Manual warewashing in common food service locations is typically performed in a multicompartment sink within three or more basins. A disk device has an operating mode ideal for recording and reproduction of motion image and audio data requiring real-time continuity by limiting the time needed for error processing, and the host incorporating the disk device can easily monitor the real-time continuity. This enables effective correction of chromatic aberrations even in the case of systems that are difficult to correct chromatically. An upper surface of the first rib extends continuously from the one end to the other end and is discontinued at the other end, the other end of the upper surface of the first rib being separated from the exterior covering. Data is retrieved from the cells by illuminating the storage material with the reference beam to produce a reconstructed data beam.