crash dumps and slices (?)

[walt]

On Tue, 19 Sep 2006, Gergo Szakal wrote:

> Hello,
> If i set dumpdev to the slice (bad term?)...

Yes.  The dumpdev is usually set to be the swap
'partition'.  The word 'slice' describes one of the
areas of a hard disk which is specified in the DOS
'partition table'.  This ambiguity is disgusting,
at best.

In BSD-land, the partitions are defined only in the
BSD disklabel, where each BSD 'partition' bears a
letter [a-z], and the swap 'partition' by long
tradition is named 'b'.

For example, on my DragonFly machine:
# disklabel ad1s6 [my DF 'slice']
<snip irrelevant junk>
#        size   offset    fstype   [fsize bsize bps/cpg]
  a: 15739286  1048576    4.2BSD     2048 16384    89   # (Cyl.   65*- 1044*)
  b:  1048576        0      swap                        # (Cyl.    0 - 65*)
  c: 16787862        0    unused        0     0         # (Cyl.    0 - 1044*)

Thus, my DF swap 'partition' is named /dev/ad1s6b and the 'root' partition
is named /dev/ad1s6a.

The 'slice' ad1s6 is the second 'extended DOS partition' in the
'DOS Partition Table' which resides in sector 0 of the second physical
hard disk (/dev/ad1).

Very confusing!