GNU tar - Tape Positioning Go to the first , previous , next , last section, table of contents . Just as archives can store more than one file from the file system, tapes can store more than one archive file.
Tape drives write one tape mark between files, two at the end of all the file entries.
When you use tar to read or write archive data from a tape device, the device will begin reading or writing from wherever on the tape the tape head happens to be, regardless of which archive or what part of the archive the tape head is on. Before reading an archive, you should make sure the tape head is at the beginning of the archive you want to read. If you want to add new archive file entries to a tape, you should advance the tape to the end of the existing file entries, backspace over the last tape mark, and write the new archive file.