Seagate Technology Incorporated

BengWee Quak

KianKeong Ooi

MingZhong Ding

WingKong Chiang

Xiong Liu

Qiang Bi

UttHeng Kan

Edmun ChianSong Seng

YangQuan Chen

ShuangQuan Min

KokHoe Chia

Kwee Teck Say

Jimmy Pang

KianSoon Yeo

WeiMing Yeow

WeiSung Lee

TaiVie Chiang

Ricardo SoonLian Lim

Myint Ngwe

Tien Hiong Lee

Teck Khoon Lim

WeiLoon Ng

Ricky Wei Watt Yeo

Wesley Chan

CheeWai Lum

Patrick TaiHeng Wong

LeeLing Tan

Wing Kong Chiang

TeckKhoon Lim

Jianyi Wang

JiaHong Shu

JackMing Teng

SweeKieong Choo

ChoonHoe Koh

HengChang Guo

WaiKhay Chan

YuNang Zai

Djunaedy Chandra Ang

Kong Yaw Lucas Lee

Ricky WeiWatt Yeo

ChiapHeok Ang

EikFun Khor

KianKeon Ooi

Patrick TaiHeng

BaoHong Liu

MingZhong Dong

A storage medium format is provided having a first band of a plurality of consecutive data storage tracks having user data stored thereto, a second band of a plurality of consecutive data storage tracks having other user data stored thereto, and a guard track medially disposed therebetween the first band and the second band and having system data stored thereto.

Data storage medium having system data stored in a guard band between zones of consecutive data storage tracks

A data storage medium and data storage system with improved efficiency of formatting are provided. One illustrative embodiment of the present invention pertains to a data storage medium. The data storage medium includes a first zone having servo information written with a first frequency, a second zone having servo information written with a second frequency, and a guard band disposed between the first zone and the second zone. The use of different frequencies in different zones contributes to optimizing the properties of the data storage medium, and the guard band contributes to optimizing the usage of the different zones.

Data storage medium with optimized servo format

A motion pattern of an actuator supporting a head is monitored during/after a disc spin-up. The monitor's signal is configured to generate a digital indication of where the head was just before the spin-up. The digital indication is optionally a single-bit indicator that is used directly as a decision of whether to continue a start-up operation.

Sensing a prior transducer position by a motion pattern

A location within a cycle is determined by reading a portion of a cyclic bit sequence, the bit sequence containing several interspersed bit-group sets that each contain a plurality of series that each consist of several consecutively-placed identical bit-groups. On a data surface in a disc drive, each bit group can be stored and accessed in unused bits of each servo sector's digital portion.

Determining a location based on a cyclic bit sequence containing consecutively-placed identical bit-groups

Methods relating to compensating a pre-defined seek profile for use in a data storage device, such as a disc drive, to manage the internal temperature of the device are disclosed. One embodiment disclosed is related to determining a seek profile compensation value that can be used to compensate the pre-defined seek profile for temperature. Another embodiment is a method of using a seek profile compensation value during device operation to maintain the data storage device operating temperature below an operating temperature threshold. Yet another embodiment of the present invention may be thought of as a controller for a data storage device. The controller comprises a microprocessor having a pre-determined seek profile and a means for compensating the pre-determined seek profile based on a current operating temperature.

Temperature compensation of seek profiles in data storage devices

Method and apparatus for increasing process yields of data storage devices which store data on media surfaces using read/write heads. An initial linear bit recording density is determined for each head, the linear bit recording density comprising a density at which each head is capable of writing data to and reading data from the corresponding media surface. Defective storage sectors are identified on the media surfaces to determine whether a sufficient number of logical storage sectors are available to meet a predetermined data storage capacity. The linear bit recording density of at least one of the heads is then altered to ensure that the storage device has sufficient logical storage sectors to meet the predetermined capacity.

Method and apparatus for increasing process yields of data storage devices

Written-in runout due to vibration of the cage of a spindle motor of a disc drive is detected by identifying an initial cage frequency value of the motor. A written-in magnitude of successive servo burst closures, D(n ), is read over a plurality of tracks, and a maximum servo burst closure D(n ) is identified from the plurality of read servo bursts. A magnitude of the cage frequency at a servo sector n is calculated based on a difference between the read magnitudes of the servo burst closures at servo sectors n and n , and a phase of the cage frequency is calculated based on the magnitude of the written-in cage frequency at servo sector n . The profile, in the form of cage frequency, maximum servo burst closure magnitude, and initial phase, is stored in a memory or table for each of a plurality of radial zones of tracks. The profile is combined with a position error signal and applied to the controller in a feed forward scheme to adjust the position of the head based on the written-in runout.

Identification and cancellation of cage frequency in a hard disc drive

An apparatus and method for writing a product information code (PIC) to a head-disc assembly (HDA) of a disc drive data handling system to facilitate subsequent identification of the HDA. The PIC is configured as a sequence of n multi-bit encoded words. Servo data are written to a disc of the HDA as a number of p angularly spaced apart servo data fields, the servo data used by a servo control circuit to effect head positional control. The n encoded words are distributed across a subset n of the p servo data fields so that the n encoded words replace at least a portion of the servo data in the n servo data fields. Preferably, the n encoded words are written to Gray code (track address) fields of the n servo data fields and are provided with error detection and correction capabilities.

Head-disc assembly with embedded product identification code

A method and apparatus for reducing retry redundancy during disc read operations in a disc drive system are provided in which a number of physical sectors to be read from the disc during read operations is first determined. An attempt is then made to read all sectors of the number of sectors during a first disc revolution. Failed sectors of the number of sectors during the first disc revolution are also identified. A retry cycle is then performed on the failed sectors during a second disc revolution following the completion of the attempt to read all sectors of the number of sectors during the first revolution.

Method and apparatus to reduce retry redundancy during read operations

A method of handling multiple resonance frequencies in a disc drive includes monitoring a position error signal (PES) for an actuator arm, generating a plurality of feedforward compensation signals from the PES using a plurality of bandpass filters, and applying the compensation signals to a servo control signal. Each filter has a center frequency that is set to a problematic resonance frequency. The method may also include identifying the problematic frequencies by, for example, commanding a movement of the actuator arm, collecting data points for the PES that are associated with the movement, and performing a digital fourier transform of the data points to identify resonant frequencies. Other methods of identifying problematic frequencies include analyzing PES zero-crossing data, or using principal component analysis.

Method and apparatus for handling multiple resonance frequencies in disc drives using active damping

A method sets bit densities and track densities for a plurality of heads in a data storage device. The method includes determining an initial bit density and an initial track density for each head. An initial total capacity for the storage device is determined based on the initial track densities and the initial bit densities. A desired capacity for the storage device is selected and the initial total capacity and the desired capacity are compared. One of either a bit density or a track density is then adjusted so that the data storage device has an adjusted capacity that provides some excess capacity over the desired capacity where the excess capacity is less than any excess capacity that was present between the initial capacity and the desired capacity. A data storage device formed through this method is also provided.

Adjusting track density and bit density to provide limited excess capacity in a storage device

The magnitude and frequency of runout due to vibration of the cage of the spindle motor is detected. A plurality of servo patterns are written to a reference track having a clock pattern on the disc, and the plurality of servo patterns are then read over a plurality of revolutions of the disc using a clock head. The magnitude of position error of the clock head relative to the reference track is identified for each of the read servo patterns. The magnitude and frequency of runout due to cage vibration is identified from the position errors. Servo patterns are written to user tracks on the disc by identifying periods of low magnitude runout due to cage vibration, and writing the servo patterns to the user track during those periods of low magnitude runout.

Detection and cancellation of cage frequency using the clock head in a servowriter

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BengWee Quak