Patents by Inventor Roger William Wood
Roger William Wood 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).
-
Patent number: 10404290Abstract: A method and data storage system receives a confidence vector for a non-binary symbol value read from a memory cell of a non-volatile memory device, where the confidence vector includes a first plurality of confidence values and transforms the first plurality of confidence values into a first plurality of likelihood values using a forward tensor-product transform. A respective binary message passing decoding operation is performed with each of the first plurality of likelihood values to generate a second plurality of likelihood values, and the second plurality of likelihood values are transformed into a second plurality of confidence values of the confidence vector using a reverse tensor-product transform.Type: GrantFiled: July 31, 2017Date of Patent: September 3, 2019Assignee: Western Digital Technologies, Inc.Inventors: Richard Leo Galbraith, Niranjay Ravindran, Roger William Wood
-
Patent number: 10008229Abstract: A method, apparatus, and system are provided for implementing track following using signal asymmetry metrics monitored during read back in hard disk drives (HDDs). Signal asymmetry metrics monitored during read back are used together with a position error signal (PES) to correct and guide the position of a read sensor with respect to a written track in the HDD.Type: GrantFiled: January 5, 2016Date of Patent: June 26, 2018Assignee: WESTERN DIGITAL TECHNOLOGIES, INCInventors: Richard Leo Galbraith, Weldon Mark Hanson, Mark A. Nichols, Alexander Taratorin, Roger William Wood
-
Publication number: 20180034484Abstract: A method and data storage system receives a confidence vector for a non-binary symbol value read from a memory cell of a non-volatile memory device, where the confidence vector includes a first plurality of confidence values and transforms the first plurality of confidence values into a first plurality of likelihood values using a forward tensor-product transform. A respective binary message passing decoding operation is performed with each of the first plurality of likelihood values to generate a second plurality of likelihood values, and the second plurality of likelihood values are transformed into a second plurality of confidence values of the confidence vector using a reverse tensor-product transform.Type: ApplicationFiled: July 31, 2017Publication date: February 1, 2018Inventors: Richard Leo GALBRAITH, Niranjay RAVINDRAN, Roger William WOOD
-
Patent number: 9818440Abstract: According to one embodiment, a heat assisted magnetic recording system includes a magnetic recording medium comprising a magnetic recording layer, where the magnetic recording layer includes a plurality of physical bits. Each physical bit has a perpendicular magnetic anisotropy and one of at least three magnetic states, where the at least three magnetic states include a +1 magnetic state, a 0 magnetic state, and a ?1 magnetic state.Type: GrantFiled: June 27, 2016Date of Patent: November 14, 2017Assignee: WESTERN DIGITAL TECHNOLOGIES, INC.Inventors: Pierre-Olivier Jubert, Michael Konrad Grobis, Richard Leo Galbraith, Roger William Wood
-
Publication number: 20170194024Abstract: A method, apparatus, and system are provided for implementing track following using signal asymmetry metrics monitored during read back in hard disk drives (HDDs). Signal asymmetry metrics monitored during read back are used together with a position error signal (PES) to correct and guide the position of a read sensor with respect to a written track in the HDD.Type: ApplicationFiled: January 5, 2016Publication date: July 6, 2017Inventors: Richard Leo Galbraith, Weldon Mark Hanson, Mark A. Nichols, Alexander Taratorin, Roger William Wood
-
Patent number: 9601144Abstract: A heat-assisted magnetic recording (HAMR) disk drive has a disk with at least two independent data layers (RL1 and RL2), each data layer storing an independent data stream. At a high laser power both RL1 and RL2 are heated to above their respective Curie temperatures and a first data stream is recorded in both RL1 and RL2. At a lower laser power only upper RL2 is heated to above its Curie temperature and a second data stream is recorded only in RL2. The data layers are separated by a nonmagnetic spacer layer (SL) that prevents lower RL1 from being heated to above its Curie temperature at low laser power. The first and second data streams are typically asynchronous. Recorded data is read back from both data streams simultaneously as a composite readback signal. A joint Viterbi detector detects the asynchronous data streams simultaneously from the composite readback signal.Type: GrantFiled: May 25, 2016Date of Patent: March 21, 2017Assignee: HGST Netherlands B.V.Inventors: Virat Vasav Mehta, James William Reiner, Michael Paul Salo, Roger William Wood
-
Patent number: 9437232Abstract: A hard disk drive is adapted to take the most recent estimated read head positions (the position error signal or PES values) that are obtained during writing and write those values into the data sectors as written PES (WPES) values. The WPES values are available on readback for use as a predictor of the positions in which subsequent data sectors were written and are also available for use in a data recovery procedure should a particular data sector fail to be recovered. In two-dimensional magnetic recording, the difference between the WPES value and the read PES value is a quantity required to rapidly select the best 2D equalizer. The PES values may be encoded prior to being written into the data sectors. The WPES values are appended to the data sectors after the preamble and sync fields, which occur after every servo sector.Type: GrantFiled: July 15, 2015Date of Patent: September 6, 2016Assignee: HGST Netherlands B.V.Inventors: Richard Leo Galbraith, Weldon Mark Hanson, Roger William Wood
-
Patent number: 9218847Abstract: A method of testing a one or more components of a data storage system introduces a first plurality of micro-transitions into a first data write pattern, which is then written to a magnetic media. A read-back signal is generated, and a frequency response of the read-back signal is analyzed to determine performance of the one or more components of the data storage system.Type: GrantFiled: December 18, 2013Date of Patent: December 22, 2015Assignee: HGST NETHERLANDS B.V.Inventors: Weldon Mark Hanson, Michael Paul Salo, Alexander Taratorin, Roger William Wood
-
Publication number: 20150170707Abstract: A method of testing a one or more components of a data storage system introduces a first plurality of micro-transitions into a first data write pattern, which is then written to a magnetic media. A read-back signal is generated, and a frequency response of the read-back signal is analyzed to determine performance of the one or more components of the data storage system.Type: ApplicationFiled: December 18, 2013Publication date: June 18, 2015Applicant: HGST Netherlands B.V.Inventors: Weldon Mark HANSON, Michael Paul SALO, Alexander TARATORIN, Roger William WOOD
-
Patent number: 9059737Abstract: Disk drives are described in which blocks of data spanning multiple sectors are encoded into a plurality of codewords which are then divided into segments that are physically separated (distributed) on the disk surface over multiple sectors in a distributed codeword block so that the codewords have an improved worst case SNR in comparison to individual sectors. This results in more even SNR performance for each codeword, which improves the performance for portions of a track which have lower than the average SNR. Embodiments are described in which the distributed codeword blocks span across tracks.Type: GrantFiled: May 1, 2013Date of Patent: June 16, 2015Assignee: HGST Netherlands B.V.Inventors: Jonathan Darrel Coker, Richard Leo Galbraith, Weldon Mark Hanson, Travis Roger Oenning, Roger William Wood
-
Patent number: 9036304Abstract: A dual-stack read sensor is utilized in a storage device having an actuator arm that positions the read sensor over a rotating storage medium. The dual-stacked read sensor includes a primary read sensor having a first set of read sensor characteristics and a secondary read sensor having a second set of read sensor characteristics that differ from the first set of read sensor characteristics, wherein the secondary read sensor is positioned relative to the primary read sensor to be radially offset from the primary read sensor relative to a data track being read.Type: GrantFiled: May 19, 2014Date of Patent: May 19, 2015Assignee: HGST NETHERLANDS B.V.Inventors: Richard Leo Galbraith, Roger William Wood
-
Publication number: 20150116860Abstract: Techniques for processing signals read-back from a disk of a hard disk drive are described. In one example, a hard disk drive device generates a signal associated with a first position within a width of the data track. The first position may correspond to the center of a data track. The hard disk drive device generates a signal associated with a second position within a width of the data track. The second position may be located at a distance of approximately 10% of the track width from the track center. The hard disk drive device combines the signals and applies as signal conditioning technique to the combined signal.Type: ApplicationFiled: October 28, 2013Publication date: April 30, 2015Applicant: HGST Netherlands B.V.Inventors: Jonathan Darrel COKER, Richard Leo GALBRAITH, Travis Roger OENNING, Roger William WOOD
-
Patent number: 8902534Abstract: A method, apparatus and a data storage device are provided for implementing track following and data recovery with readback of shingled data written in overlapping shingled data tracks on a recordable surface of a storage device. Positional information is identified with data readback of shingled data written in overlapping shingled data tracks. The identified positional information is used to selectively modify at least one predefined channel parameter, for example, to provide enhanced track following and enhanced data recovery.Type: GrantFiled: August 3, 2012Date of Patent: December 2, 2014Assignee: HGST Netherlands B.V.Inventors: Richard Michael Brockie, Richard Leo Galbraith, Petrus Antonius Van Der Heijden, Roger William Wood
-
Patent number: 8856618Abstract: A technique for recovering of “squeezed” sectors in a set of sequential sectors such as are used in Shingled Magnetic Recording (SMR) is described. Embodiments of the invention use a programmable erased sector recovery scheme, which is a concatenation of a “Cauchy-type” track erasure correction code, together with a media-error correction code that generates N-weighted parity-sectors per track and is capable of replacing up to N-erased sectors per track in any possible combination.Type: GrantFiled: October 4, 2012Date of Patent: October 7, 2014Assignee: HGST Netherlands B.V.Inventors: Kei Akiyama, Sridhar Chatradhi, Jonathan Darrel Coker, Martin Aureliano Hassner, Kirk Hwang, Roger William Wood
-
Publication number: 20140201590Abstract: Disk drives are described in which blocks of data spanning multiple sectors are encoded into a plurality of codewords which are then divided into segments that are physically separated (distributed) on the disk surface over multiple sectors in a distributed codeword block so that the codewords have an improved worst case SNR in comparison to individual sectors. This results in more even SNR performance for each codeword, which improves the performance for portions of a track which have lower than the average SNR. Embodiments are described in which the distributed codeword blocks span across tracks.Type: ApplicationFiled: May 1, 2013Publication date: July 17, 2014Applicant: HGST Netherlands B.V.Inventors: Jonathan Darrel Coker, Richard Leo Galbraith, Weldon Mark Hanson, Travis Roger Oenning, Roger William Wood
-
Publication number: 20140101515Abstract: A technique for recovering of “squeezed” sectors in a set of sequential sectors such as are used in Shingled Magnetic Recording (SMR) is described. Embodiments of the invention use a programmable erased sector recovery scheme, which is a concatenation of a “Cauchy-type” track erasure correction code, together with a media-error correction code that generates N-weighted parity-sectors per track and is capable of replacing up to N-erased sectors per track in any possible combination.Type: ApplicationFiled: October 4, 2012Publication date: April 10, 2014Applicant: HGST NETHERLANDS B.V.Inventors: Kei Akiyama, Sridhar Chatradhi, Jonathan Darrel Coker, Martin Aureliano Hassner, Kirk Hwang, Roger William Wood
-
Patent number: 8665545Abstract: A “write-squeeze-verify” method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus “squeezes” the data of the previously written track to thereby form a “shingled data track” (SDT). The data in each SDT is read back and verified by an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a “re-try fail” is reported.Type: GrantFiled: December 12, 2011Date of Patent: March 4, 2014Assignee: HGST Netherlands B.V.Inventors: Jonathan Darrel Coker, Martin Aureliano Hassner, Kirk Hwang, Bruce Alexander Wilson, Roger William Wood
-
Publication number: 20140036381Abstract: A method, apparatus and a data storage device are provided for implementing track following and data recovery with readback of shingled data written in overlapping shingled data tracks on a recordable surface of a storage device. Positional information is identified with data readback of shingled data written in overlapping shingled data tracks. The identified positional information is used to selectively modify at least one predefined channel parameter, for example, to provide enhanced track following and enhanced data recovery.Type: ApplicationFiled: August 3, 2012Publication date: February 6, 2014Applicant: HGST NETHERLANDS B.V.Inventors: Richard Michael Brockie, Richard Leo Galbraith, Petrus Antonius Van Der Heijden, Roger William Wood
-
Publication number: 20130148225Abstract: A “write-squeeze-verify” method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus “squeezes” the data of the previously written track to thereby form a “shingled data track” (SDT). The data in each SDT is read back and verified by performing an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a “re-try fail” is reported.Type: ApplicationFiled: December 12, 2011Publication date: June 13, 2013Inventors: Jonathan Darrel Coker, Martin Aureliano Hassner, Kirk Hwang, Bruce Alexander Wilson, Roger William Wood
-
Patent number: 8094403Abstract: A hard-disk drive (HDD) with a current adjustment component is provided. The current adjustment component changes an amount of current to a magnetic-recording head of the HDD to cause a change in the strength of a magnetic write field produced by the magnetic-recording head in response to a determination that a present position of the magnetic-head head is not in a desired position. To illustrate, in response to a determination that the present position of the magnetic-recording head is further away from an edge of a current track being written than a desired position of the magnetic-recording head, the current adjustment component increases the current to the magnetic-recording head to cause an increase in the strength of the magnetic write field. The change in the strength of the magnetic write field causes data, written by the magnetic-recording head, to be located at a desired location on the magnetic-recording disk.Type: GrantFiled: May 4, 2009Date of Patent: January 10, 2012Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventors: Roger William Wood, James Terrence Olson, Zhen Jin, Michael Paul Salo