This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
It is needed for implementation details but very little of it is
needed for the interface. Include it in the few places that didn't
already include it.
Include <sys/ioccom.h> in <sys/disklabel.h> (as already in
<sys/diskslice.h>) so that all the disk-related headers are almost
self-sufficient.
- ignore the partition table if it is identical with the bogus one in
/usr/src/sys/i386/boot/biosboot/start.S. Honoring the bogus size
field was fatal. The error is detected but other compatibilty
cruft weakens the error handling too much for this case.
- weaken the partition entry checking to allow the following treatments
of C/H/S addresses when C should be >= 1024:
(1) allow C = 1023, H = max, S = max.
(2) allow C to be correct modulo 1024.
Other compatibilty cruft weakens the error handling to allow all
C/H/S addresses, but there too many errors were reported.
Improve error messages:
- print C/H/S addresses if relevant.
- distinguish primary partition table from extended partition tables.
- don't use diskerr() except for i/o errors.
Slice 0 is now for the first BSD slice. The first BSD slice is
the first DOSpartition with id 0xa5 or the whole disk if their
are no DOSpartitions (except the latter is not yet implemented).
Existing partitions on it work the same as in 2.0 except the
'd' partition is no longer special and partitions are relative
to the skice.
Slice 1 is now for the whole disk and gets a read-only label
describing the disk. Previously, slice 0 was for the whole disk
and there was no label on it.
Slices 2-31 are for DOSpartitions. Slice 0 is an alias for one
of these if there is a BSD slice. Previously, slices 1-31 were
for DOSpartitions.
diskslice_machdep.c:
Expand whole disk slice to include all DOSpartitions. More work
is required for >1024 cylinders and to rewrite the label iff the
driver is unsure about the geometry.
subr_diskslice.c:
New function dsisopen() to help handle media changes.
