The Operating System

The SQL Server engine runs best on Windows NT Server, and your production applications are meant to run on SQL Server on Windows NT Server or Windows NT Enterprise. Although you can install the desktop version of SQL Server on Windows NT Workstation, Windows 95, or Windows 98, many SQL Server capabilities are not supported on the desktop version. (We discussed these limitations earlier in the chapter.) Memory management and the process scheduling behavior on Windows NT Server are better tailored to services such as SQL Server than is Windows NT Workstation, Windows 95, or Windows 98, which focus on desktop applications. The simple fact is that SQL Server runs better with medium to large workloads on Windows NT Server than on any other platform.

Support for SQL Server on a particular platform or version of Windows NT does not necessarily mean that it won't work with other configurations. But you should stick with the supported platforms for the following reasons:

• Only supported platforms get significant test coverage. An unsupported platform might seem to work, but a subtle problem might occur later.
• Authorized SQL Server support providers and Microsoft SQL Server Enterprise Technical Support (ETS) focus on the supported platforms; if your problem is specific to the unsupported platform, you might not be able to get enough help.
• Typically, a new release of SQL Server is targeted at the most recent (or sometimes an impending ) release of Windows NT Server and also supports the prior major release. As of this writing, Windows 2000 is already in Beta 2 release, so SQL Server 7 runs on Windows NT 4 (with Service Pack 4) and Windows 2000 (formerly called Windows NT 5). It is not supported on Windows NT Server 3.51 or earlier. If you try to run Setup on a Windows NT version earlier than version 4 with Service Pack 4, you will get an error and be prevented from continuing.

You can install SQL Server on any Windows NT Server in your domain, but for the best performance do not install it on your primary or backup domain controllers (PDCs or BDCs). Although SQL Server will run fine on a PDC or BDC, the controller's tasks of maintaining and replicating the Windows NT user database take up processing cycles and memory. In less resource- intensive environments, this usually doesn't make much of a difference, but if your system is part of a large domain, it is better to separate SQL Server processing from those activities.