Patents by Inventor Nhan Bui

Nhan Bui 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: 20110007418
    Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism.
    Type: Application
    Filed: September 9, 2010
    Publication date: January 13, 2011
    Applicant: IBM CORPORATION
    Inventors: Nhan Bui, Giovanni Cherubini, Roy D. Cideciyan, Robert A. Hutchins, Jens Jelitto, Kazuhiro Tsuruta
  • Publication number: 20100328803
    Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism.
    Type: Application
    Filed: September 9, 2010
    Publication date: December 30, 2010
    Applicant: IBM CORPORATION
    Inventors: Nhan Bui, Giovanni Cherubini, Roy D. Cideciyan, Robert A. Hutchins, Jens Jelitto, Kazuhiro Tsuruta
  • Publication number: 20100226039
    Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module comprises two synchronous servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted parameter estimate and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. An offset computation module provides first and second offset terms which are summed with the unweighted parameter estimates. Multiplying nodes receive the unweighted parameter estimates and the weight signals and outputs offset weighted parameter estimates. A summing node receives the offset weighted parameter estimates and outputs a combined offset weighted parameter estimate to a servomechanism.
    Type: Application
    Filed: March 9, 2009
    Publication date: September 9, 2010
    Applicant: IBM Corporation
    Inventors: Nhan Bui, Giovanni Cherubini, Roy D. Cideciyan, Robert A. Hutchins, Jens Jelitto, Kazuhiro Tsuruta
  • Publication number: 20100226037
    Abstract: A weighted combining scheme exploits information from two servo channels operating in parallel. A timing-based servo module servo module comprises two servo channels coupled respectively to receive two digital servo signals read from a data tape. Both channels have outputs for an unweighted metric and for a measure of the channel reliability. A weight computation module provides first and second weight signals using the measures of channel reliability from the servo channels. A first multiplying node receives a first unweighted metric and a first weight signal and is operable to output a first weighted metric. A second multiplying node receives a second unweighted metric and a second weight signal and outputs a second weighted metric. A summing node receives the first and second weighted metrics and outputs a combined weighted metric to an LPOS word decoder.
    Type: Application
    Filed: March 9, 2009
    Publication date: September 9, 2010
    Applicant: IBM Corporation
    Inventors: Nhan Bui, Giovanni Cherubini, Roy D. Cideciyan, Robert A. Hutchins, Jens Jelitto, Kazuhiro Tsuruta
  • Publication number: 20080117539
    Abstract: A magnetic tape cartridge including magnetic tape with servo information is provided. The servo information comprises a plurality of parallel longitudinal servo bands that lie between a plurality of longitudinal data bands. The plurality of servo bands include odd servo bands and even servo bands, wherein each of the odd servo bands lie between each of the even servo bands. Each of the plurality servo bands include a plurality of frames, wherein each frame includes a plurality of bursts of transition stripes, and each burst having a first transition stripe. The first transition stripe of each burst of each the odd servo band is longitudinally shifted from the first transition stripe of each burst of each even servo band by a substantially equal distance, D, such that servo information of the odd servo bands is interleaved with the servo information from the even servo bands.
    Type: Application
    Filed: February 1, 2008
    Publication date: May 22, 2008
    Applicant: IBM CORPORATION
    Inventors: Nhan Bui, Reed Hancock, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20080117543
    Abstract: A tape drive and a method of using a tape drive is provided. The tape drive includes a head assembly including at least a first and a second servo read element configured to detect transition stripes of a servo pattern on tape media. The first servo read element is configured to detect at least two transition stripes of an even servo band on the tape media at a first time. The servo detection logic is configured to detect a timing of at least two transition stripes of the even servo band on the tape media. The servo controller is configured to position the head assembly laterally with respect to the tape media in response to the timing of the at least two transition stripes of the even servo band on the tape media. The second servo read element is configured to detect at least two transition stripes of an odd servo band on the tape media at a second time, wherein the second time is a time delay after the first time corresponding to a distance D.
    Type: Application
    Filed: February 1, 2008
    Publication date: May 22, 2008
    Applicant: IBM CORPORATION
    Inventors: Nhan Bui, Reed Hancock, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20080117542
    Abstract: A method and a system are provided for writing a plurality of servo bands on magnetic tape. The magnetic tape is moved longitudinally relative to at least one servo write head. The servo write head is positioned to write a plurality of parallel longitudinal servo bands. The plurality of servo bands comprise odd servo bands and even servo bands, and each of the odd servo bands lie between the each of the even servo bands. The at least one servo write head is operated to write the plurality of parallel longitudinal servo bands on the magnetic tape such that each of the plurality of servo bands comprise a plurality of frames, wherein each frame comprises a plurality of bursts of transition stripes, and each burst has a first transition stripe.
    Type: Application
    Filed: February 1, 2008
    Publication date: May 22, 2008
    Applicant: IBM CORPORATION
    Inventors: Nhan Bui, Reed Hancock, Eiji Ogura, Kazuhiro Tsuruta
  • Patent number: 7362537
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a velocity adaptive compensator for a synchronous sampling servo control system.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: April 22, 2008
    Assignee: International Business Machines Corporation
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Patent number: 7280307
    Abstract: A magnetic tape drive, having a compound servo actuator, reduces the possibility of overshoots of servo elements when a tape cartridge is loaded, thereby reducing servo failures. The coarse motor is activated, then deactivated when the servo elements locate a servo pattern on the tape. After initialization of a DAC offset in the servo controller to 0, the position of the fine actuator is read. The fine actuator is enabled, with a DAC input of 0 and, after a short wait, the position is again read. The new DAC offset equals the initial DAC offset plus the difference between the two positions. If the difference is less than a predetermined threshold, the servo controller may obtain a lock on the servo signals and commence tracking. If the difference is not less, the process is repeated, with the DAC offset being adjusted each time, until the difference is less than a predetermined threshold.
    Type: Grant
    Filed: February 10, 2006
    Date of Patent: October 9, 2007
    Assignee: International Business Machines Corporation
    Inventors: Nhan Bui, Ernest Gale, Eiji Ogura, Kazuhiro Tsuruta
  • Patent number: 7265935
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a velocity adaptive compensator for a synchronous sampling servo control system.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: September 4, 2007
    Assignee: International Business Machines Corporation
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20070188910
    Abstract: A magnetic tape drive, having a compound servo actuator, reduces the possibility of overshoots of servo elements when a tape cartridge is loaded, thereby reducing servo failures. The coarse motor is activated, then deactivated when the servo elements locate a servo pattern on the tape. After initialization of a DAC offset in the servo controller to 0, the position of the fine actuator is read. The fine actuator is enabled, with a DAC input of 0 and, after a short wait, the position is again read. The new DAC offset equals the initial DAC offset plus the difference between the two positions. If the difference is less than a predetermined threshold, the servo controller may obtain a lock on the servo signals and commence tracking. If the difference is not less, the process is repeated, with the DAC offset being adjusted each time, until the difference is less than a predetermined threshold.
    Type: Application
    Filed: February 10, 2006
    Publication date: August 16, 2007
    Applicant: International Business Machines Corporation
    Inventors: Nhan Bui, Ernest Gale, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20070187540
    Abstract: Disclosed are a system, a method, and an article of manufacture to provide for the detection and compensation of tape breakage in a tape drive. The invention operates by simultaneously monitoring the tape reel rotation direction and the ratio of rotation between the tape reels. If the rotation direction is not the same for both reels, then tape breakage is indicated and reel rotation ceases. Tape breakage is also detected if the tape reel angular rotation ratio between the supply and take up reels is not within a specified tape reel ratio range. The tape reel angular rotation ratio is detected by simultaneously measuring the angular rotation of each tape reel in a specified time period and then calculating the ratio. The present invention detects the tape reel angular rotation ratio and if tape reel angular rotation ratio is outside of the specified tape reel ratio range, tape breakage is indicated and reel rotation ceases.
    Type: Application
    Filed: February 13, 2007
    Publication date: August 16, 2007
    Inventors: Nhan Bui, Junichi Fukuda, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20070177292
    Abstract: Provided is a read channel, storage drive, and method to process signals read from a storage medium. At least one data channel including an interpolator and equalizer and a servo channel includes an interpolator. A timing recovery function processes a timing error from the interpolator in the servo channel to calculate interpolation timing information used by the interpolator to interpolate a servo channel signal. A path is coupled to the timing recovery function and the interpolator in the at least one data channel to communicate the interpolation timing information to the interpolator in the at least one data channel. The interpolator in the at least one data channel is configured to use the interpolation timing information to interpolate an asynchronous data channel signal.
    Type: Application
    Filed: February 1, 2006
    Publication date: August 2, 2007
    Inventors: Nhan Bui, Giovanni Cherubini, Evangelos Eleftheriou, Robert Hutchins, Glen Jaquette, Jens Jelitto, Sedat Oelcer, Mark Taylor
  • Publication number: 20070115581
    Abstract: Selection of servo signals for peak detection of timing based servo tracks of magnetic tape for lateral positioning of heads relative to the magnetic tape. Servo signals from magneto-resistive servo read head(s) reading a magnetic tape are digitized by analog to digital converter(s); digital peak measurement apparatus is configured to sense the digital converter(s), and provide positive peak values and negative peak values of the digitized servo signals; and control apparatus is configured to determine the greater of the provided positive peak values or negative peak values, and select servo signals having the greater values for a servo channel. Servo apparatus is configured to respond to the selected servo signals to control the lateral positioning of the servo read head(s).
    Type: Application
    Filed: November 22, 2005
    Publication date: May 24, 2007
    Inventors: Nhan Bui, Ernest Gale, Eiji Ogura, David Swanson
  • Publication number: 20060245104
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a velocity adaptive compensator for a synchronous sampling servo control system.
    Type: Application
    Filed: June 28, 2006
    Publication date: November 2, 2006
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Patent number: 7110212
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a compensator for a synchronous sampling servo control system.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: September 19, 2006
    Assignee: International Business Machines Corporation
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20060126214
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a compensator for a synchronous sampling servo control system.
    Type: Application
    Filed: December 15, 2004
    Publication date: June 15, 2006
    Applicant: International Business Machines Corporation
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20060126215
    Abstract: Disclosed are a system, a method, and article of manufacture to provide a velocity adaptive compensator for a synchronous sampling servo control system.
    Type: Application
    Filed: December 15, 2004
    Publication date: June 15, 2006
    Applicant: International Business Machines Corporation
    Inventors: Nhan Bui, Randy Inch, Eiji Ogura, Kazuhiro Tsuruta
  • Publication number: 20050286158
    Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.
    Type: Application
    Filed: August 29, 2005
    Publication date: December 29, 2005
    Inventors: Nhan Bui, James Eaton, Junichi Fukuda, Glen Jaquette, Eiji Ogura, Mark Taylor, Kazuhiro Tsuruta
  • Publication number: 20050286160
    Abstract: In a tape having separate servo bands of patterns positioned laterally across the tape, the patterns of a separate servo band have at least one differentiating characteristic with respect to patterns of another of the separate servo bands. The differentiating characteristic allows identification of the separate servo bands. For example, the patterns of a separate servo band have differing azimuthal orientations of detectable transitions with respect to another servo band, such as being laterally inverted. In another, variations in the width of gaps of patterns are made with respect to another servo band. In another, variations are made in the number of the detectable transitions of patterns with respect to the patterns of another servo band.
    Type: Application
    Filed: August 29, 2005
    Publication date: December 29, 2005
    Inventors: Nhan Bui, James Eaton, Junichi Fukuda, Glen Jaquette, Eiji Ogura, Mark Taylor, Kazuhiro Tsuruta