Out of curiosity I tried hooking up a CD drive to my PCI-to-IDE controllers to see if they would boot. They did not.

I only have two adapters; a Silicon Image SiI0680A and a Promise PDC20269. Both controllers see the drive but won't boot to it. They will boot to any attached disk drive just fine.

One interesting thing I discovered while testing is that the Promise controller will not allow the system to boot at all with a POST code error of 0D0C if the drive is set to Cable Select and there is no disk drive connected elsewhere on the controller or an onboard IDE channel.