VMSTAR and multi-volume tape archives.

[Korendyk]

As I investigate this further, I thought I
would post a quick query, in case someone
might provide insight and prevent me from
proceeding down a wrong path :-)

I have often used VMSTAR (V3.4-1) to retrieve
files from a UNIX tar tapes (or files). But I
received a tape that reports the following
error when I try to list the contents:

$ vmstar/list mkb500:
tar: directory checksum error for ...
$

I am able to DUMP the contents (the first
dozen blocks or so) and to copy (DCL COPY)
without any errors, so I suspect the tape
is physically undamaged.

I'm told the tape is the first tape of a
3 volume tar set, created on a Tru64 system.

Is there something different about a
multi-volume tar set of which I'm not
(yet) aware?

Are there any other tools besides VMSTAR
available on OpenVMS that I could try?

Any ideas or suggestions are welcome.

\bill

[Hoff]

When last I looked, tar could checksum its header data but didn't have any particular integrity around the user data; it was prone to tape errors, and depended entirely on the tape drive for error recovery.

Depending on the error, COPY might well work (or not see the errors) and tar might get snarky.

tar tapes aren't all that common in recent times, and that and the reference to Tru64 Unix could imply this is rather old tape media.

Does a Unix box read the media?

Are you still working with that simh emulation of a VAX?

What sort of OpenVMS configuration and what sort of tape drive is involved here?

I'd be tempted to block copy the contents into the server and see if I could use the "recent" LD tape support.

And I'm going to guess you don't have an easy way to recreate the media?

[Korendyk]

First off, my apologies to all. I should
not inquire while 'still investigating',
but rather wait until I'm well into the
investigation. And I should stop believing
what people tell me is on a tape. A detailed
check of the tape shows it is not a tar tape.
Sigh. And Sorry.

A quick answer to Hoff. Yes, old media, DAT,
from a site that held on to the archives
after moving away from devices capable of
reading them (but that's another story).
I'm reading on OpenVMS/Alpha, and once a
DCL COPY finished, it was easy to see that
the format was not as expected.

I will close this thread before anyone
else follows me down the road to ...

\bill

[Korendyk]

Again, my apologies for this. Next time,
well, I'll probably make the same mistakes ;-)

\bill

[Steven Schweda]

> $ vmstar/list mkb500:
> tar: directory checksum error for ...

So, you get the complaint before it does the
first file?

You might try the latest thing you can find
at:

http://antinode.info/ftp/vmstar/

but I wouldn't bet much on an improvement in
this case, depending on what, exactly, wrote
the tape. Bear in mind that "directory
checksum error" is tar-speak for "something
confused me". It's specific, but not very
informative.

> [...] 3 volume tar set [...]

I've been more concerned with archives on
disk, so I haven't looked into that, but I
would not bet that it can deal with multiple
tapes. (Discouraging comment in AAATODO.TXT,
for example.)

[Hoff]

On a good day, DDS/DAT is a MWMERM format.
(MWMERM: might write, might even read. maybe.)

[Steven Schweda]

> Is there something different [...]

I don't see how there could be. I don't
think that "tar" knows that it'll need more
than one volume until it hits the end of the
first one.