Seagate Technology Incorporated

Kah Liang Gan

Myint Ngwe

Eng Hock Lim

Beng Wee Quak

Quek Leong Choo

Wei Loon Ng

Beng Theam Ko

Pei Koh Lee

James Lai Kein Chang

Nan Ling Goh

Utt Heng Kan

Ban Hok Goh

Fong Kheon Chong

Victor WengKhin Chew

Kong Beng Terang Thia

Hweepeng Teo

Khong Mau Ling

Kwee Teck Say

Sheng Jau Wong

FongKheon Chong

Tze Ming Jimmy Pang

Yu Nang Zai

Kok Hoe Chia

Jun Wang

BengTheam Ko

Bernard Tuang Liang Lim

Chee Wai Lum

Lakshmi Anantha Challa

Lina Wang

LaiKein James Chang

Lian Chong Kwek

Kok Leong Loh

Yam Pheng Tham

A data bus can supply power from a first power source to a sink device. The data bus is coupled to a second power source. An electrical current from the second power source supplements an electrical current on the data bus if the voltage on the data bus decreases to less than a threshold value.

Circuit for supplementing electrical current to a peripheral device

USB storage device housing

A storage device includes a housing having a cavity formed therein which contains a storage unit. A USB cable is electrically connected between a USB plug located outside of the cavity of the housing and the storage unit located in the cavity. A USB cable stress relief mount includes a first USB cable clamp formed in the housing. A second USB cable clamp is formed in the housing and is opposed to the first USB cable clamp. A third USB cable clamp is formed in the housing. The third USB cable clamp is positioned at an angle with the first and second USB cable clamps. The USB cable extends between, and is secured by, the first, second and third USB cable clamps.

USB storage device

A method for optimizing the read-to-write offset of a disk drive system in respect of a track is provided. In one aspect the method includes the step of determining a first read position amongst a range of test positions offset relative to the track on the basis of read signal strength. The method further includes the steps of calculating a subrange of test positions about the first read position, selecting a second read position from the subrange on the basis of bit error rates and setting the read-to-write offset as a function of the second read position. In addition a disk drive system including means for optimally setting the read-to-write offset in respect of a track is provided.

Method and apparatus for determining read-to-write head offset of a disk drive

A guardband portion is written on a disc surface in a disc drive. A predetermined data pattern is written on at least one data track adjacent to the guardband portion. A predetermined guardband pattern is written at a plurality of different guardband frequencies in the guardband portion. For each guardband frequency, at least one performance criterion is measured for the data track. A desired guardband pattern is written on the guardband portion of the disc surface at a guardband frequency chosen based on the measured performance criterion.

Method and apparatus for determining data field fill-in frequency at servo pack writing

A disc drive with on-the-fly verification of an enabled condition of the write element, comprising a rotatable disc having a magnetic recording surface, and a data reading and writing assembly. The data reading and writing assembly comprises a read/write head comprising a write element and a read element, both adjacent the recording surface; a preamplifier comprising a write driver applying a series of write currents for writing data to the recording surface and a read amplifier for reading stored data from the recording surface; and an interconnect joining the write driver to the write element so as to generate time-varying magnetic fields selectively magnetizing the recording surface in response to the write currents, and joining the read amplifier to the read element so as to transduce magnetization vectors on the recording surface associated with stored data. The disc drive furthermore comprises a detection circuit connected to the data reading and writing assembly, receiving a write-safe signal indicative of a write-safe condition, the write-safe signal comprising a sum of constituent operable magnetic coupling values of the read/write head, the preamplifier and the interconnect. The detection circuit is preferably connected to the preamplifier and receives the write-safe signal when a bias current is directed to the read element while writing data to the recording surface, such that a reversal in the writing current generates an electromagnetic coupling effect in the bias current. An advantageous construction comprises adaptively connecting the detection circuit to the analog buffer head voltage terminal of the preamplifier.

Write-safe condition verification apparatus and method for the write element in a disc drive

A method for the adaptive dampening of a peak amplitude of a thermal asperity signal in a disc drive to minimize loss of read data integrity, including the steps of determining a peak-to-peak preamble signal amplitude for identifying an amplitude signal range of the peak amplitude of the thermal asperity signal; measuring the peak amplitude of the thermal asperity signal; separating the peak-to-peak preamble signal amplitude into substantially even portions for use in calculating a value of the amplitude signal range of the peak amplitude of the thermal asperity signal; calculating the value of the amplitude signal range of the peak amplitude of the thermal asperity signal for use in determining a dampening resistance used by a dampening circuit to adaptively dampen the peak amplitude of the thermal asperity signal; and activating the dampening circuit to dampen the peak amplitude of the thermal asperity signal.

Adaptive dampening of thermal asperity events in disc drives

Apparatus and method for transferring data in a disc drive data handling system. A read/write head having separate write and read elements is used to write data to and transduce data from a disc recording surface. A preamplifier driver circuit applies write currents to the write element to write data to the recording surface and to apply a first read bias signal of selected, nonzero magnitude to the read element to transduce data from the recording surface. In response to the assertion of a write gate signal, the preamplifier driver circuit generates a second read bias signal of selected, nonzero magnitude and applies the second read bias signal to the read element while applying the write currents to the write element. This reduces the potential for damage to the read element due to cross-talk noise induced in the read bias signal from magnetic coupling between the read and write elements.

Reducing read element power dissipation levels in a disc drive

A method and apparatus are provided for reading from a storage medium to form data values. A signal is generated from a sector on the storage medium and a section of that signal is identified as having a change in amplitude. A gain multiplier is activated to multiply that section of the signal by a gain value. The gain multiplier is deactivated at the end of the section so that the remaining portion of the sector signal is not multiplied by the gain value. This results in a defect adjusted signal that is applied to a detector to detect data values.

Method and apparatus for data error recovery using defect threshold detector and viterbi gain

A writer coil in a data head of a data storage system is tested by coupling detection circuitry to the writer coil and driving the writer coil with a periodic pulse signal generated by the detection circuitry. As a result, voltage is generated, with the detection circuitry, as a function of an inductance of the writer coil. An inductance of the writer coil is calculated as a function of the generated voltage. Electrical short circuits and discontinuities in the writer coil are identified as a function of the calculated inductance.

Data head writer coil testing

A system for hardware intelligent speed monitoring and auto-retract is disclosed. The system contains a monitoring device that monitors the TACH (Tachometer) output of motor driver. The device provides a trigger to the signal processor and a retract mechanism to retract the actuator when the spindle motor speed is unexpectedly much higher or lower than normal speed. The system DSP (Digital Signal Processor) is unaware of such occurrence.

Intelligent speed monitoring auto retract system

A process of run-time temperature compensating bias current to a magnetoresistive read head in which a plurality of temperature ranges are defined with associated bias current values. A hysteresis range of temperatures is defined for each boundary between temperature ranges. A bias current value is selected based on the temperature range of the sensed temperature. The process is repeated. If the sensed temperature is in a different temperature range from that previously identified and the measured temperature is not in a hysteresis range at the boundary with the temperature range previously identified, the selected bias current value is based on the presently identified temperature range. If the sensed temperature is in a hysteresis range at the boundary with the temperature range previously.

Method and apparatus for run-time temperature compensation of giant magnetoresistive head bias current

A method of manufacturing disc drives. Before a pivot cartridge is assembled into a disc drive, impedance readings of the pivot cartridge are taken, preferably, at more than one rotational position and across a frequency range. The pivot cartridge is accepted for assembly into the disc drive only if its impedance readings compare favorably with readings taken of a good pivot cartridge. Otherwise, the pivot cartridge is rejected and the impedance readings are analyzed to provide identification of the defect in the pivot cartridge. In addition, a system and a storage device readable by a computer system for implementing the method of screening pivot cartridges and identifying causes of defects is provided.

Cartridge screening method with pin-point capabilities on the causes of defects

A method for characterizing a bearing cartridge based on a preload applied to the bearing cartridge used in a disc drive, to increase disc drive yield rates. The method begins by loading the bearing cartridge on to a test fixture and to an actuator assembly such that the actuator is rotatably attached to the base by the bearing cartridge. Then, the method includes inducing a steady swing in the actuator. Then, the method includes measuring a voltage drop that occurs across the bearing cartridge during the steady swing to characterize the preload applied to the bearing cartridge.

Cartridge screening technique by using the electrical dynamic bearing resistance

A method for compensating digital samples of an asymmetric read signal is presented. The method involves reading a digital sample of an asymmetric read signal V(t) ( ), generating a compensated sample at least when the digital sample requires compensation ( ), and outputting either the digital sample ( ) or the compensated sample ( ). Also presented is an asymmetry correction block ( ) of a read channel ( ) of a disc drive ( ) that includes an input ( ), a level detector ( ), a compensator ( ), and an output ( ). The level detector ( ) and the compensator ( ) receive the digital sample through the input ( ). The level detector ( ) determines whether the digital sample requires compensation. The compensator ( ) generates a compensated sample at least when the digital sample requires compensation. The output ( ) selectively outputs either the digital sample or the compensated sample.

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Singapore, Singapore

Kah Liang Gan