When only one user ID can be associated with an address space, user-related information (ACEE) is anchored from the address space extension block (ASXB). For applications, such as IMS™, that permit multiple users per address space, as each user requires an ACEE, and the application can request RACROUTE REQUEST=VERIFY CREATE to return a pointer to the ACEE rather than anchoring it from the ASXB. The application must then keep track of user/ACEE relationships by passing the appropriate ACEE pointer to RACROUTE REQUEST=AUTH and RACROUTE REQUEST=VERIFY (CHANGE or DELETE), thus associating the correct ACEE with the user for whom processing is being done. RACROUTE REQUEST=VERIFY allows the invoker to specify a subpool from which the ACEEs and related storage can be obtained.

The program control option that provides protection for individual load modules does not provide protection for multiple users in an address space. If one user in an address space causes a program to be loaded, another user in the same address space can also execute the program.