Abstract: When a removable medium is inserted, a medium information managing unit of a storing apparatus reads out medium information in a predetermined area and analyzes, thereby forming medium management information including access formats such as ROM, RAM, security in which a password is needed, and the like in correspondence to a plurality of partitions constructing a virtual medium by dividing an area in the medium into a plurality of data areas. When an input/output request is received from an upper apparatus, a command processing unit recognizes the access format of the target partition from the medium management information and executes a process corresponding to the access format.