ACEE and related control blocks

The first time a RACROUTE REQUEST=VERIFY is issued for an address space, there is only one ACEE (accessor environment element), and it is pointed to by the ASXB (see Figure 1).

For any subsequent task in the address space (multiple users), the following cases could occur:

A table of pointers to ACEEs is set up in the address space. This occurs for CICS® (Customer Information Control System) or IMS™ (Information Management System) address spaces.
Another ACEE is created when the VERIFY request is issued. This ACEE is pointed to only by the TCB for that task. See Figure 2.
When a third-party AUTH request is used (USERID was specified on the RACROUTE REQUEST=AUTH), the ACEE is pointed to by an existing ACEE. See Figure 3.

For more information about how ACEEs are created and which ACEE is used, see z/OS Security Server RACF System Programmer's Guide.

Figure 1. Control block overview: ACEE in a single-user address space

Figure 2. Control block overview: ACEE in a multiple-user address space

Figure 3. Control block overview: ACEEs when third-party AUTH request is used