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：JP2000132933A

公开(公告)日：2000-05-12

申请号：JP30081298

申请日：1998-10-22

Applicant: IBM

Inventor： MATSUBARA NOBUYA ,  KAGAMI NAOYUKI ,  TOKIZONO AKIRA

IPC: G11B5/00 ,  G11B5/012 ,  G11B5/31 ,  G11B5/455 ,  G11B5/596 ,  G11B21/10 ,  G11B27/36

Abstract: PROBLEM TO BE SOLVED: To provide a data writing control method of a head which can prevent off-track writing, accidental writing of data into an off track during the writing of data with the head and a memory device utilizing the same. SOLUTION: An amplitude value of an output signal of a magnetic head 6 in a servo region is preferably or constantly monitored. In the preferable embodiment, the amplitude value of the output signal is obtained from a value as given when a voltage of a capacitor 15 used at a VGA(Variable Gain Control) 13 in an AGC(Automatic Gain Control) 12 of a channel unit 11 composing one circuit of a hard disc drive is measured and undergoes an A/D conversion. Then, it is judged whether the obtained amplitude value is abnormal or nor. When it is abnormal, the writing of data to be stored by the magnetic head 6 is stopped. In the ideal example, the abnormality is determined when the amplitude value of the output signal of the magnetic head is smaller than the amplitude value previously determined of the output signal in the normal magnetic head. The data writing control method of the head thus obtained is utilized for a memory device.

公开(公告)号：JP2002260355A

公开(公告)日：2002-09-13

申请号：JP2001052643

申请日：2001-02-27

Applicant: IBM

Inventor： HATTORI RYOHEITA ,  MATSUBARA NOBUYA ,  KOKUBO TETSUYA ,  UMEMURA KAORU ,  KAGAMI NAOYUKI

IPC: G11B21/10 ,  G11B19/04 ,  G11B20/18 ,  G11B27/36 ,  G11B33/10

Abstract: PROBLEM TO BE SOLVED: To improve the reliability of a burst pattern inspection in a hard disk drive. SOLUTION: The writing test of test pattern data on a track boundary is added besides the writing of a test pattern in a SAT test at the track center conventionally performed and the inspection of burst patterns (A, B patterns) by the writing test at that time. Thereby, a highly sensitive inspection of C and D burst patterns sensitive to a PES signal can be conducted on the track boundary.

公开(公告)号：JPH1145516A

公开(公告)日：1999-02-16

申请号：JP20015897

申请日：1997-07-25

Applicant: IBM

Inventor： HATANO AKIRA ,  KAGAMI NAOYUKI ,  MATSUBARA NOBUYA

IPC: G11B5/09 ,  G06F11/267 ,  G11B20/12 ,  G11B20/18

Abstract: PROBLEM TO BE SOLVED: To drastically reduce unnecessary flags and to reduce defective disks by preventing errors to be generated at random from being flagged. SOLUTION: A cyclic redundant check CRC is performed on read data by a CRC circuit 20, and a data error is detected by an ECC circuit 21. At this time, a surface analyzation test SAT is executed by a calculator 16 in such an algorithm that when error generation positions in the same sector are apart from one another by more than a prescribed distance, no flagging is carried out. In other words, a data is read out of a target data area, and an error position is detected by the ECC circuit 21 to check distances of the previous and present error portions respectively, and if there distances are closer values than the prescribed distance perceptively, checking the distance is performed a prescribed number of times, and if the closer state is more than prescribed criteria, flagging is performed. Consequently, flags on errors caused at random by noise are drastically reduced, and errors required for flags are certainly flagged.

公开(公告)号：JPH1173757A

公开(公告)日：1999-03-16

申请号：JP22901997

申请日：1997-08-26

Applicant: IBM

Inventor： FUKUHISA RYOJI ,  MATSUBARA NOBUYA ,  HIRASHITA SHOICHI

IPC: G11B21/08 ,  G11B19/02 ,  G11B27/10

Abstract: PROBLEM TO BE SOLVED: To shorten the time for processing at every command by executing plural commands containing a first command and a second command sent from a host computer with once command in a device. SOLUTION: A CPU 19 judges whether or not a final address of a first sector address specified by the first command is adjacent with a top address of a second sector address specified by the second address when plural commands are sent from the host computer 22. When not adjacent, a not specified address existing between the first final address and the second top address is specified, and the commands accessing the first, second sector addresses are imparted to the specified address to be imparted to an HDC 17. An access means accesses the sector specified by the second command while skipping the not specified address after it accesses the sector specified by the first command.

公开(公告)号：JPH1116305A

公开(公告)日：1999-01-22

申请号：JP16413097

申请日：1997-06-20

Applicant: IBM

Inventor： MATSUBARA NOBUYA ,  SAI FUMINORI ,  NAKAGAWA YUZO

IPC: G11B21/10 ,  G11B5/012 ,  G11B5/09 ,  G11B7/00

Abstract: PROBLEM TO BE SOLVED: To provide a disk drive device which realizes reduction in numerous control signals and cost and easily realizes countermeasure for noise. SOLUTION: An HDD(hard-disk drive) 100 has an HDC(hard-disk controller)/MPU 101 which controls data readout/write operation of a head, a preamplifier 102 which amplifies data from the magnetic head and a channel module 202 which is controlled by the HDC/MPU 101 to convert digital data into a write data and convert an analog signal obtained from the preamplifier 102 into a digital signal. In this case, a signal line for controlling the channel module 202 is replaced with control information. The control information is transmitted via NRZ bus which transmits data signals for readout/writing. The channel module 202 is configured so as to perform control based on the transmitted control information.

公开(公告)号：SG77183A1

公开(公告)日：2000-12-19

申请号：SG1998001426

申请日：1998-06-16

Applicant: IBM

Inventor： MATSUBARA NOBUYA ,  SAI FUMINORI ,  NAKAGAWA YUZO

IPC: G11B5/012 ,  G11B5/09 ,  G11B7/00 ,  G11B21/10 ,  G11B21/12 ,  G11B20/10 ,  G11B5/035

Abstract: A hard disk drive (HDD) having a control unit that reduces the number of control signals required to control the operation of the channel and amplifier. The HDD includes a control unit for controlling reading or writing data from or to a magnetic head, a preamplifier for amplifying the data from the magnetic head, and a channel module which is controlled by the control unit. The channel module converts digital data signals to data write signals and also converts analog signals from the preamplifier to digital signals. Control information is transmitted to the channel module over the data bus which is used to transmit or receive data read/write signals. The channel module performs control in response to transmitted control information.