A catalog describes data set attributes and indicates the volumes on which a data set is located. Data sets can be cataloged, uncataloged, or recataloged. All system-managed DASD data sets are cataloged automatically in a catalog. Cataloging of data sets on magnetic tape is not required but usually it simplifies users jobs. All data sets can be cataloged in a catalog.

Non-VSAM data sets can also be cataloged through the catalog management macros (CATALOG and CAMLST). An existing data set can be cataloged through the access method services DEFINE RECATALOG command.

Access method services is also used to establish aliases for data set names and to connect user catalogs to the master catalog. See z/OS DFSMS Managing Catalogs for information about using catalog management macros.