Western Digital Technologies, Inc.

Jinsheng Bill Jang

Jie Yu

Teddy T C Chen

Jonathan V Nguyen

Masao Miyamura

Shih Min Liu

A disk drive operable with first and second servo patterns in a perpendicular media recording (PMR) environment is disclosed. The disk drive comprises a head operable with a perpendicular flux, a disk, and a servo controller. The disk includes a plurality of tracks, wherein each track has a plurality of servo sectors utilized in seek operations. The servo sectors of the disk include a first servo pattern between one of an inner diameter (ID) or an outer diameter (OD) of the disk and a middle diameter (MD) of the disk, respectively, and a second servo pattern between the other of the OD or the ID of the disk and the MD of the disk, respectively. The servo controller operates in a first mode when seeking within one of the first or second servo patterns and a second mode when seeking between the first servo pattern and the second servo pattern.

Disk drive operable with first and second servo patterns in a perpendicular media recording environment

A method of servo writing a disk of a disk drive is disclosed, wherein the disk drive comprising the disk and a head actuated over the disk. Servo sectors are written to define servo tracks from a first diameter of the disk to substantially a middle diameter of the disk, wherein the first diameter is selected from one of the outer and inner diameter of the disk. Servo sectors are then written to define servo tracks from a second diameter of the disk toward the middle diameter of the disk by positioning the head over a current servo track, reading the current servo track to generate a read signal, processing the read signal to detect a previously written servo sector, and if a previously written servo sector is not detected, then writing servo sectors to the current servo track and positioning the head over a next servo track.

Servo writing a disk drive with a controlled overlap near the middle diameter of the disk

A perpendicular media recording (PMR) servo track writer (STW) system and method for writing servo sectors onto a disk is disclosed. The servo writer includes a head positioner to position a head of a head disk assembly (HDA) relative to a disk, wherein the head writes servo sectors onto the disk with a perpendicular flux. The servo writer includes a controller to control the head positioner such that the head writes servo sectors onto the disk from one of an inner diameter (ID) or an outer diameter (OD) of the disk to a middle diameter (MD) of the disk, respectively, followed by writing servo sectors between the other of the OD or the ID of the disk to the MD of the disk, respectively.

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Irvine, CA, United States of America

Jinsheng Bill Jang