JPH1153851A - Magnetic disc and magnetic disc device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disc and a magnetic disc device which can generate a satisfactory head-position-error signal, realize a high precision head positioning and improve a memory density and a memory capacity. SOLUTION: A track code which is provided in the servo information region 2b of a magnetic disc is composed of a Gray code whose pitch is 1/N (wherein N denotes an integer not smaller than 2) of a track pitch. Further, the widths of four burst patterns A, B, C and D in the direction of the disc radius are 1/N of the track pitch. The burst patterns A and B are arranged on both the sides of track center lines and the burst patterns C and D are arranged on both the sides in the radial direction of dividing lines by which a distance between the adjacent two track center lines is divided into N divisions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk for recording and reproducing information using magnetism and a magnetic disk drive, and more particularly to a head positioning technique.

[0002]

2. Description of the Related Art In recent years, technology development for increasing the speed and increasing the track density of a magnetic disk drive has been actively pursued. In particular, in a high track density technology, a magnetoresistive effect type (hereinafter, MR)
With the advent of heads, the track density has been dramatically improved compared to conventional inductive heads. MR heads generally have higher head reproduction sensitivity than conventional inductive heads, and can reduce the track width. Therefore, an MR inductive composite head using an inductive head as a recording head and an MR head as a reproducing head is widely used in magnetic disk devices. The magnetic disk drive using the MR inductive composite type head employs a wide write / narrow read system that performs reproduction with a track width narrower than the recording track width, utilizing the high reproduction sensitivity of the MR head, and has an off-track characteristic. Is also excellent. Also, in order to realize a high track density, a head positioning technique becomes very important. In a general head positioning method, positioning information recorded in a servo information area of a magnetic disk in advance is reproduced to perform a head positioning operation. Various proposals have been made for a magnetic disk on which the positioning information is recorded and a magnetic disk device for generating a head position error signal from the positioning information. For example, there are those disclosed in JP-A-6-68623 and JP-A-7-45020.

[0003] Such a conventional magnetic disk and magnetic disk device will be described with reference to the drawings.

FIG. 8 is a plan view showing a servo information area 102 recorded on a conventional magnetic disk, and FIG. 9 is a servo pattern diagram thereof. In FIG. 8, the magnetic disk 10
1 has a plurality of concentric tracks, and a plurality of servo information areas 102 and data information areas 103 are alternately arranged on each track. The servo information area 102 is arranged at the same angle on the radiation from the center of rotation of the magnetic disk 101. In FIG. 9, the servo information area 10
Reference numeral 2 denotes an AGC unit 104 in which a pattern for determining the amplification factor of a reproduction signal in the servo information area 102 is recorded; an erase unit 105 in which nothing is recorded for identifying the servo information area; It is composed of a track code section 106 which is coded and recorded, and a position error information section 107 for detecting how much the head deviates from the track center.

[0005] The track code section 106 is a gray code (Gr) that differs by 1 bit between adjacent tracks.
ay code). At the time of head seek, this track code is converted into a track address, and the head can be positioned with a precision of ± 1 track relative to a desired track position. The position error information section 107 includes four burst patterns of A burst, B burst, C burst, and D burst, and the width of the burst pattern in the radial direction is substantially the same as the track pitch. The A burst and the B burst are respectively arranged on both sides in the radial direction with respect to the track center line. The C burst and the D burst are disposed on both sides in the radial direction with respect to the center between two adjacent track center lines. The head positioning operation is performed based on the change in the amplitude value of the detection output of the four burst patterns.

FIG. 10 is a block diagram showing a method for generating a position error signal of a magnetic disk drive using the conventional magnetic disk 101 shown in FIGS. 8 and 9. In FIG. 10, the reproduction track width of the magnetic head 115 has a width substantially equal to the track pitch of the magnetic disk 101. The track code detection unit 108 detects a track code recorded in a gray code pattern based on a reproduction signal of the track code unit 106 in the servo information area 102 of the magnetic disk 101. The track address generation unit 109 generates a track address from the detected track code. The burst amplitude detection unit 110
The amplitude of the detection output of each burst pattern of the position error information section 107 of the servo information area 102 is measured.

[0007] The first arithmetic unit 111 subtracts the amplitude value of the B burst from the amplitude value of the A burst. Second arithmetic unit 1
12 subtracts the amplitude value of the A burst from the amplitude value of the B burst. The comparing unit 113 compares the amplitude values of the C burst and the D burst, and outputs a result of the comparison. The position error signal generation unit 114 switches the outputs of the first calculation unit 111 and the second calculation unit 112 based on the result of the comparison unit 113 and outputs the output as a position error signal.

FIG. 11 is a diagram showing a position error signal of a conventional magnetic disk drive. In the figure, A1-B obtained by subtracting the amplitude value B1 of the B burst from the amplitude value A1 of the A burst when the head moves in the track direction indicated by the arrow X.
1 shows a burst operation signal of 1 and a C1-D1 burst operation signal obtained by subtracting the amplitude value D1 of the D burst from the amplitude value C1 of the C burst. Further, when the amplitude C1 is larger than the amplitude D1, a burst operation signal of A1-B1 is shown, and when the amplitude C1 is smaller than the amplitude D1, a position error signal consisting of a B1-A1 burst operation signal is shown.

Next, the operation of generating a position error signal of the magnetic disk drive configured as described above will be briefly described. 8 to 10, the position error information section 107 of the servo information area 102 of the magnetic disk 101 is reproduced by a head having a head width substantially equal to the track pitch, and the amplitude value of each burst pattern is detected by the burst amplitude detection section 110. I do. The amplitude values of the detected and output A burst and B burst are output to the first calculation unit 111 and the second calculation unit 112, respectively. Further, the amplitude values of the C burst and the D burst are output to the comparing unit 112. Next, the first calculation unit 111 outputs a value obtained by subtracting the amplitude value of the B burst from the amplitude value of the A burst to the position error signal generation unit 114. Further, the second calculation unit 112 outputs a value obtained by subtracting the amplitude value of the A burst from the amplitude value of the B burst to the position error signal generation unit 114. The comparing section 113 compares the amplitude value of the C burst with the amplitude value of the D burst, and generates a position error signal generating section 1 using a binarized signal indicating a magnitude relationship between the compared amplitude values.
14 is output. When the amplitude value of the C burst is larger than the amplitude value of the D burst, the position error signal
The output of the first arithmetic unit 111 is generated as a position error signal, and when the amplitude value of the C burst is smaller than the amplitude value of the D burst, the output of the second arithmetic unit 112 is generated as a position error signal. The magnetic disk drive performs a positioning operation with the head at the track center using the position error signal.

[0010]

In a conventional magnetic disk and magnetic disk apparatus as described above, a head whose reproducing head width is sufficiently smaller than a recording head width, such as an MR inductive combined type head, that is, a track pitch is smaller. Therefore, when a head having a sufficiently small reproducing head width is used, a good position error signal cannot be generated. The reason is,
It is as follows. Since the width of the burst pattern is wider than the width of the reproducing head, the detection output of the reproducing head does not change in a range where the positional deviation between the reproducing head and the recording track is smaller than the difference between the widths of the two. Therefore, no displacement can be detected. For this reason, when the reproducing head having the above relationship is used, highly accurate head positioning with respect to the track center cannot be performed. Therefore, the conventional example using the head having the above relationship has a problem that the head access time becomes long and the recording density and the storage capacity cannot be sufficiently increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to generate a good head position error signal even when the reproducing head width is sufficiently smaller than the track pitch, to realize highly accurate head positioning, and to perform recording. An object of the present invention is to provide a magnetic disk and a magnetic disk device capable of improving the density and the storage capacity.

[0012]

In order to solve the above-mentioned problems, a magnetic disk of the present invention uses a 1 / N (N is an integer of 2 or more) track pitches for track address determination. A track code part for giving identification information;
At least two position error information sections for recording position error information between the track center line and the head, which are recorded on both sides in the radial direction with respect to the track center line and at different positions in the rotation direction, are provided.

As described above, the magnetic disk of the present invention
Since the track code for every / N track pitch can be detected, it is possible to perform positioning with accuracy of ± 1 / N track pitch at the time of head seek, and it is possible to shorten the head positioning time.

According to the magnetic disk drive of the present invention, 1 / N (N
Is an integer of 2 or more) A division line obtained by dividing a distance between a track center line and two adjacent track center lines into N by dividing the distance between a track code section that provides identification information for track address determination recorded at each track pitch. A magnetic disk having a position error information portion having a plurality of burst patterns having substantially the same width as the track pitch, recorded on both sides in the radial direction and at different positions in the rotational direction with respect to the read head width. A magnetic head that is approximately 1 / N with respect to a track pitch, track code detection means for reproducing a track code portion recorded on the magnetic disk using the magnetic head, and generating a track code signal; A track address generating means for generating a data track address from a signal; and recording on the magnetic disk using the head. Burst amplitude detecting means for detecting the reproduced signal amplitudes of the plurality of burst patterns in the position error information section, and a difference between two amplitude values among the amplitude values of each burst pattern detected by the burst amplitude detecting means. Position error signal generating means for outputting as an error signal, and selection of amplitude values of two burst patterns necessary for the position error generating means to obtain a position error signal in accordance with a change in amplitude values of the plurality of burst patterns. And a controller for instructing

As described above, according to the magnetic disk drive of the present invention, even when a magnetic head whose reproducing head width is approximately 1 / N with respect to the track pitch is used, the magnetic head apparatus can respond to changes in the amplitude values of a plurality of burst patterns. Since the calculation of the amplitude value of the burst pattern can be performed freely, a good position error signal can be generated.
A highly accurate head positioning is realized, and the recording density and the storage capacity can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of the magnetic disk of the present invention will be described below with reference to FIGS.

Embodiment 1 FIG. 1 is a plan view showing a servo information area recorded on a magnetic disk according to Embodiment 1 of the present invention. . In FIG. 1, the magnetic disk 1a has a plurality of concentric tracks, and a plurality of servo information areas 2a and data information areas 3 are alternately arranged on each track. Also, each servo information area 2a has a magnetic disk 1a.
Are arranged at the same angle on the radiation from the center of rotation.

FIG. 2 is a servo pattern diagram of the servo information area 2a. In the figure, in the servo information area 2a, an AGC section 4 which is a pattern for determining the amplification factor of the reproduction signal in the servo information area 2a, and an erase section 5 in which nothing is recorded for identifying the servo information area. And a track code portion 6 in which a track address is encoded and recorded.
And a position error information section 7a for detecting how much the head deviates from the track center. The track code section 6 is composed of a gray code track code recorded at every 1/2 track pitch. The track code is a pattern which is converted into a track address at the time of head seek and enables head positioning with a precision of ± 1/2 track with respect to a desired track address position. This enables high-precision head positioning even when the reproducing head width is half the track pitch.

The position error information section 7a is composed of four burst patterns of A burst, B burst, C burst, and D burst, and the radial width of the burst pattern is substantially the same as the track pitch. A burst,
The B bursts are arranged on both sides in the radial direction with respect to the track center line. The C burst and the D burst are arranged on both sides in the radial direction with respect to a dividing line obtained by dividing a distance between two adjacent track center lines into two. The head positioning operation is performed based on the change in the detected amplitude value of the four burst patterns.

In the above description, the gray code is recorded in the track code section 6 at every 1/2 track pitch. However, the gray code and 6 burst patterns are recorded at every 1/3 track pitch. The configuration may be as follows.
In this case, at the time of head seek, positioning can be performed with ± 1/3 track accuracy with respect to a desired track address position.
As described above, good head positioning can be realized.
The positioning operation will be described later in detail.

Embodiment 2 FIG. 3 shows a servo information area 2b recorded on a magnetic disk according to Embodiment 2 of the present invention.
FIG. 4 is a servo pattern diagram of the servo information area 2b.
In FIG. 4, only the configuration different from the first embodiment will be described. The position error information section 7b is composed of four burst patterns of A burst, B burst, C burst, and D burst, and the width in the radial direction of each burst pattern is approximately の of the track pitch. The A burst and the B burst are arranged on both sides in the radial direction with respect to the track center line. The C burst and the D burst are arranged on both sides in the radial direction with respect to a division line L1 obtained by dividing the distance between two adjacent track center lines into four. The head positioning operation is performed based on the change in the amplitude values of the four burst patterns. By setting the width of the burst pattern in the radial direction to ト ラ ッ ク of the track pitch, high-precision head positioning can be performed even when the reproducing head width is の of the track pitch. The positioning operation will be described later in detail.

Third Embodiment FIG. 5 is a block diagram of a position error signal generating device for a magnetic disk drive according to a third embodiment of the present invention. In this embodiment, the magnetic disk 1a of the first embodiment is used. In FIG. 5, the reproduced output from the magnetic head 13 is sent to the track code detector 8, the A burst amplitude detector, the B burst amplitude detector, the C burst amplitude detector, and the D burst amplitude detector of the burst amplitude detector 10. Is entered. Each output terminal of the A burst amplitude detection unit, the B burst amplitude detection unit, the C burst amplitude detection unit, and the D burst amplitude detection unit is connected to each input terminal of the controller 12,
It is connected to each input terminal of the selection circuit 11a of the position error signal generator 11. Two output terminals of the selection circuit 11a are connected to respective input terminals of the operation circuit 11b. The output terminal of the controller 12 is connected to another input terminal of the selection circuit 11a and another input terminal of the operation circuit 11b. The output end of the track code detector 8 is connected to the track address generator 9. The magnetic head 13 has a reproduction track width of approximately 1 track pitch of the magnetic disk 1a.
/ 2. The track code detection section 8 detects a track code recorded in a gray code pattern based on a reproduction signal of the track code section 6 in the servo information area 2a of the magnetic disk 1a. The track address generator 9 generates a track address from the detected track code. The burst amplitude detector 10 measures the amplitude value of the detection signal of each burst pattern of A burst, B burst, C burst, and D burst of the position error information section 7a in the servo information area of the magnetic disk 1. Position error signal generator 11
Is 2 among the amplitude values of the detection signal of each burst pattern.
Selection circuit 11 for selecting the amplitude value of one burst pattern
a and an arithmetic circuit 11b that calculates the amplitude values of the two burst patterns selected by the selection circuit 11a. The controller 12 indicates the amplitude values of the two burst patterns selected by the selection circuit 11a according to the change in the amplitude value of each burst pattern.

FIG. 6 is a diagram showing a position error signal of the magnetic disk drive according to the third embodiment of the present invention. FIG. 6 shows a burst operation signal A1-B1 obtained by subtracting the amplitude value B1 of the B burst from the amplitude value A1 of the A burst when the magnetic head moves in the track direction indicated by the arrow X, and the amplitude value C1 of the C burst. C1-D obtained by subtracting the amplitude value D1 of the D burst from
1 shows a burst operation signal.

<< Description of Positioning Operation Common to Each of the Above Embodiments >> Next, the operation of generating a position error signal of the magnetic disk device configured as described above will be described with reference to FIG. The position error information section 7a of the servo information area 2a of the magnetic disk 1a is reproduced by the magnetic head 13 having a head width of about 1/2 of the track pitch, and the amplitude value of each burst pattern is detected by the burst amplitude detection section 10. A detected
The amplitude value of each detection signal of the burst, the B burst, the C burst, and the D burst is output to the selection circuit 11a of the position error signal generator 11 and the controller 12. The amplitude values of A burst, B burst, C burst, and D burst are A1, B1, C1, and D1, respectively. Controller 1
2 is a position error signal generator 1 that generates a difference A1-B1 of the amplitude values as a position error signal when the amplitude value D1 is 0.
Command 1 Similarly, when the amplitude value A1 is 0, the difference C1
When the amplitude value C1 is 0, the position error signal generation unit 11 is instructed to generate the difference B1-A1 when the amplitude value C1 is 0 and the difference D1-C1 when the amplitude value B1 is 0 as the position error signal. . By controlling the head 13 using the position error signal generated by the position error signal generator 11, good head positioning can be achieved.

In the above description, the magnetic head 13 has a reproducing head width that is approximately 1/2 of the track pitch of the magnetic disk 1a. 2 adjacent to the track center line
This is an example of generating a position error signal by selecting two out of four burst patterns at both sides in the radial direction with respect to a dividing line that divides the track pitch of two tracks into two and at positions different from each other in the rotational direction. explained. As another example, the reproduction track width of the magnetic head 13 is approximately 1/3 of the track pitch.
In this case, six burst patterns are provided on both sides in the radial direction with respect to the dividing line that divides the track pitch into three, and at different positions in the rotational direction. If two position patterns are selected from the six burst patterns to generate a position error signal, a position error signal similar to the above can be generated, and good head positioning can be realized.

The magnetic head in the above description may be a composite magnetic head in which an inductive head used for recording and an MR head used for reproduction are integrated. FIG. 7 is a partial perspective view of the MR inductive composite head. As shown in the figure, the reproduction width Sw is sufficiently smaller than the recording width Kw.

[0027]

According to the magnetic disk of the present invention, a track code section for giving identification information for track address determination recorded at every 1 / N (N is an integer of 2 or more) track pitches, and at least a track center line By providing a position error information section for recording position error information between the track center line and the head, which is recorded on both sides in the radial direction and at different positions with respect to the rotation direction, the track at every 1 / N track pitch is provided. Code can be detected. Therefore, it is possible to perform positioning with a positioning accuracy of ± 1 / N track pitch at the time of head seek, and it is possible to shorten the head positioning time, thereby realizing high-speed access.

According to the magnetic disk drive of the present invention, 1 / N (N
Is an integer of 2 or more) A division line obtained by dividing a distance between a track center line and two adjacent track center lines into N by dividing the distance between a track code section that provides identification information for track address determination recorded at each track pitch. And a position error information portion having a plurality of burst patterns having substantially the same width as the track pitch at both sides in the radial direction with respect to the rotation direction. Further, the reproducing head width is approximately 1 / N with respect to the track pitch (N is 2
A track code detecting section that reproduces a track code section recorded on the magnetic disk using the magnetic head and generates a track code signal; and A track address generation unit for generating a data track address, a burst amplitude detection unit for detecting a reproduction signal amplitude of a plurality of burst patterns of a position error information unit recorded on the magnetic disk using the head, and a burst amplitude detection unit Means for outputting a difference between two amplitude values from among the amplitude values of each burst pattern detected by the means as a position error signal; and Instructs the error generation unit to select the amplitude values of the two burst patterns necessary for obtaining the position error signal. It is equipped with a controller for. With the above configuration, even when a magnetic head having a read head width of 1 / N of the track pitch is used, the calculation of the amplitude value of the burst pattern is performed in accordance with the change in the amplitude value of the plurality of burst patterns. A position error signal can be generated, and using this, a highly accurate head positioning can be realized, and the recording density and the storage capacity can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a magnetic disk according to a first embodiment of the present invention.

FIG. 2 is a servo pattern diagram of a servo information area of the magnetic disk according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a configuration of a magnetic disk according to a second embodiment of the present invention.

FIG. 4 is a servo pattern diagram of a servo information area of a magnetic disk according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a position error signal generation device for a magnetic disk drive according to Embodiment 3 of the present invention.

FIG. 6 is a diagram showing a position error signal of a magnetic disk drive according to Embodiment 3 of the present invention.

FIG. 7 is a perspective view showing a configuration of an MR inductive composite head.

FIG. 8 is a plan view showing a configuration of a conventional magnetic disk.

FIG. 9 is a servo pattern diagram of a servo information area of a conventional magnetic disk.

FIG. 10 is a block diagram showing a conventional position error signal generating device for a magnetic disk drive.

FIG. 11 is a diagram showing a position error signal of a conventional magnetic disk drive.

[Explanation of symbols]

 1a, 1b Magnetic disk 2a, 2b Servo information area 3 Data information area 4 AGC section 5 Erase section 6 Track code section 7a, 7b Position error information section 8 Track code detection section 9 Track address generation section 10 Burst amplitude detection section 11 Position error Signal generation unit 11a Selection circuit 11b Arithmetic circuit 12 Controller 13 Magnetic head 101 Magnetic disk 102 Servo information area 103 Data information area 104 AGC unit 105 Erase unit 106 Track code unit 107 Position error information unit 108 Track code detection unit 109 Track address generation unit Reference Signs List 110 Burst amplitude detection unit 111 First calculation unit 112 Second calculation unit 113 Comparison unit 114 Position error signal generation unit 115 Magnetic head

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Nagaishi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] An identification information for determining a track address, which is recorded at every 1 / N (N is an integer of 2 or more) track pitches on a magnetic disk having a plurality of concentric tracks on which servo information is recorded. A track code portion to be provided; and at least two position error information portions that record position error information of the head with respect to the track center line, which are recorded on both sides in the radial direction with respect to the track center line and at different positions in the rotation direction. A magnetic disk comprising: 2. The position error information section includes: a distance between a track center line and a division line obtained by dividing a distance between two adjacent track center lines into N; 2. The magnetic disk according to claim 1, comprising a plurality of burst patterns recorded at different positions and having substantially the same width as the track pitch. 3. The position error information section includes: a distance between a track center line and a division line obtained by dividing a distance between two adjacent track center lines into N; 2. The magnetic disk according to claim 1, wherein a plurality of burst patterns having a width of about 1 / N of a track pitch are provided at different positions. 4. A magnetic disk having a plurality of concentric tracks on which servo information is recorded is provided with identification information for determining a track address recorded at every 1 / N (N is an integer of 2 or more) track pitches. A track code part, a track center line, and a dividing line obtained by dividing the distance between two adjacent track center lines into N parts, on both sides in the radial direction,
A magnetic disk provided with a position error information portion having a plurality of burst patterns having substantially the same width as the track pitch recorded at different positions in the rotation direction; N a magnetic head; a track code detecting means for reproducing a track code portion recorded on the magnetic disk using the magnetic head to generate a track code signal; and generating a data track address from the track code signal. Track address generating means; burst amplitude detecting means for detecting the reproduction signal amplitudes of a plurality of burst patterns of a position error information portion recorded on the magnetic disk using the head; and a plurality of burst signals detected by the burst amplitude detecting means. The difference between two amplitude values from among the amplitude values of the burst pattern of A position error signal generating means for outputting, in response to the change in the amplitude value of each burst pattern, necessary for obtaining a position error signal to the position error generation means 2
A controller for instructing selection of the amplitude value of one burst pattern. 5. The magnetic disk drive according to claim 4, wherein the magnetic head is a composite magnetic head in which an inductive head used for recording and a magnetoresistive head used for reproduction are integrated.