[comp.sys.sun] Recovering backup label information if original disk label corrupt?

malc@uunet.uu.net (Malcolm Carlock) (06/28/91)

We have a disk (HP 97549T) which was originally partitioned and labelled
"by hand" from within the 4.1.1 format program.  It currently contains
filesystems and data that the owner (not me, I make backups) would like to
recover.  The partition info was not recorded in /etc/format.dat nor was
it kept in written form.  We've been using the format program to try to
read the backup label information.  The format program says it's found
backup labels, but then says "Backup label claims different type", and
gives no further information (nor does it initialize format's partition
image with the information it does find.)

Apparently the ASCII disk type in the backup label is different from the
disk_type information in format.dat (this information was obtained from the
third-party vendor who supplied the disk, and is claimed to be correct for
this disk), and there doesn't seem to be any way of making format divulge
the information it's found in the backup label -- which is pretty darned
frustrating, considering that format must have seen SOMETHING in order
to make the comparison.  How about showing us what it was, so we can take
a guess at what needs to be changed in disk_info?

Trying various permutations of the disk name have been unsuccessful, and
after talking with Sun it doesn't appear that there's any way of making
format divulge further information about the backup labels it's finding.

Does anyone know how this backup label info can be recovered under these
circumstances?  Special calls to ioctl(), anything? (not that the raw device
can even be opened without a disk label...)

Please respond via email, and I will summarize to the net.

Thanks in advance.