universal tar format -vs- byte swapped 9-track tapes

[John Gilmore]

> I have found one incompatibility - Plexus machines output swapped bytes.
> We received a Plexus-generated tar tape and had to do a dd swapb to be able
> to read it.  We complained to the originator (wasn't plexus) and they
> said it was a natural consequence of byte order.  That's crap - Our
> Pyramid is backwards from a VAX and we don't have any problem.  They
> just never realized that the Plexus tar should swap bytes to remain
> compatible with the rest of the world (I suspect that it was a wierd
> tape driver/hardware configuration)	

At Sun we had the same problem.  Reading our first externally generated
tape showed that our Multibus tape controller was writing the data it
in memory byte-swapped from the way our 68000 processors were reading
it from memory.  Of course we changed the kernel tape driver, not
'tar', and looked at controllers that would accept our byte order so we
wouldn't have to swap in the driver software.

Isn't it curious that tar format, like uucp format, is both universal
and undocumented?  I finally wrote a man page for it, which showed
a few surprises.  Like: which fields have trailing nulls and which
do not?