Seagate Technology Incorporated

Barmeshwar Vikramaditya

Bruce Douglas Buch

Puskal Prasad Pokharel

Mustafa Can Ozturk

Patrick J Korkowski

Mehmet Fatih Erden

Jimmie Ray Shaver

Sundeep Chauhan

Jon David Trantham

William Michael Radich

Ralph William Cross

Scott Robert Warmka

Edward Charles Gage

James Gary Wessel

Tim Rausch

Jason Bryce Gadbois

Housan Dakroub

Timothy Francis Ellis

Deepak Sridhara

James Dillon Kiely

John West Dykes

Raul Horacio Andruet

Jon Karsten Klarqvist

Rene Johannes Marinus Van De Veerdonk

Thomas C Zirps

Michael Ray Tiller

Richard Lyle Keizer

Huaan Zhang

Yongjun Hou

Charles Paul Henry

Fatih Erden

Puskal Prassad Pokharel

An apparatus and associated methodology providing read channel circuitry having a signal equalizer that sends an equalized signal to a bit detector. The read channel circuitry is capable of sampling values of the equalized signal to identify a bit transition from among a predefined plurality of different bit transitions. The apparatus may have channel optimization (CO) logic that, based on the input signal and the sampling of the equalized signal, defines first values for a programmable parameter of the bit detector that substantially maximizes vector separations among vectors of waveform target samples corresponding to the predefined plurality of different bit transitions, while the CO logic also defines second values for a programmable parameter of the equalizer that substantially minimizes the mean squared separation of the equalized signal segment for each bit transition from the waveform target corresponding to that bit transition.

Jointly optimizing signal equalization and bit detection in a read channel

The disclosure is related to apparatuses and methods for characterizing and compensating for curvature in a write field generated by a data storage device transducer. In some embodiments, the curvature of a write field generated by a data storage device transducer may be characterized. Some embodiments can include a circuit to apply a phase compensation value based on a deterministic phase offset value, which may correspond with the write field curvature characterization.

Transducer write field curvature characterization and compensation

Method and apparatus for detecting unstable read sensors (readers) for data storage systems. In some embodiments, a transducer is supported adjacent a rotating data recording medium having servo data patterns interspersed with calibration test data patterns. A read sensor of the transducer reads the servo and calibration test data patterns while the transducer is maintained at a passive fly height adjacent the medium. A corresponding location on the medium is identified for an error detected during the reading of the servo and calibration test patterns. The servo and calibration test patterns at the location are reread using the read sensor to characterize the read sensor as an unstable reader.

Unstable reader detection

A circuit may be configured to reduce the amount of space used on a storage device when a transducer having a reader and writer passes from a writable data field to a read-only field by enabling both the reader and writer simultaneously. The circuit can be configured to reduce to a threshold level the noise on a read signal that can occur when the reader is over a read-only field and the writer is over a writable data field, and can ignore the read data when both the writer and reader are enabled simultaneously over a writable data field.

Read read-only fields while writing

Apparatus and method for detecting media defects using a multi-sensor transducer. In some embodiments, a first pattern is written to a first track on a rotatable storage media and a second pattern is written to a second track on the media. A first read sensor of a multi-sensor transducer senses the first pattern from the first track and a second read sensor of the multi-sensor transducer concurrently senses the second pattern from the second track. At least one storage media defect is detected responsive to the sensed first and second patterns.

Multi-sensor media defect scan

A system comprises a disk writer servo head and a controller. The disk writer servo head is configured to be positioned by a micro actuator. The disk writer servo head is also configured to substantially, continuously alternate between reading a first servo pattern and writing a second servo pattern until a disk is substantially, completely servo written. The first servo pattern establishes a first position of the disk writer servo head and the second servo pattern establishes a second position of the disk writer servo head. The controller is configured to control the operation of the disk writer servo head. The controller is also configured to compare the first and second positions to establish a position error. The micro actuator is configured to reposition the disk writer servo head in response to the position error prior to a next reading.

Multi-disk writer with individual head positioning

The disclosure is related to systems and methods for achieving improved servo Gray code error detection and correction. A device may include a circuit configured to read servo data that is encoded using a Gray code encoding scheme to produce servo Gray code, read one or more Check bits associated with the servo Gray code, determine whether a read or write head is positioned over a target data track based on the servo Gray code and the one or more Check bits, and execute a read or write operation when the read or write head is positioned over the target data track.

Servo gray code check bits

A readback signal from a first reader and a readback signal from a second reader are received, the first reader and the second reader configured to read two-dimensional data from at least one track of a recording media. A quality metric of the second reader is measured based on the readback signal. It is determined if the quality metric for the second reader is above a threshold. If the quality metric is above the threshold, the first reader and the second reader are used to read the data.

Requirement relaxation for multiple readers in presence of large skew angle range

An apparatus includes a write element configured to apply a magnetic field to write data on a portion of a heat-assisted magnetic recording media in response to an energizing current. An energy source is configured to heat the portion of the media being magnetized by the write element. A preheat energizing current is applied to the write element during an interval before writing the data to the portion of the media. The preheat energizing current does not cause data to be written to the media and brings at least one of the write element and driver circuitry into thermal equilibrium prior to writing the data on the portion.

Heat assisted magnetic recording device with pre-heated write element

Apparatuses, devices, and systems are presented with servo and data pattern formation using multi-dot arrays. In one example, an apparatus may comprise a data storage medium including a first patterned array of dots of magnetic material, a second patterned array of dots of magnetic material, and a non-magnetic space located between the first patterned array and second patterned array. In another example, a system may comprise a processor configured to store data to a data storage medium, the data storage medium including a first dot composite including a first patterned array of dots of magnetic material, a second dot composite including a second patterned array of dots of magnetic material, and a non-magnetic space located between the first dot composite and second dot composite. An order in which a dot composite and a non-magnetic space occur may define the value of one bit.

Data storage mediums and devices having bit patterned media

The defined architecture allows for format-efficient data storage on bit-patterned media, while allowing for typical variations in the drive, such as reader to writer gap variations. The defined BPM architecture relaxes some timing requirements on real-time signaling from the formatter to the channel, while enabling bit-accurate alignment between data accesses and the media.

Data access formatter

The disclosure is related to systems and methods for servo Gray code error detection and correction. A device may include a circuit configured to 1) selectively implement a quality-based error correction system to determine an error in the servo Gray code and correct the error; 2) selectively implement a trajectory-based error correction system to determine an error in the servo Gray code and correct the error; or 3) implement any combination of a quality-based error correction system and a trajectory-based error correction system to determine an error in the servo Gray code and correct the error.

Servo grey code error correction

Technologies are described herein for implementing modulation coding schemes for TDMR. A data sequence is received to be stored on a first data track of a recording media. The first data sequence is encoded into a first codeword sequence using a modulation coding scheme, and the first codeword sequence is written to the first data track of the recording media. Subsequently, a second data sequence is received to be stored on a second data track of the recording media, the second data track being adjacent to the first data track. A second codeword sequence is generated for the second data sequence based on the first codeword sequence on the first data track, and the second codeword sequence is written to the second data track of the recording media.

Modulation coding for two-dimensional recording

Data format that allows for format-efficient data storage, particularly on bit-patterned media. The data format allows for variations in the data storage device, such as reader-to-writer gap variations. A medium can also have at least a pair of a synchronization field and a quiet field with a length greater than a length of the synchronization field. These can be implemented in a bit patterned media system.

Growing community of inventors

Eden Prairie, MN, United States of America

Barmeshwar Vikramaditya