Thanks for your replies.
I am trying to get Redhat installed on the second drive so I can have a proper play around with it. Now that the second drive is formatted and set as slave on the primary IDE channel using usual 40wire IDE cables, how can I tell the Redhat installation that I want to install Linux on the slave drive?
This seems impossible to work out in fdisk and I have info on the master drive that I don't want to lose so haven't been playing around with it too much.
Thanks!