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

IPC: G11B5/012 ,  G11B5/09 ,  G11B20/10

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.

公开(公告)号：JP2000173198A

公开(公告)日：2000-06-23

申请号：JP33615298

申请日：1998-11-26

Applicant: IBM

Inventor： KIMURA JUNICHI ,  HASHIMOTO SATOSHI ,  KISAKA MASASHI

IPC: G11B20/10 ,  G11B5/00 ,  G11B5/012 ,  G11B20/12 ,  G11B20/18 ,  G11B27/36

Abstract: PROBLEM TO BE SOLVED: To easily detect the error caused by thermal asperity by controlling a recording and reproducing means and executing an error recovery processing without conducting a compensation by a compensating means when an error is detected in a recording and reproducing operation. SOLUTION: An arm electronic circuit (AE) 3 is provided with a signal adaptive filter 3a. The SAF 3a reduces the adverse effect caused by thermal asperity (TA) through eliminating the low frequency components of the reproduced output of a head 2, for example. Note that the operation of the SAF 3a is made controllable from an MPU 7, the SAF 3a is invalidated while executing an ERP, and TA is positively detected. By adding a step which invalidates the operation of the SAF3a that compensates for the reproduced output of the head 2 during an error recovery processing, thermal asperity is easily detected and the data sector, in which TA is generated, is surely registered as a defective sector.

公开(公告)号：JP2000123492A

公开(公告)日：2000-04-28

申请号：JP29095798

申请日：1998-10-13

Applicant: IBM

Inventor： OSAWA TOYOZO ,  KOBAYASHI KEIJI ,  KOWA TSUGUAKI ,  HASHIMOTO SATOSHI

IPC: G11B20/12 ,  G11B5/012 ,  G11B5/09 ,  G11B19/02

Abstract: PROBLEM TO BE SOLVED: To provide a disk type recording medium, a disk drive device, and the like that yield can be improved, complexness of control can be reduced, and reduction of performance can be suppressed. SOLUTION: Recording line density of a recording plane (e.g. 1c) of which a software error rate(SER) is bad is reduced, and recording line density of recording planes (e.g. 1a, 1b, 1d, 1e, 1f) of which SER is not so bad is increased. A control section 4e or a control section 5a changes a table in accordance with recording line density of each recording plane 1a-1f at the time of recording and reproducing, and changes recording and reproducing characteristics.