Windows NT

From ReactOS

Windows NT is Microsoft's 32-bit OS. Most versions are sold under a name devised by marketeers. Originally Microsoft was developing OS/2 for IBM. At some point in time, Microsoft thought they would be better off by selling a 32-bit Windows version themselves instead, so they broke up with IBM and started getting Windows NT ready for the market.

Windows NT 3.1
It started with Windows NT 3.1 which never has enjoyed much popularity.
Windows NT 3.1 was Microsoft's first 32-bit Windows. The number 3.1 can be confusing since it could mean there were prior releases, but it's version 3.1 because it came out in the time of Windows 3.1.

Windows NT 3.5

Windows NT 3.51
This was the last version with the GDI fully in user mode (USERSRV.DLL) and with the Windows 3.1 GUI.

Windows NT 4.0
The next version was Windows NT 4.0 and improved a lot over Windows NT 3.1 in stability and performance and got really popular in companies as server and/or workstation OS.

Windows NT 5.0 / Windows 2000
Windows NT 5.0 is better known as Windows 2000 and for one introduced the Active Directory.

Windows NT 5.1 / Windows XP
Windows NT 5.1, AKA Windows XP features a number of improvements and additions over Windows 2000 on areas such as the GUI (themes), security and compatibility. The 'Home'-version was the first 'NT' version of Windows that was designed for the home user, and a real improvement over the earlier mainstream Windows versions: Windows 95, Windows 98 and Windows ME (Millenium Edition).

Windows NT 5.2 / Windows 2003
Windows NT 5.2, AKA Windows 2003 is the new collaboration for both the client and server OS from Microsoft. Known products are Windows Server 2003 in the flavors 'Standard'/'Enterprise'/'Datacenter'/'Web'/'Small Business'/'x64' Edition and Windows XP Professional 'x64' Edition.

Windows NT 6.0 / Windows Vista
Windows NT 6.0, AKA Windows Vista is a new approach from Microsoft to make a versatile OS of the future; it is scheduled for 2006. Vista is based on Windows Server 2003 with XP features. There may be atleast seven flavors.

Relation to ReactOS

ReactOS's original genesis, FreeWin95, was aimed at cloning Windows 95. After this failed, FreeWin95 re-emerged as ReactOS and was aimed instead at the better regarded Windows NT 4.0.

ReactOS when finalized should be able to run all programs that run on Windows NT.