Patents by Inventor Masahiko Tsunoda
Masahiko Tsunoda 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: 8169734Abstract: According to one embodiment, a disk drive includes a measuring module, a flying height controller, a detection module, and a controller. The measuring module is configured to measure the flying height that the head has with respect to the disk. The flying height controller is configured to control the head flying height in accordance with a value preset for the head flying height. The detection module is configured to detect the values representing the environmental elements of the head. The controller is configured to adjust the preset value in accordance with the flying height measured by the measuring module and values detected by the detection module if environmental changes are detected from the environmental element values output from the detection module.Type: GrantFiled: November 19, 2010Date of Patent: May 1, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Tsunoda, Aya Tanaka
-
Publication number: 20120087224Abstract: According to one embodiment, a disk drive is provided, which starts reading data at the head thereof, when a sync mark is detected. The disk drive has a read channel that generates a forced SM detection signal if the sync mark cannot be detected because of the occurrence of TA. The read channel starts generating the forced SM detection signal at the end position of a preamble, which is equivalent to the position of the sync mark.Type: ApplicationFiled: December 21, 2011Publication date: April 12, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Aya TANAKA, Masahiko TSUNODA
-
Publication number: 20110211276Abstract: According to one embodiment, a disk drive includes a measuring module, a flying height controller, a detection module, and a controller. The measuring module is configured to measure the flying height that the head has with respect to the disk. The flying height controller is configured to control the head flying height in accordance with a value preset for the head flying height. The detection module is configured to detect the values representing the environmental elements of the head. The controller is configured to adjust the preset value in accordance with the flying height measured by the measuring module and values detected by the detection module if environmental changes are detected from the environmental element values output from the detection module.Type: ApplicationFiled: November 19, 2010Publication date: September 1, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Masahiko Tsunoda, Aya Tanaka
-
Publication number: 20110007415Abstract: According to one embodiment, a disk drive is provided, which starts reading data at the head thereof, when a sync mark is detected. The disk drive has a read channel that generates a forced SM detection signal if the sync mark cannot be detected because of the occurrence of TA. The read channel starts generating the forced SM detection signal at the end position of a preamble, which is equivalent to the position of the sync mark.Type: ApplicationFiled: March 25, 2010Publication date: January 13, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Aya Tanaka, Masahiko Tsunoda
-
Patent number: 7388817Abstract: After the read head of a composite head reads sector data from a disk, a read circuit detects a sync mark in the sector data. The read circuit demodulates user data subsequent to the detected sync mark, and outputs it to a disk controller. A sequencer incorporated in the disk controller measures, as a read preamble data length, the data length of preamble data preceding to the detected sync mark. The sequencer determines the head gap length of the composite head from the data length of the preamble data of sector data to be written to the disk, a write path delay, the read preamble data length and a read path delay.Type: GrantFiled: June 1, 2004Date of Patent: June 17, 2008Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Patent number: 7171607Abstract: When a special write command from a host is executed, switching is performed so that the data designated by the command will not be input to an ECC generator. In accordance with an erasure pointer setting command from the host, a programmable erasure pointer generator sets, in an erasure pointer memory, a special erasure pointer that indicates, as an error location, the location designated by the setting command. This pointer is used for erasure correction performed when the data written to a disk by the execution of the special write command is read in accordance with a normal read command.Type: GrantFiled: December 23, 2003Date of Patent: January 30, 2007Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Publication number: 20050002295Abstract: After the read head of a composite head reads sector data from a disk, a read circuit detects a sync mark in the sector data. The read circuit demodulates user data subsequent to the detected sync mark, and outputs it to a disk controller. A sequencer incorporated in the disk controller measures, as a read preamble data length, the data length of preamble data preceding to the detected sync mark. The sequencer determines the head gap length of the composite head from the data length of the preamble data of sector data to be written to the disk, a write path delay, the read preamble data length and a read path delay.Type: ApplicationFiled: June 1, 2004Publication date: January 6, 2005Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Masahiko Tsunoda
-
Publication number: 20040168102Abstract: When a special write command from a host is executed, switching is performed so that the data designated by the command will not be input to an ECC generator. In accordance with an erasure pointer setting command from the host, a programmable erasure pointer generator sets, in an erasure pointer memory, a special erasure pointer that indicates, as an error location, the location designated by the setting command. This pointer is used for erasure correction performed when the data written to a disk by the execution of the special write command is read in accordance with a normal read command.Type: ApplicationFiled: December 23, 2003Publication date: August 26, 2004Applicant: KABUSHIKI KAISHA TOSHIBAInventor: Masahiko Tsunoda
-
Patent number: 6525891Abstract: A read channel for use in a disk drive having an MR head. The read channel comprises a compensation device which has a high-pass filter (HPF) for compensating a thermal asperity (TA). The read channel suppresses level changes of a data signal which have resulted from TA disturbance present in the data signal. The read channel has a switch circuit connected to the input of the HPF, for canceling the DC undershoot present in the data signal. The switch circuit maintains the DC level of the data signal at zero level while a thermal asperity is being detected in the data signal.Type: GrantFiled: March 6, 2000Date of Patent: February 25, 2003Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Patent number: 6104560Abstract: In a data reproducing device using a read channel of a PRML system, during a period of a continuous reproducing operation mode for continuous reproduction processing of adjacent data sectors, a restart RG generator switches a restart read gate signal RRG ON in synchronization with switching ON of a reference read gate signal RG. Therefore, when data is reproduced from a data sector before continuous data sectors, data reproduction processing is started by means of the restart read gate signal RRG equivalent to the reference read gate signal RG. When data is continuously reproduced from a next data sector adjacent to the previous data sector, the restart RG generator switches the restart read gate signal RRG ON ahead of the reference read gate signal RG by a specified period.Type: GrantFiled: September 29, 1998Date of Patent: August 15, 2000Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Patent number: 6101054Abstract: A read channel for use in a disk drive having an MR head. The read channel comprises a compensation device which has a high-pass filter (HPF) for compensating a thermal asperity (TA). The read channel suppresses level changes of a data signal which have resulted from TA disturbance present in the data signal. The read channel has a switch circuit connected to the input of the HPF, for canceling the DC undershoot present in the data signal. The switch circuit maintains the DC level of the data signal at zero level while a thermal asperity is being detected in the data signal.Type: GrantFiled: July 27, 1999Date of Patent: August 8, 2000Assignee: Kabushiki Kaisha ToshiaInventor: Masahiko Tsunoda
-
Patent number: 6005726Abstract: A read channel for use in a disk drive having an MR head. The read channel comprises a compensation device which has a high-pass filter (HPF) for compensating a thermal asperity (TA). The read channel suppresses level changes of a data signal which have resulted from TA disturbance present in the data signal. The read channel has a switch circuit connected to the input of the HPF, for canceling the DC undershoot present in the data signal. The switch circuit maintains the DC level of the data signal at zero level while a thermal asperity is being detected in the data signal.Type: GrantFiled: July 17, 1997Date of Patent: December 21, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Patent number: 5905601Abstract: In a data reproducing device using a read channel of a PRML system, during a period of a continuous reproducing operation mode for continuous reproduction processing of adjacent data sectors, a restart RG generator switches a restart read gate signal RRG ON in synchronization with switching ON of a reference read gate signal RG. Therefore, when data is reproduced from a data sector before continuous data sectors, data reproduction processing is started by means of the restart read gate signal RRG equivalent to the reference read gate signal RG. When data is continuously reproduced from a next data sector adjacent to the previous data sector, the restart RG generator keeps the restart read gate signal ON for a predetermined period of time before the reference read gate signal RG is generated.Type: GrantFiled: March 11, 1996Date of Patent: May 18, 1999Assignee: Kabushiki Kaisha ToshibaInventor: Masahiko Tsunoda
-
Patent number: 5453888Abstract: In a hard disk drive of a sector servo type, two low pass filters having different filter characteristics are used. One low pass filter has uniform group delay characteristics to accurately detect the peak positions of data read/written by a user without causing any peak shifts. The other low pass filter has attenuation characteristics representing a high degree of attenuation of signal components having frequencies higher than a predetermined frequency so as to accurately detect the amplitudes of burst data for positioning a magnetic head to the center of a destination cylinder by removing noise.Type: GrantFiled: January 18, 1994Date of Patent: September 26, 1995Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Tsunoda, Hiroyuki Kanda
-
Patent number: 5319508Abstract: According to this invention, in a magnetic disk device for recording/reproducing data using a magnetic head, a position of which is controlled by a sector servo method, a tracking speed of an AGC amplifier is set to be a first speed (about 10 .mu.s) in an AGC address area and an AGC burst area, and the tracking speed of the AGC amplifier is set to be a tracking speed (about 20 ms) lower than the first tracking speed in an intersector gap, a gap, a block address area, and a data area.Type: GrantFiled: August 28, 1991Date of Patent: June 7, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Masahiko Tsunoda, Masako Mikada
-
Patent number: 5157560Abstract: A recording and reproducing apparatus having reduced power consumption, wherein a spindle motor drive is stopped during a seek operation while a voice coil motor is driven to move a magnetic head to a destination track on a recording medium. Upon the magnetic head reaching the destination track, the voice coil motor drive is stopped, and the spindle motor is driven.Type: GrantFiled: July 26, 1990Date of Patent: October 20, 1992Assignee: Kabushki Kaisha ToshibaInventors: Hiroyuki Kanda, Masahiko Tsunoda, Akitoshi Iwata