All the jumpers in my B&W are set to Cable Select. OpenFirmware takes care of mapping the drives at boot up. The only caveat is if you can't boot from a drive if you install it on the secondary channel (the one with the optical drive). If your B&W has the stock ATA cables in it, you might need to get a double-drive cable, as the cable in my machine for the hard drive only has two connectors (HD, logic board) with no provision for adding another drive.