Windows NT 3.1

Windows NT 3.1 (codenamed Razzle) is the first version of Windows NT. It had a very similar interface to Windows 3.1 but unlike Windows 3.1, Windows NT 3.1 was a complete 32-bit operating system while Windows 3.1 was mostly a constrictive 16-bit environment, although it also included 32-bit components to take advantage of the 386 processor. The name NT officially stands for "New Technology", although it has also been explained to stand for N-Ten, the codename for the Intel i860 processor that NT was originally designed for. It was succeeded by Windows NT 3.5 in 1994, and is the first version of Windows NT to support upgrade paths to Windows NT 4.0. Several update packages were released for NT 3.1 during its lifetime. Support for Windows NT 3.1 ended on 31 December 2001, alongside Windows 3.1.

Microsoft initially developed NT with the intention to use it as the base for OS/2 3.0, with the project being also known as NT OS/2 or Portable OS/2. However, with the high sales success of Windows 3.0, Microsoft changed the NT OS/2 plans to turn it into a 32-bit version of Windows with a subsystem to run existing OS/2 apps, which has contributed to the end of the IBM-Microsoft partnership. Afterwards, the project was commonly referred to as Advanced Windows in the press before the final name of Windows NT was revealed. The operating system was publicly demonstrated for the first time at COMDEX in October 1991. At the Win32 PDC conference in June 1992, Windows NT was demonstrated for the x86 and MIPS processors. On 27 July 1993, Windows NT 3.1 was released for x86 and MIPS, followed by the DEC Alpha version in September. The Workstation version was sold at $495 while the server version was $1495.

The boot screen only shows the processor count if a multiprocessor kernel and HAL is being used, which would be the case on systems like the Compaq SystemPro/XL and its clones.

System requirements
The x86 version of Windows NT 3.1 requires an 80386 processor, at least 16 MB of RAM, 75 MB of hard drive space, and a VGA or better display.

The MIPS and DEC Alpha versions require at least 16 MB of RAM and 92 MB of hard disk space.

For all versions, a CD-ROM drive is mandatory if installing from a CD-ROM.

Hardware compatibility
Windows NT 3.1 does not support processor generations higher than the original Pentium due to a faulty processor check during setup. Windows NT will state the processor as incompatible and abort setup without additional patching of setup files. Additionally, the x86 version of Windows NT 3.1 does not recognize more than 64 MB of RAM by default.

Windows NT 3.1 does not contain support for ATAPI CD-ROM drives by default, requiring either a SCSI CD-ROM controller or an ATAPI driver to be provided during setup in order to install.