.       RBF40   -- READ ONE FILE 40 ITEM (BACKWARDS)
.
.       CALLING SEQUENCE -              RBF40 EOF
.       EOF IS THE TRANSFER LOCATION FOR END OF FILE,
.       ITEM IS LEFT IN A0.
.
RBF40*  PROC    1,6.
        L       A1,F40J
        JGD     F40I,$+3
        LMJ     B11,RBF40E              END OF BUFFER (OR FILE)
        J       RBF40(1,1)              END OF FILE
        L       A0,0,*A1
        S       A1,F40J
        END
OBF50*  PROC    1 .                     . OPEN TO READ BACKWARDS F50
        L       A0,F50J
          L,H2     A1,F50+6
        ANH     A0,(2,NBCW)
        AN,M    A0,0,A1
        S       A0,1,A1                 . STORE ITEM CPUNT
        BCLOTM  F50                     CLOSE AND MARK BLOCK OUTPUT
        B$OPNB  F50                     OPEN FILE (BACKWARDS)
        SZ      F50I
        END
OWF51*  PROC    1 .                     . OPEN TO WRITE F51
        BOPNW   F51A                   SELECT FIRST BUFFER
          L,H2     A0,F51A+6
        AH      A0,(1,NBCW)             . SKIP FIRST TWO WORDS
        S       A0,F51J
          L,M      A0,BUFN
        S       A0,F51I
        END
OFF51*  PROC    1 .                     . OPEN TO READ F51
        L       A0,F51J
          L,H2     A1,F51A+6
        ANH     A0,(1,NBCW)
        AN,M    A0,0,A1
        SSA     A0,1
        S       A0,1,A1                 . STORE ITEM COUNT
        BCLOT   F51A                   CLOSE BLOCK OUTPUT
        B$OPNF  F51A                   OPEN FILE (BACKWARDS)
        SZ      F51I
        END