DFSMShsm provides the capability to function independently of the device type to which data is being transferred. That is, when you define a volume to DFSMShsm, you specify its device type. DFSMShsm then does all the work of converting for different track capacities and different allocation specifications necessary to accommodate the data sets sent to various volumes. For most access methods, this device independence allows migrating or backing up a data set from one kind of device and recalling or recovering it to another kind of device.