Magnetic hard disk drive

• US 6,822,818 B2
• Filed: 08/02/2001
• Issued: 11/23/2004
• Est. Priority Date: 11/20/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi Global Storage Technologies Japan Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Ichihara, Takayuki, Takano, Hisashi, Akagi, Kyo, Hamaguchi, Takehiko
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): DAVIDSON, DAN
• Application Number:
  US09/919,915
• Publication Number:
  US 20020060871A1
• Time in Patent Office: 1,209 Days
• Field of Search: 360/77.08, 360/75, 360/48, 360/78.14
• US Class Current: 360/48
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/1252 for discontinuous data, e.g. digital information signals, computer programme data
• CPC Class Codes: G11B 2020/1232 sector, i.e. the minimal addressable physical data unit
• CPC Class Codes: G11B 2020/1238 track, i.e. the entire a spirally or concentrically arranged path on which the recording marks are located
• CPC Class Codes: G11B 2020/1267 Address data
• CPC Class Codes: G11B 2020/1287 Synchronisation pattern, e.g. VCO fields specific bit sequences of sync patterns G11B20/1403; A/V synchronisation G11B27/00
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 2220/2516 Hard disks
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/5582 system adaptation for working during or after external perturbation, e.g. in the presence of a mechanical oscillation caused by a shock
• CPC Class Codes: G11B 5/59611 Detection or processing of peak/envelop signals
• CPC Class Codes: G11B 5/59655 Sector, sample or burst servo format
• CPC Class Codes: G11B 5/59694 System adaptation for working during or after external perturbation, e.g. in the presence of a mechanical oscillation caused by a shock

Abstract

A hard disk drive and magnetic medium including a servo area, a data area divided into a plurality of sector blocks and at least one micro-servo area disposed between two sector blocks. There may be a micro-servo area immediately preceding each of the plurality of sector blocks. The micro-servo areas include an address mark and a track parity check code that allow the detection of an external shock that causes the recording (write) head to skip to an adjacent track in the hard disk medium. The micro-servo area is smaller than the servo areas, and various numbers of different track parity check codes can be used for different resolution of shock detection. An acceleration sensor may also be provided to detect larger external shocks. By detecting various external shocks with improved accuracy, and aborting the recording operation of data if an external shock is detected, the corruption of data in adjacent tracks is substantially reduced to improve disk drive performance.

Claims

1. A magnetic hard disk drive, comprising:

a magnetic hard disk comprising data areas divided into a plurality of sector blocks and at least one micro-servo area formed between at least two of said plurality of sector blocks, each micro-servo area including a parity code of a track number recorded therein;

a magnetic head comprising a reproducing element for converting magnetic information recorded on the magnetic hard disk into an electric signal and a recording element; and

a data processing circuit for processing magnetic information input or output from the magnetic head, wherein the data processing circuit comprises a means for detecting the parity code recorded in the micro-servo area.

2. The magnetic hard disk drive according to claim 1, wherein said magnetic disk further comprises servo areas each including servo information recorded therein, wherein said data areas each are formed between the servo areas, further wherein said micro-servo areas have a smaller area than said servo areas, and further wherein said parity code recorded in said micro-servo areas has a smaller data size than that of the servo information.

3. The magnetic hard disk drive according to claim 2, wherein there is a micro-servo area immediately before each of said plurality of sector blocks.

4. The magnetic hard disk drive according to claim 3, wherein an address mark and a track parity check code are recorded in the micro-servo area.

5. The magnetic hard disk drive according to claim 1, wherein the center line in the track direction of the micro-servo area is distant from the center line in the track direction of the sector block by a distance amount corresponding to the distance in the direction of track width between the recording element and the reproducing element.

6. The magnetic hard disk drive according to claim 4, wherein a track parity check code corresponding to a certain data area is different from a second track parity check code corresponding to a data area in at least one adjacent track.

7. The magnetic hard disk drive according to claim 6, wherein there are between 2 and 16 types of track parity check codes.

8. The magnetic hard disk drive according to claim 6, wherein the track parity check code has a data size of not more than 4 bits.

9. The magnetic hard disk drive according to claim 4, wherein in a first micro-servo area corresponding to a first data sector block and a second micro-servo area corresponding to a second data sector block adjacent in the direction of track width to the first data sector block, the starting points of the signal patterns representing their respective address marks or track parity check codes are aligned in the direction of track width.

10. The magnetic hard disk drive according to claim 4, wherein the servo area has an address mark field, and the signal pattern recorded in the address mark field of the micro-servo area is different from the signal pattern recorded in the address mark field of the servo area.

11. The magnetic hard disk drive according to claim 4, wherein the bit frequency of the micro-servo information signal pattern is the same as the bit frequency of the signal pattern recorded in the servo area.

12. The magnetic hard disk drive according to claim 1, further including an acceleration sensor.

13. A magnetic hard disk drive, comprising:

a magnetic hard disk having servo areas each including servo information recorded therein, data areas each formed between the servo areas and divided into a plurality of sector blocks, and micro-servo areas each formed between the plurality of the sector blocks and each having a smaller area than that of the servo area, wherein each micro-servo area includes track position information recorded therein having a smaller data size than that of the servo information;

a magnetic head having a reproducing element for converting magnetic information recorded on the magnetic hard disk into an electric signal and a recording element; and

a data processing circuit for processing magnetic information input or output from the magnetic head, wherein the data processing circuit identifies the track position information recorded in the micro-servo area corresponding to the sector block to which a recording operation is to be performed and allows the magnetic head to perform said recording operation if the track position information matches the track position information corresponding to the sector block to which the recording operation is performed at the time of the recording operation to the sector block.

14. The magnetic hard disk drive according to claim 13, wherein the data processing circuit aborts the recording operation of the magnetic head if the track position information does not match the track position information corresponding to the target sector block.

15. The magnetic hard disk drive according to claim 13, further comprising:

an acceleration sensor for detecting an external shock, wherein the data processing circuit allows the magnetic head to perform the recording operation only if the value of the acceleration detected by the acceleration sensor is smaller than a prescribed value determined by the specifications of the drive, and the track position information matches the track position information of the track to which the sector block to which the recording operation is performed belongs.

16. The magnetic hard disk drive according to claim 13, wherein if the track position information does not match the track position information of the track to which the target sector block belongs, the data processing circuit retries the recording operation up to a maximum number of times prescribed by the specifications of the drive.

17. The magnetic hard disk drive according to claim 13, further comprising a write gate controller for generating a write gate signal which determines the timing of starting the recording to the sector block, wherein the write gate controller makes the write gate signal active if the track position information matches the track position information of the track to which the target sector block belongs.

18. A magnetic disk medium for a magnetic hard disk drive, comprising:

a plurality of servo areas each including servo information recorded therein;

a plurality of data areas each formed between the servo areas and divided into a plurality of sector blocks; and

micro-servo areas each formed between the plurality of sector blocks and each having a smaller area than that of the servo area, wherein each micro-servo area includes a parity code of a track number recorded therein having a smaller data size than that of the servo information.

19. The magnetic disk medium according to claim 18, wherein an address mark and a track parity code are recorded in the micro-servo area.

20. The magnetic disk medium according to claim 19, wherein there are between 2 and 16 types of track parity check codes.