topic Re: DAT tape data block size problem in Operating System - HP-UX

DAT tape data block size problem

Glenn Bowley — Tue, 18 Sep 2001 11:47:36 GMT

Hello all-
I'm trying to recover some data that is on a DAT tape, but I'm getting the error "Tar: blocksize=2, directory checksum error"
I seem to remember this being a problem with using a tape created on a SUN workstation. However, I don't think this tape was created on a SUN workstation.
Any suggestions on how to restore some files on this tape?
Thank You

Re: DAT tape data block size problem

Carlos Fernandez Riera — Tue, 18 Sep 2001 12:00:23 GMT

do a dd

dd if=/dev/rm..... of=/tmp/f1 bs=10k

file /tmp/f1

If it shows tar file you can do

tar tvfb /dev/rmt/... 2

Or maybe it is other file format such us cpio.

Re: DAT tape data block size problem

Carlos Fernandez Riera — Tue, 18 Sep 2001 12:04:05 GMT

Please change :
dd if=/dev/rm..... of=/tmp/f1 bs=10k count=10

Re: DAT tape data block size problem

Glenn Bowley — Tue, 18 Sep 2001 12:14:26 GMT

Thanks for the information.
After trying this, I feel the tape may be blank.
After issuing the command, the system responds very quickly with no tape drive activity. The output file is only 1024 in size, so I don't think this works, or again, the tape is blank.
Thanks for the help though!

Re: DAT tape data block size problem

Carlos Fernandez Riera — Tue, 18 Sep 2001 17:30:01 GMT

Have you tryed more reads with norewind device (/dev/rmt/0mn)?

Maybe this is 1024 bytes is only a tape header.
do

cat /tmp/f1
or od -xc /tmp/f1

Re: DAT tape data block size problem

Glenn Bowley — Tue, 18 Sep 2001 19:06:55 GMT

Using the cat command, I get the message "ANSI standard label not yet implemented" ?????
Does this make any sense?
I have been using the /dev/rmt/0m to view the archive list.

Re: DAT tape data block size problem

Carlos Fernandez Riera — Wed, 19 Sep 2001 05:51:32 GMT

Every time i have seen this message i rejected tape as non valid tape.

DDS tapes have a internal header, and this mess refers, i think, that header has been not found.

Re: DAT tape data block size problem

Frank Slootweg — Wed, 19 Sep 2001 10:37:55 GMT

> Using the cat command, I get the
> message "ANSI standard label not yet
> implemented" ?????
> Does this make any sense?

This *probably* indicates that it is a fbackup(1M) tape. Use frecover(1M) or SAM to restore.

This will show the same message:

fbackup -i /etc/passwd -f - 2>/dev/null | head -1

Re: DAT tape data block size problem

Carlos Fernandez Riera — Wed, 19 Sep 2001 11:08:17 GMT

Frank:
maybe i am wrong. I remember this message from some new tapes.

Glenn:

might you try to write the tape and tell us what have happen? Please.