Depends on what interface (if that is the word) the drives are.

S-ATA drives I have heard to be faster, but can only have one device per channel. Hence HD on #1 DVD on #2 DVD2 on #3
EIDE drives can have master/slave on a channel but IMHO seem to be a bit slower.

Conclusion: If your motherboard has SATA use it, else EDIE the HD as a master on #1 and DVD as the slave on #1, then the other DVD seperate - just like you heard!

I dont know 'what it does to the computer' as they are drives, they are designed for computers, so I would assume that they wont do anything to the computer. The only 'bad' thing could be getting the jumpers wrong!

If they are are standard PATA drives (IDE), then I would recommend that you do not put an optical drive and a hard drive on the same channel. They use different transfer protocols and so performance would be lower as a result. Make the hard drive master on channel #1 and the DVD burner master on channel #2 with the DVD-ROM as a slave.

SATA optical drives aren't very common at the moment.

Trying to hook up a Pioneer DVD Multi-Recorder, but I'm having some probs. The first time, my computer kept restarting and error reporting when you turned it on. The second time, both me D: and E: were running at the same time. I don't understand the Master and Slave concept. Could someone please explain it to me so I will know how to hook up my hardware? Thanks.

Please start your own thread to avoid confusion.

Modern computers don't care what device is on what channel.
The only caveat I know of is that data transfer is faster between devices on different channels.

The original setup is perfect for older computers and if you want to burn at high speeds. The reason is that if you want to burn, it is better to maintain a steady stream of data to the burner so that the burning process never stops. Reading data into memory using the same channel as the one writing it out is a risk.

Since your readonly drive as well as your hard disk are on #1 and your burner on #2 there is no risk at all.