A call signaling protocol that uses simplified messaging to set up, confirm set up, tear down, and confirm tear down of a connection. A first gate electrode is formed on the first impurity doped region with a first gate insulation film interposed therebetween. The spindle is seated in a retaining means with a graduated lip around the perimeter. The non-volatile memory device can be configured to store device information at the predetermined address. Sample and hold circuits sample and hold the tracking error signal and the focus error signal at a timing delayed by the time corresponding to the delay time of each of the generation circuits, respectively.