A hard disk drive with a voice coil motor coupled to a head. The agitator repeats a given pattern of its forward and backward rotating actions thus to agitate and convey the treatment material throughout the casing. A data computation unit is configured for performing data conversion and is pipeline connected in sequence to the data load unit. In one form, the insert upper surface is flat to provide for line contact against the rod so as to minimize damage thereto. By applying current to the coil, the armature can be displaced from a rest position in the longitudinal direction. This invention further relates to methods for producing maize varieties derived from hybrid maize variety 34M78 and to the maize varieties derived by the use of those methods.