Following up to myself...

Searching the mailing list archives a little better, I found this
post from 2000:

http://mail-index.netbsd.org/port-macppc/2000/12/15/0003.html

...which indicates that the problem is the mixed-endianness of the
disklabel.  That is, I couldn't read the disklabel from an alpha on
a macppc because the former is little-endian and the latter big-endian.
Since this was only a 2G disk, I tried an experiment:  using
dd, I made an image of the disk to an NFS file system mounted
from a netbsd/i386 box.  Using vnconfig, I configured vnd0 to point at
this file.  On the i386 box (which is _also_ little-endian), I was
able to read the disklabel of vnd0 just fine, and to mount the partitions.
My data has now been recovered.

This begs the question:  what's the point of endian-independent FFS
support if I can't actually read the disklabel cross-endian?  How
difficult would cross-endian disklabel support be to add?

+j

On Mon, Apr 19, 2004 at 08:39:59PM -0700, Jeff Rizzo wrote:
> OK, I've not had a good afternoon.  :)  After installing a new disk in
> my alpha (which was running 1.6.1), somehow the power supply either
> fried or decided that it was a good time to give up the ghost.
> Argh.
> 
> I can live without the machine, but I'd *really* like to get the data
> off the disks if I can.  (Nothing I can't recreate, but I'd rather not
> have to).  However, the only other machine I have at the moment with
> a 50-pin scsi interface (at least the only one I can take down to install
> this disk) is a box running 1.6_RC2/macppc.
> 
> The drive is seen as sd2, but apparently alpha and macppc put their 
> disklabels in different places, because it doesn't see the label.
> I have FFS_EI compiled into the kernel, so I assume I'll be able
> to read the partitions once I can find them, despite the endianness
> differences.
> 
> Anyone got a suggestion for how to proceed?
> 
> Thanks!
> 
> +j
> 
> -- 
> Jeff Rizzo                                         http://boogers.sf.ca.us/~riz

-- 
Jeff Rizzo                                         http://boogers.sf.ca.us/~riz