Seagate Technology Incorporated

David Christopher Pruett

Wilson Massey Fish

Mark A Gaertner

Mark Alan Heath

Travis Eugene Ell

Apparatus and method for positioning a head adjacent tracks on a recording surface in a disc drive. A servo control circuit includes a multi-mode servo position error signal (PES) demodulator circuit having an operand generator which outputs operand values from decoded servo position data transduced by the head from the disc surface, and a PES generator which generates a PES indicative of head position with respect to the disc surface in accordance with a selected PES mode from a population of mutually exclusive PES modes each derived from a different combination of selected operand values. A programmable servo processor outputs a current adjustment signal to adjust the current applied to an actuator motor in relation to the PES and a desired position. The servo processor selectably configures the PES generator for each track so that different PES modes are used for different tracks.

Multi-mode servo position error signal demodulator circuit

A method for improving the operational performance of a disc drive through the identification of vital product information associated with a head-disc assembly (HDA) of the disc drive. The disc drive comprises a printed wiring assembly (PWA) housing control circuitry for the disc drive. The HDA of the disc drive is operably coupled to the printed wiring assembly and includes a rotatable disc to which data are written by a controllably positionable head. A non-volatile memory device is mounted on the HDA and operably coupled to the PWA so that, when the disc drive is initialized, the PWA verifies the configuration of the HDA before proceeding with the initialization of the disc drive, thereby preventing errors and damage to the disc drive as a result of the installation of a new, replacement PWA in the disc drive, or the downloading of new, incorrect firmware to the PWA.

Detecting a mismatch between a head disc assembly and a printed wiring assembly in a disc drive

Apparatus and method which provide accelerated servo control value calculations for a control processor controlling an actuator maintaining a head adjacent a rotatable disc f a disc drive. A dedicated multiply-accumulate hardware core of a servo micro engine calculates sum-of-products terms common in servo control loops. The multiply-accumulate hardware core uses a pipeline with stages for fetch, read, multiply, accumulate, and write-back as an arithmetic core to fully utilize all of the hardware during every servo interval. Feeding this arithmetic core is a dedicated state memory, from which a first signed servo state and a second signed servo state are read and where calculation results may be optionally written. Another, independent, coefficient memory provides predetermined coefficients used in resolving servo control loop algorithms. A final dedicated instruction memory provides shifter control values and the addresses of the states and coefficients.

Accelerated servo control calculations method and apparatus for a disc drive

A data storage system and method of scheduling commands in such a data storage system are provided in which commands are stored in a command sort queue and a scheduled command queue. Commands in the command sort queue are sorted and assigned a priority. Eventually, commands in the command sort queue are transferred to the scheduled command queue. Commands in the scheduled command queue are executed without further sorting. The desired queue depth or size of the scheduled command queue is determined as a function of both the queue depth of the command sort queue and a command execution rate value which is indicative of the rate at which commands in the scheduled command queue are executed. The desired queue depth may be dynamically determined using the queue depth of the command sort queue and the command execution rate value as inputs to a look-up table. The data storage system may include a small computer system interface (SCSI) disc (or &ldquo;disk&rdquo;) drive which executes commands from a host system.

Disc drive data storage system and method for dynamically scheduling queued commands

An apparatus for improving the operational performance of a disc drive through the identification of vital product information associated with a head-disc assembly (HDA) of the disc drive. The disc drive comprises a printed wiring assembly (PWA) housing control circuitry for the disc drive. The HDA of the disc drive is operably coupled to the printed wiring assembly and includes a rotatable disc to which data are written by a controllably positionable head. A non-volatile memory device is mounted on the HDA and operably coupled to the PWA so that, when the disc drive is initialized, the PWA verifies the configuration of the HDA before proceeding with the initialization of the disc drive, thereby preventing errors and damage to the disc drive as a result of the installation of a new, replacement PWA in the disc drive, or the downloading of new, incorrect firmware to the PWA.

Growing community of inventors

Oklahoma City, OK, United States of America

David Christopher Pruett