Specifying KEEP instructs the system to keep a data set intact until a later step or job requests that the data set be deleted or cataloged or until after an expiration date or retention period, if specified.
For data sets on direct access, the entry in the VTOC describing the data set and the data set itself are kept. For data sets on tape, the volume is rewound and unloaded, and a KEEP message is issued to the operator.