Seagate Technology Incorporated

Joshua Ward Christensen

Riyan Alex Mendonsa

Jon David Trantham

Edward Charles Gage

Tim Rausch

Timothy Francis Ellis

James Dillon Kiely

Mehmet Fatih Erden

Qiang Bi

Todd Michael Lammers

Jason Charles Jury

Puskal Prasad Pokharel

Peng Li

Song Wee Teo

Gary Ernest Hillukka

Jose Mari Toribio

Tze Pin Chin

Phan Linh Nguyen

David Allan Thorsvik

Renee Depew

Heather Lee Mallett

Wei Chen Lau

Chi Sern Georgie Tan

Mark A Gaertner

John Michael Bent

Brian Thomas Edgar

Kenneth A Haapala

Alfredo Sam Chu

Jason Wayne Riddering

John West Dykes

Drew Michael Mader

John Charles Purkett

Kent J Forbord

Richard P Michel

Daniel Dennis Dittmer

Brian Robert Pollock

Subra Nagarajan

Anil Kashyap

Justin Won

Ravi Hebbar

Wei Zhao

Richard Cox

Siong Liu

Chad Robert Barry

Nathan Andrew Blilie

Disclosed are hard disk drives (HDDs), and methods for use therewith, that utilize reduced overhead servo fields, thereby simplifying the servo system. Reduced overhead servo fields may be of particular use in HDDs that utilize multi-revolution storage techniques to store data at much higher densities than what is possible for conventional HDDs. The relaxed performance requirements of high-density, multi-revolution drives provides opportunities for reducing servo overhead, thereby potentially further increasing the areal density capability of the magnetic media. Servo overhead may also be reduced by placing certain servo data on flash or other memory off of the media disk rather than in the servo fields written to the media disk.

Multi-revolution hard disk drives with reduced servo overhead

Described are hard disk drives (HDDs) operable for archival applications and utilizing the same mechanical and electrical design of conventional HDDs. The capacity of a conventional HDD may be extended by up to 25% to 40% or more by employing multiple write and/or read spins before declaring success in write and read processes. The multiple write and/or read spins are designed to address the lower reliability that would otherwise result from high density packing of the data, at the cost of reducing performance. The result is an HDD with lower performance at higher capacity without sacrificing reliability and without altering conventional HDD mechanical or electrical design.

High-density archival storage using conventional hard disk drive architecture

The technology disclosed herein provides a method for generating an on-cylinder limit (OCLIM), the method including performing servo certification of a plurality of drives in a storage device to generate servo adaptive parameters (SAPs) by heads, generating a plurality of read adjust parameters (RAPs) by heads for the plurality of drives, generating an interim OCLIM value based on the SAPs by heads and RAPs by zones, and operating a disc drive write element using the interim OCLIM value.

Flexible on-cylinder limit for drive performance management

A method includes writing first data on a first track of a data storage surface, and storing information for the first data in a memory other than the data storage surface. The method also includes performing a write operation on a second track of the data storage surface after the data is written on the first track. The second track is adjacent to the first track. The method further includes identifying potentially-overwritten sectors of the first track as a result of the performance of the write operation on the second track, and performing a first read operation on the identified potentially-overwritten sectors of the first track after completion of the write operation on the second track. Second data associated with the identified potentially-overwritten sectors is then stored in a solid-state memory, and mirrored to media.

Managing data associated with overwritten portions of previously-written tracks

A hard disk drive includes a magnetic writer and a magnetic recording medium, which includes data tracks with user data sections positioned between servo wedges. The servo wedges each can include multiple servo sectors. The hard disk drive also includes circuitry programmed to cause the magnetic writer to write user data to the multiple servo sectors in multiple servo wedges.

Write once read many data storage devices

Systems and methods for servo zone transition optimization are described. In one embodiment, the storage system device includes a disk drive and a controller. In some embodiments, the controller may be configured to assess at least one operation of a read/write head of the disk drive; and format, based at least in part on the assessing of the read/write head, a disk surface of the disk drive with a first servo zone, a second servo zone, and an overlap region extending between a start point of the second servo zone and an end point of the first servo zone. In some cases, the overlap region starts towards a disk inner diameter (ID) and ends towards a disk outer diameter (OD).

Servo zone transition optimization for disk drives

An apparatus comprises a laser diode configured to generate light during a write operation. A slider comprises a near-field transducer (NFT) and an optical waveguide. The slider is configured for heat-assisted magnetic recording and to communicate the light to the NFT via the waveguide. A writer heater of the slider is configured to receive power during the write operation. A thermal sensor is situated at or near an air bearing surface of the slider. The thermal sensor is configured to produce a sensor signal in response to sensing back-heating from the medium while the NFT generates heat during a write operation. Circuitry, coupled to the thermal sensor, is configured to compare the sensor signal to a threshold and generate an output signal indicative of degradation of NFT performance in response to the sensor signal exceeding the threshold.

Performance monitoring of a near-field transducer of a heat-assisted magnetic recording slider

Servo zone transition optimization for magnetic disk recording devices

An apparatus comprises a laser diode configured to generate modulated light during a write operation in response to receiving modulated current having a mean amplitude that varies or is constant. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A writer heater of the slider is configured to receive power during the write operation having a magnitude that varies or is constant. A sensor is situated on or within the slider. The sensor is configured to produce a sensor signal representative of output optical power of the laser diode. Measuring circuitry is coupled to the sensor and configured to measure a change in the sensor signal indicative of a laser mode hop during the write operation.

Laser mode hop detection in a heat-assisted magnetic recording device using a slider sensor and laser modulation

Heat-assisted magnetic recording device capable of detecting degradation of NFT by measuring back-heat from medium

A heat-assisted magnetic recording head is moved relative to a magnetic recording medium. The medium comprises a plurality of sectors. The sectors define a plurality of sector groups distributed around a circumference of the medium. The sectors of each sector group are written using different operational currents supplied to a laser diode of the head such that at least one sector from each sector group is written using one of the different operational currents. For each of the different operational currents, an average write performance metric is calculated for all sectors written at each of the different operational currents. A particular operational current of the different operational currents is determined that results in a best average write performance metric.

Laser calibration for heat-assisted magnetic recording head using interleaved laser current

Before writing to a heat-assisted magnetic recording medium, a DC signal modulated with an AC signal is applied to a laser of a read/write head. A modulation level of an optical power sensor is measured, the optical power sensor being coupled to detect optical output of the laser in response to the modulated current. A target value of the DC signal that causes the modulation levels to reach a predetermined value between zero and a maximum value is determined and used to set a bias current for subsequent activation of the laser based.

Setting laser current based on modulation level of an optical power sensor measurement

Method and apparatus for recovering user data from a rotatable data recording medium. In some embodiments, a moveable read element detects at least one uncorrectable read error in user data stored in a data sector arranged along a concentric track. A read retry operation is carried out to recover the user data by radially advancing the moveable read element from a first offset value to a different second offset value with respect to the track in accordance with a trajectory profile while transducing the user data from the data sector. This allows data that are variably overwritten (encroached upon) by different radial amounts from an adjacent track to be recovered.

Recovering user data from a variably encroached data track

A storage media includes a plurality of servo sectors with embedded servo patterns characterized by one or more servo pattern parameters. Each of the servo sectors has a servo pattern parameter based on a separation between read sensors of a transducer head reading the servo sector.

Servo parameterization for multi-sensor reader

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Savage, MN, United States of America

Joshua Ward Christensen