Information processing apparatus and method and information recording medium

A navigation equipment (S) for performing the navigation processing by the use of the information from a plurality of hard disk recording and reproducing units which is provided with: a hard disk recording and reproducing unit (13) including a hard disk, in which the map information or the like to be used for the navigation processing and be planned to be updated and the additional information corresponding to the navigation processing by the use of this map information or the like are recorded; and a system controlling unit (16), which detects whether a second hard disk recording and reproducing unit (13a) is connected or not and releases an area, in which the map information or the like in the hard disk recording and reproducing unit (13) is recorded, if the connection of the present second hard disk recording and reproducing unit (13a) is detected.