[rescue] reading old unix disks from Linux

Mike Spooner mikes at aalin.co.uk
Fri Apr 26 06:02:56 CDT 2019

Caution needed - there isn't a single "UFS", there are multiple minor variations on a theme; including ACL formats, large-file on-disk metadata structures, capability flags, et al et al et al et al.

On Fri, Apr 26, 2019 at 10:59 AM +0100, "Jonathan Katz" <jon at jonworld.com> 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.

On Fri, Apr 26, 2019 at 10:47 AM Andrew K. Bressen <
akb+sites.sunhelp at mirror.to> wrote:

> Hi!
> I have old SCSI drives I'm trying to read, and I'm running into a number
> of different issues I'd welcome feedback on.
> I've got drives from PCs, Macs, Suns, and DEC machines, and I'm using a
> 32 bit linux box (3.x kernel) to read them all. One thing I'm
> wondering is if I'd have fewer problems booting off a FreeBSD or NetBSD
> liveCD.
> Mostly it's gone well (no sw problems with PC or Mac disks!), but here
> are some of the fiddly things I've been dealing with on the DECstation
> and Sun disks and would love help/suggestions on.
> Software stack:
> (1)
> 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
> on a disk with as many as 7 partitions.
> How do I see what the partitions actually are?
> because...
> (2)
> Mounting is weird.
> Often, a disk will have overlapping partitions that will mount.
> For example, on one disk, I have 7 partitions.
> Mounting partitions 1 and 3 looks the same at the mount point,
> as do partitions 4 and 7. (3 seems to be the entire disk,
> which is of course normal for old unixes).
> Except with the filesystem mounted via sdc1, some files will throw
> i/o errors if I try to read them, but when mounted via sdc3,
> the same files won't.
> (3)
> Some stuff won't mount.
> So, I have disks of unknown partitions. Some of them are probably swap.
> How do I tell?
> 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?
> (4)
> Some stuff is empty.
> In a few cases, I've mounted partitions and seen only a lost+found
> directory that's empty. And dated sometime in the 1990s. But if I
> run strings(1) on the dd files of the raw partitions, I see tons
> of stuff there. So, am I seeing the remains of deleted files, or
> is the UFS driver buggy or having a poor interaction with the kernel's
> determination of partitions? Is there an undelete tool for antique UFS?
> AND THEN there's hardware questions, but
> I'll maybe ask those in a different message...
>   --thanks if you've read this far!
>   --andrew
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