Head positioning control manner null of head disk assembly and its production manner and disk unit of

摘要

PURPOSE:To quicken the head positioning by providing each head parted relatively by a predetermined distance in the radial direction of a data face with respect to a same cylinder on each data face as a reference. CONSTITUTION:When a 1st face head 1a comes just above a 1st face n-th track 3b and there is no position deviation, that is, an offtrack is zero, an offtrack of a 2nd face head 1b, a 3rd face head 1c, a 4th head 1d is respectively offset so that they have offtrack of a multiple of 1/4, a multiple of 2/4, a multiple of 3/4 in relation to a track pitch in the direction of the (n-1)th track with respect to a 2nd face n-th track 3b, a 3rd face n-th track 3c, and a 4th face n-th track 3d among the heads 1a - 1c respectively. When a seek instruction to an adjacent cylinder resulting in switching the head comes from a host device, the head positioning is implemented to an adjacent track by having only to apply the control in the following control mode. Thus, the head positioning is quickened.