Rigidyne Corporation

Seagate LLC

Haim Nissimov

LeRoy A Volz

Le Roy Volz

A thermal offset compensation system is provided for use in a computer disk drive unit have a dedicated servo surface on one of a plurality of memory storage disks. The disk drive unit has a plurality of electromagnetic heads displaced as a group relative to respective storage surfaces on the disks to read and/or write data in concentric tracks. One of the heads comprises a servo head for reading servo data prerecorded onto the dedicated servo surface to align the remaining heads relative to corresponding cylinders of data tracks. Thermally induced offsets of the data heads relative to the servo head are measured on one or more calibration cylinders located in the inner and outer guard bands of each storage surface. The average offset of the data heads, taken collectively, is determined and subsequently compensated-for when any data head is utilized to read or write data on a selected track. The thermal compensation offset is determined during a spin-up operation of the disk drive unit, and then periodically thereafter upon receipt of any host command by the disk drive unit.

Thermal offset compensation for high density disk drives

An adaptive velocity profile system is provided for variably controlling a disk drive head in a computer disk drive or the like, to obtain substantially minimum seek times in accordance with variable operating conditions. The system monitors actual performance of the head in the course of a seek step during which the head is displaced relative to a memory storage disk for alignment with a selected track on the disk, and wherein the head performance is variable in response to a range of parameters such as temperature, power supply voltage, mechanical stiffness, etc. The monitored head performance as represented, for example, by head acceleration at the initiation of a seek step and/or by a track address mismatch at the conclusion of a seek step is used, in the preferred form, to select an appropriate one of several available velocity profiles for controlled head deceleration at the conclusion of a subsequent seek step. The selected velocity profile is chosen for obtaining the fastest possible seek times consistent with current operating conditions.

Adaptive velocity profile system for a disk drive head

An offset nulling system is provided for use in computer disk drives to identify and compensate for actuator head position offset errors attributable to dc offsets of the disk drive control circuitry, thereby obtaining improved head alignment wiht a designated track on a memory storage disk or the like. The system includes a microcontroller adapted during a calibration mode to identify the position offset error and direction for selected tracks located respectively at radially inner and radially outer regions of the disk, and to adjust head position incrementally relative to those tracks to subsantially eliminate position offset error. Thereafter, during a normal operation mode of the disk drive, the microcontroller functions at the conclusion of a track seek step to adjust the head through a position offset compensation value and direction derived by interpolation of the position offset compensation value and direction identified during the calibration mode, in accordance with the specific track address.

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West Hills, CA, United States of America

Haim Nissimov