DBCTL and XRF

An IMS DB/DC XRF subsystem can provide DBCTL service. There are no changes to the XRF functions or to the DBCTL functions in this case.

For an XRF takeover to complete in this environment, the CCTL must be able to broadcast a /SWITCH command to the XRF active subsystem. The CRC must be unique to each IMS region that specifies it.