Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 12 Oct 1996 16:47:21 -0400 (EDT)
From:      Barry Masterson <jbarrm@panix.com>
To:        Freebsd-questions <questions@freebsd.org>
Subject:   Cylinders & heads: dmesg VS fdisk
Message-ID:  <Pine.BSF.3.91.961012163320.476A-100000@jbarrm.dialup.access.net>

next in thread | raw e-mail | index | archive | help
When I run 'dmesg' & 'fdisk', the values for heads & cylinders are
different for the same disk:

[dmesg]
wdc0: unit 0 (wd0): <QUANTUM FIREBALL1080A>
wd0: 1039MB (2128896 sectors), 2112 cyls, 16 heads, 63 S/T, 512 B/S
                               ^^^^^^^^^  ^^^^^^^^
[fdisk]
******* Working on device /dev/rwd0 *******
parameters extracted from in-core disklabel are:
cylinders=528 heads=64 sectors/track=63 (4032 blks/cyl)
^^^^^^^^^^^^^ ^^^^^^^^

My question is; Why is there a difference in cylinders, & heads on wd0 ;
why would dmesg & fdisk show different values?


I'm adding a second disk. dmesg reports the following, which corresponds
with the manufacturers specs:

[dmesg]
wdc1: unit 0 (wd2): <QUANTUM LIGHTNING 540A>
wd2: 516MB (1057280 sectors), 1120 cyls, 16 heads, 59 S/T, 512 B/S

I ran 'fdisk -i' on the second disk, and entered what I believe are 
the correct values, which fdisk reports as follows:

[fdisk]
******* Working on device /dev/rwd2 *******
parameters extracted from in-core disklabel are:
cylinders=1120 heads=16 sectors/track=59 (944 blks/cyl)

Here the cylinder & head values are the same.  Is there some calculation 
I'm missing when I'm in fdisk?  Or, is this how it should look; dmesg and
fdisk agree in cylinder & head values?


Thank you

Barry Masterson
jbarrm@panix.com

>--->--->--->--->--->
  FreeBSD   2.1.5-R
<---<---<---<---<---<




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.3.91.961012163320.476A-100000>