A disk drive apparatus mounting socket includes a socket portion which supports a disk drive apparatus, a lead portion which is connected to the disk drive apparatus supported by the socket portion, and a terminal unit which is electrically connected to the lead portion and to circuits on a board. A disk drive apparatus, which is connectable to an information processing unit, includes a connecting unit which connects the disk drive apparatus to the information processing unit, and an interface unit which controls the disk drive apparatus in response to a control signal, a data bus signal, and an address bus signal which are generated by the information processing unit and are inputted to the disk drive apparatus from the information processing unit via the connecting unit.