公开(公告)号：US10665254B1

公开(公告)日：2020-05-26

申请号：US16412928

申请日：2019-05-15

Applicant: Seagate Technology LLC

Inventor： Drew Michael Mader ,  Wenzhong Zhu

IPC: G11B5/09 ,  G11B5/00

Abstract: A read channel is configured to obtain an analog readback waveform from a magnetic recording medium of a disk drive at a sampling rate of one sample per one written bit. A buffer is coupled the read channel. Circuitry is configured to inject a plurality of different phase offsets into the read channel for each of a plurality of revolutions of the medium. The circuitry is also configured to store, in a buffer, an amplitude of the readback waveform for each of the different phase offsets. The circuitry is further configured to generate an oversampled readback waveform using the amplitudes stored in the buffer.

公开(公告)号：US20190287554A1

公开(公告)日：2019-09-19

申请号：US16170445

申请日：2018-10-25

Applicant: Seagate Technology LLC

Inventor： Alfredo Sam Chu ,  Franklin P. Martens ,  Drew Michael Mader ,  Steven J. Kimble ,  James E. Angelo

IPC: G11B5/02 ,  G11B5/60

Abstract: A temperature compensation equation is generated during manufacture of a heat-assisted magnetic recording (HAMR) disk drive using initial total currents supplied to a laser diode of the disk drive at different initial operating temperatures. The total currents represent currents for recording data to or erasing data from the medium. The temperature compensation equation is stored in the disk drive, and updated, during field operation, using a subsequent total current associated with an operating temperature differing from the initial operating temperatures. The total current supplied to the laser diode for a subsequent write operation is adjusted using the updated temperature compensation equation in response to the operating temperature at the time of the subsequent write operation.

公开(公告)号：US10127930B1

公开(公告)日：2018-11-13

申请号：US15919386

申请日：2018-03-13

Applicant: Seagate Technology LLC

Inventor： Alfredo Sam Chu ,  Franklin P. Martens ,  Drew Michael Mader ,  Steven J. Kimble ,  James E. Angelo

IPC: G11B5/02 ,  G11B5/60 ,  G11B5/00

Abstract: A temperature compensation equation is generated during manufacture of a heat-assisted magnetic recording (HAMR) disk drive using initial total currents supplied to a laser diode of the disk drive at different initial operating temperatures. The total currents represent currents for recording data to or erasing data from the medium. The temperature compensation equation is stored in the disk drive, and updated, during field operation, using a subsequent total current associated with an operating temperature differing from the initial operating temperatures. The total current supplied to the laser diode for a subsequent write operation is adjusted using the updated temperature compensation equation in response to the operating temperature at the time of the subsequent write operation.

公开(公告)号：US10083716B1

公开(公告)日：2018-09-25

申请号：US15678440

申请日：2017-08-16

Applicant: Seagate Technology LLC

Inventor： Alfredo Sam Chu ,  Drew Michael Mader ,  Joshua Ward Christensen ,  Jason W. Riddering

IPC: G11B11/00 ,  G11B7/1267 ,  G11B20/12 ,  G11B5/455 ,  G11B5/00 ,  G11B7/126 ,  G11B7/1263 ,  G11B5/60

CPC classification number: G11B7/1267 ,  G11B5/455 ,  G11B5/5534 ,  G11B5/6088 ,  G11B7/126 ,  G11B7/1263 ,  G11B20/10027 ,  G11B20/1217 ,  G11B2005/0021 ,  G11B2020/1232

Abstract: 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.

公开(公告)号：US09830942B1

公开(公告)日：2017-11-28

申请号：US15233298

申请日：2016-08-10

Applicant: Seagate Technology LLC

Inventor： Drew Michael Mader ,  Jason Charles Jury ,  Tim Rausch ,  Raman Venkataramani

IPC: G11B11/00 ,  G11B20/10 ,  G11B5/00 ,  G11B20/14

CPC classification number: G11B20/10481 ,  G11B20/10009 ,  G11B20/10194 ,  G11B20/1407 ,  G11B20/1426 ,  G11B2005/0021

Abstract: First and second different write precompensation values are associated with different first and second non-return-to-zero, inverted (NRZI) data patterns. The first and second different write precompensation values cause a predetermined phase shift to be written into test data that comprises the first and second NRZI data patterns. The test data is mitten to a recording medium of a storage device using the first and second write precompensation value. The test data is used to determine a response of the storage device to the predetermined phase shift.

公开(公告)号：US09311951B1

公开(公告)日：2016-04-12

申请号：US14864202

申请日：2015-09-24

Applicant: Seagate Technology LLC

Inventor： Alfredo Sam Chu ,  Drew Michael Mader ,  Wenzhong Zhu ,  Michael A. Cordle

IPC: G11B7/1263 ,  G11B20/18 ,  G11B5/02 ,  G11B7/1267 ,  G11B5/00 ,  G11B5/455 ,  G11B5/012

CPC classification number: G11B7/1267 ,  G11B5/012 ,  G11B5/02 ,  G11B5/455 ,  G11B5/5534 ,  G11B13/08 ,  G11B20/10009 ,  G11B20/10481 ,  G11B20/10509 ,  G11B20/182 ,  G11B2005/0021

Abstract: During field operation of a heat-assisted magnetic recording data storage device, a laser adjustment procedure is repeatedly performed. The laser adjustment procedure involves writing, at a designated location on a recording medium at least three tracks at an unsqueezed pitch, a first track being in the middle of the at least three tracks. A first bit error rate of the first track is compared with a reference bit error rate. In response to the comparison satisfying a threshold, the laser current is swept while recording squeezed test tracks at the designated location to determine a new laser current that results in a minimum bit error rate. The new laser current is used for subsequent write operations.

Abstract translation: 在热辅助磁记录数据存储装置的现场操作期间，重复执行激光调节程序。 激光调整程序涉及在非压缩间距的至少三个轨道上在记录介质上的指定位置处写入至少三个轨道中间的第一轨道。 将第一轨道的第一误码率与参考误码率进行比较。 响应于满足阈值的比较，激光电流被扫描，同时在指定位置记录挤压的测试轨迹，以确定导致最小误码率的新的激光电流。 新的激光电流用于后续写入操作。

公开(公告)号：US10395673B1

公开(公告)日：2019-08-27

申请号：US16170445

申请日：2018-10-25

Applicant: Seagate Technology LLC

Inventor： Alfredo Sam Chu ,  Franklin P. Martens ,  Drew Michael Mader ,  Steven J. Kimble ,  James E. Angelo

IPC: G11B5/02 ,  G11B5/60 ,  G11B5/00

Abstract: A temperature compensation equation is generated during manufacture of a heat-assisted magnetic recording (HAMR) disk drive using initial total currents supplied to a laser diode of the disk drive at different initial operating temperatures. The total currents represent currents for recording data to or erasing data from the medium. The temperature compensation equation is stored in the disk drive, and updated, during field operation, using a subsequent total current associated with an operating temperature differing from the initial operating temperatures. The total current supplied to the laser diode for a subsequent write operation is adjusted using the updated temperature compensation equation in response to the operating temperature at the time of the subsequent write operation.

公开(公告)号：US09990950B1

公开(公告)日：2018-06-05

申请号：US15651299

申请日：2017-07-17

Applicant: Seagate Technology LLC

Inventor： Drew Michael Mader ,  Steven J. Kimble ,  Jason W. Riddering

IPC: G11B11/00 ,  G11B5/60 ,  G11B20/10 ,  G11B5/00 ,  G11B7/126 ,  G11B7/1263 ,  G11B7/1267

CPC classification number: G11B5/6029 ,  G11B5/5534 ,  G11B5/607 ,  G11B5/6076 ,  G11B5/6088 ,  G11B7/126 ,  G11B7/1263 ,  G11B7/1267 ,  G11B20/10388 ,  G11B2005/0021

Abstract: An apparatus comprises a slider configured for heat-assisted magnetic coupled to a controller. The slider comprises a writer, a heater, a near-field transducer, and an optical waveguide for communicating light from a laser diode to the near-field transducer. The controller is configured to set a target pre-write clearance of the slider prior to performing a write operation, set a target write clearance of the slider for performing the write operation, and determine a difference between the target pre-write and write clearances to define a target pre-write clearance offset. The controller is also configured to measure, for a plurality of different target pre-write clearance offsets, a writability metric for the slider while sweeping a laser diode current, and adjust the target pre-write clearance offset so that the writability metric reaches a predetermined threshold. The controller is further configured to perform subsequent write operations using the adjusted target pre-write clearance offset.

公开(公告)号：US09842621B1

公开(公告)日：2017-12-12

申请号：US15246835

申请日：2016-08-25

Applicant: Seagate Technology LLC

Inventor： Drew Michael Mader ,  Tim Rausch ,  James E. Angelo

IPC: G11B11/00 ,  G11B20/10 ,  G11B20/18 ,  G11B5/012 ,  G11B7/126 ,  G11B5/00 ,  G11B7/1267 ,  G11B7/1263 ,  G11B5/60 ,  G11B11/105

CPC classification number: G11B20/105 ,  G11B5/012 ,  G11B5/6088 ,  G11B7/126 ,  G11B7/1263 ,  G11B7/1267 ,  G11B11/10506 ,  G11B11/1051 ,  G11B20/10009 ,  G11B20/1816 ,  G11B2005/0021

Abstract: An apparatus determines that phase errors have exceeded a threshold when reading data previously recorded to a heat-assisted recording medium. In response to the phase errors exceeding the threshold, remedial action is taken to prevent loss of data due changes in power applied to heat the heat-assisted recording medium when recording.

公开(公告)号：US09837118B1

公开(公告)日：2017-12-05

申请号：US15447337

申请日：2017-03-02

Applicant: Seagate Technology LLC

Inventor： Drew Michael Mader ,  Tim Rausch

IPC: G11B11/00 ,  G11B20/18 ,  G11B5/012 ,  G11B5/09 ,  G11B5/00

CPC classification number: G11B5/09 ,  G11B5/012 ,  G11B20/10398 ,  G11B2005/0021

Abstract: Data is written to a magnetic recording medium of a drive using a read/write head. The read/write head has an energy source that applies a hotspot to the magnetic recording medium while recording. During the writing, a steady-state current applied to the energy source is changed by a step value. A timing error induced by the change in the steady-state current is measured based on reading back the data. A thermal gradient of the hotspot is determined based on the step value and the timing error.