Internet Information Server (IIS) is a powerful Web, FTP, and GOPHER server designed specifically for Windows NT. It uses a worker thread model (as opposed to a "thread per client" model) to provide the ability to service an extremely large number of connections with high performance. It also takes advantage of the new performance-boosting Microsoft Internet API set, which includes calls such as TransmitFile() and AcceptEx().
All three services run from within the same process (inetinfo.exe) and share resources such as worker threads and cached file handles. IIS has configurable logging that supports both text files and logging directly to a database by using ODBC. IIS also supports the use of sophisticated databases on the "backend" so that access to a database can be achieved by using a standard Web browser. In many cases a database is easier to maintain than a large number of static HTML files.
IIS ships with Windows NT Server 4.0, and versions for Windows NT Server 3.51 are available from www.microsoft.com. Microsoft Internet Information Server is not designed (or licensed) to run on Windows NT Workstation. More details are available from the Microsoft Web site.