DFSMSdss moves data based on physical track images during physical processing. Because DFSMSdss moves data at the track level, the target device's track sizes must equal the source device's track sizes. Therefore, you can use physical processing only between like devices. Physical processing operates on volumes, ranges of tracks, or data sets. For data sets, physical processing relies only on volume information in the VTOC and VVDS for data set selection. Only that part of a data set that resides on the specified input volume is processed.