Raw vs Block Tape I/O

[G.TOMASEVICH]

There was a comment on rarely using the block version of mag-tape i/o.  On our
system, USG 4.2, 'cat' does not flush the last block if only partially full,
for block tape writes, so block i/o is worse than useless in that case.
Many commands seem to work either way on tape, though.  I prefer using raw, or
character-special mode, for reading, since it will correctly read any size
tape block that fits into the supplied buffer.  The main advantage of raw
tape i/o is using large buffers (and hence record size) to minimize the
amount of tape used up for inter-record gaps.