Subject: Re: Another changer, another changer problem
To: None <current-users@netbsd.org>
From: Greg A. Woods <woods@most.weird.com>
List: current-users
Date: 10/05/1998 01:19:28
[ On Sun, October 4, 1998 at 21:08:52 (-0400), der Mouse wrote: ]
> Subject: Re: Another changer, another changer problem
>
> > How about we explain it this way:  If you count your partitions from
> > "one" (1), then there's a spare minor number for each ``unit'' (0).
> > I.e. one could simply assume there are 17 (or 23) slices per unit and
> > use the 0'th [or 17'th (or 23'rd) if you detest counting from one]
> > unit as the raw disk.
> 
> As far as I can tell, this is exactly what we've already got, except
> 
> - the number is 8 (or 16 on some ports), not 17 or 23 or whatever

The "17" would be to accommodate the 16 partitions currently available
on some ports (which would also clearly accommodate all those ports
using only 8 partitions too), and the 23 is to accommodate the
theoretical 22 maximum partitions that'll fit in DEV_BSIZE bytes (though
in theory that's a silly restriction in the bigger picture of things).

> - the distinguished partition is #2 (#3 on i386) [0-origin]

Which is just hysterical practice in action, not what I'm proposing.

> I don't see either one as a critical difference.
> 
> What am I missing?

The fact that the "#2" raw partition obliterates a partition table entry
and the "0'th" minor number that I'm proposing has nothing whatsoever to
do with any partition, or even the disk label.  *All* partition table
entries should be reserved *only* for the administrator, none need be
taken by the kernel or disk drivers.

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods@acm.org>      <robohack!woods>
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