NTFS a journaled secure file system was created for NT. Windows NT also allows for other installable file systems and with versions 3.1 and 3.51 NT could also be installed on DOS's FAT or OS/2's HPFS file systems. Later versions could be installed on a FAT32 partition in select cases including Vista versions.10 Windows Vista and Windows 7 require a FAT32 partition to boot on an EFI based system.11 Development

Microsoft decided to create a portable operating system compatible with OS/2 and POSIX and supporting multiprocessing in October 1988.12 When development started in November 1989 Windows NT was to be known as OS/2 3.013 the third version of the operating system developed jointly by Microsoft and IBM. To ensure portability initial development was targeted at the Intel i860XR RISC processor switching to the MIPS R3000 in late 1989 and then the Intel i386 in 1990.3 Microsoft also continued parallel development of the DOS-based and less resource-demanding Windows environment resulting in the release of Windows 3.0 in May 1990. Windows 3 was eventually so successful that Microsoft decided to change the primary application programming interface for the still unreleased NT OS/2 (as it was then known) from an extended OS/2 API to an extended Windows API. This decision caused tension between Microsoft and IBM and the collaboration ultimately fell apart. IBM continued OS/2 development alone while Microsoft continued work on the newly renamed Windows NT. Though neither operating system would immediately be as popular as Microsoft's MS-DOS or Windows products Windows NT would eventually be far more successful than OS/2.

Microsoft hired a group of developers from Digital Equipment Corporation led by Dave Cutler to build Windows NT and many elements of the design reflect earlier DEC experience with Cutler's VMS and RSX-11. The operating system was designed to run on multiple instruction set architectures and multiple hardware platforms within each architecture. The platform dependencies are largely hidden from the rest of the system by a kernel mode module called the HAL (Hardware Abstraction Layer). Windows NT's kernel mode code further distinguishes between the "kernel" whose primary purpose is to implement processor and architecture dependent functions and the "executive". This was designed as a modified microkernel as the Windows NT kernel does not meet all of the criteria of a pure microkernel. Both the kernel and the executive are linked together into the single loaded module ntoskrnl.exe; from outside this module there is little distinction between the kernel and the executive. Routines from each are directly accessible as for example from kernel-mode device drivers. API sets in the Windows NT family are implemented as subsystems atop the publicly undocumented "native" API; this allowed the late adoption of the Windows API (into the Win32 subsystem). Windows NT was one of the earliest operating systems to use Unicode internally. Driver models Windows NT introduced its own driver model the Windows NT driver model and is incompatible with older driver frameworks. With Windows 2000 the Windows NT driver model was enhanced to become the Windows Driver Model which was first introduced with Windows 98 but was based on the NT driver model.14 Windows Vista added native support for the Windows Driver Foundation which is also available for Windows XP Windows Server 2003 and to an extent Windows 2000. Releases Windows NT releases Version Marketing name Editions Release date RTM build NT 3.1 Windows NT 3.1 Workstation (named just Windows NT) Advanced Server 27 July 1993 528 NT 3.5 Windows NT 3.5 Workstation Server 21 September 1994 807 NT 3.51 Windows NT 3.51 Workstation Server 30 May 1995 1057 NT 4.0 Windows NT 4.0 Workstation Server Server Enterprise Edition Terminal Server Embedded 29 July 1996 1381 NT 5.0 Windows 2000 Professional Server Advanced Server Datacenter Server Advanced/Datacenter Server Limited Edition 17 February 2000 2195 NT 5.1 Windows XP Home Professional 64-bit Edition (Itanium) Media Center (original 2003 2004 & 2005) Tablet PC (original and 2005) Starter Embedded Home N Professional N 25 October 2001 2600 NT 5.1 Windows Fundamentals for Legacy PCs N/A 8 July 2006 2600 NT 5.2 Windows XP 64-bit Edition Version 2003 (Itanium)15 28 March 2003 3790 NT 5.2 Windows Server 2003 Standard Enterprise Datacenter Web Storage Small Business Server Compute Cluster 24 April 2003 3790 NT 5.2 Windows XP Professional x64 Edition 25 April 2005 3790 NT 5.2 Windows Home Server N/A 16 July 2007 3790 NT 6.0 Windows Vista Starter Home Basic Home Premium Business Enterprise Ultimate Home Basic N Business N Business: 30 November 2006 Consumer: 30 January 2007 6000 6001(SP1) 6002(SP2) NT 6.0 Windows Server 2008 Foundation Standard Enterprise Datacenter Web Server HPC Server Itanium-Based Systems16 27 February 2008 6001 6002(SP2) NT 6.117 Windows 7 Starter Home Basic Home Premium Professional Enterprise Ultimate18 22 October 200919 7600 7601(SP1) NT 6.117 Windows Server 2008 R2 Foundation Standard Enterprise Datacenter Web Server HPC Server Itanium-Based Systems 22 October 200920 7600 7601(SP1) NT 6.2 Windows 8 N/A TBC NT 6.2 Windows Server Next N/A TBC Windows NT 3.1 to 3.51 incorporated the Program Manager and File Manager from the Windows 3.x series. Windows NT 4.0 onwards replaced those programs with Windows Explorer (including a taskbar and Start menu) which originally appeared in Windows 95. The first release was given version number 3.1 to match the contemporary 16-bit Windows; magazines of that era claimed the number was also used to make that version seem more reliable than a '.0' release. There were also some issues related to Novell IPX protocol licensing which was apparently limited to 3.1 versions of Windows software.citation needed The NT version number is not now generally used for marketing purposes but is still used internally and said to reflect the degree of changes to the core of the operating system.21 The build number is an internal identifier used by Microsoft's developers and beta testers. Supported platforms NT was written in C and C++22 and is reasonably portable although (as of 2009update) only three architectures are currently supported. That said it proved far more difficult to port applications such as Microsoft Office which were sensitive to issues such as data structure alignment on RISC processors. Unlike Windows CE which routinely runs on a variety of processors the lack of success of RISC-based systems in the desktop market has resulted in nearly all NT deployments being on x86 architecture processors. 32-bit platforms In order to prevent Intel x86-specific code from slipping into the operating system by developers used to developing on x86 chips Windows NT 3.1 was initially developed using non-x86 development systems and then ported to the x86 architecture. This work was initially based on the Intel i860-based Dazzle system and later the MIPS R4000-based Jazz platform. Both systems were designed internally at Microsoft.23 Windows NT 3.1 was released for Intel x86 PC compatible DEC Alpha and ARC-compliant MIPS platforms. Windows NT 3.51 added support for the PowerPC processor in 1995 specifically PReP-compliant systems such as the IBM Power Series desktops/laptops and Motorola PowerStack series; but despite meetings between Michael Spindler and Bill Gates not on the Power Macintosh as the PReP compliant Power Macintosh project failed to ship. Intergraph Corporation ported Windows NT to its Clipper architecture and later announced intention to port Windows NT 3.51 to Sun Microsystems' SPARC architecture24 but neither version was sold to the public as a retail product. Only two of the Windows NT 4.0 variants (IA-32 and Alpha) have a full set of service packs available. All of the other ports done by third parties (Motorola Intergraph etc.) have few if any publicly available updates. Windows NT 4.0 was the last major release to support Alpha MIPS or PowerPC though development of Windows 2000 for Alpha continued until August 1999 when Compaq stopped support for Windows NT on that architecture; and then three days later Microsoft also canceled their AlphaNT program even though the Alpha NT 5 (Windows 2000) release had reached RC2 (build 2128). Microsoft announced on 5 January 2011 that the next major version of the Windows NT family will include support for the ARM architecture. Microsoft demonstrated a preliminary version of Windows (version 6.2.7867) running on an ARM-based computer at the 2011 Consumer Electronics Show.25 According to Microsoft it is a common misconception that the Xbox and Xbox 360 use a modified Windows 2000 kernel.26 They claim that the Xbox operating system was built from scratch but implements a subset of Windows APIs. The idea that it does indeed run a modified copy of the Windows kernel still persists in the community. 64-bit platforms Released versions of NT for Alpha were 32-bit only. The 64 bit port of Windows was originally intended to run on Itanium as well as on Alpha and Alpha hardware was accordingly used internally at Microsoft during early development of 64-bit Windows.2728 This continued for some time after Microsoft publicly announced that it was cancelling plans to ship 64-bit Windows for Alpha because Itanium hardware was not yet available for development.29 Limited Editions of Windows 2000 Advanced Server and Datacenter Server Windows XP 64-Bit and Windows Server 2003 Enterprise and Datacenter support Intel's IA-64 processors. As of June 2010update Microsoft have released seventeen editions for the x64 processor architecture:citation needed Windows XP Professional x64 Edition Windows Server 2003 Standard x64 Edition Windows Server 2003 Enterprise x64 Edition Windows Server 2003 Datacenter x64 Edition Windows Vista Home Basic x64 Edition Windows Vista Home Premium x64 Edition Windows Vista Enterprise x64 Edition Windows Vista Ultimate x64 Edition Windows Server 2008 Web Server x64 Edition Windows Server 2008 Standard x64 Edition Windows Server 2008 Enterprise x64 Edition Windows Server 2008 Datacenter x64 Edition Windows 7 Home Basic x64 Edition Windows 7 Home Premium x64 Edition Windows 7 Professional x64 Edition Windows 7 Enterprise x64 Edition Windows 7 Ultimate x64 Edition. Hardware requirements The minimum hardware specification required to run each release of the professional workstation version of Windows NT has been fairly slow-moving until the 6.0 Vista release which requires a minimum of 15 GB of free disk space a 10-fold increase in free disk space alone over the previous version. Windows NT desktop (x86) minimum hardware requirements NT version CPU RAM Free disk space NT 3.1 NT 3.1 Advanced Server 386 25 MHz 12 MB 16 MB 90 MB NT 3.5 Workstation NT 3.5 Server 386 25 MHz 12 MB 16 MB 90 MB30 NT 3.51 Workstation NT 3.51 Server 386 25 MHz 12 MB 16 MB 90 MB30 NT 4.0 Workstation NT 4.0 Server 486 25 MHz 12 MB 16 MB 124 MB31 2000 Professional 2000 Server Pentium 133 MHz 32 MB 128 MB 650 MB32 XP Pentium 233 MHz 64 MB* 1.5 GB33 Server 2003 Pentium 133 MHz 128 MB 1.5 GB32 Vista Pentium III 800 MHz 512 MB** 15 GB34 7 Pentium III 1 GHz 512 MB** 16 GB35 8*** Pentium III 1 GHz - 12 GB *Windows XP can be run at 64 MB RAM. Some features require 128 MB RAM.36 **Windows Vista and 7 can be run from 512 MB but Microsoft recommends 1 GB.37 ***Information not confirmed (Windows 8) Designation It is popularly believedcitation needed that Dave Cutler38 intended the initialism 'WNT' as a pun on VMS incrementing each letter by one. However the project was named NT OS/2 before receiving the Windows brand.39 One of the original OS/2 3.0 developers Mark Lucovsky states that the name was taken from the original target processorthe Intel i860 code-named N10 ('N-Ten').40 Various Microsoft publications including a 1998 question-and-answer session with Bill Gates reveal that the letters were expanded to 'New Technology' for marketing purposes but no longer carry any specific meaning.41 The letters were dropped from the name of Windows 2000 though Microsoft described the product as 'Built on NT technology.' See also Architecture of Windows NT Criticism of Microsoft Windows F6 disk Microsoft Windows NT Domain NTFS ReactOS (an open source project with the goal of providing binary- and device driver-level compatibility with Windows NT) Windows NT Startup Process Windows Preinstallation Environment Windows Server System Windows Embedded References Lextrait Vincent (January 2010). "The Programming Languages Beacon v10.0". http://www.lextrait.com/Vincent/implementations.html. Retrieved 4 January 2010.  Microsoft (2006-03-07). "Windows History". http://www.microsoft.com/windows/winhistorydesktop.mspx. Retrieved 2009-06-24.  a b Paul Thurrott (2003-01-24). "Windows Server 2003: The Road To Gold". http://www.winsupersite.com/reviews/winserver2k3gold1.asp. Retrieved 2010-01-05.  Krause Steve 2005 Windows NT "Paul Thurrott's SuperSite for Windows". Winsupersite.com. http://www.winsupersite.com/showcase/winvistaffx64.asp. Retrieved 2010-11-24.  "Chapter 28 - OS/2 Compatibility". 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Microsoft Windows Internals (Fourth Edition) Microsoft Press. ISBN 0-7356-1917-4 Andrew Pollack (1991-07-27). "Microsoft Widens Its Split With I.B.M. Over Software - New York Times". New York Times. http://query.nytimes.com/gst/fullpage.htmlres9D0CE0D81339F934A15754C0A967958260. Retrieved 2008-09-02.  "NT Drivers - FAQ - WDM". http://www.cmkrnl.com/faq02.html.  "Microsoft Releases Windows XP 64-Bit Edition Version 2003 to Manufacturing". March 2003. http://www.microsoft.com/presspass/press/2003/mar03/03-28WinXP64BitPR.mspx. Retrieved 2008-01-14.  "Windows Server 2008: Overview of Editions". www.microsoft.com. http://www.microsoft.com/windowsserver2008/en/us/editions-overview.aspx. Retrieved 2009-05-18.  a b "Operating System Versioning". Microsoft Developer Network. Microsoft. 2009-05-20. http://msdn.microsoft.com/en-gb/library/dd371754(VS.85).aspx. Retrieved 2009-07-06.  LeBlanc Brandon (2009-02-04). "A closer look at the Windows 7 SKUs". windowsteamblog.com. http://windowsteamblog.com/blogs/windows7/archive/2009/02/04/a-closer-look-at-the-windows-7-skus.aspx. Retrieved 2009-02-05.  Rothman Wilson (2009-06-02). "Windows 7 To Be Released October 22". Gizmodo. http://gizmodo.com/5275938/windows-7-to-be-released-october-22. Retrieved 2009-06-06.  "Windows Server 2008: Product Roadmap". www.microsoft.com. http://www.microsoft.com/windowsserver2008/en/us/roadmap.aspx. Retrieved 2009-05-18.  Russinovich Mark; Solomon David (2001-12) Windows XP: Kernel Improvements Create a More Robust Powerful and Scalable OS archived from the original on 2003-04-23 http://web.archive.org/web/20030424123732/http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel/ retrieved 2006-12-19  "Windows NT System Overview". Microsoft.com. http://www.microsoft.com/technet/archive/winntas/training/ntarchitectoview/ntarc2.mspx. Retrieved 2010-11-24.  Lucovsky Mark (2000-08-09). "Windows: A Software Engineering Odyssey". http://www.usenix.org/events/usenix-win2000/invitedtalks/lucovskyhtml/. Retrieved 2006-11-02.  "Intergraph Announces Port of Windows NT to SPARC Architecture". The Florida SunFlash. 1993-07-07. http://ftp.lanet.lv/ftp/sun-info/sunflash/1993/Jul/55.11-Sun-Intergraph:-SPARC-and-Windows-NT.  Microsoft demonstrates early build of Windows 8 Shaheen Gandhi. "Xbox Team: The Xbox Operating System". http://blogs.msdn.com/xboxteam/archive/2006/02/17/534421.aspx. Retrieved 2008-05-29.  Paul Thurott (December 1999). "The Road to Gold: The development of Windows 2000 Reviewed". http://www.winsupersite.com/reviews/win2kgold.asp. Retrieved 2008-01-05.  Raymond Chen (August 2008). "Windows Confidential". http://technet.microsoft.com/en-us/magazine/2008.08.windowsconfidential.aspx.  Paul Thurott (June 2000). "Windows 2000 Reportedly Returning to Alpha Platform". http://www.windowsitpro.com/Article/ArticleID/19345/19345.html. Retrieved 2008-01-05.  a b "Windows NT 3.5x Setup Troubleshooting Guide (MSKB 139733)". Support.microsoft.com. 2006-11-01. http://support.microsoft.com/kb/139733. Retrieved 2010-11-24.  "INFO:Windows NT 4.0 Setup Troubleshooting Guide". Support.microsoft.com. 2006-10-31. http://support.microsoft.com/kb/126690. Retrieved 2010-11-24.  a b "System requirements for Microsoft Windows 2000 operating systems". Support.microsoft.com. 2007-11-13. http://support.microsoft.com/kb/304297. Retrieved 2010-11-24.  "System requirements for Microsoft Windows XP operating systems". Support.microsoft.com. 2007-09-14. http://support.microsoft.com/kb/314865. Retrieved 2010-11-24.  "System requirements for Microsoft Windows Vista". Support.microsoft.com. 2007-11-13. http://support.microsoft.com/kb/919183. Retrieved 2010-11-24.  "Windows 7 system requirements". Microsoft. http://windows.microsoft.com/en-us/windows7/products/system-requirements. Retrieved 2009-08-30.  "Windows XP Professional System Requirements". http://www.microsoft.com/windowsxp/sysreqs/pro.mspx. Retrieved 7 March 2010.  "Windows 7 System Requirements". http://social.technet.microsoft.com/Forums/en/w7itproinstall/thread/9038c21f-5184-468c-bf5b-9f54bca70c5c. Retrieved 27 January 2011.  Zachary G. Pascal (1994). Show Stopper!: The Breakneck Race to Create Windows NT and the Next Generation at Microsoft. Free Press. ISBN 978-0029356715.  "Microsoft Windows NT OS/2 Design Workbook". http://americanhistory.si.edu/collections/object.cfmkey35&objkey124. Retrieved 2008-11-15.  "Paul Thurrott's History of Windows Server 2003: The Road To Gold". http://www.winsupersite.com/reviews/winserver2k3gold1.asp.  Gates Bill (1998-06-05). "Q&A: Protecting children from information on the Internet". http://www.microsoft.com/billgates/columns/1998q&a/QA5-6.asp. Retrieved 2005-06-26.  External links Official Page Windows NT and VMS: The Rest of the Story discussion of ancestry of NT by Mark Russinovich A Brief History of the Windows NT Operating System a Microsoft PressPass Fact Sheet v d eMicrosoft Windows family Versions  Comparison  Components  History  Timeline  Criticism DOS-Based Windows 1.0  Windows 2.0  Windows 2.1x  Windows 3.0  Windows 3.1x Windows 9x Windows 95  Windows 98 (development)  Windows Me Windows NT Earlier versions Windows NT 3.1  Windows NT 3.5  Windows NT 3.51  Windows NT 4.0  Windows 2000 Client releases Windows XP (editions x64  Media Center  development)  Windows Vista (editions  development)  Windows 7 (editions  development) Windows Server Server 2003  Server 2008 (Server 2008 R2  HPC Server 2008)  Home Server (Home Server 2011)  Essential Business Server  MultiPoint Server  Small Business Server Specialized Windows Embedded (POSReady)  Windows Preinstallation Environment  Windows Fundamentals for Legacy PCs Windows CE Auto  Windows CE 3.0  Windows CE 5.0 (Windows Mobile)  Windows CE 6.0 (Windows Phone 7)  Windows CE 7.0 Upcoming Windows 8 Cancelled Cairo  Nashville  Neptune  Odyssey Related topics OS/2  Windows Setup  Midori