[rescue] reading old unix disks from Linux

[Michael Parson]

On Fri, 26 Apr 2019, Andrew K. Bressen 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.

<snip>

The only experience I have with anything like this is mounting
filesytems out of a dd copy of a Solaris 2.5.1/sparc disk I made of the
disk that came with my Tadpole SparcBook 3gx.

Here are the notes I took:

-----
To mount the whole file (under Linux):

sudo mount -t ufs -o loop,ro,offset=458752000 ./solaris-2.5.1-Tadpole.img /mnt/sbook
sudo mount -t ufs -o loop,ro ./solaris-2.5.1-Tadpole.img /mnt/sbook/usr

Where we got that offset:

$ fdisk -l ./solaris-2.5.1-Tadpole.img

Disk ./solaris-2.5.1-Tadpole.img (Sun disk label): 1 heads, 640 sectors, 1531 cylinders
Units = cylinders of 640 * 512 bytes

                       Device Flag    Start       End    Blocks   Id
System
./solaris-2.5.1-Tadpole.img1   r         0      1400    448000    4 SunOS usr
./solaris-2.5.1-Tadpole.img2   r      1400      1531     41920    2 SunOS root
./solaris-2.5.1-Tadpole.img3  ur      1400      1531     41920    0 Empty
./solaris-2.5.1-Tadpole.img4   r      1400      1531     41920    2 SunOS root
./solaris-2.5.1-Tadpole.img5   r      1400      1531     41920    2 SunOS root
./solaris-2.5.1-Tadpole.img6  ur      1400      1531     41920    0 Empty

$ dc
448000
512 *
2 * p
458752000

-----

Just tried it again on my Fedora 29 laptop and it still (mostly) works.

$ ls -l /mnt/sbook/
total 58
drwxr-xr-x  2 root   wheel    512 Jan  8  1996 a
lrwxrwxrwx  1 root   bin        9 Jan  8  1996 bin -> ./usr/bin
drwxr-xr-x  3 root   wheel    512 Jan  8  1996 cdrom
drwxrwxr-x 10 root   sys      512 Jan  8  1996 dev
drwxrwxr-x  3 root   sys      512 Jan  8  1996 devices
drwxrwxr-x 21 root   sys     2560 Jan  8  1996 etc
drwxrwxr-x  4 root   sys      512 Jan  8  1996 export
drwxrwxr-x  2 root   sys      512 Jan  8  1996 home
drwxr-xr-x  9 root   sys      512 Jan  8  1996 kernel
drwxrwxr-x  2 daemon daemon   512 Jan  8  1996 kvm
lrwxrwxrwx  1 root   bin        9 Jan  8  1996 lib -> ./usr/lib
drwx------  2 root   root    8192 Jan  8  1996 lost+found
drwxrwxr-x  2 root   sys      512 Jan  8  1996 mnt
lrwxrwxrwx  1 root   bin       41 Jan  8  1996 opt -> ./cdrom/export/exec/sparc.Solaris_2.5/opt
drwxr-xr-x  8 root   sys     1536 Feb  6  1996 platform
drwxr-xr-x  2 root   sys      512 Jan  8  1996 proc
-rw-r--r--  1 root   bin        0 Jan  8  1996 reconfigure
-rw-r--r--  1 root   wheel  28672 Jan  8  1996 root.proto
drwxrwxr-x  2 root   sys     1024 May 13  1996 sbin
drwxrwxrwt  4 adm    sys      512 Jan  8  1996 tmp
lrwxrwxrwx  1 root   bin       37 Jan  8  1996 usr -> ./cdrom/export/exec/sparc.Solaris_2.5
lrwxrwxrwx  1 root   bin       15 Jan  8  1996 var -> ../tmp/root/var

$ df /mnt/sbook/
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/loop0         39023 22191     12930  64% /mnt/sbook

It won't let me do the second mount, complains that there is an
overlapping loop device for the specified file.  Still should good
enough for pulling stuff out of the image if needed.

HTH.

-- 
Michael Parson
Pflugerville, TX