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Date:      Thu, 1 Feb 1996 18:42:40 +1030 (CST)
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        hackers@freebsd.org
Subject:   BSD slices in FAT filesystems...
Message-ID:  <199602010812.SAA23271@genesis.atrad.adelaide.edu.au>

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Ok, I'm being boring and trotting this one out for another round of comments.
The code for this is slowly taking shape, but I'm not getting as much time
to work on it as I'd have liked.  Any commentary will of course be 
appreciated.

At the end of dsinit() in diskslice_machdep.c (which as I understand it is
called once per disk), I walk the list of slices looking for bigdos
filesystems.

For each filesystem, I look for a directory called 'slabs.bsd'.  If the
directory exists, I look in it for files 'a'-'h', 'c' excluded.  If any
of these files are completely contiguous, I add their sector ranges to
a disklabel attached to the slice.

If after this, there's no 'b' partition assigned, I look for a Windows
swapfile and possibly add this.

I have some rudimentary tools for making these slabs as well.

As far as I can see, this gets around the overlapping-slices problem with
my earlier model, however I still have a few (annoying) questions 8)

How much of the disklabel structure is actually used?  For the hell of it, I
bulk-copy the label that's passed to dsinit(), but I'm sure this isn't
the best thing to do.  Are the p_frag and cpg/sgs values used?  I couldn't
follow their ufs/ffs usage down to be sure 8(

What should I do with the 'c' partition?  The disklabel is marked readonly
(for obvious reasons), so it's not likely to be useful for that.  I guess
I could just forget it, or maybe allow it to be assigned like the other
partitions.  Trying to make it cover all the other partitions would be 
stupid; I'm just not sure what other things may want to tinker with it...

-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
]] Genesis Software                     genesis@atrad.adelaide.edu.au   [[
]] High-speed data acquisition and      (GSM mobile) 0411-222-496       [[
]] realtime instrument control          (ph/fax)  +61-8-267-3039        [[
]] "wherever you go, there you are" - Buckaroo Banzai                   [[



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