Info Tech Guide

Microsoft Windows NT Version 3.1

In May 1993 the first Windows NT (New Technology) version 3.1 came as a Workstation (Client) and Advanced Server operating system for Intel x86 and RISC architecture to the market. It is the indirect successor to Windows 3.0 and OS/2 2.0 in the new NT product line for high demands on stability. It allows 32-bit applications and makes them available each up to 2 GB of virtual memory. The protected memory area ensures the stability of Windows NT if an application has a crash. To protect against power outages, the use of a UPS is supported. The operating system is suitable as a network client and in the office. The system structure is based on a micro-kernel with support for up to 2 CPUs and can address a maximum of 64 MB of RAM. The file systems NTFS, HPFS and FAT-16 are fully supported. This version of Windows does not support Plug and Play.


Minimum requirement of hardware is at least an Intel 386 microprocessor with 25 MHz, 12 MB of RAM and a hard drive with 75 MB of free disk space. For the RISC architecture is suitable for example one Mips R4000 processor, at least 16 MB of RAM and 92 MB free hard disk space.

Windows NT 3.1 (Microsoft marketing wanted Windows NT to appear to be a continuation of Windows 3.1) arrived in Beta form to developers at the July 1992 Professional Developers Conference in San Francisco. Microsoft announced at the conference its intentions to develop a successor to both Windows NT and Windows 3.1's replacement (Windows 95, code-named Chicago), which would unify the two into one operating system. This successor was codenamed Cairo. In hindsight, Cairo was a much more difficult project than Microsoft had anticipated and, as a result, NT and Chicago would not be unified until Windows XP—albeit Windows 2000, oriented to business, had already unified most of the system’s bolts and gears, it was XP that was sold to home consumers like Windows 95 and came to be viewed as the final unified OS. Parts of Cairo have still not made it into Windows as of 2009 - specifically, the WinFS  file system, which was the much touted Object File System of Cairo. Microsoft announced that they have discontinued the separate release of WinFS for Windows XP and Windows Vista and will gradually incorporate the technologies developed for WinFS in other products and technologies, notably Microsoft SQL Server.

Driver support was lacking due to the increased programming difficulty in dealing with NT's superior hardware abstraction model. This problem plagued the NT line all the way through Windows 2000. Programmers complained that it was too hard to write drivers for NT, and hardware developers were not going to go through the trouble of developing drivers for a small segment of the market. Additionally, although allowing for good performance and fuller exploitation of system resources, it was also resource-intensive on limited hardware, and thus was only suitable for larger, more expensive machines.

However, these same features made Windows NT perfect for the LAN server market (which in 1993 was experiencing a rapid boom, as office networking was becoming common). NT also had advanced network connectivity options and the efficient NTFS file system. Windows NT version 3.51 was Microsoft's entry into this field, and took away market share from Novell (the dominant player) in the following years.

One of Microsoft's biggest advances initially developed for Windows NT was a new 32-bit API, to replace the legacy 16-bit Windows API. This API was called Win32, and from then on Microsoft referred to the older 16-bit API as Win16. The Win32 API had three main implementations: one for Windows NT, one for Win32s (which was a subset of Win32 which could be used on Windows 3.1 systems), and one for Chicago. Thus Microsoft sought to ensure some degree of compatibility between the Chicago design and Windows NT, even though the two systems had radically different internal architectures. Windows NT was the first Windows operating system based on a hybrid kernel.