JP4227111B2 - Servo information writing method - Google Patents

Description

  The present invention relates to a servo information writing method for writing servo information of a disk device onto a disk medium, and more particularly to a servo information writing method using a bank write method in a self-servo writing of a magnetic disk device.

  2. Description of the Related Art In recent years, a magnetic disk device typified by a hard disk drive (hereinafter sometimes referred to as a disk drive) has servo information (used for head positioning control) on a disk medium used as a data recording medium. Servo pattern) is recorded.

  In a disk drive manufacturing process, a servo writing process for recording servo information on a disk medium is one of the important processes affecting the efficiency of the entire manufacturing process. For this reason, various servo writing methods have been proposed or developed in order to improve efficiency. Among these methods, attention is focused on a magnetic transfer method in which servo information is transferred from a disk serving as a master disk onto a disk medium incorporated in a disk drive and recorded.

  By the way, the transfer source servo information (hereinafter referred to as original servo information) recorded on the master disc is distorted due to, for example, an attachment error when the master disc is attached to the original servo information writing device. there is a possibility.

  Also, in the manufacturing process of the disk drive, when the disk medium is incorporated in the drive, the disk medium may be decentered due to an assembly error or the like. For this reason, in the disk drive, when head positioning control is executed using the original servo information transferred onto the disk medium as it is, positioning errors due to distortion of the original servo information and disk eccentricity of the disk medium are not detected. It is likely to occur.

  Therefore, a method has been proposed in which the disk eccentricity is measured for each disk medium on which servo information is recorded, and the disk eccentricity is recorded on the disk medium as positioning correction information (see, for example, Patent Document 1). .

  In addition, a plurality of, for example, two disk media are stacked and fixed on a spindle motor hub in a disk drive, and a magnetic head is often disposed facing the front and back surfaces of each disk medium. In such a disk drive mounted with a plurality of disk media, the disk media flutters in the motor axial direction due to an error in mounting the disk media to the hub as the disk media is rotated by the spindle motor. May be referred to as disk flutter hereinafter).

At this time, since there is a characteristic in the direction of displacement of the two disk media by the disk flutter, it is desired to propose a servo information writing method in consideration of this displacement direction.
Japanese Patent No. 3295940 (FIG. 1, claims)

  However, these prior arts are methods for generating positioning correction information after measuring the disk eccentricity (resulting in distortion of servo information) for each disk medium, and recording the information on the disk medium. The time required for the servo writing process is increased by the time required for generating the correction information. In addition, a servo information writing method that takes into account displacement due to disk flutter of a plurality of stacked disk media has not been proposed, and these have been desired.

  Accordingly, the present invention has been made to solve the above-described problem. By considering a disk flutter and appropriately selecting a surface for bank write servo track write (STW), the servo track write (STW) is performed. It is an object of the present invention to provide a servo information writing method capable of improving accuracy.

  In order to solve the above-described problem, the servo information writing method according to the present invention, and the second surface of the first disk medium and the first of the second disk medium among the plurality of disk media each having a plurality of surfaces. A servo information writing method for writing servo information used for head positioning control on the first and second disk media of an incorporated disk drive arranged so that the surfaces of the disk drives face each other. A step of executing positioning control of a head included in the disk drive based on original servo information recorded on the first surface of one disk medium, and positioning for correcting a positioning error by the positioning control; A step of generating correction information, and a step of recording the positioning correction information in a storage means provided outside the disk drive. And obtaining the positioning correction information, and simultaneously applying new servo information on the first surface of the first disk medium and the second surface of the second disk medium incorporated in the disk drive. And a writing step.

  According to the present invention, the servo track write (STW) accuracy is improved by taking the disk flutter into consideration and appropriately selecting the bank write type servo track write (STW) surface. It is possible to provide a servo information writing method that can be improved.

Hereinafter, a magnetic disk device, a so-called hard disk drive (hereinafter referred to as HDD) will be described in detail as a disk device according to an embodiment of the present invention with reference to the drawings.
FIG. 1A shows an HDD 1 according to this embodiment. In the HDD 1, data is recorded / reproduced with respect to the disk medium 2 by using a head which is a recording / reproducing element 4 with respect to the disk medium 2 rotated by the spindle motor 3. The movement of the recording / reproducing element 4 is driven by a voice coil motor 6 via an arm 5. The recording / reproducing element 4 is supported by an arm 5 so as to float on the surface of the disk medium 2 and move. The magnetic force generated by the voice coil motor 6 causes the recording / reproducing element 4 to move to the disk medium 2. It is movable in the radial direction.

Next, details of the HDD 1 according to the present embodiment will be described with reference to FIG. FIG. 1B shows a side view of the HDD 1 shown in FIG.
In the HDD 1 of the present embodiment, two disk media 2 are stacked and mounted at a predetermined interval with a spacer or the like on the axis of the spindle motor 3. Of the two disk media 2 stacked on the spindle motor 3, the disk medium 21 attached to the upper part, that is, the cover side of the apparatus is referred to as a first disk medium 21, and the lower part, that is, the base casing side of the apparatus. The disk medium 22 attached to is referred to as a second disk medium 22. These have a structure in which the first and second disk media 21 and 22 can be simultaneously rotated integrally by the spindle motor 3.

  The first disk medium 21 has an upper surface 21a (first surface 21a) and a lower surface (second surface 21b), and the second disk medium 22 is also the first disk medium 21. Similarly, the upper surface 22a (first surface 22a) and the lower surface (second surface 22b) are provided, and the lower surface 21b (second surface) of the first disk medium 21 is provided. The first disk medium 21 and the second disk medium 22 are stacked on the shaft of the spindle motor 3 so that the surface 21b) and the upper surface 22a (first surface 22a) of the second disk medium 22 face each other. ing.

  Further, one recording / reproducing element 4 is arranged to face each disk surface (21a, 21b, 22a, 22b) of each of the disk media 21, 22, respectively. That is, the first recording / reproducing element 4a faces the first surface 21a of the first disk medium 21 and the second recording / reproducing element 4b faces the second surface 21b of the first disk medium 21. However, the third recording / reproducing element 4c faces the first surface 22a of the second disk medium 22 and the recording of the fourth recording medium faces the second surface 22b of the second disk medium 22. Reproducing heads 4d are respectively arranged so as to face each other, and these recording / reproducing elements 4a to 4d are respectively attached to a plurality of arms 5 (5a to 5d) stacked and mounted on a shaft attached to the base casing.

  Furthermore, the only voice coil motor 6 is provided on the side opposite to the recording / reproducing elements 4a to 4d of the arms 5a to 5d with the axis as the center, and the recording / reproducing element 4 is driven by the voice coil motor 6, It is possible to move while flying in the radial direction on the disk medium 2. That is, the recording / reproducing elements 4a to 4d facing the recording surfaces 21a, 21b, 22a and 22b of the respective disk media 21 and 22 are moved together and guided to substantially the same radial position on the surface of the disk medium 2. .

Next, the self-running self-supporting servo write method will be described with reference to FIG. 2 (FIGS. 2A to 2B).
FIG. 2 shows a servo pattern in the self-propelled self-supporting servo light. First, as shown by 201 in FIG. 2A, a servo pattern 203 is written in advance on a part of the inner periphery of the surface of the disk medium 2, and the head 4 is positioned by this servo pattern 203 while the disk medium 2 is positioned radially outward. The servo write is realized by adding a new servo pattern 204 to (Fig. 2B) 202.

  In the middle of servo writing, the recording / reproducing element 4 is positioned by the servo pattern 204 written by itself, and further servo patterns 204 are successively added to the outside of the disk medium 2 in the radial direction. In the present embodiment, the first original servo pattern 203 uses a medium written in advance before being mounted on the HDD using an external device. However, the original servo pattern 203 itself is also written by itself. There is also.

Next, the rewritable self-supporting servo write method will be described with reference to FIG. 3 (FIGS. 3A to 3C).
FIG. 3 shows a servo pattern in the rewritable self-supporting servo light. As shown in FIG. 3A, in this embodiment, first, the servo pattern 301 (master pattern 301) is written over the entire surface only on one specific surface (the first surface 21a of the first disk medium 21). As shown in FIG. 3B, the recording / reproducing element 4 is positioned on the master servo pattern 301 and the servo pattern 302 is copied.

  Two or more recording / reproducing elements 4 (two surfaces), for example, as in the present embodiment, the first surface 21a, the second surface 21b of the first disk medium 21 and the first of the second disk medium 22 are used. In the case of the HDD 1 mounted so as to face the second surface 22a and the second surface 22b, by using a bank write described later, as shown in FIG. 3C, the first master pattern 301 is not applied. Servo patterns 303a and 303b can be written on the second surface 21b of the disk medium 21 and the first and second surfaces (22a and 22b) of the second disk medium 22.

Next, the bank write operation will be described with reference to FIG.
When recording / reproducing user data on the HDD 1, it is only necessary to consider recording / reproducing on a specific surface. On the other hand, when writing servo patterns, it is considered to write simultaneously to all heads (surfaces) in order to shorten the writing time.

  That is, first, the recording / reproducing element 4a is positioned on the medium on which the master pattern 401 is written over the entire surface of one specific surface (the first surface 21a of the first disk medium 21). Next, with the recording / reproducing element 4a positioned, the first surface 21a, the second surface 21b, the first surface 22a, and the second surface 22b of the second disk medium 22 are placed on the first disk medium 21. The servo patterns 402 and 403 are written simultaneously at the same time on the respective surfaces by the recording heads of the recording / reproducing elements 4a to 4d facing each other.

Next, the operation of the staggered write will be described with reference to FIG.
The above-mentioned servo write method that does not use bank write is a means for shortening the servo write time and is called a staggered write method. In the example of the self-supporting servo write, the information is read out by the recording / reproducing element 4 using the servo pattern 501 (master servo pattern 501) used for positioning, and immediately after that, the first disk medium 21 of the first disk medium 21 is read. The servo pattern 502 is written on the surface 21a. Immediately after writing the servo pattern 502 on the first surface 21a of the first disk medium 21, the writing surface is switched to the second surface 21b and the servo pattern 503 is written.

  Thereafter, the recording surface is sequentially switched from 21b to 22a and from 22a to 22b, and servo patterns are written on the surface in accordance with this switching. That is, immediately after writing the servo pattern 502, the writing surface is switched to the first surface 22a of the second disk medium 22, the servo pattern 504 is written, and immediately after the servo pattern 504 is written, the writing surface is changed to the first surface 22a. The servo pattern 505 is written by switching to the second surface 22b of the second disk medium 22.

  At this time, the servo write operation is performed on all surfaces until the next servo information used for positioning is read. By performing the above operation on all servo sectors, writing of servo patterns on all surfaces in a certain cylinder can be realized.

In the present embodiment, the staggered write and the bank write described above can be used without distinction as a write method that performs the same operation.
<Banklight rules>
Next, the vertical vibration (hereinafter referred to as disk flutter) of the disk medium 2 in the HDD 1 and the bank write rule will be described with reference to FIG.
FIG. 6 shows the influence on the positioning accuracy by the disk flutter and the disk flutter. The disk flutter is a mechanism vibration in which the disk medium 21 vibrates up and down with the center of the rotation axis of the hub of the spindle motor 3 as a fulcrum. In this embodiment, the state of the disk medium 21 and the recording / reproducing element 4 when the disk flutter is not occurring is shown in FIG. 6A, and the state of the disk medium 21 and the recording / reproducing element 4 when the disk flutter is occurring is shown. As shown in FIG.

  When this disk flutter occurs (FIG. 6B), the recording / reproducing elements 4a and 4b attached to the arms 5a and 5b are maintained parallel to the disk medium 21, so that the disk medium 21 When oscillating toward the recording / reproducing elements 4a, 4b, the recording / reproducing elements 4a, 4b vibrate in a direction that the disk medium 21 moves away from the recording / reproducing elements 4a, 4b outside the radial direction of the disk medium 21. In some cases, the recording / reproducing elements 4 a and 4 b move inward in the radial direction of the disk medium 21.

  Here, two recording / reproducing elements 4a and 4b are attached to one disk medium 21 so as to sandwich the respective surfaces (first surface 21a and second surface 21b) of the disk medium 21. It can be confirmed that the positioning disturbance due to the disk flutter is a disturbance in the opposite phase at the top and bottom of the recording / reproducing element 4, that is, the recording / reproducing elements 4a and 4b.

  In a self-supporting servo writer that positions the recording / reproducing element 4 on a specific track using the servo pattern written on the disk medium 21 and writes the servo pattern on a track different from the track, the disk flutter disturbance is suppressed. When such a positioning control system is constructed, it can be confirmed that the disk flutter disturbance on the surface opposite to the surface used for positioning of the disk medium 21 used for positioning is doubled. For example, in this embodiment, when the surface used for positioning of the disk medium 21 used for positioning is the first surface 21a, the recording / reproducing element by the disk flutter on the opposite surface 21b side is used. On the contrary, the disturbance to 4a and 4b is doubled.

  For this reason, when bank writing is performed in a self-supporting servo writer, servo patterns are written simultaneously (at a time) on the front and back of a certain disk medium 21, that is, when bank writing is performed, the servo write accuracy on one side is deteriorated. . For this reason, in the self-supporting servo write, the maximum number of surfaces that can be bank-written is one for one disk storage medium.

  However, in an HDD having only one disk medium, applying the bank write rule described above is the same procedure as servo writing that contributes to shortening the servo pattern writing time.

<Bank write rules for magnetic disks with multiple media>
Next, disk flutter and bank write rules for the disk media 21 and 22 when a plurality of disk media (21 and 22) are mounted on the HDD 1 will be described with reference to FIG.

  FIG. 7 shows the state of disk flutter in an HDD having two disk media (21, 22). When there are two disk media (21, 22), the disk flutter vibrates in plane symmetry in the respective disk media 21, 22. That is, when the upper disk medium 21 (first disk medium 21) vibrates upward, the lower disk medium 22 (second disk medium 22) vibrates downward. 6, the recording / reproducing element 4b facing the lower surface 21b (second surface 21b) of the upper disk medium 21 (first disk medium 21) and the lower disk medium 22 (first disk medium 21) are used. 2 shows that the recording / reproducing element 4c facing the upper surface 22a (first surface 22a) of the second disk medium 22) vibrates in the same direction, that is, in the radial direction of the disk medium 2 in the same phase.

  Therefore, in an HDD having two disk media 2 (21, 22), the recording / reproducing element 4b facing the lower surface 21b (second surface 21b) of the upper disk medium 21 (first disk medium 21). The selected disk write is performed with the recording / reproducing element 4c facing the upper surface 22a (first surface 22a) of the lower disk medium 22 (second disk medium 22) as the first set, and the upper disk medium The recording / reproducing element 4a facing the upper surface 21a (first surface 21a) of the 21 (first disk medium 21) and the lower surface 22b of the lower disk medium 22 (second disk medium 22) ( By performing the selected bank write with the recording / reproducing element 4d facing the second surface 22b) as the second set, it is possible to realize a servo write that is not affected by the disk flutter.

  Even in the case where there are three or more disk media 2, as in the above-described embodiment, the recording and reproducing elements (surfaces) in which the vibration phases (in some cases, the amplitudes) of the disk flutter are substantially the same are combined, By writing the servo pattern to the disk medium by bank writing, it is possible to realize a servo write that is not affected by disk flutter.

<Design method of positioning control system for independent servo write using selected bank write>
Next, a flowchart of a method for writing a servo pattern by the bank write method by selecting a writing surface according to the present embodiment will be described with reference to FIGS. That is, a self-serving servo write procedure when using the selected bank write in this embodiment will be described with reference to a flowchart.

  First, in FIG. 8A, the positioning control of the recording / reproducing element 4 is performed using one of the specific surfaces of the disk medium bank-written by the selected bank write, and the bank set by the selected bank write is executed. This procedure is repeated for the number of light groups. That is, this is a procedure for changing the positioning surface.

  First, servo writing is started (S1a), and then positioning is performed by the recording / reproducing element 4a (with the head 0) to suppress disk flutter, and the surfaces of the recording / reproducing elements 4a, 4d (heads 0, 3) Servo writing is executed (S2a). Next, the recording / reproducing element 4b (with the head 1) is positioned, the disk flutter is suppressed, and servo writing is performed on the surfaces (heads 1 and 2) of the recording / reproducing elements 4b and 4c (S3a). Then, the servo write is finished (S4a).

  In this case, since the positioning control of the recording / reproducing element 4 suppresses the disk flutter and the positioning control design becomes easy, the servo write accuracy can be easily increased.

  Next, in FIG. 8B, the recording / reproducing element 4 is positioned and controlled on a specific surface regardless of the bank writing surface. That is, this is a procedure for changing the positioning control characteristics.

  First, servo writing is started (S1b), and then positioning is performed by the recording / reproducing element 4a (with the head 0) to suppress disk flutter, and the surfaces of the recording / reproducing elements 4a, 4d (heads 0, 3) Servo writing is executed (S2b). Next, the recording / reproducing element 4a (with the head 0) is positioned, the disk flutter is amplified, and servo writing is performed on the surfaces (heads 1 and 2) of the recording / reproducing elements 4b and 4c (S3b). Then, the servo write is finished (S4b).

  At this time, when positioning control is performed on a surface that is not servo-written by the selected bank write, in consideration of the disc flutter disturbance generation principle shown in FIG. 6, it is amplified twice without changing the phase of the disc flutter disturbance. A positioning control system will be designed. In this case, the servo pattern shape learning time is shortened, but it is necessary to design two or more types of head positioning control systems.

  As described in each of the above-described embodiments, in the independent servo write in the HDD in which two or more (a plurality of) disk media are mounted, the selected bank write is performed twice or more, thereby reducing the servo write time. While shortening, it becomes possible to prevent deterioration of servo write accuracy due to disturbance of disk flutter.

  According to the disk device configured as described above, it is possible to improve servo track write (STW) accuracy by appropriately selecting a bank write type servo track write (STW) surface in consideration of disk flutter. Therefore, it is possible to provide a servo information writing method capable of performing the above.

Schematic (A) and side view (B) of HDD according to this embodiment of the present invention The conceptual diagram of the self-propelled self-supporting servo write method concerning this embodiment of the present invention Conceptual diagram of a rewritable self-supporting servo write method according to the present embodiment of the present invention The conceptual diagram explaining operation | movement of the bank write system which concerns on this embodiment of this invention. The conceptual diagram explaining operation | movement of the staggered system which concerns on this embodiment of this invention. Explanatory diagram regarding disk flutter and bank write rules in the HDD according to the present embodiment Explanatory drawing regarding a disk flutter and bank write rules when a plurality of disk media are mounted in the HDD according to the present embodiment Flowchart of servo pattern writing method according to this embodiment of the present invention

Explanation of symbols

1 …… HDD
2... Disk medium 3... Spindle motor 4... Recording / reproducing element 5... Arm 6... Voice coil motor 21... First disk medium 22. First surface 21b of the first disk medium Second surface 22a of the first disk medium Second surface of the second disk medium 22b Second surface of the second disk medium 203 Master pattern 204 ... Servo pattern 301 ... Master servo pattern 302, 303 ... Servo pattern 401 ... Master servo pattern 302, 403 ... Servo pattern 501 ... Master servo pattern 502, 503, 504, 505 ... Servo pattern

Claims (6)

Among the plurality of disk media each having a plurality of surfaces, the first of the built-in disk drives arranged so that the second surface of the first disk medium and the first surface of the second disk medium face each other. A servo information writing method for writing servo information used for head positioning control on first and second disk media,
Executing positioning control of a head included in the disk drive based on original servo information recorded on the first surface of the first disk medium;
Generating positioning correction information for correcting positioning error by the positioning control;
Recording the positioning correction information in a storage means provided outside the disk drive;
Acquiring the positioning correction information and simultaneously writing new servo information on the first surface of the first disk medium and the second surface of the second disk medium incorporated in the disk drive; ,
A servo information writing method for executing a procedure having: Executing positioning control of a head included in the disk drive based on servo information recorded on the second surface of the first disk medium;
Generating positioning correction information for correcting positioning error by the positioning control;
Recording the positioning correction information in a storage means provided outside the disk drive;
Acquiring the positioning correction information and simultaneously writing new servo information on the second surface of the first disk medium incorporated in the disk drive and the first surface of the second disk medium; ,
The servo information writing method according to claim 1, further comprising: Executing positioning control of a head included in the disk drive based on servo information recorded on the first surface of the first disk medium;
Generating positioning correction information for correcting positioning error by the positioning control;
Recording the positioning correction information in a storage means provided outside the disk drive;
Acquiring the positioning correction information and simultaneously writing new servo information on the second surface of the first disk medium incorporated in the disk drive and the first surface of the second disk medium; ,
The servo information writing method according to claim 1, further comprising: Following the step of performing positioning control of the head included in the disk drive based on the original servo information recorded on the first surface of the first disk medium,
Suppressing disk flutter of the plurality of disk media;
The servo information writing method according to claim 1, further comprising: Following the step of performing positioning control of the head included in the disk drive based on the servo information recorded on the second surface of the first disk medium.
Suppressing disk flutter of the plurality of disk media;
The servo information writing method according to claim 2, further comprising: Following the step of performing positioning control of a head included in the disk drive based on servo information recorded on the first surface of the first disk medium.
Amplifying disk flutter of the plurality of disk media;
The servo information writing method according to claim 3, further comprising:

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