Windows Server 2003 is the latest in Microsoft's line of server operating systems and is based on the Windows NT and Windows 2000 platforms. Version-wise, Windows Server 2003 is roughly equivalent to Windows XP. In fact, both Windows Server 2003 and Windows XP were originally code-named Whistler; Microsoft released the desktop operating system first as Windows XP and spent some additional time refining the server-specific features included only in Windows Server 2003.
If you're familiar with Windows XP, many of Windows Server 2003's new features (such as CD burning) will be familiar to you because they were first included in Windows XP. For performance reasons, however, Windows Server 2003 lacks Windows XP's new user interface design, so the two seem much more different than they really are.
One of the biggest questions on your mind is probably, "How different is Windows Server 2003 from Windows 2000 Server?" After all, Windows 2000 was a major change from the previous version?Windows NT Server 4.0. Windows Server 2003 is definitely a major change over Windows 2000 in terms of functionality, but it isn't as big a change as Windows 2000 was when it was first introduced. Instead, Windows Server 2003 builds on Windows 2000's features with several improvements. What makes Windows Server 2003 such a major change is that it builds on almost every one of Windows 2000's features; all those relatively minor changes add up to a major new operating system.
Windows Server 2003 also introduces an entirely new edition of the operating system: Windows Server 2003, Web Edition. The addition of Web Edition to the product line changes the way administrators must architect new servers, especially in a Web services or Web server environment. Windows Server 2003 also includes Microsoft's first 64-bit server operating system editions, providing additional architectural flexibility for administrators in high-demand, enterprise environments.