/2Technical details of OS/2
{{DEFAULTSORT:Os 2 OS/2, 1987 software Discontinued operating systems IBM operating systems Legacy systems X86 operating systems