I've got a MO640 disk and a sparc IPX.  When I tried to mount the disk I
got an error saying no disklabel.  So I edited the disklabel and tried
to write it back to the disk.  I've used disklabel -i to create the
disklabel.  I was having problems with it so I decided to just do a
single partition on it.  When I tell disklabel to write the lebel to
disk I get the following error:
    disklabel: ioctl DIOCWINFO: Label magic number or checksum is wrong!

    (or kernel is out of date?)

How do I fix this?
    John