Microsoft Windows NT 3.1

1993, October 24

Windows NT 3.1 is the first major release of the Windows NT operating system developed by Microsoft, released on July 27, 1993. It marked the company's entry into the corporate computing environment, designed to support large networks and to be portable, compiled for Intel x86, DEC Alpha and MIPS based workstations and servers. It was Microsoft's first 32-bit operating system, providing advantages over the constrictive 16-bit architecture of previous versions of Windows that relied on DOS, but retaining a desktop environment familiar to Windows 3.1 users.

Windows NT began as a rewrite of the OS/2 operating system, which Microsoft had co-developed with IBM but failed to gain much traction against Unix, with vendor Sun Microsystems dominating the market for powerful desktop workstations. For several reasons, including the market success of Windows 3.0 in 1990, Microsoft decided to advance Windows rather than OS/2 and relinquished their OS/2 development responsibilities. By extending the Windows brand and beginning NT at version 3.1, like Windows 3.1 which had established brand recognition and market share, Microsoft implied that consumers should expect a familiar user experience. The name Windows NT ("New Technology") advertised that this was a re-engineered version of Windows.

First publicly demonstrated at Comdex 1991, NT 3.1 was released in 1993 in two editions: Workstation and Advanced Server. When Windows NT premiered, their sales were limited by high system requirements, and a general lack of 32-bit applications to take advantage of the OS's data processing capabilities. It sold about 300,000 copies before it was succeeded by Windows NT 3.5 in 1994. On December 31, 2000, Microsoft declared Windows NT 3.1 obsolete and stopped providing support and updates for the system.

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.