The Request Subsystem Version Information Call (SSI function code 54) provides a requesting program the ability to obtain version-specific information about a user-supplied subsystem. The information in Request Subsystem Version Information Call — SSI Function Code 54 describes what happens when SSI function code 54 is issued to the IBM-supplied subsystems (master or JES) by user-provided calling programs or routines.

The information that follows describes what a user-supplied subsystem needs to provide so that it can process incoming SSI function code 54 requests from callers that request information like the information provided by the two IBM-supplied subsystems. The user-supplied subsystem must then provide both the function routine to handle this request, as well as the information concerning the specific returned information. The user-supplied subsystem must provide information to the callers, because all version information returned to the caller is defined by, and has meaning only to, the user-supplied subsystem.