When I put a music CD in the drive, to rip off the songs, the drive started to spin as usual. However, it also started to make a strange loud, buzzing sound. What I want to know is:

1. What the sound means, obviously

2. If it's okay to put the disc in the drive, or if that will somehow damage it.

I only left the disc in the drive a few seconds after the noise began, and checked it briefly after. Still, I'd like to be sure.