Subject:   -33- What do I do when I can't read a tar tape made on
                another system?
Date: 04 May 1994 00:00:01 EST

  Glenn Randers-Pehrson <glennrp@BRL.MIL> says:
  You may be trying to read a non-byte-swapped tape on a byte-swapped
  device, or vice versa. Tar tapes written on SGI's QIC cartridge
  drive, using the default device, /dev/tape, are in byte-swapped
  format.  Sun tapes are usually not byte-swapped. On the IRIS, you can
  read non-byte-swapped tapes with

      tar -xvf /dev/tapens

  and you can write non-byte-swapped tapes destined for a Sun with

      tar -cvf /dev/tapens [directory_or_filename[s]]

  On the SUN, you can read byte-swapped tapes with

      dd if=/dev/rmt0 conv=swab | tar -xvf -

  Read the tar(1) (DIAGNOSTICS section) and tps(7M) manpages for the
  gory details.

  DAT tapes may have an additional problem: SGI DATs have a default
  blocking factor of 512 and HP DATs have a maximum blocking factor of
  128.  You can either rewrite your tape on the SGI with

      tar cvbf 20 /dev/tape files

  and read it on the HP (or whatever) with

      tar xvbf 20 /dev/tape

  or you can use 'dd' to translate like so,

      dd if=/dev/tape ibs=512b of=- obs=20b | tar xvf -

  where '512' is whatever blocking factor you used to write the tape.