Media interchange switch for magnetic disk drives

A magnetic disk drive has a media interchange switch which interconnects the two head/disk drive assemblies with the two electronic systems in the drive. A manually operated switch on the operator panel operates a latching relay to one of two positions. Multiple pole, double throw relay contacts actuated by the latching relay connect spindle and head address signals, data signals, servo signals and other signals between either of the two head/disk assemblies and either of the two electronic systems. The sets of the switch contact poles are connected so that ground potential appears on switch contacts interposed between two active signal lines. In this manner, shielding is obtained with relays which otherwise have such low intercontact isolation that signal interference would be present.