History of Microsoft Windows - Windows 3.1 and NT 3.x

Windows 3.1 and NT 3.x

In response to the impending release of OS/2 2.0, Microsoft developed Windows 3.1, which included several minor improvements to Windows 3.0 (such as display of TrueType scalable fonts, developed jointly with Apple), but primarily consisted of bugfixes and multimedia support. It also excluded support for Real mode, and only ran on an 80286 or better processor. Later Microsoft also released Windows 3.11, a touch-up to Windows 3.1 which included all of the patches and updates that followed the release of Windows 3.1 in 1992. Around the same time, Microsoft released Windows for Workgroups (WfW), which was available both as an add-on for existing Windows 3.1 installations and in a version that included the base Windows environment and the networking extensions all in one package. Windows for Workgroups included improved network drivers and protocol stacks, and support for peer-to-peer networking. One optional download for WfW was the "Wolverine" TCP/IP protocol stack, which allowed for easy access to the Internet through corporate networks. There were two versions of Windows for Workgroups, WfW 3.1 and WfW 3.11. Unlike prior versions, Windows for Workgroups 3.11 ran in 386 enhanced mode only, and needs at least an 80386SX processor.

All these versions continued version 3.0's impressive sales pace. Even though the 3.1x series still lacked most of the important features of OS/2, such as long file names, a desktop, or protection of the system against misbehaving applications, Microsoft quickly took over the OS and GUI markets for the IBM PC. The Windows API became the de facto standard for consumer software.

Meanwhile, Microsoft continued to develop Windows NT. The main architect of the system was Dave Cutler, one of the chief architects of VMS at Digital Equipment Corporation (later acquired by Compaq, now part of Hewlett-Packard). Microsoft hired him in August 1988 to create a successor to OS/2, but Cutler created a completely new system instead. Cutler had been developing a follow-on to VMS at DEC called Mica, and when DEC dropped the project he brought the expertise and around 20 engineers with him to Microsoft. DEC also believed he brought Mica's code to Microsoft and sued. Microsoft eventually paid US$150 million and agreed to support DEC's Alpha CPU chip in NT.

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, codenamed 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 NTFS, an efficient 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.