Seagate Technology Incorporated

Seagate Technologies, Inc.

Jpmorgan Chase Bank, As Collateral Agent

Myint Ngwe

Beng Wee Quak

Kah Liang Gan

Quek Leong Choo

Eng Hock Lim

Beng Theam Ko

KokHoe Chia

Fong Kheon Chong

Liu Li

Ming Jin

Quan Li

QuekLeong Choo

FongKheon Chong

David Loh

EngHock Lim

Jun Wang

Xiong Liu

Wei Loon Ng

Teck Khoon Lim

Song Wee Teo

CheeWai Lum

Kwee Teck Say

TeckKhoon Lim

Wing Hung Chan

Victor WengKhin Chew

Say Kwee Teck

Khong Mau Ling

Bernard Tuang Liang Lim

KianWai Ng

Chee Wee Cheng

Hwee Peng Teo

Alan Choon Tan

BengTheam Ko

MingYou Hu

Hiau Choon Kee

Hweepeng Teo

Ara Patapoutian

Jian Qiang

Jason Charles Jury

Niroot Jierapipatanakul

ChoonKiat Lim

Choon Wei Ng

BengWee Quak

Joseph C Liu

WeiLoon Ng

Jack Ming Teng

WeiMing Yeow

Sheng Jau Wong

Djohni Chandra

Swee Kieong Choo

James Lai Kein Chang

Zhi Ye

Chiap Heok Ang

JinQuan Shen

SweeKieong Choo

SanYuan Liew

Lan Xia

HiauChoon Kee

Aigang Feng

Andy Chou

CheeWee Cheng

XueYi Miao

Edward Y K Hew

Victor W K Chew

Wong Hon Leong

Zhen Yu Sun

David K L Loh

Lakshmi Anantha Challa

Mathuranathan Viswanathan

Tuang Liang Bernard Lim

Lian Chong Kwek

Kian Wai Ng

KahLiang Gan

Kok Leong Loh

Bernard Tuang Lim

Quak Beng Wee

Zhenyu Sun

Challa Anantha Lakshmi

Kan Liang Gan

HaoJi Bao

Chew WengKhin Victor

Gan Kah Liang

Teng Hou Sebastian Chua

Khai Sheng Ng

Chew Weng Khin Victor

Hong Li Sun

A method and system for providing simultaneous localization of defects in both the time and frequency domain. A high frequency repeating pattern is written on media, and the pattern is read to generate a readback signal, which is converted into ADC samples. The ADC samples are analyzed, in-line, to determine the type of wavelet, level of decomposition, and threshold level for a wavelet transform of the particular readback signal. The wavelet transform provides details and/or approximations (wavelet coefficients) that are analyzed to determine the type, location, and duration of any identified defects. Any noise in the details and/or approximations (wavelet coefficients) is removed by a wavelet based denoising operation. Flags indicating the type, location, and duration of any defects are generated so that the defects may be mapped.

In-line analyzer for wavelet based defect scanning

A data sector is read using two or more passes of a read head over a recording medium. Each of the passes corresponds to a different cross-track offset, each of the data sectors being divided into two or more blocks. For each of the blocks, data is selected from one of the passes that read the block with a higher quality than other passes that read the block. The selected data from each of the blocks to is combined to form recovered data of the data sector.

Combining selected data from two or more passes to recover a data sector

Data is read from a track of a magnetic recording medium via multiple read transducers located at different positions on a read head. The multiple read transducers are substantially positioned over the track when reading the track. The multiple read transducers have different design characteristics manifesting in differences in at least one of magnetic and electrical behavior of the multiple read transducers. One or more signals originating from the multiple read transducers are combined to assist in decoding the data.

Magnetic read head with multiple read transducers each having different design characteristics

Methods including determining a distribution of a position error signal (PES) of a magnetoresistive head by obtaining PES data from a servo controller associated with the magnetoresistive head; determining an encroachment function of a storage disc; and determining a track density of the storage disc by considering both the PES distribution and the encroachment function.

Determining track density capability in a storage device

A method for detecting a contact event between a transducer and a recording medium is disclosed. The method includes positioning a transducer with respect to a recording medium, where the transducer includes a writer, a reader, a heater, and a thermally responsive sensor. The method further includes applying power to the heater to establish a fly height of the transducer; supplying a bias current through the thermally responsive sensor to generate a bias signal; measuring a root mean square (RMS) voltage Vof the thermally responsive sensor based on the bias signal; determining a threshold voltage V; and detecting a contact event between the transducer and the medium based on Vbeing greater than V.

In situ sensor based contact detection

Techniques for data recovery from a data block wherein portions of the data block are written at different off-track positions are described. For example, portions of a data block can be read separately for each on-track and off-track position in the data block; then, the separately read portions can be recombined into a recovered data block.

Partial-block off-track data recovery

The disclosure is related to pulse width modulating a power signal to a heat resistive element of a transducer. The power signal may be a power output signal of preamplifier. The power signal may be provided to a heat resistive element in a transducer that is operable to read data from or write data to a data storage medium. The pulse width modulated power signal can allow for controlling the heating of the heat resistive element based on a thermal time constant of the heat resistive element and based on adjustable components of the pulse width modulated power signal.

Controlling a heat resistive element with a pulse modulated signal

In general, this disclosure describes read recovery techniques for data storage devices that use soft information associated with multiple read operations to detect data. Specifically, the read recovery techniques comprise computing soft information for each bit detected during a first read operation of a data storage medium, computing soft information for each bit detected during a second read operation of the data storage medium and averaging the soft information computed during the first and second read operations to determine the value of each of the bits.

Read error recovery using soft information

Methods and associated apparatus to reduce electrical power consumption in an information channel may include identifying times at which to restore power to elements in the information channel, and restoring power to the elements at the identified times. Times for each element are identified based on a recovery time for that element to reach a sufficiently stable operating point before a transition to an active mode of operation. By maximizing the length of time individual elements may stay in the reduced power mode, power savings may be maximized without negatively affecting information channel performance.

Power management in an information channel

A buffer random access memory has a first portion reserved for a defect table and a second portion reserved for data caching. A method of managing the buffer random access memory includes determining actual memory space of the first portion which is occupied by the defect table. This identifies unused memory space of the first portion of the buffer random access memory. The method then includes reallocating the unused memory space of the first portion of the buffer random access memory for use in data caching. Controllers and mass storage devices which implement the method are also provided.

Method and apparatus for managing buffer random access memory

A method for monitoring a data storage medium is provided in which a virtual head fly profile is measured. In addition, a data storage device for implementing the monitoring method is provided.

Virtual head fly profile measurement

A data word is error correction encoded to provide a worst case codeword without bit transitions between worst case codeword bits. A modulation bit is calculated as a function of the worst case codeword. The modulation bit has a bit polarity opposite a bit polarity of the worst case codeword bits. The worst case codeword bits are added with the modulation bit to form a modulated code word.

Modulation bit added to worst case codeword

A system and method for performing read retry operations with respect to an erroneously read data sector is disclosed. The system and method use estimates of bit error rates determined during previous attempts to read data from the sector to determine an optimal distance and direction to move a read transducer for a subsequent read retry of the erroneously data sector.

System and method for performing adaptive read retry operations in a data storage device

A motion control system has an enclosed assembly that encloses moving parts. A controller controls a motion of the moving parts and has an inhibit input that inhibits the motion. A sensor provides sensor outputs that depend on an assembly temperature and an assembly humidity in the enclosed assembly. A circuit provides a condensing condition output as a function of the sensor outputs. The condensing condition output couples to the inhibit input to inhibit the motion as a function of the sensor outputs.

Condensation compensation in a motion control system

According to one embodiment of the present invention, a method of tuning a Power-On-Reset (POR) register in a data storage device comprises determining a tuned value for the POR register using feedback from the data storage device obtained during a certification process of the data storage device and storing a list in one or more system sectors of the data storage device, the list comprising an address of the POR register to be patched and the tuned value. According to another embodiment of the present invention, a disc drive comprises a rotatable disc, a microprocessor, and a memory. The memory has a start-up routine that, when executed by the microprocessor, causes the microprocessor to patch a Power-On-Reset (POR) register using a tuned values stored in one or more system sectors of the rotatable disc.

Dynamic mask-ROM register patching

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Singapore, Singapore

Myint Ngwe