text: Windows Server 2003 ( sometimes referred to as Win2K3 ) is a server operating system produced by Microsoft , introduced on 24 April 2003 .
simplified: Windows Server 2003 is a server operating system produced by Microsoft . Introduced on April 24 , 2003 as the next version to Windows 2000 Server , it is considered by Microsoft to be the cornerstone of their Windows Server System line of business server products .