Seagate Technology Incorporated

Siew Kin Chow

Alfredo Sam Chu

Wenzhong Zhu

Kenneth A Haapala

Franklin P Martens

Paul William Burnett

Scott Edward Ryun

Jason Matthew Feist

Dallas S Holm, Jr

YeongHeng Tan

Data is written to a recording medium via a read/write head. Subsequent to the writing, the data is read via a read transducer of a read/write head. An instability indicator is derived based on measurements performed while the reading the data. If the instability indicator exceeds a threshold, a current applied to a write coil of the read/write head is changed for subsequent write operations.

Changing write coil current in response to reader instability

An operational laser power for a heat-assisted, magnetic recording head is selected based on a function of a write quality metric versus laser power. The write quality metric of data written to a magnetic recording medium is monitored at the operational laser power. Responsive to the write quality metric satisfying a threshold, a power difference between the operational laser power and an offset laser power is determined. The offset laser power corresponds to a point of the function where the write quality metric is approximately equal to the threshold. A maximum laser power is set for a calibration operation. The maximum laser power is based on the sum of the operational laser power and the power difference.

Selecting a maximum laser power for a calibration based on a previously measured function

A first tone is written at a first frequency to outer tracks that surround an inner track of a magnetic recording medium. A second tone is written at a second frequency different from the first frequency to the inner track. The first and second frequencies are both lower than a frequency of an AC erase signal. A crosstrack profile of the inner track is determined based on reading amplitude of the second frequency via the read/write head.

Method and apparatus for writing test tracks on a magnetic recording medium

A system may have a data storage medium that contains at least one data bit that is accessed by a transducing head that has a near-field transducer. A controller can be connected to the transducing head and store a plurality of near-field transducer operating currents in a memory. The controller may identify a change in efficiency of the near-field transducer from the plurality of near-field transducer operating currents.

Near-field transducer efficiency monitoring system

A pattern is written to only a portion of a test track of a magnetic disk. The pattern written to the portion of the test track is read using a read head. A cross-track offset between the read head and a write head is determined at a position on a disk based on reading the pattern.

Determination of reader to writer crosstrack offset via a magnetic disk

A data storage device, e.g., a disc drive, includes one or more heads including a transducer. Each head also includes a deformable material that allows the spacing adjustments between the transducer and a data storage medium, e.g., a data storage disc, according to each of a plurality of settings. The device calculates a response function of a spacing change to a setting change for each head by measuring a change in the pole tip-data storage medium spacing corresponding to at least two settings. The device also determines an optimal setting. The device may also repeat response function calculations and/or determination of optimal settings to ensure continued optimal performance of the device. In summary, the device sets an optimal setting for each head according to a calculated response function particular to each head.

Transducer-data storage medium spacing adjustment

The present invention is directed to detecting amplitude modulation on the written signal as a result of head movement along the z-axis during the write operation, before the head has had sufficient time to stabilize after seeking from a different track.

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Shakopee, MN, United States of America

Siew Kin Chow