[SLUG] CPIO from a DG/UX tar

From: Matt Miller (mmiller1@mptotalcare.com)
Date: Thu May 30 2002 - 20:52:30 EDT


I am wondering if anyone has encountered anything like this:

I have some tape archives from an old DG/UX system created before I
started at my current employer. I have tried without much success
reading the tapes with GNU tar on Linux.
 
    mt -f /dev/st0 rewind
    tar tvbf 32 /dev/nst0 >> foo.bar

GNU tar was having problems reading all the headers from the tape and
bailing with nondescript errors. I could only produce a partial listing
from the tapes. I ran strace and realized there were some problems
reading headers due to "icompatability" issues. I was able to pull the
original backup script off the tape using GNU tar.

    tar xvbfP 32 /dev/st0 ./../path_to/backup

Here is an excerpt of how the archive was being written from the
original script:

    # Change to the root directory and use relative path from there.
    cd /
    tar cvf /dev/rmt/$TAPE ./..
    
So, I gave up on tar and decided I would try to read the tape with cpio.

    cpio --format=tar --block-size=32 -tvF /dev/nst0 >> foo.bar

OK. I ran grep against the output and found the data I was looking for.

    grep "./../some/data" foo.bar
    
Great. But now here is my problem; I can't seem to extract the data from
the tape archive with cpio. (I just need the data...I don't care about
preserving any file attributes.)

    cpio --format=tar --block-size=32 --no-absolute-filenames -ivdF
    /dev/nst0 ./../some/data
AND
    cpio --format=tar --block-size=32 --no-absolute-filenames -ivdF
    /dev/nst0 "./../some/data"
AND
    cpio --format=tar --block-size=32 --no-absolute-filenames -ivd
    "./../some/data" -F /dev/nst0
AND
    cpio --format=tar --block-size=32 --no-absolute-filenames -ivd
    "./../some/data" < /dev/nst0
    
All of the above commands run for about an hour, exit gracefully with
the amount of blocks read, and return with no data recovered. Any ideas?
(Sorry for the length).
Thanks.

-- 
Matt Miller
Systems Administrator
MP TotalCare, INC
gpg public key id: 
08BC7B06




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