You can use the DIAGNOSE command to accomplish two main tasks:

1. Check the dependent content of catalog records
2. Check the validity of the content of catalog records.

There are no special parameters needed for simply checking the content of a record. As with all DIAGNOSE jobs, specify the ICFCATALOG parameter when checking a BCS, and the VVDS parameter when checking a VVDS.

DIAGNOSE recognizes tape library and tape volume record types. DIAGNOSE checks the cell structure of the volume catalog.

To compare catalog information with VTOC information, you must use DIAGNOSE VVDS, to analyze a VVDS. When you use DIAGNOSE ICFCATALOG, only the BCS and related VVDSs are analyzed.

All records of the input BCS or VVDS are processed unless they are explicitly included or excluded.