An information storage device (10) includes a cartridge (14) removably inserted into a cradle (13) that has a drive module (18) releasably coupled to an interface module (17). A drive electronics circuit (71) in the drive module is coupled to a hard disk drive mechanism (56) in the cartridge, and is coupled through a bus switch (131) and a bus (122) to a bridge circuit (111) in the interface module. An auxiliary circuit (76) in the drive module is coupled to the bus, is controlled by the bridge circuit, operates the bus switch, and handles considerations relating to removability of the cartridge. The interface module is one of several interchangable interface modules which each have a different bridge circuit to interface the bus to a respective different communication protocol.
