International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies B.v.

Roger F Hoyt

Steven Robert Hetzler

Mario Blaum

Jaishankar Moothedath Menon

John Stewart Best

Steven Edward Millman

Carl Michael Jefferson

Michael F Mitoma

Todd G Culman

Geometrically-dependent error rates are used to identify sectors for XORing data in a RAID system for parity purposes in such a way that the probability of failure of any particular group is minimized.

RAID system using regional error statistics for redundancy grouping

An active noise reduction system for reducing the acoustic noise generated by a hard disk drive or generated external of a hard disk drive. The active noise reduction system is integrated into the hard disk drive and produces an acoustic waveform that is 180 degrees out-of-phase with the acoustic noise being generated, for example, by the spindle motor and VCM. The acoustic noise is received directly through a microphone or indirectly through the read/write head, spindle motor driver, or VCM driver. The acoustic noise is processed by electronics and the noise canceling waveform is either retrieved from the hard disk drive's memory, disk, or generated by the electronics. The noise canceling waveform is then broadcasted through one or more transducers that are integrated in the hard disk drive.

Hard disk drive with self-contained active acoustic noise reduction

An apparatus and method for a low power consuming disk drive unit comprising multiple HDD subsystems having spindles and associated disk platter(s) supported thereon, read-write heads and actuators for positioning the read-write heads. The disk platter(s) of each HDD subsystem may differ in diameter, rate of rotation and formatting. The method by which the disk drive unit operates to reduce the power requirements of the disk drive unit is to have the controller selectively power the smaller/more efficient HDD subsystem the majority of the time to store frequently accessed information and not to power the multiple larger/less efficient HDD subsystems that store the less frequently accessed information, thereby achieving reduced power needs for the disk drive unit.

Apparatus and method for low power HDD storage architecture

A method for operating a synchronized array of fixed block (FBA) formatted Direct Access Storage Devices (DASDs) to store and update variable-length (CKD) formatted records. This method is suitable for use with DASDs that obtain high recording density by using read and write head technology requiring 'micro-jogging' to adjust for differing read and write head alignment or banded disk architecture having a higher block count in the outer tracks than in the inner tracks. Magneto-resistive heads may require micro-jogging to realign the write head for recording after reading the physical track location. The invention employs a DASD staggered array architecture having logical tracks consisting of diagonal-major sequences of consecutive blocks arranged in a predetermined wrap-around manner such as a topological cylinder or torus. The minimum necessary number of DASDs (N) in the staggered array is limited by the fixed block size (B), the interblock gap size (G), the average DASD data transfer rate (D), and the micro-jog delay time (T). A (N+1).sup.th DASD may be added to record the parity of each diagonal-major sequence for improved fault-tolerance.

Efficient variable-block data storage system employing a staggered

A self-diagnostic method and apparatus is described for indicating the likelihood of an impending crash of a magnetic transducer or head with a rotating magnetic medium by dynamically and periodically calculating overwrite efficiency for performing a desired control operation when it exceeds a preselected value denoting dangerous proximity of the transducer to the surface of the medium.

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San Jose, CA, United States of America

Roger F Hoyt