During PDSE initialization in a SYSPLEX environment, the system initializing PDSEs must establish communication through XCF with the other systems in the SYSPLEX in order to let the other systems know that PDSEs are accessible on the new system. Also, a system being varied offline must establish communication through XCF with the other systems in the SYSPLEX in order to let the other systems know that the PDSEs on the system are being taken off line are no longer accessible. This message is issued to indicate that the system has either started or completed establishing messaging between two systems. This message also is issued to notify you that EOM (End of Memory) processing for ASID aaaa was not successful. A dump accompanies the message in this case.

In addition when you IPL, restart the SMSPDSE address space, or issue the SET SMS=xx command you will see one of the Buffer Past Close messages. These messages let you know what the current state of buffering beyond close is for the PDSE address space (SMSPDSE or SMSPDSE1).