Maybe you were thinking of the IBM DITTO product? It's available for VSE, VM/CMS and z/OS. Its tape map function reads a tape and tells you how many actual feet wer e written. From the DITTO manual: TMP (Tape Map) Purpose Summarize tape contents. For a specified number of files on the tape, this function prints the contents of the first block or blocks, the
number of records, the minimum and maximum block sizes, the size of the file, and the amount of tape used. You can summarize the contents of the entire tape, or you can limit the summary to a specific number of tape files, and, within each tape file, t o a specific number of blocks.
