Track mis-registration correction is conditionally made in a hard disk drive using servo data in a closed loop servo control scheme, along with one or more alternative sensing schemes when an external shock or vibration occurs. Each belt link is substantially identical, and has a front edge, a rear edge, two side edges, an upper surface, and an under surface between the edges. Thus, noise is removed without modifying the design of the filter circuit depending on the system in which the memory module is incorporated. The pivoting member has a first side part configured to receive driving force from the motor in first and second rotational directions, and a second side part relatively unrotatably coupled to the first side part. At the end of a video conversation, in accordance with the user’s selection, a picture indicating that the virtual character disappears from the screen is displayed before disconnecting the line. The distributed sensor array may comprise optical transmitters and optical receivers configured such that they may be individually addressed and activated.