Abstract: A RAID-1 system achieves sparing by allocating 1/(2N?1) of each storage device as a spare region, in a mirrored RAID-1 system having N pair of mated devices. The remaining portion of each device is partitioned into (2N?2) data partitions. If a device fails, the contents of its mate are copied into the spare regions of the other devices. This preserves fault tolerance even if a second device subsequently fails.

Abstract: A disk drive, a servo controller, and a controller which have realized high-degree control by lightening processing load to a microprocessor unit (MPU) without increasing cost is disclosed. An analog/digital (AD) converter (ADC) performs the AD conversions of the regenerated levels A, B, C, and D of burst patterns supplied from a channel and retains the converted levels in an ADC register. A servo assist (SA) computes parameters, such as the position error of a head, independently of an MPU, based on the regenerated levels of the burst patterns retained in the ADC register and an instruction from the MPU retained in a SRAM. Based on the computed parameters, the SA computes servo data (DACOUT) for driving a voice coil motor and supplies the servo data to the DAC section of a VCM driver section through a SIO.

Abstract: To optimize the life of a magnetic disk data storage device it is recognized that the accessing of data on the disk data surface should mimic the varying effective lubricant protection over the disk surface. The lubricant applied to the disk data surfaces migrates outward during drive operation. To match the disk surface protection to the frequency of data accesses at the storage locations, the stored data files are periodically examined to determine how recently access has occurred and the number of accesses during a most recent fixed period to determine whether the data file is to be stored in radially inner or radially outer portions of the band of concentric data tracks. By thus allocating the data file storage location, the data is accessed and intermittent contact between disk surface and transducer carrying slider occurs with greatest frequency where the lubricant coating is least depleted and most robust.

Abstract: A method and apparatus for estimating the value of a slider airbearing resonance frequency involves obtaining a readback signal from a data storage medium over a plurality of complete airbearing periods and estimating the value of an airbearing resonance frequency using the readback signal. In one embodiment, a discrete signal segment comprising a plurality of frequency transform components is produced using the readback signal information, and the value of the airbearing resonance frequency is estimated using spectral leakage in the discrete signal segment. A ratio of the magnitudes of a first DFT component to a second DFT component is computed at each of a plurality of sampling rates. Each of these sampling rates is defined by a number of samples per average airbearing cycle multiplied by a frequency falling within a range of expected airbearing frequencies associated with a given implementation.

Abstract: A magnetoresistive read/inductive write magnetic head assembly formed on a hard electrically insulating substrate and having electrostatic discharge protection comprises: a hard electrically insulating substrate, preferably formed of sapphire or alumina-TiC; multiple alumina layers formed over the substrate; a magnetoresistive read/inductive write head positioned between the alumina layers; a silicon layer supported by the substrate; and a semiconducting circuit integrated into the silicon layer and interconnected with said magnetoresistive read/write inductive write head to provide electrostatic discharge protection to the head. The silicon layer may be epitaxially grown on the substrate when implemented as sapphire, or bonded to the substrate when implemented as alumina-TiC. The hard electrically insulating substrate and alumina layers provide the assembly with a hard air bearing surface having generally uniform lapping and etching characteristics, and excellent durability.