1117	 Polyphase Sorting With Overlapped Rewind	 A variation of the polyphase merge technique of sorting is described which permits one tape at a time to be rewound while the merge is continued on the remaining tapes. The result is the overlapping of a major portion of the rewind time. The technique should be considered whenever a sort is written to operate on five or more tapes that cannot be read backwards. The savings of the overlap method appear to increase as the number of available tapes is increased.
