greywolf@defender.VAS.viewlogic.com writes:

  > So, what would be the ramification of those ports supporting a dual-disklabel
  > scheme?  Surely there's some blank space at the head of the disk where there
  > is room to write a BSD-style disk label...?

There is actually some unused space in the bsd disk label big enough
to take a Sun disk label. It is not at the right location, however,
the bsd disk label code goes walking through the first block or so looking
for the correct magic number, so it will in fact support a disk label
offset by an extra 64 bytes which puts its unused area over the SunOs
disk label. Then you need to adjust the checksum to take account of
the presence of the Sun label.

I actually do this so I can share a disk between computers. I have a
special program to create the combined label.

One problem is that the sun label expresses things in different units
to the bsd label (ie cylinders instead of blocks). Also the sparing
etc can be different.

If the sun label is only used to boot, you have a bit more freedom.
You only need the a partition to start at the same location in both
labels. It doesn't even have be the same size. All that matters is
that installboot can find the blocks of the kernel properly.

I think this is doable. How much it buys you is another question...

Ian