A connector that can couple a flexible circuit board of a head gimbal assembly to driving circuits of an apparatus coupled to a hard disk. When the robot walks, a knee is maximally stretched and a horizontal movement of a waist is minimized such that the walking pattern of the robot is maximally similar to that of a human, thus enhancing an affinity for a human being and increasing energy efficiency. The intended receiving party responds with a request-for-mail-content to request for the electronic mail message if the intended receiving party determines to do so.