I just remembered this topic, and came back for a look. No replies! Shockers. Time to rectify.....
I'm of the belief that drives should only share channels with devices of the same type. Optical drives on one channel, hard drives on the other. Now, I'm buggered if I can remember any benchmarks or official tests that prove what's best, and I'm buggered if I can be bothered looking anything up at this hour of the night.
That said, my "belief" stems from the (possibly horribly incorrect) knowledge that:
- Optical drives utilise a different transfer protocol from hard drives, so any sharing between the two could potentially slow things down with two different protocols in action.
- Two hard drives on one ATA100/133 channel have plenty of bandwidth to bandy around with - transfer rates rarely hit more than 30-40Mb/s.