公开(公告)号：JPH09167457A

公开(公告)日：1997-06-24

申请号：JP33025695

申请日：1995-12-19

Applicant: IBM

Inventor： KITAZAKI NOBUYUKI ,  OGASAWARA KENJI ,  MASUDA YOSHIMI ,  NAKAMURA TAKASHI ,  YANAGISAWA HIROSHI

IPC: G11B21/04 ,  G11B19/02 ,  G11B21/08 ,  G11B21/10

Abstract: PROBLEM TO BE SOLVED: To improve the performance by forming a data track in a spiral state with the use of the servo area arranged in the peripheral direction of a disk at every specified space and unnecessitating the seek operation for the movement between tracks in the reading/writing operation for continued data. SOLUTION: The constitution is made in such a manner that the target value of a PES(position error signal) obtained from servo signals which are buried on the track with the specified spaces, is successively changed for realizing the spiral track by reading the PES which is the conventional servo information. In the case of the disk device performing the positional control with the PES obtained from each servo area in the disk which is provided with the servo area of 60 pieces per one round of the disk, when the values available for the PES as the information on each position in the width direction of one track are taken as 256 kinds, the positional control of the head is executed by the value set by succesively shifting the target value of PES for every 256/60 track position in each of 60 servo positions. By such a positional control, the head is moved in accordance with the target PES values different for every servo area, thereby, the spiral track is followed up.

公开(公告)号：JPH0945023A

公开(公告)日：1997-02-14

申请号：JP19010995

申请日：1995-07-26

Applicant: IBM

Inventor： OGASAWARA KENJI ,  NAKAMURA TAKASHI ,  MATSUBARA NOBUYA ,  NAKAGAWA YUZO ,  KIGAMI YUJI ,  UCHIIKE HIROSHI ,  NUMATA TSUTOMU

IPC: G11B21/10 ,  G11B5/55 ,  G11B5/596 ,  G11B21/08

Abstract: PROBLEM TO BE SOLVED: To prevent servo information from being reproduced of error and to form correct servo information, by providing a plurality of bit patterns which are not prevent principally in other servo areas than a servo start mark SSM. SOLUTION: A cylindrical support 16 is set to a shaft 12, with having one or more data-recording discs 18A, 18B loaded at an outer peripheral face thereof. A data area 52 is formed in each recording face of the discs 18A, 18B. Servo areas 50 are radially formed in the data area. A start position of the servo area is indicated by a servo start mark SSM. A plurality of bit patterns in the signal SSM are constituted so as not to be read in other servo areas, i.e., a gray code area, a sector area and a position error signal PES area. Therefore, the SSM signal is never read out in the other servo areas, and reading errors and prevented.

公开(公告)号：JPH08106619A

公开(公告)日：1996-04-23

申请号：JP23371894

申请日：1994-09-28

Applicant: IBM

Inventor： OGASAWARA KENJI ,  SUGANUMA SHIGEMI ,  SATO KENICHIRO

IPC: G11B5/39 ,  G11B5/56 ,  G11B5/596 ,  G11B21/10

Abstract: PURPOSE: To control the position of an MR head so as to place at a predetermined position by previously storing the corresponding relation between distance information corresponding to the deviation of the head from a reference position and the information reproduced from an information recording disk in response to the deviation. CONSTITUTION: An HDC 30 has a controller body 40 of a microcomputer. The body 40 has a memory 42 for storing a table for positioning a magnetic head to decide a microjog amount in the case of recording and reproducing processes of a disk. The body 40 is connected to a driver 28 having a D-A converter 28a, amplifier 28b, and voice coil motor VCM 28c. Accordingly, the digital signal output from the body 40 is converted into an analog signal by the D-A 28a, amplified by predetermined magnification by the amplifier 28b, and then supplied to the VCM 28c. The VCM 28c rotates at a predetermined angle responsive to the supplied signal, and turns access arms 22A to 22D at a predetermined angle.

公开(公告)号：JPH07320247A

公开(公告)日：1995-12-08

申请号：JP10876294

申请日：1994-05-23

Applicant: IBM

Inventor： MATSUI TAKAO ,  OGASAWARA KENJI

IPC: G11B5/39 ,  G11B5/012 ,  G11B5/48 ,  G11B5/55 ,  G11B5/56 ,  G11B5/596 ,  G11B19/04

Abstract: PURPOSE: To inhibit the quantity of an offtrack of a reproducing element within a range moving in a magnetic head by positioning the reproducing element of the magnetic head so as to be equalized from the center of a track. CONSTITUTION: The sorting of processing by a magnetic head 20A to a disk 18A is set first. A positioning method refers to a map first. A skew angle is read. The quantity of a micro-Jog in either processing of set skew angle and data recording processing, data reproducing processing and format processing as objects is set. An access arm 22A is driven in response to the quantity of the micro-jog set. Accordingly, since the micro-jog is distribute within a linear range from the quantity of an offtrack at a time when the offtrack from a track center to one side is conducted by a reproducing element to the quantity of another offtrack and an MR head is positioned, the characteristics of the reproducing element having an MR effect can be utilized maximally and effectively.

公开(公告)号：JP2001195851A

公开(公告)日：2001-07-19

申请号：JP2000007318

申请日：2000-01-17

Applicant: IBM

Inventor： KITAZAKI NOBUYUKI ,  OGASAWARA KENJI ,  YONEDA ISAO ,  OZAWA YUTAKA

IPC: G11B21/08 ,  G11B5/596 ,  G11B19/28 ,  G11B20/14 ,  G11B21/10 ,  G11B19/247

Abstract: PROBLEM TO BE SOLVED: To surely and stably detect servo information even if a disk shift occurs and the time intervals between servo sectors fluctuate. SOLUTION: The time intervals TS (i) after the servo sector in a servo region SF (i) passes under a read/write head before the servo sector in the next servo region SF (i+1) passes under the read/write head are calculated (step S6) in accordance with the internal variable value proportional to the displacement Δr(i) in the disk diametral direction of the servo region SF (i) calculated from already detected servo information and the time intervals to detect the servo information are regulated in accordance with the time intervals TS (i) (steps S7 and S4).

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

IPC: G11B5/55 ,  G11B5/596 ,  G11B20/12 ,  G11B21/08 ,  G11B21/10

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.

公开(公告)号：JPH08195046A

公开(公告)日：1996-07-30

申请号：JP430395

申请日：1995-01-13

Applicant: IBM

Inventor： OGASAWARA KENJI ,  YOKOE YUJI ,  NAKAMURA TAKASHI ,  YONEDA ISAO ,  KURISU CHIIRUN RIN

IPC: G11B21/10 ,  G06F3/06 ,  G11B19/02 ,  G11B19/04

Abstract: PURPOSE: To improve the reliability of data even when reading failure due to aging physical damage occurs. CONSTITUTION: When reading failure occurs, reading condition is altered to correcting reading condition (124 to 136) corresponding to reading failure dealing stage (120, 122). Data is again read from the disk according to the altered correcting reading condition (138), and when reading failure occurs (140), reading failure dealing stage is increased (142), and it is repeatedly executed until the reading failure dealing stage exceeds a predetermined stage (144). When a predetermined stage is exceeded, a hard error is output (146). When the data can be read again from the disk (140, 148), information transferring process (reassigning) is conducted (150) the data of the residual sector is read (152).

公开(公告)号：JPH0817153A

公开(公告)日：1996-01-19

申请号：JP15019494

申请日：1994-06-30

Applicant: IBM

Inventor： SUGAWARA TAKASHI ,  OGASAWARA KENJI ,  SATO KENICHIRO

IPC: G11B21/10 ,  G11B5/596

Abstract: PURPOSE: To contact a stable follow of the head in any area in the tracks. CONSTITUTION: A target PES(phase error signal) value input from a controller body 61 and a value corresponding to the displacement of the current magnetic head 58A from the PES value calculating means 56 are combined with a combining means 62, the predetermined coefficient K1 is given (multiplied) to this deviation by means of a coefficient giving means and a variable coefficient Ka is given by means of a variable coefficient giving means 47. The coefficient Ka is variably set to the variable coefficient giving means 47 depending on the value input from a table 48. The table 48 previously stores the corresponding relationship between the target PES value and the coefficient Ka as the feedback constant to the relevant PES value so that when change of PES value is large, the coefficient Ka becomes small and when PES value is small, the coefficient Ka becomes large. The variable coefficient giving means 47 outputs the value given the coefficient Ka depending on the value from the table 48 to a driver 46.

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

IPC: G11B5/02 ,  G11B5/09 ,  G11B5/245

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.

公开(公告)号：JP2002269938A

公开(公告)日：2002-09-20

申请号：JP2001055997

申请日：2001-02-28

Applicant: IBM

Inventor： KITAZAKI NOBUYUKI ,  OGASAWARA KENJI ,  SHIMIZU MASAHIRO

IPC: G11B21/08 ,  G11B5/55 ,  G11B21/10

Abstract: PROBLEM TO BE SOLVED: To enhance a servo tracking performance in a low frequency region without losing the stability of seek operations. SOLUTION: The position control system of the magnetic head is provided with two integrators; a 1st integrator 43 and a 2nd integrator 45. A gain K3' of the 2nd integrator 45 is set higher than a gain K3 of the 1st integrator 43. The 1st integrator 43 play a role of canceling a bias force acted on the magnetic head and the 2nd integrator 45 play a role of improving the servo tracking characteristic in the low frequency region.