[rescue] reading old unix disks from Linux

[Mike Meredith]

On Fri, 26 Apr 2019 10:58:48 +0100, Jonathan Katz wrote:
> I'm thinking it would be easier with a BSD, as they are native to
> using UFS and understanding BSD disklabels, instead of the MBR stuff
> Linux has traditionally relied upon.

Actually Linux is quite well featured when it comes to dealing with
'foreign' disk labels. Not to say that *BSD wouldn't also work, but
Linux should be fine.

> On Fri, Apr 26, 2019 at 10:47 AM Andrew K. Bressen <
> akb+sites.sunhelp at mirror.to> wrote:
> > Linux often will see a drive as multiple partitions,
> > like sdc1 sdc2 sdc3 sdc4, but no linux partion tool
> > I've found shows me what the boundaries actually are,
> > for example parted might say
> >   Number  Start  End    Size   File system  Flags
> >    1      0.00B  105MB  105MB  sun-ufs

Er ... doesn't that show what the boundaries are?

> > Often, a disk will have overlapping partitions that will mount.

That's not uncommon with traditional Unix disk labels.

> > Some of them are labeled as SunOS (possibly as old as 3.5) and
> > running strings on them that looks believable, but they refuse to
> > mount (error is "wrong fs type, bad option, bad superblock
> > on /dev/loop0, missing codepage or helper program, or other error")
> > and the ufstype options don't help. What next?

I'd start by making an image of the entire disk, and then exhaustively
trying each 'partition' in turn trying to copy the entire filesystem
across. Something like (off the top of my head, not tested, and
needs to be modified for disk image files) :-

for slice in sdX*
do
  mount -t ufs -o ro,old ${slice} /mnt
  if [ $? -eq 0 ]
  then
    mkdir /var/tmp/$slice
    rsync -arv /mnt /var/tmp/${slice}
  else
    echo Failed for ${slice}
  fi
done

You may have to replace "old" with one of 44bsd, sun, sunx86, hp,
nextstep, openstep.

--
Mike Meredith (http://zonky.org/)
Any civilization where the main symbol of religious veneration is a tool
of execution is a bad place to have children.
  -- Charles Stross

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