Windows 7 fails to power down idle disks, Fedora 14 works

My PC has two Samsung SpinPoint F3 500GB drives. The first disk contains Fedora 14 and the second disk has Windows 7.

When in Windows 7 I have no need for the Fedora 14 disk to be powered. Likewise, when in Fedora 14 I have no need for the Windows 7 disk to be powered.

So why not take advantage of power management and set idle disks to power off / spin down?

Great idea!

But this is where Windows 7 fails.

After a while Windows 7 will power down my idle (Fedora 14) disk but then it will randomly power the disk back up. This process would then repeat, an endless cycle of power down, power up, power down, power up....

Why does Windows 7 feel the need to poll my idle disk and wake it up?

Not only is this behaviour irritating but it undermines the idea of spinning down idle disks to save power.

Fedora 14 on the other hand spins down my idle (Windows 7) disk perfectly and does not randomly power the drive back up again unless I intentionally access the drive.

This therefore means with Linux I can have a greener PC and play an active part in saving the planet.

As measured with a mains power meter,  spinning down my idle disk reduced my PC's power consumption by an incredible 5 Watts.

Lower your carbon footprint and use Linux - the environmentally friendly operating system