I see your point but I think your logic is flawed. In your first reply, you said, "the secondary cable is usually the one the dvd/cd is attached to, you can put both on one cable if it has two connectors on the cable." If a hard drive and a DVD/CD drive were on the same cable, he would still need to set master and slave settings. And, besides, he may have already had two optical drives on that channel.
What he could do, in this case, is temporarily disconnect any optical drives from the IDE2 connector and then connect the second hard drive to it. That way, no master/slave configuration issues.