For ISO/ANSI tape volumes, DFSMSdfp only supports output to ISO/ANSI Version 3 or Version 4 and input from either ISO/ANSI Version 1, Version 3 or Version 4. If a label version conflict is detected during an output request to the first data set on a volume, the WTOR message IEC704A C is issued to the installation operator to get information for rewriting the volume label as a Version 3 or Version 4 label. If you do not want the operator to provide the label information (volume serial number, owner identification, and volume access code), you can use the WTO/WTOR message processing facility to intercept message IEC704A C and provide this information.

The name of the general purpose WTO/WTOR message processing installation exit is IEAVMXIT. You can use this installation exit or a message-specific installation exit routine (one that you specify on the USEREXIT parameter in the MPFLSTxx member of SYS1.PARMLIB) to process WTOR message IEC704A.