how universal is tar format? SYSV?

[Barry Shein]

We have a 3B5 running SYSV and and 4.2bsd VAXen. Yes, tar is
compatible between these two (in spite of things that *might*
have broken it.)

Unfortunately, it seems that our SYSV tar won't read tar
tapes created on 4.2bsd with a blocking factor >10 so
be warned. (I also swear that twice when I was writing
tar tapes to our TU78 on our VAX with blocking factor of
one it tripped the circuit breaker in the tape drive!!)

As for cpio, all I know is that the standard cpio format
VAX SYSV source release from AT&T would *not* read off
on our 3B5, no matter what combination of byte/word swap
etc (-B) flags was tried. Not having cpio (it was on the
#@!#@ tape!) I wrote a trivial program I call 'cpi' that
will suck off a range of files from a cpio tape and create
all necessary directories etc as expected (won't write a tape.)
If anyone wants it it's a hack (only needed it till I got
cpio.c off) but hey, it's <100 lines of C, you can clean
it up yourself, and it works, just ask.

	-Barry Shein, Boston University