Provided is a storage device that includes a first interface unit
configured to connect to an external apparatus, a second interface unit
configured to connect to a network, and a control unit which control the
storage device. The control unit determines whether the external
apparatus is connected to the first interface unit. The control unit
selects a first operating mode where the storage device is used by the
external apparatus and the second interface unit is disabled, if the
control units determines that the external apparatus is connected to the
first interface unit. The control unit selects a second operating mode
where the storage device operates as a file server and the second
interface is enabled, if the control unit determines that the external
apparatus is not connected to the first interface unit.