JP2005339802A - Burst displacement data writing method and magnetic disk unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To write burst displacement data of control information onto a magnetic disk in a surely readable condition concerning a data writing method and a magnetic disk unit. <P>SOLUTION: A burst displacement data writing method is disclosed for writing, onto the magnetic disk continuously after a burst pattern for correcting deviation within one track, burst displacement data for correcting the displacement of the burst pattern, wherein a write head is moved to a reversely offset position by the same offset amount as deviation to offset the write head so that the center of the core width of the write head coincides with the burst boundary of the burst pattern to write the burst displacement data when a normal data writing operation is changed to a normal data reading operation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a burst position deviation data writing method and a magnetic disk apparatus, and more particularly to burst position deviation data used for correcting a burst pattern position deviation when reading servo information written in advance on a magnetic disk. The present invention relates to a burst position deviation data writing method and a magnetic disk device for readable on a magnetic disk.

  Some magnetic disks employ a so-called embedded servo system in which servo information is previously written in data on a data surface without providing a dedicated servo surface. Servo information is used to accurately detect the movement of the head in the off-track direction on the magnetic disk. For example, the servo information is written in advance on the magnetic disk by a servo track writer (STW: Servo Track Writer) dedicated to writing servo information. .

  For example, as shown in FIG. 1, the servo frame format in which servo information is written includes the start of a read / write recovery area and a servo pattern area for absorbing a transient generated when switching from a data write operation to a servo read operation. It includes a servo mark area for confirmation, a gray code area where cylinder address information is coded, a position area where a burst signal is written, a gap area indicating the end of the servo frame, and the like. The position area includes a burst pattern area in which a burst pattern for correcting deviation in one track is written, and a burst position deviation data area in which burst position deviation data for correcting the positional deviation of the burst pattern is written. The burst position deviation data is sometimes referred to as RRO correction data that corrects repeatable run-out (RRO).

  FIG. 2 is a diagram showing the arrangement of burst position deviation data written on the magnetic disk by the conventional burst position deviation data writing method when the feed pitch is 1/2 track. In the figure, a thick solid line indicates a boundary line between adjacent cylinders (or tracks), and a broken line indicates the center of the cylinder (or track). Accordingly, in the figure, the vertical direction corresponds to the radial direction of the magnetic disk, and the horizontal direction corresponds to the circumferential direction of the magnetic disk. The burst position deviation data 2 written following the burst pattern 1 corrects the deviation of the write head 3 from the center of the on-track cylinder and the deviation of the read head 4 from the center of the on-track cylinder. Used for

  The core width 3-CW of the write head 3 is about 75% of the cylinder width 6, and the core width 4-CW of the read head 4 is about 50% of the cylinder width 6. For this reason, an area 5 in which burst position deviation data is not written occurs in the position area as indicated by the shaded portion in FIG. When the positional deviation from the target cylinder of the read head 4 immediately after seeking is relatively small, the read head 4 can read the burst position deviation data 2 as indicated by P1 in FIG. However, when the positional deviation of the read head 4 from the target cylinder is relatively large, the read head 4 may scan the area 5 where the burst positional deviation data 2 is not written, as indicated by P2 in FIG. Therefore, there is a possibility that the burst position deviation data 2 cannot be read.

  Therefore, the present inventors have studied a possible burst position deviation data writing method for avoiding the above problems. FIG. 3 is a diagram showing the arrangement of burst position deviation data written on the magnetic disk by this conceivable burst position deviation data writing method when the feed pitch is 1/2 track. In the figure, the same parts as those in FIG.

In this conceivable burst position deviation data writing method, the burst position deviation data 2 is overwritten in the circumferential direction of the magnetic disk, so that an area 5 in which the burst position deviation data 2 is not written as shown in FIG. Occurrence can be prevented. However, since the burst position deviation data 2 is repeatedly written, a portion in which the burst position deviation data 2 in the radial direction is overwritten is generated, and a write phase deviation 7 occurs as shown in FIG. Such a portion in which the burst position deviation data 2 in the radial direction is overwritten is written when the core width 3-CW of the write head 3 is larger than twice the boundary interval of the burst pattern 1, that is, the write head 3 This occurs when the core width 3-CW is larger than the cylinder width 6. When the burst position deviation data 2 including such a write phase deviation 7 is read, there is a possibility that the burst position deviation data 2 cannot be correctly recognized.
JP-A-10-27442 Japanese Patent Laid-Open No. 7-6525 JP-A-9-35255

  As described above, the burst position deviation data written on the magnetic disk by the conventional burst position deviation data writing method indicates that the read head bursts when the position deviation from the target cylinder of the read head immediately after seeking is relatively large. Since there is a possibility of scanning an area where no positional deviation data is written, there is a problem that reading may not be possible.

  In addition, even if the positional deviation from the target cylinder of the read head immediately after seeking is relatively large, the burst positional deviation data written on the magnetic disk by the possible burst positional deviation data writing method examined by the present inventors, Since the read head always scans the area where the burst position deviation data is written, it can be read reliably, but it cannot be correctly recognized due to the write phase deviation caused by the repeated writing of the burst position deviation data. There was a problem that there was a possibility.

  Accordingly, an object of the present invention is to provide a burst position deviation data writing method and a magnetic disk apparatus that can write burst position deviation data of control information onto a magnetic disk so as to be surely readable.

  The above problem is a burst position deviation data writing method for writing burst position deviation data for correcting a positional deviation of the burst pattern on a magnetic disk, following a burst pattern for correcting the deviation within one track. N is an integer greater than or equal to WHD, the core width of the write head, the interval K between the burst boundaries of the burst pattern, and the number M of areas of the burst misalignment data that need to be provided after the burst pattern. Then, in the case of (N-1) K <WHD <NK, it can be achieved by a burst position deviation data writing method including a step of writing the burst position deviation data so that the relationship of M = N is established. .

  The above problem is a burst position deviation data writing method for writing burst position deviation data for correcting a positional deviation of the burst pattern on a magnetic disk, following a burst pattern for correcting the deviation within one track. A deviation amount for offsetting the write head when switching from a normal data write operation to a normal data read operation so that the center of the core width of the write head matches the burst boundary of the burst pattern It can also be achieved by a burst position deviation data writing method including a step of writing the burst position deviation data by moving the write head to a position offset in the opposite direction by the same offset amount.

  The above-described problem is a magnetic disk device that writes burst position deviation data for correcting a positional deviation of a burst pattern on a magnetic disk, following a burst pattern for correcting a deviation in one track, When the core width of the head is WHD, the interval K between the burst boundaries of the burst pattern, and the number M of areas of the burst misalignment data that need to be provided after the burst pattern, N is an integer of 1 or more. (N-1) When K <WHD <NK, the control means for controlling the position of the write head so that the relationship M = N is established, and the light head whose position is controlled by the control means, This can also be achieved by a magnetic disk device comprising writing means for writing the burst position deviation data on the magnetic disk.

  The above-described problem is a magnetic disk device that writes burst position deviation data for correcting a positional deviation of a burst pattern on a magnetic disk, following a burst pattern for correcting a deviation within one track. The same offset amount as the offset amount for offsetting the write head when switching from the normal data write operation to the normal data read operation so that the center of the core width of the head matches the burst boundary of the burst pattern. And a write means for writing the burst position deviation data onto the magnetic disk by the write head whose position is controlled by the control means. This can also be achieved by a magnetic disk device characterized by the above.

  Therefore, according to the present invention, it is possible to realize a burst position deviation data writing method and a magnetic disk apparatus which can write burst position deviation data of control information onto a magnetic disk so as to be surely readable.

  Embodiments of the burst position deviation data writing method and magnetic disk apparatus according to the present invention will be described below with reference to FIG.

  FIG. 4 is a diagram showing a basic configuration of an embodiment of a magnetic disk apparatus according to the present invention. In this embodiment of the magnetic disk device, the present invention is applied to a hard disk drive (HDD) having a hard disk. In this embodiment of the magnetic disk apparatus, one embodiment of the burst position deviation data writing method according to the present invention is adopted. In the same figure, (b) is a plan view with the upper part of the HDD removed, and (a) is a sectional view taken along (b) the middle line IV-IV.

  As shown in FIG. 4, the HDD 10 generally includes a disk enclosure (DE) 11 and a printed circuit board assembly (PCA) 12. In the DE 11, a hard disk 111, a spindle motor (SPM) 112, a voice coil motor (VCM) 113, an arm 114, a head 115, a ramp mechanism 116, and the like are provided. The disk 111 is rotated in the direction of arrow A by the SPM 112. The VCM 113 moves the head 115 in the radial direction of the disk 111 by rotating the arm 114 in the direction of arrow B, and scans a desired track at the time of seek, for example. The ramp mechanism 116 is disposed outside the disk 111 and is provided to engage the tip of the arm 114 and hold the head 115 away from the disk 111. The head 115 includes a write head and a read head.

  It goes without saying that the basic configuration of the magnetic disk device is not limited to the basic configuration shown in FIG. 4 and various known basic configurations can be adopted. In short, as described later, it is only necessary to have a function of writing the servo position burst position deviation data to the disk 111.

  FIG. 5 is a block diagram showing the configuration of the control system of this embodiment of the magnetic disk device. In the figure, a disk 111, an SPM 112, a VCM 113, a head 115, a head IC 117, and the like are provided in the DE 11. On the other hand, the PCA 12 is provided with a hard disk controller (HDC) 121, a RAM 122, a flash ROM 123, an MPU 124, a read channel (RDC) 125, a servo controller (SVC) 126, drivers 127 and 128, and the like.

  In the DE 11, the head IC 117 performs predetermined processing including amplification processing on the signal read from the disk 111 by the head 115 and then supplies the signal to the RDC 125 in the PCA 12 and also writes (write) supplied from the MPU 124 in the PCA 12. ) A signal is supplied to the head 115 to be written on the disk 111. The VCM 113 drives the arm 114 based on a control signal supplied from the SVC 126 in the PCA 12 via the driver 127. By driving the arm 114, a loading operation for loading the head 115 from the ramp mechanism 116 onto the disk 111 and an unloading operation for unloading the head 115 from the disk 111 onto the ramp mechanism 116 are performed. The SPM 112 rotates the disk 111 based on a control signal supplied from the SVC 126 in the PCA 12 via the driver 128.

  In the PCA 12, the HDC 121 supplies a read / write (read / write) operation instruction to the MPU 124 based on an instruction from the host system 100. The MPU 124 controls the operation of the control system including the SVC 126 based on an instruction from the HDC 121 and a read signal supplied via the RDC 125. The write signal is supplied to the head IC 117 in the DE 11 via the HDC 121 and the MPU 124, and the read signal from the head IC 117 is supplied to the MPU 124 and the HDC 121 via the RDC 125. The read signal supplied to the HDC 121 is supplied to the host system 100. The flash ROM 123 stores various data used when the MPU 124 operates, and the RAM 122 temporarily stores various data used when the MPU 124 and HDC 121 operate.

  Needless to say, the configuration of the control system of the magnetic disk device is not limited to the configuration shown in FIG. 5, and various known configurations can be employed. In short, as described later, it is only necessary to have a function of writing the servo position burst position deviation data to the disk 111.

  FIG. 6 is a diagram for explaining a method of positioning the write head during normal data writing. As shown in FIG. 6, when normal data is written, the read head 34 is on-track to the burst boundary 41 of the burst pattern 31 for correcting the deviation within one track. The burst boundary 41 is a boundary line of the burst pattern 31 along the circumferential direction of the disk 111. At this time, the write head 33 is at a position shifted from the burst boundary 41 by the upward displacement amount d in the radial direction of the disk 111 due to factors such as a shift in yaw (YAW) angle and a shift in the mounting position of the head 111 with respect to the arm 114. . That is, when the center of the target cylinder (or track) coincides with the burst boundary 41, the write head 33 is at a position shifted from the center of the target cylinder by a shift amount d. The shift amount d indicates a shift in the radial direction between the center of the core width of the read head 34 and the center of the core width of the write head 33. Therefore, the write head 33 writes normal data in the area 38 shown by hatching in FIG.

  FIG. 7 is a diagram for explaining the positional relationship between the read head 34 and the write head 33 when reading normal data written in the target cylinder as described above. In the figure, the same parts as those in FIG. As shown in FIG. 7, when reading the normal data written in the target cylinder, the read head 34 is not the center of the target cylinder, but only the radial displacement d of the write head 33 with respect to the read head 34. Move to the offset position and read the data. Such control of the head 111 during normal data writing and reading is well known.

  Next, in this embodiment, the positional relationship between the read head and the write head when writing burst position deviation data will be described with reference to FIG. FIG. 8 is a diagram for explaining the positional relationship between the read head and the write head when writing burst position deviation data in this embodiment. The same parts as those in FIG. .

  As shown in FIG. 8, when writing burst position deviation data, the center of the core width of the write head 33 and the burst boundary 41 need to coincide. That is, when the center of the target cylinder (or track) coincides with the burst boundary 41, the center of the core width of the write head 33 needs to coincide with the center of the target cylinder. Therefore, in this embodiment, when switching from the normal data writing operation as shown in FIG. 6 to the normal data reading operation as shown in FIG. As shown in FIG. 8, the head 33 is moved to a position offset in the reverse direction, and burst position deviation data is written.

  FIG. 9 is a diagram showing the arrangement of burst position deviation data written according to the present embodiment when the feed pitch is 1/2 track. In the figure, a thick solid line indicates a boundary line between adjacent cylinders (or tracks), and a broken line indicates the center of the cylinder (or track). Accordingly, in the figure, the vertical direction corresponds to the radial direction of the magnetic disk, and the horizontal direction corresponds to the circumferential direction of the magnetic disk. Burst position deviation data 32 written following the burst pattern 31 corrects the deviation of the write head 33 from the center of the on-track cylinder and the deviation of the read head 34 from the center of the on-track cylinder. Used for Although not shown, a data area where data is written and read is provided after the burst position deviation data 32 in the circumferential direction of the disk 111.

  The core width 33-CW of the write head 33 is about 75% of the cylinder width 36, and the core width 34-CW of the read head 34 is about 50% of the cylinder width 36. For this reason, an area 35 where no burst position deviation data is written is generated in the position area as indicated by the shaded portion in FIG. When the positional deviation from the target cylinder of the read head 34 immediately after the seek is relatively small, the read head 34 can read the burst position deviation data 32 as in the conventional example described with reference to FIG. Even when the positional deviation of the read head 34 from the target cylinder is relatively large, as shown by P32 in FIG. 9, the read head 34 first scans the area 35 where the burst positional deviation data 32 is not written. However, the subsequent burst position deviation data 32 can be reliably read.

  FIG. 10 is a diagram for explaining the relationship between the burst number and the circumferential position of the disk when writing burst position deviation data. In the figure, the same parts as those in FIG.

  First, the reference burst position is determined. The reference burst position is determined to be, for example, the outermost cylinder, the innermost cylinder, or an arbitrary cylinder of the disk 111. The reference burst position can be determined at an arbitrary burst boundary 41 position. The positional relationship between the burst number, which is the radial position from the reference burst position, and the circumferential position is such that the area of the burst position deviation data 32 is on the scanning direction of the head 111 (opposite to the rotation direction of the disk 111). The number is uniquely determined after the burst pattern 31 is provided. In FIG. 10, for convenience of explanation, when the feed pitch is 1/3 track, the reference burst number 0 is the cylinder number xxx, and there are three areas of the burst position deviation data 32 after the upper burst pattern 31 in the circumferential direction. The case where it is provided is shown.

  FIG. 11 is a flowchart for explaining burst position deviation data reading processing. The process shown in FIG. 5 is executed by the MPU 124 shown in FIG. 5 at the time of calibration, for example, but may be executed together with the HDC 121.

  In FIG. 11, step S1 causes the read head 34 to be on-track to the target burst boundary 41, and step S2 starts detection of burst position deviation data. In step S3, the servo frame number (SF. No. XX) is detected, and in step S4, it is determined whether servo information is detected. If the decision result in the step S4 is NO, the process returns to the step S3. On the other hand, if the decision result in the step S4 is YES, a step S5 detects the current position error signal PESNOW. In step S6, burst position deviation data PES (SF. No. XX) corresponding to the servo frame number (SF. No. XX) is read. In step S7, PES (SF.No.XX) = PES (SF.No.XX) + (PESNOW / SS) is calculated, and the calculation result is stored in the memory means such as the RAM 122 or the ROM 123. In step S8, It is determined whether all servo frames have been completed. Here, SS indicates the specified number of rotations of the disk 111 for calibration.

  If the decision result in the step S8 is NO, a step S9 increments the servo frame number (SF.No.XX) to (SF.No.XX) +1 by 1 and the process returns to the step S5. On the other hand, if the decision result in the step S8 is YES, a step S10 decides whether or not the above series of processing has been completed for the specified number of times SS. If the decision result in the step S10 is NO, a step S11 initializes the servo frame number (SF.No.XX) to 0, and the process returns to the step S5. The process ends if the decision result in the step S10 is YES.

  FIG. 12 is a flowchart for explaining the write processing of burst position deviation data. The processing shown in the figure is executed by the MPU 124 shown in FIG. 5, but may be executed together with the HDC 121.

  In FIG. 12, step S21 sets an activation timer that determines the write start timing of burst position deviation data in the MPU 124. In step S22, when the normal data writing operation as shown in FIG. 6 is switched to the normal data reading operation as shown in FIG. 7, the write head 33 is moved by the same offset amount as the shift amount d for offsetting the write head 33. As shown in FIG. 8, it moves to a position offset in the reverse direction. In step S23, the servo frame number SF. No. XX is detected, and step S24 determines whether a burst pattern of servo information is detected. If the decision result in the step S24 is NO, the process returns to the step S23. On the other hand, if the decision result in the step S24 is YES, a step S25 decides whether or not all burst patterns are completed. If the decision result is YES, the process proceeds to a step S26.

  Step S26 starts the count-down of the activation timer, and step S27 determines whether or not the count-down of the activation timer has ended. If the decision result in the step S27 becomes YES, a step S28 carries out the servo frame number SF. No. The burst position deviation data PES (SF. No. XX) corresponding to XX, which is obtained by calculation, is called from the memory means such as the RAM 122 or the ROM 123. In step S29, the servo position deviation data is written onto the disk 111 by the write head 33 located at the above position, and in step S30, it is determined whether or not all servo frames have been completed. If the decision result in the step S30 is NO, a step S31 increments the servo frame number (SF.No.XX) to (SF.No.XX) +1 by 1 and the process returns to the step S23. On the other hand, the process ends if the decision result in the step S30 is YES.

  The burst position deviation data writing process as shown in FIG. 12 is performed by a servo track writer (STW: Servo Track Writer) dedicated to servo information writing, and is written in advance on the magnetic disk 111 together with the servo information. Needless to say, good things.

  Next, from the relationship between the core width 33-CW of the write head 33 and the feed pitch, the number of areas of the burst position deviation data 32 that should be provided after the upper burst pattern 31 in the circumferential direction will be described with reference to FIG. explain. When the value of the core width 33-CW of the write head 33 is represented by WHD and the interval between the burst boundaries 41 is represented by K, burst position deviation data 32 that needs to be provided after the WHD, K and the upper burst pattern 31 in the circumferential direction of the disk 111 The following relationship holds between the number M of the regions.

          (1) When WHD <K, M = 1.

          (2) If K <WHD <2K, M = 2.

          (3) If 2K <WHD <3K, M = 3.

(4) When 3K <WHD <4K, M = 4.
Therefore, when N is an integer of 1 or more, the following relationship is established.

          (5) (N-1) When K <WHD <NK, M = N.

  FIG. 13 is a diagram showing a writing state of the burst position deviation data 32 on the disk 111 in the cases (1), (2) and (3). In the figure, (a) shows the case of (1) above, (b) shows the case of M = 1 at the top and the case of (2) above, (c) shows M = 1 and The case of M = 2 is shown in the upper part and the middle part, and the case of the above (3) is shown in the lower part. In the figure, the same parts as those in FIG.

  As can be seen from FIG. 13 (b), in the case of (2) above, by dividing the area of the burst misalignment data 32 into two areas, an area overlapping in the radial direction as shown by the shaded portion is generated. Can be avoided. In addition, as can be seen from FIG. 13C, in the case of (3) above, the area of the burst position deviation data 32 is divided into three areas, thereby overlapping the areas in the radial direction as shown by the shaded portions. Can be avoided.

  Therefore, by satisfying the relationship (5), there is no area where the burst position deviation data 32 is not written in the scanning direction along the circumferential direction of the disk 111 of the read head 34. Even when the center of the core width of the read head 34 is shifted from the center of the cylinder at the end of seeking, the burst position shift data 32 can be read reliably. Further, since there is no region where the burst position deviation data 32 overlaps in the radial direction of the disk 111, the burst position deviation data 32 can be read correctly.

  The present invention includes the inventions appended below.

(Supplementary note 1) A burst position deviation data writing method for writing burst position deviation data for correcting positional deviation of a burst pattern on a magnetic disk following a burst pattern for correcting deviation within one track. ,
When N is an integer greater than or equal to the core width of the write head, WHD, the interval K between the burst boundaries of the burst pattern, and the number M of the burst misalignment data areas that need to be provided after the burst pattern (N-1) A burst position deviation data writing method including a step of writing the burst position deviation data so that a relationship of M = N is established when K <WHD <NK.

(Supplementary Note 2) A burst position deviation data writing method for writing burst position deviation data for correcting positional deviation of a burst pattern on a magnetic disk following a burst pattern for correcting deviation within one track. ,
The same offset as the amount of offset for offsetting the write head when switching from normal data write operation to normal data read operation so that the center of the core width of the write head matches the burst boundary of the burst pattern A method for writing burst position deviation data, comprising: writing the burst position deviation data by moving the write head to a position offset in the opposite direction by an amount.

    (Supplementary Note 3) When the center of the target cylinder on the magnetic disk coincides with the burst boundary, the step makes the center of the core width of the write head coincide with the center of the target cylinder. Supplementary note 2) Burst position deviation data writing method.

    (Supplementary Note 4) The burst position deviation data writing method according to any one of (Appendix 1) to (Supplementary Note 3), wherein the step is performed during calibration of the magnetic disk device.

    (Additional remark 5) The said step is performed by the servo track writer (STW) only for servo information writing, The writing method of the burst position shift data of any one of (Appendix 1)-(Appendix 3) .

    (Supplementary Note 6) N is 1 or more among the core width of the write head as WHD, the interval K between the burst boundaries of the burst pattern, and the number M of areas of the burst misalignment data that need to be provided after the burst pattern In the case where (N−1) K <WHD <NK, the step writes the burst position deviation data so that the relationship M = N is established (Appendix 2) to The burst position deviation data writing method according to any one of (Appendix 5).

(Supplementary note 7) A magnetic disk device for writing burst position deviation data for correcting a positional deviation of the burst pattern on a magnetic disk following a burst pattern for correcting a deviation within one track,
When N is an integer greater than or equal to the core width of the write head, WHD, the interval K between the burst boundaries of the burst pattern, and the number M of the burst misalignment data areas that need to be provided after the burst pattern , (N-1) When K <WHD <NK, control means for controlling the position of the write head so that the relationship M = N is established;
A magnetic disk apparatus comprising: writing means for writing the burst position deviation data onto the magnetic disk by the write head whose position is controlled by the control means.

(Supplementary Note 8) A magnetic disk device for writing burst position deviation data for correcting a positional deviation of the burst pattern on a magnetic disk following a burst pattern for correcting a deviation in one track,
The same offset as the amount of offset for offsetting the write head when switching from normal data write operation to normal data read operation so that the center of the core width of the write head matches the burst boundary of the burst pattern A control means for moving the light head to a position offset in the reverse direction by an amount;
A magnetic disk apparatus comprising: writing means for writing the burst position deviation data onto the magnetic disk by the write head whose position is controlled by the control means.

    (Supplementary Note 9) When the center of the target cylinder on the magnetic disk coincides with the burst boundary, the control unit adjusts the center of the core width of the write head so as to coincide with the center of the target cylinder. The magnetic disk device according to (Appendix 8), wherein the position is controlled.

    (Supplementary Note 10) The magnetic disk device according to any one of (Appendix 7) to (Appendix 9), wherein the writing unit writes the burst position deviation data during calibration of the magnetic disk device. .

    (Appendix 11) The magnetic disk device according to any one of (Appendix 7) to (Appendix 10), wherein a core width of the write head is smaller than a core width of the read head.

  As mentioned above, although this invention was demonstrated by the Example, this invention is not limited to the said Example, It cannot be overemphasized that various deformation | transformation and improvement are possible.

It is a figure explaining a servo frame format. It is a figure which shows arrangement | positioning of the burst position shift data written by the conventional burst position shift data writing method. It is a figure which shows arrangement | positioning of the burst position shift data written by the possible burst position shift data writing method. It is a figure which shows the basic composition of one Example of the magnetic disc apparatus which becomes this invention. It is a block diagram which shows the structure of the control system of the Example of a magnetic disc apparatus. It is a figure explaining the positioning method of the write head at the time of normal data writing. It is a figure explaining the positional relationship of the read head and write head at the time of reading the normal data written in the target cylinder. It is a figure explaining the positional relationship of the read head at the time of writing burst position shift data. It is a figure which shows arrangement | positioning of the burst position shift data written by the Example. It is a figure explaining the relationship between the burst number at the time of the writing of burst position shift data, and the circumferential direction position of a disk. It is a flowchart explaining the reading process of burst position shift data. It is a flowchart explaining the write processing of burst position shift data. It is a figure which shows the write state of the burst position shift data on a disk.

Explanation of symbols

10 HDD
33 Write head 34 Read head 41 Burst boundary 111 Magnetic disk 115 Head 121 HDC
124 MPU

Claims (5)

A burst position deviation data writing method for writing burst position deviation data for correcting a positional deviation of the burst pattern on a magnetic disk following a burst pattern for correcting a deviation in one track,
The same offset as the amount of offset for offsetting the write head when switching from normal data write operation to normal data read operation so that the center of the core width of the write head matches the burst boundary of the burst pattern A method for writing burst position deviation data, comprising: writing the burst position deviation data by moving the write head to a position offset in the opposite direction by an amount.   2. The method according to claim 1, wherein when the center of the target cylinder on the magnetic disk coincides with the burst boundary, the step makes the center of the core width of the write head coincide with the center of the target cylinder. How to write burst position deviation data.   4. The burst position deviation data writing method according to claim 1, wherein the step is performed during calibration of the magnetic disk device. A magnetic disk device for writing burst position deviation data for correcting a positional deviation of a burst pattern on a magnetic disk following a burst pattern for correcting a deviation in one track,
The same offset as the amount of offset for offsetting the write head when switching from normal data write operation to normal data read operation so that the center of the core width of the write head matches the burst boundary of the burst pattern A control means for moving the light head to a position offset in the reverse direction by an amount;
A magnetic disk apparatus comprising: writing means for writing the burst position deviation data onto the magnetic disk by the write head whose position is controlled by the control means. 5. The magnetic disk drive according to claim 4, wherein the core width of the write head is smaller than the core width of the read head.

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