On Mon, Sep 04, 2000 at 09:12:05AM +1100, Robert Elz wrote:
>     Date:        Sun, 3 Sep 2000 17:44:34 +0200
>     From:        Manuel Bouyer <bouyer@antioche.lip6.fr>
>     Message-ID:  <20000903174434.A517@antioche.eu.org>
> 
>   | with 8 partitons, wd0a has minor 0, wd0h minor 7 and wd1a minor 8
>   | (see the DISKUNIT, DISKPART and DISKMINOR macros). With 16 partitons,
>   | miror 8 becomes wd0i and wd1a has minor 16.
> 
> Only if the mapping from minor(dev) to partition remains the simple form
> that it currently takes (the low N bits).   It doesn't have to.  It would
> not be totally unreasonable to have the partition number taken from the
> low 3 bits of the minor dev, then skip (say) 10-12 bits for the device
> number, then use the remaining 5-7 bits for the rest of the partition number.
> That would allow between 256 and 1024 partitions/device, which is way
> more than can possibly fit in a label anyway (or be named using the XdNx
> naming scheme).

Sure, there are ways to handle this. But the consensus was that this was not
the rigth way of doing it, and I think it still has compat problems (there
will be, for ports which have already 16 partitions :)
The result of the discussion was that the rigth thing was to go to a new,
machine-independant sheme (we also have to change the disklabel to allow
more than 16 paritions because with only 16 parts, we'll have the problem
again soon).

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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