Agency for Science, Technology and Research

Marvell International Limited

Carnegie Mellon University

Kui Cai

Zhimin Yuan

Anmin Kong

Yibin Ng

Zhiliang Qin

Bo Liu

Vijayakumar Bhagavatula

Li Wang

Siang Huei Leong

Chun Lian Ong

Weiya Xi

Khai Leong Yong

Jianzhong Shi

Quan Jiang

Zhi Yong Ching

Pantelis Sophoclis Alexopoulos

Chao Bi

Kheong Sann Chan

Qide Zhang

Budi Santoso

Jing Zhang

Moulay Rachid Elidrissi

Guchang Han

Chiew Leong Wong

Zhimin He

Jiang Feng Hu

Mengjun Liu

Tiejun Zhou

Yansheng Ma

Ke Gan

Leonard Gonzaga

Wuzhong Lin

Wee Kiat Lim

Sufui Sophia Tan

Cheng Su Soh

Shengkai Yu

Yin Quan Yu

Kannan Sundaravadivelu

Ningyu Liu

Jianqiang Mou

Boon Long Ibrahim See

Venkataramanan Venkatakrishnan

Kees A Schouhamer Immink

Cheng Peng Tan

Chong Wee Lee

Xueqiang Wang

Phyu Hla Nu

Wei Hua

A method of decoding a codeword that satisfies a k constraint into output data includes, using a decoder of a hard disk drive system, converting each bit of the codeword in Non-Return-to-Zero format, extracting, from the converted codeword, a plurality of data blocks comprising a first data block and a plurality of remaining data blocks, performing a first analysis on the plurality of data blocks for modifying each of the plurality of data blocks that satisfies a first predetermined criterion, and performing a second analysis on the plurality of data blocks after the first analysis for modifying each of the plurality of data blocks that satisfies a second predetermined criterion to obtain the output data.

Systems and methods for decoding using run-length limited (RLL) codes

An adaptation technique for decoding low-density parity-check (LDPC) codes for hard disk drive (HDDs) systems is disclosed. The method includes tuning the normalization factor for LDPC decoding for each data zone and read head during the test stage of manufacturing. The LDPC decoder can be either a sum-product algorithm (SPA) decoder or a Min-Sum decoder. The channel detector can be any soft-output detector, such as a soft-output Viterbit detector (SOVA), a BCJR detector, a pattern-dependent noise-predictive (PDNP) detector, or a bi-directional pattern-dependent noise-predictive (BiPDNP) detector. The adaptation technique can optimize the LDPC decoding performance for each data zone and read head, thereby relaxing the acceptance criteria for hard disk drive read/write heads and disk media, enabling acceptance and use of a much broader range of head and media for hard disk drives.

Normalization factor adaptation for LDPC decoding for hard disk drive systems

There is provided an error correction method for a non-volatile memory. The method includes receiving a codeword read from the non-volatile memory, computing a reliability information for each bit of the codeword received, and performing a reduced-complexity soft-decision decoding (SDD) technique to decode the received codeword. In particular, the SDD technique includes forming a set of test patterns based on the reliability data, and determining whether to perform a HDD of a test pattern in the set of test patterns based on a distance between the test pattern and a candidate pattern. There is also provided an error correction module for a non-volatile memory and a memory system incorporating the error correction module.

Error correction method and module for non-volatile memory

A method of encoding an input data into a codeword that satisfy a k constraint includes partitioning the input data into a plurality of data blocks comprising a first data block and a plurality of remaining data blocks; performing a first analysis of the plurality of data blocks for modifying each of the plurality of remaining data blocks that satisfy a first predetermined criterion; performing a second analysis of the plurality of data blocks after the first analysis for modifying each of the plurality of data blocks that satisfy a second predetermined criterion; and converting each bit of the plurality of data blocks after the second analysis to produce the codeword in Non-Return-to-Zero (NRZ) format with the k constraint. There is also provided a method of decoding the codeword with satisfies the k constraint into an output data, and the corresponding encoder and decoder.

Run-length limited (RLL) codes

According to an embodiment of the present invention, a data storage device comprising a motor having a stator is disclosed. The stator may include a substrate having a first surface and a second surface opposite to the first surface; and a n-phase winding arrangement having n phase windings; wherein each phase winding comprises m flat fractional-pitch coils arranged on the first surface of the substrate such that the coils are spaced apart uniformly along a closed loop and connected in series; wherein each coil together with an angular section of the substrate between the coil and an adjacent coil of the same phase winding defines a stator pole-pair; and wherein m is an integer larger than 1.

Data storage device

According to embodiments of the present invention, a memory device with soft decision decoding is provided. The memory device includes a memory cell configured to store an input data bit; a memory sensor configured to read out a parameter associated with a state of the memory cell; a detector configured to determine, based on the parameter read out from the memory cell, a soft information indicating the likelihood that the input data bit stored in the memory cell is a '0' or the likelihood that the input data bit stored in the memory cell is a '1'; and a decoder configured to generate a decoded bit based on the soft information. Further embodiments relate to a method of performing soft-decision decoding on a data bit stored in a memory cell of a memory device.

Memory device with soft-decision decoding

A method performed by a disk drive, comprising: receiving a plurality of signal samples over a channel in the disk drive; executing a forward pattern-dependent noise prediction (PDNP) operation on the plurality of the signal samples; generating, based on execution of the forward PDNP operation, a first detection of recorded data bits in the plurality of received signal samples; executing a backward PDNP operation on the plurality of the received signal samples; generating, based on execution of the backward PDNP operation, a second detection of recorded data bits in the plurality of received signal samples; comparing the first detection to the second detection; identifying, based on comparing, one or more erasures in the received plurality of signal samples; and generating one or more sequences of bits that promote correction of the one or more erasures.

Bi-directional pattern dependent noise prediction

A method and system for encoding a segment of user data words into a segment of code words so that both modulation constraints and a predetermined parity-check constraint are satisfied. Each segment of the user data is partitioned into several data words, and encoded separately by first and second types of component code, which are referred to as the normal constrained code and the parity-related constrained code, respectively. The parity-check constraint over the combined code word is achieved by concatenating the sequence of normal constrained code words with a specific parity-related constrained code word chosen from a candidate code word set. Both the component codes are finite-state constrained codes, which are designed to have rates close to the Shannon capacity. Furthermore, they are based on the same finite state machine (FSM), which enables them to be connected seamlessly, without violating the modulation constraints. Two preferred embodiments are provided to design a code in the non-return-to-zero inverted (NRZI) format and the non-return-to-zero (NRZ) format, respectively. Designing the codes in NRZ format may reduce the number of parity-check bits required for error detection and simplify error correction or post-processing. The parity-check constraint is defined by the parity-check polynomial or parity-check matrix of a systematic linear block code, which could detect any type of dominant error event as well as error event combinations of a given optical recording system. As a result, the information density of the system is improved.

Method and system for encoding and decoding information with modulation constraints and error control

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Singapore, Singapore

Kui Cai