Periodic CD Making Starting Noises

[gkp]

Every once in a while when I wake my MBP from sleep it makes a noise like I am inserting a cd/dvd. It stops after a few seconds. Same for when I start iMovie, everytime.
Anyone else have this happen? is it normal for a slot loading drive? I have not had this happen on my old powerbook.
?

 

[r.j.s]

It's normal, the drive is checking for a disc, that's all.