Read-Backward Polyphase Sorting Read-backward Polyphase sorting provides more efficient use of the tapes available to a sort than most other sorting techniques. Backward Polyphase produces a continuous merging process from n-1 tapes where n is the total number of tapes being used in the sorting process. Any of the available presorting techniques may be used in conjunction with the Polyphase merge sort provided that the presort has the capability of producing both ascending and descending strings and distributing the strings on the various tapes as required by the Polyphase Merge. CACM May, 1963 Gilstad, R. L. CA630506 JB March 14, 1978 11:28 AM 1117 4 861 2017 4 861 2146 4 861 861 4 861 1117 5 861 2017 5 861 2146 5 861 677 5 861 860 5 861 862 5 861 861 5 861 861 5 861 861 5 861 849 6 861 850 6 861 851 6 861 852 6 861 853 6 861 854 6 861 855 6 861 856 6 861 857 6 861 858 6 861 859 6 861 860 6 861 861 6 861 861 6 861 861 6 861 861 6 861 861 6 861 862 6 861 862 6 861 862 6 861 863 6 861 863 6 861 864 6 861 865 6 861 866 6 861 299 6 861 479 6 861 636 6 861