2011 13" Macbook Pro: HDD starts up/down/up/down..

[virtual]

Had the MBP for about a week now.

The noise comes from the bottom right (I believe that is the location of the HDD) which sounds like a fan is coming on for 10 seconds, off for 10 seconds, on for 10 seconds, off for 10 seconds.

It's not a loud noise (note: not the clicking noise), but enough to be annoying when laying in bed whilst doing some surfing.

Does anyone know if this is normal, and if not what it could potentially be and mean?

Thanks!

Edit: It's a Hitachi 320GB HDD.

 

[virtual]

Nobody have any ideas? ):

 

[0983475]

have the same problem/annoying noises over here. MBP 2,7GHz, but a Toshiba 500 GB harddisk.Don't have any ideas either, so if anyone has any comment on this topic?! ^^