Western Digital drives with NO slave drive on the same cable (another harddrive or cdrom type) requires NO jumper to be the Master. There is a jumper given to you that is in a sideways position basically 'parked' in a storage spot in case you should need it later.

Either leave the jumper off completely and use the end of the gray cable to hook it to, or jumper it as Cable Select (CS) and still use the end of the gray cable for the connection. If you use Cable Select, and decide later to add another harddrive as a slave or use another cdrom device as the slave, you would only have to jumper those other devices as Cable Select as well and use the center connector and you won't ever have to mess with the Western Digital jumper at all.

TONI