Windows NT

From Free net encyclopedia

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. The architecture complemented versions of Windows that were based on MS-DOS until 2001. Windows XP and Windows Server 2003 are the latest versions of Windows NT, though they are not branded as such for marketing purposes.

1 Development
2 Releases
- 2.1 Supported platforms
- 2.2 Hardware requirements
3 "NT" designation
4 See also
5 External links
6 Notes

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Development

When development started in November 1988, Windows NT (using protected mode) was to be known as OS/2 3.0, the third version of the operating system developed jointly by Microsoft and IBM. In addition to working on three versions of OS/2, Microsoft continued parallel development of the DOS-based and less resource-demanding Windows environment (using real mode). When Windows 3.0 was released in May 1990, it was 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 be as immediately popular as Microsoft's 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 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.

Windows NT's kernel mode code further distinguishes between the "kernel," whose prime purpose is to implement processor-architecture-dependent functions, and the "executive." This has led some writers to refer to the kernel as a microkernel, but the Windows NT kernel does not meet many of the criteria required to be a "microkernel" and this was not the intention of Windows NT's designers. Both the kernel and the executive are linked together into a single loaded module, ntoskrnl.exe; from outside this module there is little distinction between the kernel and the executive. Routines from each are directly callable, 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; it was this that allowed the late adoption of the Windows API. Windows NT was the first operating system to use Unicode internally.

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Releases

Windows NT Releases
NT Ver.	Marketing Name	Editions	Release Date	Build
NT 3.1	Windows NT 3.1	Workstation (named just Windows NT), Advanced Server	July 27 1993	528
NT 3.5	Windows NT 3.5	Workstation, Server	September 21 1994	807
NT 3.51	Windows NT 3.51	Workstation, Server	May 30 1995	1057
NT 4.0	Windows NT 4.0	Workstation, Server, Server Enterprise Edition, Terminal Server, Embedded	July 29 1996	1381
NT 5.0	Windows 2000	Professional, Server, Advanced Server, Datacenter Server	February 17 2000	2195
NT 5.1	Windows XP	Home, Professional, IA64, Media Center (2002, 2003, 2004 & 2005), Tablet PC, Starter, Embedded, N	October 25 2001	2600
NT 5.2	Windows Server 2003	Standard, Enterprise, Datacenter, Web, Small Business Server	April 24 2003	3790
NT 5.2	Windows XP (x64)	Professional x64 Edition	April 25 2005	3790
NT 6.0	Windows Vista	Starter, Home Basic, Home Premium, Business, Enterprise, Ultimate	Business: November 2006 Consumer: January 2007	Unknown
???	Windows Server "Longhorn" (codename)	Unknown	2007 (expected)	Unknown
???	Windows "Vienna" (codename)	Unknown	2011 (planned)	Unknown

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. The NT version is no longer marketed, but is said to reflect the degree of changes to the core of the operating system[1]. The build number is an internal figure used by Microsoft's developers.

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Supported platforms

Windows NT 3.1 ran on Intel IA-32 x86, DEC Alpha, and MIPS R4000 processors. Windows NT 3.51 added support for PowerPC processors. Intergraph Corporation ported Windows NT to its Clipper architecture and later SPARC, but neither version was sold to the public. Windows NT 4.0 was the last major release to support Alpha, MIPS, or PowerPC, though development of Windows 2000 for Alpha continued until 1999, when Compaq stopped support for Windows NT on that architecture. 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 3rd parties (Motorola, Intergraph, etc.) have few, if any, publicly available updates.

Windows XP 64-Bit, Windows Server 2003 Enterprise, and Windows Server 2003 Datacenter support Intel's IA-64 processors. As of April 25 2005 Microsoft had released four editions for "x64" (AMD64 or EM64T): Windows XP Professional x64 Edition, Windows Server 2003 Standard x64 Edition, Windows Server 2003 Enterprise x64 Edition, and Windows Server 2003 Datacenter x64 Edition.

The Xbox uses a heavily modified and stripped down Windows 2000 kernel. This kernel was heavily modified again for the Xbox 360 which runs on PowerPC. This version is not for separate sale, and little is known about it.

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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 current Draft Revision 0.8 (March 10 2006)[2] requires 512 MB of main memory for 6.0, an 8-fold increase on the previous release. No specifications for processors or free disk space have been published for Vista at the time of writing.

Windows NT desktop (x86) hardware requirements
NT Version	CPU	RAM	Disk space
NT Workstation 3.51	386, 25 MHz	12 MB	90 MB
NT 4.0 Workstation	486, 33 MHz	12 MB	110 MB
2000 Professional	Pentium, 133 MHz	32 MB	650 MB
XP Professional	Pentium MMX, 233 MHz	64 MB	1.5 GB
Vista	>=Pentium 4 or AMD Athlon 64	512 MB	3 GB

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"NT" designation

It is popularly believed that Dave Cutler intended the initialism "WNT" as a pun on VMS, incrementing each letter by one, similar to the apocryphal story of Arthur C. Clarke deriving HAL 9000's name by decrementing each letter of IBM. While this would have suited Cutler's sense of humor, the project's earlier name of NT OS/2 belies this theory. Another of the original OS/2 3.0 developers, Mark Lucovsky, states that the name was taken from the Intel i860 processor—code-named "N-Ten"—which served as the original target hardware. Various Microsoft publications, including a 1998 question-and-answer session with Bill Gates Template:Ref, reveal that the letters were expanded to "New Technology" for marketing purposes but no longer carry any specific meaning.

The letters were dropped from the name of Windows 2000, though the box contained the phrase "Built on NT technology". This action ostensibly reflected Microsoft's intent to unify its home and business lines, then represented by Windows 98 and Windows NT 4.0, but this goal would not be achieved until the introduction of Windows XP. Some believe this to be the result of a trademark dispute between Microsoft and Nortel as on the bottom of the Windows NT 4.0 product boxes is a notice explaining that "NT" is a trademark of Northern Telecom.

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External links

**History of Microsoft Windows**
MS-DOS–based: 1.0 • 2.0 • 3.0 • 3.1x • 95 • 98 • Me
NT-based: NT 3.1 • NT 3.5 • NT 3.51 • NT 4.0 • 2000 • XP • Server 2003
CE-based: CE 3.0 • Mobile • CE 5.0
Forthcoming: Vista • FLP (thin-client) • Server "Longhorn" • "Fiji" • "Vienna"