Is it possible to have two master EIDE or IDE drives?
Two or more master hard drives, CD-ROM drives, or different EIDE/IDE disk drives can be in one computer. However, you can only have one master per channel or per cable. All other drives on the same cable must have their jumpers set to slave or cable select.
Computers with an EIDE/IDE controller have two connection points (channels), which means two different masters and two slaves for a total of four different drives. In the picture below, the primary IDE channel could have one master drive and the secondary IDE channel could have one master drive.