Computers running Windows NT Server 4.0 must be running Service Pack 5 or later before upgrading to Windows Server 2003. Once Service Pack 5 or later has been installed, you can upgrade directly to Windows Server 2003 without having to install Windows 2000. If you are doing a clean install, there is no need for installing the service pack.
Upgrading to Equivalent Operating System
A first step in choosing the best operating system is determining the nearest equivalent to what you are now running. Except for Web Edition, all Windows Server 2003 operating systems map directly to existing Windows 2000 operating systems, as shown in Table 1. The Web Edition, which is ideal for rack-mounted Web support deployments, is a completely new operating system, and so it does not have an equivalent in the Windows 2000 family of operating systems.
Table 1 Upgrading to an Equivalent Operating System
Note that you can only upgrade to an equivalent or higher operating system. You can’t “downgrade” to a less powerful operating system, as some functionality might be lost in the process. This means you can’t move from Windows NT Server 4.0, Enterprise Edition (or other server products in the Windows NT Server 4.0 family), to Windows Server 2003, Standard Edition, without removing the earlier operating system and performing a new installation.
Also note that Datacenter Edition—which provides an integrated hardware, software, and service offering—is not available as an upgrade. It can be purchased through the Windows Datacenter Program and is delivered by Microsoft and qualified server vendors, such as original equipment manufacturers (OEMs).
For more information, see Windows Server 2003 Support at http://www.microsoft.com/windowsserver2003/support/ or the online Product Documentation for Windows Server 2003 at http://www.microsoft.com/windowsserver2003/proddoc/.
Verifying System Requirements and Hardware Compatibility
Before upgrading to Windows Server 2003, you will want to make sure that the computer you will be upgrading meets the recommended system requirements and that all hardware components are compatible with the operating system. If you have consistently upgraded your hardware for your Windows NT Server 4.0 systems, this may not be an issue, but if your current servers are running on older computers, you may wish to consider installing Windows Server 2003 on new computers.
The most significant area of change is the recommended processor speed. While Windows 2000 required a 133 MHz or faster processor, Microsoft recommends a 550 MHz or faster processor for Standard Edition and Web Edition, and a 733 MHz or faster processor for Enterprise Edition and Datacenter Edition. Memory and disk space requirements are much the same.
*Important: The 64-bit versions of Windows Server 2003, Enterprise Edition, and Windows Server 2003, Datacenter Edition, are only compatible with 64-bit Intel Itanium-based systems. They cannot be successfully installed on 32-bit systems.