Parameter in IEASYSxx (or supplied by the operator)

APF=xx
The two characters (A-Z, 0-9, @, #, or $), represented by xx, are appended to IEAAPF to identify the IEAAPFxx member. If the APF list is not explicitly defined (via the APF system parameter, the default IEAAPF00 parmlib member, or APF statements within PROGxx via the PROG system parameter), then only SYS1.LINKLIB and SYS1.SVCLIB will be APF-authorized during the IPL.
Note: In addition, any module in the link pack area (pageable LPA, modified LPA, fixed LPA, or dynamic LPA) will be treated by the system as though it came from an APF-authorized library. Ensure that you have properly protected SYS1.LPALIB and any other library that contributes modules to the link pack area to avoid system security and integrity exposures, just as you would protect any APF-authorized library.