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公开(公告)号：JPH08263815A
公开(公告)日：1996-10-11
申请号：JP23191294
申请日：1994-09-27
Applicant: IBM
Inventor： OGASAWARA KENJI , YANAGISAWA HIROSHI , KURACHI KOJI
Abstract: PURPOSE: To accurately position write and read magnetic heads by forming plural data tracks in a prescribed direction and recording 1st to 4th burst patterns. CONSTITUTION: Plural burst pattern recording areas 50 are formed radially along a radial direction of a disk 18 and remaining areas are used for a data track area 52. A test pattern is formed on the areas 50 by recording data in a prescribed pattern. The test patterns are made up of four burst pattern strings A-D formed radially on the disk 18. In each of the data recording areas for each burst pattern string, an interval between the adjacent areas along the radial direction of the disk 18 is selected equal to a pitch P of the data track areas 54.
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公开(公告)号：JPH11191201A
公开(公告)日：1999-07-13
申请号：JP35689697
申请日：1997-12-25
Applicant: IBM
Inventor： SUZUKI HIROMASA , KURACHI KOJI , SUDA KATSUMI , ASANO HIDEO , OKADA KENJI , TAKASE MAKOTO , KIHASHI AKIRA , NISHINOMIYA HIROMI , MATSUI TAKAO , ENDO TATSUYA , KUROKI KENJI
Abstract: PROBLEM TO BE SOLVED: To improve the performance of an information recording/reproducing device using a GMR(giant magnet resistance) sensor. SOLUTION: This method aims at the restoration of an operating error generated in an information recording/reproducing device including a storage medium, a head using a GMR sensor, an actuator arm for mounting the head and locating the head on a prescribed position on the front surface of the storage medium and a control part for controlling the operation of the actuator arm and read/write operation. At this time, it comprises a step for executing a first error restoring procedure 103, a step for executing a first GMR evaluating procedure 109 for evaluating the performance of the GMR sensor when the operating error is not restored in the first error restoring procedure and a step 117 for impressing a reset pulse to the GMR sensor in accordance with the first GMR evaluating procedure.
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3.发明专利
公开(公告)号：JPH08129707A
公开(公告)日：1996-05-21
申请号：JP26745394
申请日：1994-10-31
Applicant: IBM
Inventor： KURACHI KOJI , HASHIMOTO SATOSHI , YANAGISAWA HIROSHI
Abstract: PURPOSE: To correct the position of a peak located at a predetermined position of a read-out signal while suppressing deterioration in S/N ratio. CONSTITUTION: A comparator 36 determines the shifting direction of a peak located in the center with respect to the original position thereof from threshold levels corresponding to the magnitude of three continuous peaks of an RBS detected by a circuit 26 according to the relationship of magnitude between |AMP-1 -AMP0 | and |AMP0 -AMP1 | assuming the magnitude of three peaks are AMP-1 , AMP0 and AMP1 and outputs a pulse indicative of the shifting direction to an FIFO 38. A delay circuit 44 outputs a plurality of pulses being shifted by an amount corresponding to the threshold level based on the input timing of a PDS. An MUX 40 selects the output pulse from the delay circuit 44 based on the pulse indicative of the shifting direction from the FIFO 38 and |AMP-1 -AMP1 | detected by an amplitude difference detection circuit 100.
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4.发明专利
公开(公告)号：JPH08279262A
公开(公告)日：1996-10-22
申请号：JP7514995
申请日：1995-03-31
Applicant: IBM
Inventor： SUZUKI HIROMASA , OGASAWARA KENJI , KAWAMURA MASAHARU , KURACHI KOJI
Abstract: PURPOSE: To increase reliability in a servo without decreasing a data area, etc., by a method wherein a servo compensation signal is written using a write retrieval area. CONSTITUTION: A plurality of servo areas 50 are radially formed along a radius direction of a disk in a data area 52 on each recording face of the disk, a gray code (a cyclic binary-code) showing an address of a data track is recorded therein corresponding to the data track, and further a burst pattern serving as a signal for positioning for a track of a head is recorded. The track is formed at a specific pitch P in the data track area 52, and a plurality of data are recorded in the track accompanied by an ID being each identifying data. A servo compensation signal area 53 is formed in a position interposed between the data area 52 and the servo area 50. This compensates a servo signal for the servo area and enables an error retrieval when a read error etc., generates in the servo area.
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公开(公告)号：JPH0737216A
公开(公告)日：1995-02-07
申请号：JP15500793
申请日：1993-06-25
Applicant: IBM
Inventor： KIGAMI YUJI , MATSUI TAKAO , KURACHI KOJI , OSAWA TOYOZO
Abstract: PURPOSE: To improve a reading error rate on identification(ID) information in a sector servo type magnetic disk device provided with a head having a separated reading element and writing element. CONSTITUTION: One pair of ID fields 21a and 21b for recording ID information are set in each sector of each track of the magnetic disk. This one pair of ID fields are mutually separated in the direction along the track and radially deviated each other by the distance equivalent to the radial direction offset between the reading element 24 and writing element 23 related to the track. The magnetic head is positioned so as to read ID information in the ID field 21b with the reading element 23 at the time of a data writing operation on an optional track. The head is positioned so as to read ID information in the ID field 21a with the reading element 23 at the time of a data reading operation on the track.
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Patent Agency Ranking
公开(公告)号：JPH03122802A
公开(公告)日：1991-05-24
申请号：JP25897089
申请日：1989-10-05
Applicant: IBM
Inventor： OGASAWARA KENJI , KURACHI KOJI , TOBARI ATSUSHI
Abstract: PURPOSE: To suppress the distortion of a reading signal by generating a DC bias magnetic field for a magnetic material when the reading signal is read. CONSTITUTION: When a reading signal is read from a reading/writing coil 4, a direct current having a specified value is allowed to flow through a DC bias magnetic field coil 5 to generate DC bias magnetic fields in magnetic materials 1 and 2. At this time, a magneto striation effect is induced between the magnetic materials 1 and 2 putting a gap part 3 between from both sides. Then, the gap part 3 is compressed, and the tensile stress of the gap part 3 caused by a thermal expansion difference between the gap part 3 and the magnetic materials 1 and 2 is canceled. Thus, the reverse magnetostriction effect is not generated in the magnetic materials 1 and 2, and anisotropy is not induced. Thus, high-density recording is performed by suppressing the distortion of the reading signal.
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公开(公告)号：JPH07211000A
公开(公告)日：1995-08-11
申请号：JP31878093
申请日：1993-12-17
Applicant: IBM
Inventor： KIGAMI YUJI , YOKOE YUJI , NUMATA TSUTOMU , NAKAMURA TAKASHI , OGASAWARA KENJI , KURACHI KOJI , MATSUI TAKAO , OKADA MAYUMI
Abstract: PURPOSE: To refer to information on constitution or the like for respective sectors and to increase information quantity by permitting a hard disk controller to calculate an absolute block address to calculate a physical position in a specified zone and executing a seek operation based on the physical position. CONSTITUTION: The hard disk controller HDC 30 refers to a defect list D-LST and calculates the absolute block address ABA by all the sectors, which corresponds to a designated logic block address LBA. When a host computer requests the reading of the sectors from #L to #M in the address LBA, the absolute block address ABA is calculated to be #N. When the belonging zone Zn is set to be #Z, the min address ABA is to be MIN-ABBA(#Z) and a min cylinder is MIN-CYL(#Z), the address ABA is shown by an expression. Then, #ZN is set to be the serial numbers of the sectors. The head is switched and the seek operation is executed based on the physical position which is thus calculated.
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公开(公告)号：GB2279491B
公开(公告)日：1997-02-05
申请号：GB9411354
申请日：1994-06-07
Applicant: IBM
Inventor： KURACHI KOJI , OHSAWA TOYOMI , MATSUI TAKAO , KIGAMI YUJI
Abstract: The object is to improve the read error rate for identification (ID) information In a sector servo type magnetic disk drive with a head comprising separate read and write elements. A pair of ID fields 21a and 21b are set up in each sector In each track of a magnetic disk for recording ID Information. The pair of ID fields are separated from each other along the track and radially displaced with respect to each other by a distance equal to an offset between the read element 24 and the write element 23 associated with the track. In a data write operation for a trace the magnetic head is positioned so as to read the ID information in the ID field 21b with the read element 23. In a read operation for the track, the head is positioned so as to read the ID information in the ID field 21a with the read element 23.
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公开(公告)号：DE69018917T2
公开(公告)日：1995-11-23
申请号：DE69018917
申请日：1990-09-28
Applicant: IBM
Inventor： OGASAWARA KENJI , KURACHI KOJI , TOBARI ATUSHI
Abstract: A magnetic data storage apparatus employs a magnetic head which has a non-magnetic gap member (3) disposed in a magnetic body (1, 2) with positive magnetostriction constant. During reading of data from a recording medium by a coil (4) wound around the magnetic body, a dc bias magnetic field is caused to be generated in the magnetic body. This field causes a magnetostriction effect in the magnetic body which compresses the gap member thereby cancelling the tensile stress generated by the expansion rate difference between gap member and magnetic body.
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公开(公告)号：GB2279491A
公开(公告)日：1995-01-04
申请号：GB9411354
申请日：1994-06-07
Applicant: IBM
Inventor： KURACHI KOJI , OHSAWA TOYOMI , MATSUI TAKAO , KIGAMI YUJI
Abstract: The object is to improve the read error rate for identification (ID) information In a sector servo type magnetic disk drive with a head comprising separate read and write elements. A pair of ID fields 21a and 21b are set up in each sector In each track of a magnetic disk for recording ID Information. The pair of ID fields are separated from each other along the track and radially displaced with respect to each other by a distance equal to an offset between the read element 24 and the write element 23 associated with the track. In a data write operation for a trace the magnetic head is positioned so as to read the ID information in the ID field 21b with the read element 23. In a read operation for the track, the head is positioned so as to read the ID information in the ID field 21a with the read element 23.
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