Western Digital Technologies, Inc.

Maxtor Corporation

Wing Ying

Siri S Weerasooriya

Tehri S Lee

Yakov M Lifchits

Robert L Cloke

Jack M Chue

Brian P Rigney

Edgar D Sheh

Lawrence Matthias Bryant

Yilin Cai

William W Clawson

Monica Kuan

Tainshain Lee

Hsiang Chen Wu

A disk drive is disclosed comprising a first disk surface and a second disk surface, wherein the first disk surface comprises a plurality of concentric servo sectors extending across substantially an entire radius of the first disk surface. The concentric servo sectors are read across substantially the entire radius of the first disk surface using the first head to generate a read signal. The read signal is processed to generate a position error signal (PES) representing a radial location of the first head relative to the first disk surface. The PES is processed to generate a control signal applied to the VCM to move the second head radially over the second disk surface while writing a spiral servo track on the second disk surface.

Servoing on concentric servo sectors of a first disk surface to write a spiral servo track to a second disk surface

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 and apparatus is disclosed for adjusting the track density by changing the slope of spiral tracks used to servo write a disk drive. A target track density is established for a disk surface, and a plurality of spiral tracks are written to the disk surface in response to the target track density. Each spiral track comprises a high frequency signal interrupted at a predetermined interval by a sync mark, and a slope of the spiral tracks is selected in response to the target track density. The head internal to the disk drive is used to read the spiral tracks in order to write product servo sectors to the disk to define a plurality of data tracks, wherein the slope of the spiral tracks determines the density of the data tracks.

Adjusting track density by changing slope of spiral tracks used to servo write a disk drive

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 method and apparatus is disclosed for writing product servo sectors to a disk of a disk drive to define a plurality of data tracks. The disk drive comprises the disk and a head actuated over the disk. The disk comprises a plurality of spiral tracks which are read using the head to synchronize a write clock and to generate a position error signal (PES) according to a PES algorithm used to maintain the head along a first servo track while writing product servo sectors along the first servo track. The PES algorithm is adjusted to seek the head to a second servo track, and the head is used to write product servo sectors along the second servo track.

Adjusting track density by changing PES algorithm when servo writing a disk drive from spiral tracks

A method is disclosed for reducing disk expansion effects while writing spiral reference patterns on a disk of a disk drive. The disk drive comprises control circuitry and a head disk assembly (HDA) for positioning a head radially over the disk. In the method, an external spiral servo writer is used to control a radial location of the head for writing a plurality of the spiral reference patterns between inner and outer seed tracks. A head velocity profile is adjusted for writing each spiral reference pattern to account for thermal disk expansion. The head internal to the disk drive is used to read the spiral reference patterns in order to write product servo bursts to the disk that define a plurality of radially-spaced circular data tracks.

Method for reducing disk thermal expansion effects while writing reference spiral servo patterns to a disk of a disk drive

An apparatus for sustaining data throughput and methods of operating the same result in a drive apparatus that reduces overhead associated with recovery from write faults. The drive apparatus for sustaining data throughput having a file allocation unit including a plurality of sectors for storing data comprises a write controller coupled to the file allocation unit configured to write data to the plurality of sectors, a write fault detector coupled to the write controller and the file allocation unit configured to detect a write fault, and a write fault controller coupled to the write controller, the write fault detector, and the file allocation unit responsive to a detected write fault to skip a defective sector and restart the write controller to continue writing data to the plurality of sectors.

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Fremont, CA, United States of America

Wing Ying