There are two main subtrees in the Microsoft® Windows NT® registry where information is kept relevant to Microsoft® SNA Server: the SOFTWARE tree and the SYSTEM tree. Both of these are subtrees of HKEY_LOCAL_MACHINE. The SOFTWARE tree contains generic information about IHV link services, and the SYSTEM tree contains information about the individual components of those services. While reading the following topics, it may be helpful to view examples of what is being discussed by inspecting the registry of an existing system with several of the built-in link services installed.