Subject: Re: > 1T filesystems, disklabels, etc
To: None <>
From: Ignatios Souvatzis <>
List: tech-kern
Date: 12/15/2002 11:38:00
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On Sat, Dec 14, 2002 at 11:47:07PM -0800, Bill Studenmund wrote:
> I think we can get what everyone wants with something more of an
> intermediate step. Here's its proposal:

Which I won't copy here. However, it is possible in your scheme (and in=20
the wedge scheme) to find the same partition twice - what happens then?

Example: a MO medium with mbr + NetBSD label to be usable on a i386 and=20
with an RDB structure to be usable on an Amiga. Yes, this is perfectly=20

Now, if the PC doesn't know the RDB scheme, and the Amiga doesn't know the
PC scheme, all is well - but if they (or one of them) know both, you'll get

Do we want to avoid this? (e.g., if the same partition is offered
by a later scheme, it is ignored)

Do we want to make avoiding it switchable?

I think we want to avoid (undetected) duplication normally, as access to=20
a partition denies other accesses to a partition, at least at some
securelevels and for some types of accesses.
> c) amigaPart. Grabs like 16 partitions (I think that's an ok #) and fills
> them in like now.

That's what the current code does anyway, and I think the number is ok, too.
Note that conceptually, the RDSK block just points to a linked list of
PART blocks, with no upper limit on the number of partitions (other than
the number of blocks in the first N blocks of the disk, with N only
_guaranteed_ to be < the disk size).
> d) sun disklabel (if it is different at this level), grabs 8 partitions
> and reads from the sun disklabel.

Oh - is this a reference to the duplication problem I mentioned above?


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