In Optimizing Tape Usage, you used tape mount management to direct some of your tape data sets to two storage groups, TMMBUFxx and TMMBFSxx, to have the data sets managed by DFSMShsm. They migrate through the storage hierarchy and eventually reside on migration level 2 volumes. Migration level 2 volumes, and the volumes containing data sets written by DFSMShsm or your own applications directly to tape, can be system-managed. The addition of system-managed tape enables you to manage all types of storage media-DASD, optical disks, and tape volumes-in the DFSMS environment.