|
Match
|
Document |
Document Title |
|
|
6989671 |
Detection of slider-disk interference using a dynamic parametric test
A method is described for calculating head disk interference (HDI) using a dynamic parametric test. In one embodiment, HDI is calculated based on an actual and ideal sensitivity profile based on a...
|
|
|
6987628 |
Method and apparatus for high fly write detection using stored amplitude values
A method and apparatus for detecting a high flying condition of a transducer head in a computer disk drive is provided. The method and apparatus allow the detection of high fly write events that...
|
|
|
6980382 |
Magnetic disk drive system
The magnetic disk drive system has a read head and a write head, writes data on the track of the disk, and reads data on the track of the disk. In the present invention, the distance between the...
|
|
|
6975471 |
Data recording medium with servo pattern having pseudo-random binary sequences
A data recording medium, such as a magnetic recording hard disk, has data tracks with pseudo-random binary sequences for the servo information used to control the position of the recording head in...
|
|
|
6975480 |
Method for determining repeatable runout cancellation values in a magnetic disk drive using filtering
A method is disclosed for determining repeatable runout (RRO) cancellation values in a disk drive having a head disk assembly (HDA) and a sampled servo controller. The HDA includes a disk having...
|
|
|
6972540 |
Disk drive employing wedge spindle speed control with eccentricity compensation
A disk drive is disclosed wherein a BEMF speed error is measured during a BEMF spindle speed control mode, and a spindle control current is updated in response to the BEMF speed error to drive the...
|
|
|
6967808 |
Data recording system with servo pattern having pseudo-random binary sequences
A data recording system, such as a magnetic recording hard disk drive, has a recording medium in which the data tracks have pseudo-random binary sequences for the servo information used to control...
|
|
|
6961203 |
Hybrid printed servo patterns for magnetic media and hard disk systems implementing same
A hybrid servo pattern, which is printed onto a disk, for use in a disk drive. The hybrid servo pattern is used to position a head relative to the disk. In one embodiment, the hybrid servo pattern...
|
|
|
6958881 |
Disk drive control system having a servo processing accelerator circuit
Disclosed is a control system for processing sampled servo data in a disk drive. The control system includes a microprocessor and a servo processing accelerator circuit for performing operations on...
|
|
|
6956711 |
Fractional-rate feedforward RRO compensator
An apparatus and method of tracking repeatable runout in a disc drive servo loop is provided in which a feedforward signal having harmonic components that are updated at a sample rate that is a...
|
|
|
6956712 |
Head position demodulating method and disk apparatus
A head position is demodulated by two-phase servo signals of PosN and PosQ from output of the head, so as to acquire a more accurate demodulated position. Saturation of PosN and PosQ is judged from...
|
|
|
6954318 |
Magnetic data embedding apparatus having checking function
Rotary positioners integrally and pivotally stack a read magnetic head for reading a master disk and servo heads for writing to each surface of magnetic disks, the master disk and magnetic disks...
|
|
|
6954325 |
Method and disc drive for writing servo wedges
A method and disc drive are disclosed that write servo wedges to a plurality of tracks of a disc. A head having a read element offset from a write element reads a servo wedge on a first track as a...
|
|
|
6947243 |
Method and system for time-shift based rotational vibration sensing in disk drives
A method (and structure) senses a rotational vibration of a disk drive. The disk drive includes a rotating disk. The disk includes a plurality of reference bits across a surface thereof. The method...
|
|
|
6947233 |
Disk drive apparatus and method for compensating for error in servo-information-recorded position between heads
In a first mode, an R/W channel starts to monitor read information to thereby detect a servo mark contained in servo information, each time a servo controller generates a servo gate pulse. Upon...
|
|
|
6943977 |
Method and apparatus for servo writing in a disk drive
There is disclosed a self-supporting-type servo writing apparatus in which a head of a disk drive is used to write a servo pattern on a disk. In the disk drive, the disk is incorporated in which a...
|
|
|
6943981 |
Methods for improving servo-demodulation robustness
Methods are provided for improving servo-demodulation robustness. SAM pattern detections are characterized as either good SAM detections or bad SAM detections. Further servo functions are then...
|
|
|
6940677 |
Writing distinct servo patterns on individual transducers according to transducer read/write head characteristics in a data storage device
Distinct servo patterns are written on data storage media of a data storage device. Servo patterns of a first type are written for transducers of the data storage device having a first transducer...
|
|
|
6937410 |
Apparatus and method employed in disk drive to enable single signal line to be used for transmission of both read and control signals
A first amplifier which amplifiers a faint read signal read by a head is connected to a second amplifier which further amplifiers the read signal amplified by the first amplifier, via a signal...
|
|
|
6934114 |
Reduced bit number wedge identification techniques within a rotating media storage device
Reduced bit number wedge identification techniques for use within a rotating media storage device (RMSD) are disclosed. The RMSD includes a disk having a circumferential track that includes a...
|
|
|
6930852 |
Method of and apparatus for preventing generating of off-tracking in hard disc drive
A method and apparatus for preventing off tracking from occurring in a hard disc drive that has at least one track formed using servo signals. The method includes preventing off tracking from...
|
|
|
6922304 |
Positioning control device
In a positioning control apparatus, a distance between an actual position at which absolute values of N and Q head positioning signals whose amplitudes vary cyclically in accordance with a position...
|
|
|
6920004 |
Method for adjusting a delay time for opening a servo sector detection window in a disk drive having a spiral track
The present invention may be embodied in a method for adjusting a servo sector detection delay time between detection windows in a disk drive. The disk drive includes a magnetic disk with a spiral...
|
|
|
6917487 |
Seamless and untrimmed primary servo burst with secondary servo bursts
A disk storage system having servo data stored thereon for accurate head position control over a magnetic or other storage medium. The servo data is seamless and untrimmed and consists of a primary...
|
|
|
6914743 |
Vibration cancellation in a disk drive by using an acceleration sensor and adaptively adjusting its gain to minimize external acceleration effects
Disclosed is a disk drive using an accelerometer to sense linear vibration and cancel its effects with an adaptive algorithm during track following. The accelerometer is oriented to detect...
|
|
|
6906485 |
Spindle motor control using a current profile to taper current transitions
Method and apparatus for operating a motor. During a commutation state current is applied to a motor while field effect transistors (FETs) are held in an enable or disable state to effect current...
|
|
|
6882489 |
Dynamic off-track detector
A method and apparatus for dynamically detecting write fault errors is provided. According to the invention, transducer head control parameters are adjusted according to observed events. For...
|
|
|
6882497 |
Track closure error cancellation for a disc drive
Track closure errors written into servo sectors of an information track of a disc of a disc drive are resolved from a position control signal generated by a servo control circuit of a data storage...
|
|
|
6876506 |
Information recording medium, information recording/reproducing head, and information storage device
An information recording medium, an information recording/reproduction head, and an information storage device are provided for performing a track servo operation at a smaller track pitch than that...
|
|
|
6873483 |
Disk drive with servo synchronous recording
A read clock circuit for a disk drive includes a phase-locked loop/voltage controlled oscillator (VFO/PLL) and a frequency synthesizer. The VFO/PLL receives a servo sector transition signal that is...
|
|
|
6865042 |
Embedded servo patterning methods and apparatus
The present invention involves a recordable disk having a first plurality of S 1 servo sample wedges in a first servo zone at an outermost position on the disk, a second plurality of S 2 servo...
|
|
|
6853511 |
Average position error measurement in a data storage device
A number of data pairs, each data pair comprises a write-to-read track misregistration (WRTMR) value and an average position error margin (APE) value, are determined for a data storage device. Each...
|
|
|
6853514 |
Method for measuring PES noise of servo patterned media
A method for measuring servo pattern irregularity and other servo information of pre-patterned servo media mounted on a spindle with the center of the pre-pattern tracks off center from the axis...
|
|
|
6839194 |
Disk drive apparatus and method for generating servo sector pulse
A servo mark detector detects a servo mark from each servo information item detected by the servo detector. A counter measures a time period each time a servo mark is detected, thereby measuring a...
|
|
|
6833972 |
Method for reproducing phase information signals in an information recording device
The data row Pw(i) of phase information obtained by reading preformatted phase patterns on an information recording medium by the head consists of the remainders obtained by dividing the data row...
|
|
|
6813108 |
Servo data detection in presence of radial incoherence using multiple data detectors
Techniques for detecting control data, such as servo data, from input or incoming data read from a magnetic recording medium in the presence of radial incoherence are provided. More specifically,...
|
|
|
6798606 |
Position error signal linearization calibration
Non-linearity in a position error signal (PES) for a data storage device is precisely characterized during a calibration phase in the manufacturing process. From this characterization of the PES...
|
|
|
6798594 |
Position sensing system for a disc drive using micro-servo sectors and side-by-side R/W recording elements
A transducer position sensing system in a disc drive to take frequent data measurements from micro-servo sectors on the disc and to interpret the information to predict recording failures. The disc...
|
|
|
6791778 |
Method and apparatus to detect and manage servo sectors with defect on servo pattern area in hard disk drives
An apparatus, method and computer program product for a hard disk drive defect detection system. In one embodiment, a method of detecting defects on the surface of a disk having a plurality of...
|
|
|
6788489 |
Employing off-track capability in data access operations in a direct access storage device
A direct access storage device (DASD) employs head-specific off-track read capability (OTRC) in data access operations. A method of operation of the DASD involves providing within the DASD a...
|
|
|
6785085 |
Multi-frequency servo bursts in magnetic disc memory system
A servo burst pattern for use in positioning a read/write head with respect to tracks on a magnetic disc medium includes a first set of servo bursts adjacently disposed on the tracks along a first...
|
|
|
6785073 |
Identification and cancellation of cage frequency in a hard disc drive
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...
|
|
|
6785075 |
Self-writing servo and clock fields on a recording medium
A disc drive with an information portion previously written on a rotatable disc surface, a servo write clock generator phase lock loop circuit controlling timing for writing a reference mark to the...
|
|
|
6785084 |
Correction of dynamic track spacing errors in storage devices
The present invention offers a time efficient means to determine and eliminate dynamic track squeeze error. The present invention can be used to correct imperfections in tracks written by a...
|
|
|
6781785 |
Method and system for utilizing circular marks in position error signal patterns
Marks with curved edges are used in data patterns and sensed with proximity recording. Circular, elliptical, and oval marks are examples of marks with curved edges that can be used in the present...
|
|
|
6775081 |
Servo format for disk drive data storage devices
A recording disk contains at least two types of servo sector format, including a first type having a relatively larger track identifying field containing the track number, and a second type having...
|
|
|
6768609 |
Reducing position error signal nonlinearity through iterative calibration of a compensation table
Apparatus and method for reducing nonlinearities in a position error signal (PES) of a disc drive data handling system. The disc drive data handling system includes a disc recording surface having...
|
|
|
6765748 |
Method of interleaving servo information fields for track following and seeking and a recording medium including interleaved servo information fields
A method of interleaving servo information fields on a recording medium, and a corresponding recording medium having interleaved servo information fields, that reduce the amount of disk surface...
|
|
|
6760186 |
Disk drive having first-written servo wedge marked and method for forming marked servo wedges
A disk drive having a marker for identifying the transition between the first and last written servo wedges on a servo track. The marker indicates the likely position where closure error may occur...
|
|
|
6760184 |
Compact servo pattern optimized for M-R heads
A disk drive system has a servo pattern with bursts that are recorded without multiple passes per burst and without trimming, so that the servo pattern bursts have the same width as the data...
|