Tape to Tape Compare (option 4.9)

Use Tape to Tape Compare to compare, byte by byte, the data on one tape with the data on another. Tape to Tape Compare is particularly useful if you have made a copy of a tape, and want to check that the duplicate is exactly the same as the original.

When you select Tape to Tape Compare, the Tape to Tape Compare panel shown in Figure 1 is displayed.
Figure 1. Tape to Tape Compare panel
 Process   Options   Help
────────────────────────────────────────────────────────────────────────────────
 File Manager                 Tape to Tape Compare

 Tapes:  No tapes allocated


 Input:
    DDNAME to use . ________     enter new name, or select one from above

    DDNAME to use . ________     enter new name, or select one from above

    Files . . . . . 1____        number of tape files, EOV, or EOD






 Command ===> _________________________________________________________________
 F1=Help      F2=Split     F3=Exit      F4=CRetriev  F7=Backward  F8=Forward
 F9=Swap     F10=Actions  F12=Cancel

You can compare an entire tape, or a specific number of files. Tape to Tape Compare stops processing as soon as it finds the first difference. Be sure to position the tapes as needed before starting the comparison.

To compare all the files on the tapes, enter EOV in the Files entry field. If you do not specify a value for Files, only one file (from the current block to the next tape mark) is compared.

When a difference is found, File Manager lists:
  • The two records that do not match
  • The lengths of these records on the two tapes
  • The location of the first different byte
  • The number of blocks and bytes compared

If no difference is found, File Manager lists the number of blocks and bytes compared.

Note: An input/output error is considered a difference, even if the same error occurs on both tapes.

For further information, refer to the online help or TTC (Tape to Tape Compare).