Comment 633 for bug 59695

HOWTO fix this problem on Ubuntu 8.10:

An up-to-date Ubuntu 8.10 (in it's default state) includes fixes for this problem in it's "acpi-support" package. But they do not work because there's a small failure in the scripts.

Therefore you can correct these scripts manually (just like written in https://bugs.launchpad.net/ubuntu/+source/acpi-support/+bug/59695/comments/612 ) or you simply install the updated package including these fixes form Tom's PPA http://ppa.launchpad.net/thjaeger/ubuntu/pool/main/a/acpi-support/ .

And when you want those stuff also to function at the wakeup from suspend, you should just run
sudo ln -s /etc/acpi/resume.d/90-hdparm.sh /etc/pm/sleep.d/
in a terminal next to you.

It is just as easy as this. After done that you only need to plug off and in your AC to get the fixes working. BTW they are designed to work exclusively at AC, as they would otherwise deactivate the shock protection of your laptop's harddrive when running on battery.