"Much of the current documentation focuses on modifying
your kernel parameters and hdparm settings to reduce unnecessary
disk activity. In addition, extensive documentation is available
for changing your processor settings to maximize the benefits of
dynamic frequency scaling based on your current power source.
"This article provides tools and code to build on these
power-saving measures by monitoring your application-usage
patterns. Use the techniques presented here to change your power
settings based on the application in focus, user activity, and
general system performance"