A non-unique user id is one that is not associated to a single owner, but instead can be used by more than one user. This function is support for compatibility in the runtime environment.
Link3270 State file, DFHMALSF, assignment for non-unique user ids provides the following processing:
Link3270 bridge facilities are required to run CICS applications in modeled flows that contain Link3270 server adapters. Link3270 bridge facility and state file processing for non-unique user id looks at processing requirements that arise when non-unique user ids are used with CICS Service Flow Runtime.
Using non-unique user ids in your Link3270 service flows will determine how CICS Service Flow Runtime assigns Link3270 State file information for allocated Link3270 bridge facilities that are used to execute CICS applications via the CICS Link3270 bridge mechanism. SeeRun time processing of non-unique user IDs using Link3270 bridge server adapters for a description of run time processing associated with LU assignments for non-unique user ids.