Seagate Technology Incorporated

Seagate Tech. LLC

Daniel Scott Fisher

Stanton MacDonough Keeler

John A Mount

Steven Scott Williams

Robert Dale Murphy

Edward Sean Hoskins

Mike Propps

A disc drive includes a base and a disc rotatably attached to the base. A controller for a disc drive uses a system for mapping logical block addresses to actual location on a disc drive stores the number of skipped or defective sectors which occur prior to a target cylinder in a cylinder skip table. The system estimates a starting cylinder location for the selected logical block address. After estimating the cylinder location, a number of skipped defective sectors that have occurred prior to a cylinder start is determined. The starting location of the cylinder is slipped by this amount. A target track and associated head is also determined. Information in the track identification field is used to adjust the actual location on the track and to determine if a track seek to another track is needed.

Full slip defect management system using track identification

A method and system of identifying and compensating for the cumulative effect of once per revolution, OPR, timing errors by modulating the size of an inter-sector runout (ISR) field between servo sectors. The ISR field is part of an inter-sector gap (ISG) field. The method begins when the nominal data field frequency is increased by one-half of the spin speed tolerance to guarantee adequate data field tolerances at the fastest portion of the timing OPR error curve. The ISR field is added to the disc format and maintained as a rotationally varying field. The ISR field is varied rotationally from a minimum of zero to a maximum equal to the timing OPR error tolerance. The size of the ISR field is varied rotationally based upon a calibration table that is used to identify the location of the disc drive head and to compensate for the appropriate timing OPR error at that location. The remainder of the ISG field is used to compensate for fixed timing errors.

Variable format timing runout compensation

A single chip integrated disc/servo controller and processor (CPU) for a disc drive reduces timing overhead associated with processor/controller/memory communication paths, increases speed, reduces the number of ASIC components, and increases reliability. The processor has a core that can be customized and implemented with appropriate hard disc drive specific controller technology including code or algorithms. Timing overhead associated with the conventional multi-chip communication paths is reduced by the inventive structure as the single on-chip processor has direct access to a buffer memory through a buffer manager within the controller logic. This eliminates the pin and pad delays that are present in conventional implementations. This performance increase has a direct positive impact on disc drive performance generally, and more particularly on disc drive performance when running code from the buffer memory. The structure and method also reduce overhead when communicating with the controller logic, and reduces the delays and other timing overhead associated with accesses to individual storage registers, which are generally slower in the conventional multi-chip configuration than in the single-chip integrated device. Single-chip integration also advantageously reduces product cost by removing one of the ASICs that would otherwise be required for the disc drive electronics. The single chip integration provided by the invention also advantageously includes structural features implemented in sub-micron semiconductor manufacturing technology to provide the aforementioned integration.

Integrated controller/processor for disc drive having direct memory

A data sector/servo split generator is disclosed for a disk drive apparatus implementing a zone bit recording format and having an embedded sector servo system where servo sector fields split at least one data field on a surface of a disk in the disk drive apparatus. A first counter is provided to count an amount of time to the beginning of a data field, and a first signal (SECTOR) is generated to indicate when the beginning of a data field is encountered by a read/write head in the disk drive. A second signal (SPLIT.sub.-- VALID) is generated by the data sector/servo split generator if a next data field after the generation of the SECTOR signal is split by a servo sector field. A second counter counts a predetermined number of data bytes transferred between a surface of a disk in said disk drive apparatus and said disk controller, so that a third signal (SPLIT) is generated, the SPLIT.sub.-- VALID signal is generated, when a servo sector is encountered in a data field by the read/write head. The SECTOR and SPLIT signals are supplied to a disk controller which uses those signals to control the transfer of data to and from the disk.

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Longmont, CO, United States of America

Daniel Scott Fisher