Tar reads and writes to the tape device by default (compiled-in device) specifying  tar -tf tape0 on the command line attempts to extract the tar file "tape0" in the current directory to stdout. To see the archive contents from the tape:  tar -t. To extract from the tape onto disk:  tar -x. If tar doesn't see the tape for some reason then using the -f switch with the full device path  tar -tvf /dev/tape0 may work or it may not work depending on whether /dev/tape0 is a valid block device on your system. One problem is that you may have to set the correct blocksize to avoid an error. Try a blocksize of 20. If all else fails you may need to delve into the driver code for your particular tape drive to see what parameters it expects.