Seagate Technology Incorporated

ChoonKiat Lim

Xiong Liu

Joseph Cheng-Tsu Liu

Qiang Bi

YiRen Hong

James Hart Smith

Kevin Arthur Gomez

Walter Wong

MingZhong Ding

Niroot Jierapipatanakul

Michael Joo Chiang Toh

Pow-Hing Yong

KianKeong Ooi

Myint Ngwe

Wenxiang Xie

Nigel Frank Misso

Beng Wee Quak

Mo Xu

Kian Keong Ooi

UttHeng Kan

Edmun ChianSong Seng

PohLye Lim

Srinivas Tadepalli

YangQuan Chen

Marc Jacques Lalouette

WeiLoon Ng

Joseph C Liu

ShuangQuan Min

Beng Theam Ko

LeeLing Tan

Yongjie Tang

ChorShan Cheng

Wai Onn Chee

Aik Chuan Lim

Andre Y Liem

Shri Hari Narayan

Dave Paul McReynolds

Quock Ying Ng

KayHee Tang

WeiSung Lee

BoonSeng Ong

Todd Warren Kube

Sen Chai Khew

Chiap Heok Ang

Dana P Eddings

Kong Beng Terang Thia

TzeMing Jimmy Pang

Joo Yong Teo

JuiJing Lim

Chenyang Ding

Wen-Jun Cao

HonLeong Wong

Yong Y Yang

A shock absorber is provided that also includes vibration damping. The shock absorber includes at least one shock absorbing frame member that partially surrounds an electronic device enclosure. The shock absorber also includes at least two protrusions that protrude from the at least one shock absorbing frame member. Each protrusion extends beyond the at least one shock absorbing frame member from a recessed surface recessed into the at least one shock absorbing frame member.

Shock absorber capable of damping vibration

An apparatus for unloading a moveable member comprises a ramp structure with an inclined surface. A lift tab of the moveable member advances along the ramp structure to the inclined surface while pivoting about a pivot point to undergo an increase in elevation above a base surface. The inclined surface has a slope determined in relation to angular deflection of the lift tab induced by said increase in elevation. Preferably, the slope of the inclined surface substantially matches an angle of the lift tab when the lift tab is disposed on the inclined surface. The inclined surface preferably constitutes a parking surface, and the ramp structure further preferably comprises an entry/exit ramp surface and a latch surface along which the lift tab travels to reach the parking surface. The moveable member preferably comprises a flexible suspension which supports a transducer adjacent a data storage medium in a data storage device.

Ramp structure with inclined contact surface

A method and apparatus for compensating for errors in servo systems. An improved zero acceleration path (ZAP) correction technique is provided, wherein selected tracks of a data storage device are used for ZAP processing in order to reduce the overall time required to perform error compensation for a storage device. For a given selected track to be ZAPed, track profiles of adjoining tracks are used in addition to the track profile of the selected track as part of the ZAP correction determination for the selected track. Using adjacent track profiles as part of the ZAP correction determination assists in mitigating AC track squeeze issues that would otherwise occur when performing selective track ZAPing.

System and method for reducing ZAP time and track squeeze in a data storage device

A method of preventing a write operation to a disc in a disc drive during a shock event without the use of a separate shock sensor comprises steps of monitoring an actuator voice coil motor (VCM) control plant output signal, generating an actuator voice coil motor (VCM) plant model module output signal, comparing the VCM plant model module output signal to the VCM control plant module output signal to produce a difference signal, and triggering a write protect gate if the difference signal exceeds a predetermined threshold value. The system comprises a voice coil motor (VCM) control plant module sensitive to a shock event providing a VCM control plant module output, a voice coil motor (VCM) plant model module initially insensitive to the shock event producing a VCM plant model module output, a first comparator module coupled to receive the VCM control plant module output and the VCM plant model module output, operable to generate a difference signal between the model plant module output and the VCM control plant module output, and a triggering module receiving the difference signal for generating a write protect gate signal if the difference signal exceeds a predetermined shock threshold.

Soft sensor for operating shock in a disc drive

The present invention is a method of determining mass unbalance of an actuator mechanism in a system. The method includes calculating a center of gravity in first x and y components with respect to a first coordinate system of the actuator mechanism. The method also includes calculating the center of gravity in second x and y components with respect to a second coordinate system of the actuator mechanism. The total mass unbalance of the actuator mechanism is then calculated.

Method of determining the mass unbalance of an actuator

True random numbers are generated from position error signals or like signals. The generator is not dependent on a potentially biased reference or threshold, and is capable of quickly generating true random numbers on demand. The present invention can be implemented as an integral functionality of a data storage device to control access to data stored in the data storage device. It can also be implemented in data storage devices for controlling access to host systems or host devices associated with the data storage devices.

True random number generation

The disc drive housing encloses a spindle motor carrying a disc having a data surface. An actuator assembly includes an actuator arm carrying a head. The housing includes a first surface portion adjacent to the data surface of the disc. The housing also includes a plurality of surface portions that define a recess, which allows the actuator arm to move over the data surface of the disc. The plurality of surface portions include a sloped surface portion sloping away from the data surface and preventing wind generated by the disc rotating about an axis from separating from the sloped surface portion. Alternatively, a disc drive includes a housing that defines a recess. The housing encloses a disc mounted on a spindle motor that rotates the disc about an axis and thereby generates wind within the housing. An upstream surface portion and a downstream surface portion of the housing both face toward a data surface of the disc. A discontinuity, such as a step, between the upstream surface portion and the downstream surface portion causes a wind recirculation region within the recess. The disc drive also includes an actuator arm that carries a head, which the recess allows to move over the data surface of the disc. An actuator limiting device prevents the actuator arm from entering the wind recirculation region.

Disc drive turbulent wind management

Method and apparatus for protecting a data storage device from fluid-borne contaminants. The device includes a housing in which a rotatable disc is supported, the disc having a data recording surface and an outermost perimeter. A filter assembly includes a first filter adjacent to the data recording surface and a second filter disposed beyond the outermost perimeter of the disc. During disc rotation, fluidic currents are generated and impinge a leading edge guide surface of the first filter. A first portion of the currents passes into a gap between the first filter and the data recording surface. A second portion of the currents passes along the leading edge guide surface to the second filter. The first filter is preferably characterized as a chemical adsorbent filter which adsorbs vapor phase (gaseous) contaminants, and the second filter is preferably characterized as a pass-through recirculation filter which captures particulate contaminants.

Fluid-borne contaminant protection using a filter assembly with a leading edge guide surface

A disc drive includes a housing enclosing a spindle motor that is able to spin a disc. A filter within the housing is positioned so that a filter stream of moving gas created by a spinning motion of the disc flows through the filter. Additionally, a flow divider is secured to a portion of the housing and positioned within the filter stream upstream of the filter, splitting the filter stream into a first branch and a second branch. Both branches flow through the filter.

Flow divider upstream of disc drive recirculation filter

The present invention relates to an air guide for use in a disc drive such that air flow can be redirected to improve the efficiency of a filter located within the disc drive. Embodiments of the present invention provide for an air guide having air guide surfaces that, in conjunction with sides of the disc drive housing, are configured to channel air flow off a spinning disc, through a filter, and back into the mainstream air flow. The air guide may be formed as an integral unit with either the inner major surface of the cover or of the baseplate, or both, such that the air guide may extend over part of the disc surface and provide an effective channel for air flow without the need for additional assembly processes during manufacture.

Disc drive housing with air guide

Position error values are obtained from a transducer head while following a plurality of servo tracks with a servo loop that band-blocks a frequency range that includes F, a nominal rotation frequency. An estimated difference distribution is derived from the position error values, the difference distribution having a first frequency component at a positive frequency &#x2266;2*F. A scalar track squeeze magnitude indicator is derived from the estimated difference distribution so that the indicator to be transmitted depends on the frequency component.

Squeeze evaluations that account for low frequency components, in a controller usable in a data handling system

A disc drive having a pivot cartridge and an actuator assembly. The actuator assembly consists of an actuator body which has a bore therein to receive the pivot cartridge. The actuator body further consists of an opening which serves as a ledge to engage a biased retaining ring. The biased retaining ring couples onto the pivot cartridge and forces the pivot cartridge to contact against one side of the bore of the actuator body.

Biased retaining ring for disc drive

An apparatus and method of indirectly measuring half frequency whirl in a spindle motor having a rotor adapted to rotate a disc having a track which is followed by a transducer head that is actuated by a control system is provided. Vibration signals produced at the transducer head while the transducer head follows the track are detected. The half frequency whirl is determined as a function of the detected vibration signals.

Method and apparatus for measuring half frequency whirl in a spindle motor

An apparatus and method of predicting functional capability of a data storage device having a plurality of information tracks, comprising performing a DC erase on three adjacent information tracks, writing a predetermined bit pattern on a middle track of the three adjacent information tracks, providing a first signal from the bit pattern to a variable gain amplifier to generate a first value of the variable gain amplifier, performing DC erases on the information tracks adjacent the middle track, reading the bit pattern from the middle track to provide a second signal to the variable gain amplifier to generate a second value of the variable gain amplifier, and operating on the first and second values of the variable gain amplifier to provide a track mis-registration value for use with a predetermined threshold value to determine the functional capability of the data storage device.

Track mis-registration measurement for a disc drive

A disc drive includes a base and a disc rotatably attached to the base. The disc has an inner diameter and an outer diameter and a plurality of tracks. Information is written on the plurality of tracks. The plurality of tracks are written at a variable track pitch. The tracks positioned near the outer diameter are wider in pitch than the tracks positioned near the inner diameter. The plurality of tracks further include a first group of tracks written at a first track pitch, and a second group of tracks written at a second track pitch. The track pitch of each of the first group and the second group of tracks is selected such that the percentage of track misregistration for each group will be substantially the same. This method provides a means to increase storage capacity for a predetermined track misregistration budget.

Variable track densities on a recording medium to compensate for non-repeatable runout (NRRO) error

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Singapore, Singapore

ChoonKiat Lim