A disk recording andor reproducing apparatus includes a mechanical deck having a disk receiver with a disk carrying unit for carrying a disk, a disk recording andor reproducing section for recording andor reproducing the disk received in the disk receiver, and an outer case housing the mechanical deck. The modules includes a rear face in which is mounted at least one fiber optic connector. Various systems and methods for synchronizing the execution of the iterations of the first graphical code portion with operation of measurement devices or other devices are also described. The third element includes: a first partial element which is elongated from the first element in a third direction; a second partial element which is elongated from the first partial element in a fourth direction; and a third partial element which is elongated from the second partial element. With the grooves 40, it is possible to partially reduce the rigidity of the vibration plate 30 at portions each of which surrounding one of the individual electrodes 32, thereby improving the driving efficiency of the piezoelectric actuator 3 and to reduce the crosstalk between adjacent pressure chambers 14.