New Hitachi Travelstar 5K100 firmware enables Device-initiated interface power management (DIPM)

You'll want to grab the updated firmware set for Thinkpads here.

Many other hard drive models are covered, but I only have a 5K100 to test the firmware with. Other updated firmware might enable DIPM too.

Why is this important? Because of this, with DIPM, Vista can manage the power of the hard drive much more efficiently. I doubt it will extend battery life by 20%, but every little bit counts when you are on a plane.

I've written about DIPM and Host-initiated Power Management (HIPM) in the past with links to articles if you want to learn more about it.