Patents by Inventor Richard L. Galbraith

Richard L. Galbraith has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20220398153
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). Problematic patterns in a block of input data are identified, and the problematic patterns are relocated from an initial location to an erasure region of the block to generate a modified block. The modified block is erasure encoded into an erasure codeword, at least part of the erasure codeword is stored in the NVSM.
    Type: Application
    Filed: June 11, 2021
    Publication date: December 15, 2022
    Inventors: IOURI OBOUKHOV, RICHARD L. GALBRAITH, JONAS A. GOODE
  • Patent number: 11513895
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). Problematic patterns in a block of input data are identified, and the problematic patterns are relocated from an initial location to an erasure region of the block to generate a modified block. The modified block is erasure encoded into an erasure codeword, at least part of the erasure codeword is stored in the NVSM.
    Type: Grant
    Filed: June 11, 2021
    Date of Patent: November 29, 2022
    Assignee: Western Digital Technologies, Inc.
    Inventors: Iouri Oboukhov, Richard L. Galbraith, Jonas A. Goode
  • Patent number: 11411584
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). A first block of data is channel encoded into first channel data based on a channel code constraint, and the first channel data is error correction encoded to generate first redundancy bits. A second block of data is channel encoded into second channel data based on the channel code constraint and the first redundancy bits, and the first channel data and the second channel data are error correction encode to generate second redundancy bits. A third block of data is channel encoded into third channel data based on the channel code constraint and the second redundancy bits. The first, second and third channel data and the first and second redundancy bits are stored in the NVSM.
    Type: Grant
    Filed: February 19, 2021
    Date of Patent: August 9, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Iouri Oboukhov, Richard L. Galbraith, Niranjay Ravindran
  • Patent number: 11386927
    Abstract: A data storage device configured to access a magnetic tape is disclosed comprising a plurality of data tracks. A first head is configured to access a first data track comprising a first sync mark, and a second head is configured to access a second data track comprising a second sync mark. The first head is used to read first data from the first data track, wherein the first data comprises a plurality of symbols, and the second head is used to read the second sync mark from the second data track. The first data is symbol synchronized based on the second head reading the second sync mark from the second data track.
    Type: Grant
    Filed: May 26, 2021
    Date of Patent: July 12, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Derrick E. Burton, Weldon M. Hanson, Richard L. Galbraith, Iouri Oboukhov
  • Patent number: 11295764
    Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a write element and a first read element. A preamp circuit comprising an interface includes at least a write line associated with the write element of the head and a first read line associated with the first read element of the head. A first read signal is received from the preamp circuit over the first read line during a read operation, and configuration data is transmitted to the preamp circuit over the first read line during a write operation.
    Type: Grant
    Filed: March 28, 2021
    Date of Patent: April 5, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Jonas A. Goode, Richard L. Galbraith, Joey M. Poss, John T. Contreras
  • Publication number: 20220103188
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). A first block of data is channel encoded into first channel data based on a channel code constraint, and the first channel data is error correction encoded to generate first redundancy bits. A second block of data is channel encoded into second channel data based on the channel code constraint and the first redundancy bits, and the first channel data and the second channel data are error correction encode to generate second redundancy bits. A third block of data is channel encoded into third channel data based on the channel code constraint and the second redundancy bits. The first, second and third channel data and the first and second redundancy bits are stored in the NVSM.
    Type: Application
    Filed: February 19, 2021
    Publication date: March 31, 2022
    Inventors: IOURI OBOUKHOV, RICHARD L. GALBRAITH, NIRANJAY RAVINDRAN
  • Patent number: 11289123
    Abstract: An external servo writer configured to write a plurality of embedded servo sectors on a magnetic tape to define a plurality of data tracks is disclosed. A first part of the plurality of embedded servo sectors is written while controlling an actuator to first move a head vertically along a width of the magnetic tape. A second part of the plurality of embedded servo sectors is written while controlling the actuator to second move the head vertically along the width of the magnetic tape.
    Type: Grant
    Filed: June 17, 2021
    Date of Patent: March 29, 2022
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Derrick E. Burton, Niranjay Ravindran, Iouri Oboukhov
  • Publication number: 20210350825
    Abstract: An external servo writer configured to write a plurality of embedded servo sectors on a magnetic tape to define a plurality of data tracks is disclosed. A first part of the plurality of embedded servo sectors is written while controlling an actuator to first move a head vertically along a width of the magnetic tape. A second part of the plurality of embedded servo sectors is written while controlling the actuator to second move the head vertically along the width of the magnetic tape.
    Type: Application
    Filed: June 17, 2021
    Publication date: November 11, 2021
    Inventors: RICHARD L. GALBRAITH, WELDON M. HANSON, DERRICK E. BURTON, NIRANJAY RAVINDRAN, IOURI OBOUKHOV
  • Patent number: 11138996
    Abstract: A data storage device is disclosed comprising at least one head configured to access a magnetic tape comprising a plurality of data tracks, wherein each data track comprises a plurality of data segments and a plurality of servo sectors. The head is used to read one of the servo sectors to generate a first read signal. The first read signal is processed to generate a position error signal (PES) of the head relative to the magnetic tape, wherein the head is positioned relative to the magnetic tape based on the PES. The head is used to read one of the data segments to generate a second read signal, wherein the second read signal is processed to detect user data recorded in the data segment.
    Type: Grant
    Filed: May 8, 2020
    Date of Patent: October 5, 2021
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Derrick E. Burton, Niranjay Ravindran, Iouri Oboukhov
  • Patent number: 11055171
    Abstract: A data storage device is disclosed comprising a head actuated over a disk. A first plurality of codewords and corresponding parity sector are generated, and a second plurality of codewords and corresponding parity sector are generated. The first and second plurality of codewords are written to the disk, and during a read of the first and second set of codewords, M codeword locations within the data track that are unrecoverable are saved, and N codeword locations out of the M codeword locations are selected based on a quality metric of the read. The N codewords are reread from the data track at the N codeword locations and reliability metrics associated with the N codewords are saved. The saved reliability metrics are updated using at least one of the first parity sector or the second parity sector.
    Type: Grant
    Filed: March 11, 2020
    Date of Patent: July 6, 2021
    Assignee: Western Digital Technologies, Inc.
    Inventors: Niranjay Ravindran, Weldon M. Hanson, Richard L. Galbraith, David T. Flynn, Iouri Oboukhov
  • Patent number: 11049520
    Abstract: A data storage device is disclosed comprising at least one head configured to access a magnetic tape. Data is read from the magnetic tape to generate a read signal which is processed to decode a first M blocks of low density parity check (LDPC) type codewords using a LDPC type decoder. First un-converged codewords out of the first M blocks are decoded using a first M-blocks parity, and second un-converged codewords out of the first M blocks are decoded using an erasure code.
    Type: Grant
    Filed: May 8, 2020
    Date of Patent: June 29, 2021
    Assignee: Western Digital Technologies, Inc.
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Derrick E. Burton, Niranjay Ravindran, Iouri Oboukhov
  • Publication number: 20200210277
    Abstract: A data storage device is disclosed comprising a head actuated over a disk. A first plurality of codewords and corresponding parity sector are generated, and a second plurality of codewords and corresponding parity sector are generated. The first and second plurality of codewords are written to the disk, and during a read of the first and second set of codewords, M codeword locations within the data track that are unrecoverable are saved, and N codeword locations out of the M codeword locations are selected based on a quality metric of the read. The N codewords are reread from the data track at the N codeword locations and reliability metrics associated with the N codewords are saved. The saved reliability metrics are updated using at least one of the first parity sector or the second parity sector.
    Type: Application
    Filed: March 11, 2020
    Publication date: July 2, 2020
    Inventors: NIRANJAY RAVINDRAN, WELDON M. HANSON, RICHARD L. GALBRAITH, DAVID T. FLYNN, IOURI OBOUKHOV
  • Patent number: 10592334
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM), wherein a plurality of codewords and corresponding parity sector are written to the NVSM and then read from the NVSM. Each codeword read from the NVSM is processed using a Viterbi-type detector, thereby generating codeword reliability metrics. The codeword reliability metrics for at least some of the codewords are processed using a low density parity check (LDPC) type decoder, thereby generating a LDPC reliability metric for each symbol of at least one codeword. The LDPC reliability metrics for at least one of an un-converged codeword are processed using the parity sector, thereby updating the un-converged codeword reliability metrics. Processing the codeword reliability metrics with the LDPC decoder and updating the reliability metrics with the parity sector is repeated at least once before updating the LDPC reliability metrics of at least the un-converged codeword using the Viterbi-type detector.
    Type: Grant
    Filed: May 17, 2018
    Date of Patent: March 17, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Iouri Oboukhov, Niranjay Ravindran, Richard L. Galbraith
  • Patent number: 10530390
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a data track having at least a first data segment and a second data segment. A first plurality of codewords are generated, and a first parity sector is generated over the first plurality of codewords. The first plurality of codewords and the first parity sector are written to the first data segment. A second plurality of codewords are generated, and a second parity sector is generated over the second plurality of codewords. The second plurality of codewords and the second parity sector are written to the second data segment. During a read operation the data segments of the data track are processed sequentially to decode the codewords using a low density parity check (LDPC) decoder, wherein the reliability metrics of un-converged codewords are stored in a codeword buffer and updated using the respective parity sector.
    Type: Grant
    Filed: May 17, 2018
    Date of Patent: January 7, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Iouri Oboukhov, Weldon M. Hanson, Niranjay Ravindran, Richard L. Galbraith
  • Publication number: 20190354430
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM), wherein a plurality of codewords and corresponding parity sector are written to the NVSM and then read from the NVSM. Each codeword read from the NVSM is processed using a Viterbi-type detector, thereby generating codeword reliability metrics. The codeword reliability metrics for at least some of the codewords are processed using a low density parity check (LDPC) type decoder, thereby generating a LDPC reliability metric for each symbol of at least one codeword. The LDPC reliability metrics for at least one of an un-converged codeword are processed using the parity sector, thereby updating the un-converged codeword reliability metrics. Processing the codeword reliability metrics with the LDPC decoder and updating the reliability metrics with the parity sector is repeated at least once before updating the LDPC reliability metrics of at least the un-converged codeword using the Viterbi-type detector.
    Type: Application
    Filed: May 17, 2018
    Publication date: November 21, 2019
    Inventors: IOURI OBOUKHOV, NIRANJAY RAVINDRAN, RICHARD L. GALBRAITH
  • Publication number: 20190356334
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a data track having at least a first data segment and a second data segment. A first plurality of codewords are generated, and a first parity sector is generated over the first plurality of codewords. The first plurality of codewords and the first parity sector are written to the first data segment. A second plurality of codewords are generated, and a second parity sector is generated over the second plurality of codewords. The second plurality of codewords and the second parity sector are written to the second data segment. During a read operation the data segments of the data track are processed sequentially to decode the codewords using a low density parity check (LDPC) decoder, wherein the reliability metrics of un-converged codewords are stored in a codeword buffer and updated using the respective parity sector.
    Type: Application
    Filed: May 17, 2018
    Publication date: November 21, 2019
    Inventors: IOURI OBOUKHOV, WELDON M. HANSON, NIRANJAY RAVINDRAN, RICHARD L. GALBRAITH
  • Patent number: 10417089
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). A reliability metric for each symbol of each of a plurality of codewords read from the NVSM is generated, and a number of erasures for a first codeword are generated, wherein the number of erasures exceeds the correction power of the first codeword. A reliability metric of the first codeword is modified corresponding to one of the erasures. The reliability metrics for each codeword including the modified reliability metrics of the first codeword are first iteratively processed using a low density parity check (LDPC) type decoder, thereby first updating the reliability metric for each symbol of each codeword. The reliability metrics for the first codeword are second updated using the parity sector, and the second updated reliability metrics for the first codeword are second iteratively processed using the LDPC-type decoder.
    Type: Grant
    Filed: February 13, 2018
    Date of Patent: September 17, 2019
    Assignee: Western Digital Technologies, Inc.
    Inventors: Iouri Oboukhov, Weldon M. Hanson, Niranjay Ravindran, Richard L. Galbraith
  • Publication number: 20190250987
    Abstract: A data storage device is disclosed comprising a non-volatile storage medium (NVSM). A reliability metric for each symbol of each of a plurality of codewords read from the NVSM is generated, and a number of erasures for a first codeword are generated, wherein the number of erasures exceeds the correction power of the first codeword. A reliability metric of the first codeword is modified corresponding to one of the erasures. The reliability metrics for each codeword including the modified reliability metrics of the first codeword are first iteratively processed using a low density parity check (LDPC) type decoder, thereby first updating the reliability metric for each symbol of each codeword. The reliability metrics for the first codeword are second updated using the parity sector, and the second updated reliability metrics for the first codeword are second iteratively processed using the LDPC-type decoder.
    Type: Application
    Filed: February 13, 2018
    Publication date: August 15, 2019
    Inventors: IOURI OBOUKHOV, WELDON M. HANSON, NIRANJAY RAVINDRAN, RICHARD L. GALBRAITH
  • Patent number: 9632863
    Abstract: In general, techniques are described for performing track-error-correcting code on data. A hard drive comprising a storage device and a read channel may be configured to perform the techniques. The read channel may be configured to read data from a track comprising a plurality of data sectors each comprising a plurality of bits, and a parity sector comprising a plurality of parity bits, wherein the data includes a plurality of bit groups, each bit group including a single bit from each data sector, and wherein each parity bit corresponds to a respective bit group, perform a track parity check, and, responsive to determining that the data includes an error, identify one or more data sectors as possible sources of the at least one error and adjust a log-likelihood ratio for at least one bit from the bit group.
    Type: Grant
    Filed: January 13, 2015
    Date of Patent: April 25, 2017
    Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Roger W. Wood
  • Publication number: 20160203041
    Abstract: In general, techniques are described for performing track-error-correcting code on data. A hard drive comprising a storage device and a read channel may be configured to perform the techniques. The read channel may be configured to read data from a track comprising a plurality of data sectors each comprising a plurality of bits, and a parity sector comprising a plurality of parity bits, wherein the data includes a plurality of bit groups, each bit group including a single bit from each data sector, and wherein each parity bit corresponds to a respective bit group, perform a track parity check, and, responsive to determining that the data includes an error, identify one or more data sectors as possible sources of the at least one error and adjust a log-likelihood ratio for at least one bit from the bit group.
    Type: Application
    Filed: January 13, 2015
    Publication date: July 14, 2016
    Inventors: Richard L. Galbraith, Weldon M. Hanson, Roger W. Wood