Editing OS/2 (section)

====OS/2 1.3 (1990){{anchor|1.3}}====
[[File:MSOS2.png|thumb|Logo of Microsoft's OS/2 until the breakup]]
The collaboration between IBM and Microsoft unravelled in 1990, between the releases of [[Windows 3.0]] and OS/2 1.3. During this time, Windows 3.0 became a tremendous success, selling millions of copies in its first year.<ref>{{cite web|url=https://www.thoughtco.com/unusual-history-of-microsoft-windows-1992140|title=The Unusual History of Microsoft Windows|last=Bellis|first=Mary|work=ThoughtCo.|publisher=Dotdash}}</ref> Much of its success was because Windows 3.0 (along with MS-DOS) was bundled with most new computers.<ref>{{cite web | title=Windows History (1985–1994) | author=Thomas Hormby | work=osviews.com | date=25 May 2005 | url=http://www.osopinion.com/modules.php?op=modload&name=News&file=article&sid=4484 | url-status=dead | archive-url=https://web.archive.org/web/20060312130710/http://www.osopinion.com/modules.php?op=modload&name=News&file=article&sid=4484 | archive-date=March 12, 2006 | access-date=April 9, 2013 }}</ref> OS/2, on the other hand, was available only as an additional stand-alone software package. In addition, OS/2 lacked [[device driver]]s for many common devices such as printers, particularly non-IBM hardware.<ref>{{cite web|title=OS/2 1.1 and 1.2: The Early Years|author=Michal Necasek|work=The History of OS/2|date=2001-10-29|url=http://pages.prodigy.net/michaln/history/os211/index.html|url-status=dead|archive-url=https://web.archive.org/web/20060613211334/http://pages.prodigy.net/michaln/history/os211/index.html|archive-date=2006-06-13}}</ref> 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.<ref>{{cite web|title=Windows Server 2003: The Road To Gold|author=Paul Thurrott|work=winsupersite.com|date=24 January 2003|url=http://www.winsupersite.com/reviews/winserver2k3_gold1.asp|url-status=dead|archive-url=https://web.archive.org/web/20100604082534/http://www.winsupersite.com/reviews/winserver2k3_gold1.asp|archive-date=4 June 2010}}</ref>

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 [[Computer font|fonts]], that IBM's hardware did not support. Microsoft programmers also became frustrated with IBM's bureaucracy and its use of [[Source lines of code|lines of code]] to measure [[programmer productivity]].<ref>{{cite book|last1=Gates|first1=Bill|author-link=Bill Gates|first2=Nathan|last2=Myhrvold|author-link2=Nathan Myhrvold|first3=Peter|last3=Rinearson|author-link3=Peter Rinearson|title=The Road Ahead|isbn=0-670-77289-5|url=https://archive.org/details/roadahead00gate|date=1996-10-08}}</ref> IBM developers complained about the terseness and lack of [[comment (computer programming)|comments]] in Microsoft's code, while Microsoft developers complained that IBM's code was [[code bloat|bloated]].<ref>{{cite book|author=Michael Lee Vasu|author2=Debra W. Stewart|author3=G. David Garson|title=Organizational behavior and public management|page=268|isbn=978-0-8247-0135-2|url=https://books.google.com/books?id=bu2JkldQjXcC&q=IBM+measure+lines+of+code&pg=PA267|date=1998-03-03|publisher=Taylor & Francis }}</ref>

The two products have significant differences in API. OS/2 was announced when [[Windows 2.0]] was near completion, and the [[Windows API]] already defined. However, IBM requested that this API be significantly changed for OS/2.<ref>{{cite web|title="What's happening to OS/2," a Usenet post by Gordon Letwin from August 1995, the point of view of a Microsoft employee|author=Gordon Letwin|work=Google Groups|url=http://groups.google.com/group/comp.os.ms-windows.misc/msg/d710490b745d5e5e|access-date=2007-10-18|archive-url=https://web.archive.org/web/20070923013722/http://groups.google.com/group/comp.os.ms-windows.misc/msg/d710490b745d5e5e|archive-date=2007-09-23|url-status=dead}}</ref> 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.

[[File:OS2-1.3-desktop.png|thumb|right|OS/2 1.3 was the final 16-bit only version of OS/2, and the last to be sold by Microsoft.]]

OS/2 1.x targets the [[Intel 80286]] processor and DOS fundamentally does not. IBM insisted on supporting the 80286 processor, with its 16-bit [[x86 memory segmentation|segmented memory]] 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.<ref name="BillGatesInterviewSmithsonian">{{cite interview |last=Gates |first=Bill |subject-link= Bill Gates |interviewer= David Allison |url= http://americanhistory.si.edu/comphist/gates.htm |title= Bill Gates Interview |type= transcript of a Video History interview |work= Computer History Collection |publisher= National Museum of American History, Smithsonian Institution |access-date= April 10, 2013 }}</ref> Until release 2.0 in April 1992, OS/2 ran in 16-bit [[protected mode]] and therefore could not benefit from the [[Intel 80386]]'s much simpler [[32-bit computing|32-bit]] [[flat memory model]] and [[virtual 8086 mode]] features. This was especially painful in providing support for DOS applications. While, in 1988, [[Windows 2.1x|Windows/386 2.1]] could run several [[cooperative multitasking|cooperatively multitasked]] DOS applications, including [[expanded memory]] (EMS) emulation, OS/2 1.3, released in 1991, was still limited to one {{nowrap|640 kB}} "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]], former [[OpenVMS|VAX/VMS]] 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 [[DEC MICA|MICA]] project at [[Digital Equipment Corporation|Digital]] rather than creating a "DOS plus". His [[Windows NT|NT OS/2]] was a completely new architecture.<ref>{{cite book|author=Microsoft|title=Inside Out, Microsoft—In Our Own Words|year=2000|publisher=Warner Business Books|isbn=0-446-52739-4}}</ref>

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 Windows NT, 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]], 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.{{Citation needed|date=April 2010}}
One example of NT OS/2 1.x support is in the WIN2K resource kit. Windows NT could also support OS/2 1.x [[Presentation Manager]] and AVIO applications with the addition of the Windows NT Add-On Subsystem for Presentation Manager.<ref name="CompatibilityofOS2basedAppsandAPIs">{{cite web | title=Compatibility of OS/2-based Applications and APIs | author=Microsoft | work=Microsoft TechNet | date=11 September 2008 | url=https://technet.microsoft.com/library/Cc939070 | publisher=Microsoft | access-date=April 9, 2013 }}</ref>