Don't bother wasting time deciphering their disklabel, its
only marginally interesting and is documented in their header
files.  Either look for the ffs magic number (0x00011954) in
the superblock or just trust me that NeXT puts a 160k byte
front porch on their disks and use

   dd bs=1k skip=160

To grab the ufs filesystem image off of the CD.

Darrin

Trevin Beattie <trevin@xmission.com> writes:
> This is cool!  It's much the same sort of layout I got from my 640MB
> optical disk formatted by NeXTSTEP.  And if it's truly a full ffs partition
> on CD, then it proves a theory I had that one could create a ffs file
> system with 2K sectors, burn it on a CD, and use it just like a regular disk.
> 
> Tell me, did you read this super block from sector 3?  That's where it was
> written on my optical disk.  Oh, wait -- I can just read it off my own copy
> of the NeXTSTEP 3.3 CD!
> 
> Hmmm... very interesting.  There are actually _multiple_ disk labels here,
> and except for the first one (on sector 0), they are not aligned on a
> sector boundary.  The cd_label_blkno field, which changes for each copy of
> the disk label (it's the block # of the label), is given in terms of
> 512-byte blocks, NOT cd_secsize (# of bytes per sector).
> 
> Moving on to the root partition 'a'... well, that's supposed to start on
> sector 0, but I don't see anything that resembles a super block... extra
> disk labels on sectors 3, 7, and 11... this looks like an aout header on
> sector 16... strings for a boot loader on sector 32... another boot loader
> on sector 48... Ah, here it is, on sector 84.  That's odd; I wonder where
> they came up with that number?
> 
> -----------------------
> Trevin Beattie          "Do not meddle in the affairs of wizards,
> trevin@xmission.com     for you are crunchy and good with ketchup."
>       {:->                                     --unknown