Microsoft Windows NT 3.5

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Windows NT 3.5
Windows NT 3.1 Logo.png
German Windows NT 3.5 with the file manager open
developer Microsoft
License (s) Microsoft EULA ( Closed Source )
First publ. September 13, 1994
Current  version 3.50.807 (Service Pack 3) (August 29, 1995)
ancestry \ Windows NT
Architecture (s) x86 , MIPS , Alpha AXP

Windows NT 3.5 is an operating system from Microsoft and the successor to version Windows NT 3.1 .


Towards the end of the development of the predecessor Microsoft Windows NT 3.1 , the developers were collecting ideas that could no longer be implemented at this stage of the development cycle and were therefore planned for the next version, which was to be published in autumn 1994.

David N. Cutler knew that the first version of a product is never perfect. Spurred on by the numerous criticisms of Windows NT 3.1, he wanted to start developing the successor immediately. However, this meant he was in competition with Cairo , a new Microsoft project led by Jim Allchin . Windows NT and the development team were to be integrated into the Cairo project and so continue development under new leadership. Cutler did not accept this decision and left the development team. Bill Gates feared Cutler would leave the company completely and tried to get him to stay. Cutler finally accepted this by developing both projects together and viewing the new leadership as a formality.

The development team set three broad goals for the new operating system. The first goal was performance because Windows NT 3.1 was widely considered to be too slow. The very high hardware requirements of the predecessor were to be reduced and the performance of the operating system optimized, which was mainly achieved through the use of improved compilers . In June 1994 Microsoft reported a four to eight megabyte lower memory consumption compared to its predecessor as well as 50 to 100 percent faster graphics display and 20 to 30 percent faster file access.

The second goal was NetWare compatibility. Novell promised a NetWare client for Windows NT, but repeatedly delayed delivery. So Microsoft finally decided to develop its own NetWare client and deliver it with Windows NT 3.5. The development team knew that Windows NT would not stand a chance on the market if it did not offer a connection to NetWare networks.

The third goal was compression. With the growing need for hard disk space, programs like DoubleSpace have become widespread under MS-DOS . Windows NT 3.5 should support a similar technology.

The developers also turned their attention to the TCP / IP protocol stack. The protocol stack included with Windows NT 3.1 was licensed from a third party called Spider Systems . Its code was based on the STREAMS programming interface used in Unix . This meant that STREAMS had to be ported to Windows NT, which had a negative effect on performance. Windows NT 3.5 should therefore contain a new, specially developed TCP / IP protocol stack.

The first information about a successor to Windows NT 3.1 with the code name Daytona came out in December 1993. In February 1994 the development was officially announced at the WinHEC . The first public presentation of the new operating system followed at the end of March.

The final version, NT 3.5, was released on September 13, 1994. On January 13, 1995, the first service pack came out, which among other things offered a method for bypassing the Pentium FDIV bug . Service Pack 2 followed on March 1, 1995. On August 29, 1995, Service Pack 3 was finally completed.


In contrast to NT 3.1, the two versions were renamed and are now called Windows NT 3.5 Workstation and Windows NT 3.5 Server . While there were hardly any differences between the workstation variant and the server in Windows NT 3.1, the two versions of Windows NT 3.5 are clearly separated from each other. Windows NT 3.5 Workstation only accepts 10 client connections, so that it cannot be used as a server apart from small networks.

Windows NT 3.5 Workstation was available for $ 319. With Windows NT 3.5 Server , Microsoft's licensing model, which is still valid today, was introduced, in which a license has to be purchased for each client that accesses the server. While the previous version of the server still cost a flat rate of USD 1,495, regardless of how many clients were connected, the price was now USD 699, with USD 39 being paid for each client.

Windows NT 3.5 Server was not only sold individually, but also under the name Microsoft BackOffice for the first time together with numerous programs such as a mail server and a Microsoft SQL server .


Compared to the predecessor, numerous detail improvements have been made. For example, 16-bit Windows programs can run in separate environments to enable preemptive multitasking between them and to prevent a faulty 16-bit application from crashing all other 16-bit applications. There is also the new option to block a user account for a certain time if the password has been entered incorrectly too often.

In Windows NT 3.5, the old Windows Setup program is no longer used to set the screen resolution and color depth , but the new Control Panel option Display . This allows the selected options to be tested in advance by displaying a test image , provided the graphics card driver supports this. To further support the development of graphics software, an OpenGL graphics library licensed by Silicon Graphics has been added to Windows NT 3.5 . The operating system came with some screensavers for demonstration purposes .

The newly developed VFAT now also enabled long file names on FAT partitions, which were limited to the 8.3 format under the previous NT 3.1 . Because of these changes and other changes to the NTFS file system, if Windows NT 3.1 and Windows NT 3.5 are to be operated in parallel on one computer, an update package must be installed from the Windows NT 3.5 CD in order to give Windows NT 3.1 access to these partitions enable.

Windows NT 3.5 includes a redesigned TCP / IP - protocol stack that has been programmed from scratch. Windows NT 3.5 supports DHCP and includes a name resolution service called WINS . A supplied NetWare client enables access to NetWare networks with on-board resources for the first time, without the need to install additional software. The Remote Access Service , which under Windows NT 3.1 only enabled access to NetBEUI resources, now also supports TCP / IP and IPX, so that NetWare shares can also be accessed. In this context, RAS supports connection establishment via PPP and SLIP .

The server version of Windows NT 3.5 contains several innovations. It offers the possibility of acting as a NetWare gateway . This allows DOS and Windows clients to access resources on a NetWare server without having to communicate directly with this network. A program should help to migrate a NetWare server and its data such as directories and users to Windows NT Server. Other computers in the network can be started remotely via the server, which is primarily intended for diskless workstations . The RAS server no longer supports 64, but 256 incoming RAS connections.

The driver library has been significantly expanded compared to its predecessor, so the PCI bus is now supported as well as modern ATAPI CD-ROM drives.

System requirements

The system requirements have not changed compared to the predecessor Windows NT 3.1. Installation on x86 systems required an 80386 processor with 25 MHz, at least 12 MB RAM, 75 MB hard disk space and a VGA graphics card . RISC systems instead required 16 MB of RAM and 92 MB of hard disk space, as well as a CD-ROM drive. In contrast to its predecessor, Windows NT 3.5 cannot be installed on 80386-based multiprocessor systems.

Windows NT can be installed either from the CD-ROM, which is supplied with three start-up disks, or from a set of disks (consisting of 21 3.5 "disks) on x86 computers. It is also possible to add an existing Windows NT 3.1 To update.

Due to an error in the processor detection, the installation of the operating system fails on all processors since the Pentium II . Microsoft has never corrected this problem, however unofficial patches are available to enable installation.


Microsoft's reports that Windows NT 3.5 was faster than its predecessor were confirmed: the same benchmarks ran faster under NT 3.5 than under NT 3.1, with an increase in performance of up to 100 percent being measured. The operating system sold better than its predecessor, which, according to analysts, was not only due to the improvements in the new version, but also to marketing errors by the competition. It is estimated that there were 400,000 workstations and 141,000 Windows NT servers in early 1995. In view of the improvements, the migration of existing systems with Windows NT 3.1 to the new version proceeded quickly. For Microsoft, the success of the new version came as a surprise, the operating system was partially sold out. The range of 32-bit Windows applications improved, with around 1,200 applications at the time. Microsoft itself also supported the operating system with 32-bit versions of Microsoft Word and Microsoft Excel .

Of the systems sold with Windows NT, RISC systems only accounted for five percent. DEC's attempt to establish computers with alpha processors using Windows NT as desktop PCs failed, so the company concentrated on the high-end market in order to find a niche there. Both DEC and NEC , which sold computers with MIPS architecture , hoped that the improved operating system would attract new visitors.

Windows NT 3.5 was originally supposed to offer support for the PowerPC architecture. However, IBM had to postpone the delivery of the PowerPC processors repeatedly, so it was decided not to deliver the PowerPC support for NT 3.5, as had happened with the Alpha AXP version of Windows NT 3.1, but a revised version of Windows NT 3.5 under the name Windows NT 3.51 . This was not least due to the large number of known bugs contained in Windows NT 3.5.

Individual evidence

  1. G. Pascal Zachary: SHOWSTOPPER! The breakneck race to create Windows NT and the next generation at Microsoft. E-Rights / E-Reads, New York 2009, ISBN 0-7592-8578-0 , pp. 285 .
  2. Zachary: SHOWSTOPPER! P. 309
  3. Zachary: SHOWSTOPPER! P. 310
  4. Zachary: SHOWSTOPPER! P. 311
  5. ^ A b c d Paul Thurrott: Windows Server 2003: The Road To Gold - Part One: The Early Years . January 24, 2003. Archived from the original on January 1, 2005. Retrieved on May 28, 2012.
  6. ^ A b Clair Whitmer: Chicago, Daytona releases on target . In: InfoWorld . 16, No. 9, February 28, 1994, p. 91.
  7. ^ Joanne Cummings: Visiting Daytona, Chicago and Cairo: A road trip designed to clarify what is what with Microsoft's product plans . In: Network World . 11, No. 26, June 27, 1994, pp. L1, L10.
  8. ^ Microsoft, TCP / IP, Open Source, and Licensing . Retrieved December 7, 2012.
  9. Kelley Damore, Doug Barney: Chicago user interface shines in latest version . In: InfoWorld . 15, No. 51, December 20, 1993, pp. 1, 83.
  10. ^ Doug Barney: Microsoft provides the first public demo of Daytona . In: InfoWorld . 16, No. 14, April 4, 1994, p. 5.
  11. Microsoft releases Windows NT Server 3.5 and Windows NT Workstation 3.5 to Manufacturing . September 13, 1994. Accessed on May 18, 2013.  ( Page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link /  
  12. Xin Huang: Microsoft Windows NT 3.5 Workstation and Server US Service Pack 1 is out. In: (Google Groups). January 13, 1995, accessed January 25, 2015 .
  13. Rick Smith: Service Pack # 2! In: (Google Groups). March 1, 1995, accessed January 25, 2015 .
  14. Microsoft Knowledge Base - How to Obtain Windows NT Version 3.5 US Service Pack . Retrieved December 7, 2012.
  15. a b c d e f g h Peter Siering: License recipes: Windows NT 3.5 workstation and server . In: c't . No. 12, 1994, p. 266 ff.
  16. ^ Doug Barney, Clair Whitmer: NT upgrade aimed at power users . In: InfoWorld . 16, No. 39, September 26, 1994, p. 21.
  17. Doug Barney: Microsoft set to ship Windows NT 3.5: Will bolster push into enterprise with SMS release . In: InfoWorld . 16, No. 38, September 19, 1994, p. 5.
  18. Ilan Greenberg: Windows NT 3.5 not alone: ​​pair of suites to back up OS . In: InfoWorld . 16, No. 38, September 19, 1994, p. 5.
  19. Rick Ayre, Amarendra Singh: OS / 2 Warp, Version 3, and Windows NT Workstation version 3.5 . In: PC Magazine . 13, No. 22, December 20, 1994, pp. 221-238. ISSN  0888-8507 .
  20. Microsoft Knowledge Base - STOP 7B When Not Updating File Systems for Windows NT 3.1 . Retrieved September 9, 2012.
  21. Microsoft Windows NT Workstation Installation Guide
  22. Microsoft Knowledge Base - STOP screen when installing Windows NT 3.5 on 386 SMP machine . Retrieved July 18, 2012.
  23. Windows NT 3.5 at
  24. ^ Rob Ward: NT finally becomes what it ought to be: Version 3.5 is a big leap from 3.1 . In: InfoWorld . 16, No. 40, October 3, 1994, pp. 1, 105.
  25. Poking Around Under the Hood: A Programmer's View of Windows NT 4.0 . Retrieved January 14, 2013.
  26. ^ Joel Diamond: Windows NT 3.5: a 1994 success story . In: Network World . 11, No. 51, December 19, 1994, p. 24.
  27. ^ Jason Pontin: Windows NT starts to pick up steam . In: InfoWorld . 17, No. 5, January 30, 1995, pp. 27, 30.
  28. ^ Yvonne L. Lee: Pentium, RISC workstations: NT makes headway in workstation market . In: InfoWorld . 16, No. 52, December 26, 1994, p. 10.
  29. ^ Yvonne L. Lee: NT 3.5 revives RISC vendors . In: InfoWorld . 16, No. 41, October 10, 1994, p. 18.
  30. Microsoft Knowledge Base - List of confirmed bugs in Windows NT version 3.5 . Retrieved March 24, 2013.