Seagate Technology Incorporated

Maxtor Corporation

Roger J Kassab

Ghassan M Abdelnour

Richard E Olsen

A fly height controller that controls fly height of a read/write head relative to a rotating data storage disk is calibrated. A heater signal is applied to a heater element to heat the head. The level of a write current that is conducted through the head is increased until the head contacts the disk. The fly height controller is calibrated based on at least a first level of the heater signal and a first level of the write current when the head contacts the disk.

Fly height calibration for read/write heads

A disk drive includes a rotatable data storage disk, and head, a controller, and a preamplifier. The head is configured to write data to and read data from the disk. The controller is configured to generate a write current command. The preamplifier includes a plurality of write current parameters, and is configured to select among the plurality of write current parameters based on the write current command from the controller, and to generate a write current having a shape that varies based on which of the write current parameters are selected. The write current is provided to the head to write a plurality of data bits on the disk.

Disk drive partially autonomous preamplifier for write current parameters

Method for optimizing parameter values in a read/write channel of a disc drive. A population of error rate points is obtained from selected ranges of a plurality of read/write channel parameters, each error rate point corresponding to a unique combination of parameter values and having an associated error rate value. A weight is determined for each of the error rate points through normalization to the minimum error rate value in the population. A threshold value is determined based upon the error rate values in a plurality of nominally identical disc drives and the weights are compared to the threshold value. Those error rate values having weights less than the threshold are selected and a center of gravity is determined therefrom. At such times that the entire population of error rate values has weights greater than the threshold value, the optimum parameter values are those that map to the center of gravity. Otherwise, for each error rate value having a weight greater than the threshold, the average and standard deviation are determined for neighboring (immediately adjacent) error rate values and the error rate value having the tightest distribution in the neighboring error rate values provides the optimum parameter values.

Selection of optimal read/write channel parameters in a hard disc drive

A method for optimizing the write current used by a disc drive read/write transducer to write data to data tracks on a disc. The method optimizes the write current by selecting write currents that minimize the occurrence of repeatable, hard read errors. The method comprises writing a predetermined pattern of information to selected data tracks using each of a plurality of write current values and subsequently reading the data on the selected data track while recording the number of hard read errors for each of the write current values. The optimum write current value is selected at the write current value having the minimum number of hard read errors. An optimum write current value is determined for each of a plurality of locations on the disc and these write current values are stored in the disc drive. During subsequent disc drive write operations, these values are used to determine the optimum write current value for a selected data track through interpolation techniques. Alternatively, for disc drives employing zone-based recording, an optimum write current value can be determined and used for each zone of data tracks on the disc.

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Shrewsbury, MA, United States of America

Roger J Kassab