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OS/2



 
 
OS/2 is a computer operating system
Operating system

An operating system is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer....
, initially created by Microsoft
Microsoft

Microsoft Corporation is a multinational corporation computer technology corporation that develops, manufactures, licenses, and supports a wide range of computer software products for computing devices....
 and IBM
IBM

International Business Machines Corporation, abbreviated IBM and nicknamed "Big Blue" , is a multinational corporation computer technology and consulting corporation headquartered in Armonk, New York, New York, United States....
, 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
IBM Personal System/2

The Personal System/2 or PS/2 was IBM's third generation of personal computers. The PS/2 line, released to the public in 1987, was created by IBM in an attempt to recapture control of the PC market by introducing an advanced Vendor lock-in architecture....
 (PS/2)" line of second-generation personal computer
Personal computer

A personal computer is any general-purpose computer whose original sales price, size, and capabilities make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator....
s. OS/2 is no longer marketed by IBM, and IBM standard support for OS/2 was discontinued on 31 December 2006. Currently, Serenity Systems sells OS/2 under the brand name eComStation
EComStation

eComStation is a PC operating system based on OS/2, published by Serenity Systems, USA. It includes several additions and accompanying software....
.

OS/2 was intended as a protected mode
Protected mode

In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units ....
 successor of PC-DOS
PC-DOS

IBM PC DOS was a DOS operating system for the IBM Personal Computer, sold throughout the 1980s and 2000s....
.






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Quotations


During the next 10 years, millions of programmers and users will utilise this system.

Bill Gates, November 1988, in the Foreword to the Inside OS/2 book by Gordon Letwin, Microsoft's architect for OS/2

I won't pollute it NT with crap!

- Cutler to Bill Gates, upon being told that NT was to have an OS/2 "personality" as an alternative front-end. Technology





Encyclopedia


OS/2 is a computer operating system
Operating system

An operating system is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer....
, initially created by Microsoft
Microsoft

Microsoft Corporation is a multinational corporation computer technology corporation that develops, manufactures, licenses, and supports a wide range of computer software products for computing devices....
 and IBM
IBM

International Business Machines Corporation, abbreviated IBM and nicknamed "Big Blue" , is a multinational corporation computer technology and consulting corporation headquartered in Armonk, New York, New York, United States....
, 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
IBM Personal System/2

The Personal System/2 or PS/2 was IBM's third generation of personal computers. The PS/2 line, released to the public in 1987, was created by IBM in an attempt to recapture control of the PC market by introducing an advanced Vendor lock-in architecture....
 (PS/2)" line of second-generation personal computer
Personal computer

A personal computer is any general-purpose computer whose original sales price, size, and capabilities make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator....
s. OS/2 is no longer marketed by IBM, and IBM standard support for OS/2 was discontinued on 31 December 2006. Currently, Serenity Systems sells OS/2 under the brand name eComStation
EComStation

eComStation is a PC operating system based on OS/2, published by Serenity Systems, USA. It includes several additions and accompanying software....
.

OS/2 was intended as a protected mode
Protected mode

In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units ....
 successor of PC-DOS
PC-DOS

IBM PC DOS was a DOS operating system for the IBM Personal Computer, sold throughout the 1980s and 2000s....
. Notably, basic system call
System call

In computing, a system call is the mechanism used by an application program to request service from the kernel based on the Monolithic_kernel or to system servers on operating systems based on the microkernel-structure....
s were modeled after MS-DOS
MS-DOS

MS-DOS is an operating system commercialized by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the main operating system for personal computers during the 1980s....
 calls; their names even started with "Dos" and it was possible to create "Family Mode" applications: text mode
Text mode

Text mode is a kind of computer display mode in which the content of the screen is internally represented in terms of textual characters rather than individual pixels....
 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
Unix

Unix is a computer operating system originally developed in 1969 by a group of American Telephone & Telegraph employees at Bell Labs, including Ken Thompson , Dennis Ritchie, Douglas McIlroy, and Joe Ossanna....
 and Xenix
Xenix

Xenix is a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. The Santa Cruz Operation later acquired exclusive rights to the software, and eventually began distributing it as SCO UNIX....
.

Development history


Enthusiastic beginnings

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 as a textmode
Text mode

Text mode is a kind of computer display mode in which the content of the screen is internally represented in terms of textual characters rather than individual pixels....
-only OS. However, it featured a rich API
Application programming interface

An application programming interface is a set of subroutine, data structures, class and/or Protocol provided by library and/or operating system Service s in order to support the building of applications....
 for controlling the video display
Display device

A display device is an output device for presentation of information for visual, tactile or Hearing_ reception, acquired, stored, or transmitted in various forms....
 (VIO) and handling keyboard and mouse events so that programmers writing for protected-mode
Protected mode

In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units ....
 no longer had to call the BIOS
BIOS

In computing, the Basic Input/Output System , also known as the System BIOS, is a de facto standard defining a firmware interface for IBM PC Compatible computers....
 or access hardware directly. In addition, development tools included a subset of the video and keyboard APIs as linkable libraries so that family mode programs were able to run under MS-DOS. A task-switcher named Program Selector was available through the Ctrl-Esc hotkey combination, allowing the user to select among multitasked text-mode sessions (or screen groups; each could run multiple programs).

Communications and database-oriented extensions were delivered in 1988, as part of OS/2 1.0 Extended Edition: SNA
Systems Network Architecture

Systems Network Architecture is IBM's proprietary computer network architecture created in 1974. It is a complete protocol stack for interconnecting computers and their resources....
, X.25
X.25

X.25 is an ITU-T standard network layer protocol for Packet switched network wide area network communication. An X.25 WAN consists of Packet switching nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links....
/APPC
Advanced Program-to-Program Communication

In computing, Advanced Program to Program Communication or APPC is a Protocol which computer programs can use to communicate over a computer network....
/LU 6.2, LAN Manager
LAN Manager

The LAN Manager was a Network operating system from Microsoft developed in cooperation with 3Com. It was designed to succeed 3Com's 3+Share network server software which ran on top of MS-DOS....
, Query Manager
Query Management Facility

Query Management Facility is a query tool invented by IBM, for interfacing with their IBM DB2 system. The most recent version is Version 9.2.An example of QMF query might be:...
, SQL.

The promised GUI, Presentation Manager, was introduced with OS/2 1.1 in October, 1988. It had an almost identical user interface to Windows 2.1.

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.

Version 1.2 introduced Installable Filesystems and notably the HPFS filesystem. HPFS provided a number of improvements over the older FAT
File Allocation Table

File Allocation Table or FAT is a computer file system architecture now widely used on most computer systems and most memory cards, such as those used with digital cameras....
 filesystem, including long filenames and a form of alternate data streams
Fork (filesystem)

In computer file systems, a fork is additional data associated with a file system object. A file system might support only one fork per file or might support multiple named forks....
 called Extended Attributes. In addition, extended attributes were also added to the FAT filesystem.

The Extended Edition of 1.2 introduced TCP/IP and Ethernet
Ethernet

Ethernet is a family of Data frame-based computer networking technologies for local area networks . The name comes from the physical concept of the Luminiferous aether....
 support.

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

Breakup

The collaboration between IBM and Microsoft unraveled in 1990, between the releases of Windows 3.0
Windows 3.0

Windows 3.0 is the third major release of Microsoft Microsoft Windows, and was released on 22 May 1990. It became the first widely successful version of Windows and a powerful rival to Macintosh and the Commodore Amiga on the GUI front....
 and OS/2 1.3. Initially, at least publicly, Microsoft continued to insist the future belonged to OS/2. Steve Ballmer
Steve Ballmer

Steven Anthony Ballmer is an United States businessman and has been the chief executive officer of Microsoft since January 2000. Ballmer is the second person after Roberto Goizueta to become a billionaire in U.S....
 of Microsoft even took to calling OS/2 "Windows Plus". However, 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 only available as an expensive 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 a franchise based on Windows. Several technical and practical reasons contributed to this breakup:

  • 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, including systems that could not support the features Microsoft wanted. Microsoft programmers also became frustrated with IBM's bureaucracy and its use of lines of code
    Source lines of code

    Source lines of code is a software metric used to measure the size of a Computer software by counting the number of lines in the text of the program's source code....
     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
    Code bloat

    Code bloat is the production of code that is perceived as unnecessarily long, slow, or otherwise wasteful of resources.Code bloat can also be caused by inadequacies in the language in which the code is written, or inadequacies in the compiler used to compile the language....
    .


  • Differences in API: OS/2 was announced when Windows 2.0
    Windows 2.0

    Windows 2.0 was a 16-bit Microsoft Windows graphical user interface-based operating environment that superseded Windows 1.0. Windows 2.0 was supplemented by Windows 2.1x and Windows 2.1x in 1988....
     was near completion, and the Windows API 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. IBM's involvement was much more successful in redefining Windows' visual appearance after the 1.0 release, giving it what is today perceived as the "Windows 3.0 look".


  • OS/2 targeted the 80286 processor: IBM insisted on supporting the Intel 80286
    Intel 80286

    The Intel 286, introduced on February 1, 1982, was an x86 16-bit microprocessor with 134,000 transistors.It was widely used in IBM PC compatible computers during the mid 1980s to early 1990s....
     processor, with its 16-bit segmented memory mode, due to commitments made to customers who had purchased many 80286-based PS/2's because of IBM's promises surrounding OS/2. Until release 2.0 in April 1992, OS/2 ran in 16-bit protected mode
    Protected mode

    In computing, protected mode, also called protected virtual address mode, is an operational mode of x86-compatible central processing units ....
     and therefore could not benefit from the Intel 80386
    Intel 80386

    The Intel 80386, otherwise known as the i386 or just 386, is a microprocessor which has been used as the central processing unit of many personal computers and workstations since 1986....
    's much simpler 32-bit
    32-bit

    The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or -2,147,483,648 through 2,147,483,647 using two's complement encoding....
     flat memory model
    Flat memory model

    In low level software design, a flat memory model refers to the memory addressing paradigm. A flat memory model uses a linear addressing scheme, allowing direct addressing all of the available memory locations....
     and virtual 8086 mode
    Virtual 8086 mode

    In the 80386 microprocessor and later, Virtual 8086 mode, also called virtual real mode or VM86, allows the execution of real mode applications that are protected mode#Real_mode_application_compatibility directly in protected mode....
     features. This was especially painful in providing support for DOS applications. While, in 1988, Windows/386 2.1
    Windows 2.1x

    Windows 2.1x is a family of Microsoft Windows graphical user interface-based operating environments.Less than a year after the release of Windows 2.0, Windows/286 2.10 and Windows/386 2.10 were released on 27 May 1988....
     could run several preemptively multitasked DOS applications, including expanded memory
    Expanded memory

    In computing, expanded memory is a system of bank switching introduced around 1984 that provided additional memory to MS-DOS programs that required more than what was available in conventional memory....
     (EMS) emulation, OS/2 1.3, released in 1991, was still limited to one 640KB "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
Dave Cutler

David Neil Cutler, Sr. is an United States software engineer, designer and developer of several operating systems including the RSX-11M, OpenVMS and VAXELN systems of Digital Equipment Corporation and Windows NT of Microsoft....
, former VMS
OpenVMS

OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is the name of a high-end computer server operating system that runs on the VAX and DEC Alpha families of computers, developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts , and most recently on Hewlett-Packard systems built around the In...
 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 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 and the diversion of IBM funds earmarked for OS/2 development towards Windows. 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 Windows NT
Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was originally designed to be a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix....
, 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 waiting 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, 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. OS/2 support also includes Presentation Manager support with the addition of the Windows NT Add-On Subsystem for Presentation Manager.

32-bit era

OS/2 2.0 was released in April 1992. It provided a 32-bit API for native programs, though the OS itself was a mixture of 16-bit and 32-bit code. It included a new GUI environment called the Workplace Shell
Workplace Shell

The Workplace Shell is an award-winning object-oriented desktop shell produced by IBM's Boca Raton development lab for OS/2 2.0 using GUI technology licensed from Commodore Amiga....
. This was a fully object-oriented GUI 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 a user could manage programs, files and devices by manipulating objects on the screen.

Although the operating system was 16-bit/32-bit hybrid, performance did not notably degrade on the Pentium Pro, an Intel CPU renowned for poor 16-bit performance at the time. The graphics subsystem (Gre) and multimedia (MMPM/2) were updated in a servicepack (and bundled into OS/2 2.1), Warp 3 brought about a fully 32-bit Windowing system, whilst Warp 4 introduced the object-oriented 32-bit GRADD display driver model.

DOS compatibility
OS/2 2.0 was touted by IBM as "a better DOS than DOS and a better Windows than Windows". 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 actually run a modified copy of Windows 3.0, itself a DOS extender
DOS extender

Developed in the 1980s to cope with the memory limitations of MS-DOS and its derivatives, DOS extenders are programs which enable software to run under the protected mode environment initially introduced with the Intel 80286 processor and later expanded upon with the Intel 80386, even if the host operating system is only capable of operating...
, including Windows 3.0 applications.

Because of the limitations of the Intel 80286
Intel 80286

The Intel 286, introduced on February 1, 1982, was an x86 16-bit microprocessor with 134,000 transistors.It was widely used in IBM PC compatible computers during the mid 1980s to early 1990s....
 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 benefit from the virtual 8086 mode
Virtual 8086 mode

In the 80386 microprocessor and later, Virtual 8086 mode, also called virtual real mode or VM86, allows the execution of real mode applications that are protected mode#Real_mode_application_compatibility directly in protected mode....
 of the Intel 80386
Intel 80386

The Intel 80386, otherwise known as the i386 or just 386, is a microprocessor which has been used as the central processing unit of many personal computers and workstations since 1986....
 processor in order to create a much safer virtual machine
Virtual machine

In computer science, a virtual machine is a software implementation of a machine that executes programs like a real machine.Definitions...
 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 Xenix
Xenix

Xenix is a version of the Unix operating system, licensed by Microsoft from AT&T in the late 1970s. The Santa Cruz Operation later acquired exclusive rights to the software, and eventually began distributing it as SCO UNIX....
) 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 however not run protected-mode DOS programs using the older VCPI 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 also always gave DOS programs the possibility of masking real hardware interrupts, so any DOS program could deadlock (crash) the machine this way. OS/2 could however use a hardware watchdog
Non-Maskable interrupt

A non-maskable interrupt is a computer Central processing unit interrupt that cannot be ignored by standard interrupt masking techniques in the system....
 on selected machines (notably IBM machines) to break out of such a deadlock. Later, release 3.0 leveraged the enhancements of newer Intel 486 and Intel Pentium processors—the Virtual Interrupt Flag—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 machine

Virtual DOS machine is Microsoft's technology that allows running legacy MS-DOS and Windows 3.1x programs on Intel 80386 or higher computers when there is already another operating system running and controlling the hardware....
. 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 ran the user-mode system components of Windows, it was not compatible with Windows device drivers (VxD
VxD

VxD is the device driver model used in Windows 2.1x, the 386 enhanced mode of Windows 3.1x and Windows 9x. They have access to the memory of the kernel and all running processes, as well as raw access to the hardware....
s) and applications needing them.

Multiple Windows applications ran in a single Windows session, just as they would under native Windows. To achieve true isolation between Windows 3.x programs, OS/2 could run multiple copies of Windows in parallel. This approach required considerable system resources, especially memory. It was possible to use DDE
Dynamic Data Exchange

Dynamic Data Exchange is a technology for communication between multiple applications under Microsoft Windows or OS/2....
 between OS/2 and Windows applications, and OLE between Windows applications only.

The "Warp" years

Os2 Warp 3
OS/2 version 3.0, released in 1994, 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
Star Trek

Star Trek is an American Science fiction on television entertainment series and media franchise. The Star Trek fictional universe created by Gene Roddenberry is the setting of six television series including the original 1966 Star Trek: The Original Series, in addition to ten feature films with Star Trek to be released on May 8,...
 terms as internal names for past 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
Patrick Stewart

Patrick Hewes Stewart, Order of the British Empire is an English film, television and Stage actor. He is also Chancellor of the University of Huddersfield....
 was to be the Master of Ceremonies; however Kate Mulgrew
Kate Mulgrew

Kate Mulgrew is an American_people_of_the_United_States actress, most famous for her roles as Mary Ryan on Ryan's Hope and Captain Kathryn Janeway on Star Trek: Voyager....
 of the then-upcoming series Star Trek: Voyager
Star Trek: Voyager

Star Trek: Voyager is a science fiction television series set in the Star Trek universe. The show was created by Rick Berman, Michael Piller, and Jeri Taylor and is the fourth incarnation of Star Trek, which began with the 1960s series Star Trek: The Original Series, created by Gene Roddenberry....
 was substituted at the last minute.

OS/2 Warp offered a host of benefits over OS/2 2.1, notably broader hardware support, greater multimedia capabilities, Internet
Internet

The Internet is a global network of interconnected computers, enabling users to share information along multiple channels. Typically, a computer that connects to the Internet can access information from a vast array of available server and other computers by moving information from them to the computer's local memory....
-compatible networking, and it included a basic office application suite known as IBM Works
IBM Works

IBM Works was an office suite for the IBM OS/2 operating system. It included word processing, spreadsheet, database and personal information manager applications....
. 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
Microsoft Windows

Microsoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces ....
 applications by finding and using Windows already installed on the computer's hard drive. For this reason, the Red Spine version was also known informally and humorously as the "Ferengi
Ferengi

The Ferengi are a fictional Extraterrestrial life in popular culture race from the Star Trek universe. They first appeared in The Last Outpost , the fifth episode of Star Trek: The Next Generation in 1987, during which they made first contact with the United Federation of Planets in 2364 on the planet Delphi Ardu, though they had bee...
" version, a reference to the Star Trek
Star Trek

Star Trek is an American Science fiction on television entertainment series and media franchise. The Star Trek fictional universe created by Gene Roddenberry is the setting of six television series including the original 1966 Star Trek: The Original Series, in addition to ten feature films with Star Trek to be released on May 8,...
 character species, because of this version's "exploitation" of existing MS Windows installations to increase OS/2's usefulness and appeal, much as a Ferengi might do. The nickname was also an homage to its immediate predecessor, "OS/2 for Windows" version 2.1, whose internal IBM codename was indeed "Ferengi". "Blue Spine" included Windows support in its own installation, and so could support Windows applications without a Windows installation. As most computers were sold with Microsoft Windows
Microsoft Windows

Microsoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces ....
 pre-installed, "Red Spine" was the far more popular product. OS/2 Warp Connect, which had full LAN client support built-in, followed in mid-1995. Warp Connect only came with Windows support built in as well and was nicknamed "Grape."

In 1996, Warp 4 added Java
Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java ....
 and speech recognition
Speech recognition

Speech recognition converts spoken words to machine-readable input . The term "voice recognition" is sometimes incorrectly used to refer to speech recognition, when actually referring to speaker recognition, which attempts to identify the person speaking, as opposed to what is being said....
 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
Lotus Notes

Lotus Notes is a client-server, collaborative software application developed and sold by International Business Machines Software Group. IBM defines the software as an "integrated desktop client option for accessing business e-mail, calendars and applications software on [an] IBM Lotus Domino server."....
 was also included, with a number of template databases for contact management, brainstorming, and so forth. The UK-distributed free demo CD-ROM
CD-ROM

CD-ROM is a pre-pressed Compact Disc that contains Computer data storage accessible to, but not writable by, a computer. While the Compact Disc format was originally designed for music storage and playback, the 1985 Yellow Book standard developed by Sony and Philips adapted the format to hold any form of Binary file....
 of OS/2 Warp essentially contained the entire OS and was easily, even accidentally, cracked
Software cracking

Software cracking is the modification of software to remove protection methods: copy protection, trial/demo version, serial number, hardware key, date checks, No-CD crack or software annoyances like nag screens and adware....
, meaning that even people who liked it didn't 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
Australian Personal Computer

APC is a computer magazine in Australia. It is published monthly and comes with a cover-mounted DVD of software. The magazine is published by ACP Magazines Limited, which is one of the companies in the PBL Media group....
 magazine bundled software CD-ROM
CD-ROM

CD-ROM is a pre-pressed Compact Disc that contains Computer data storage accessible to, but not writable by, a computer. While the Compact Disc format was originally designed for music storage and playback, the 1985 Yellow Book standard developed by Sony and Philips adapted the format to hold any form of Binary file....
s, included a full version of Warp 4 that required no activation and was essentially a free release.

IBM also released a version of OS/2 that ran on its PowerPC
PowerPC

PowerPC is a RISC instruction set architecture created by the 1991 Apple Inc.?IBM?Motorola alliance, known as AIM alliance. Originally intended for personal computers, PowerPC CPUs have since become popular embedded system and high-performance processors....
 workstations, and promised to produce low-cost PC style machines with the PowerPC processor. However, the PowerPC version of OS/2 was dropped less than a month after its release, and plans for supporting machines were scuttled. Such moves were seen in the industry as indicative of IBM's lack of long-term commitment to the operating system. Ironically, Microsoft
Microsoft

Microsoft Corporation is a multinational corporation computer technology corporation that develops, manufactures, licenses, and supports a wide range of computer software products for computing devices....
 Windows NT
Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was originally designed to be a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix....
 provided support for PowerPC — a chip co-developed and promoted by IBM — for over 5 years.

Warp 4 was the last widely distributed version of OS/2, and IBM soon announced the end of marketing the operating system to individual users.

Fading out

Overall, OS/2 failed to catch on in the mass market and is today little used outside certain niches where IBM traditionally had a stronghold. For example, many bank installations, especially Automated Teller Machine
Automated teller machine

An automated teller machine is a computerized telecommunications device that provides the customers of a financial institution with access to financial transactions in a public space without the need for a human clerk or bank teller....
s, run OS/2 with a customized user interface; French SNCF
SNCF

SNCF is a France public enterprise. Its functions include operation of rail services for passengers and freight, and maintenance as well as signalling of rail infrastructure owned by R?seau Ferr? de France ....
 national railways used OS/2 1.x in thousands of ticket selling machines. Telecom companies such as Nortel
Nortel

Nortel Networks Corporation , formerly known as Northern Telecom Limited and sometimes known simply as Nortel, is a Multinational corporation telecommunications equipment manufacturing headquartered in Toronto, Ontario, Canada....
 use OS/2 in some voicemail systems. Nevertheless, OS/2 still maintains a small and dedicated community of followers. IBM, unlike Microsoft, charged ISVs
Independent software vendor

Independent software vendor is a business term for companies specializing in making or selling software, designed for mass marketing or for niche markets....
 for the OS/2 development kit (Microsoft gave the Windows SDK
Software development kit

A software development kit is typically a set of development tools that allows a software engineer to create application software for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform....
 away for free).

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 2006-12-31. Sales of OS/2 stopped on 2005-12-23. The latest IBM version is 4.52, which was released for both desktop and server systems in December 2001. A company called Serenity Systems has been reselling OS/2 since 2001, calling it eComStation
EComStation

eComStation is a PC operating system based on OS/2, published by Serenity Systems, USA. It includes several additions and accompanying software....
. The latest stable version is 1.2, released in 2004. Version 2.0 was due for release early in 2007, but release candidate 6a
EComStation

eComStation is a PC operating system based on OS/2, published by Serenity Systems, USA. It includes several additions and accompanying software....
 for version 2.0 was released on 2008-12-06.

IBM is still delivering defect support for a fee. IBM urges customers to migrate their often highly complex applications to e-business
Electronic business

Electronic Business, commonly referred to as "eBusiness" or "e-Business", may be defined as the utilization of information and communication technologies in support of all the activities of business....
 technologies such as Java
Java (programming language)

Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java ....
 in a platform-neutral manner. Once application migration is completed, IBM recommends migration to a different operating system, suggesting Linux
Linux

Linux 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 license...
 as an alternative.

Virtualization
support for running OS/2 under virtualization
Virtualization

In computing, platform virtualization is a virtualization of computers or operating systems. It hides the physical characteristics of computing platform from the users, instead showing another abstract, emulated computing platform....
 appears to be improving in a number of third-party products. 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. During a pre-launch session (ESX3) with VMware in Oslo, Norway, December 2005, they specifically said that OS/2's use of the CPU's ring
Ring (computer security)

In computer science, hierarchical protection domains, often called protection rings, are a mechanism to protect data and functionality from faults and malicious behaviour ....
 2 was the reason that it would not run in VMware. A beta of VMWare Workstation 2.0 released in January 2000 was the first hypervisor
Hypervisor

A hypervisor, also called virtual machine monitor , is a computer hardware platform virtualization software that allows multiple operating systems to run on a host computer concurrently....
 that could run OS/2 at all. Later, the company decided to drop official OS/2 support, presumably because it would require serious work that cannot be economically justified. Although, it is still possible to boot OS/2 by setting guestOS = "os2experimental" in the .vmx file of the VM (checked with VMware Workstation 3.0 and 5.5), but trying to run different versions of OS/2 leads to frustrating problems. Specifically, one can run OS/2 Warp 4 at Fixpack 5, but installing later Fixpacks will make the virtual machine unusable. eComStation 1.2 and 2.0 beta 4 will not install. Versions 1.x will crash immediately with a "TRAP 0000". Versions 2.x are too ancient to recognize the simulated IDE CD-ROM, do not recognize the virtual SCSI hardware and can crash with "TRAP 000C" after some operations. Version 3.0 (Red) and Version 4.0 (Warp 4) seem to work fine under VMWare Server 1.04, however the 'guestOS = "os2experimental"' setting will cause an error. Changing the vmx file setting to guestOS = "other" seems to work just as well for both of these versions. Microsoft
Microsoft

Microsoft Corporation is a multinational corporation computer technology corporation that develops, manufactures, licenses, and supports a wide range of computer software products for computing devices....
 continues to support OS/2 as a hosted operating system
Operating system

An operating system is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer....
 in its Virtual PC
Virtual PC

Virtual PC can refer to:* A Virtual machine, the generic name for this kind of technology* Microsoft Virtual PC, a product from Microsoft...
 product. OS/2 and eComStation can both be installed in Microsoft VirtualPC (checked with VPC 2004) although a virtual machine built in VPC 2004 would not run in VPC 2007. These operating systems can be installed under VPC 2007, with and without hardware-assisted virtualization. OS/2, eCS and other operating systems should work fine with the hardware-assisted virtualization checkbox grayed out (claiming that it's enabled when it actually isn't) with Pentium III class emulation and MMX, SSE2 and Intel VT processor features.

VirtualBox
VirtualBox

VirtualBox is an x86 virtualization software package, originally created by Germany software company innotek, now developed by Sun Microsystems as part of its Sun xVM virtualization platform....
 from Sun Microsystems
Sun Microsystems

Sun Microsystems, Inc. is a multinational corporation vendor of computers, computer components, computer software, and information technology services, founded on February 24, 1982....
 currently supports OS/2 Warp 3, 4 and 4.5 as well as eComStation as guests. Innotek (now part of Sun) also developed the “additions” code in both Virtual PC
Virtual PC

Virtual PC can refer to:* A Virtual machine, the generic name for this kind of technology* Microsoft Virtual PC, a product from Microsoft...
 and Virtual Server
Virtual server

Virtual server may refer to:* Virtual private server, a method of server hosting using virtual machines.* Virtual hosting, a method that servers such as webservers use to host more than one domain name on the same computer....
 which greatly improves host-guest OS interactions in OS/2. However, attempting to run OS/2 and eComStation can still be difficult, if not impossible to run, because of the strict requirements of VT-x/AMD-V hardware-enabled virtualization and only MCP2 is reported to work in a reliable matter.

QEMU
QEMU

QEMU is a central processing unit emulator that relies on dynamic binary translation to achieve a reasonable speed while being easy to port on new host CPU architectures....
 and Bochs
Bochs

Bochs is a portable x86 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under GNU Lesser General Public License....
 also support running OS/2 as they're full x86 system emulators and not virtualization software, and thus emulates the entire x86 architecture instead of relying on the host CPU, essentially allowing OS/2 unrestricted access to Ring 2, albeit an emulated one.

The difficulties in efficiently running OS/2 have, at least once, created an opportunity for a new virtualization
Virtualization

In computing, platform virtualization is a virtualization of computers or operating systems. It hides the physical characteristics of computing platform from the users, instead showing another abstract, emulated computing platform....
 company. A large German bank 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
Hypervisor

A hypervisor, also called virtual machine monitor , is a computer hardware platform virtualization software that allows multiple operating systems to run on a host computer concurrently....
. Once it was determined that VMware was not a possibility, it hired a group of Russian software developer
Software developer

A software developer is a person or organization concerned with facets of the software development process wider than design and coding, a somewhat broader scope of computer programming or a specialty of project manager including some aspects of Software product management....
s to write a host-based hypervisor that would officially support OS/2. Thus, the Parallels, Inc.
Parallels, Inc.

Parallels, Inc. is a privately-held virtualization technology company with offices all around the world . Parallels US offices are in Seattle, WA and Washington, D.C.....
 company and their Parallels Workstation
Parallels Workstation

Parallels Workstation is the first commercial software product released by Parallels, Inc., a developer of desktop and server virtualization software....
 was born.

ATMs
ATM
Automated teller machine

An automated teller machine is a computerized telecommunications device that provides the customers of a financial institution with access to financial transactions in a public space without the need for a human clerk or bank teller....
 vendors NCR Corporation
NCR Corporation

NCR Corporation is a technology company specializing in products for the retail and financial sectors. Its main products are point of sale, automatic teller machines, cheque processing systems, barcode reader, and business consumables....
 and Diebold Incorporated
Diebold

Diebold, Inc. is a United States-based security systems corporation that is engaged primarily in the sale, manufacture, installation and service of self-service transaction systems , electronic and physical security products , voting machines, and software and integrated systems for global financial and commercial markets....
 have both adopted Microsoft Windows XP as their migration path from OS/2.

Diebold Incorporated
Diebold

Diebold, Inc. is a United States-based security systems corporation that is engaged primarily in the sale, manufacture, installation and service of self-service transaction systems , electronic and physical security products , voting machines, and software and integrated systems for global financial and commercial markets....
 initially shipped XP Embedded Edition exclusively, but following extensive pressure from customer banks to support a common OS, switched to XP Professional to match their primary competitor NCR Corporation
NCR Corporation

NCR Corporation is a technology company specializing in products for the retail and financial sectors. Its main products are point of sale, automatic teller machines, cheque processing systems, barcode reader, and business consumables....
.

Security niche

OS/2 has very few native computer virus
Computer virus

A computer virus is a computer program that can copy itself and infect a computer without the permission or knowledge of the user. The term "virus" is also commonly but erroneously used to refer to other types of malware, adware and spyware programs that do not have the reproductive ability....
es. Its design possibly could have made it vulnerable, but its reduced market share appears to have 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.

Future

There is a community of OS/2 users and developers, along with loyal company customers, hoping that IBM will release OS/2 or a significant part of it as open source
Open source

Open source is an approach to design, development, and distribution offering practical accessibility to a product's source . Some consider open source as one of various possible design approaches, while others consider it a critical Strategy element of their business operations....
. Petitions to that end were made in 2005 and 2007, but IBM declined, citing legal, technical and strategic reasons. It is unlikely that the entire OS will be open at some point in the future, because it contains third-party code, much of it from Microsoft
Microsoft

Microsoft Corporation is a multinational corporation computer technology corporation that develops, manufactures, licenses, and supports a wide range of computer software products for computing devices....
.

Also IBM made a deal with Commodore
Commodore International

Commodore, the commonly used name for Commodore International, was a United States electronics company based in West Chester, Pennsylvania which was a vital player in the home computer/personal computer field in the 1980s....
 to license Amiga
Amiga

The Amiga is a family of personal computers originally developed by Amiga Corporation. Development on the Amiga began in 1982 with Jay Miner as the principal hardware designer....
 technology for OS/2 2.0 and above in exchange for the REXX
REXX

REXX is an Interpreted language programming language which was developed at IBM. It is a structured high-level programming language which was designed to be both easy to learn and easy to read....
 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.

Version 2.0 had such a long design cycle that its design started while OS/2 1.1 was still under development, and thus, portions of it were developed in conjunction with Microsoft, even though Microsoft never released a branded version of 2.0 (although they did release a beta in their name). IBM's contribution to versions 1.2 and earlier mostly resides in the GUI components; however, bug fixes and substantial performance changes to the entire system in 1.3 were made by IBM , and much more of the overall system (including the kernel) for 2.0 was developed by IBM.

The aborted PowerPC
PowerPC

PowerPC is a RISC instruction set architecture created by the 1991 Apple Inc.?IBM?Motorola alliance, known as AIM alliance. Originally intended for personal computers, PowerPC CPUs have since become popular embedded system and high-performance processors....
 port did not involve Microsoft at all, and has been proposed as the basis for an open-source 64-bit version of OS/2.

Still, the community has suggested that, even if only the IBM
IBM

International Business Machines Corporation, abbreviated IBM and nicknamed "Big Blue" , is a multinational corporation computer technology and consulting corporation headquartered in Armonk, New York, New York, United States....
 portion of it is made open, the missing parts could be written by the same community to form a next-generation version of the OS. Code could perhaps be integrated from the Wine
Wine (software)

Wine is a free software software application that aims to allow Unix-like computer operating systems on the x86 architecture or x86-64 architecture to execute programs written for Microsoft Windows....
 or ReactOS
ReactOS

ReactOS is a computer operating system intended to be Application binary interface with application software and device drivers made for Microsoft Windows NT versions 5.x and up ....
 projects. Many developers believe that these missing parts include many of the legacy 16-bit components not revised since OS/2 1.x, and are exactly the parts that should be rewritten anyway. There is an ongoing petition to open parts of the OS arranged by OS2World.com.

With the possibility of an open-source future for OS/2, the OS may be given a new lease of life. IBM's current and heavy involvement with several open source projects indicate that opening parts of OS/2 will not be difficult for the company. But until then, OS/2's future remains in limbo.

Open source operating systems such as Linux
Linux

Linux 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 license...
 have already profited from OS/2 indirectly through IBM's release of the improved JFS file system
File system

In computing, a file system is a method for store and organize computer files and the data they contain to make it easy to find and access them....
 which was ported from the OS/2 code base.

OS/2 programs will eventually use emulator
Emulator

An emulator duplicates the functions of one system using a different system, so that the second system behaves like the first system. This focus on exact reproduction of external behavior is in contrast to some other forms of computer simulation, which can concern an abstract model of the system being simulated....
s and compatibility layer
Compatibility layer

A compatibility layer is a term that refers to components that allow for non-native support of components.In software engineering, a compatibility layer allows binaries for a foreign system to run on a host system....
s for running programs dedicated for OS/2.

Technology

The graphic system has a layer named Presentation Manager
Presentation Manager

Presentation Manager is the graphical user interface that International Business Machines and Microsoft introduced in version 1.1 of their operating system OS/2 in 1988....
 that manages windows, fonts, and icons. This is similar in functionality to a non-networked version of X11 or the Windows GDI. On top of this lies the Workplace Shell
Workplace Shell

The Workplace Shell is an award-winning object-oriented desktop shell produced by IBM's Boca Raton development lab for OS/2 2.0 using GUI technology licensed from Commodore Amiga....
 (WPS) introduced in OS/2 2.0. WPS is an object-oriented 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 3rd 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
Common User Access

Common User Access is a standard for user interfaces to operating systems and computer programs. It was developed by IBM and first published in 1987 as part of their Systems Application Architecture....
 user interface standards.

Hardware vendors were reluctant to support device drivers for alternative operating systems including OS/2 and Linux, leaving users with few choices from a select few vendors. To relieve this issue for video cards, IBM licensed a reduced version of the Scitech display drivers
UniVBE

UniVBE is a software driver that allows DOSs written to the VESA BIOS standard to run on almost any display device made in the last 15 years or so....
, allowing users to choose from a wide selection of cards supported through Scitech's modular driver design.

WPS represents objects such as disks, folders, files, program objects, and printers using the System Object Model
System Object Model

In computing, the System Object Model is an object-oriented shared library system developed by IBM. A distributed version based on CORBA, DSOM, allowed objects on different computers to communicate....
 (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
Çorba

Chorba , shurpa , sorpa , or shorpo is one of various kinds of soup or stew found in national cuisines across Eurasia. The term is likely of Persian language or Turkic languages origin....
. SOM is similar to, and a direct competitor to, Microsoft's Component Object Model
Component Object Model

Component Object Model is an interface standard for software componentry introduced by Microsoft in 1993. It is used to enable interprocess communication and dynamic object creation in a large range of programming languages....
. SOM and DSOM are no longer being developed.

OS/2 also includes a radical advancement in application development with compound document technology called OpenDoc
OpenDoc

OpenDoc was a multi-platform software componentry framework standard for compound documents, inspired by the Xerox Star system and intended as an alternative to Microsoft's Object Linking and Embedding ....
, which was developed with Apple. OpenDoc proved interesting as a technology, but was not widely used or accepted by users or developers. OpenDoc is also no longer being developed.

The multimedia capabilities of OS/2 are accessible through Media Control Interface
Media Control Interface

The Media Control Interface, MCI in short, is an aging high-level API developed by Microsoft and IBM for controlling multimedia peripherals connected to a Microsoft Windows or OS/2 computer, such as CD-ROM players and audio controllers....
 commands. The last update (bundled with the IBM version of Netscape Navigator
Netscape Navigator

Netscape Navigator and Netscape are the names for the proprietary software web browser popular in the 1990s, and the flagship product of the Netscape Communications Corporation, and the dominant web browser in terms of Usage share of web browsers....
 plugins) added support for MPEG files. Support for newer formats like PNG, progressive JPEG
JPEG

In computing, JPEG is a commonly used method of for photographic images. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality....
, DivX
DivX

DivX is a brand name of products created by DivX, Inc. , including the DivX Codec which has become popular due to its ability to video compression lengthy video segments into small sizes while maintaining relatively high visual quality....
, Ogg
Ogg

Ogg is a free file format, open standard container format maintained by the Xiph.Org Foundation. The Ogg format is unrestricted by software patents and is designed to provide for efficient streaming media and manipulation of high quality digital multimedia....
, MP3
MP3

MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a digital audio Encoder format using a form of lossy data compression. It is a common audio format for consumer audio storage, as well as a de facto standard encoding for the transfer and playback of music on digital audio players....
 comes from third parties. Sometimes it is integrated with the multimedia system, but in other offers it comes as standalone applications.

The TCP/IP stack is based on the open source
Open source

Open source is an approach to design, development, and distribution offering practical accessibility to a product's source . Some consider open source as one of various possible design approaches, while others consider it a critical Strategy element of their business operations....
 BSD stack.

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 command line: OS/2 divided programs into strict categories and communication between programs of different categories was problematic: It was not possible to enter fullscreen mode from a "windowed OS/2 session"; a separate "fullscreen OS/2 session" was required, which could not be made windowed. OS/2 sessions could launch new DOS sessions, but with DOS sessions (which could be toggled fullscreen) it was not possible, in theory, to start OS/2 programs. Therefore transparent piping of data was not possible. There were however undocumented calls that allowed the development of some user tools to overcome these limitations. Worse, in the absence of 8.3 aliases for filenames and directories and DOS API extensions supporting long filenames, it was also problematic to give DOS programs access to files managed from OS/2 programs. Even native OS/2 programs had problems communicating: a command-line program could not fully access the system clipboard, which was reserved for "GUI" programs. Workarounds consisted in creating special helper programs (for example an invisible GUI program just for accessing the clipboard) or in using client-server setups, where the client and the server were different types of programs, but communicated using some available way. Just as OS/2 1.x, the 32-bit system was apparently designed with the idea that users would rapidly make a switch to all-native programs.
  • No unified object handles. 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 alternatively, 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.
  • No unified virtual memory and disk cache. Modern operating systems can use the entire available RAM for disk caching and can map files into the address space of processes. OS/2 had a dedicated memory pool for disk caching and could not map files. This could result in decreased performance and RAM waste.


Quotations


During the next 10 years, millions of programmers and users will utilize this system. Bill Gates
Bill Gates

William Henry "Bill" Gates III is an United States business magnate, philanthropist, author, the List of the 100 wealthiest people , and chairman of the board of Microsoft, the software company he founded with Paul Allen....
, November 1988 (in the Foreword to the Inside OS/2 book by Gordon Letwin
Gordon Letwin

Gordon Letwin is an United States software developer who is known for being one of the original eleven Microsoft employees.Prior to joining Microsoft, he worked for Heathkit, on HDOS and Benton Harbor Basic....
, Microsoft's architect for OS/2).

This quotation could be compared with another one, by Dave Cutler
Dave Cutler

David Neil Cutler, Sr. is an United States software engineer, designer and developer of several operating systems including the RSX-11M, OpenVMS and VAXELN systems of Digital Equipment Corporation and Windows NT of Microsoft....
 and coming from his introduction to the Inside Windows NT book:
"In the summer of 1988, I received an interesting call from Bill Gates at Microsoft. He asked whether I'd like to come over and talk about building a new operating system at Microsoft for personal computers. [...] What Bill had to offer was the opportunity to build another operating system, one that was portable [...]."


However, as "Inside Windows NT" says in chapter one, section 1.1, "An Operating System for the 1990s":
"Originally, the plan also called for NT to have an OS/2-style user interface and to provide the OS/2 application programming interface (API) as its primary programming interface. Midway through the development of the system, however, Microsoft Windows 3.0 hit the market and was an instant success, in contrast to OS/2, which had not caught on with large numbers of users."


Historical uses

OS/2 was widely used in Brazil
Brazil

Brazil , officially the Federative Republic of Brazil , is a country in South America. It is the List of countries and outlying territories by total area country by geographical area, occupying nearly half of South America, the List of countries by population country, and the fourth most populous democracy in the world....
ian banks. Banco do Brasil
Banco do Brasil

Banco do Brasil S.A. Banco do Brasil is controlled by the Brazilian government but its stock is traded at the Bovespa and its management follows standard international banking practices ....
 had a peak 10,000 machines running OS/2 Warp in the 1990s. OS/2 was used in automated teller machine
Automated teller machine

An automated teller machine is a computerized telecommunications device that provides the customers of a financial institution with access to financial transactions in a public space without the need for a human clerk or bank teller....
s until 2006. The workstations and automated teller machine
Automated teller machine

An automated teller machine is a computerized telecommunications device that provides the customers of a financial institution with access to financial transactions in a public space without the need for a human clerk or bank teller....
s have been migrated to Linux
Linux

Linux 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 license...
.

OS/2 also 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 was used by radio personality Howard Stern
Howard Stern

Howard Allan Stern is an American radio presenter and media personality, best known for hosting The Howard Stern Show, currently an uncensored talk radio show that airs on Howard 100 on SIRIUS XM Radio....
. He once had a 10 minute on-air rant about OS/2 versus Windows 95
Windows 95

Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Microsoft Windows products....
 and recommended OS/2. He also used OS/2 on his IBM 760CD laptop.

See also

  • History of the graphical user interface
    History of the graphical user interface

    The graphical user interface, understood as the use of graphic icons and a pointing device to control a computer, has over the last four decades a steady history of incremental refinements built on some constant core principles....


Further reading

— Necasek discusses an aborted port to PowerPC
PowerPC

PowerPC is a RISC instruction set architecture created by the 1991 Apple Inc.?IBM?Motorola alliance, known as AIM alliance. Originally intended for personal computers, PowerPC CPUs have since become popular embedded system and high-performance processors....
 machines.

External links

  • The OS/2 software repository