Leaving the power management enabled for your hard disk might shorten its life considerably. To give you an idea about it read this entry in a thread on the topic:
http://lists.debian.org/debian-powerpc/2008/10/msg00008.html
To see whether power management is enabled for your disk, you can enter something like this:
hdparm -I /dev/hda | grep -i “power management”
On Debian Linux one might want write an entry like this to /etc/hdparm.conf, if /dev/hda is the disk you want to switch off the Power Management for:
### START excerpt /etc/hdparm.conf ###
apm = 255
/dev/hda {
}
### END excerpt /etc/hdparm.conf ###
Additionally I have this in /etc/default/hdparm:
### START excerpt /etc/default/hdparm ###
harddisks=”/dev/hda”
hdparm_opts=”-B255″
### END excerpt /etc/default/hdparm ###
A script like the one below might be necessary in /etc/power/scripts.d/, if you have pbbuttonsd running, to make sure the hdparm values are re-set after resuming the machine from some sleep mode:
/etc/power/scripts.d/hdresume:
### START /etc/power/scripts.d/hdresume ###
#!/bin/sh
# name : hdresume
# Exit silently if package is no longer installed
[ -x /etc/init.d/hdparm ] || exit 0
/etc/init.d/hdparm reload
### END /etc/power/scripts.d/hdresume ###
Link to the script from /etc/power/resume.d/:
# cd /etc/power/resume.d/
# ln -s /etc/power/scripts.d/hdresume .
Note the dot at the end of the last line …
Oh, and the laptop-mode-tools package is not installed here.