International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Universiti Brunei Darussalam

Anthony Paul Praino

Timothy Joseph Chainer

Mark Delorman Schultz

Bucknell Chapman Webb

Edward John Yarmchuk

Mark E Re

David William Abraham

Hemantha Kumar Wickramasinghe

Lloyd Alan Treinish

James Peter Cipriani

Younghun Kim

Ildar Khabibrakhmanov

Gordon James Smith

Hal Hjalmar Ottesen

Philip Louis Trouilloud

Yogish Sabharwal

Suryanarayan G Hegde

Shinji Takayama

Muthuthamby Sri-Jayantha

Bernell E Argyle

Vaibhav Saxena

Thomas George

Saiful A Husain

Rashmi Mittal

Steven J Root

Rudolf Schafer

A set of characteristics of a period is extracted from a forecast that is applicable to the period and a geographical area. From a repository, a set of historical data is selected corresponding to a historical period, the set of historical data including a historical forecast related to the geographical area, and an actual measurement of wind at a location in the geographical area, the set of historical data having a subset of the set of characteristics. From the set of historical data, a function is computed to represent a discrepancy between the historical forecast and the actual measurement over the historical period. A bias value is computed from the function. By applying the bias to a value in the forecast, an adjusted forecast is produced of winds at a wind turbine located at a location in the geographical area.

Temporal bias correction in wind forecasting

Methods and arrangements for automating weather model configurations. Characteristics of a target geographical area are received, as are a plurality of existing weather model configurations which are implemented for undertaking weather modeling in other geographical areas. A subset of the existing weather model configurations is selected, the subset comprising configurations corresponding to geographical areas having characteristics similar to the characteristics of the target area. A weather model is run with respect to each configuration in the subset of existing weather model configurations. Based on the running of a weather model with respect to each configuration, an output set of weather model configurations is selected for undertaking weather modeling in the target area.

Automating weather model configurations

Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device. The location of another trigger pattern to be written is shifted, using the measured time interval to determine the shift in location for the another trigger pattern.

Method and apparatus for correcting for systematic errors in timing pattern generation

A disk drive which incorporates separate actuators for each recording head so as to only place required recording heads over the recording media of multiple surface hard disk drives. The reduction in recording heads that are placed over the recording media reduces drag on the rotating disk holding the recording media and thereby reduces the power consumption. Reducing the number of recording heads over the recording media also reduces damage to the recording media surfaces in the event of a physical shock to the drive since inactive transducer heads are not in a position to damage the recording media.

Low power hard disk drive using multiple, individually controllable actuators

Improvements in placement of timing patterns in self-servowriting include correcting for systematic errors due to geometric effects. A correction is made for varying systematic errors, such as when the recording head has spatially separate read and write elements. Further, servopattern rotation due to residual or unmeasured systematic errors is reduced by using a once per revolution clock index derived from the motor drive current waveform or any other sensor. In one aspect of correcting for systematic errors in the writing of timing patterns on a storage medium of a storage device, a time interval between a trigger pattern written at a first-radial position of the storage medium and a rotational index is measured. The rotational index is related to the rotational orientation of the storage medium with respect to a fixed frame of the storage device. The location of another trigger pattern to be written is shifted, using the measured time interval to determine the shift in location for the another trigger pattern.

Method and apparatus for correcting systematic errors in timing pattern generation

An apparatus and method for reading an information signal from a magnetic storage medium using a magnetoresistive (MR) head, and separating a thermal signal component and, if present, a magnetic signal component from the information signal. A signal separation/restoration module eliminates distortion in the magnetic signal component of a readback signal induced by a thermal signal component of the readback signal. A finite impulse response (FIR) filter may be employed in the signal separation/restoration module to eliminate the distortion in the magnetic signal. The signal separation/restoration module may be employed to extract the thermal signal component from the readback signal. In one configuration, an MR head is coupled to an arm electronics (AE) module, having a highpass filtering behavior, and a signal separation/restoration module that includes an inverse filter having a transfer function inverse to that of the effective highpass filter of the AE module. The inverse filter may be an infinite impulse response (IIR) filter. In another embodiment, the magnetic and thermal signal components of a readback signal are respectively extracted and processed so as to linearly correspond to head-to-disk spacing. Head-to-disk spacing change using the thermal signal is used to detect disk surface defects, topographic variations, and servo control surface variations.

Method and apparatus for separating magnetic and thermal components from

Improvements in placement of timing patterns in self-servowriting include correcting for random errors. Random errors may be caused by variations in disk velocity and therefore, one technique for correcting for random errors includes reducing velocity jitter. Additionally, random errors can be corrected by improving interval control during the propagation of trigger patterns used in writing timing information on storage media. Further, random errors, in the writing of timing information, can be corrected during a single revolution of the storage media. This eliminates additional rotations, thereby providing a large capital cost savings.

Method and apparatus for correcting for random errors in timing pattern

A method and apparatus for accessing a data storage medium having raised and lowered portions indicative of data stored on the medium. Energy is supplied to a sensor which is moved relative to, and in close proximity to, a surface of the medium on which the data in the form of raised and lowered portions is stored. The sensor and the storage medium are moved in relation thereto, such that the sensor remains at a substantially constant fly spacing therefrom. A decrease in temperature of the sensor is detected when it is in proximity to a variation, i.e., a raised portion on the medium. This detected decrease in temperature associated with a raised variation, e.g., asperity, can be used as the basis upon which to detect the data on the data storage medium. The data storage medium may also contain magnetically stored data, such that the surface variations and the magnetic characteristics of the data storage medium can both be utilized to store data thereon.

Method and apparatus for data storage using thermal proximity imaging

Improvements in placement of timing patterns in self servo writing include correcting for random and systematic errors due to geometric effects. In a disk drive having a recording head with separate read and write elements, a method for determining separation between the elements and for correcting for such errors as a function of skew angle between the head and the disk. Errors resulting from misalignment and non-parallelism of the elements as well as misalignment of the head on it its actuator are also detected and corrected. Errors due to changes in rotational velocity of the disk and misplacement of timing patterns with respect to adjacent timing patterns are detected and corrected. In general, a single revolution process may be used to both write and detect random errors on each track and corrected on subsequent tracks.

Method and apparatus for determining separation between read and write

Method and apparatus for determining systematic errors

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Poughquag, NY, United States of America

Anthony Paul Praino