System-managed tape volumes are defined in the tape configuration database (TCDB). The TCDB is a catalog that is marked as a volume catalog (VOLCAT) containing tape volume and tape library records. For more information about the TCDB, see z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries.

System-managed tapes should be defined to the DFSMSrmm control data set for the volumes to be managed by DFSMSrmm. To define volumes to both DFSMSrmm and the TCDB, use the RMM ADDVOLUME subcommand for volumes not yet known to DFSMSrmm, and the RMM CHANGEVOLUME subcommand for volumes already defined to DFSMSrmm but not the TCDB. For information on using DFSMSrmm commands, see z/OS DFSMSrmm Managing and Using Removable Media.

When you use DFSMSrmm to request that a volume should move to a system-managed tape library, DFSMSrmm ensures volume information is recorded in the TCDB.