"Part of proper power management is the ability to put your laptop to sleep. ACPI sleep is defined as a state where the system is still technically powered on, but the screen and hard disk are powered down and the computer is using just enough power to keep the contents of RAM alive. The Ubuntu development team has devoted an immense amount of effort toward getting ACPI power management working properly. As it stands, Ubuntu is power-management-friendly right out of the box, thanks to the recent addition of the gnome-power-manager package. It turns out there's not much required to get most modern laptops to sleep and wake up correctly.
"The Dapper Drake release of Ubuntu Linux includes the new gnome-power-manager package, which enables ACPI sleep much like the system-tray power applet in Windows. Finally, sleep 'just works' in Linux..."
