Storage device system

A storage device system in which migration of data from an existing storage device to a higher-standard storage device is unnecessary, and in which discarding of existing storage devices by the user can be prevented. A CHF 61 receives a Read Capacity command from a new-type storage device 25 (S 101 ). Using LDEV, LUN and other information tables, an LUN 87 is converted into a mapped LDEV (S 102 ). A check is performed to determine whether the LDEV emulation type is read-only, write-only, or read/write (S 103 ). If none of these, a check is performed to determine whether the emulation type is newly created (S 104 ). If newly created, the size of all storage areas of the LDEV are set as the Max LBA in a response to the new-type storage device 25 (S 105 ). If the result of S 103 is YES, the size of the user area in the LDEV is set as the Max LBA in a response to the new-type storage device 25 (S 106 ). If not newly created, processing proceeds to the processing of S 106.