A disk apparatus includes a DSP, and a DSP core of the DSP receives a feedback input from a pick-up, and generates a focus control pulse and a tracking control pulse. The controller server searches a user management file for user information corresponding to the ID number. Preferably, the label comprises a film base layer secured to the container, the grid pattern comprising an ink and varnish mixture printed over the film base layer, and a laminate top layer secured to the film base layer. Alternately, the correction signal may be combined with the first and second differential currents to reduce the offset.