Moving the Macbook Pro with a sudden movement makes hard drive screech.

Question

Whenever I move my Macbook Pro from my lap to somewhere else I hear the hard drive make like a little teeny tire screech noise. I noticed this the time I was in my room in total silence when I put the Macbook down on the bed.
Its just a concern I have that I might wear out the hard drive faster this way since most of the time I'm moving the computer from place to place. Anyone else have the same concern?

Answer 1

The screech you hear is the drive quickly moving its read-write heads off the platters and onto a small ramp to prevent shock damage to the heads and platters.
The sudden motion sensor (SMS) does this in anticipation of a possible drop. This does not mean there is an actual danger of damage to the drive when this happens.
Nevertheless, I would avoid it if possible. It's an emergency head retract operation that can damage some drives over time. This may not be the case with the drives Apple is using, but we don't know for sure.
The SMS can be disabled as described here:
http://support.apple.com/kb/HT1934
But this will increase the chance of data loss in the event of a real drop.