Dphi Acquisitions, Inc.

Seagate Technology Incorporated

Oracle International Corporation

Maxtor Corporation

Optical Devices, LLC

Dphi Acquistions, Inc.

Charles R Watt

Ron Kadlec

Christopher J Turner

Hans Brandon Wach

John W Vanlaanen

Bruce A Liikanen

Lin Guo

Don Brunnett

Faramarz Mahnad

Yu Sun

Scott David Wilson

Stan Shepherd

Fred R Hansen

S Craig Smith

Dave McMurtrey

Steven J Alfred

Todd Franks

Steve Ray

Xiao Zhang

Methods and systems are described for correcting repeatable runout. In one aspect, an open loop tracking signal is received and squared. A discrete Fourier transform (DFT) of the squared open loop tracking signal is obtained. A velocity magnitude and an absolute value of the phase of the open loop tracking signal is determined. A RRO correction signal is iteratively constructed by performing a partial correction based on an initial phase selected and an initial velocity amplitude, measuring a relative velocity amplitude, performing a partial control correction using the initial phase and relative velocity amplitude if the amplitude is smaller than an initial amplitude or using the initial phase rotated by one hundred eighty degrees and the relative velocity amplitude if the amplitude is larger than an initial amplitude, and repeating the above steps until a tracking controller can perform closed loop control of the track to optical pickup unit velocity.

Methods, systems, and computer program products for correcting repeatable runout

Various embodiments herein include utilities that facilitate the substantially flat and aligned mounting of optical tape segments on testing drums to increase testing accuracy of the tape segments. In this regard, a drum for testing optical tape media is disclosed having a substantially planar portion onto which first and second ends of an optical tape segment may be mounted to thereby secure the entire tape segment around an outer testing surface of the drum. Also disclosed is fixture that may be used to precisely mount and secure the tape segment over the outer mounting surface of a drum in a manner that reduces axial run-out and wrinkling of the optical tape.

Drum for use in testing optical tape media and method and apparatus for mounting optical tape media on drum

Methods for writing servo fields on a rotatable data storage disk using reference patterns on the data storage disk include generating a clock signal, reading a reference pattern signal from a surface of the disk, generating a phase error signal in response to a phase offset between the clock signal and the reference pattern signal, subtracting a timing control value from the phase error to provide an adjusted phase error, generating a frequency control signal in response to the adjusted phase error, and adjusting the frequency of the clock signal. The timing control value is generated in response to the phase error signal and the frequency control signal.

Self-servo writing using reference patterns with timing correction

A multi-zone calibration system is disclosed. The multi-zone calibration system calibrates the operating parameters of an optical disk drive over a plurality of zones over an optical media. The optical media, in addition, can have writeable and premastered portions. The operating parameters can be calibrated for each of the media types in each of the zones. Additionally, the operating parameters can be calibrated for each type of operation (e.g., read or write) in each zone.

Digital focus and tracking servo system with multi-zone calibration

A servo system with in an optical disk drive with an inverse non-linearity compensation is disclosed. An error signal calculated from signals received from an optical pick-up unit can be offset by an offset value and amplified by a gain in the early stages of a calculation of a control signal for controlling a position of the optical pick-up unit. The non-linearity compensation adjusts the gain based on the offset value so that the response of the servo system to changes in the error signal is substantially linear. The error signal can be the tracking error signal in a tracking servo system and can be the focus error signal in a focus servo system.

Digital servo system with inverse non-linearity compensation

Methods according to some embodiments include writing servo patterns on a data storage medium including a plurality of timing patterns in response to phase correction values generated using a phase correction value (PCV) kernel having a length that is less than the number of timing patterns on the data storage medium.

Reduced convolution for repetitive disturbance rejection

A focus servo system with a focus close algorithm is disclosed. The focus close algorithm provides a bias control effort to the focus servo system when focus is closed. A method of closing focus includes positioning an optical pick-up unit at a first position away from an optical medium, moving the optical pick-up unit towards a second position by altering a focus control effort, monitoring a sum signal obtained from signals received from the optical pick-up unit, and setting the bias control effort to the focus control effort when a closure criteria is satisfied. In some embodiments, the closure criteria includes that a sum signal exceeds a threshold value. In some embodiments, the closure criteria includes that a focus error signal is below a FES threshold.

Close focus algorithm in a digital focus servo system

A rate of occurrence of off-track write events is determined. A seek function control parameter for a head is adaptively adjusted based on the determined rate of occurrence of the off-track write events. Related circuits and devices are also discussed.

Adaptively adjusting seek function control parameters based on off-track write events

In accordance with various embodiments, a rotatable member is mounted to a spindle hub so that initial servo data previously provided to the rotatable member are eccentrically offset with respect to a rotational center of the spindle hub. Compensation vales are determined to characterize said offset, after which final servo data are provided to the rotatable member in relation to the initial servo data and the determined compensation values. The final servo data are nominally concentric with the rotational center of the spindle hub.

Servo writing with offset compensation for prewritten reference

A tracking and servo system with a one-track jump is disclosed. The one track jump algorithm holds a control signal from the tracking servo system. The one track jump algorithm adds an acceleration control signal to the held control signal for a first period of time, delays for a second period of time, and adds a deceleration control signal to the held control signal for a third period of time. The algorithm then frees the control signal to close tracking on a new track separated by one track from the starting track.

Digital focus and tracking servo system with one-track jump

A method of storing calibrated optical parameters is presented. In some embodiments, calibrated optical parameters are stored in place of stored parameters. In some embodiments, averages between the calibrated operating parameters and stored optical parameters are stored. In other embodiments, the stored optical parameters are allowed to vary only by a maximum amount. In some embodiments, if the calibrated parameters vary by more than threshold values, then the calibrated parameters are not stored.

Calibration storage methods for a digital focus and tracking servo system with calibration

A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The present invention includes starting the operation of a motor including windings and a rotor; placing the motor in a first operational state; driving the motor from the first operational state to a second operational state; and sensing a variation in an electrical waveform induced by driving of the motor to determine a cycle period from which the speed of the motor can be determined.

System and method for performing a spin motor startup operation

A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to read a physical sector address (PSA) from an optical medium, calculate a table index based on the PSA, enter a lookup table module to acquire reference data, and maintain a constant data rate transfer from the optical medium for a range of PSAs.

CLV system and method using PSA lookup

A control system for controlling tracking and seeking in an optical disc drive for optical media with a pitted premastered area that cannot be overwritten and a grooved user-writeable area that can be overwritten. The control system determines whether an optical pickup unit is over the premastered or the writeable areas of the optical media by measuring peak to peak amplitude of a tracking error signal. Gains and calibration values are selected based on whether an optical pickup unit is over the premastered or the writeable areas of the optical media. Reading from and writing to the optical media is disabled while jumping tracks. Control of jumping tracks on the optical media includes controlling: jumping a single track on the optical media; jumping a specified number of tracks every specified number of revolutions of the optical media; auto jumpbacks, and jumping in forward or reverse directions. Parameters for controlling jumps include at least one of: jump type, number of tracks to jump, time delay between track jumps, number of revolutions of the optical media between jumps, and whether it is not safe to read from or write to the optical media. The control system performs long seeks by predicting whether the tracking actuator arm will be positioned over the premastered area or the writeable area at the end of the long seek, and to load calibration parameters corresponding to the type of media over which the tracking actuator arm will be positioned at the end of the long seek.

System and method for controlling tracking and seeking in an optical disc drive

A system for controlling focus in an optical disc drive for optical media with a premastered area that cannot be overwritten and a user-writeable area that can be overwritten includes instructions for turning focus on and off; and for acquiring focus on the optical media in response to a command to acquire focus. The actuator arm is moved according to a sinusoidal ramp function to prevent exciting resonances in the actuator arm. The amount of push-away force used while moving the actuator arm can be adjusted to avoid overshoot. The integrity of a focus error signal is determined and an attempt to re-acquire focus is made if the focus error signal indicates a bad focus status. The system turns focus off when at least one of the following conditions are met: (1) current state is a ramp focus acquire state and the maximum ramp position was reached; (2) current state is a focus push retry state and best push away value is greater than or equal to a predetermined fraction of a nominal push away value; or (3) a focus problem develops while in a focus active state.

Growing community of inventors

Longmont, CO, United States of America

Charles R Watt