When 2 drives are connected to the same data cable connected to an ide?

This is quite normal. IDE stands for Intergrated Drive Electronics. It basically means that most of the drive controller electronics are on the disk drive itself. You can connect 2 drives to one cable. One will be set as the master drive and the other will be set as the slave. The master drive then controls itself and the slave drive. The setting for slave/master is normally done by small connectors joining a pair of pins together called jumpers.