Newer versions of Windows NT support 64-bit computing, with a 64-bit kernel and 64-bit memory addressing.

It has been suggested that Dave Cutler intended the initialism "WNT" as a play on VMS, incrementing each letter by one.

[10] 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.

[12] A 1991 video featuring Bill Gates and Microsoft products specifically says that "Windows NT stands for 'New Technology'".

[13] 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.

[14] 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".

[8][15] "NT" was a trademark of Northern Telecom (later Nortel), which Microsoft was forced to acknowledge on the product packaging.

An initial idea was to have a common code base with a custom Hardware Abstraction Layer (HAL) for each platform.

[18] 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.

[19] 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.

In Windows NT 4.0, the video, server, and printer spooler subsystems were moved into kernel mode.

Microsoft decided to create a portable operating system, compatible with OS/2 and POSIX and supporting multiprocessing, in October 1988.

[10] Although NT was not an exact clone of Cutler's previous operating systems, DEC engineers almost immediately noticed the internal similarities.

Kernel mode in Windows NT has full access to the hardware and system resources of the computer.

Once all the boot and system drivers have been loaded, the kernel starts the Session Manager Subsystem.

[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.

[50] However, for application compatibility reasons, Microsoft kept the major version number as 6 in releases following Vista,[51] but changed it later to 10 in Windows 10.

Starting with Windows 8.1, Microsoft changed the Version API Helper functions' behavior.

This work was initially based on the Intel i860-based Dazzle system and, later, the MIPS R4000-based Jazz platform.

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,[57] in conjunction with the company's planned introduction of UltraSPARC models in 1995,[58] but neither version was sold to the public as a retail product.

[60] On January 5, 2011, Microsoft announced that the next major version of the Windows NT family will include support for the ARM architecture.

[68][69] This continued for some time after Microsoft publicly announced that it was cancelling plans to ship 64-bit Windows for Alpha.