Maxtor Corporation

Seagate Technology Incorporated

Christine Green

Edward Charles Gage

Tim Rausch

Housan Dakroub

Richard Edward Martin

Robert Dean Turner

Curtis W Egan

Jerry Moline

Rajita Shrestha

Stephen H Perlmutter

Devon Dallmann

A circuit may be configured to reduce the power consumption and extend the life of a near field transducer of a heat-assisted magnetic recording (HAMR) device by pulsing a laser. The current that drives the laser may be of a frequency and magnitude so as to approximate the value of a continuous current in a continuous, non-pulsed laser. A system on chip (SOC), which may include a HAMR channel, can generate a laser data signal that may be synchronous with, and offset from, a write signal by a certain period of time, and may calculate certain parameters such as peak current and pulse width that may be applied to the signals in a preamp. The preamp signals can be used to program data to a disc medium.

HAMR channel to preamp interface

Data recovery, following a read error in a hard disk drive, is provided which includes an adjustment of fly height. In one embodiment, some re-reads are performed by both adjusting the fly height and the off-track positioning of the read head. In one embodiment, two or more fly heights are normally used during read/write operations such as in a zoned manner, and adjustments to fly heights are performed with respect to the fly height for the zone where the error occurred.

Hard disk drive fly height adjust method and apparatus during error recovery

In some embodiments of the present invention, a disk drive includes a rotatable data storage disk, a head, and a controller. The head is configured to fly on an air cushion relative to a data recording surface of the rotating disk while writing data to the data recording surface responsive to a write command from a host device or while reading data from the data recording surface to generate a read signal responsive to a read command from the host device. The controller is configured to measure flying height of the head relative to the data recording surface of the disk in response to sensing power-up of the disk drive and/or a shut-down command from the host device. The controller may measure the flying height in response to sensing power-up of the disk drive and, subsequent to measuring the flying height, may generate a ready signal to the host computer that indicates that the disk drive has powered-up and is ready to receive read/write commands from the host computer.

Methods and disk drive that measure head flying height at power-on/off

Methods and structures for a general purpose, discrete time sample, interval accumulating filter for measuring any of a plurality of parameters associated with operation of a digital read channel. The general purpose interval accumulating features and aspects hereof permit flexible configuration for measuring a variety of operational characteristics and parameters of a digital, discrete time sample, read channel. The interval accumulating filter may sense harmonic frequencies associated with mechanical and electrical noise in the read channel operation. Other features and aspects hereof permit monitoring of multiple signal frequencies of a read channel in a disk drive, error recovery of a bad sector in a disk drive, and measurement of numerous other operational aspects of a discrete time digital sample read channel.

Methods and structure for general purpose interval accumulating filter for measuring operational parameters of a digital read channel

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Longmont, CO, United States of America

Christine Green