JP4909828B2 - Magnetic disk device and magnetic disk recording control method - Google Patents

Description

The present invention relates to a magnetic disk apparatus having a magnetic disk such as a so-called discrete track medium, and a magnetic disk recording control method.

  A conventional magnetic disk device is disclosed in Patent Document 1. The magnetic disk device disclosed in this document includes a magnetic disk suitable for a perpendicular magnetic recording system such as a discrete track medium. A magnetic disk has a plurality of magnetic bands (data areas) in which recording tracks are formed by a magnetic head, a nonmagnetic band (nonmagnetic portion) that delimits these magnetic bands, and adjacent to the ends of these magnetic bands and nonmagnetic bands. Servo area for tracking. At the time of recording, the servo area is read by the magnetic head, the center position in the width direction of each magnetic band is specified, and writing control is performed with the magnetic head aligned with the center position in the width direction. As a result, a recording track is formed in each magnetic band by one row.

JP 2006-48751 A

  However, in the above conventional magnetic disk device, there is a manufacturing limit on the head processing width of the magnetic head, and the magnetic disk itself has a manufacturing limit on the width of the magnetic band and the non-magnetic band. In the method of forming recording tracks one row at a time, the track pitch can only be narrowed to a certain limit, and as a result, there is a problem that a high recording density cannot be sufficiently achieved.

The present invention has been conceived under the circumstances described above. The present invention can be narrowed as much as possible the track pitch, and its object is to provide a turn high recording density magnetic disk apparatus that can be achieved a sufficient, and a magnetic disk recording control method.

  In order to solve the above problems, the present invention takes the following technical means.

A magnetic disk device provided by the first aspect of the present invention includes a magnetic head and a plurality of magnetic bands on which recording tracks for recording information by the magnetic head are formed, and a non-magnetic section that separates these magnetic bands. A magnetic disk device comprising a magnetic disk having a magnetic band and a tracking servo pattern area adjacent to the ends of the magnetic band and the non-magnetic band, and by reading the servo pattern area with the magnetic head, The center position in the width direction of each magnetic band is specified, and an offset position specifying means for specifying a plurality of offset positions deviated from the center position in the width direction by a predetermined amount in the disk radial direction, and the magnetic head at each offset position By performing recording control in the aligned state, at least the inside and outside of the disk radial direction are placed on each magnetic band It is characterized by having a recording control means for forming the recording tracks of the two columns with.

  Preferably, the recording control means forms a recording track while taking a margin of a predetermined width between the plurality of recording tracks in each magnetic band region.

A magnetic disk recording control method provided by the second aspect of the present invention includes a plurality of magnetic bands in which recording tracks are formed by a magnetic head, a non-magnetic band that divides these magnetic bands, and these magnetic bands and non-magnetic bands. A magnetic disk recording control method for forming the recording track by recording control on a magnetic disk having a tracking servo pattern area adjacent to an end of a band, wherein the servo pattern area is read by the magnetic head Thus, the center position in the width direction of each magnetic band is specified, and an offset position specifying step for specifying a plurality of offset positions shifted from the center position in the width direction by a predetermined amount in the disk radial direction; and By performing recording control with the magnetic head aligned, at least two magnetic bands are provided. It is characterized by sequentially executing a recording control step of forming the recording track of the min.

  According to such a configuration, since, for example, two rows of recording tracks can be formed in each magnetic band, the track pitch can be further narrowed, and the recording density can be sufficiently increased.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 4 show an embodiment of a magnetic disk device according to the present invention. As shown in FIG. 1, the magnetic disk device A includes a magnetic disk X called a so-called discrete track medium. In addition to a plurality of magnetic disks X, the magnetic disk device A includes a magnetic head 1, a spindle motor 2, a swing arm 3, an actuator 4, and a disk controller 5.

  The plurality of magnetic disks X are stacked one above the other with a predetermined interval, and both front and back surfaces of each magnetic disk X are used as recording surfaces. The magnetic head 1 reads / writes data from / to the magnetic disk X, and is provided at the tip of each swing arm 3 so as to face the recording surface of the magnetic disk X. The spindle motor 2 rotates the magnetic disk X at high speed. The swing arm 3 reciprocates the magnetic head 1 in the substantially radial direction of the magnetic disk X, and is quickly operated by the actuator 4. The actuator 4 is composed of a voice coil motor or the like. The disk controller 5 controls the magnetic head 1, the spindle motor 2, and the actuator 4, and is composed of a microcomputer having a CPU, a memory, etc., or a wired logic circuit having a function equivalent to the microcomputer. . As shown in FIG. 3, as a function of the disk controller 5, a rotation control unit 50, a seek operation control unit 51, a tracking control unit 52, and a recording / reproduction control unit 53 are provided.

  As shown in FIG. 1 with the surface partially enlarged, the magnetic disk X is divided into a plurality of magnetic bands 10 in which recording tracks are formed by the magnetic head 1 during recording, and these magnetic bands 10 are divided in the disk radial direction. It has a nonmagnetic band 11 and a servo pattern area S for tracking adjacent to the end of the magnetic band 10 and the nonmagnetic band 11. The magnetic band 10 and the nonmagnetic band 11 are formed to be concentric along the circumferential direction of the disk. As the magnetic disk, a so-called bit pattern medium in which a portion corresponding to a magnetic band is periodically divided into a magnetic part and a non-magnetic part along the disk circumferential direction may be applied.

  As shown in FIG. 2, the magnetic band 10 has a width that allows two recording tracks T to be formed as an example. A detrack margin M that does not affect recording / reproduction is formed between the two recording tracks T formed in each magnetic band 10 so as to have a predetermined width. In the servo pattern region S, a plurality of reading cells Sa to Sd composed of unit sections are regularly arranged. Each of the reading cells Sa to Sd has a width corresponding to the head width of the magnetic head 1 and is formed so as to form a regular pattern of fine magnetic portions and nonmagnetic portions although not particularly shown. These read cells Sa to Sd form the same type of servo pattern for each column along the disk radial direction. Such a servo pattern region S is arranged so as to divide the nonmagnetic band 11 extending in the circumferential direction of the disk in some places. The magnetic disk X is manufactured so that the width of the reading cells Sa to Sd and the nonmagnetic band 11 is about several tens of nanometers by ultrafine processing such as electron beam lithography, nanoimprint using a stamper, and dry etching. 2, the head width of the magnetic head 1 is Wh, the width of each recording track T formed on the magnetic band 10 is Wnn, and the width of the non-magnetic band 11 (hereinafter referred to as “discrete width”). Wg, and the width of the detrack margin M is Wm. Since two recording tracks T are formed in one magnetic band 10, the average track pitch Tp is equal to the separation distance between the magnetic band 10 and the nonmagnetic band 11.

  The disk access process for recording / reproducing with respect to the magnetic disk X is performed as follows.

  As shown in FIG. 4, first, the rotation control unit 50 of the disk controller 5 makes the magnetic disk X rotate at a high speed. In this state, the seek operation control unit 51 passes the servo pattern region S via the magnetic head 1. The track address for sparse adjustment written in advance in a different area is read out. Thus, the magnetic head 1 is adjusted to the magnetic band 10 to be recorded or reproduced by the seek operation (S1).

  Next, the tracking control unit 51 reads the servo pattern area S for fine adjustment via the magnetic head 1 to identify the center position C0 in the width direction of the target magnetic band 10. Furthermore, the tracking control unit 51 specifies offset positions C1 and C2 that are shifted from each other by a predetermined amount from the center position C0 in the width direction of the magnetic band 10. The offset positions C1 and C2 coincide with the central axis of the recording track T. For example, when the magnetic head 1 is positioned at the center of the reading cell Sc as shown in FIG. 2, a burst signal Vc having a large amplitude corresponding to the reading cell Sc is obtained, while depending on the other reading cells Sa and Sb. Burst signals Va and Vb having small amplitudes are obtained. By calculating these burst signals Va and Vb, a servo signal Δx that is (Va−Vb) / (Va + Vb) is obtained. Similarly, servo signals are also obtained from the read cells Sc and Sd. The magnetic head 1 is adjusted to the exact position (offset position C1, C2) of the magnetic band 10 to be recorded or reproduced by the tracking operation by the amplitude servo system using the servo signal Δx and the track address (S2). As a tracking control servo system, for example, a phase servo system disclosed in Japanese Patent Laid-Open No. 2000-123506 may be applied.

  Next, the rotation control unit 50 enters a state of waiting for rotation so that the magnetic band 10 to be recorded or reproduced is positioned immediately below the magnetic head 1 (S3).

  Finally, the recording / reproducing control unit 53 completes the recording operation to form the two recording tracks T in the desired magnetic band 10 by driving and controlling the magnetic head 1 at a predetermined timing. The reproduction operation of reading recorded information from the two recording tracks T in the desired magnetic band 10 is completed (S4).

  FIG. 5 shows a conventional magnetic disk X 'used as a discrete track medium. In the conventional magnetic disk X ′, one recording track T is basically formed in one magnetic band 10. Therefore, the track pitch Tp ′ is equal to the separation distance between the adjacent nonmagnetic bands 11. The head width of the magnetic head 1 is Wh ′, the width of each magnetic band 10 that is the width of the recording track T is Wnd, and the discrete width of the nonmagnetic band 11 is Wg ′.

  In such a conventional magnetic disk X ′, the relationship between the track pitch Tp ′ and the discrete width Wg ′ is as follows.

  For example, when the head width Wh ′ is 18 nm, an error due to processing accuracy of the magnetic head 1 (an increase of 20% as an example) and a detrack margin (an example of 10 nm) are taken into account, and the magnetic field extends to a 6 nm range on both sides of the magnetic head 1. Is effective, the effective magnetic field width Ws ′ that effectively acts by the magnetic head 1 is 43.6 nm.

  In order to perform recording effectively, the width Wnd of the magnetic band 10 and the discrete width Wg 'of the nonmagnetic band 11 in the magnetic disk X' must satisfy the following conditions. That is, Ws ′ <Wnd + 2Wg ′ (1).

  Here, for example, in a conventional magnetic disk X ′, which is a discrete track medium, the width of a recording track in a magnetic disk having a continuous magnetic film is about 20 nm, and the width Wnd of the magnetic band 10 is reduced by 40%. Can be Therefore, the width Wnd of the magnetic band 10 is set to Wnd = 20 / 1.4 = 14.3 nm. Substituting this into the above equation (1) results in Wg ′> 14.7 nm (2).

  The track pitch Tp ′ is Tp ′ = Wnd + Wg ′. As a result, the relationship Tp ′ = Wg ′ + 14.3 (3) is derived.

  Based on the above equations (2) and (3), the relationship between the track pitch Tp 'and the discrete width Wg' in the conventional magnetic disk X 'is a broken line graph as shown in FIG.

  On the other hand, in the magnetic disk X of the present embodiment, the relationship between the track pitch Tp and the discrete width Wg is as follows.

  For example, when the head width Wh is 18 nm, the effective magnetic field width Ws is 43.6 nm as in the conventional magnetic disk X ′. In order to perform recording effectively, the width Wnd of the magnetic band 10 and the discrete width Wg of the nonmagnetic band 11 in the magnetic disk X must satisfy the following conditions. That is, Ws <Wnn + Wm + Wg (4).

  Here, for example, the width of the recording track in a magnetic disk having a continuous magnetic film is about 20 nm, whereas in the magnetic disk X of the present invention, the width of the recording track T can be reduced by about 20%. It is considered possible. Therefore, the width Wnn of the recording track T is set to Wnn = 20 / 1.2 = 16.7 nm. The detrack margin width Wm is 10 nm. Substituting this into the above equation (4) results in Wg> 16.9 nm (5).

  The track pitch Tp is Tp = (2Wnn + Wm + Wg) / 2. This leads to the relationship Tp = Wg / 2 + 21.7 (6).

  Based on the above equations (5) and (6), the relationship between the track pitch Tp and the discrete width Wg in the magnetic disk X of the present embodiment is a solid line graph as shown in FIG. That is, when the discrete width Wg is 15 nm or more due to the manufacturing limit, the track pitch Tp of the magnetic disk X of this embodiment can be made smaller than that of the conventional magnetic disk X ′.

  Therefore, according to the magnetic disk X of the present embodiment, the recording tracks T can be accurately formed in each magnetic band 10 by two rows, so that the track pitch Tp can be made smaller than before, and consequently high recording. Densification can be further promoted.

  In addition, since the width of the magnetic band 10 can be made larger than before while the track pitch Tp is reduced, the processing accuracy of the magnetic disk X can be relaxed, and the manufacturing yield can be improved.

1 is an overall perspective view showing an embodiment of a magnetic disk device according to the present invention. FIG. 2 is an enlarged plan view of the magnetic disk shown in FIG. 1. FIG. 2 is a block diagram of the magnetic disk device shown in FIG. 1. 3 is a flowchart showing disk access processing of the magnetic disk device shown in FIG. 1. It is an enlarged plan view of a conventional magnetic disk. It is explanatory drawing for demonstrating the difference with this invention and the past.

Explanation of symbols

A magnetic disk device X magnetic disk T recording track S servo pattern area Sa to Sd reading cell 1 magnetic head 10 magnetic band 11 non-magnetic band

Claims (3)

A magnetic head, a plurality of magnetic bands on which recording tracks for recording information by the magnetic head are formed, a nonmagnetic band that delimits these magnetic bands, and adjacent to the ends of the magnetic band and the nonmagnetic band A magnetic disk device comprising a magnetic disk having a servo pattern area for tracking,
An offset position that identifies the center position in the width direction of each magnetic band by reading the servo pattern area with the magnetic head, and identifies a plurality of offset positions that deviate from the center position in the width direction by a predetermined amount in the disk radial direction. Specific means,
Recording control means for forming at least two rows of the recording tracks on the inner side and the outer side in the disk radial direction on each magnetic band by performing recording control in a state where the magnetic head is aligned with each offset position;
A magnetic disk device comprising: 2. The magnetic disk device according to claim 1 , wherein the recording control unit forms a recording track while taking a margin of a predetermined width between the plurality of recording tracks in each magnetic band region. A magnetic disk having a plurality of magnetic bands on which recording tracks are formed by a magnetic head, a nonmagnetic band separating these magnetic bands, and a servo pattern area for tracking adjacent to the ends of these magnetic bands and nonmagnetic bands On the other hand, a magnetic disk recording control method for forming the recording track by recording control,
An offset position that identifies the center position in the width direction of each magnetic band by reading the servo pattern area with the magnetic head, and identifies a plurality of offset positions that deviate from the center position in the width direction by a predetermined amount in the disk radial direction. Specific steps,
A recording control step of forming at least two rows of the recording tracks in each magnetic band by performing recording control in a state where the magnetic head is aligned with each offset position;
Are sequentially executed, and a magnetic disk recording control method.

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