Data storage apparatus, read data processor, and read data processing method

• US 6,981,205 B2
• Filed: 10/23/2002
• Issued: 12/27/2005
• Est. Priority Date: 10/23/2001
• Status: Active Grant

• Current Assignee: Lenovo PC International Limited (Lenovo Group Ltd.)
• Original Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Inventors: Kobayashi, Shunsuke, Shimono, Emi, Kuroda, Takashi, Katoh, Katsuhiko, Ueda, Tetsuo, Nakagawa, Yuzo, Tamura, Tetsuya, Sai, Fuminori, Fukushima, Yukio
• Primary Examiner(s): Ton, David
• Application Number:
  US10/279,305
• Publication Number:
  US 20030112669A1
• Time in Patent Office: 1,161 Days
• Field of Search: 714/769, 714/797, 714/763, 714/764, 360/53, 360/47.34, 360/13.05
• US Class Current: 714/797
• CPC Class Codes: G11B 20/1809 by interleaving

Abstract

To improve the probability of error correction, thereby generating correct read data. Data is read from the same sector by a number of times and a majority decision is done in the same address, thereby the most frequently read value is regarded as the true data value in the address. For example, for an address 00, “00” is handled as a true data value.

Claims

1. A data storage apparatus, comprising:

a head for writing/reading data in response to a write/read request received from a host;

a storage medium on/from which data is written/read by said writing/reading processing executed by said head;

storage means for temporarily storing pieces of read data read by said head a number of times from a predetermined area on said storage medium, individually; and

comparing means for comparing each piece of read data with others.

2. The data storage apparatus according to claim 1 wherein said comparing means decides matching/unmatching among data values in corresponding sections of said pieces of read data stored individually.

3. The data storage apparatus according to claim 2 wherein said apparatus further includes error correcting means that makes error correction for each data value in a section decided as unmatching by said comparing means.

4. The data storage apparatus according to claim 1 wherein said comparing means makes a majority decision for the data values in corresponding sections of said read pieces of data stored individually.

5. The data storage according to claim 4 wherein said comparing means regards the most frequently read value in said majority decision as a true data value in said section and generates a piece of read data by combining those true data values;

and

wherein said error correcting means makes error correction for the piece of read data generated by said combination.

6. A read data processor, comprising:

first deciding means that decides whether or not a data error occurs in a first piece of data read from each sector having a predetermined capacity;

reread instructing means that reads data again from said sector that contains said first piece of data decided as error data by said first deciding means, to obtain a second piece of data;

second deciding means that decides whether or not the values of said first and second piece of data in corresponding positions are different from each other; and

error correcting means that makes error correction for said first and second piece of data when said values are decided as different by said second deciding means.

7. The read data processor according to claim 6 wherein said second deciding means, when said second piece of data is decided as error data by said first deciding means, decides whether or not said values of said first and second pieces of data in corresponding positions are identical.

8. A read data processor that processes pieces of read data read from a storage medium having a track formed thereon, for each of a plurality of sectors, said track consisting of the plurality of sectors, said-apparatus comprising:

storage means that temporarily stores said n pieces of read data read n times (n;

natural number) from a predetermined sector;

identifying means that identifies the most frequently read value among said n pieces of read data read from each location in said sector; and

read data composing means that composes a generated piece of data generated by said most frequently read values identified for said locations by said identifying means.

9. The read data processor according to claim 8 wherein, when it is impossible to identify the most frequently read value among said n pieces of said read data read from each location in said sector, the value of said piece of read data read latest in a predetermined number of readings is identified as a value used to compose said generated piece of data in said location.

10. The read data processor according to claim 9 wherein said apparatus further includes error correcting means that makes error correction for said generated piece of data composed by said read data composing means.

11. A data storage apparatus, comprising:

a head that writes/reads data in response to a write/read request received from a host;

a storage medium on/from which data is written/read by said head;

first storage means that temporarily stores a piece of read data read from said storage medium by said head with the piece of read data divided and stored in predetermined units according to a predetermined rule; and

deciding means that decides whether or not an error occurs in said piece of read data divided and stored in each predetermined unit.

12. The data storage apparatus according to claim 11:

wherein said apparatus further includes error correcting means that makes error correction for the read data divisions in said predetermined units, respectively, when said piece of read data is decided as error data; and

wherein, after the error correction executed by said error correcting means, said deciding means decides, with respect to said read data decided as error data, whether or not error correction has been allowed for each read data division stored in the predetermined unit.

13. The data storage apparatus according to claim 12 wherein said apparatus further includes second storage means that temporarily stores said piece of read data in said predetermined unit, said data being decided as error correctable by said deciding means and corrected by said error correcting means.

14. The data storage apparatus according to claim 13 wherein said apparatus applies a predetermined process for allowing error correction to said predetermined unit having said piece of read data decided as error correctable by said deciding means.

15. The data storage apparatus according to claim 14 wherein said error correcting means applies an error correcting process to said predetermined unit over which a predetermined process for error correction is already applied;

and

wherein said second storage means stores said predetermined unit of data to which said error correcting process is applied.

16. The data storage apparatus according to claim 15 wherein said apparatus further includes editing means that generates said predetermined unit of data to be output on said host according to said piece of read data decided as error correctable by said deciding means and corrected by said error correcting means and said piece of read data decided as error uncorrectable by said deciding means and corrected by said error correcting means, both of said piece of data being read from said second storage means.

17. A read data processor that divides a piece of data read from each sector on a storage medium into a number of interleave sections and processes said piece of data, said apparatus, comprising:

storage means that stores each interleave section of said piece of data;

error deciding means that decides whether or not an error occurs in each interleave section; and

error correcting means that applies error correction to each interleave section;

wherein a piece of read data to be output to external is composed by a combination of interleave sections decided as error-occurred interleave sections by said error deciding means and corrected by said error correcting means.

18. A read data processing method, comprising the steps of:

reading a piece of user data from each sector on a storage medium;

deciding whether or not an error occurs in said piece of user data;

reading said piece of user data once or twice or more again from said sector that contains said error-detected piece of user data; and

making a comparison between the piece of user data initially read and the piece of user data next read with respect to their data values read from the same location.

19. The read data processing method according to claim 18 wherein a comparison is made among said data values to decide whether or not the data value in said location is varied each time it is read.

20. The read data processing method according to claim 19 wherein, when said data value is varied in said comparison, it is decided that an error has occurred in said data.

21. The read data processing method according to claim 19 wherein said comparison is made among data values to assume the most frequently matched data value as a true data value.

22. A read data processing method, comprising the steps of:

reading a piece of user data from each sector on a storage medium;

dividing said read user data into a number of interleave sections;

deciding whether or not an error occurrs in each of said interleave sections;

applying a first error correcting process to each interleave section decided as error data; and

applying a second error correcting process to each interleave section whose error is not corrected by said first error correcting process, said second error correcting processing being different from said first error correcting process.

23. The read data processing method according to claim 22 wherein a sector of read data to be output is composed by a combination of one or more interleave sections such as an interleave sections decided as containing no error, an interleave sections whose error is corrected by said first error correcting process, and interleave sections whose error is corrected by said second error correcting process.