Microsoft Windows NT 3.51

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Windows NT 3.51
Windows NT 3.1 Logo.png
developer Microsoft
License (s) Microsoft EULA ( Closed Source )
First publ. May 30, 1995
Current  version 3.51 Build 1057 (SP 5) (September 23, 1996)
ancestry \ Windows NT
Architecture (s) x86 , MIPS , Alpha AXP , PowerPC

Windows NT 3.51 is an operating system from Microsoft . It represents a technical further development of Windows NT 3.5 . The system APIs have been extended and thus support newer 32-bit applications.


The previous operating system, Windows NT 3.5, was originally intended to offer support for the PowerPC architecture. However, this was missing because IBM had to postpone delivery of the PowerPC processors repeatedly. As a result, Microsoft decided not to add PowerPC support for NT 3.5, as had happened with the Alpha AXP version of Windows NT 3.1 , but to release it as part of a revised version of Windows NT 3.5 under the name Windows NT 3.51.

The operating system was first announced in February 1995. The final version NT 3.51 was released in May 1995 in the USA. Support ended on December 31, 2000 for end customers and on December 31, 2001 for corporate customers. After that, there were no more security updates for newly discovered security gaps.

A total of five service packs have been released:

title date size
Service Pack 1 August 9, 1995 ?
Service Pack 2 October 11, 1995 7.5 MB (x86)
? MB (AXP)
11 MB (MIPS)
10.3 MB (PowerPC)
Service Pack 3 December 14, 1995 7.5 MB (x86)
11.7 MB (AXP)
11.1 MB (MIPS)
10.3 MB (PowerPC)
Service Pack 4 March 14, 1996 9.9 MB (x86)
14.9 MB (AXP)
14 MB (MIPS)
13.3 MB (PowerPC)
Service Pack 5 September 23, 1996 12.4 MB (x86)
18 MB (AXP)
17.7 MB (MIPS)
16.1 MB (PowerPC)

After Service Pack 5, a few individual hotfixes were released. These concerned, for example, support for the euro symbol and AGP graphics cards.


The main innovation in Windows NT 3.51 is the support of the PowerPC as the fourth processor architecture. The other innovations of Windows NT 3.51 compared to its predecessor 3.5 are limited. For example, PCMCIA devices are supported. If the system is installed on an Intel Pentium with FDIV bug , Windows NT 3.51 offers to switch off the coprocessor in order to circumvent the problem.

Data compression was introduced for the NTFS file system , which allows individual files or entire directories to be compressed, although this has a negative impact on performance.

The biggest change, however, is the addition of numerous APIs from Windows 95 , which was under development at the time , so that Windows 95 programs can in most cases also run on Windows NT 3.51, provided they are not based on components that are incompatible with Windows NT (such as DirectX ). Windows NT 3.51 contains a driver for the HPFS file system of OS / 2 for the last time , although in contrast to Windows NT 3.5 no partitions can be formatted with the HPFS file system.

In preparation for Windows NT 4.0 , Microsoft offered the Windows 95 user interface as a download for Windows NT 3.51. Although this was originally intended for developers to adapt their software to the new user interface, it was also used by numerous end users.

Windows NT 3.51 comes with a CD-ROM and three 5.25 "boot disks as well as a 3.5" diskette set, consisting of 23 diskettes for the workstation and 42 diskettes for the server.

System requirements

Minimum requirement

  • Processor: Intel 386 DX (or compatible) 25 MHz or MIPS R4000 / Digital Alpha AXP / PowerPC
  • 12 MB RAM (Intel)
  • 90 MB hard disk space (with all updates and NTFS more)
  • Depending on the installation variant, floppy or CD-ROM drive (reinstallation with a suitable boot CD (e.g. from Windows 98) is also possible without a floppy drive)
  • VGA graphics card or better
  • mouse and keyboard


  • 486 DX / Pentium from 66 MHz
  • > 24 MB RAM
  • 250 MB hard disk space (plus space for applications)
  • CD drive (burner or DVD drive not directly supported, possibly with third-party drivers?)
  • SVGA graphics card

Web links

Individual evidence

  1. 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.
  2. ^ Jason Pontin: Multithreaded OLE support comes to NT . In: InfoWorld . 17, No. 16, February 6, 1995, p. 27.
  3. Euro Currency Not Available in Windows NT 3.51 Character Sets . In: Microsoft Knowledge Base . Retrieved December 16, 2012.
  4. AGP Video Support for Windows NT 3.51 and 4.0 . In: Microsoft Knowledge Base . Retrieved December 16, 2012.
  5. ^ Peter Siering: Unadorned Pearl: Windows NT 3.51 . In: c't . No. 8, 1995, p. 82 ff ..
  6. Volker Weber: HPFS despite Windows NT 4.0. In: c't. April 1996, accessed October 14, 2012 .
  7. NT 4.0: Windows NT 3.51 with 95 interface. In: c't. March 1996, accessed December 16, 2012 .