Editing Windows NT 3.51

{{Short description|Third major release of Windows NT, released in 1995}}
{{Use mdy dates|date=January 2020}}
{{Infobox OS
| name = Windows NT 3.51
| version of = [[Windows NT]]
| logo = Microsoft Windows NT 3.1 logo with wordmark.svg
| logo size = x110px
| logo caption = 
| screenshot = Windows NT 3.51.png
| caption = 
| developer = Microsoft
| website = 
| source_model = [[Closed source software|Closed source]]
| license = [[Commercial software|Commercial]] [[proprietary software]]
| supported_platforms = [[IA-32]], [[DEC Alpha|Alpha]], [[MIPS architecture|MIPS]], [[PowerPC]]
| kernel_type = [[Hybrid kernel|Hybrid]]
| userland = [[Windows API]], [[NTVDM]], [[Microsoft OS/2 subsystem|OS/2 1.x]], [[Microsoft POSIX subsystem|POSIX.1]]
| preceded_by = [[Windows NT 3.5]] (1994)
| succeeded_by = [[Windows NT 4.0]] (1996)
| first_release_date = 
| first_release_url = 
| GA_date = {{Start date and age|1995|5|30}}<ref name="reldates" />
| release_version = Service Pack 5 (3.51.1057.6)
| release_date = {{Start date and age|1996|9|19}}<ref name="reldates">{{cite web|last1=Adams|first1=Paul|title=Windows NT History|url=https://blogs.technet.microsoft.com/mrsnrub/2009/08/04/windows-nt-history/|website=Microsoft Build |date=August 4, 2009 | archive-url=https://web.archive.org/web/20091130223223/http://blogs.technet.com/mrsnrub/archive/2009/08/04/windows-nt-history.aspx | archive-date=November 30, 2009 | url-status=live}}</ref>
| marketing target = Business and Server
| support_status = {{Infobox
 |child=yes
 |label1=Server
 |data1=Mainstream support ended on September 30, 2000<ref name="NT3.51Sup"/><br />Extended support ended on September 30, 2002<ref name="NT3.51Sup">{{cite web
  |title=Microsoft Support Lifecycle for Windows NT 3.51
  |url=https://support.microsoft.com/en-us/lifecycle/search?alpha=windows%20NT%203.51
  |publisher=Microsoft |access-date=January 15, 2019}}</ref>
 |label2=Workstation
 |data2=Mainstream support ended on December 31, 2000<ref name="NT3.51Sup"/><br />Extended support ended on December 31, 2001<ref name="NT3.51Sup"/><br />
 }}
}}
'''Windows NT 3.51''' is the third major release of the [[Windows NT]] [[operating system]], developed by [[Microsoft]] for the data server and personal workstation markets.<ref><nowiki>https://dspace.qau.edu.pk:8080/jspui/bitstream/123456789/29833/1/COM</nowiki> 1354.pdf</ref> It was released on May 30, 1995, eight months following the release of [[Windows NT 3.5]]. The most significant enhancement offered in this release was that it provides [[client/server]] support for inter-operating with [[Windows 95]], which was released almost three months after NT 3.51. [[Windows NT 4.0]] became its successor a year later. Mainstream support for Windows NT 3.51 Workstation ended on December 31, 2000,<ref name="NT3.51Sup"/> and extended support ended on December 31, 2001,<ref name="NT3.51Sup"/> while Windows NT 3.51 Server mainstream support ended on September 30, 2000,<ref name="NT3.51Sup"/> followed by extended support on September 30, 2002.<ref name="NT3.51Sup"/> Both editions were succeeded by [[Windows NT 4.0]] Workstation and Windows NT 4.0 Server, respectively.

==Overview==
The release of Windows NT 3.51 was dubbed "the PowerPC release" at Microsoft. The original intention was to release a PowerPC edition of NT 3.5, but according to Microsoft's David Thompson, "we basically sat around for 9 months fixing bugs while we waited for IBM to finish the Power PC hardware".<ref>{{cite web |first=Paul | last=Thurrott |title=Windows Server 2003: The Road To Gold - Part One: The Early Years |url=http://www.winsupersite.com/reviews/winserver2k3_gold1.asp |publisher=SuperSite for Windows |date=January 24, 2003 |access-date=September 4, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20100604082534/http://www.winsupersite.com/reviews/winserver2k3_gold1.asp |archive-date=June 4, 2010 }}</ref> Editions of NT 3.51 were also released for the [[x86 architecture|x86]], [[MIPS architecture|MIPS]], and [[DEC Alpha|Alpha]] architectures.

New features introduced in Windows NT 3.51 include [[PCMCIA]] support, [[NTFS]] file compression,<ref>{{cite web|url=https://technet.microsoft.com/en-us/library/cc767961.aspx |title=Optimizing NTFS |work=Windows NT Magazine |via=[[Microsoft TechNet|TechNet]] |access-date=June 25, 2017 |first=Sean |last=Daily|date=February 20, 2014 }}</ref> replaceable [[WinLogon]] ([[Graphical identification and authentication|GINA]]), 3D support in [[OpenGL]], persistent IP routes when using TCP/IP, automatic display of textual descriptions when the mouse pointer was placed on toolbar buttons ("[[tooltips]]") and support for Windows 95 common controls.<ref>{{cite web|date=October 31, 2006|title=Windows NT 3.51 Product Overview|url=http://support.microsoft.com/kb/124814|url-status=dead|archive-url=https://web.archive.org/web/20071225070412/http://support.microsoft.com/kb/124814|archive-date=December 25, 2007|website=Support|publisher=[[Microsoft]]}}</ref>

In view of the significant difference in the kernel base, Windows NT 3.51 is readily able to run a large number of [[Win32]] applications designed for [[Windows 95]]. More recent 32-bit applications will not work, as the developers have prevented their application from working with any Windows version earlier than Windows 98, and also because some applications do not work properly with the older Windows NT 3.51 interface.

Despite this, Microsoft in their application releases muddied the issue, releasing [[32-bit]] versions of [[Microsoft Office]] right up to [[Microsoft Office 97|Office 97]] (the last version of Microsoft Office supported on NT 3.51), but relying upon [[16-bit]] versions of [[Internet Explorer]] technology from versions [[Internet Explorer 3|3.0]] to [[Internet Explorer 5|5.0]]. Web browsers based on and including [[Mozilla Firefox|Firefox]] were operable up to version 2.0.0.22, released in April 2009; they required a few manual file updates to work without compromising browsing security.<ref>{{cite web |title=System Requirements |work=Installation Instructions for SeaMonkey 1.1.19 |date=March 16, 2010 |url= http://www.seamonkey-project.org/releases/seamonkey1.1.19/installation#win_requirements |access-date=November 30, 2015}}</ref><ref>{{cite web|url=http://toastytech.com/guis/misc4.html|title=Misc Windows|last=Lineback|first=Nathan|year=2010|website=toastytech.com|page=4|access-date=November 30, 2015}}</ref><ref>{{cite web |last=Lineback |first=Nathan |title=Web Browsing fixes for NT 3.51, 95, and NT 4 |website=toastytech.com |url=http://toastytech.com/files/95browsing.html |access-date=November 30, 2015}}</ref>

Windows NT 3.51 is the last of the series to be compatible with the [[Intel 80386]] processor.

===NewShell===
On May 26, 1995, Microsoft released a test version of a shell refresh, named the ''Shell Technology Preview'', and often referred to informally as "NewShell". This was the first incarnation of the modern Windows GUI with the Taskbar and [[Start menu]]. It was designed to replace the Windows 3.x Program Manager/File Manager based shell with [[Windows Explorer]]-based [[graphical user interface]]. The release provided capabilities quite similar to that of the Windows "Chicago" ([[Microsoft codenames|codename]] for Windows 95) shell during its late beta phases; however, it was intended to be nothing more than a test release.<ref>{{cite web|last=Ruley|first=John D.|date=September 1995|title=NT Gets the Look But Not the Logo|url=http://winmag.com/library/1995/0995/09howtoc.htm|url-status=dead|archive-url=https://web.archive.org/web/20060314223207/http://winmag.com/library/1995/0995/09howtoc.htm|archive-date=March 14, 2006|access-date=September 4, 2009|work=How-To Columns|publisher=WinMag}} Internet Archive</ref> There was a second public release of the Shell Technology Preview, called ''Shell Technology Preview Update'' made available to [[MSDN]] and [[CompuServe]] users on August 8, 1995. Both releases held Windows Explorer builds of 3.51.1053.1. The preview program provided early feedback for the ''Shell Update Release'', the next major Windows NT version with the new interface built-in, which was released in July 1996 as Windows NT 4.0.

=== Updates ===
Five [[Service pack|Service Packs]] were released for NT 3.51, introducing both bug fixes and new features. Service Pack 5, for example, fixed issues related to the [[Year 2000 problem]].

==Hardware requirements==
{| class="wikitable" style="text-align:center;"
|+Windows NT 3.51 hardware requirements<ref>{{cite web|date=November 1, 2006|title=Windows NT 3.5x Setup Troubleshooting Guide|url=http://support.microsoft.com/kb/139733|url-status=dead|archive-url=https://web.archive.org/web/20070223030314/http://support.microsoft.com/kb/139733/|archive-date=February 23, 2007|access-date=September 4, 2009|website=Microsoft Support|publisher=Microsoft}}</ref>
|-
! Category
! Minimum requirement
|-
| [[Central processing unit|Processor]]
| [[Intel 386]] or [[Intel 486|486]] at {{nowrap|25 [[MHz]]}}
|-
| [[Random-access memory|Memory]]
| Workstation edition: 12 [[Megabyte|MB]]<br/>Server edition: 16 [[Megabyte|MB]]
|-
| [[Video card]]
| [[VGA]]
|-
| [[Hard disk drive]] standard
| [[Integrated Drive Electronics|IDE]], [[EIDE]], [[SCSI]] or [[Enhanced Small Disk Interface|ESDI]]
|-
| Free [[hard disk drive]] space
| 90 [[Megabyte|MB]]
|-
| Installation media
| [[CD-ROM drive]], 1.44 MB or 1.2 MB [[floppy disk drive]] or active [[Local area network|network connection]]
|}
Supported EIDE addressing schemes include [[logical block addressing]] (LBA), ONTrack Disk Manager, [[SyQuest Technology|EZDrive]], and extended cylinder-head-sector (ECHS).

==Support lifecycle==
{{Timeline Windows NT 3.x}}

==References==
{{Reflist}}

==External links==
* [http://www.hpcfactor.com/qlink/?linkID=15 HPC:Factor Windows NT 3.51 Patches & Updates Guide]
* [http://toastytech.com/guis/nt351.html More Information]
* [http://toastytech.com/guis/newshell2.zip Shell Update Release (file dates: 08/09/95)]

{{Microsoft Windows family}}

[[Category:1995 software]]
[[Category:Products and services discontinued in 2001]]
[[Category:Windows NT|3.51]]
[[Category:IA-32 operating systems]]
[[Category:MIPS operating systems]]
[[Category:PowerPC operating systems]]
[[Category:Microsoft Windows]]