SCO UNIX cpio allows no valid backup?!

[sl3h7 at cc.usu.edu]

cpio backup problems:

How to get standard cpio package that will verify multiple tape
backup?   On some systems, notably those using archive tape drivers,
the second tape does not produce a valid verify -- bad magic
error encountered.  I beleive that the tape driver is reporting
that it does a write of the last block on the first tape when
in fact it does not.  The verify passes the first tape, but
after reading a bit of the second tape blows up with the
"bad magic, out of sync " error.  This error may be avoided
by using another program to filter the output to cpio
rewriteing the last block of the previous tape.  However, on
those systems where the last block of the previous tape really
is written, the use of the filter would prove disasterous again.

What is needed: a standard driver, cpio driver, that works 
everywhere.

Please address responces to Charlie.
Standardize, Standardize, Standardize   UNIX!!!