Seagate Technology Incorporated

Jason Charles Jury

Ara Patapoutian

Raman Venkataramani

Jason Bellorado

Tim Rausch

Deepak Sridhara

Michael John Link

Xiong Liu

Mark A Gaertner

Marcus Marrow

Jon David Trantham

Wenzhong Zhu

Mehmet Fatih Erden

Housan Dakroub

Quan Li

Joshua Ward Christensen

Pierre Asselin

Rishi Ahuja

Xiaowei Wu

Kaizhong Gao

Edward Charles Gage

Song Sheng Xue

Shaoping Li

Myint Ngwe

Brian Thomas Edgar

Todd Michael Lammers

Alfredo Sam Chu

William Michael Radich

Drew Michael Mader

Steven Douglas Granz

Zheng Wang

Prafulla Bollampalli Reddy

Pu-Ling Lu

Anil Kashyap

Richard Jay Parshall

Mike Montemorra

Siong Liu

Jin Insik

A method of recovering data from one or more failed data sectors includes estimating a reader offset position from a first or a second read attempt of the one or more failed data sectors at a current set of channel parameters and basing the estimated reader offset position on, at least in part, a position error signal generated during the first or second read attempt. At least one read is performed on the one or more failed data sectors at the estimated reader offset position to obtain one or more samples. The one or more samples are processed to obtain a processed sample. Iterative outer code recovery is performed on the processed sample.

Composite data recovery procedure

A method includes encoding a sector of data to be written to a data storage device with a single error correcting code (ECC). The sector of data is divided into N individually readable and writeable portions, with N&#x2265;2. The individually readable and writeable portions of the sector of data are separated with a space between the portions of the sector of data in a pattern.

Coarse interleaving

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

An apparatus may include a circuit that initializes a read operation to read one or more requested data segments of a respective data unit. The circuit may generate equalized combined samples for a failed data segment of the one or more requested data segments based on first samples and second samples. In addition, the circuit may perform iterative outer code recovery for the data unit utilizing the equalized combined samples as samples for the failed data segment.

Iterative outer code recovery using data from multiple reads

An apparatus may include a circuit configured to generate a set of first ADC samples based on a first signal associated with a first read head position and a failed segment and to generate a set of second ADC samples based on a second signal associated with a second read head position and the failed segment. The circuit may then generate, by a MISO equalizer, a set of equalized ADC samples based on the set of first ADC samples and the set of second ADC samples.

MISO equalization with ADC averaging

First tracks of a disk are read via a first read transducer. The first read transducer has a first crosstrack width and a first shield-to-shield spacing that are optimized to read a first track width and a first linear bit density of the first tracks. Second tracks interlaced between the first tracks are read via a second read transducer. The second read transducer has a second crosstrack width different from the first crosstrack width and second shield-to-shield spacing different than the first shield-to-shield spacing. The second crosstrack width and the second shield-to-shield spacing are optimized to read a second track width different from the first track width and a second linear bit density different from the first linear bit density.

Head with multiple readers configured for reading interlaced magnetic recording tracks

An error is determined in a target track of a heat-assisted recording medium. The error triggers an error recovery procedure. The error recovery procedure involves storing data from at least part of an adjacent track that is immediately proximate the target track to another data storage location. The error recovery procedure also involves, for two or more iterations in which a laser power is incrementally changed from a lower power to a higher power, erasing at least part of the adjacent track at the laser power and attempting to recover the target track.

Heat-assisted magnetic recording error-recovery by erasing adjacent tracks using laser

A recording medium is written to using an energy source that heats the medium during the writing. A read error in a sector is determined when reading via a read transducer. While traversing a part of the recording medium that includes data, a write coil is activated before attempting to re-read the sector. The energy source does not heat the recording medium sufficiently to change a state of the data during the activation of the write coil. The activation of the write coil removes a magnetic instability of the read transducer.

Activating a magnetic writer to recover from read errors due to reader instability

A circuit may be configured to adaptively combine two or more waveforms into a single waveform. The circuit can generate weighting factors based on received error signals, and can apply the weighting factors to the two or waveforms to be combined. In some examples, a circuit can be configured to receive input signals, receive error signals, generating a weighting coefficient based on at least some of the error signals, and determine an output signal based on the weighting coefficient and the input signals.

Adaptively combining waveforms

In a method, read signals from each of a plurality of read transducers of a data head are buffered for each of a plurality of cross-track positions of the head relative to a data track. The buffered read signals are processed to establish a quality metric for each of the read signals and at least one combination read signal comprising at least two of the read signals. A data recovery cross-track position and a reader configuration comprising one or more of the read transducers are identified based on the quality metrics. A data read operation is then performed with the data head in the data recovery cross-track position using the read signals from the identified reader configuration.

Data recovery using a multi-reader head

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

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.

Obtaining a predetermined phase shift in data using different write precompensation associated with different NRZI patterns

Method and apparatus for storing and retrieving user data from magnetic recording tracks in a data storage device. In some embodiments, a rotatable data recording medium has a circumferentially extending data track formed from spaced apart embedded servo wedges that extend radially across a recording surface of the medium to define intervening data wedges between each adjacent pair of the servo wedges. Each data wedge along the data track has only a single timing field at a beginning portion of the data wedge immediately adjacent a first servo wedge, followed by a plurality of data sectors that extend across the data wedge to an end portion of the data wedge immediately adjacent a second servo wedge. No inter-sector gaps are provided between the respective data sectors and no additional timing fields are provided between the first and second servo wedges.

Magnetic recording tracks with consolidated timing fields and no inter-sector gaps

An apparatus comprises a heat-assisted magnetic recording head configured to write to and read from a magnetic recording medium. The head comprises a reader and a writer including a near-field transducer (NFT). The reader comprises a center which is laterally offset relative to a center of the writer to define a reader-writer offset (RWO) therebetween. A magnetic recording medium comprises a plurality of tracks. The plurality of tracks comprises at least one track used as a region to test for a shift in the RWO. A processor is coupled to the recording head and configured to detect the RWO shift.

Growing community of inventors

Minneapolis, MN, United States of America

Jason Charles Jury