Windows NT#Major features

Windows NT is a group or family of products—like Windows is a group or family. Windows NT is a sub-grouping of Windows.

The first version of Windows NT, 3.1, was produced for workstation and server computers. It was commercially focused—and intended to complement consumer versions of Windows that were based on MS-DOS (including Windows 1.0 through Windows 3.1x). In 1996, Windows NT 4.0 was released, including the new shell from Windows 95.

Eventually, Microsoft incorporated the Windows NT technology into the Windows product line for personal computing and deprecated the Windows 9x family. Starting with Windows 2000,{{cite press release|url=http://www.microsoft.com/en-us/news/press/1998/oct98/nt5.aspx|title=Microsoft Renames Windows NT 5.0 Product Line to Windows 2000; Signals Evolution of Windows NT Technology Into Mainstream|date=October 27, 1998|publisher=Microsoft|access-date=April 23, 2014|archive-date=June 10, 2014|archive-url=https://web.archive.org/web/20140610224640/http://www.microsoft.com/en-us/news/press/1998/oct98/nt5.aspx|url-status=dead}} "NT" was removed from the product name yet is still in several low-level places in the system—including for a while as part of the product version.{{cite web|url=https://msdn.microsoft.com/en-us/library/vstudio/system.operatingsystem.versionstring%28v=vs.100%29.aspx|title=OperatingSystem.VersionString Property|access-date=November 10, 2014|website=MSDN|publisher=Microsoft|archive-date=May 15, 2013|archive-url=https://web.archive.org/web/20130515073034/http://msdn.microsoft.com/en-us/library/vstudio/system.operatingsystem.versionstring(v=vs.100).aspx|url-status=live}}

Versions of Windows NT are installed using Windows Setup, which, starting with Windows Vista, uses the Windows Preinstallation Environment, which is a lightweight version of Windows NT made for deployment of the operating system.{{Citation needed|date=February 2025}}

Since Windows Vista, the Windows installation files, as well as the preinstallation environment used to install Windows, are stored in the Windows Imaging Format. It is possible to use the Deployment Image Servicing and Management (DISM) tool to install Windows from the command line and skip the GUI installer.{{Citation needed|date=February 2025}}

It has been suggested that Dave Cutler intended the initialism "WNT" as a play on VMS, incrementing each letter by one.{{cite book|last=Zachary|first=G Pascal|title=Show Stopper!: The Breakneck Race to Create Windows NT and the Next Generation at Microsoft|year=1994|publisher=Free Press|isbn=978-0-02-935671-5|url-access=registration|url=https://archive.org/details/showstopperbreak00zach}} However, the project was originally intended as a follow-on to OS/2 and was referred to as "NT OS/2" before receiving the Windows brand.{{cite web|work=American history|publisher=Smithsonian|title=Microsoft Windows NT OS/2 Design Workbook|url=http://americanhistory.si.edu/collections/search/object/nmah_742559|access-date=March 17, 2017}} Two of the original NT developers, Mark Lucovsky and Dave W. Plummer,{{Cite tweet |number=1895871194290929872 |user=davepl1968 |title=Did You Know? Windows NT does not stand for "New Technology". It stands for NTen, or N10, which was the codename for the Intel i860 chip where NT development started. |date=March 1, 2025 |access-date=April 9, 2025}} state that the name was taken from the original target processor—the Intel i860, code-named N10 ("N-Ten").{{cite web|url=https://www.itprotoday.com/windows-server/windows-server-2003-road-gold-part-one-early-years|title=Windows Server 2003: The Road To Gold|date=January 24, 2003|first=Paul|last=Thurrott|website=ITPro Today}} A 1991 video featuring Bill Gates and Microsoft products specifically says that "Windows NT stands for 'New Technology{{'"}}.{{Cite AV media |url=https://www.youtube.com/watch?v=SzSCwuPBsVs&t=528s |title=Microsoft Windows 3 and NT, 1991, Part 3 |date=December 3, 2008 |last=kaleidomagic |access-date=April 9, 2025 |via=YouTube}} Seven years later in 1998, during a question-and-answer (Q&A) session, he then revealed that the letters were previously expanded to such but no longer carry any specific meaning.{{cite web|last=Gates|first=Bill|date=June 5, 1998|archive-url=https://web.archive.org/web/20010526174935/http://www.microsoft.com/billgates/columns/1998q%26a/QA5-6.asp|archive-date=May 26, 2001|url=http://www.microsoft.com/billgates/columns/1998q&a/QA5-6.asp|title=Q&A: Protecting children from information on the Internet|website=Microsoft|access-date=June 26, 2005|url-status=dead}} The letters were dropped from the names of releases from Windows 2000 and later, though Microsoft described that product as being "Built on NT Technology".{{cite web|url=http://www.microsoft.com/presspass/features/1998/10-27winma.mspx|title=Windows 2000 is a name that reflects NT's continued move to the technology mainstream|publisher=Microsoft|date=October 27, 1998|access-date=November 13, 2011|archive-date=October 7, 2008|archive-url=https://web.archive.org/web/20081007063504/http://www.microsoft.com/presspass/features/1998/10-27winma.mspx|url-status=dead}}

"NT" was a trademark of Northern Telecom (later Nortel), which Microsoft was forced to acknowledge on the product packaging.

One of the main purposes of NT is hardware and software portability. Various versions of NT family operating systems have been released for a variety of processor architectures, initially IA-32, MIPS, and DEC Alpha, with PowerPC, Itanium, x86-64 and ARM supported in later releases. An initial idea was to have a common code base with a custom Hardware Abstraction Layer (HAL) for each platform. However, support for MIPS, Alpha, and PowerPC was later dropped in Windows 2000. Broad software compatibility was initially achieved with support for several API "personalities", including Windows API, POSIX,{{cite web|url=http://www.winsupersite.com/showcase/winvista_ff_x64.asp|title=Paul Thurrott's SuperSite for Windows|publisher=Win super site|access-date=November 24, 2010|archive-date=July 30, 2008|archive-url=https://web.archive.org/web/20080730041953/http://www.winsupersite.com/showcase/winvista_ff_x64.asp|url-status=live}} and OS/2 APIs{{citation|title=MS Windows NT 4 Workstation|type=resource kit|chapter-url=http://www.microsoft.com/resources/documentation/windowsnt/4/workstation/reskit/en-us/os2comp.mspx?mfr=true|chapter=28 – OS/2 Compatibility|publisher=Microsoft|access-date=November 24, 2010|archive-url=https://web.archive.org/web/20160303170554/http://www.microsoft.com/resources/documentation/windowsnt/4/workstation/reskit/en-us/os2comp.mspx?mfr=true|archive-date=March 3, 2016|url-status=dead}}—the latter two were phased out starting with Windows XP.{{cite web|url=http://support.microsoft.com/kb/308259|title=POSIX and OS/2 are not supported in Windows XP or in Windows Server 2003|work=Support|publisher=Microsoft|date=November 5, 2007|access-date=November 24, 2010|archive-date=October 19, 2004|archive-url=https://web.archive.org/web/20041019061658/http://support.microsoft.com/kb/308259|url-status=live}} Partial MS-DOS and Windows 16-bit compatibility is achieved on IA-32 via an integrated DOS Virtual Machine—although this feature is not available on other architectures.{{cite web|url=http://download.microsoft.com/download/8/1/e/81eabaf4-1907-4967-87a9-be242b1402e9/x64_Editions_Deployment.doc|title=x64 editions deployment|access-date=November 24, 2010|archive-date=December 18, 2014|archive-url=https://web.archive.org/web/20141218234430/http://download.microsoft.com/download/8/1/e/81eabaf4-1907-4967-87a9-be242b1402e9/x64_Editions_Deployment.doc|url-status=dead}}

NT has supported per-object (file, function, and role) access control lists allowing a rich set of security permissions to be applied to systems and services. NT

has also supported Windows network protocols, inheriting the previous OS/2 LAN Manager networking, as well as TCP/IP networking (for which Microsoft used to implement a TCP/IP stack derived at first from a STREAMS-based stack from Spider Systems, then later rewritten in-house).{{cite web|last=Barr|first=Adam|url=http://www.kuro5hin.org/story/2001/6/19/05641/7357|title=Microsoft, TCP/IP, Open Source, and Licensing|website=Kuro5hin|date=June 19, 2001|access-date=February 22, 2013|archive-url=https://web.archive.org/web/20151229084950/http://www.kuro5hin.org/story/2001/6/19/05641/7357|archive-date=December 29, 2015}}

Windows NT 3.1 was the first version of Windows to use 32-bit flat virtual memory addressing on 32-bit processors. Its companion product, Windows 3.1, used segmented addressing and switches from 16-bit to 32-bit addressing in pages.

Windows NT 3.1 featured a core kernel providing a system API, running in supervisor mode (ring 0 in x86; referred to in Windows NT as "kernel mode" on all platforms), and a set of user-space environments with their own APIs which included the new Win32 environment, an OS/2 1.3 text-mode environment and a POSIX environment. The full preemptive multitasking kernel could interrupt running tasks to schedule other tasks, without relying on user programs to voluntarily give up control of the CPU, as in Windows 3.1 Windows applications (although MS-DOS applications were preemptively multitasked in Windows starting with Windows/386).

Notably, in Windows NT 3.x, several I/O driver subsystems, such as video and printing, were user-mode subsystems. In Windows NT 4.0, the video, server, and printer spooler subsystems were moved into kernel mode. Windows NT's first GUI was strongly influenced by (and programmatically compatible with) that from Windows 3.1; Windows NT 4.0's interface was redesigned to match that of the brand-new Windows 95, moving from the Program Manager to the Windows shell design.

NTFS, a journaled, secure file system, is a major feature of NT. Windows NT also allows for other installable file systems; NT can also be installed on FAT file systems, and versions 3.1, 3.5, and 3.51 could be installed on HPFS file systems.{{cite web|url=https://learn.microsoft.com/en-us/troubleshoot/windows-client/backup-and-storage/fat-hpfs-and-ntfs-file-systems|title=Overview of FAT, HPFS, and NTFS File Systems|website=Microsoft Learn|date=September 23, 2021|publisher=Microsoft|access-date=November 29, 2023|archive-date=December 11, 2023|archive-url=https://web.archive.org/web/20231211011049/https://learn.microsoft.com/en-us/troubleshoot/windows-client/backup-and-storage/fat-hpfs-and-ntfs-file-systems|url-status=live}}

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.{{cite web|url=http://www.cmkrnl.com/faq02.html|title=NT Drivers – FAQ – WDM|website=CMKrnl|archive-url=https://web.archive.org/web/20090421010210/http://www.cmkrnl.com/faq02.html|archive-date=April 21, 2009|url-status=dead}} 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.

File:Windows NT logo.svg]]

Microsoft decided to create a portable operating system, compatible with OS/2 and POSIX and supporting multiprocessing, in October 1988.{{Citation|first=Dave|last=Cutler|author-link=Dave Cutler|contribution=Preface|editor1-first=Mark|editor1-last=Russinovich|editor1-link=Mark Russinovich|editor2-first=David A|editor2-last=Solomon|editor2-link=David A. Solomon|title=Microsoft Windows Internals|year=2005|edition=fourth|publisher=Microsoft Press|isbn=0-7356-1917-4|url-access=registration|url=https://archive.org/details/isbn_9780735619173}}. When development started in November 1989, Windows NT was to be known as OS/2 3.0,{{cite web|url=https://query.nytimes.com/gst/fullpage.html?res=9D0CE0D81339F934A15754C0A967958260|title=Microsoft Widens Its Split With IBM Over Software|date=July 27, 1991|first=Andrew|last=Pollack|newspaper=The New York Times|access-date=September 2, 2008|archive-date=November 2, 2010|archive-url=https://web.archive.org/web/20101102233112/http://query.nytimes.com/gst/fullpage.html?res=9D0CE0D81339F934A15754C0A967958260|url-status=live}} 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. 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 3.0 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,{{cite web|website=IT Pro|url=http://www.itprotoday.com/windows-client/windows-nt-and-vms-rest-story|title=Windows NT and VMS: The Rest of the Story|first=Mark|last=Russinovich|date=November 30, 1998|access-date=January 2, 2018}} VAXELN and RSX-11, but also an unreleased object-based operating system developed by Cutler at Digital codenamed MICA.{{cite web|url=http://neilrieck.net/docs/Windows-NT_is_VMS_re-implemented.html|title='Windows-NT' is 'VMS Reimplemented' (sort of)|author=Neil Rieck|access-date=February 9, 2023|archive-date=February 9, 2023|archive-url=https://web.archive.org/web/20230209212816/http://neilrieck.net/docs/Windows-NT_is_VMS_re-implemented.html|url-status=live}} The team was joined by selected members of the disbanded OS/2 team, including Moshe Dunie.

File:Windows 2000 architecture.svg

Although NT was not an exact clone of Cutler's previous operating systems, DEC engineers almost immediately noticed the internal similarities. Parts of VAX/VMS Internals and Data Structures, published by Digital Press, accurately describe Windows NT internals using VMS terms. Furthermore, parts of the NT codebase's directory structure and filenames matched that of the MICA codebase. Instead of a lawsuit, Microsoft agreed to pay DEC $65–100 million, help market VMS, train Digital personnel on Windows NT, and continue Windows NT support for the DEC Alpha.{{r|russinovich19981130}}

Windows NT and VMS memory management, processes, and scheduling are very similar. Windows NT's process management differs by implementing threading, which DEC did not implement until VMS 7.0 in 1995.

Like VMS,{{r|russinovich19981130}} Windows NT's kernel mode code 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 was influenced by the Mach microkernel developed by Richard Rashid at Carnegie Mellon University,{{cite book|date=December 1, 1999|title=Supporting Windows NT and 2000 Workstation and Server|chapter=Windows NT Basics|chapter-url=https://learn.microsoft.com/en-us/previous-versions/cc768132(v=technet.10)|first=Jim|last=Mohr|quote=The technique that Windows NT uses is called a 'microkernel' and was influenced by the Mach microkernel developed at Carnegie Mellon University.|access-date=November 29, 2023|publisher=Prentice Hall|isbn=978-0-13-083068-5|archive-date=March 6, 2024|archive-url=https://web.archive.org/web/20240306032531/https://learn.microsoft.com/en-us/previous-versions/cc768132(v=technet.10)|url-status=live}} but 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 UCS-2 and UTF-16 internally.{{citation needed|date=March 2021}}

{{main|Architecture of Windows NT}}

Windows NT uses a layered design architecture that consists of two main components, user mode and kernel mode. Programs and subsystems in user mode are limited in terms of what system resources they have access to, while the kernel mode has unrestricted access to the system memory and external devices. Kernel mode in Windows NT has full access to the hardware and system resources of the computer. The Windows NT kernel is a hybrid kernel; the architecture comprises a simple kernel, hardware abstraction layer (HAL), drivers, and a range of services (collectively named Executive), which all exist in kernel mode.{{cite book |last=Finnel |first=Lynn |date=2000 |title=MCSE Exam 70-215, Microsoft Windows 2000 Server |publisher=Microsoft Press |isbn=1-57231-903-8 |at=Chapter 1: Introduction to Microsoft Windows 2000, pp. 7–18}}

The booting process of Windows NT begins with NTLDR in versions before Vista and the Windows Boot Manager in Vista and later.{{Cite web|title=Boot Sequence of Windows Multi-Boot - Multibooters.com|url=http://www.multibooters.com/guides/boot-sequence-of-mixed-windows-multiboot.html|access-date=November 19, 2020|website=www.multibooters.com|archive-date=February 6, 2022|archive-url=https://web.archive.org/web/20220206034848/http://www.multibooters.com/guides/boot-sequence-of-mixed-windows-multiboot.html|url-status=live}} The boot loader is responsible for accessing the file system on the boot drive, starting the kernel, and loading boot-time device drivers into memory. Once all the boot and system drivers have been loaded, the kernel starts the Session Manager Subsystem. This process launches winlogon, which allows the user to login. Once the user is logged in File Explorer is started, loading the graphical user interface of Windows NT.

Windows NT is written in C and C++, with a very small amount written in assembly language.{{cite web|url=https://learn.microsoft.com/en-us/previous-versions/cc767881(v=technet.10)|title=Windows NT System Overview|website=Microsoft Docs|date=February 20, 2014 |publisher=Microsoft|access-date=August 16, 2023}} C is mostly used for the kernel code while C++ is mostly used for user-mode code. Assembly language is avoided where possible because it would impede portability.{{cite AV media|last1=Chen|first1=Raymond|title=One Dev Question with Raymond Chen – What Programming Language is Windows Written In?|url=https://learn.microsoft.com/en-us/shows/one-dev-minute/one-dev-question-raymond-chen-programming-language-windows-written-in|website=Microsoft Learn|publisher=Microsoft|date=September 28, 2016|access-date=October 15, 2022|archive-date=October 15, 2022|archive-url=https://web.archive.org/web/20221015183740/https://learn.microsoft.com/en-us/shows/one-dev-minute/one-dev-question-raymond-chen-programming-language-windows-written-in|url-status=live}}

{{see also|List of Microsoft Windows versions}}

The following are the releases of Windows based on the Windows NT technology.

Windows NT 3.1 to 3.51 incorporated the Program Manager and File Manager from the Windows 3.1 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. Also the Novell IPX protocol was apparently licensed only to 3.1 versions of Windows software.{{Citation needed|date=July 2008}}

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.{{citation|last1=Russinovich|first1=Mark|last2=Solomon|first2=David|date=December 2001|publisher=Microsoft|url=http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel|series=Developer network|title=Windows XP: Kernel Improvements Create a More Robust, Powerful, and Scalable OS|newspaper=MSDN mag|access-date=December 19, 2006|archive-url=https://web.archive.org/web/20030424123732/http://msdn.microsoft.com/msdnmag/issues/01/12/XPKernel|archive-date=April 24, 2003}} However, for application compatibility reasons, Microsoft kept the major version number as 6 in releases following Vista,{{cite web|title=Why 7?|publisher=Microsoft|url=http://windowsteamblog.com/windows/archive/b/windowsvista/archive/2008/10/14/why-7.aspx|work=Windows Team Blog|date=October 14, 2008|access-date=September 14, 2019|archive-url=https://web.archive.org/web/20120415233158/http://windowsteamblog.com/windows/archive/b/windowsvista/archive/2008/10/14/why-7.aspx|archive-date=April 15, 2012}} but changed it later to 10 in Windows 10. The build number is an internal identifier used by Microsoft's developers and beta testers.

Starting with Windows 8.1, Microsoft changed the Version API Helper functions' behavior. If an application is not manifested for Windows 8.1 or later, the API will always return version 6.2, which is the version number of Windows 8.{{cite web|url=https://docs.microsoft.com/en-us/windows/win32/sysinfo/operating-system-version|title=Operating System Version|date=September 15, 2020|work=Microsoft Developer Network|publisher=Microsoft|access-date=November 24, 2020|archive-date=January 2, 2021|archive-url=https://web.archive.org/web/20210102160354/https://docs.microsoft.com/en-us/windows/win32/sysinfo/operating-system-version|url-status=live}}{{cite web|url=https://docs.microsoft.com/en-us/windows/win32/w8cookbook/operating-system-version-changes-in-windows-8-1|title=Operating system version changes in Windows 8.1 and Windows Server 2012 R2|date=May 31, 2018|work=Microsoft Developer Network|publisher=Microsoft|access-date=November 24, 2020|archive-date=December 8, 2020|archive-url=https://web.archive.org/web/20201208202531/https://docs.microsoft.com/en-us/windows/win32/w8cookbook/operating-system-version-changes-in-windows-8-1|url-status=live}} This is because the manifest feature was introduced with Windows 8.1,{{cite web|url=https://docs.microsoft.com/en-us/windows/compatibility/application-executable-manifest|title=App (executable) manifest|publisher=Microsoft|date=July 11, 2018|access-date=November 24, 2020|archive-date=October 1, 2020|archive-url=https://web.archive.org/web/20201001082723/https://docs.microsoft.com/en-us/windows/compatibility/application-executable-manifest|url-status=live}} to replace GetVersion and related functions.{{cite web|url=https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getversion|title=GetVersion function (sysinfoapi.h)|publisher=Microsoft|date=December 5, 2018|access-date=November 24, 2020}}

In order to prevent Intel x86-specific code from slipping into the operating system, due to developers being 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.{{cite web|last=Lucovsky|first=Mark|date=August 9, 2000|url=http://www.usenix.org/events/usenix-win2000/invitedtalks/lucovsky_html|title=Windows: A Software Engineering Odyssey|access-date=November 2, 2006}}

Windows NT 3.1 was released for Intel x86 PC compatible and PC-98 platforms, and for 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 ThinkPad Power Series 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 an intention to port Windows NT 3.51 to Sun Microsystems' SPARC architecture,{{cite web|url=http://ftp.lanet.lv/ftp/sun-info/sunflash/1993/Jul/55.11-Sun-Intergraph:-SPARC-and-Windows-NT|title=Intergraph Announces Port of Windows NT to SPARC Architecture|date=July 7, 1993|work=The Florida SunFlash|access-date=August 8, 2007|archive-date=December 28, 2018|archive-url=https://web.archive.org/web/20181228125839/http://ftp.lanet.lv/ftp/sun-info/sunflash/1993/Jul/55.11-Sun-Intergraph:-SPARC-and-Windows-NT|url-status=live}} in conjunction with the company's planned introduction of UltraSPARC models in 1995,{{ cite news|title=New ports of call for Windows NT|work=Personal Computer World|date=October 1993|pages=174}} 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,{{cite web|title=Can Linux break Intel's hold on the market?|url=http://edition.cnn.com/TECH/computing/9909/03/linux.alpha.idg/index.html|website=CNN|date=September 3, 1999|first=Nicholas|last=Petreley|access-date=November 26, 2013|archive-date=December 3, 2013|archive-url=https://web.archive.org/web/20131203012412/http://edition.cnn.com/TECH/computing/9909/03/linux.alpha.idg/index.html|url-status=dead}} even though the Alpha NT 5 (Windows 2000) release had reached RC1 status.{{cite web|author=Aaron Sakovich|publisher=The AlphaNT Source|year=2001|url=http://www.alphant.com/articles/windows2000.html|title=Windows 2000?|access-date=January 1, 2007|archive-url=https://web.archive.org/web/20080708183609/http://www.alphant.com/articles/windows2000.html|archive-date=July 8, 2008|url-status=dead}}

On January 5, 2011, Microsoft announced 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.{{Cite web|url=http://www.winrumors.com/microsoft-demonstrates-early-build-of-windows-8|title=Microsoft demonstrates early build of Windows 8|website=winrumors.com|archive-url=https://web.archive.org/web/20110109033638/http://www.winrumors.com/microsoft-demonstrates-early-build-of-windows-8|archive-date=January 9, 2011|date=January 5, 2011|first=Tom|last=Warren|url-status=dead}} This eventually led to the commercial release of the Windows 8-derived Windows RT on October 26, 2012, and the use of Windows NT, rather than Windows CE, in Windows Phone 8.

The original Xbox and Xbox 360 run a custom operating system based upon a heavily modified version of Windows 2000, an approach that Microsoft engineer Don Box called "fork and run".{{cite web | url = https://arstechnica.com/information-technology/2016/05/onecore-to-rule-them-all-how-windows-everywhere-finally-happened/2/ | title = OneCore to rule them all: How Windows Everywhere finally happened | date = May 20, 2016 | access-date = November 30, 2020 | work = Ars Technica | archive-date = May 21, 2016 | archive-url = https://web.archive.org/web/20160521184950/https://arstechnica.com/information-technology/2016/05/onecore-to-rule-them-all-how-windows-everywhere-finally-happened/2/ | url-status = live }}{{cite web |url=https://www.theverge.com/2020/5/21/21265995/xbox-source-code-leak-original-console-windows-3-5 |title=Xbox and Windows NT 3.5 source code leaks online |first=Tom |last=Warren |date=May 21, 2020 |access-date=August 4, 2024 |archive-date=June 4, 2020 |archive-url=https://web.archive.org/web/20200604083358/https://www.theverge.com/2020/5/21/21265995/xbox-source-code-leak-original-console-windows-3-5 |url-status=live }} It exports APIs similar to those found in Microsoft Windows, such as Direct3D.{{cite web |last1=Trinder |first1=Garry |title=The Xbox Operating System |url=https://blogs.msdn.microsoft.com/xboxteam/2006/02/17/the-xbox-operating-system/ |website=Xbox Engineering |date=February 17, 2006 |publisher=MSDN |access-date=October 31, 2018 |archive-url=https://web.archive.org/web/20181102200600/https://blogs.msdn.microsoft.com/xboxteam/2006/02/17/the-xbox-operating-system/ |archive-date=November 2, 2018 |url-status=live }} The Xbox One and Xbox Series X/S consoles use a stripped-down version of the Windows operating system.{{Cite web|url=http://www.gamespot.com/articles/xbox-one-is-literally-a-windows-device/1100-6430425|title=Xbox One Is "Literally a Windows Device"|access-date=April 18, 2020|archive-date=December 27, 2015|archive-url=https://web.archive.org/web/20151227060719/http://www.gamespot.com/articles/xbox-one-is-literally-a-windows-device/1100-6430425|url-status=live}}

Windows 11 is the first non-server version of Windows NT that does not support 32-bit platforms.{{Cite web|title=Windows 11 Specifications|url=https://www.microsoft.com/en-us/windows/windows-11-specifications|url-status=live|archive-url=https://web.archive.org/web/20210625033355/https://www.microsoft.com/en-us/windows/windows-11-specifications|archive-date=June 25, 2021|access-date=June 25, 2021|website=microsoft.com}}{{Cite web|title=Windows minimum hardware requirements|url=https://learn.microsoft.com/en-us/windows-hardware/design/minimum/minimum-hardware-requirements-overview|access-date=August 18, 2023|website=Microsoft Docs|date=September 2021|archive-date=August 19, 2023|archive-url=https://web.archive.org/web/20230819015535/https://learn.microsoft.com/en-us/windows-hardware/design/minimum/minimum-hardware-requirements-overview|url-status=live}}

The 64-bit versions of Windows NT were originally intended to run on Itanium and DEC Alpha; the latter was used internally at Microsoft during early development of 64-bit Windows.{{cite web|first=Paul|last=Thurott|date=December 15, 1999|url=http://www.itprotoday.com/windows-server/road-gold-look-development-windows-2000-0|title=Road to Gold: A Look at the Development of Windows 2000|access-date=January 2, 2018|archive-date=June 12, 2018|archive-url=https://web.archive.org/web/20180612143638/http://www.itprotoday.com/windows-server/road-gold-look-development-windows-2000-0|url-status=live}}{{cite magazine|first=Raymond|last=Chen|date=August 2008|magazine=TechNet Magazine|publisher=Microsoft|url=https://learn.microsoft.com/en-us/previous-versions/technet-magazine/cc718978(v=msdn.10)|department=Windows Confidential|title=Building on the Past|access-date=November 30, 2023|archive-date=January 3, 2024|archive-url=https://web.archive.org/web/20240103141034/https://learn.microsoft.com/en-us/previous-versions/technet-magazine/cc718978%28v=msdn.10%29|url-status=live}} This continued for some time after Microsoft publicly announced that it was cancelling plans to ship 64-bit Windows for Alpha.{{cite web|first=Paul|last=Thurott|date=June 21, 2000|url=http://www.itprotoday.com/windows-8/windows-2000-reportedly-returning-alpha-platform|title=Windows 2000 Reportedly Returning to Alpha Platform|access-date=January 2, 2018|quote=UPDATE: Compaq has apparently denied that any work is being done on Windows 2000/64 for the Alpha.|archive-date=January 3, 2018|archive-url=https://web.archive.org/web/20180103074520/http://www.itprotoday.com/windows-8/windows-2000-reportedly-returning-alpha-platform|url-status=live}} Because of this, Alpha versions of Windows NT are 32-bit only.

While Windows 2000 only supports Intel IA-32 (32-bit), Windows XP, Server 2003, Server 2008 and Server 2008 R2 each have one edition dedicated to Itanium-based systems.{{cite web|title=Windows Server 2008 for Itanium-Based Systems Feature Support|url=https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc772344(v=ws.10)|website=Microsoft Learn|date=July 2, 2012|publisher=Microsoft|access-date=November 29, 2023|archive-date=March 5, 2024|archive-url=https://web.archive.org/web/20240305051228/https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc772344(v=ws.10)|url-status=live}}{{cite web|title=Windows Server 2008 R2 for Itanium-Based Systems|url=http://www.microsoft.com/en-us/server-cloud/windows-server/2008-r2-itanium.aspx|work=Windows Server Editions|publisher=Microsoft|access-date=October 14, 2011|archive-date=October 9, 2011|archive-url=https://web.archive.org/web/20111009235829/http://www.microsoft.com/en-us/server-cloud/windows-server/2008-r2-itanium.aspx|url-status=live}} In comparison with Itanium, Microsoft adopted x64 on a greater scale: every version of Windows since Windows XP (which has a dedicated x64 edition){{cite web|title=Microsoft Windows XP 64-Bit Edition|url=https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-xp/bb457053(v=technet.10)|website=Microsoft Learn|publisher=Microsoft|access-date=November 29, 2023|date=August 15, 2001}} has x64 editions.{{cite web|title=Comparison of Windows Server 2003 Editions|url=https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc758523(v=ws.10)|work=Microsoft Learn|date=October 8, 2009|publisher=Microsoft|access-date=November 29, 2023|archive-date=January 30, 2024|archive-url=https://web.archive.org/web/20240130213926/https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2003/cc758523(v=ws.10)|url-status=live}}{{cite web|title=A description of the x64-based versions of Windows Server 2003 and of Windows XP Professional x64 Edition|url=http://support.microsoft.com/kb/888733|work=Microsoft Support Center|publisher=Microsoft|access-date=October 14, 2011|archive-url=https://web.archive.org/web/20111017165559/http://support.microsoft.com/kb/888733|archive-date=October 17, 2011|url-status=dead}}

The first version of Windows NT to support ARM64 devices with Qualcomm processors was Windows 10, version 1709.{{cite web|title=Windows 10 1709 Supported Qualcomm Processors|date=November 10, 2021|url=https://learn.microsoft.com/en-us/windows-hardware/design/minimum/supported/windows-10-1709-supported-qualcomm-processors|access-date=November 27, 2022|archive-date=November 27, 2022|archive-url=https://web.archive.org/web/20221127180706/https://learn.microsoft.com/en-us/windows-hardware/design/minimum/supported/windows-10-1709-supported-qualcomm-processors|url-status=live}} This is a full version of Windows, rather than the cut-down Windows RT.

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 tenfold increase in free disk space alone over the previous version, and the 2021 10.0 (11) release which excludes most systems built before 2018.

• F6 disk
• Windows domain
• ReactOS (an open source project with the goal of providing binary- and device driver-level compatibility with Windows NT)
• Windows Preinstallation Environment
• Microsoft Servers

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{{reflist}}

• {{Citation|url=http://www.microsoft.com/windows|title=Windows|publisher=Microsoft|type=official page}}.
• {{Citation|newspaper=Win 2000|archive-url=https://web.archive.org/web/20020503172231/http://www.win2000mag.com/Articles/Print.cfm?ArticleID=4494|title=Windows NT and VMS: The Rest of the Story|type=discussion of ancestry of NT|first=Mark|last=Russinovich|archive-date=May 3, 2002|url=http://www.win2000mag.com/Articles/Print.cfm?ArticleID=4494}}.
• {{Citation|archive-url=https://web.archive.org/web/20040610122846/http://www.microsoft.com/presspass/features/1998/winntfs.asp|title=A Brief History of the Windows NT Operating System|publisher=Microsoft PressPass|type=fact sheet|year=1998|archive-date=June 10, 2004|url=http://www.microsoft.com/presspass/features/1998/winntfs.asp}}.

{{Microsoft Windows family}}

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Category:1993 software

NT

Category:Advanced RISC Computing