Quantum Corporation

Plus Development Corporation

Bruce R Peterson

William G Moon

Michael G Machado

James H Do

Hung C Nguyen

Thomas R Stone

Ronald R Moon

Clifford M Gold

Randolph H Graham

William N Thanos

Richard J Blackborow

Daniel E Barnard

Joshua Lindsay

Joel N Harrison

Thomas A Tacklind

Donald V Daniels

James A Henson

Donald C Westwood

Thomas D Howell

Tim R Glassburn

James P McGrath

Michael L Raab

Ashraf I El-Sadi

Don Rowe

A start-up routine for a brushless sensor-less DC motor inductively measures motor position angle rather than motor start phase and inductively calculates an acceleration trajectory based on motor position rather than motor parameters. Motor position angle is determined by measuring the rise time of each phase, computing sinusoidal components for each phase, then calculating the angular position based on the sinusoidal components. The acceleration trajectory is determined by computing time delays for each phase. To do this, angular acceleration of the motor is calculated by determining the change in angular position of the motor between two predetermined time intervals. The motor may then be spun up with a start-up routine that is not dependent on motor parameters, resulting in a more efficient and consistent performance.

Start-up algorithm for a brushless sensorless motor

A programmable data sequencer transfers fixed length data blocks between variable length storage segments of a magnetic storage disk and a buffer memory within a data storage device. The data sequencer includes a stack memory for holding user byte count values read from a header field preceding each data sector having variable length split storage segments. Each byte count value indicates respective length of a following variable length storage segment, so that the storage capacity of each segment is dynamically determined by the data sequencer in real time by popping the user byte count value from the stack into a storage segment length counter and by counting down the count value within the segment length counter.

Miniature disk drive having embedded sector servo with split data fields

An improved disk drive architecture includes a microcontroller interface circuit connected between a drive microcontroller and a buffer controller. The microcontroller interface circuit includes address mapping registers for mapping at least one predetermined portion of directly addressable memory of the microcontroller to address locations of the drive's cache buffer. The buffer controller circuit includes an access arbitration circuit for arbitrating requests for access to the cache buffer by the drive's data sequencer, the drive's host interface controller and the drive's microcontroller. A microcontroller wait state generator responds to the access arbitration circuit by generating and applying a wait state sequence to the microcontroller until a request it makes for access to the cache buffer can be executed.

Shared memory array for data block and control program storage in disk

An improved cross-checking circuit is provided for use within a Reed-Solomon error correction and cross checking apparatus for performing error correction and cross checking upon a data block within an incoming stream of substantially contiguous data blocks flowing from a source to a destination. The circuit is based upon a distinguished primitive element, alpha.sup.1 (2B (Hex))=x.sup.5 +x.sup.3 +x+1, of a Galois field whose elements are represented by residue classes of binary polynomials modulo p(x)=x.sup.8 +x.sup.4 +x.sup.3 +x.sup.2 +1. The apparatus includes a microcontroller for supervising the flow of the data blocks and for making calculations related to error corrections, and a Galois field syndrome generator and remainder recovery circuit is connected to receive the incoming stream and recover therefrom plural error correction remainder bytes for each block and selectively to hold said bytes in a syndrome latch, the remainder bytes being related to syndrome bytes appended to the data block. The generator and remainder recovery circuit includes the Reed-Solomon cross-checking circuit for recovering cross-checking remainder information related to cross check syndrome information in accordance with the polynomial GXC(x)=x.sup.2 +alpha.sup. 134 x+alpha.sup.1.

Cross-checking for on-the-fly Reed Solomon error correction code

A miniature disk drive achieves storage densities of at least approximately 1700 tracks per inch per storage surface of a storage disk defining a series of radially extensive servo sectors embedded within circumferential zones of data tracks. The sectors are recorded at a constant data transfer rate while each zone has a data transfer rate adapted to disk radius. The drive includes a head and head positioner, a read preamplifier for amplifying analog signals read from, and for amplifying signals to be written to, a storage surface. A circuit board carries drive electronics including a read channel, a servo processing circuit for recovering head location information from the servo sectors, a data block sequencer for sequencing data blocks between a buffer and the storage surface, a buffer memory controller for controlling the buffer, a bus level interface circuit for transferring data blocks between the buffer and a host computer, and a programmed digital controller which functions within a head position servo loop and which also controls the sequencer, buffer controller and bus level interface circuit. As one feature, the servo sectors split data blocks into segments. Segment byte counts in each data block header are used by the sequencer automatically to assemble the segments into data blocks during read and to divide the blocks into segments during write. A single VLSI circuit including the sequencer, servo processing circuit, memory controller and an interface to the microcontroller is disclosed.

High capacity submicro-winchester fixed disk drive

An on-the-fly error correction method and apparatus for correcting a data block within a stream of substantially contiguous data blocks during a data decoding process, each block having a Reed-Solomon error syndrome calculated and appended during an encoding process. The method comprises the steps of: passing the block through a syndrome remainder recovery circuit to obtain a remainder related to the error syndrome, comparing the remainder with zero to determine if an error burst is present, and if an error burst is present: latching the remainder into a remainder latch in order to free the syndrome information recovery circuit for the next data block of the stream, causing a multitasked microcontroller to call and execute an error correction service routine and thereupon selectively transferring the remainder from the remainder latch to the microcontroller, determining with the microcontroller the location and a corrected value for the error burst in accordance with a Reed Solomon error correction algorithm, and substituting the corrected value for the error burst within the block detected to contain the error burst before it is delivered to a host system. Cross checking the correction, and error detection of data block ID fields is also disclosed.

On-the-fly error correction with embedded digital controller

A micro-Winchester disk drive subsystem includes a data block sequencer, cache memory and interface for a host computing machine. The drive includes a base and a plurality of non-removable directly rotated disks forming data storage surfaces. A balanced rotary head transducer actuator is mounted to the base for a plurality of data transducer heads among a multiplicity of concentric data tracks formed on each data storage surface of each of the disks. The track following servo system includes a position encoder coupled between the actuator structure and the base, prerecorded data track centerline information at a radially outermost region and at a radially innermost region of each data surface, and a temperature sensor for sensing temperature of the base at the vicinity of the position encoder. An actuator driver circuit is connected to supply electrical driving current to the actuator structure; and, a single, time divided multi-tasked digital including an analog to digital converter is connected to receive the position information from the position encoder, centerline information from the disk surfaces read by the data transducer and temperature sensed by the temperature sensor during a calibration operation in one phase of its operational cycle, the other phase being devoted to supervision data block handling functions of disk drive data block sequencer cache memory and interface. During track following operations, centerline information is derived from information obtained in the calibrate operation. The temperature sensor is periodically checked and recalibration is carried out when drive temperature changes.

Head position control system for fixed drive including position encoder,

A micro-Winchester disk drive subsystem includes a data block sequencer, cache memory and interface for a host computing machine. The drive includes a base and a plurality of non-removable directly rotated disks forming data storage surfaces. A balanced rotary head transducer actuator is mounted to the base for a plurality of data transducer heads among a multiplicity of concentric data tracks formed on each data storage surface of each of the disks. The track following servo system includes a position encoder coupled between the actuator structure and the base, prerecorded data track centerline information at a radially outermost region and at a radially innermost region of each data surface, and a temperature sensor for sensing temperature of the base at the vicinity of the position encoder. An actuator driver circuit is connected to supply electrical driving current to the actuator structure; and, a single, time divided multi-tasked digital including an analog to digital converter is connected to receive the position information from the position encoder, centerline information from the disk surfaces read by the data transducer and temperature sensed by the temperature sensor during a calibration operation in one phase of its operational cycle, and other phase being devoted to supervision data block handling functions of disk drive data block sequencer cache memory and interface. During track following operations, centerline information is derived from information obtained in the calibrate operation. The temperature sensor is periodically checked and recalibration is carried out when drive temperature changes.

High performance, high capacity micro-winchester disk drive

A control system for a micro-Winchester or smaller disk file includes head position control circuitry including at least one servo loop for controlling an electromechanical head positioner relative to a rotating data storage disk, a data controller for controlling reading and writing of data blocks from and to a storage surface of the disk, an interface circuit for connecting the disk file directly to data, address and control buses of a host computer, and a single microprocessor programmed to supervise operations of the head position control circuitry, data controller and interface circuit.

Microprocessor controlled rigid disk file subsystem

An improved control system for a disk file includes head position control circuitry including at least one servo loop for controlling an electromechanical head positioner relative to a rotating data storage disk, a data controller for controlling reading and writing of data blocks from and to a storage surface of the disk, an interface circuit for connecting the disk file directly to data, address and control buses of a host computer, and a single microprocessor programmed to supervise operations of the head position control circuitry, data controller and interface circuit.

An improved rotating disk data storage device is achieved in a combination of an optical encoder to detect data track crossings, a servo sector surface on one of a plurality of rotating data storage disks with the surface being filled with a pattern of alternating bursts which are read for relative amplitude and compared to provide track centerline information. A programmed microprocessor and a rotary actuator for the data transducers combine with the other elements to move the transducers from track to track and keep them on track during data read and write operations.

Rotating rigid disk data storage device

Improvements in a system for controlling the position of a head carriage structure of a rotating disk data storage system are disclosed. The improvements include circuitry for generating a polyphase track boundary signal which compensates for drift, and which doubles or further increases the track density to increase storage capacity. A track centerline sensor circuit is greatly simplified by including the function thereof as microcode routines within a dedicated digital control processor. Error signals are measured periodically across the entire useful field of the disk, and they are constantly updated, so that improved compensation for drift, runout and offset of the disk relative to the data transducer is achieved. Track overshoot during track seeking movements of the transducer is accomodated, enabling reduced track average access time. Self contained diagnostic routines and a direct digital read out provide system status and error messages to operators and maintenance personnel, thereby facilitating maintenance and adjustment.

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San Jose, CA, United States of America

Bruce R Peterson