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Date: Tue, 24 Jan 1995 17:03:24 -0500
From: L Jonas Olsson <ljo@amcell2.caisr.cwru.edu>
Message-Id: <199501242203.RAA08717@amcell2.caisr.cwru.edu>
To: phk@ref.tfs.com
CC: terry@cs.weber.edu, bde@zeta.org.au, freebsd-hackers@freefall.cdrom.com,
        kuku@gilberto.physik.rwth-aachen.de
In-reply-to: <199501242138.NAA22208@ref.tfs.com> (message from Poul-Henning Kamp on Tue, 24 Jan 1995 13:38:13 -0800 (PST))
Subject: Re: disklabel (1.1.5.1), partitions
Reply-to: ljo@po.cwru.edu
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   From: Poul-Henning Kamp <phk@ref.tfs.com>
   Date: Tue, 24 Jan 1995 13:38:13 -0800 (PST)
   Cc: bde@zeta.org.au, freebsd-hackers@freefall.cdrom.com,
	   kuku@gilberto.physik.rwth-aachen.de
   Content-Type: text
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   Sender: hackers-owner@FreeBSD.org
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   <...>

   The problem is that you will get newfs into some strange corners if you
   report for instance 255 heads, as most of the ">1GB" stuff does...

 It is possible to use this geometry. I have one here (aic6360
controller on ZEOS MB):

dumpfs /dev/sd0a gives:
magic   11954   format  dynamic time    Mon Jan 11 22:26:27 1988
nbfree  637     ndir    58      nifree  7206    nffree  2
ncg     1       ncyl    2       size    4016    blocks  3761
bsize   8192    shift   13      mask    0xffffe000
fsize   4096    shift   12      mask    0xfffff000
frag    2       shift   1       fsbtodb 3
cpg     16      bpg     16065   fpg     32130   ipg     7872
minfree 10%     optim   time    maxcontig 1     maxbpg  2048
rotdelay 4ms    headswitch 0us  trackseek 0us   rps     60
ntrak   255     nsect   63      npsect  63      spc     16065
trackskew 0     interleave 1
nindir  2048    inopb   64      nspf    8
sblkno  4       cblkno  6       iblkno  8       dblkno  254
sbsize  4096    cgsize  8192    cgoffset 8      cgmask  0xffffff00
csaddr  254     cssize  4096    shift   9       mask    0xfffffe00
cgrotor 0       fmod    0       ronly   0

 Note that fragment size (fsize) has to be 4096 to get past
newfs. This machine is also not very stable, so perhaps the 255 head
geometry should be avoided. This is with FreeBSD 1.1.

Jonas