At IPL

To add your own resource managers for installation applications at IPL, place their names in the CSECT IEAVTRML, which is provided by MVS™.

Initially, IEAVTRML consists of four 12-byte entries, each containing zeros. You can modify each of the first three 12-byte entries (using the AMASPZAP service aid as described in z/OS MVS Diagnosis: Tools and Service Aids) to contain a module name in the first eight bytes; the last four bytes of each entry are reserved and always contain zeros. The last entry must also contain all zeros, to indicate the end of the list. A typical entry for the CSECT might be:

DC   CL8'MODULENM'
DC   XL4'00'

To add the names of more than three installation-written resource managers, create an entry for each module and a final entry that contains all zeros. Then assemble your modified IEAVTRML and use the modified CSECT to replace the existing IEAVTRML module in load module IGC0001C in SYS1.LPALIB. Place each installation-written resource manager in SYS1.LINKLIB (or a library concatenated to SYS1.LINKLIB through a LNKLSTxx member of SYS1.PARMLIB) or SYS1.LPALIB. If every routine named in IEAVTRML is not present in one of these libraries, the IPL fails.

Using the IEAVTRML method to add installation-written resource managers is still supported, but is no longer recommended because of performance considerations. IEAVTRML exits receive control by means of a LINK that will be issued when both EVERY task in EVERY address space terminates and EVERY address space terminates. Placing an exit routine in the LNKLST concatenation has caused significant performance delays during concurrent IPLs of multiple systems in a sysplex. In extreme cases, task termination delays can result in storage shortage in the address space that delays and might prevent successful IPL.