Finding out which IDE chain my drives ar

Our desktops are finally transitioning from NT 4 sp3 to sp6a. I would like for our machines to be able to take advantage of the UDMA support that was introduced in SP5, but I don’t know if our machines are configured so that our HDD is alone on theprimary IDE chain, or if it shares it with the CDROM. Is there a way to find this information without having to open the case? Thanks