DUMPDS

The DUMPDS system initialization parameter specifies the transaction dump data set that is to be opened during CICS initialization.

DUMPDS={AUTO|A|B}
Valid values are as follows:
AUTO
For all emergency or warm starts, CICS opens the transaction dump data set that was not in use when the previous CICS run terminated. This information is obtained from the CICS local catalog.

If you specify AUTO, or let it default, code DD statements for both of the transaction dump data sets, DFHDMPA and DFHDMPB, in your CICS startup job stream.

A
CICS opens transaction dump data set DFHDMPA.
B
CICS opens transaction dump data set DFHDMPB.