Windows Server 2008 is the name of the next server operating system from Microsoft. It is the successor to Windows Server 2003. It was known as codename Windows Server "Longhorn" until May 15, 2007, when Bill Gates announced its official title during his keynote address at WinHEC.
Windows Server 2008 is the server operating system containing many of the new client features from Windows Vista. This is a similar relationship to that between Windows Server 2003 and Windows XP.
It has been confirmed that this version of Windows Server supports x64 (64 bit), as well as x86 (32 bit) processors. IA-64 will be supported in the Datacenter Edition of Windows Server 2008. The IA-64 version will be optimized for high workload scenarios like database server and line of business applications. As such it is not optimized for use as a file server or media server. Microsoft has announced that Windows Server 2008 will be the last 32-bit server operating system that it will produce.