Windows NT 3.51 is the third major release of Microsoft's Windows NT line of operating systems. It was released on May 30 1995, nine months after its predecessor, Windows NT 3.5. The release provided two notable feature improvements; firstly NT 3.51 was the first of a short-lived outing of Microsoft Windows on the PowerPC CPU architecture. The second most significant enhancement offered through the release was that it provided client/server support for inter-operating with Windows 95, which was released three months after NT 3.51. Windows NT 4.0 became its successor a year later; Microsoft continued to support 3.51 until December 31 2001.
he 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". Editions of NT 3.51 were also released for Intel's x86, MIPS, and DEC Alpha architectures.
Despite the significant difference in the kernel base, Windows NT 3.51 was readily able to run a large number of Win32 applications designed for Windows 95. Despite this, Microsoft in their application releases muddled the issue, releasing 32-bit versions of Microsoft Office right up to Office 97 SR2b, but relying upon 16-bit versions of Internet Explorer technology.
Microsoft also released test versions of a shell refresh, named the Shell Technology Preview. The update was designed to replace the Windows 3.x Program Manger/File Manager based shell with a Windows Explorer-based graphical user interface. The release provided capabilities quite similar to that of the Windows "Chicago" (codename for Windows 95) shell during its late beta phases, however was intended to be nothing more than a test release. There were two public releases of the Shell Technology Preview, made available to MSDN and CompuServe users; May 26 1995 and August 8 1995. Both held Windows Explorer builds of 3.51.1053.1. The Shell Technology Preview program was ultimately never saw a final release under NT 3.51. The entire program was moved across to the Cairo development group who finally integrated the new shell design into the NT code with the release of NT 4.0 in July 1996.
Five Service Packs were released for NT 3.51, which introduced both bug fixes and new features. Service Pack 5, for example, fixed issues related to the Year 2000 problem.
NT3.51 was the last of the series to run on a '386, and is in some ways the least resource-hungry of the NT line. This, and its ability to run at least some of the common control API, means that it still finds a place for occasional use on older machines. Private modifications (SuperPacks) to enable it eg to read FAT32 are available.