Abstract: The write cache control unit stores data in the buffer memory in response to a write command from a higher-level apparatus to respond a normal ending of the command, and then writes the data in the buffer memory on the disk medium. The vibratory environment measuring unit measures an environment under which a vibration is applied to the apparatus. When an abnormal vibratory environment under which writing on the disk medium likely fails is determined from a measured environment by the vibratory environment measuring unit, the vibration countermeasure processing unit disables the write cache control unit, and if the write cache data remains in the buffer memory at that time, writes the data in the temporary storage area, and if the abnormal vibratory environment is not determined, writes back the data to the original position on the disk medium.

Abstract: An upper-level equipment download firmware to a peripheral equipment while information having been set from the upper-level equipment is inherited after downloading. The peripheral equipment includes a controller for controlling the peripheral equipment through the execution of firmware and nonvolatile memories for storing information for the controller. The controller receives the firmware from upper-level equipment, and preserves in the nonvolatile memories the information set from the upper-level equipment to the peripheral equipment. At the time of initializing the peripheral equipment after receiving the firmware, the controller reads out the set information preserved in the nonvolatile memories, and resets the set information to the peripheral equipment.