Subject: Re: Who's accessing my disk?
To: Jukka Marin <>
From: Michael Eriksson <>
List: current-users
Date: 02/07/1999 19:55:43
In message <>
  Jukka Marin <> writes:
> Yes, I know what update is and why it does what it does.  What I didn't know
> was why anything was "flushed to disk" when no data were being written to any
> file.  The answer is that sync() updates the disk superblock timestamps
> even when no buffers are actually flushed to disk.  So, as far as I
> understand, using async mount is currently the only way to keep the disk
> sleeping.

No, it's inode meta-data (file atimes and device mtimes) that's being
flushed to disk. This is my /etc/apm/battery (see apm(8)):


mount -u -o noatime,nodevmtime /
mount -u -o noatime /usr
mount -u -o noatime /var
echo "atactl wd0 setstandby 5" > /etc/apm/atacfg
. /etc/apm/atacfg

This works great for me (disk only spins up "when it has to"). I
really don't want to run without update or with file systems mounted

Also check out

(Hmm, BTW. I've hacked apmd only to call /etc/apm/battery once for a
change of power mode. Before, it called /etc/apm/battery for each APM
event, which sucks on my Thinkpad 760 (one event per percent battery
used). Patches available on request (I will send-pr them sometime).)

Michael Eriksson <>