The link service installation system was written with the assumption that IHV link services would be installed from a disk during or after the initial SNA Server setup process. For each link service on a particular disk, main Setup looks in the root directory for its .INF, .SRL, and .HLP files, and expects to find a subdirectory of the same name as the .INF file (without the .INF extension) where all other files for that link service are kept. For example, a disk containing the link services FastLink and SlowLink would have in its root directory two .INF files (FASTLINK.INF and SLOWLINK.INF), two .SRL files (FASTDLG.SRL and SLOWDLG.SRL), two .HLP files (FASTLINK.HLP and SLOWLINK.HLP), and the directories FASTLINK and SLOWLINK. Other files for these link services (device driver binaries, libraries, configuration files, and so on) reside in their respective directories.