Western Digital Technologies, Inc.

Maxtor Corporation

Yakov M Lifchits

Siri S Weerasooriya

Lawrence Matthias Bryant

Wing Ying

Michael Anthony Moser

Brian P Rigney

Charles A Park

Edgar D Sheh

Stanley H Shepherd

Yilin Cai

Boworn Panyavoravaj

Steven C Smith

Ching-Tzuen Tarn

Mohamad A Rezvani

In an embodiment of the present invention, a disk drive comprises a head actuated over a disk including a plurality of spiral tracks, wherein each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark. The read signal from the head is processed to detect a plurality of the sync marks in spiral track crossings. A plurality of timing recovery measurements are generated corresponding to the detected sync marks, and the timing recovery measurements are biased based on a radial location of the head. A servo write clock is generated in response to the biased timing recovery measurements, and the servo write clock is used to write product servo sectors to the disk.

Disk drive biasing timing recovery measurements for spiral tracks based on radial location of head

A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of spiral tracks. A first sync frame is first opened in response to a first frame offset during a first revolution of the disk, wherein the first sync frame corresponds to the head approaching a first sync mark in a first spiral track crossing. A first sync frame position error signal (PES) is generated representing a difference between a target framing of the first sync frame around the first sync mark and a detected framing of the first sync frame around the first sync mark. The first frame offset is adjusted in response to the first sync frame PES, and during a second revolution of the disk the first sync frame is second opened in response to the adjusted first frame offset.

Disk drive centering sync frames on sync marks of a spiral track

A disk drive is disclosed comprising a disk, and a head actuated over the disk. The head is positioned at a radial location over the disk, and a servo burst is written at the current radial location. The servo burst is read to generate a read signal, and the read signal is processed to generate a position error signal (PES). The head is moved radially in response to the PES, and the process is repeated multiple times to form a spiral track spanning at least one revolution of the disk.

Disk drive self servo writing spiral tracks by propagating bursts

A disk drive is disclosed comprising control circuitry for self servo writing a disk. An estimated reader/writer offset is initialized, servo bursts in a first servo track are read, the head is moved radially using the estimated reader/writer offset, and propagated servo bursts are written to a target servo track. The propagated servo bursts are read from the target servo track to generate a read signal, the read signal is processed to generate a burst crossing signal (BCS), and the estimated reader/writer offset is adjusted in response to the BCS.

Disk drive adjusting estimated reader/writer offset to achieve target burst crossing signal amplitude when propagating servo sectors

A method of writing product servo sectors on a disk of a disk drive is disclosed. The disk comprises a reference pattern having a plurality of sync marks written around the disk. The sync marks are detected to generate a sync mark detect signal, and a timing recovery measurement is generated in response to the sync mark detect signal. A frequency control signal is generated in response to the timing recovery measurement, and a servo write clock is generated in response to the frequency control signal. A feed-forward compensation value is generated in response to the timing recovery measurement and the frequency control signal, and the timing recovery measurement is adjusted in response to the feed-forward compensation value to compensate for a repeatable phase error in the timing recovery measurement. The servo write clock and the head internal to the disk drive are used to write the product servo sectors to the disk.

Servo writing a disk drive by synchronizing a servo write clock to a reference pattern on the disk and compensating for repeatable phase error

A spindle motor control for a disk drive including a spindle motor for rotating a data disk at a desired rotational speed, and a data transducer head positionable relative to selected ones of a multiplicity of concentric data tracks formed on a data storage surface of the data disk by a head position actuator structure operating within a head position servo loop, wherein the concentric data tracks are periodically interrupted by a plurality of servo sectors per rotation, each servo sector recorded with head position information. The spindle motor control includes: a servo detector for detecting the head position information in at least one servo sector on a selected track under the transducer head in relation to a timing signal at a reference frequency; a position detector for determining the circumferential position of the detected head position information on the selected track in relation to the timing signal; and a controller for controlling the rotational speed of the spindle motor as a function of said circumferential position, to regulate the circumferential position of the transducer in relation to the servo sectors on the data tracks.

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San Jose, CA, United States of America

Yakov M Lifchits