Discovision Associates

Seagate Technology Incorporated

Laser Magnetic Storage International Company

Lsi Logic Corporation

Applied Magnetics, LLC

David L Schell

David E Lewis

Kurt W Getreuer

Marvin B Davis

Leonardus J Grassens

Randolph Scott Crupper

Johannes J Verboom

Chris Thomas Settje

LingZhi Yang

Kevin G Christian

Steven Alan Koldewyn

Gregory V Hofer

Timothy Francis Ellis

Robert A Alt

Beng Wee Quak

Abhay Tejmal Kataria

John Charles Purkett

Reed David Hanson

James C McDonald

Peter John Windler

Steven Schauer

Teck Khoon Lim

Thomas C Zirps

Ming Zhong Ding

Alan D Poeppelman

Patrick TaiHeng Wong

Daniel Eugene Hobson

Sandeep Dominic Sequeira

Christopher Thomas Settje

KarWei Koay

Soon Wah Leow

Henk A Van Der Put

Pierre R Sonneville

Mike E Baum

Leonardus I Grassens

Marinko Bosnich

Kathleen M Connelly

Cees Van Nimwegen

Kenton J Pharris

Kar Wei Koay

Apparatus and method for mitigating impedance changes in a microactuator conductive joint. In accordance with some embodiments, a microactuating element has a conductive input junction, the junction having dissimilar metals in contact with one another. The microactuating element is adapted to mechanically deform to displace a control object responsive to a micractuation control signal that is applied to the junction. A control circuit applies a bi-directional transition signal to the conductive input junction to reduce an increased impedance of the junction.

Impedance mitigation of a microactuator conductive joint

One illustrative embodiment of the present invention pertains to a device. The device is configured to evaluate a Gray code value and to provide compensation for error in the Gray code value. Another illustrative embodiment of the present invention pertains to a method. The method includes comparing Gray code information with servo information. The method also includes evaluating error in the Gray code information based on the comparison between the Gray code information with servo information. Another illustrative embodiment of the present invention pertains to a data storage system. The data storage system includes a data storage medium, a head, and a controller. The head is controllably positionable relative to the data storage medium. The controller includes a means for sensing position information from the head. The controller also includes a means for compensating for error in the position information, to position the head relative to the data storage medium. Embodiments of the present invention provide unforeseen and inventive advantages over conventional data storage systems, including by assuring superior position evaluation and control of a read head relative to a data storage medium.

Controller with fractional position algorithm

A method of calibrating an actuator controller is discussed. The method includes using an open loop seek operation and compensating for a low frequency response to reduce the velocity at the end of the open loop seek operation.

Open loop Ka calibration with low frequency compensation

Various embodiments are generally directed to moving a control object using a sine-based trajectory profile with an initial non-zero velocity.

Trajectory control profile with non-zero initial velocity

Using a 'reference' sensor, a reference position is detected in a frame of reference that is moving along a predetermined path relative to the reference sensor. The reference position is used to derive a position-dependent indicator of a position-dependent 'longitudinal' offset component (i.e. along the path). An output from the target sensor is monitored using a &#x201c;target window&#x201d; that is partially based on the position-dependent indicator.

Monitoring a sensor's output using a target window that is based on a longitudinal offset's position-dependent indicator

The present invention is a method and system for reducing miscorrections of data in a post-processor. In an embodiment of the invention, the system and method may compare a result of an exact match function and a metric for each row of a reconstructed data block to determine if a correction should be made. An algorithm for performing an exact match function may include a column parity check syndrome, a matched filter error syndrome, and an error mask of the present invention. If a result of an exact match function is an exact match, a priority of correction may be given to the row in which the exact match was produced.

Method of reducing miscorrections in a post-processor using column parity checks

An apparatus and method for selecting physical cylinders (cylinders accessible for read/write operations) in a disc drive is provided. The disc drive includes at least one rotatable disc. The disc drive also includes a first head, which is positionable adjacent a first disc surface, and a second head, which is positionable adjacent a second disc surface. The first disc surface has a first plurality of greycode tracks and the second disc surface has a second plurality of greycode tracks. Each greycode track of the second plurality of greycode tracks corresponds to a different greycode track of the first plurality of greycode tracks, thereby forming a plurality of greycode cylinders, with each greycode cylinder of the plurality of greycode cylinders including a pair of corresponding greycode tracks. The physical cylinders are a subset (less than all) of the plurality of the greycode cylinders. The method of selecting the physical cylinders includes determining whether the first plurality of greycode tracks or the second plurality of greycode tracks demonstrates greater track eccentricity, to thereby obtain a maximum track eccentricity surface and a corresponding maximum eccentricity head. The maximum track eccentricity surface is one of the first and second disc surfaces and the maximum eccentricity head is a corresponding one of the first and second heads. The maximum eccentricity head is used to locate at least one of the physical cylinders.

Selecting physical cylinders in a disc drive employing discs with pre-written servo patterns

An apparatus comprising a sampler circuit and a filter circuit. The sampler circuit may be configured to generate a digital signal in response to a pre-amplified signal. The filter circuit may be configured to generate a track ID signal in response to the digital signal. The filter circuit may also be configured to (i) improve or increase signal-to-noise ratio (SNR) and (ii) reject DC offset errors.

Filter for disk drive bi-phase servo demodulation

An apparatus and method for dynamic head switch timing recalibration are provided. With the apparatus and method, a determination is made as to whether a difference in a reference head switch timing and the head switch timing at a later time is sufficient to meet a certain criteria. If the difference meets the criteria, a recalibration of the head switch timing is performed. For example, in a preferred embodiment, the criteria is a number of address mark (AM) misses during a head switch operation. If this predetermined number of AM misses is detected, then it is determined that a recalibration is necessary since the predetermined number of AM misses is an indication that the head switch timing has changed significantly from the reference head switch timing.

Dynamic head switch timing recalibration apparatus and method

An order in which bits for serial data are transmitted or received by a first device, integrated circuit (IC) or logic, is programmable to be either from most significant bit (MSB) to least significant bit (LSB) or from LSB to MSB. Therefore, when the first device is used with a second device, integrated circuit (IC) or logic, which can handle the serial data in only one order, the first device is programmed, or configured, to handle the serial data in the same order as the second device.

Programmable bit ordering for serial port

A circuit generally comprising a first circuit and a phase lock loop. The first circuit may be configured to (i) collect a plurality of samples per cycle during a plurality of cycles of an input signal and (ii) calculate a phase offset and a frequency offset for the input signal relative to a clock signal in response to the samples. The phase lock loop may be configured to (i) preset a phase error signal to the phase offset and a frequency error signal to the frequency offset and (ii) generate the clock signal in response to the phase error signal and the frequency error signal.

Zero phase and frequency restart PLL

An optical disc system for storing information on a medium includes a light source, a focusing mechanism, and a tracking mechanism wherein the mechanisms are controlled by a feedback loop and the focusing mechanism focuses light emitted by the light source onto the medium to effect writing of information thereon. The system is provided with an electronic circuit for generating a servo error signal that is communicated in the feedback loop for effecting corrections of the focusing mechanism and the tracking mechanism. The system is further provided with a driver for energizing the light source, a bias coil disposed proximate to the medium, a bias coil driver switchably connected to the bias coil for supplying an electric current thereto, a current monitoring circuit connected to the bias coil driver having an output responsive to the electric current, and a controller connected to the output of the current monitoring circuit and to the driver. The controller thereby enables the driver when the output of the current monitoring circuit exceeds a predetermined magnitude so that information processed through the focusing mechanism is written onto the medium when the electric current flowing in the bias coil exceeds a threshold.

Optical disc system and method for controlling bias coil and light source to process information on a storage medium

An analog to digital circuit assembly includes a circuit for multiplexing a reference voltage input of an analog to digital converter to produce alternating normalized and referenced digital outputs of an analog signal input at a rate controlled by a sampling clock which includes a switch including first and second inputs, an output, and a control input for alternately connecting the first and the second inputs to the output, the output being applied to the reference voltage input. An information detection device having a detection output and a servo mechanism that controls operations on detected information is provided in conjunction with a signal summing circuit, a direct current voltage reference, a control clock connected, a servo error signal circuit having a servo error signal output and input, a sampling clock, and a processing circuit having an input connected to a digital output of the analog to digital converter and an output for controlling the servo mechanism. The analog to digital circuit assembly is also implemented in an optical disc system for improved operation thereof.

Analog to digital converter assembly for normalizing servo error signals and multiplexing reference voltage inputs and digital outputs and improved optical drive system including same

An optical drive system includes a computer that monitors the current in an improved bias coil assembly in conjunction with a magnetomotive field generator to determine when a predetermined current threshold is exceeded. The bias coil assembly includes a wire coil wrapped around a center bar contained by a bias coil housing. The bias coil assembly is positionable above an information storage medium so that the entire medium may be within the magnetic field thereby allowing writing of information to all portions of the medium. When the threshold is exceeded, a sufficiently strong magnetic field is generated to permit writing of information on the storage medium utilizing a laser. A laser pulse generator is then enabled. The device thereby achieves a substantially shortened write cycle while employing the improved bias coil assembly.

Optical disc system having current monitoring circuit with improved bias coil assembly and controller for laser driver and method for operating same

An optical drive system includes a computer that monitors the current in the bias coil of a magnetomotive field generator to determine when a predetermined current threshold is exceeded. When the threshold is exceeded, a sufficiently strong magnetic field is generated to permit writing of information on a storage medium utilizing a laser. A laser pulse generator is then enabled. The system is provided with an optics module for processing light produced by the laser light source. A laser driver for energizing the laser light source is positioned in close proximity to the optics module and the laser light source to reduce noise in signals associated with the optics module. The system thereby achieves a substantially shortened write cycle while reducing relevant signal noise.

Optical disc system including current monitoring circuit assembly having controller with improved optics module and laser driver and method for operating same

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Colorado Springs, CO, United States of America

David L Schell