I'll double check, but I don't believe they are. I have two Hard drives, a 120 gig main and 320 backup, as Primary master and slave. The CD rom drive is secondary master.
I have to confess, I didn't actually KNOW the CD rom was unplugged until recently. I had just forgotten to plug it back the last time I assembled it, and I never use CDs so I never noticed for years. Is it possible the Hard drives and CD rom drive were somehow scrambled in the process? I have a feeling the CD rom USED to be the primary master, but I'm not sure.