Question about mag tapes under Eunice

[Joel C. McClung]

Maybe someone can enlighten me as to why this works the way it does:

My wife works on a Eunice system (version 3.2).  I gave her a mag
tape with some stuff written on it in tar format (V7 tar, 1600 bpi).
She was able to extract it using tar on her Eunice machine with no
problems.  She then put some things on the tape to give me, again,
using tar.  She had no problem putting things ON the tape, but when
she tried to get a table of contents listing, tar complained about
the block size being zero and no TOC was generated.  She recreated the
tape with tar, only this time put a blocking factor (tar cvb 20 files).
Again, there was no error, but when she tried a TOC, the same error
happened.  At this point, she gave up and gave the tape back to me.
I mounted the tape on my machine and managed to generate the TOC AND
extract the tape with no problems (and yes, the files were the files
that SHE put on the tape, not the ones I put on).  I don't understand..

Why is that VMS/Eunice can't read its own writing?

--
Joel C. McClung
(703) 556-2644
{seismo,allegra,ihnp4}!rlgvax!prcrs!joel