Hitachi Global Storage Technologies Netherlands B.v.

Manabu Saikawa

Hirofumi Yanase

Atsushi Takeichi

Kenji Kuroki

Mitsuhiro Shoda

Kazuhiko Washizu

Yuki Hashimoto

A disk drive. The disk drive includes a plurality of head-sliders, an actuator, a plurality of clearance adjustment sections, and a controller. Each head-slider includes a slider and a magnetic-recording head on the slider for accessing a disk for storing data. The plurality of head-sliders is secured to the actuator that is configured to move the plurality of head-sliders concurrently. Each clearance adjustment section corresponds to each head-slider of the plurality of head-sliders and adjusts a clearance of the corresponding head-slider. In addition, the controller is configured to position the actuator by servo control with a first head-slider selected from the plurality of head-sliders, to change a clearance of a second head-slider different from the first head-slider by controlling a clearance adjustment section of the second head-slider to bring the second head-slider into contact with a disk, and to detect the contact to measure the clearance of the second head-slider.

Disk drive, method for measuring clearance and method for writing servo patterns

Embodiments in accordance with the present invention ensure that the pitch of a servo write track is accurately controlled. According to one embodiment of the present invention, a Self Servo Write (SSW) uses different methods and sequences to identify read-write offsets (RWOs) and calculate target positions in inner and outer diameter sides of a magnetic disk. In the inner diameter-side area, the SSW controller uses the readout of a radial pattern written on a recording surface and a reference value to identify the RWO. The SSW controller uses the RWO value identified in the inner diameter-side area to anticipate an RWO value in the outer diameter-side area. In the outer diameter-side area, the SSW controller uses the anticipated RWO value to determine the target position of each servo write track.

Method and apparatus for writing pattern on disk

Provided is a data storage device in which read and write heads can be desirably located with respect to servo tracks from the viewpoint of linearity of a PES on the premise that a read write offset exists. A read write offset value, which is a deviation amount between write and read heads in a radial direction of a disk-shaped storage medium, is set equivalent to an integer number N of servo tracks.

Data storage device and servo information writing method

Provided is a data storage device in which servo track pitch varies within a predetermined region in a radial direction of a disk-shaped storage medium.

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Kanagawa, Japan

Manabu Saikawa