How? When your ubuntu laptop is running on battery, the disk heads are parked as part of the power saving strategy. When the disk needs to be accessed, the heads are unparked. Apparently this can only happen about 600000 times before a disk becomes likely to fail. This is all well and good, however the Feisty and Gusty releases of Ubuntu do this up to 4 times per minute, which is _bad_, considering that kind of frequency gives your hard disk a life expectancy of 104 days!
This problem only occurs when your laptop is running on battery. The way to solve it is (replace sda with your hard disk device):
sudo hdparm -B 255 /dev/sdawhich turns off the aggressive power management features of your hard drive.
If you want to check how much life there is left in your hard disk:
sudo smartctl -d ata -a /dev/sda | grep Load_Cycle_CountMy laptop has clocked up 300000 cycles... which is amazing (in a bad way!), considering it is rarely unplugged.
Update: I've just discovered this is old news. I don't read slashdot anymore... :-) Shame there hasn't been a fix yet.
Update: According to an Ubuntu Dev, Ubuntu does not alter hard disk settings. So, it would appear that aggressive power management is not the problem. The problem is something is writing to the disk too frequently, which will unpark the disk heads. This is still an Ubuntu issue IMO.