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. 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.

Development history

The origins of Windows NT date back to 1988, where Microsoft had a major foothold on the personal computer market due to the use of its MS-DOS as the operating system of IBM PC compatibles. Nathan Myhrvold, who had joined Microsoft after its acquisition of Dynamical Systems Research, identified two major threats to Microsoft's monopoly—RISC architectures, which proved to be more powerful than the equivalent Intel processors that MS-DOS ran on, and Unix, a family of cross-platform multitasking operating systems with support for multiprocessing and networking. Myhrvold wanted to develop a new system that would run on RISC workstations and Intel chips and multiprocessing computers.

The operating system was first developed as a revised version of OS/2, an operating system Microsoft had jointly developed with IBM. To target the enterprise market, the OS was also to support networking, the POSIX standard, and a security platform compliant with the "Orange Book" standards; which would require the OS to be a multi-user system with a permission framework and the ability to audit security-related events.

Both Microsoft and IBM wanted to market an operating system that appealed to corporate "enterprise software" customers. That meant greater security, reliability, processing power, and computer networking features. However, since Microsoft also wanted to capture market share from Unix on other computing platforms, they needed a system design that was more portable than that of OS/2.

To this end, Microsoft began by developing and testing their new operating system for a non-x86 processor: an emulated version of the Intel i860. Alluding to the chip's codename, "N10", Microsoft codenamed their operating system NT OS/2. DEC preemptively sued Microsoft, alleging that they stole code from MICA for use in the new operating system. In an out-of-court settlement, Microsoft agreed to make NT OS/2 compatible with DEC's Alpha processor. In August 1990, as a response to the popularity of Windows 3.0, the NT OS/2 team decided to re-work the operating system to use an extended 32-bit port of the Windows API known as Win32. Win32 maintained the familiar structure of the 16-bit APIs used by Windows, which would allow developers to easily adapt their software for the new platform while maintaining a level of compatibility with existing software for Windows. With the shift to a Windows-like architecture, the operating system's shell was also changed from OS/2's Presentation Manager to Windows' Program Manager. IBM eventually learned of Microsoft's Windows NT plans in January 1991, and immediately ended the OS/2 partnership. IBM would solely develop OS/2 2.0 (as was planned under the amended version) and all future versions, without any further involvement from Microsoft. The demonstration was positively received; PC Magazine called Windows NT "the modern reinvention of the operating system", but at the same time claimed that it was unlikely that the promised backward compatibility would be kept for the final release. In March 1992, Microsoft also released Win32s, which would allow Windows 3.1 to have partial compatibility with Windows NT programs for the purposes of developing software optimized for the platform.

At Microsoft's Win32 Professional Developers Conference in June 1992, Windows NT was demonstrated running on x86 and MIPS processors, while a beta version of Windows NT and an updated development kit were also made available. Concurrently, Microsoft announced a new version of its SQL Server product for Windows NT; Unix vendors feared that the software could be a killer app that would affect the market share of Unix systems. Concerns were also raised over NT's memory usage; while most computers of the era shipped with 4 megabytes of RAM, 16 MB was recommended for NTs. Due to the high cost of RAM at the time, critics thought that its high system requirements could affect the sales and adoption of Windows NT. Steps were taken to reduce its memory usage through methods such as paging. The final pre-release version of NT was released in March 1993, alongside the unveiling of the server version, LAN Manager for Windows NT. Although its stability and performance had improved, there were still fears that the OS could be released in an unfinished state or delayed further into 1993.

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 yet re-engineered.

Release

Windows NT 3.1 and Windows NT 3.1 Advanced Server (so numbered to associate them with Windows 3.1) were released on July 26, 1993. Microsoft sold the workstation version for , and the server version for . Ostensibly, the server price was meant to be a promotional discount offered only during the first six months of sale, but they never raised the retail price to the listed one—. 250 programmers wrote 5.6 million lines of code;

Operating system goals

Cutler set three main goals for Windows NT. The first goal was portability: in contrast to previous operating systems, which were strongly tied to one architecture, Windows NT should be able to operate on multiple architectures. During the planning phase it was clear that this would cause Windows NT to have higher memory consumption than all previous operating systems.

Features

Architecture

While Windows NT 3.1 uses the same graphical user interface as Windows 3.1, it was developed anew. The operating system is not DOS-based, but an independent 32-bit operating system; many concepts were taken from Cutler's previous operating system, VMS.

The operating system is designed to combine certain elements of a monolithic kernel and a microkernel; The hardware abstraction layer represents the lowermost layer and isolates the operating system from the underlying hardware to make it easy to port the operating system to other platforms. so all other subsystems have to call the 32-bit subsystem to be able to output text or graphics. one of them being the inability of applications to directly access the hardware. As well, VxD files sometimes needed by applications cannot be used with Windows NT 3.1. While pure DOS applications are run in separate memory spaces, 16-bit Windows applications have to share one memory space. While this is done due to compatibility reasons with applications which depend on this ability, like Schedule+ and Microsoft Mail, it also means that 16-bit Windows applications only run in cooperative multitasking. A faulty 16-bit Windows application is in this way able to cause all other 16-bit Windows applications (but not Windows NT itself) to crash. NTLDR is not used for the RISC versions because the RISC computers' firmware provides their own boot manager.

Every user has to log on to the computer after Windows NT 3.1 is booted up by pressing the key combination Ctrl+Alt+Del and entering the user name and password. All users have their own user account, and user-specific settings like the Program Manager groups are stored separately for every user. Users can be assigned specific rights, like the right to change the system time or the right to shut down the computer. To facilitate management of user accounts, it is also possible to group multiple user accounts and assign rights to groups of users. All strings, as well as file and folder names, are internally processed in Unicode, For demonstration purposes, a Unicode typeface called Lucida Sans Unicode is shipped with Windows NT 3.1 even though it is not installed by default. The previous code pages are still supported for compatibility purposes.

Windows NT 3.1, being an all-new operating system for which no previous MS-DOS based drivers could be used, includes a wealth of drivers for various common components and peripherals. as well as ISA devices like graphics cards, sound cards and network cards. The EISA bus is supported by Windows NT 3.1. The PCI bus, however, is not supported by kernel, but supported by third-party drivers. Windows NT 3.1 supports an uninterruptible power supply. Compared to the floppies, the CD-ROM contained additional drivers and applications.

Windows NT 3.1 does not support ATAPI CD-ROMs.

System requirements

Windows NT 3.1 supports multiple platforms: Aside from the x86 architecture, it runs on computers with DEC Alpha or MIPS (R4000 and R4400) processors.

Minimum system requirements on x86 systems include a 25 MHz 80386 processor, at least 12 megabytes of memory, 75 megabytes of hard drive space, and a VGA graphics card. RISC systems require 16 megabytes of memory, 92 megabytes of hard drive space, and a CD-ROM drive. The Advanced Server edition requires an 80386 processor with 16 megabytes of memory and 90 megabytes of hard drive space. On RISC systems, 110 megabytes of hard drive space is needed.

Windows NT 3.1 supports dual processor systems, while the Advanced Server edition supports up to four processors. Due to an error in the processor detection routine, Windows NT 3.1 cannot be installed on Pentium II or newer processors. Microsoft never fixed the problem, but unofficial patches are available. The hardware requirements were deemed to be very high at that time; the recommended system requirements of a 486 processor with 16 megabytes of memory were well above the average computer's configuration, 32-bit applications which could have used the capabilities of Windows NT 3.1 were scarce, so users had to resort to the old 16-bit applications; however, these ran slower than on Windows 3.1. Estimates in November 1993 counted only 150 Windows NT applications. Common types of software, like office suites, were not available for Windows NT 3.1.

RISC systems with Windows NT 3.1 had an even bigger disadvantage: even though they were more powerful than x86 systems, The Advanced Server, intended to be the successor to the unsuccessful LAN Manager product, was technically much superior to its predecessor, and only failed to gain success because it shared the same problems with its workstation pendant, such as the low performance running 16-bit applications. The Advanced Server provided a financial advantage for large networks because its price was not dependent on the number of clients, unlike its competitor Novell NetWare. A test performed by the InfoWorld magazine in November 1993, where the networking capabilities of several operating systems were tested, showed that Windows NT 3.1 was seriously lacking in inter-client communication: it could only connect to its own server via NetBEUI; attempts to connect to Unix, NetWare and OS/2 all failed because no client software was available. For the Advanced Server, only their own client, the Macintosh and, if only limited, OS/2 were able to connect to the server.

Even though the operating system's actual success was only moderate, it had a huge lasting impact. Developers of Unix derivations for the first time strived to standardize their operating systems, and Novell was so concerned about its market share that it bought a Unix vendor. and the Clipper architecture. It was recognized that Windows NT would dominate the desktop market as soon as the hardware became powerful enough to run the operating system at an acceptable speed. Eight years later, Microsoft would unify the consumer-oriented Windows line (which had remained MS-DOS based) with the NT line with the October 2001 release of Windows XP—the first consumer-oriented version of Windows to use the NT architecture.

Support lifecycle

References

  • Guidebook: Windows NT 3.1 Gallery – Gallery of UI screenshots of Windows NT 3.1