Patents by Inventor Alain Chahwan

Alain Chahwan 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: 20230306994
    Abstract: Various illustrative aspects are directed to a data storage device comprising data tracks N and N?1, and one or more processing devices, configured to measure signal to noise ratio (SNR) metrics for corresponding sectors of at least one of the data tracks N?1 and N, where the measuring is based at least in part on reading one or more of the data tracks N and N?1 using one or more read offsets, estimate a position of at least one of the data tracks based on measuring the one or more SNR metrics, and reconstruct one or more of risk values for at least a portion of the data track N?1 based on the one or more SNR metrics for the data track N?1, and a position error signal (PES) for at least one of the data tracks N?1 and N based on the corresponding estimated positions.
    Type: Application
    Filed: March 24, 2022
    Publication date: September 28, 2023
    Inventors: Weldon M. Hanson, Alain Chahwan, Niranjay Ravindran
  • Patent number: 11756581
    Abstract: Various illustrative aspects are directed to a data storage device comprising data tracks N and N?1, and one or more processing devices, configured to measure signal to noise ratio (SNR) metrics for corresponding sectors of at least one of the data tracks N?1 and N, where the measuring is based at least in part on reading one or more of the data tracks N and N?1 using one or more read offsets, estimate a position of at least one of the data tracks based on measuring the one or more SNR metrics, and reconstruct one or more of risk values for at least a portion of the data track N?1 based on the one or more SNR metrics for the data track N?1, and a position error signal (PES) for at least one of the data tracks N?1 and N based on the corresponding estimated positions.
    Type: Grant
    Filed: March 24, 2022
    Date of Patent: September 12, 2023
    Assignee: Western Digital Technologies, Inc.
    Inventors: Weldon M. Hanson, Alain Chahwan, Niranjay Ravindran
  • Patent number: 10748568
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising servo data for defining a plurality of data tracks, including consecutive data tracks N?1, N, and N+1. Data is written to data track N using a position error signal (PES) generated by reading the servo data, and a read track trajectory for data track N is generated based on the PES of the write. Data is read from data track N based on the read track trajectory for data track N.
    Type: Grant
    Filed: August 6, 2019
    Date of Patent: August 18, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Niranjay Ravindran
  • Patent number: 10748567
    Abstract: A data storage device is disclosed comprising a head actuated over a disk comprising a plurality of data tracks, including consecutive data tracks N?1 and N. A first write to data track N is performed using a first position error signal (PES) representing a position of the head relative to the data tracks. A track squeeze metric is generated for data track N?1 based on at least the first PES of the first write. The track squeeze metric for data track N?1 is accumulated during the first write, and the first write is aborted when the accumulated track squeeze metric for data track N?1 exceeds a first threshold.
    Type: Grant
    Filed: October 17, 2019
    Date of Patent: August 18, 2020
    Assignee: Western Digital Technologies, Inc.
    Inventors: Hideki Zaitsu, Niranjay Ravindran, So Ogiwara, Toshihisa Komai, Alain Chahwan, Weldon M. Hanson
  • Publication number: 20180074728
    Abstract: A device adapted to capture surveillance data that includes a disk and a Non-Volatile Solid-State Memory (NVSM). The surveillance data is received in a buffer of the device for storage on the disk, and an input is received indicating a level of mechanical shock. It is determined whether the input indicates the level of mechanical shock exceeds a first threshold indicative of an impact. If the input indicates the level of mechanical shock exceeds the first threshold, the surveillance data is stored in the NVSM from the buffer and a status is determined for storing data on the disk.
    Type: Application
    Filed: November 20, 2017
    Publication date: March 15, 2018
    Inventors: Alain Chahwan, Choo-Bhin Ong, Meiman L. Syu, Kevin C. Chao
  • Patent number: 9823859
    Abstract: A device adapted to capture vehicle data or surveillance data that includes a disk and a Non-Volatile Solid-State Memory (NVSM). The vehicle or surveillance data is received in a buffer of the device for storage on the disk, and an input is received indicating a level of mechanical shock. It is determined whether the input indicates the level of mechanical shock exceeds a first threshold indicative of an impact. If the input indicates the level of mechanical shock exceeds the first threshold, the vehicle or surveillance data is stored in the NVSM from the buffer and a status is determined for storing data on the disk.
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: November 21, 2017
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Choo-Bhin Ong, Meiman Lin Syu, Kevin Chiteh Chao
  • Patent number: 9401165
    Abstract: A method and system to monitor stability of magnetic head loading and unloading beside media for a data storage system is described. A shock sensor is utilized to detect shock during preloading of a magnetic head beside recording media, during loading of a magnetic head beside recording media, during pre-unloading of a magnetic head from the recording media, and/or during unloading of a magnetic head from the recording media. In an aspect, a desired pitch static attitude (PSA) and roll static attitude (RSA) of a slider is determined. In an aspect, the stability of a magnetic head is assessed and screened while on the fly and during head gimbal assembly (HGA) design and testing to improve overall data storage device reliability.
    Type: Grant
    Filed: June 13, 2014
    Date of Patent: July 26, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jifang Tian, Alain Chahwan
  • Publication number: 20160132257
    Abstract: A device adapted to capture vehicle data or surveillance data that includes a disk and a Non-Volatile Solid-State Memory (NVSM). The vehicle or surveillance data is received in a buffer of the device for storage on the disk, and an input is received indicating a level of mechanical shock. It is determined whether the input indicates the level of mechanical shock exceeds a first threshold indicative of an impact. If the input indicates the level of mechanical shock exceeds the first threshold, the vehicle or surveillance data is stored in the NVSM from the buffer and a status is determined for storing data on the disk.
    Type: Application
    Filed: March 27, 2015
    Publication date: May 12, 2016
    Inventors: ALAIN CHAHWAN, CHOO-BHIN ONG, MEIMAN LIN SYU, KEVIN CHITEH CHAO
  • Patent number: 9274966
    Abstract: Example implementations described herein are related to methods for dynamically throttling host commands (up or down) to disk drives that include cache memory and rotating media, based on environmental conditions and/or drain rate from the cache memory to the rotating media, to provide consistent throughput for extended periods of time, and to avoid dramatic swings in performance from the pre-saturation state to the post-saturation state. The example implementations may be further extended to dynamically throttling host commands to devices that have HDD and SSD portions.
    Type: Grant
    Filed: February 20, 2013
    Date of Patent: March 1, 2016
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Jonathan V. Nguyen
  • Patent number: 9053724
    Abstract: A disk drive is disclosed comprising a first disk surface and a second disk surface, a first head operable to be positioned over the first disk surface, a second head operable to be positioned over the second disk surface, a first microactuator operable to actuate the first head, and a second microactuator operable to actuate the second head. The first head is actuated over the first disk surface using the first microactuator while processing a second sensor signal generated by the second microactuator, and the second head is actuated over the second disk surface using the second microactuator while processing a first sensor signal generated by the first microactuator.
    Type: Grant
    Filed: September 11, 2013
    Date of Patent: June 9, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Mingji Lou
  • Patent number: 9013825
    Abstract: An apparatus includes: a media; a head assembly over the media; a head actuation motor coupled to the head assembly; control circuitry, coupled to the head actuation motor, configured to position the head assembly; and a microphone, coupled to the control circuitry, configured to generate a signal in response to a vibration; and wherein: the control circuitry is further configured to: generate a compensation value based on the signal; and control the head actuator motor based on the compensation value.
    Type: Grant
    Filed: June 20, 2014
    Date of Patent: April 21, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventor: Alain Chahwan
  • Patent number: 9009455
    Abstract: A computer system is disclosed comprising a disk drive comprising a head stack assembly (HSA), the HSA comprising a spindle motor for rotating at least one disk, and at least one head actuated over the disk. The computer system further comprises a host coupled to the disk drive, wherein the host comprises a microprocessor operable to first boot the host by reading boot data from a secondary storage device. After first booting the host, the microprocessor commands the disk drive to accumulate performance data for the HSA, and after accumulating the performance data, the microprocessor second boots the host by reading boot data from the HSA.
    Type: Grant
    Filed: May 3, 2011
    Date of Patent: April 14, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Mingji Lou, Alain Chahwan
  • Patent number: 8953278
    Abstract: A disk drive is disclosed comprising a disk, a head, and control circuitry comprising a servo control system operable to actuate the head over the disk. A plurality of disturbance signals is generated in response to a vibration. A plurality of correlations is generated in response to each disturbance signal and an error signal of the servo control system. At least one of the disturbance signals is selected in response to the correlations. A feed-forward compensation value is generated in response to the selected disturbance signal, and the feed-forward compensation value is applied to the servo control system to compensate for the vibration.
    Type: Grant
    Filed: April 15, 2014
    Date of Patent: February 10, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Jianguo Zhou, Wei Xi, Kuang-Yang Tu, Alain Chahwan
  • Patent number: 8947819
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, and control circuitry comprising a first shock detector and a second shock detector. A first number of shock events is detected based on the first shock detector, and when the first number of shock events exceeds an upper event threshold, a sensitivity of the first shock detector is decreased. After decreasing the sensitivity of the first shock detector, a second number of shock events is detected based on the second shock detector operating at a higher sensitivity than the first shock detector. When the second number of shock events falls below a lower event threshold, the sensitivity of the first shock detector is increased.
    Type: Grant
    Filed: October 15, 2013
    Date of Patent: February 3, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Timothy A. Ferris, Alain Chahwan
  • Patent number: 8929022
    Abstract: A disk drive is disclosed comprising, a head, a disk surface, and a dual stage actuator (DSA) servo loop comprising a voice coil motor (VCM) servo loop comprising a VCM and a microactuator servo loop comprising a microactuator operable to actuate the head over the disk surface. A frequency component of a servo signal in the DSA servo loop is evaluated, wherein the frequency component is based on a peak frequency of an error rejection curve of the DSA servo loop. A degradation of the microactuator is detected based on the frequency component of the servo signal.
    Type: Grant
    Filed: December 19, 2012
    Date of Patent: January 6, 2015
    Assignee: Western Digital Technologies, Inc.
    Inventors: Yanan Huang, Shan Tang, Duc T. Phan, Chuanwen Ji, Alain Chahwan
  • Patent number: 8922937
    Abstract: A disk drive is disclosed comprising a head actuated over a disk, and control circuitry including a vibration sensor. A position error signal (PES) is generated representing a radial location of the head over the disk, and the head is servoed radially over the disk in response to the PES. A first vibration signal is generated in response to the vibration sensor, and a second vibration signal in response to the PES. The first vibration signal is combined with the second vibration signal to generate a third vibration signal, and a vibration event is detected in response to the third vibration signal.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: December 30, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Orhan Beker, Chuanwen Ji
  • Patent number: 8922931
    Abstract: A disk drive is disclosed wherein N data wedges of write data are buffered in a buffer. After writing at least two of the data wedges to the disk including a first data wedge and a second data wedge, a first servo metric value is measured when reading a first servo sector, and a second servo metric value is predicted based on the first servo metric value, wherein the second servo metric value corresponds to a second servo sector following the first servo sector. When the first servo metric value indicates a safe write condition and the second servo metric value indicates an unsafe write condition, the first data wedge is released from the buffer, and when the first servo metric value indicates a safe write condition and the second servo metric value indicates a safe write condition, the first and second data wedges are released from the buffer.
    Type: Grant
    Filed: June 26, 2013
    Date of Patent: December 30, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Chuanwen Ji, Alain Chahwan, Orhan Beker, Yanan Huang, Duc T. Phan
  • Patent number: 8913338
    Abstract: A disk drive is disclosed comprising a disk comprising a plurality of servo tracks defined by servo sectors, wherein each servo sector comprises servo data and a servo compensation value. While servoing a head over a target data track during a write operation, a position error signal (PES) is generated at each servo sector based at least in part on the servo data. When the servo compensation value of a first servo sector is recoverable, the write operation is aborted when the PES generated at the first servo sector exceeds a first write unsafe threshold. When the servo compensation value of the first servo sector is unrecoverable, the write operation is aborted when the PES generated at the first servo sector exceeds a second write unsafe threshold less than the first write unsafe threshold.
    Type: Grant
    Filed: June 24, 2013
    Date of Patent: December 16, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Yanan Huang, Chuanwen Ji
  • Patent number: 8896955
    Abstract: A disk drive comprises a track follow control system having a plurality of selectable frequency modes, the track follow control system configured to receive a position error signal and to output a control signal based on the position error signal, wherein the control signal is used by a head assembly to position a head over a disk. The disk drive also comprises a state estimator configured to receive the control signal and a position signal indicating a position of the head, to estimate a disturbance based on the control signal and the position signal, and to output an estimated disturbance signal based on the estimated disturbance. The disk drive further comprises a disturbance evaluator configured to receive the estimated disturbance signal, and to select one of the frequency modes of the track follow control system based on the estimated disturbance signal.
    Type: Grant
    Filed: June 16, 2011
    Date of Patent: November 25, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Min Chen, Alain Chahwan, Shang-Chen Wu, Qixing Zheng, Alexander Babinski, Duc T. Phan
  • Patent number: 8885283
    Abstract: A disk drive is disclosed comprising a head actuated over a disk having a plurality of data tracks. A vibration is detected, and a write operation is configured to write a first plurality of blocks and a second plurality of blocks to a target data track based on the detected vibration. The first plurality of blocks are written to the target data track during a first revolution of the disk, and the second plurality of blocks are written to the target data track during a second revolution of the disk.
    Type: Grant
    Filed: November 3, 2011
    Date of Patent: November 11, 2014
    Assignee: Western Digital Technologies, Inc.
    Inventors: Alain Chahwan, Jianguo Zhou, Wei Xi