The present invention claims and discloses an information processor comprising: an auxiliary storing unit that has at least one and preferably two auxiliary storage devices in which at least three distributable virtual disks are formed so as to be distributed; a disk array control unit that controls the at least three distributable virtual disks that designate one of disk control modes; a CB storing unit that stores a control block in each virtual disk that includes but is not limited to first designation information for designating the disk control mode and second designation information for designating an auxiliary storage; and a device driver unit that generates control information of the disk array control unit including but not limited to the first designation information and the second designation information and that transmits the control information to the disk array control unit based on a request for accessing any of the at least three distributable virtual disks and a control block corresponding to the requested virtual disk.