all computers ( unless really ancient ie over 20 yrs old )have two IDE ports ( these connect to your Hard-drives and your CD/DVD drives.)
each port can have 2 devices ( drives connected ) as long as each port has 1 device set as master and the other device as slave so you can have upto 4 devices ( hard drives cd drives dvd drives ) or a mixture of them. I have 3 harddrives and a DVD writer, my friend has 2 harddrives and a DVD rom and a DVD writer. you get 1 cable per IDE device it will connect to 2 devices just ensure 1 is set to master and the other is set to slave.
Gary, January 2006