External storage device, control device, external storage system, control method, program, and recording medium

An external storage device including first and second input/output units for performing input/output of information from/to an outside, a plurality of storage units connected between the first and second input/output units so that a transmission path of information forms a series connection, and a configuration control unit. The configuration control unit selects two adjacent units from the first input/output unit, each of the plurality of storage units, and the second input/output unit to set a boundary between the two units. Thus the configuration control unit causes the storage units located on a first input/output unit side of the boundary to communicate with the outside by using the first input/output unit and causes the storage units located on a second input/output unit side of the boundary to communicate with the outside by using the second input/output unit.