JP2008146753A - Magnetic recording device, magnetic recording method, and program for magnetic recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording device for accurately deciding the effect of ATI (Adjacent Track Interference) and for highly accurately preventing reading error of adjacent tracks due to the effect of ATI. <P>SOLUTION: When data is written in an ATI effect extent decision unit area S<SB>(n, x)</SB>, the ATI affected number of times C<SB>(n-1, x)</SB>, C<SB>(n+1, x)</SB>is counted regarding ATI effect extent decision unit area S<SB>(n-1, x)</SB>,<SB>(n+1, x)</SB>adjacent to the ATI effect extent decision unit area S<SB>(n, x)</SB>in the radial direction, respectively, and successively, it is decided whether the ATI affected number of times C<SB>(n-1, x)</SB>, C<SB>(n+1, x)</SB>is larger than the ATI guaranteed number of times N<SB>P</SB>or not. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic recording apparatus, a magnetic recording method, and a magnetic recording program, and more particularly to recording data on a magnetic recording medium in units of tracks including a plurality of sectors.

  A hard disk device is a magnetic recording device used for storing information. Normally, information is recorded on concentric tracks on one side of one or more magnetic recording disks. The disk is rotatably supported by a spindle motor. Information is written to and read from the track by a recording / reproducing head provided in the actuator arm. The actuator arm is rotated by a voice coil motor. The voice coil motor is excited by current to rotate the actuator and move the recording / reproducing head. The recording / reproducing head senses a change in magnetism emitted from the surface of the disk and reads information recorded on the disk surface. In order to record data on the track, current is supplied to the recording / reproducing head. The current supplied to the recording / reproducing head generates a magnetic field, which magnetizes the disk surface.

  Recently, for high-density recording, the distance between the recording / reproducing head and the disk is reduced to reduce the track interval. If the distance between the recording / reproducing head and the disk is reduced, when data is recorded on any of the tracks, the adjacent magnetic field may be overwritten by the leakage magnetic field generated by the recording / reproducing head. May result in the data recorded on the adjacent track being erased.

  This phenomenon is called data erasure of adjacent tracks by ATI (Adjacent Track Interference). Data erasure of adjacent tracks by ATI occurs when repetitive writing to the same sector is continued and reading / writing of the peripheral sector is not performed. Specifically, for example, it occurs when some record (communication record, error history, etc.) is used at a specific location of a specific file or a specific file as a ring buffer.

  In order to prevent data erasure of adjacent tracks by the ATI, the hard disk device of Patent Document 1 accumulates the number of times of data recording in at least one sector of the first track, and determines whether the accumulated number is greater than a predetermined number. If the accumulated number of times is determined and exceeds the predetermined number, a technique for re-recording data recorded on a track adjacent to the track to which the sector belongs has been proposed.

JP 2005-235380 A

  However, since the track is adjacent to the tracks on both sides, it is affected by the data recording of the tracks on both sides. In the configuration in which the data of the track is re-recorded according to the above, there is a problem that the influence of ATI cannot be accurately determined.

Also, in Patent Document 1, the number of times of data recording in at least one sector of the first track is accumulated, and when the accumulated number is greater than a predetermined number, the data of the track adjacent to the track to which the sector belongs is re-recorded. It is a configuration. FIG. 14 is a diagram for explaining a case where the influence of the ATI of the adjacent track is determined for each track. In FIG. 14, a total of the data of 640K bytes, if you write 10 times on a sector-by-sector basis to track T _n, influence the degree of impact on the adjacent track T _n-1 exactly is only a "1". However, as in Patent Document 1, in the control in units of tracks, since the track write is counted as the influence degree “1”, the influence degree is “10”, so the influence of the ATI is accurately determined. There is a problem that can not be.

  The present invention has been made in view of the above, and it is possible to accurately determine the influence of ATI (Adjacent Track Interference), and to accurately prevent reading errors in adjacent tracks due to the influence of ATI. It is an object to provide an apparatus, a magnetic recording method, and a magnetic recording program.

  In order to solve the above-described problems and achieve the object, the present invention provides a magnetic recording apparatus for recording data on a magnetic recording medium in which a plurality of tracks including a plurality of sectors are formed. When data is written in an ATI influence degree determination unit area composed of a plurality of servo areas, at least for the ATI influence degree determination unit area adjacent to the ATI influence degree determination unit area in the radial direction, Counting means for counting the number of write influences, or counting means for counting the number of writes in the ATI influence degree determination unit area where the data has been written, and whether the number of write influences or the number of writes is greater than a threshold First determination means for determining whether or not.

  According to a preferred aspect of the present invention, when the first determining means determines that the number of write influences is greater than a threshold, the ATI for which the number of write influences is determined to be greater than the threshold. It is determined whether the data of the sector in the influence determination unit area is affected by ATI (Adjacent Track Interference), or if it is determined that the number of times of writing is greater than a threshold, the number of times of writing is First, it is determined whether or not the ATI influence degree determination unit area determined to be larger than the threshold has an influence of ATI (Adjacent Track Interference) on the data of the sector of the ATI influence degree determination unit area adjacent in the radial direction. 2 and the second determination unit, the sector data determined to have an ATI effect are displayed. And recovery means for recovering the data, it is desirable to have a.

  According to a preferred aspect of the present invention, when the data of the sector determined to be affected by ATI is recovered by the recovery means, the write influence frequency of the ATI influence degree determination unit area is set to “0”. It is desirable to provide reset means for resetting to "".

According to a preferred aspect of the present invention, when the second determination unit writes data to the ATI influence degree determination unit area of the write target track, the non-write area in the ATI influence degree determination unit area It is determined whether the data of the sector of ATI has an influence,
Preferably, the recovery means recovers the data of the sector determined by the second determination means to have an ATI effect.

  According to a preferred aspect of the present invention, when the second determination unit reads data from the ATI influence degree determination unit area of the track to be read, the second determination unit converts the data of the sector in the ATI influence degree determination unit area into the data of the sector. It is preferable to determine whether or not there is an ATI effect, and it is preferable that the recovery means recovers the data of the sector determined by the second determination means to be affected by the ATI.

  Further, according to a preferred aspect of the present invention, it is desirable that the recovery means re-records data or performs sector replacement on a sector determined to be affected by ATI.

  Further, according to a preferred aspect of the present invention, it is desirable that the number of inter-servo areas constituting the inner ATI influence determination unit area is larger than that of the outer periphery.

  In order to solve the above-described problems and achieve the object, the present invention provides a magnetic recording method for recording data on a magnetic recording medium in which a plurality of tracks including a plurality of sectors are formed. When data is written in an ATI influence degree determination unit area composed of a plurality of servo areas, at least for the ATI influence degree determination unit area adjacent to the ATI influence degree determination unit area in the radial direction, Counting step of counting the number of write influences or counting the number of writes of the ATI influence degree determination unit area where the data has been written, and whether the number of write influences or the number of writes is greater than a threshold A first determination step of determining whether or not.

  According to a preferred aspect of the present invention, in a magnetic recording program for recording data on a magnetic recording medium on which a plurality of tracks including a plurality of sectors are formed, one or a plurality of consecutive servos is recorded for each track. When data is written in an ATI influence degree determination unit area configured by areas, at least the number of write influences in the ATI influence degree determination unit area adjacent to the ATI influence degree determination unit area in the radial direction Or a counting step for counting the number of writes in the ATI influence degree determination unit area where the data has been written, and whether or not the write influence number or the write number is greater than a threshold value And causing the computer to execute the first determination step.

  According to the magnetic recording apparatus of the present invention, the counting unit is configured such that, for each track, when data is written in the ATI influence determination unit area configured by one or a plurality of continuous servo areas, At least the ATI influence degree determination unit area that is adjacent to the ATI influence degree determination unit area in the radial direction is counted as the number of write influences, or the ATI influence degree determination unit area in which the data has been written is written. Since the number of times is counted and the first determining means determines whether the number of times of writing influence or the number of times of writing is greater than a threshold value, the influence of ATI (Adjacent Track Interference) is accurately determined. Provides a magnetic recording device that can accurately prevent adjacent track read errors due to ATI effects There is an effect that it becomes possible to do.

  Exemplary embodiments of a magnetic recording apparatus, a magnetic recording method, and a magnetic recording program according to the present invention will be explained below in detail with reference to the accompanying drawings. In the following embodiments, a case where the magnetic recording device according to the present invention is applied to a hard disk device will be described. In addition, this invention is not limited by the following Example. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

(Example 1)
FIG. 1 is a diagram showing a schematic configuration example of a hard disk device to which a magnetic recording device according to the present invention is applied. As shown in FIG. 1, the hard disk device 10 includes a disk 11, an SPM (Spindle Motor) 12, a head 13, an arm 14, a VCM (Voice Coil Motor) 15, a drive controller 16, and a read / write signal. A processing unit 17, a data memory 18, a hard disk controller 19, and a control unit 20 are provided.

  The disk 11 is a disk as a magnetic recording medium, and records various data input from the outside. The SPM 12 rotates the disk 11. The head 13 reads / writes signals from / to the disk 11. The arm 14 fixedly supports the head 13. The VCM 15 feeds the head 13 and the arm 14 in the radial direction of the disk 11. The drive control unit 16 includes drive circuits that drive the SPM 12 and the VCM 15, respectively, and performs drive control of the SPM 12 and the VCM 15.

  The read / write signal processing unit 17 outputs position information and sector data recorded in the servo area of the disk 11. Further, the read / write signal processing unit 17 encodes data to be written to the disk 11 and decodes data read from the disk 11, and at this time, performs encoding and error detection and error correction processing using an error correction code. Perform together.

  The data memory 18 buffers data read from the disk 11 and data to be written to the disk 11. The hard disk controller 19 constitutes an input / output circuit for data, control commands, etc. transmitted / received to / from a host device such as a personal computer or an AV device via an interface. Here, the interfaces are IDE (Integrated Drive Electronics), SCSI (Small Computer System Interface), FC (Fiber Channel), USB (Universal Serial Bus), and the like.

  The control unit 20 controls the entire operation of the hard disk device 10. The CPU 21 controls the operation of the hard disk device 10 according to the firmware (magnetic recording program) stored in the ROM 22, and the ROM 22 stores firmware executed by the CPU 21. The CPU 21 includes a RAM 23 used as a work area, a non-volatile memory 24 for storing an ATI guarantee table (see FIG. 2), and the like.

FIG. 2 is a diagram illustrating an example of the ATI guarantee table. In the ATI guarantee table, as shown in the figure, the number of ATI influences (number of write influences) C _{(n, x ) for} each ATI influence determination unit area S _{(n, x)} of each track T _n of the disk 11 ₎ Is recorded. The ATI influence degree determination unit area S _{(n, x)} is composed of an area composed of one or a plurality of continuous servo areas SBA in each track n. Here, n indicates a track number, and x indicates an area number in each track. The CPU 21 counts the number of ATI influence C _{(n, x)} for each ATI influence determination unit area S _{(n, x)} of each track Tn of the disk 11 and records it in the ATI guarantee table. The control unit 20 functions as a counting unit, a first determination unit, a second determination unit, a recovery unit, and a reset unit, and executes an ATI error prevention process and an ATI error countermeasure prevention process, which will be described later.

  An outline of the servo operation of the hard disk device 10 configured as shown in FIG. 1 will be described. In the hard disk device 10, the position information is read from the servo area of the disk 11 by the head 13 and is output to the control unit 20 via the read / write signal processing unit 17. Based on this position information, the control unit 20 drives the VCM 15 and the SPM 12 via the drive control unit 16 to move the head 13 to a predetermined position. Then, a data write or read operation is performed on the data area of the disk 11.

  Next, an outline of the data read / write operation of the hard disk device 10 will be described. When the hard disk controller 19 receives a command (such as a write / read command) issued from the host device via the interface, the hard disk controller 19 interprets the contents of the command and notifies the control unit 20 of the interpretation.

  The control unit 20 sets necessary commands and parameters for the drive control unit 16 and the read / write signal processing unit 17 on the basis of the notification contents, and executes those operations.

  The drive control unit 16 controls the drive of the SPM 12 and the VCM 15 to move the head 13 with respect to predetermined tracks and sectors on the disk 11. The read / write signal processing unit 17 encodes (modulates) the transmitted data into a digital bit sequence when writing to the disk 11. The read / write signal processing unit 17 removes high-frequency noise from the signal read from the head 13 at the time of reading, then performs conversion from an analog signal to a digital signal, and further corrects an ECC (Error Correction Code) error. I do. Here, the ECC error correction is performed at different levels depending on the degree of error in the read signal.

  The servo area of the disk and the ATI influence degree determination unit area will be described with reference to FIGS. 3 is a plan view of the disk 11, FIG. 4 is an enlarged plan view of a part of the disk 11 of FIG. 3, and FIG. 5 is a diagram for explaining an ATI influence degree determination unit area.

  As shown in FIGS. 3 and 4, concentric tracks T are formed on the disk 11 at substantially equal intervals. In the example shown in FIG. 4, only five tracks are shown by solid lines. However, in an actual magnetic disk device, tens of thousands of tracks T are formed over the inner and outer circumferences of the disk 11 with a track interval narrower than 1 μm. ing. The disk 11 is provided with servo areas SA at substantially equal rotation angle intervals in order to detect the radial position of the head. In the example shown in FIG. 3, for the sake of simplicity of illustration, eight servo areas SA are provided, but actually, about 50 to 150 are provided. A data area is provided between the servo areas SA, and an area between the servos is referred to as an inter-servo area SBA.

  The head 13 can be moved to an arbitrary radial position of the disk 11 by the actuator 14, but is fixed at a specific radial position when writing and reading data. In order to perform a following operation (following) with respect to a specific track, a special pattern called a servo pattern is recorded in advance on the disk 11 before product shipment, and a position signal is obtained from this pattern. The servo pattern is formed in the servo area SA. The servo area SA and the data area are separated by a gap for absorbing fluctuations in rotational speed. Further, when the hard disk device performs sector management with 512 bytes, this data area is divided into sector blocks of about 600 bytes, which is 512 bytes of user data plus management information. The servo area SA is not rewritten after product shipment, whereas the data area is frequently rewritten by a command from the user.

  In the servo area SA, a pattern in which the timing in the bit direction is synchronized between tracks adjacent in the radial direction is recorded. In order to form such a special pattern, a clock synchronized with the rotation of the disk is required. Normally, when recording a servo pattern, the servo pattern is recorded by a device called a servo track writer having such a function. Since the formation method of the servo pattern is known, its detailed description is omitted.

In the present embodiment, when the influence of ATI on the adjacent track due to the writing of the track data is determined, the determination is made in the ATI influence determination unit area S _{(n, x)} instead of the track unit. FIG. 5 shows an example of the ATI influence degree determination unit area. In FIG. 5, the number of servo areas SA is eight for the sake of simplicity. The ATI influence degree determination unit area S _{(n, x)} is composed of an area composed of one or a plurality of consecutive servo areas SBA in each track T _n . In the example shown in the figure, two consecutive inter-servo areas SDA are collectively used as an ATI influence determination unit area S _{(n, x)} . Specifically, the inter-servo areas “SBA1 and SBA2”, “SBA3 and SBA4”, “SBA5 and SBA6”, and “SBA7 and SBA8” of the track Tn are respectively set to the ATI influence determination unit area “S _{(n, 1 )} "," S _{(n, 2)} "," S _{(n, 3)} "," S _{(n, 4)} ".

The number of inter-servo areas SBA constituting the ATI influence determination unit area S _{(n, x)} does not have to be the same for all tracks, and an optimum value different for each track or a plurality of tracks can be selected. (In FIG. 2, a ≠ b ≠... ≠ z). Since the number of sectors included in the inter-servo area SBA is smaller in the inner circumference (large track number) than in the outer circumference (small track number) of the disk 11, the ATI influence determination unit area S in the inner circumference (large track number). It is desirable to increase the number of inter-servo areas that constitute _{(n, x)} as compared to the outer circumference (small track number) (a ≧ b ≧... ≧ z in FIG. 2).

A method for preventing the influence of ATI in this embodiment will be described with reference to FIGS. FIG. 6 is a diagram for explaining the principle of occurrence of ATI. Here, a description will be given _{assuming that} the write target is the ATI influence determination unit area S _{(n, x)} of the track T _n . When a magnetic field is generated by the head 13 in the ATI influence determination unit area S _{(n, x)} on the track T _n , the ATI influence determination unit area S _{(n, x)} is magnetized. The ATI influence degree determination unit areas S _{(n−1, x)} and S _{(n + 1, x)} adjacent in the radial direction are slightly affected by the leakage magnetic field. Here, the ATI effect degree determination unit area S _{(n, x)} is continuously-repeated data to be recorded, adjacent in the radial direction with respect to the ATI effect degree determination unit area S _{(n, x)} ATI The data recorded in each of the influence determination unit areas S _{(n−1, x)} and S _{(n + 1, x)} has a higher probability of being erased or damaged as the number of recordings is accumulated, and a reading error occurs. There is a case.

  Here, the error stage due to the influence of ATI will be described. (1) Since the influence of ATI is small at the initial stage, the influence of demagnetization is small, so that it can be read without problems by ECC (error correction processing) with no error or a small correction capability (correction capability) (no error, Minor soft error condition). (2) When the influence of ATI is in the middle stage, it begins to be affected by demagnetization, but by ERP (error recovery processing), the ECC correction capability is increased, the head position is removed from the center of the track, the read signal amplification factor is increased, etc. Can be read (moderate soft error condition). (3) At the later stage of the influence of ATI, sufficient read signal characteristics cannot be obtained due to the effect of demagnetization, and it becomes impossible to read intermittently or not to read at all (severe soft error, hard error Status = read error).

  In this embodiment, the influence of ATI is prevented in advance at the stage of (2) moderate soft error, and the occurrence of read errors (severe soft error, hard error) due to the influence of ATI is prevented. To do. FIG. 7 is a diagram for explaining the influence of the ATI of the read signal.

As shown in FIG. 7, the output level of the read signal decreases as the influence of ATI increases. Therefore, the ECC correction capability for recovering the read error is gradually required to be large. In this embodiment, for example, in the sector in the ATI influence determination unit area S _{(n−1, x) of the (n−1)} th track Tn−1, the intermediate soft error stage (2) described above. in ECC correction capability P used it is required adjacent ATI effect degree determination unit area S _{(n, x)} or a S _{(n-2, x)} guarantee ATI number n _p the number of write operations.

This guaranteed ATI count N _p is a value obtained for each hard disk device by design and process evaluation. This is because the write head width, the write characteristics, the head flight altitude, and the magnetic retention characteristics of the media magnetic layer differ for each hard disk device. The number of guaranteed ATIs N _p can be, for example, tens of thousands to hundreds of thousands of times.

In this embodiment, the control unit 20, ATI effect degree determination unit area S _{(n, x)} each time the data recording is performed, ATI impact adjacent in the radial direction determination unit area S _{(n-1, x ) And} S _{(n + 1, x)} are counted as ATI influence times C _{(n−1, x)} and C _{(n + 1, x)} . The ATI influence count C is recorded in the ATI guarantee table as described above. When the ATI influence count C exceeds the guaranteed ATI count N _p , the control unit 20 executes ATI error prevention processing, reads the data of the sector in the ATI impact determination unit area, determines the influence of ATI, By performing ATI error prevention measures (data re-recording, sector replacement, etc.) for sectors affected by ATI, data read errors (severe soft errors, hard errors) caused by ATI Prevent the occurrence.

The write process executed under the control of the control unit 20 will be described with reference to FIGS. FIG. 8 is an explanatory diagram for explaining the writing process, and FIGS. 9-1 and 9-2 are flowcharts for explaining the writing process. In the following description, the case where the write target is the ATI influence degree determination unit area S _{(n, x)} of the track T _n will be described.

In FIG. 8, in the write process, data is written to the write area (write target sector) of the ATI influence determination unit area S _{(n, x)} , and the non-write areas (1) and (2) are written to the sectors. On the other hand, the influence of the current ATI is confirmed.

9A and 9B, first, seek to the target track T _n (step S1). Thereafter, when the seek is completed, the writing process is performed in units of sectors from the head sector, and the determination of ATI influence is performed in the ATI influence determination unit area S _{(n, x)} . Subsequently, it is determined whether or not the target sector is a write area sector (step S2). If the target sector is not a write area sector (“No” in step S2), data in the non-write area (1) sector is read (step S3), and it is determined whether there is an ATI effect (soft error). (Step S4).

Here, whether or not there is an influence of ATI is determined based on whether or not the read data has the ECC correction capability P used in the above-described soft error stage. Specifically, when the read / write signal processing unit 17 uses an ECC correction capability equal to or higher than the ECC correction capability P for the read data, it is determined that there is an influence of ATI. If it is determined that there is no ATI influence (moderate soft error) (“No” in step S4 ₎ , confirmation of all sectors in the ATI influence determination unit area S _{(n, x)} is completed. It is determined whether or not (step S18).

If all the sectors in the ATI influence determination unit area S _{(n, x)} have not been confirmed (“No” in step S18), the process returns to step S2 to process the next sector. . On the other hand, when all the sectors in the ATI influence determination unit area S _{(n, x)} have been confirmed (“Yes” in step S18), the ATI of the ATI influence determination unit area S _{(n, x)} After setting the number of influences C _{(n, x)} = 0 ((step S19), the process returns to step S2 to perform processing for the next sector.

  If it is determined that there is an ATI effect (medium soft error) (“Yes” in step S4), the sector number and the read data are temporarily stored in the RAM 23 as an ATI affected sector. Later (step S5), the process returns to step S2, and the next sector is processed.

On the other hand, if the target sector is a write area sector in step S2 ("Yes" in step S2), data is written to the write area sector (step S6). Then, the ATI influence determination unit area S _{(n−1, x)} adjacent to the target ATI influence determination unit area S _{(n, x)} in the radial direction and the number of ATI influences of S _{(n + 1, x)} Each of C _{(n-1, x)} and C _{(n + 1, x)} is incremented by 1 (step S7).

Subsequently, it is determined whether or not there is an unread sector in the target track T _n (step S8). If there is an unread sector in the target track T _n (“Yes” in step S8), no writing is performed. The data of the sector in the area (2) is read (step S9), and it is determined whether or not there is an influence of ATI (medium soft error) (step S10). The method for determining the influence of ATI is the same as in step S4.

  If it is determined that there is no ATI effect (medium soft error) (“No” in step S4), the process returns to step S8 and the same process is performed for the next sector. If it is determined that there is an ATI effect (moderate soft error) (“Yes” in step S10), the sector number and the read data are temporarily stored in the RAM 23 as an ATI affected sector ( Step S11), returning to step S8, the same processing is performed for the next sector.

On the other hand, if there is no unread sector in the target track T _n (“No” in step S8), it is determined whether there is an ATI-affected sector stored in the RAM 23 in steps S5 and S11 (step S12). . If there is no ATI-affected sector (“No” in step S12), it is determined whether or not all sectors in the ATI influence determination unit area S _{(n, x)} have been confirmed (step S20).

If the confirmation of all sectors in the ATI influence determination unit area S _{(n, x)} has not been completed (“No” in step S20), the process returns to step S12 to confirm the next sector. On the other hand, when the confirmation of all the sectors in the ATI influence determination unit area S _{(n, x)} is completed (“Yes” in step S20), the ATI of the ATI influence determination unit area S _{(n, x)} . After setting the number of influences C _{(n, x)} = 0 (step S21), the process proceeds to step S14.

If the ATI effect sector is present (the "Yes" in step S12), the after executing the ATI error prevention countermeasure processing, ATI effect count C _{(n, x)} of the ATI effect degree determination unit area S _{(n, x)} It resets to “0” (step S13), and proceeds to step S14. In the ATI error prevention countermeasure process, the occurrence of an ATI error is prevented by performing re-recording of data (data after ECC error correction), sector replacement (recording data in different sectors), or the like.

In step S14, it is determined whether or not ATI influence count C _{(n-1, x)} > ATI guarantee count Np of ATI influence determination unit area S _{(n-1, x)} . If the ATI influence count C _{(n-1, x) of the} ATI influence determination unit area S _{(n-1, x)} > ATI guaranteed count Np is not satisfied (“No” in step S14), the process proceeds to step S16. When the ATI influence count C _{(n-1, x)} > ATI guarantee count N _p in the ATI influence determination unit area S _{(n-1, x) (} “Yes” in step S14), the ATI influence count After executing the ATI error prevention process (see FIG. 8 ₎ for the determination unit area S _{(n−1, x)} (step S15), the process proceeds to step S16.

In step S16, it is determined whether or not ATI influence count C _{(n + 1, x)} > ATI guarantee count Np of ATI influence determination unit area S _{(n + 1, x)} . If the ATI influence count C _{(n + 1, x) in the} ATI influence determination unit area S _{(n + 1, x)} is not greater than the ATI guarantee count Np (“No” in step S16), the flow ends. When the ATI influence count C _{(n + 1, x)} > ATI guarantee count N _p in the ATI influence determination unit area S _{(n + 1, x) (} “Yes” in step S16), the ATI influence degree After executing the ATI error prevention process (see FIG. 11 ₎ for the determination unit area S _{(n + 1, x)} (step S17), the flow ends.

With reference to FIG. 10 and FIG. 11, the reading process and the ATI error prevention process executed under the control of the control unit 20 will be described. FIG. 10 is an explanatory diagram for explaining the reading process, and FIG. 11 is a flowchart for explaining the reading process and the ATI error prevention process. In the following description, a case where T _m (where m = 1 to N) is a target track for reading or ATI error prevention processing will be described.

  In FIG. 10, in the read process, the influence of the current ATI is confirmed on the read non-target areas (1) and (2) and the read area sectors. Here, the read area is an area where the data is recorded when a data read request is received from the outside. The difference between the reading process and the ATI error prevention process is whether or not there is a read target area. In the case of the ATI error prevention process, all the areas are not to be read. In FIG. 10, the reading process and the ATI error prevention process will be described together without particularly distinguishing the reading area and the non-reading area.

11, first, seek to the target track T _m (step S31). Thereafter, processing is performed in units of sectors from the leading sector when the seek is completed. Decides whether the completed for all the sectors in the target track T _m (step S32). Whether if it is not completed for all the sectors in the target track T _m is ( "No" in step S32), reads the data of the sector (Step S33), (soft errors moderate) effects of ATI Is determined (step S34).

  If it is determined that there is no ATI effect (medium soft error) (“No” in step S34), the process returns to step S32 and the same process is performed for the next sector. If it is determined that there is an ATI effect (medium soft error) (“Yes” in step S34), the sector number and read data are temporarily stored in the RAM 23 as an ATI affected sector ( In step S35), the process returns to step S32, and the same process is performed for the next sector.

On the other hand, it is determined in step S32, ( "Yes" in step S32) if completed for all the sectors in the track T _m, whether ATI impact sectors stored in RAM23 in step S35 is present (step S36). If there is no ATI-affected sector (“No” in step S36), the flow ends. On the other hand, if there is an ATI-affected sector (“Yes” in step S36), the ATI error prevention countermeasure process is executed. Then, the ATI influence count C _{(m, x)} of the ATI influence degree determination unit area S _{(m, x)} is reset to “0” (step S37), and the flow ends.

As described above, according to the first embodiment _, when data is written in the ATI influence determination unit area S _{(n, x)} of the track T _n , the ATI influence determination unit area S _{(n , x)} ATI influence determination unit areas S _{(n−1, x)} and S _{(n + 1, x)} adjacent to each other in the radial direction ATI influence times C _{(n−1, x)} and C _{(n + 1) , x)} , respectively, and subsequently, it is determined whether or not ATI influence count C _{(n-1, x)} , C _{(n + 1, x)} > ATI guarantee count N _p . It is possible to accurately determine the influence of ATI, and to prevent the occurrence of an adjacent track read error due to ATI with high accuracy.

According to the first embodiment, when the number of ATI influences C _{(n−1, x)} and C _{(n + 1, x)} > the number of guaranteed ATIs Np, the track T _n−1 and the track T _{n +} run the ATI error preventive treatment for _1, ATI effect degree determination unit area _{S (n-1, x)} , the data of all the sectors of the _{S (n + 1, x)} , whether there is an influence of ATI Judgment and execution of ATI error prevention measures (data re-recording and sector replacement) for the sectors affected by ATI are performed to recover the data. To prevent the occurrence of adjacent track read errors (severe soft errors, hard errors) due to ATI, accurately determine the effects of ATI, and prevent the occurrence of adjacent track read errors due to ATI This can be prevented with high accuracy.

Further, according to the first embodiment, after executing the ATI error prevention measure process (data re-recording or sector replacement), the ATI influence degree determination unit areas S _{(n−1, x)} and S _{(n + 1, x)} Since the ATI influence count C _{(n−1, x)} and C _{(n + 1, x)} are reset to “0”, the ATI influence degree determination unit area S _{(n, x)} after data recovery It becomes possible to prevent the ATI influence of the ATI influence degree determination unit areas S _{(n−1, x)} and S _{(n + 1, x) on} writing with high accuracy.

Further, according to the first embodiment, when data is written to the target track T _n , it is determined whether or not the data of the sector in the non-write area in the track T _n has an ATI effect. Since ATI error prevention countermeasure processing (data re-recording and sector replacement) is executed for a certain sector to recover the data, the influence of ATI in the sector of the non-write area in the write target track T _n It is possible to prevent the occurrence of a read error due to the above with high accuracy.

Furthermore, according to the first embodiment, when reading data from the read target track T _m, determines whether there is an abnormality in the data sectors in the track T _m, with respect to sectors are affected by the ATI Since the data recovery is performed by executing the ATI error prevention countermeasure process (data re-recording and sector replacement), the occurrence of a read error due to the influence of ATI in the sector in the read target track T _m is highly accurate. It becomes possible to prevent.

Further, according to the first embodiment, the number of inter-servo areas constituting the ATI influence determination unit area on the inner circumference side is larger than that on the outer circumference side. It is possible to efficiently set the ATI influence determination unit area S _{(n, x)} according to the number.

  If the ATI influence determination is managed in the ATI influence determination unit area as in this embodiment instead of managing the influence of the ATI in the track unit, the frequency of the ATI countermeasure is executed as follows. The memory usage efficiency and the time required for ATI countermeasures are superior.

(1) Size of ATI guarantee table When managing in units of ATI impact determination unit area, the size of the ATI guarantee table is an ATI impact determination unit area that divides one track as compared to managing in units of tracks. Is required. However, since writing and reading by the OS are normally performed on a very limited area, the ATI guarantee table does not need to exist in the real memory, and only the part that is frequently used is the real memory. In other words, an area that is less frequently used may be saved on the disk.

(2) Activation frequency of ATI countermeasure processing routine by updating ATI table When managing in units of tracks, updating the ATI guarantee table is not required when files larger than a certain size are repeatedly written (such as periodic backup by an application). Therefore, the ATI countermeasure processing routine is also executed accordingly, and the performance at that time decreases. For example, in a HDD in which one track is 1024 sectors and the servo interval is 64 sectors, when a file of 512 Kbytes or more is written in units of 64 sectors, the ATI guarantee table that is subject to one write is (I) tracks The difference is an increase of “32” in units, and an increase of “1” in (II) ATI influence degree determination unit area units (actually, the adjacency effect is only 1, but the same in the case of track unit management. Because it cannot be distinguished whether writing to a sector or writing to a continuous sector). When the ATI security table reaches 10,000 and this file is written every 5 minutes on the HDD where ATI countermeasure processing is performed, (I) about 26 hours (1 in 2 days) in track units. (II), and (II) ATI influence determination unit area units are approximately every 833 hours (about once in March).

(3) Buffer amount for reading original data in ATI countermeasure processing When managing in units of tracks, the buffer required for reading data once is one track for the ATI countermeasure processing (divided reading is performed) And the performance impact is large). In this case, if the write cache is to be diverted, writing must be performed for the cache flush, and this also causes an ATI effect. Therefore, it is considered that the read cache is used. For this reason, in order to improve the performance, it is necessary to discard the previously read data for one track. For example, when one track is 1024 sectors, the real memory is 8 Mbytes and half is used for the read cache, the read cache is equivalent to 7 tracks. But one-seventh the read cache must be thrown away. On the other hand, in the case of the ATI influence determination unit area unit, if there are 64 sectors between servos, the area may be small enough to fill an unused cache at that time.

(4) Time for confirming original data in ATI countermeasure processing When managing in track units, in order to read data for ATI countermeasure processing, at least the head movement time to the adjacent track + rotation to the target position A waiting time is required. When managing in units between servos, it is necessary to move the head to the adjacent track + rotation waiting time to the target position + reading time to the target sector. For example, in a 4200-rotation HDD, since the rotation time of one rotation is about 14 milliseconds and the normal head moving time is about 12 milliseconds, it takes 26 milliseconds or more. On the other hand, in the case of the ATI influence determination unit area unit, even if it takes about 0.5 milliseconds to write 64 sectors, the adjacent track for which it is determined that ATI countermeasures are necessary after that, Even after moving the head, there is a margin of 1 millisecond or more, and the ATI influence degree of the target sector can be confirmed without waiting for unnecessary rotation.

(5) Time to rewrite original data even in ATI countermeasure processing When there is an ATI effect, the ATI countermeasure processing writes (I) the original data to the management area and (II) save data so that the original data is not lost. (III) The saved data is written to the original position, and (IV) the written data is confirmed to be read. At that time, in the case of the ATI influence determination unit area unit, since the amount of data to be rewritten is small, the time required for (I) to (II) and (III) to (IV) among the above can be reduced.

(Example 2)
FIG. 12 is a flowchart for explaining the writing process according to the second embodiment. In FIG. 12, steps that perform the same processing as in FIG. 9 are given the same step numbers. The writing process (FIGS. 8 and 9) according to the first embodiment is configured to check the influence of ATI on the non-writing area. In contrast, the writing process according to the second embodiment has a configuration in which the influence of ATI is not confirmed on the non-writing area. The writing process shown in FIG. 12 is obtained by deleting steps S3 to S5 and S8 to 13 in FIG. 9, and the other steps perform the same process, and thus detailed description thereof is omitted.

  In addition, although the read process according to the first embodiment is configured to check the influence of ATI, the read process may be configured not to check the influence of ATI.

(Example 3)
The writing process according to the third embodiment will be described with reference to FIG. In the first and second embodiments, when data is written to the ATI influence determination unit area S _{(n, x)} , the ATI influence determination unit area S _{(n−1, x)} adjacent in the radial direction, S _{(n + 1, x)} of the ATI impact times _{C (n-1, x)} , as _{C (n + 1, x)} , which is configured to count. On the other hand, in the third embodiment _, when data is written in the ATI influence degree determination unit area S _{(n, x)} in FIG. When the number of writes in the area S _{(n, x)} exceeds the ATI guaranteed number N _p , the ATI influence determination unit area that is adjacent to the ATI influence determination unit area S _{(n, x)} in the radial direction The degree of influence of ATI on S _{(n-1, x)} and S _{(n + 1, x)} is determined.

According to the third embodiment, when data is written to the ATI influence determination unit area S _{(n, x)} of the track Tn, the number of times of writing in the ATI influence determination unit area S _{(n, x)} is performed. And the number of times of writing in the ATI influence determination unit area S _{(n, x)} > ATI guaranteed number of times N _p is determined. It is possible to prevent the occurrence of a read error in an adjacent track with high accuracy.

Example 4
The hard disk device 10 according to the first to third embodiments can be widely applied to personal computers (PS), AV devices (for example, video recorders) and the like. FIG. 13 is a diagram showing a case where the hard disk device 10 of the first to third embodiments is applied to a personal computer. As shown in FIG. 13, the personal computer 100 includes a CPU 101, a ROM 102, a RAM 103, a display device 104, an input device 105, an FD drive 106 that reads / writes data from / to the FD 108, and a DVD / CD 109. A DVD / CD drive 107 that reads the data, a communication I / F 110, and a hard disk device 10.

  Although the hard disk device has been described in the above embodiment, the magnetic recording device according to the present invention is not limited to the hard disk device, and other magnetic recording media for recording data in units of tracks, such as a flexible disk, The present invention can also be applied to a CD-R (Compact Disk-Recordable), DVD-R (Digital Versatile Disk-Recordable), and magneto-optical disk recording apparatus.

  The magnetic recording device, the magnetic recording method, and the magnetic recording program according to the present invention are widely applicable to various magnetic recording devices that record data on a magnetic recording medium, and are particularly useful for hard disk devices.

It is a figure which shows the example of a schematic structure of the hard disk drive to which the magnetic recording device concerning this invention is applied. It is a figure which shows the structural example of an ATI guarantee table. It is a top view of a disk. It is the top view to which a part of disk was expanded. It is a figure for demonstrating an ATI influence degree determination unit area. It is a figure for demonstrating the generation | occurrence | production principle of ATI. It is a figure for demonstrating the influence of ATI of a read signal. It is explanatory drawing for demonstrating the write-in process of a hard-disk apparatus. 6 is a flowchart for explaining a writing process of the hard disk device (part 1); 12 is a flowchart for explaining a writing process of the hard disk device (part 2). It is explanatory drawing for demonstrating the read-out process of a hard-disk apparatus. 6 is a flowchart for explaining a read process of the hard disk device and an ATI error prevention process. It is a flowchart for demonstrating the other Example of a write-in process. It is a figure which shows the structural example of a personal computer. It is a figure for demonstrating a prior art.

Explanation of symbols

10 Hard disk device 11 Disk 12 SPM
13 Head 14 Arm 15 VCM (Voice Coil Motor)
16 Drive Control Unit 17 Read / Write Signal Processing Unit 18 Data Memory 19 Hard Disk Controller 20 Control Unit 21 CPU
22 ROM
23 RAM
24 Nonvolatile memory 100 Personal computer 101 CPU
102 ROM
103 RAM
104 Display device 105 Input device 106 Drive 107 DVD / CD drive 108 FD
109 DVD / CD
110 Communication I / F

Claims (9)

In a magnetic recording apparatus for recording data on a magnetic recording medium in which a plurality of tracks including a plurality of sectors are formed,
For each track, when data is written in an ATI influence degree determination unit area composed of one or a plurality of consecutive servo areas, at least the ATI influence degree determination unit area adjacent in the radial direction is written. Counting means for counting the number of write influences for the ATI influence determination unit area, or counting the number of writes of the ATI influence determination unit area where the data has been written,
First determination means for determining whether the number of write influences or the number of writes is greater than a threshold;
A magnetic recording apparatus comprising: If it is determined by the first determination means that the number of write influences is greater than a threshold, the ATI influence degree determination unit area sector data for which the number of write influences is determined to be greater than the threshold It is determined whether there is an influence of (Adjacent Track Interference),
Alternatively, when it is determined that the number of times of writing is greater than a threshold value, an ATI influence degree determination unit adjacent in the radial direction with respect to the ATI influence degree determination unit area where the number of times of writing is determined to be greater than the threshold value Second determination means for determining whether or not the data of the sector of the area is affected by ATI (Adjacent Track Interference);
Recovery means for recovering data of a sector determined by the second determination means to be affected by ATI;
The magnetic recording apparatus according to claim 1, further comprising:   When the data of the sector determined to be affected by ATI is recovered by the recovery means, a reset means is provided for resetting the write influence frequency of the ATI influence degree determination unit area to “0”. The magnetic recording apparatus according to claim 1, wherein the magnetic recording apparatus is a magnetic recording apparatus. When the second determination means writes data to the ATI influence degree determination unit area of the track to be written, whether the data of the sector in the non-write area in the ATI influence degree determination unit area has an ATI influence Determine whether or not
3. The magnetic recording apparatus according to claim 1, wherein the recovery unit recovers data of a sector determined by the second determination unit as having an influence of ATI. 4. The second determination means determines whether or not the data of the sector in the ATI influence degree determination unit area has an ATI influence when reading data from the ATI influence degree determination unit area of the track to be read. ,
3. The magnetic recording apparatus according to claim 1, wherein the recovery unit recovers data of a sector determined by the second determination unit as having an influence of ATI. 4.   6. The magnetic recording according to claim 1, wherein the recovery unit re-records data or performs sector replacement on a sector determined to be affected by ATI. apparatus.   7. The magnetic recording apparatus according to claim 1, wherein the number of inter-servo areas constituting the ATI influence degree determination unit area on the inner circumference is larger than that on the outer circumference. . In a magnetic recording method for recording data on a magnetic recording medium in which a plurality of tracks including a plurality of sectors are formed,
For each track, when data is written in an ATI influence degree determination unit area composed of one or a plurality of consecutive servo areas, at least the ATI influence degree determination unit area adjacent in the radial direction is written. For the ATI influence determination unit area, a counting step of counting the number of write influences or counting the number of writes of the ATI influence determination unit area where the data has been written,
A first determination step of determining whether the number of write influences or the number of writes is greater than a threshold;
A magnetic recording method comprising: In a magnetic recording program for recording data on a magnetic recording medium in which a plurality of tracks including a plurality of sectors are formed,
For each track, when data is written in an ATI influence degree determination unit area composed of one or a plurality of consecutive servo areas, at least the ATI influence degree determination unit area adjacent in the radial direction is written. For the ATI influence determination unit area, a counting step of counting the number of write influences or counting the number of writes of the ATI influence determination unit area where the data has been written,
A first determination step of determining whether the number of write influences or the number of writes is greater than a threshold;
A program for magnetic recording that causes a computer to execute.

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