Windows NT 3.1
|Windows NT 3.1|
|Part of the Microsoft Windows family|
|Screenshot of Windows NT 3.1|
|Initial release||July 26, 1993 [[ info]]|
|3.1 (Build 528: Service Pack 3) (October 29, 1994 info]]) [[|
|Source model||Closed source|
|Platform support||IA-32, Alpha, MIPS|
|Succeeded by||Windows NT 3.5 (1994)|
|Unsupported as of 31 December 2000|
Windows NT 3.1 is a 32-bit operating system developed by Microsoft. It constitutes the first operating system of the Windows NT family and was released on July 26, 1993. The version number was chosen to match the one of Windows 3.1 on account of the similar visual appearance of the user interface.
The architecture of Windows NT 3.1 was designed from scratch. The central design goals were portability to multiple processor architectures, as well as higher security and stability than the previous DOS-based operating systems. Windows NT 3.1 was released in a workstation variant, called just Windows NT 3.1, and a server variant called Windows NT 3.1 Advanced Server.
The operating system's success on the market was only limited, mostly due to the high system requirements for its time and the lack of 32-bit applications which used the capabilities of Windows NT 3.1. Nevertheless, the operating system laid the foundation for all future releases of the Windows NT line.
In the 1980s, Microsoft was a leading company in the Personal computer market due to MS-DOS, the operating system of the prevalent IBM PC compatible computers. Nathan Myhrvold, whose company was previously bought by Microsoft, noticed two dangers that would in the long run endanger the importance of MS-DOS. On the one side, new processors based on the Reduced instruction set computing principle emerged that were more powerful than the respective Intel processors which MS-DOS ran on. On the other side, a new operating system called Unix was created a decade earlier which had excellent multitasking and networking capabilities and ran on multiple processors. Because this operating system could be freely copied and modified in earlier times, several derivatives of the Unix operating systems existed. Due to them being incompatible to one another, applications had to be specifically adapted to every derivative. While this prevented Unix from becoming very widespread, Bill Gates was worried about the combination of RISC computers and Unix. He was convinced he needed a “Unix killer” and ordered Nathan Myhrvold to start development on a portable operating system.
Digital Equipment Corporation, a computer manufacturer which experienced a large growth at that time, had an experienced software developer called David N. Cutler, who was responsible for the development of the VMS operating system. In 1985, Cutler and his development team were ordered to develop a new family of computers called Prism, as well as an operating system called Mica. There were many conflicts with the employer in the development period, and in June 1988, Digital decided to cancel the project. While this did not come to a surprise for Cutler, it affected his mood. Cutler wanted to leave Digital as soon as possible, but the company convinced him to hold on. Rumors surrounding Cutler's end at Digital reached Microsoft on August 4, 1988. While Gates did not know Cutler personally, he knew about his experience and wanted to get him. Cutler agreed on the condition that he could bring part of his development team, including computer designers, along with him. While Microsoft did not manufacture computers itself, it agreed to the conditions and thus acquired Cutler as part of the company. Cutler arrived at Microsoft on October 31, 1988, and work on the future operating system started in November.
The beginning as an OS/2 project 
The new operating system was at first developed as an extended version of OS/2. OS/2 was an operating system developed jointly by Microsoft and IBM. It was originally intended to replace MS-DOS, but hadn't been successful up to that point. In the beginning of 1989, the first requirements were defined which had to be met so that NT OS/2, as the operating system was called at that time, would be successful on the market. The operating system should be portable to be able to adapt to changes in the processor market. It should also be able to use the capabilities of multiprocessor systems, which few operating systems supported at that time. The growing number of computers in companies meant that the operating system should include networking functions. Finally, the operating system was to meet requirements of the U.S. government. These included support of the POSIX standard, and a level of security, based on the Trusted Computer System Evaluation Criteria. The goal for NT was to meet the requirements of level C2; this required separate user account, a permission system and the ability to audit security-related events.
As a first step towards portability, it was decided to develop the operating system on non-x86-systems at first to prevent unintended usage of x86 specific code, which would've hindered the porting of the operating system. At first, the Intel i860 processor was chosen; because Microsoft didn't have this processor, development started on an emulator. The codename of the Intel i860 processor, N-Ten, was the origin of the name of the operating system NT, only later the name was redefined as an abbreviation of New Technology for marketing purposes. Digital assumed that source code of the Mica project would be reused for the new operating system and so decided to sue Microsoft. The two companies settled out of court, and Microsoft agreed to support Digital's Alpha processor. In April 1989 the operating system's kernel ran inside the emulator, and the developer team assumed the operating system would be finished in 18 months. The Intel i860 processor, however, turned out to be unsuitable, so development switched to a MIPS R3000 processor in December. Within three months, the entire operating system was ported to the new processor.
In February 1990, Microsoft employee Paul Maritz suggested to present NT at the upcoming COMDEX in fall 1990. This would serve as a response to competitors, who claimed that the operating system would not be ready until 1994, while Maritz claimed development would be finished in 1992.
Continuation as Windows NT 
In May 1990, Microsoft published the Windows 3.0 operating system which turned out to be a huge success. This hurt the relationship between Microsoft and IBM because IBM wanted Microsoft to concentrate on development of OS/2 rather than bothering with its Windows operating system. At that time, Microsoft employed 150 programmers for the development of OS/2 and paid a total of $50 million, resources which were in turn not available for other projects like NT. The parallel work on multiple completely different operating systems did not only waste resources, but was a big problem for marketing as well. Software developers had a hard time deciding between developing their software for Windows or OS/2 since both systems were incompatible to one another and it was not yet certain which of the two operating systems would make the breakthrough in the end.
These reasons caused Microsoft to decide in August 1990 to develop their operating system as “Windows NT”. The OS/2 API would no longer be part of the future operating system, but only be available separately. It was instead decided to reuse most of the functions of the Win16 API and extend it with new functions to make it easy for programmers who were already used to Win16 development to make the switch to Windows NT. NT was originally planned to include the Presentation Manager graphical shell of OS/2, which now had to be replaced with the Windows shell. These changes made it impossible to demonstrate the operating system on COMDEX 1990.
The public did not know of these developments yet, and even the partner IBM had no idea of the ongoing split-up. Instead, Microsoft and IBM decided to readjust their partnership; IBM would be solely responsible for the next version of OS/2, version 2.0, while Microsoft would develop the subsequent version 3.0. In January 1991, at an internal meeting with IBM employees, the company realized Microsoft's actual plans and the alliance broke for once and for all. This was reported to the press on July 1991.
In September 1991, Windows NT was prepared for a demonstration at this year's COMDEX scheduled for next month. The goal of this first public demonstration was to get software developers to switch to the new operating system, because it was realized that without applications designed for Windows NT, the operating system would not be able to put its capabilities to full use. At COMDEX, the multiprocessing capabilities of the operating system were demonstrated and 32-bit development kits were handed out to selected developers. The target for the release of the operating system was set to the end of 1992. The responses to the demonstration were astonishing, 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.
To get more developers to switch to the new operating system, a new interface called Win32s was announced in March 1992 which allowed Windows NT applications to run on Windows 3.1, with the intended goal that these applications would already be usable before Windows NT was released. On a conference held in San Francisco from June 6 through June 8, 1992, Windows NT was shown running on x86 as well as MIPS computers. CDs with a pre-release version of Windows NT, including a new version of the development kit, were distributed. This development kit included a program that helped migrate 16-bit Windows applications to Windows NT. Microsoft also announced a 32-bit version of Microsoft SQL Server that would run on Windows NT. As a response, Unix vendors feared that their operating system would lose market share to Windows NT.
The high memory usage of the operating system turned out to be a problem, after a test PC Week deemed Windows NT to be unusable. Most PCs of that time shipped with 4 megabytes of memory, but the developers thought that 16 megabytes were necessary to run Windows NT. Due to the high costs for memory, they feared that Windows NT would not sell well due to its memory usage. The developers tried reducing the memory usage of the operating system using various methods, including paging of the operating system core.
As it became clear that Windows NT would not be released until 1993, analysts saw this as an advantage for competitor IBM, whose operating system OS/2 2.0 was already released. In October 1992, public beta testing of the operating system began and Microsoft sent 20,000 copies of a pre-release version to beta testers to detect programming bugs. The company used the COMDEX in November 1992 to demonstrate various third-party software for Windows NT.
In March 1993, the last public pre-release version was shipped to 70,000 people. At the same time, the first details of the server variant Windows NT Advanced Server, which was previously only known as Windows NT with LAN Manager, were published. While this pre-release version turned out to be much more stable and faster compared to the last one, there were still a lot of bugs present, and user feared that the operating system would either be released in an unfinished state, or delayed well until the end of 1993. The last public presentation of Windows NT was at the COMDEX in May 1993. Because the operating system was repositioned to the high-end market, software manufacturers were unsure if the new operating system would become widespread as a client and hesitated with porting their software to the 32-bit architecture.
Windows NT 3.1 and Windows NT 3.1 Advanced Server were released on July 26, 1993. At first, only the x86 and MIPS versions shipped, the Alpha version followed in September. The version number 3.1 was chosen on purpose to be on par with the 16-bit operating system Windows 3.1. The workstation version cost $495; the server version was planned to be sold for $2,995 and be available in the first six months only for $1,495, but in the end this discount was kept until the release of the successor. 250 programmers wrote 5.6 million lines of code, the development cost $150 million. In the last year of development, over 30,000 programming bugs were fixed.
To fix errors in the operating system, three service packs were published subsequently: Service Pack 1 was released on October 8, 1993, Service Pack 2 followed on January 24, 1994 and Service Pack 3's release came on October 29, 1994. The Service Packs were rolled not only on CD and floppies, but also via bulletin board systems, CompuServe and the then-new Internet. Support for the operating system ended on December 31, 2000.
Windows NT 3.1 was localized into various languages, besides English, it was available in Dutch, French, German, Japanese, Spanish and Swedish. Only the workstation, but not the server was available in Danish, Finnish, Italian, Norwegian and Portuguese.
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. To meet this goal, most of the operating systems, including the operating system core, had to be written in the C programming language. During the planning phase it was clear that this would cause Windows NT to have a higher memory consumption than all previous operating systems. Besides the graphics system and parts of the networking system, which were written in C++, only parts of the operating systems which required direct hardware access and performance critical functions were written in assembly language. These parts were isolated so that they could easily be rewritten when porting the operating system to a new architecture.
The second goal was reliability: The system should no longer crash due to a faulty application or faulty hardware. This way, the operating system should be made attractive for critical applications. To meet this goal, the architecture of Windows NT was designed so that the operating system core was isolated and applications could not access it directly. The kernel was designed as a microkernel and components of the core were to run atop the kernel in a modular fashion; Cutler knew this principle from his work at Digital. Reliability also includes security, and the operating system should be able to resist external attacks. Mainframes already had a system where every user had their own account which was assigned specific rights by the administrator, this way, users could be prevented access to confidential documents. A virtual memory management was designed to thwart attacks by malware and prevent users from accessing foreign areas of memory.
The third goal was called personality: The operating system should be able to run applications designed for various operating systems, such as Windows, MS-DOS and OS/2 applications. The Mach kernel followed a similar concept by moving the APIs to components which operated in user mode as applications, these could be changed and new ones could be added. This principle was applied to Windows NT.
Despite all these goals, the performance of the operating system was optimized where possible, by adapting critical sections of the code to fast execution speed. To improve networking performance, large parts of the networking system were moved to the operating system core.
Windows NT was designed as a networking operating system. In this branch, Novell had a lead with its product NetWare, mostly because of a lack of competition, and Microsoft failed to develop a product which could challenge NetWare's lead. Cutler hoped to gain additional customers with a reliable networking operating system. Bill Gates already dominated the market of desktop operating systems with MS-DOS and Windows and hoped to do the same in the networking market with Windows NT. He especially hoped to find a market in the emerging amount of servers, while at the same time he did not expect a success in the desktop market until 1995.
Therefore, Windows NT was positioned as a high-end operating system in an interview with the product manager Paul Thacher. It was not designed to replace Windows 3.1 completely, but it should rather supplement Microsoft's product palette with an operating system for critical applications. The expectations were 10% to 20% among all Windows sales and a market share of 10% in the high end market, which amounted to one million copies.
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 architecture of Windows NT takes some ideas of the client-server model, like the modular structure and the communication between the modules. System resources like memory, files or devices are viewed as objects by the operating system, which are all accessed in the same way through handles and which can in this way be secured against unauthorized access.
The operating system was designed for multiprocessor systems; it supports preemptive multitasking and can make use of threads to run multiple processes in parallel. Using symmetric multiprocessing, the processing usage is evenly distributed among all available processors. The inter-process communication in Windows NT 3.1 is designed around networks; two newly introduced functions, Remote Procedure Call (RPC) and Network DDE, an extension of Dynamic Data Exchange (DDE), facilitate the access and data exchange between processes running on different computers inside a network.
The operating system is designed to combine certain elements of a monolithic kernel and a microkernel; nowadays this is most often referred to as a hybrid kernel. 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. The kernel running atop only has very basic functions like interrupt management and processor synchronization. All other functions of the operating system core are handled by modules which operate independently from one another and can be swapped without affecting the rest of the operating system.
Positioned above the operating system core are the subsystems. There are two types of subsystems: one are the integral subsystems, which perform important operating system functions. One such subsystem is the security subsystem, which handles the logon process and monitors the security of the system. The other type of subsystem is the environment subsystem, which exposes the operating system functions to applications via application programming interfaces. The base subsystem is the 32-bit subsystem which runs 32-bit applications written for Windows NT. Windows NT applications can only run on one platform, and must be recompiled for every platform. The 32-bit subsystem also contains all output functions, including the Graphics Device Interface (GDI), so all other subsystems have to call the 32-bit subsystem to be able to output text or graphics. Other subsystems contained in Windows NT 3.1 are the POSIX subsystem, which supports POSIX-compatible applications built for Windows NT, and, in the x86 version only, the OS/2 subsystem, which allows command-line based OS/2 1.x applications to run.
The Virtual DOS Machine (VDM) is sometimes also viewed as a subsystem, but is, strictly speaking, a normal 32-bit Windows application. It manages applications originally built for DOS. Built on top is Windows on Windows (WoW), which allows applications built for 16-bit Windows operating systems like Windows 3.1 to run. On x86 computers, the virtual DOS machine uses the virtual 8086 mode to run DOS applications directly, on RISC computers, an emulator licensed from Insignia Solutions is used which emulates a 80286 processor. However, not all DOS and 16-bit Windows applications can be run on Windows NT 3.1 due to various limitations, 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.
System description 
Windows NT 3.1 provides a boot manager called NTLDR which is loaded during the startup process of the operating system on x86-based computers. It allows a multiboot setup of multiple instances of Windows NT 3.1, as well as MS-DOS and OS/2 1.x. 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.
Windows NT 3.1 introduced the new NTFS file system. This new file system is more robust against hardware failures and allows assignment of read and write rights to users or groups on the file system level. NTFS supports long file names and has features to accommodate POSIX applications like hard links. For compatibility reasons, Windows NT 3.1 also supports FAT16 as well as OS/2's file system HPFS.
Designed as a networking operating system, Windows NT 3.1 supports multiple network protocols. Besides IPX/SPX and NetBEUI, the TCP/IP protocol is supported allowing access to the Internet. Similar to Windows for Workgroups, files and printers can be shared and the access rights and configuration of these resources can be edited over the network. When a network printer is installed, the required drivers are automatically transferred over the network, removing the need to manually install the drivers for every computer. The Remote Access Service (RAS) allows a client from outside the network to connect to the network using a modem, ISDN or X.25 and access its resources. While the workstation allows one RAS connection at a time, the server supports 64.
Windows NT 3.1 supports the then-new Unicode standard, a character set which allows multiple languages to be displayed. This facilitates localization of the operating system. All strings, as well as file and folder names, are internally processed in Unicode, but the included programs, like the File Manager, are not Unicode aware, so folders containing Unicode characters cannot be accessed. 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.
The Windows registry, introduced with Windows NT 3.1, is a central, hierarchical configuration database designed to allow configuration of computers over the network and to replace the commonly-used text-based configuration files, like INI files, AUTOEXEC.BAT and CONFIG.SYS. Using the undocumented registry editor, the Windows registry can be viewed and edited by the user.
The Advanced Server is designed to manage the workstation computers. It can function as a Domain controller, where all users and groups as well as their rights are stored. This way, a user can log on from any computer in the network, and users can be managed centrally on the server. Trust relationships can be built to other domains to be able to exchange data cross-domain. Using the replication service, files like logon scripts can be synchronized across all computers on the network. The Advanced Server supports the AppleTalk protocol to allow connections to Macintosh computers. Hard drives can be combined to RAIDs in Windows NT 3.1 Advanced Server, the supported configurations are RAID 0, RAID 1 and RAID 5.
Included programs 
Windows NT 3.1, for the most part, comes with 32-bit versions of the components featured in Windows 3.1 and Windows for Workgroups. However, it also included applications specifically aimed at the needs of Windows NT, like the User Manager, the Performance Monitor, the Disk Administrator, the Event Viewer and the Backup application. The Advanced Server contained further, server-specific administration tools. Because Windows NT 3.1 is not DOS-based, a new 32-bit command-line processor, called CMD.EXE was included which was compatible with MS-DOS 5.0. For compatibility reasons, Windows NT 3.1 shipped with a few 16-bit applications, like Microsoft Write or EDLIN.
Windows NT 3.1, being an all-new operating system for which no previous drivers could be used, includes a wealth of drivers for various common components and peripherals. This includes common SCSI devices like hard drives, CD-ROM drives, tape drives and image scanners, as well as ISA devices like graphics cards, sound cards and network cards. The PCI bus, however, is expressly not supported. Windows NT 3.1 supports an uninterruptible power supply.
Windows NT 3.1 could be installed either by using the CD-ROM and a provided boot disk, or by utilizing a set of 22 3.5" floppies (23 floppies for Advanced Server). Windows NT 3.1 could also be installed over the network. A coupon was included that made it possible to order a set of 27 5.25" floppies (or 28 floppies for Advanced Server). Compared to the floppies, the CD-ROM contained additional drivers and applications.
System requirements 
Windows NT 3.1 supports multiple platforms: Besides the x86 architecture, it can be run on computers with MIPS R4000 and R4400 processors, as well a computers with an Alpha processor.
The minimum system requirements for the installation on x86-based systems is 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 and 92 megabytes of hard drive spaces and need a CD-ROM drive. For the Advanced Server, the requirements is an 80386 processor with 16 megabytes of memory and 90 megabytes of hard drive space, or in the case of a RISC system 110 megabytes of hard drive space. Windows NT 3.1 supports multiprocessor systems with up to two processors, the Advanced Server 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. This problem was never fixed by Microsoft, but unofficial patches are available which allow the operating system to be installed.
Public reception 
Windows NT 3.1 sold about 300,000 copies in its first year. 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, and the operating system turned out to be too slow to use. 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 software, like an office suite, was not available at all for Windows NT 3.1. During the development of the operating system, the API calls were changed so 32-bit applications built on the pre-release version of Windows NT 3.1 could not be run on the final version. This affected even commercial software like Microsoft Visual C++.
RISC systems with Windows NT 3.1 had an even bigger disadvantage: even though they were more powerful than x86 systems, almost no 32-bit applications or drivers were ported to these platforms. 16-bit applications ran much slower under RISC systems because of the 80286 emulation compared to x86 systems which could run 16-bit applications natively, and DOS and 16-bit applications which depended on 386 calls could not be run at all on RISC systems.
However, not all reception was negative; the multitasking capabilities of the operating system were rated positively, especially compared to Windows 3.1. Compared to the size of the operating system, the installation turned out to be very easy, even though installing from floppies was a very time-consuming task. 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 amount of clients, unlike its competitor Novell NetWare.
With Windows NT, Microsoft entered a market it could not previously address and which was mostly dominated by Unix, Novell NetWare and OS/2. 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. Manufacturers of microprocessors hoped to use the portability of the new operating system to increase their own sales, and thus ports of Windows NT were announced for various platforms, like the Sun SPARC architecture 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.
Further reading 
- Zachary, G. Pascal (2009). SHOWSTOPPER!. New York: E-Rights/E-Reads. ISBN 0-7592-8578-0. Unknown parameter
- Custer, Helen (1993). Inside Windows NT. Redmond: Microsoft Press. ISBN 1-55615-481-X.
- Zachary 2009, p. 300
- "moderator" (1994-11-07). "61 New Uploads to CICA [11/07/94]". comp.os.ms-windows.announce.
- "Microsoft Support Lifecycle - Windows NT Workstation 3.1". Retrieved 2012-06-08.
- "Microsoft Support Lifecycle - Windows NT Advanced Server 3.1". Retrieved 2012-10-06.
- Zachary 2009, p. 31
- Custer 1993, pp. 34–35
- Zachary 2009, p. 35
- Zachary 2009, p. 17
- Zachary 2009, p. 24
- Zachary 2009, p. 25
- Zachary 2009, p. 36
- Zachary 2009, p. 37
- Zachary 2009, p. 38
- Smith, Mark (1999-08-27). "The Death of Alpha on NT". Retrieved 2012-05-19.
- Custer 1993, pp. 43–44
- Zachary 2009, p. 33
- "National Museum of American History | Microsoft Windows NT OS/2 Design Workbook". Retrieved 2012-06-09.
- Custer 1993, p. 2
- Custer 1993, p. 3
- "Department of Defense - Trusted Computer System Evaluation Criteria" (PDF; 0,4 MB). Retrieved 2012-09-19.
- Thurrott, Paul (2003-01-24). "Windows Server 2003: The Road To Gold - Part One: The Early Years". Archived from the original on 2005-01-01. Retrieved 2012-05-28.
- Custer 1993, pp. 84–85
- Custer 1993, pp. 98–99
- Zachary 2009, p. 100
- Custer 1993, pp. 99–100
- Glass, Brett (1991-05-27). "Windows, OS/2 debate is still a hot topic: Software vendors with limited resources are still forced to choose between Windows and OS/2 development". InfoWorld 13 (21): 66.
- Zachary 2009, p. 102
- Johnston, Stuart J. (1991-07-08). "Microsoft drops OS/2 2.0 API, revamps 32-bit Windows plan: Users face choice between OS/2 and Windows NT". InfoWorld 13 (27): 1, 103.
- Zachary 2009, p. 105
- Zachary 2009, p. 54
- Zachary 2009, p. 101
- Zachary 2009, p. 108
- Parker, Rachel (1990-12-24). "Two giants with own views: IBM needs OS/2; Microsoft does Windows". InfoWorld 12 (52): 8.
- Custer 1993, pp. 108–109
- Zachary 2009, p. 165
- Johnston, Stuart J. (1991-10-28). "NT looks real at Comdex: Microsoft declares it will start beta tests in early 1992". InfoWorld 13 (43): 1, 8.
- Custer 1993, pp. 175–176
- Machrone, Bill (1991-11-26). "Are NT Promises MT Promises?". PC Magazine 10 (20): 85f. ISSN 0888-8507.
- Johnston, Stuart J. (1992-03-02). "Microsoft reveals 32-bit strategy: Win32s lets NT applications run on Windows 3.1". InfoWorld 14 (9): 1, 107.
- Siering, Peter (1992). "Betriebssystem-Poker: Erste Blicke auf Windows NT". c't (9): 42 ff.
- Strehlo, Kevin (1992-07-13). "Microsoft makes its move with Windows NT SDK". InfoWorld 14 (28): 1, 92.
- Johnston, Stuart J. (1992-07-20). "SDK readied for SQL Server for NT: Will speed writing of 32-bit code". InfoWorld 14 (29): 8.
- Hammett, Jim; Vance McCarthy (1992-12-14). "Unix vendors strike out at Microsoft: Campaign seeks to steal thunder of Windows NT". InfoWorld 14 (50): 8.
- Zachary 2009, p. 227
- Zachary 2009, p. 229
- Zachary 2009, p. 230
- Custer 1993, pp. 248–249
- Willett, Shawn (1992-10-12). "NT's delays mean a second look and respect for OS/2". InfoWorld 14 (41): 17.
- Johnston, Stuart J. (1992-10-26). "Microsoft rolls out Windows NT beta". InfoWorld 14 (43): 3.
- Johnston, Stuart J. (1992-11-23). "Vendors throw support behind Windows NT". InfoWorld 14 (47): 3.
- Johnston, Stuart J. (1993-03-22). "Microsoft ships final Windows NT beta". InfoWorld 15 (12): 3.
- Johnston, Stuart J. (1993-03-15). "NT server edition to get remote access". InfoWorld 15 (11): 1, 107.
- Johnston, Stuart J. (1993-04-05). "NT is shaping up, say latest beta users: But they want a bug-free final version, even if it's late". InfoWorld 15 (14): 3.
- Willett, Shawn; Jeanette Borzo (1993-05-31). "Users praise NT's graphics support at Comdex". InfoWorld 15 (22): 13.
- Johnston, Stuart J.; Doug Barney (1993-09-20). "NT version for Alpha chip poised to ship to users". InfoWorld 15 (38): 3.
- Mace, Scott (1993-05-31). "NT keeps client/server apps waiting: Database servers will be ready as soon as Microsoft ships delayed OS". InfoWorld 15 (22): 1.
- Barney, Doug (1994-09-19). "Microsoft set to ship Windows NT 3.5: Will bolster push into enterprise with SMS release". InfoWorld 16 (38): 5.
- Hixson, Amanda (1993-05-24). "Aiming for the high end: An Interview with Paul Thatcher, Microsoft’s Windows NT product manager". InfoWorld 15 (21): 92.
- Zachary 2009, p. 290
- Zachary 2009, p. 307
- Dave Macdonald (1993-10-08). "First update for Windows NT 3.1 is available!". comp.os.ms-windows.announce.
- Steve Heaney (1994-01-24). "US Service Pack 2 Now Available". comp.os.ms-windows.nt.setup.
- Microsoft Knowledge Base - README.TXT: U.S. Service Pack for Windows NT (no longer available online)
- Microsoft Knowledge Base - How To Obtain U.S. Service Pack for Windows NT (no longer available online, the Knowledge Base number 104597 now refers to a different article)
- "Microsoft - List of Localized MS Operating Systems - Older Versions of Windows". Retrieved 2012-06-04.
- Zachary 2009, p. 53
- Russinovich, Mark (1998-12-01). "Windows NT and VMS: The Rest of the Story". Retrieved 2012-05-19.
- Zachary 2009, p. 55
- Custer 1993, pp. 8–9
- Custer 1993, p. 9
- Zachary 2009, p. 56
- Zachary 2009, p. 57
- Custer 1993, pp. 157–158
- Custer 1993, p. 10
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- Custer 1993, p. 12
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