Using the Tape Retention System (TRS) › TRS Processing Considerations › Changing the Controlling Data Set

Changing the Controlling Data Set

If a volume contains two or more data sets, one data set is identified as the controlling data set (CDS). This is the first data set by default. If another data set is more critical, you can change control to another data set:

• Specify the SPACE=(1,(1,4)) parameter on the DD statement of the controlling data set. This allows you to define the CDS at execution time through JCL.
• Add the CDS= system option into member TLMSIPO of CAI.CTAPOPTN to identify the controlling data set (see Chapter 3 of the Configuration Guide). This allows you to redefine the CDS without making modifications to the JCL.
• Use the UPV command with the CDS keyword to manually change the controlling data set to another data set. For example: UPV 123456,CDS=2.

If all data sets on the volume have the same retention criteria or if the first data set is the most critical, you can just let control default to the first data set on the volume.

Use the reports and displays to identify controlling data sets. They are flagged with an asterisk (*). If more than one CDS is identified, the second and subsequent CDSs are flagged with dollar signs ($) to indicate a conflict. Conflicting CDSs are also reported in the Tape Retention System Error/Exception Report, where they appear until the volume is manually scratched.