Magnetic disk apparatus and data recording method

Abstract

A magnetic disk apparatus of one of the embodiments stores read position dependency information on read signal quality of a data region at a first track and measures the read signal quality at a predetermined radial position in a second data region of a second track different from the first track. A positioning error of the second data region is determined based on the read position dependency information and the read signal quality at the predetermined radial position. Data is recorded in a recording target data region in a singled recording so as to prevent data written in the second data region from being overwritten by data in a recording target data region adjacent to the second data region by using the determined positioning error.

What is claimed is: 
     
         1 . A magnetic disk apparatus, comprising:
 a magnetic disk in which a plurality of tracks are defined, each of the tracks alternately comprising a plurality of data regions and servo regions including burst information for detecting a positioning error;   a magnetic head writing and reading data for the magnetic disk; and   a processor,   wherein the processor is configured:   to measure read signal quality at a plurality of positions shifted from an average radial position of a recorded first data region of a first track to a radial direction of the magnetic disk, and to store read position dependency information obtained by shifting the measurement result by a first predetermined distance in the radial direction;   to measure read signal quality at a predetermined radial position remote by a second predetermined distance in the radial direction, from an average radial position of a recorded second data region of a second track different from the first track;   to determine a positioning error of the second data region, based on the stored read position dependency information and read signal quality at the predetermined radial position of the second data region; and   to record data in a recording target data region by using the magnetic head in a singled recording, to prevent data written in the second data region by using the determined positioning error from being overwritten by data in a recording target data region adjacent to the second data region.   
     
     
         2 . The apparatus of  claim 1 , wherein
 the processor   if data recording is executed in a data region of a predetermined track, reads servo regions of the predetermined track by the magnetic head, and detects a positioning error indicating displacement from a target recording position of the predetermined track, for each of the servo regions,   shifts the read signal quality for a plurality of read positions in the first data region, by a positioning error of servo region adjacent to the first data region, and obtains the read position dependency information, and   determines a distance between the predetermined radial position and a shift position in the read position dependency information at which the read signal quality at the predetermined radial position in the second data region is obtained, as a positioning error of the second data region.   
     
     
         3 . The apparatus of  claim 2 , wherein the processor obtains the read position dependency information in each of the plurality of data regions in a track in which the positioning error is already measured and stored, and stores an average value of the plurality of the read position dependency information obtained, as read position dependency information of the track. 
     
     
         4 . A magnetic disk apparatus, comprising:
 a magnetic disk in which a plurality of tracks are defined, each of the tracks alternately comprising a plurality of data regions and servo regions including burst information for detecting a positioning error;   a magnetic head writing and reading data for the magnetic disk; and   a processor,   wherein the processor is configured:   to read, at data recording in a data region of a predetermined track, servo regions of the predetermined track by the magnetic head, and to detect a positioning error indicating displacement from a target write position of the predetermined track, for each of the servo regions;   if data recording to a first track group on the magnetic disk is interrupted and data recording to a second track group is executed, to record a positioning error of a track where the data recording is last executed in the first track group, in a region on the magnetic disk; and   if the data recording to the first track group is restarted, to reproduce the positioning error recorded in the region on the magnetic disk, and to record data subsequent to a portion where the data recording is interrupted, by using the magnetic head, in a singled recording, to prevent the data recorded in the first track group from being overwritten by using the reproduced positioning error.   
     
     
         5 . The apparatus of  claim 4 , wherein
 the processor   records the positioning error of the track where the data recording is last executed, in a region after a recording interruption portion of the track where the data recording is last executed, and   if the data recording to the first track group is restarted, reproduces the recorded positioning error of the recorded track, and restarts data recording from a track subsequent to the track where the data recording is last executed by using the reproduced positioning error.   
     
     
         6 . The apparatus of  claim 4 , wherein
 the processor   records the positioning error for a distance of a track where the data recording is last executed, in a region after a recording interruption portion of the track where the data recording is last executed, and   if the data recording to the first track group is restarted, reproduces the recorded positioning error for a distance of a track, and restarts data recording from the region after the recording interruption portion of the track where the data recording is last executed by using the reproduced positioning error.   
     
     
         7 . The apparatus of  claim 4 , wherein
 the processor   records the positioning error of the track where the data recording is last executed, in a track subsequent to the track where the data recording is last executed, and   if the data recording to the first track group is restarted, reproduces the recorded positioning error of the track, and restarts data recording from the track subsequent to the track where the data recording is last executed by using the reproduced positioning error.   
     
     
         8 . A data recording method in a magnetic disk apparatus comprising: a magnetic disk in which a plurality of tracks are defined, each of the tracks alternately comprising a plurality of data regions and servo regions including burst information for detecting a positioning error; and a magnetic head writing and reading data for the magnetic disk;
 the method comprising:   measuring read signal quality at a plurality of positions shifted from an average radial position of a recorded first data region of a first track to a radial direction of the magnetic disk, and storing read position dependency information obtained by shifting the measurement result by a first predetermined distance in the radial direction;   measuring read signal quality at a predetermined radial position remote by a second predetermined distance in the radial direction, from an average radial position of a recorded second data region of a second track different from the first track;   determining a positioning error of the second data region, based on the stored read position dependency information and read signal quality at the predetermined radial position of the second data region; and   recording data in a recording target data region by using the magnetic head in a singled recording, to prevent data written in the second data region by using the determined positioning error from being overwritten by data in a recording target data region adjacent to the second data region.   
     
     
         9 . The method of  claim 8 , further comprising:
 if data recording is executed in a data region of a predetermined track, reading servo regions of the predetermined track by the magnetic head, and detecting a positioning error indicating displacement from a target record position of the predetermined track, for each of the servo regions;   shifting the read signal quality for a plurality of read positions in the first data region, by a positioning error of servo region adjacent to the first data region, and obtaining the read position dependency information; and   determining a distance between the predetermined radial position and a shift position in the read position dependency information at which the read signal quality at the predetermined radial position in the second data region is obtained, as a positioning error of the second data region.   
     
     
         10 . The method of  claim 9 , further comprising obtaining the read position dependency information in each of the plurality of data regions in a track in which the positioning error is already measured and stored, and storing an average value of the plurality of the read position dependency information obtained, as read position dependency information of the track. 
     
     
         11 . A data recording method in an magnetic disk apparatus comprising: a magnetic disk in which a plurality of tracks are defined, each of the tracks alternately comprising a plurality of data regions and servo regions including burst information for detecting a positioning error; and a magnetic head writing and reading data for the magnetic disk;
 the method comprising:   reading, at data recording in a data region of a predetermined track, servo regions of the predetermined track by the magnetic head, and detecting a positioning error indicating displacement from a target write position of the predetermined track, for each of the servo regions;   if data recording to a first track group on the magnetic disk is interrupted and data recording to a second track group is executed, recording a positioning error of a track where the data recording is last executed in the first track group, in a region on the magnetic disk; and   if the data recording to the first track group is restarted, reproducing the positioning error recorded in the region on the magnetic disk, and recording data subsequent to a portion where the data recording is interrupted, by using the magnetic head, in a singled recording, to prevent the data recorded in the first track group from being overwritten by using the reproduced positioning error.   
     
     
         12 . The method of  claim 11 , further comprising:
 recording the positioning error of the track where the data recording is last executed, in a region after a recording interruption portion of the track where the data recording is last executed; and   if the data recording to the first track group is restarted, reproducing the recorded positioning error of the recorded track, and restarting data recording from a track subsequent to the track where the data recording is last executed by using the reproduced positioning error.   
     
     
         13 . The method of  claim 11 , further comprising:
 recording the positioning error for a distance of a track where the data recording is last executed, in a region immediately after a recording interruption portion of the track where the data recording is last executed, and   if the data recording to the first track group is restarted, reproducing the recorded positioning error for a distance of a track, and restarting data recording from the region immediately after the recording interruption portion of the track where the data recording is last executed by using the reproduced positioning error.   
     
     
         14 . The method of  claim 11 , further comprising:
 recording the positioning error of the track where the data recording is last executed, in a track subsequent to the track where the data recording is last executed, and   if the data recording to the first track group is restarted, reproducing the recorded positioning error of the track, and restarting data recording from the track subsequent to the track where the data recording is last executed by using the reproduced positioning error.