Backup programs (at least as early as the 90's) would get around this by creating index or catalog files for the backup tape, and keeping those locally. You cou

Backup programs (at least as early as the 90's) would get around this by creating index or catalog files for the backup tape, and keeping those locally. You could re-generate the catalog file by re-indexing the backup tape, but of course that took a considerable amount of time. If you were restoring to a new system and no longer had the catalog files, for example. Another benefit was that you could quickly browse the contents of your backups without having to read or even insert the tape.