A windup window shade comprises a preassembled unit, consisting at least of the windup shaft, the associated seating elements and a frame tubing connecting the seating elements. The integrated circuit including an interface between the physical coding and media access control circuitry, and an equalization control circuit which is external to the physical coding circuitry and which is configured to perform the dynamic transmit equalization using said interface. Combining the optical system for information recording and reproduction with the slider reduces the size of the optical head compared with an optical head adopting a slider and a large optical system which are separated from each other. The displacement of the optical pickup 114 to the inner peripheral position on a minidisk or a compact disk is detected based on the internal state of the switch 132 and the flow direction of current supplied to the motor 116 for driving the movable body 115.