PS3 froze, Then I shut it off, and it beeped about 2 or 3 times?

I was Playing U3 Beta, and I've noticed when I leave the U3 beta, It Freezes and I have no other choice but to shut off my PS3! Though when I shut my PS3 off, it beeps 2 or 3 times, then it shuts off. Just wondering if this is okay. I've read that it's just forcing to shut off due to it freezing!???