Windows Server 2003

Windows Server 2003 is the server counterpart of Windows XP. It Reached RTM on 2003-03-25. It comes in flavours of Datacenter, Web Server, Standard, Enterprise and Small Business (the latter is technically a separate version).

About R2 Version
An interim release was made, under the name Windows Server 2003 R2 on 2005-12-06.

Other versions
As well as the standard Windows Server 2003, several other editions were built on the NT5.2 kernel, including Storage Server 2003 R2 (released 2006-03-05), Compute Cluster Server 2003 (released 2006-06-09), Small Business Server 2003 R2 (released 2006-09-01) and Unified Data Storage Server 2003 (released 2006-12-05).

R2 RTM
This version is Windows Storage Server 2003 R2.