Patents Assigned to Hitachi Global Storage Technologies Japan, Ltd.
  • Patent number: 8345371
    Abstract: An information storing device and an information processing device having a memory for registering a plurality of working modes at recording/reproduction and a switching circuit for selecting one of the plurality of working modes, which select the optimum working mode automatically or by an instruction of an operator according to power supply capacity of a device of higher rank to effect recording/reproduction.
    Type: Grant
    Filed: October 20, 2010
    Date of Patent: January 1, 2013
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yuichi Koizumi, Hideaki Amano, Katsuhiro Tsuneta, Koji Kodama
  • Patent number: 8144415
    Abstract: To effectively suppress a signal in a low frequency region in which the medium noise and the signal distortion are concentrated, and in order to effectively utilize a detected component of the reproduced signal in the low frequency region, a target of partial response equalization to the perpendicularly recorded/reproduced signal is set so that the low-frequency component around the direct current is suppressed to a regulated quantity for both the effective suppression and the effective utilization. Accordingly, a maximum-likelihood decoding process is carried out through the target of partial response equalization. Reliability of data detection is made higher and a signal-to-noise ratio is improved, so that the noise from the recording medium can be reduced more and it is possible to provide a high-density magnetic recording/reproducing apparatus.
    Type: Grant
    Filed: September 14, 2010
    Date of Patent: March 27, 2012
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Hiroyuki Tsuchinaga
  • Patent number: 8117518
    Abstract: In a data recovery processing, the conventional overhead, primarily, latency due to a rotational recording media is removed. Secondary, in a signal processing or in a recording and reproducing apparatus, reliability of data reproduction is improved by repeatedly processing data. These processing are achieved that input signal, i.e., raw analog signal read from the recording media is digitized to be stored in a secondary storage such as a memory or a FIFO memory. The apparatus includes a signal processing circuit to repeatedly process the stored digital signal in the secondary storage. When detecting data, operation of the circuit is efficiently controlled by a change over detector parameters, in which characteristics for the detecting performance. Resultantly, data recovery processing speed is increased and reliability of data reproduced is improved.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: February 14, 2012
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Terumi Takashi, Seiichi Mita, Atsushi Saito
  • Patent number: 8089717
    Abstract: When the format control circuit detects bit synchronization information in a sector to be reproduced on a magnetic disk, the format control circuit activates a read gate signal for commanding to read out the sector from the magnetic disk. When symbol synchronization information on the magnetic disk is detected, a SYNC detection circuit produces a synchronization information detection signal. The format control circuit calculates an end position of the sector on the magnetic disk on the basis of the synchronization information detection signal to inactivate the read gate signal. The data correction circuit and the decoding circuit reproduce data and ECC in the sector read out from the magnetic disk during the period that the read gate signal is active on the basis of the synchronization information detection signal to produce the data and ECC to a data bus.
    Type: Grant
    Filed: August 15, 2000
    Date of Patent: January 3, 2012
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Terumi Takashi, Kazuhiko Satake
  • Patent number: 8085499
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: September 23, 2010
    Date of Patent: December 27, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Publication number: 20110205664
    Abstract: An information storing device and an information processing device having a memory for registering a plurality of working modes at recording/reproduction and a switching circuit for selecting one of the plurality of working modes, which select the optimum working mode automatically or by an instruction of an operator according to power supply capacity of a device of higher rank to effect recording/reproduction.
    Type: Application
    Filed: October 20, 2010
    Publication date: August 25, 2011
    Applicant: HITACHI GLOBAL STORAGE TECHNOLOGIES JAPAN, LTD.
    Inventors: Yuichi KOIZUMI, Hideaki AMANO, Katsuhiro TSUNETA, Koji KODAMA
  • Patent number: 7982999
    Abstract: An information storing device and an information processing device having a memory for registering a plurality of working modes at recording/reproduction and a switching circuit for selecting one of the plurality of working modes, which select the optimum working mode automatically or by an instruction of an operator according to power supply capacity of a device of higher rank to effect recording/reproduction.
    Type: Grant
    Filed: February 7, 2005
    Date of Patent: July 19, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yuichi Koizumi, Hideaki Amano, Katsuhiro Tsuneta, Koji Kodama
  • Patent number: 7903374
    Abstract: A magnetic recording and reading device includes a perpendicular magnetic recording medium, a perpendicular magnetic head having a recording head width having a heat-generating portion and a reading head, a fine adjustment portion, and a R/W-IC. The perpendicular magnetic head is configured to perform magnetic recording on the recording medium while locally heating the recording medium so as to enable a change of the coercive force of the recording medium during the recording after correcting of the position of the perpendicular magnetic head by the fine adjustment portion is completed, and to perform reading of the magnetic recording information with the aid of the reading head after correcting of the position of the perpendicular magnetic head by the fine adjustment portion is completed.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: March 8, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventor: Yoshihiro Shiroishi
  • Patent number: 7885039
    Abstract: A magnetic-head supporting mechanism includes a slider having a chamfered bleed portion, a mounting portion on which the slider is mounted, a flexible finger portion extending in a longitudinal direction and supporting the mounting portion, a load beam extending in the longitudinal direction that connects at an end to a positioning mechanism, and that applies a load to the slider, and a regulating member extending from the load beam in the longitudinal direction for preventing change of an attitude of the slider when an angular attitude of the slider exceeds a predetermined angle. The regulating member extends over and above the flexible finger portion and over and above the slider and has an end in the longitudinal direction at a position approximately equal to an end of the flexible finger portion in the longitudinal direction.
    Type: Grant
    Filed: November 5, 2008
    Date of Patent: February 8, 2011
    Assignee: Hitachi Global Storage Technologies Japan, LTd.
    Inventors: Mikio Tokuyama, Yukio Katou, Jyousei Shimizu, Yasuo Kojima, Hiroshi Nishida, Kouki Uefune
  • Patent number: 7865799
    Abstract: An efficient encoding method for error correction coding for recording/reproducing information in a high-density magnetic recording/reproduction apparatus. Based upon the principle of Turbo coding for random error-correction a practical encoding method is provided for preventing the propagation of code errors from being caused by the failure of the error correction due to burst signal errors existing on actual reproduced signal and recovering reliable code data from this. An information code sequence is divided in units of code block and the random error-correction coding is applied to an individual code block. Concatenated coding with hard-decision error-correction code for compensating a burst error is subsequently applied. This allows the encoding method to reduce the decoding time delay, or latency, in iterative decoding for the error-correction thereby achieving high-speed error correction.
    Type: Grant
    Filed: August 19, 2008
    Date of Patent: January 4, 2011
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventor: Hideki Sawaguchi
  • Patent number: 7839590
    Abstract: In a method of servo writing of a magnetic recording system and the magnetic recording system, the signal is recorded in a dummy area with a higher recording density than the burst signal. Also, the maximum bit length of the burst area is shortened as compared with the maximum bit length of the data area. A servo control method for perpendicular recording similar to that for longitudinal recording can be used to reduce the development cost. The anti-signal decay performance is also improved. Further, since the variations of the burst signal along the track width is suppressed, the positioning accuracy is improved. These effects combine to produce a reliable magnetic recording system of large capacity.
    Type: Grant
    Filed: September 9, 2008
    Date of Patent: November 23, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yasutaka Nishida, Takehiko Hamaguchi, Hideki Sawaguchi, Hisashi Takano
  • Patent number: 7817367
    Abstract: To effectively suppress a signal in a low frequency region in which the medium noise and the signal distortion are concentrated, and in order to effectively utilize a detected component of the reproduced signal in the low frequency region, a target of partial response equalization to the perpendicularly recorded/reproduced signal is set so that the low-frequency component around the direct current is suppressed to a regulated quantity for both the effective suppression and the effective utilization. Accordingly, a maximum-likelihood decoding process is carried out through the target of partial response equalization. Reliability of data detection is made higher and a signal-to-noise ratio is improved, so that the noise from the recording medium can be reduced more and it is possible to provide a high-density magnetic recording/reproducing apparatus.
    Type: Grant
    Filed: September 17, 2008
    Date of Patent: October 19, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Hideki Sawaguchi, Yasutaka Nishida, Hisashi Takano, Hiroyuki Tsuchinaga
  • Patent number: 7813079
    Abstract: Thin film perpendicular magnetic head with a narrow main pole capable of a high recording density in excess of 100 gigabits per square inch and generating a high magnetic recording field, while also being modified to suppress remanent magnetic fields occurring immediately after writing operation. A return path is provided for supplying a magnetic flux to the main pole, and an conductive coil for excitation of the main pole and return path. The main pole has a pole width of 200 nanometers or less, and a magnetic multilayer made up of a high saturation flux density layer and low saturation flux density layer. The low saturation flux density layer and the high saturation flux density suppress remanent magnetization and prevent erasing after writing by utilizing a closed magnetic domain structure in the pole.
    Type: Grant
    Filed: October 21, 2008
    Date of Patent: October 12, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiaki Kawato, Kazuhiro Nakamoto, Hiroyuki Hoshiya, Yasuyuki Okada, Masafumi Mochizuki
  • Patent number: 7782566
    Abstract: A magnetic recording and reading device includes a magnetic recording medium having at least one magnetic recording layer, a magnetic head enabling a data transfer rate of more than 50 MB/s and a recording density of more than 5 Gb/in2 on the magnetic recording medium, and a R/W-IC. The magnetic head includes a recording head and a reading head. The at least one magnetic recording layer contains (1) at least one metal element selected from a first group consisting of Co, Fe and Ni as a primary component, and (2) at least two elements selected from a second group consisting of Cr, Mo, W, V, Nb, Ta, Ti, Zr, Hf, Pd, Pt, Rh, Ir and Si.
    Type: Grant
    Filed: December 28, 2007
    Date of Patent: August 24, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventor: Yoshihiro Shiroishi
  • Patent number: 7783895
    Abstract: A controller of a recording device issues a secure command to a storage device, and then waits the time estimated necessary for the storage device to execute the secure command before issuing the next secure command. When a controller of the storage device is executing the previous command, it notifies the recording device of being in process. When the previous command has been completed normally, the controller moves to the next process. Information for estimating the execution time of the command is obtained from the storage device in advance.
    Type: Grant
    Filed: March 26, 2004
    Date of Patent: August 24, 2010
    Assignees: Sanyo Electric Co., Ltd., Sharp Corporation, Victor Company of Japan Limited, Pioneer Corporation, Fujitsu Limited, Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshihiro Hori, Yuichi Kanai, Ryoji Ohno, Takeo Ohishi, Kenichiro Tada, Tatsuya Hirai, Masafumi Tsuru, Takayuki Hasebe
  • Patent number: 7752461
    Abstract: A log region of a memory card includes a plurality of log entries and a plurality of administration information storage units. Each of the plurality of log entries includes a license ID region, a Ks2w region, a status region and a KPcmy region. The status region includes a ST1 region and a ST2 region to store the communication status. The license ID region stores a license ID. The Ks2w region stores a session key. The KPcmy region stores a class public encryption key of a memory card. The administration information storage unit stores the last record sequence number corresponding to the log entry storing history information of the latest communication.
    Type: Grant
    Filed: January 13, 2003
    Date of Patent: July 6, 2010
    Assignees: Sanyo Electric Co., Ltd., Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshihiro Hori, Tatsuya Hirai
  • Patent number: 7721346
    Abstract: A technology is provided to improve tamper resistance in encrypting data to be secured and inputting/outputting the data between a recording device and a host device. When the recording device issues an input/output command to a storage device to input/output data to be secured, the recording device attaches an ID to the command to identify to which cryptographic input/output processing the command belongs. Upon reception of a sequence command, the storage device receives the command if its ID has been allocated and the command is verified to have been issued in the correct sequence. The sequence ID is used to identify a process system while appropriately managing the steps of executing commands.
    Type: Grant
    Filed: March 26, 2004
    Date of Patent: May 18, 2010
    Assignees: Sanyo Electric Co., Ltd, Pioneer Corporation, Fujitsu Limited, Sharp Corporation, Hitachi Global Storage Technologies Japan, Ltd., Victor Company of Japan Limited, Phoenix Technologies K.K. of Tokyo
    Inventors: Yoshihiro Hori, Yuichi Kanai, Ryoji Ohno, Takeo Ohishi, Kenichiro Tada, Tatsuya Hirai, Masafumi Tsuru, Takayuki Hasebe
  • Patent number: 7667921
    Abstract: A suspension having a magnetic head assembly 1 mounted thereon is provided, wherein the magnetic head assembly comprises: a write head 1-2; a read head 1-1; and a resistive heating element 1-3 for controlling the flying heights of the magnetic heads, wherein the wires HTx and GTx for the resistive heating element is disposed such that they sandwich the wires RxX and RxY for the read head. The wires for the resistive heating element may be disposed between the wires for the write head and the wires for the read head. Furthermore, the waveform of the current or voltage to the resistive heating element has a time constant of 1 ?sec or more, the resistive heating element having wires disposed near the wires of the read head.
    Type: Grant
    Filed: April 4, 2008
    Date of Patent: February 23, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Naoki Satoh, Masayuki Kurita, Mikio Tokuyama, Juguo Xu
  • Patent number: 7643245
    Abstract: A magnetic disc unit includes a rotating disc type magnetic disc, a head for recording and reproducing data to and from the magnetic disc, and a head support mechanism for supporting the head. The magnetic disc unit includes a shroud surrounding an outer periphery of the magnetic disc other than at least at an inserting part of a carriage arm which is linked to the magnetic head support mechanism. A gap between an end face of the outer periphery of the magnetic disc and the shroud is set in a range not less than 0.1 mm but not greater than 0.4 mm.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: January 5, 2010
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Mikio Tokuyama, Hayato Shimizu, Satomitsu Imai, Shozo Saegusa, Masahiko Sega, Toshihisa Okazaki, Yuzo Yamaguchi
  • Patent number: 7625646
    Abstract: Disclosed are a perpendicular magnetic recording medium with lower medium noise, insusceptible to thermal fluctuation and high recording resolution and a method of manufacturing it. As the step of forming a metal layer at the time of forming a recording layer on a non-magnetic substrate via a plurality of underlayers and the step of forming an oxide layer with an average thickness of 0.2 nm or less are repeated, the crystal grains are magnetically isolated without disturbing the orientation of the crystal grain of the recording layer of the perpendicular magnetic recording medium or without degrading the magnetic characteristic of the crystal grain of the recording layer.
    Type: Grant
    Filed: February 15, 2006
    Date of Patent: December 1, 2009
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Yoshiyuki Hirayama, Ichiro Tamai, Takayuki Ichihara, Hiroyuki Nakagawa, Hiroaki Nemoto, Mineaki Kodama, Ikuko Takekuma