JP2003016745A - Disk storage and method for positioning head in the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a harmful effect on an adjacent track due to writing by realizing a track pitch that is sufficiently larger than a track width where data are written while using a disk on which burst patterns for realizing a prescribed track pitch are recorded. SOLUTION: A second track pitch area for substituting for a track on a first track pitch area is provided on the recording surface of a disk, and when it is predicted that there is the possibility that a harmful effect is produced on an adjacent track by writing data to a target track on the first track pitch area, an optional track on the second track pitch area is assigned as an alternate destination of the target track. On the second track pitch area, for example, a pair of burst signals C and D is skipped extra by one to position a head in comparison with a case where the first track pitch is realized so as to be able to realize the second track pitch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk storage device for positioning a head on a target track based on servo data previously recorded on a disk, and a head positioning method in the device.

[0002]

2. Description of the Related Art A magnetic disk device (HDD) is a typical disk storage device that uses a disk as a recording medium and uses a large number of concentric tracks formed on the disk as data recording areas.

Generally, in a magnetic disk device, a plurality of servo areas in which servo data are recorded are arranged on a disk (magnetic disk) radially from the center of the disk at regular intervals in the disk circumferential direction, and reproduction is performed from this servo area. The head seeks and positions on the target track based on the servo data. Servo data is roughly divided into a track code and servo burst data. The track code is an address for identifying each track (cylinder) and is used for seek control for moving the head to the target track. On the other hand, the servo burst data indicates the position error in the track (cylinder) indicated by the corresponding track code by the amplitude of the waveform and is called a servo burst pattern. This servo burst pattern is generally composed of a pair of first phase burst signals A and B and a pair of second phase burst signals C and D.

In the prior art, the relationship between the servo burst pattern and head positioning is as shown in FIG. 2 (b). First, the length of the burst signals A, B, C, and D as position error signals used for head positioning in the disk radial direction is 2 / n (n is an integer) of the track pitch TP1, for example, 2/3. . Track pitch TP1,
That is, the width between the centers of adjacent tracks is set to be slightly wider (for example, about 20% wider) than the width of the head (physical length of the head in the disk radial direction). Here, the head width is also called a track width.

The burst signals A, B, C and D are respectively shifted in the disk radial direction (vertical direction in the figure) by an interval of ⅓ of the track pitch TP1 and predetermined in the disk circumferential direction (horizontal direction in the figure). Is recorded with a length L of. That is, the burst signals A, B, C and D are recorded (arranged) in a zigzag pattern.

The burst signal A recorded as described above,
By the positioning control (servo control) using the servo burst pattern consisting of B, C, and D, the head is moved to, for example, FIG.
When the head is positioned at the head position # 1 in (b), the head is controlled with the boundary between the burst signals A and B along the disk circumferential direction as the track center. Next, the head is shown in FIG.
When the head is positioned at the head position # 2 in (b), the head is controlled with the track center at the boundary between the burst signals C and D along the disk circumferential direction in the radial direction. Positioning of the head after head position # 3 is repeated in the same manner.

When the head is positioned by such a method, since the track pitch is set to be slightly wider than the track width, there is a slight gap between the tracks on which signals are actually recorded and reproduced. However, there is a gap. This gap is called a guard band.

In general, the head flies over the disk with a predetermined flying distance. The magnetic flux generated from the recording element (recording head) of the head has a property of spreading when it appears in space. Therefore, at the position where the magnetic flux reaches the disk, the magnetic flux is wider than the width of the head recording element (head width). In addition to this, the width of the track actually recorded on the disk becomes wider than the head width due to the phenomenon of "bleeding" (when the temperature is high) in which the magnetized portion extends outside the magnetic flux on the disk. Therefore, in the conventional technique, the pitch with the adjacent track, that is, the track pitch is slightly smaller than the head width (track width) (for example, 20).
%), The gap between the recorded track and the adjacent track is kept constant while minimizing the decrease in the recording density (track density) of the disc.
In other words, it is designed so that a guard band can be secured. The presence of this guard band prevents the recorded track from adversely affecting the data on the adjacent track due to the spread of the magnetic flux from the recording head during data recording.

[0009]

As described above, in the prior art, by setting the track pitch to be slightly wider than the width of the recording head, it is possible to minimize the decrease in track density and to record recorded tracks. A guard band is secured between the adjacent track and the adjacent track to prevent the adjacent tracks from interfering with each other due to the spread of the magnetic flux from the recording head during data recording.

However, with the width of the guard band secured by the above-mentioned conventional technique, it is necessary to increase the current (write current) applied to the recording head or the write track position due to head positioning error caused by some disturbance. In the case where the tracks are displaced, there is a possibility that interference between adjacent tracks cannot be prevented for the following reason.

First, the spread of the magnetic flux emitted from the recording head (recording element) to the space depends on the magnitude of the current (write current) applied to the recording head, and the larger the write current, the larger the spread.

On the other hand, when the environmental temperature of the device is lowered, the magnetic characteristics of the disk are changed and the magnetic field is changed so that a large change in magnetic field is required. Therefore, at a low temperature, in order to increase the write capability (magnetic flux density) of the head, a write current larger than that at room temperature is required.

As described above, under an environment requiring a large write current, such as at a low temperature, the spread of the magnetic flux from the recording head becomes large due to the influence of the large write current. Therefore, with the width of the guard band secured by the above-mentioned conventional technique, the decrease in track density can be suppressed to the minimum, but the interference between adjacent tracks cannot be prevented in the situation where the write current has to be increased. There is a risk.

Further, at high temperatures, the spread of the magnetic flux does not become large because the write current is small, but the "bleeding" of the magnetized portion becomes large, so that the width of the guard band secured by the above-mentioned prior art is: There is also a possibility that the data of the adjacent track may be adversely affected.

Further, even if the head positioning error becomes large due to some disturbance and the write track position is displaced, the width of the guard band secured by the above-mentioned conventional technique may adversely affect the data of the adjacent track. There is.

As described above, in the prior art, since the track pitch is set slightly wider than the width of the recording head, the decrease in track density can be suppressed to the minimum, but the track width is smaller than the track width when writing data. When the magnetic flux spreads over a wide range or the write track position is deviated due to the positioning error of the head, there is a problem that the data on the adjacent track is adversely affected.

The present invention has been made in consideration of the above circumstances, and an object thereof is to use a disk on which a servo burst pattern for realizing a predetermined track pitch is recorded and to use a disk wider than the predetermined track pitch. The present invention provides a disk storage device and a head positioning method for the same, which can change and set a track pitch sufficiently wider than a track width for writing data, thereby reducing adverse effects between data writing and an adjacent track. Especially.

[0018]

DISCLOSURE OF THE INVENTION A disk storage device according to a first aspect of the present invention is a servo burst pattern used for positioning a head on a target track on each recording surface of a disk, which are mutually complementary. A disk storage in which a row of the same servo burst pattern composed of a plurality of different burst signal pairs is recorded radially in the disk radial direction and at equal intervals in the disk circumferential direction, and a first track pitch can be realized. A device, which is a ring-shaped specific area set to have a second track pitch larger than the first track pitch on at least one recording surface of at least one disk, A specific area used to replace the track on the area is configured in advance, and data is written to the target track on the disc. Means for predicting occurrence of interference with adjacent tracks due to congestion, means for allocating an arbitrary track on the specific area as an alternative destination of the target track according to the prediction result of the predicting means, and the specific area When the head is positioned on the above alternative destination track, a head positioning means for selecting a burst signal pair used for positioning so that the track pitch of the specific area becomes the second track pitch is provided. To do. Here, as the servo burst pattern, the first-phase burst signal A, which is well known in the art,
A servo burst pattern or the like composed of a pair of B and burst signals C and D of the second phase, which are deviated by a certain length in the disk radial direction with respect to the pair of burst signals A and B of the first phase, is applied It is possible.

In such a structure, although the row of the servo burst pattern used to realize the first track pitch is the area on the disk where the row is recorded,
In the specific area, a track pitch wider than the first track pitch (second track pitch) can be realized by selecting a burst signal pair used for positioning so that the track pitch becomes the second track pitch. Become.
That is, it becomes possible to widen the guard band. Therefore, when it is predicted that the data writing to the target track on the disk will cause interference with the adjacent tracks, for example, when the environmental temperature of the device is lower than the low temperature side reference temperature (that is, the write current supplied to the head When the correction is required to increase), or when the temperature is higher than the high temperature side reference temperature, or when the disturbance applied to the device exceeds the reference value (that is, when the positioning error increases and the positioning accuracy falls below the reference accuracy). It is possible to reduce the interference with the adjacent track due to the data writing even in the situation where the interference with the adjacent track may be caused in the related art, such as).

Here, it is preferable to provide temperature detecting means such as a temperature sensor for detecting the environmental temperature and disturbance detecting means such as an acceleration sensor for detecting a disturbance, that is, a vibration, a shock, etc. applied to the apparatus. These detecting means may be provided on either side of the disk storage device or the host system that uses the disk storage device.

Further, on at least one recording surface of at least one disk, a plurality of ring-shaped identifications are set so as to have second track pitches larger than the first track pitch and different from each other. It is also possible to secure a region and select and use one of the plurality of specific regions according to the expected degree of interference with an adjacent track.

It is also possible to use all the recording surfaces of all the disks at the second track pitch. In this case, although the disk storage device is premised to be used at the first track pitch, a track pitch wider than the pitch can be realized, and it is possible to reduce interference with adjacent tracks due to data writing. Becomes

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment in which the present invention is applied to a magnetic disk device will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a magnetic disk device according to an embodiment of the present invention. In the magnetic disk device (hereinafter referred to as HDD) of FIG. 1, 11 is a disk (magnetic disk medium) as a recording medium on which data is magnetically recorded, 12 is data writing to the disk 11 (data recording) and from the disk 11. Head (magnetic head) used for reading data (reproducing data)
Is. The head 12 is a reproducing head 1 including an MR element.
21 and a recording head 12 including an inductive type recording thin film element
2 is a recording / reproducing separated type head (composite head) integrated on the same slider. The head 12 is the disk 1
It is assumed that they are provided corresponding to the respective recording surfaces of 1. In the configuration of FIG. 1, an HDD including a single disk 11 is assumed, but an HDD in which a plurality of disks 11 are stacked may be used.

On each recording surface of the disk 11, a plurality of servo areas 110 are arranged radially from the disk center and at equal intervals in the disk circumferential direction. Servo area 110
Servo data used for seek / positioning of the head 12 is recorded in the. This servo data is roughly composed of a track code and servo burst data (servo burst pattern), as described in the section of the prior art.

Each recording surface of the disk 11 is concentrically divided into a first track pitch area 111, a second track pitch area 112, and a system area 113 for management. The first track pitch area 111 is, for example, an area on the outer peripheral side of the disk 11, and has a reference track pitch TP.
Set to 1. The second track pitch region 112 is a region on the inner circumference side of the disk 11, and is set to a track pitch (second track pitch) TP2 larger than the reference track pitch (first track pitch). That is, the second track pitch region 112 has a lower track density than the first track pitch region 111. The system area 113 is the innermost side area of the disk 11, that is, the second area.
Is an area on the inner peripheral side of the track pitch area 112.
Track pitch (track density) of system area 113
Matches the track pitch (track density) of the second track pitch region 112.

The first track pitch area 111 is an area which the user can freely use. On the other hand, the second track pitch area 112 and the system area 113 are areas that cannot be freely used by the user. The second track pitch area 112 is a track on the first track pitch area 111 designated by the instruction when the state of the HDD when executing the write instruction from the host system is in a specific state described later. It is used as the area of the alternative track.

The system area 113 is used to store system management information. The system management information includes track substitution management information (tracks) indicating the correspondence between the tracks on the first track pitch area 111 replaced by the tracks on the second track pitch area 112 and the tracks of the replacement destination. Alternative management table).

The disk 11 is a spindle motor (hereinafter,
It rotates at a high speed by (SPM) 13). Head 1
2 is attached to an actuator (rotary type head actuator) 14 as a head moving mechanism,
The disk 11 is moved in the radial direction according to the rotation (angle rotation) of the actuator 14. As a result, the head 12 seeks and is positioned on the target track. The actuator 14 is a voice coil motor (hereinafter, C
15) and is driven by the VCM 15.

The SPM 13 and VCM 15 are driver I
It is driven by the drive currents (SPM current and VCM current) respectively supplied from C16.

The head 12 is connected to a head IC (head amplifier circuit) 17. Head IC17 is head 1
2 has a read amplifier for amplifying the read signal read by 2 and a write amplifier for converting write data into a write current.

The head IC 17 is a read / write IC
(Read / write channel) 18 is connected. The read / write IC 18 is an A / D for the read signal.
Various signal processing such as (analog / digital) conversion processing, write data encoding processing, and read data decoding processing are executed. The read / write IC 18 has a pulsing function of pulsing a read signal and outputting it as pulsed read data, and a burst signal (here, a burst signal in the servo data) according to a timing signal (burst timing signal) from the gate array 19. A, B, C,
It has a function of extracting D). This burst signal is sent to the CPU 25 and used for positioning control for positioning the head 12 on a target track, that is, track following control.

The gate array 19 is a read / write IC.
It has a function of generating various timing signals including a burst timing signal from a read pulse output from 18, and a function of extracting a track code included in servo data. This track code is the CPU21
And is used for seek control for moving the head 12 to the target track.

A disk controller (hereinafter referred to as HDC) 20 is connected to a host system that uses an HDD. The host system is a digital device such as a personal computer. The HDC 20 processes the read data encoded by the read / write IC 21 in accordance with each control signal from the gate array 19 to generate data to be transferred to the host system. Further, the HDC 20 encodes the write data transferred from the host system in accordance with each control signal from the gate array 19 and transfers it to the read / write IC 18.

The CPU 21 includes a ROM (Read Only Memory) 22 in which a control program including a control routine for head positioning executed by the CPU 21 is stored,
A RAM (Rand that provides a work area for the CPU 21)
om Access Memory) 23. CPU21
A temperature sensor 24 for detecting the temperature of the environment in which the HDD is placed and an acceleration sensor 25 used as a shock sensor for detecting a disturbance such as vibration or shock are not shown in the figure.
/ D (analog / digital) converter. The ROM 22 has two areas 111, 11 having different track pitches (track densities) on the disk 11.
Information indicating the relationship between 2 and the track pitch is stored in advance.

The CPU 21 controls the entire apparatus (HDD) according to the control program stored in the ROM 22,
For example, seek / positioning control of the head 12 based on the track code extracted by the gate array 19 and the burst signal extracted by the read / write IC 18, HD according to the read / write command from the host system
Read / write control by C20 is executed.

In the seek / positioning control of the head 12 in accordance with the write command from the host system, the CPU 21 also responds to the temperature detected by the temperature sensor 24 or the acceleration detected by the acceleration sensor 25, that is, the vibration / shock. Whether to replace the track on the first track pitch area 111 designated by the instruction with the track on the second track pitch area 112, that is, the first track pitch area
Of the track pitch area 111 or the second track pitch area 112 of which data is to be written.

A buffer RAM 26 is connected to the HDC 20. The buffer RAM 26 is a buffer used for temporarily storing data (write data) transferred from the host system to be written to the disk 11 and data (read data) read from the disk 11 and transferred to the host system. The area 261 is secured. The buffer RAM 26 also secures an area in which a copy of the track alternative management information stored in the system area 113 of the disk 11 is stored as a track alternative management table 262 when the HDD is initialized. Normally, the track substitution management table 262 on the buffer RAM 26 is used because of the high speed of access. The track substitution management information in the system area 113 is, for example, H
When the power of the DD is shut off, the contents of the truck substitution management table 262 are updated.

FIG. 2A shows the second track pitch area 112 on the disk 11, which is applied to the HDD of FIG.
3 is a conceptual diagram for explaining the relationship between the servo burst pattern and head positioning in FIG. In FIG. 2 (a),
The outer peripheral direction of the disk 11 is above the paper surface, and the inner peripheral direction is below the paper surface. The disk 11 rotates from the right side of the drawing to the left side of the drawing as indicated by an arrow X in the figure.

As described above, the servo data including the track code and the servo burst pattern is recorded in each servo area 110 of the disk 11. The servo burst pattern is composed of servo burst signals A, B, C and D as position error signals used for head positioning.

In FIG. 2A, burst signals A,
B, C, and D are shifted in the disk radial direction (vertical direction in the drawing) by 1 / n (n is an integer) of the reference track pitch TP1 in the order of A, C, B, and D, and the disk circumferential direction ( A predetermined length L is recorded in the left-right direction in the drawing. Figure 2
In the example of (a), n = 3. Reference track pitch T
There is a fixed relationship between P1 and the length W of the burst signals A, B, C, D in the disk radial direction, that is, TP1 = 3W / 2.

In FIG. 2A, next to the burst signal A recorded with the length L, the burst signal B is 2/3 of the reference track pitch TP1 from the burst signal A on the inner circumference side of the disc (in the figure). On the lower side), a length L is recorded behind the burst signal A by a length L in the circumferential direction of the disk (on the right side of the drawing). Next to the burst signal B, the burst signal C is inwardly of the burst signal A by ⅓ of the reference track pitch TP1, and by the length L backward in the circumferential direction with respect to the burst signal B. It is recorded in. Next to the burst signal C, the burst signal D is on the inner circumference side of the burst signal A by the reference track pitch TP1 and is L in the circumferential direction with respect to the burst signal C.
It is recorded with the length L only backward. The next burst signal A is the reference track pitch TP from the previous burst signal A.
It is recorded at the same circumferential position as the previous burst signal A on the inner peripheral side by 4/3 of 1. Thereafter, the burst signals B, C and D are recorded by the same repetition as described above. Here, the reference track pitch TP1 is 3 of the length W of the burst signals A, B, C, D in the disk radial direction as described above.
It is set to / 2 times and is set to a value slightly wider than the width of the recording head 122 (track width TW), for example, a value wider than about 20%.

The arrangement of the servo burst patterns in the second track pitch area 112 on the disk 11 described above is the same as the arrangement of the servo burst patterns in the first track pitch area 111 whose track pitch is TP1. That is, in this embodiment, similar to the arrangement of the servo burst patterns in the conventional technique shown in FIG. 2B, the servo burst patterns of the same shape and the same size are zigzag over the entire servo area 110 of the recording surface of the disk 11. It is recorded uniformly in a grid pattern.

The CPU 21 reads / writes the IC 18 in response to the burst timing signal from the gate array 19.
Head positioning control for positioning the head 12 on the target track is performed based on the burst signals A, B, C, and D extracted by. This head positioning control differs depending on which of the first track pitch area 111 and the second track pitch area 112 is targeted.

First, the first head positioning control for positioning on the target track on the first track pitch region 111 will be described. This first head positioning control is the same as the head positioning control in the conventional technique shown in FIG. Therefore, the first head positioning control will be described with reference to FIG.

When positioning the head 12 at the head position # 1 in FIG. 2B by servo control using the servo burst pattern, the CPU 21 tracks the boundary between the burst signals A and B along the disk circumferential direction. The center of the track is the playback head 121 of the head 12 as the center.
The VCM 15 of the actuator 14 to which the head 12 is attached is set to the driver I so that the center of the recording head 122 (for reading) or the recording head 122 (for writing) passes through.
Control via C16. Specifically, the positioning of the head 12 is controlled based on the calculation result of (AB) / (A + B) using the level values A and B of the burst signals A and B extracted by the read / write IC 18.

Further, the CPU 21 controls the head 12 as shown in FIG.
In the case of positioning at the head position # 2 in (b), the track center is the boundary between the burst signals C and D along the disk circumferential direction, and the track center is the reproducing head 121 (for reading) or recording. Head 122
Control so that the center of (in the case of writing) passes. Specifically, the level values C and D of the burst signals C and D extracted by the read / write IC 18 are used (DC).
The positioning of the head 12 is controlled based on the calculation result of / (D + C).

Further, the CPU 21 sets the head 12 in FIG.
In the case of positioning at the head position # 3 in (b), the boundary between the next burst signals A and B along the disk circumferential direction is controlled with the track center. The following is a similar repetition.

When the head 12 is positioned by such a method, the track pitch TP1 is larger than the track width TW.
Since (= 3W / 2) is set slightly wider, a guard band corresponding to the difference is secured between tracks on which signals are actually recorded and reproduced.

The effect of this guard band will be described with reference to FIG. The head 12 floats the disk 11 at a predetermined floating distance FS when the disk 11 is rotating at a steady rotation speed. The magnetic flux F generated from the recording head 122 as a recording element of the head 12 has a property of spreading when it goes out into space. For this reason, at the position where the magnetic flux F reaches the disk 11, the magnetic flux F is generated by the recording head 12.
It is wider than the width HW of 2. Therefore, the disk 11
The width 31 of the track recorded above is wider than the width HW of the recording head 122. Therefore, in the conventional technique, the pitch of adjacent tracks, that is, the track pitch (reference track pitch) TP1 is set slightly wider than the width HW of the recording head 122, for example, by about 20%, so that the decrease in the track density is minimized. It is designed so that a guard band is secured between the recorded track and the adjacent track so that the adjacent tracks do not interfere with each other while suppressing the limit.

However, the spread of the magnetic flux F emitted from the recording head 122 to the space depends on the magnitude of the current (write current) applied to the head 12, and the spread increases as the write current increases. In this case, as shown in FIG. 4B, the track width 42 recorded on the disk 11 becomes wider than the normal track width 41, and interferes with the adjacent tracks already recorded on the disk 11. Resulting in. That is, the width of the guard band shown in FIG. 2B may not be useful when the write current becomes excessive.

Generally, when the environmental temperature of the HDD becomes low,
A large change in magnetic field is required to change the magnetic characteristics of the disk 11 and reverse the magnetization. So CPU21
Controls the head IC 17 according to the environmental temperature detected by the temperature sensor 24, and as the temperature is lower, the writing capability (magnetic flux density) of the recording head 122 is increased, so that a larger writing current is applied to the head 12. To supply. However, as described above, when the write current increases, the spread of the magnetic flux increases, which may affect adjacent tracks. This problem can similarly occur even at high temperatures where the "bleeding" of the magnetized portion becomes large.

In addition, a positioning error of the head 12 occurs due to some disturbance such as vibration or shock to the HDD, and the position of the recording head 122 shifts from the original position 51 shown by the broken line in FIG. 5B to the position 52 shown by the solid line. If it does, the position of the recorded track deviates from the original track position 53. In this case, even if the width 54 of the track to be recorded does not widen, there is a risk of interference with the adjacent track. That is, the width of the guard band shown in FIG. 2B may not be useful if the recorded track position is displaced due to some disturbance.

Therefore, in the present embodiment, the track pitch is widened, that is, the guard band is widened as compared with FIG. 2B, while using the same servo burst pattern row as that of the prior art shown in FIG. 2B. The second track pitch region 112 capable of performing the above is secured on the disk 11. Then, when there is a possibility that the width of the track actually recorded on the disk 11 may be widened or there is a possibility that the position of the recorded track may shift, writing to the second track pitch region 112 is performed. By doing
The influence of the writing on the recorded adjacent track or the adverse effect of the adjacent track, that is, the possibility of interference with the adjacent track is minimized.

The second head positioning control for positioning on the target track on the second track pitch region 112 will be described below with reference to FIG. CPU2
When the head 12 is positioned at the head position # 1 in FIG. 2 by servo control using the servo burst pattern, the track center is the boundary between the burst signals A and B along the disk circumferential direction. The actuator 1 in which the head 12 is attached so that the center of the reproducing head 121 (for reading) or the recording head 122 (for writing) of the head 12 passes through
The VCM 15 of No. 4 is controlled via the driver IC 16.

Next, the CPU 21 moves the head 12 to the position shown in FIG.
When positioning at head position # 2 in (a), burst signal A used for positioning at head position # 1,
The boundary between the next burst signals A and B, which is deviated by 2 W in the inner circumferential direction of the disc from B, along the circumferential direction of the disc is the track center, and the track center is the reproducing head 121 (for reading) or recording of the head 12. Head 122
Control so that the center of (in the case of writing) passes.

Further, the CPU 21 controls the head 12 in FIG.
When positioning at head position # 3 in (a), burst signal A used for positioning at head position # 2,
The boundary between the next burst signals A and B along the disc circumferential direction, which is deviated by 2 W from the B in the disc inner circumferential direction, is controlled with the track center. The following is a similar repetition.

As described above, the CPU 21 skips one burst signal pair more than the case of FIG. 2B, that is, skips one third of the reference track pitch TP1 and positions the head 12. I do.

When the head 12 is positioned by such a method, as compared with the case where the pair of burst signals A and B and the pair of burst signals C and D are repeatedly positioned as shown in the prior art. , The track pitch TP2 is (2W-3W / 2) from the reference track pitch TP1, that is, W
It can be set wider by / 2. In other words,,
The track pitch TP2 is set to 1 of the reference track pitch TP1.
It can be set wide by / 3 pitch, and the guard band can be set wide by ⅓ pitch of the reference track pitch TP1.

Therefore, in this embodiment, the head I is controlled by the CPU 21 in order to increase the writing capability of the recording head 122 at a low temperature where recording becomes difficult.
Even if an excessive write current that may increase the recording track width from C17 is applied to the recording head 122, it is possible to prevent interference with adjacent tracks as shown in FIG. 4A. Becomes On the other hand, in the prior art, since the guard band is narrow, when the write current is extremely increased, the recording track width increases due to the spread of the magnetic flux F, which causes interference with the adjacent track as shown in FIG. 4B. Occur. For this reason, conventionally, there is an upper limit to the correction of the write current.

Further, in the present embodiment, even when the position of the recording head 122 is displaced from the original position 51 shown by the broken line in FIG. Since the band is wide, it is possible to prevent interference with adjacent tracks.

As described above, in the present embodiment, by enlarging the guard band, the recording track width is increased (at low temperature or high temperature) due to the spread of the magnetic flux from the recording head 122, etc. It is possible to effectively prevent the interference or the interference with the adjacent track due to the displacement of the head due to the disturbance.

Usually, in order to expand the guard band,
When recording a servo burst pattern by the head, it is necessary to widen the track pitch and increase the feed pitch of the head. On the other hand, in the present embodiment,
The width of the guard band can be increased by ⅓ of the reference track pitch simply by changing the control program for head positioning while using the conventional servo burst pattern. Therefore, there is a feature that the width of the guard band can be selected without changing the manufacturing equipment.

Here, in seek / positioning control of the head 12 according to a write command from the host system,
A specific procedure for deciding which of the area 111 or the area 112 on the disk 11 to write data will be described with reference to the flowchart of FIG.

The CPU 21 first reads the environmental temperature of the HDD measured by the temperature sensor 24 (the output voltage of the temperature sensor 24 representing the environmental temperature of the HDD) via an A / D converter (not shown), and reads the temperature (measurement Temperature) is compared with a predetermined threshold value # 1 (low temperature side reference temperature) (step S1). If the measured temperature is not lower than the threshold # 1, the CPU 21 sets the measured temperature to the predetermined threshold # 1.
2 (high temperature side reference temperature) (step S2). Between this threshold # 2 and threshold # 1, threshold # 2> threshold # 1
Have a relationship. If the measured temperature is not higher than the threshold # 2, that is, the measured temperature is threshold # 1 ≦ measured temperature ≦ threshold #
If it is within the range of 2, the CPU 21 determines that the ambient temperature is in a normal state in which the width of the recording track does not extend to the adjacent track.

In this case, the CPU 21 uses the acceleration sensor 25
The acceleration (i.e., the output voltage of the acceleration sensor 25 indicating the vibration or the shock) indicating the vibration or the shock applied to the HDD due to the disturbance or the like, which is measured by, is read through the A / D converter, and the predetermined threshold value # 3 is read. It is compared with (reference acceleration) (step S3). If the measured acceleration is not higher than the threshold value # 3, the CPU 21 determines that the disturbance applied to the HDD is in a normal state in which the recording track position does not shift to the adjacent track. In this case, CPU2
1 performs the above-mentioned first head positioning control for the track on the first track pitch area 111 designated by the write command from the host system, and writes data to the designated track ( Step S
4).

On the other hand, when the measured temperature is lower than the threshold value # 1 or higher than the threshold value # 2, or when the measured acceleration is lower than the threshold value # 3, that is, when the HDD is in a specific state, The CPU 21 searches for and allocates an empty track on the second track pitch area 112 as an alternative destination of the designated track on the first track pitch area 111, and registers it in the track alternative management table 262 (steps S5 and S6). Then, the CPU 21 performs the above-described second head positioning control on the track on the second track pitch area 112 assigned as the alternative destination, and writes data to the alternative destination track (step S7). .

In this way, the second track pitch region 1
12 is written to the alternative destination track, the track alternative management table 262 is read when the host system issues a command to read the specified track on the first track pitch area 111. By referring to the substitute destination track of the designated track, the substitute destination track is correctly accessed. Further, when returning to the environment where writing to the first track pitch area 111 is performed, the data of the alternative destination track is written back to the corresponding track on the first track pitch area 111 according to the track alternative management table 262. It is also possible to update the track substitution management table 262 so that the designated track becomes an empty track.

In the above description, the track pitch T
Although only the pair of burst signals A and B is used for the head positioning control for realizing P2, the same effect can be obtained by using only the pair of burst signals C and D.

<Modification> Next, a modification of the present embodiment will be described with reference to the conceptual diagram of FIG. 7 corresponding to FIG. In FIG. 7, as in FIG. 2, the outer peripheral direction of the disk 11 is above the paper surface and the inner peripheral direction is below the paper surface. The disk 11 rotates from the right side of the drawing to the left side of the drawing as indicated by an arrow X in the figure.

The feature of this modification is that the track pitch TP2 in the second track pitch region 112 is made wider than that in the above embodiment.

In this modification, as is clear from FIG.
Similar to the arrangement of the servo burst patterns in the conventional technique (first track pitch area 111) shown in FIG. 2B, the servo bursts of the same shape and the same size over the entire servo areas 110 on the recording surface of the disk 11. A configuration is applied in which the pattern is recorded uniformly in a zigzag pattern.

The CPU 21 responds to the burst timing signal from the gate array 19 by the read / write IC 18
Head positioning control for positioning the head 12 on the target track is performed based on the burst signals A, B, C, and D extracted by. Here, the first head positioning control for positioning on the target track on the first track pitch region 111 is the same as the first head positioning control applied in the above embodiment. On the other hand, the second positioning for the target track on the second track pitch region 112 is performed.
The head positioning control of No. 2 is applied to the second embodiment applied in the above embodiment.
Different from the head positioning control of.

Therefore, the second head positioning control different from the above embodiment will be described below. CPU21
When the head 12 is positioned at the head position # 1 in FIG. 7 by the servo control using the servo burst pattern, the track center is the boundary between the burst signals A and B along the disk circumferential direction. As the center of the reproducing head 121 (for reading) or the recording head 122 (for writing) of the head 12 passes through,
The VCM 15 of the actuator 14 to which the head 12 is attached is controlled via the driver IC 16.

Next, when positioning the head 12 at the head position # 2 in FIG. 7, the CPU 21 uses the burst signals C and D corresponding to the pair of burst signals A and B used for positioning at the head position # 1. Pair, that is, head position # 1
W / 2 minutes (track pitch TP1
A pair of burst signals C and D deviated from each other by 1/3 pitch), and a pair of next burst signals C and D on the inner circumference side, that is, a burst signal A used for positioning at head position # 1. , B of the burst signals C and D shifted by 5 W / 2 (5/3 pitch of the track pitch TP1) in the inner circumferential direction of the disc, the burst signals C and D are used.
Control is performed with a boundary along the disk circumferential direction between and as the track center.

Next, when the head 12 is positioned at the head position # 3 in FIG. 7, the CPU 21 pairs the burst signals A and B next to the burst signals A and B used for positioning at the head position # 1. And the next pair of burst signals A and B on the inner circumference side, that is, the pair of burst signals A and B used for positioning at the head position # 1, is 5 W in the inner circumference direction of the disk (track pitch TP1. Of 10/3
A pair of burst signals A and B deviated by the pitch) is used, and control is performed with the boundary between the burst signals A and B along the disk circumferential direction as the track center. The following is a similar repetition.

As described above, the CPU 21 positions the head 12 by skipping two burst signal pairs more than the case of FIG. 2B, that is, by skipping an extra 2/3 pitches of the reference track pitch TP1. I do.

When the head 12 is positioned by such a method, the track pitch TP2 is set to the reference track in comparison with the positioning performed by repeating only the pair of burst signals A and B as applied in the above embodiment. Pitch TP
The width can be set wider by 1/3 pitch of 1 (wider by 2/3 pitch with respect to the reference track pitch TP1), and the guard band can also be set wider by 1/3 pitch.

In the embodiment described above, the disk 11
Each recording surface of is recorded concentrically into a first track pitch region 111 having a high track density and a second track pitch region 112 having a low track density, and it is necessary to correct to a large write current. Specification at the time of low temperature where the track width may widen, or at high temperature when the recording track width may widen due to the effect of the temperature itself, or the positioning error may increase due to disturbance such as vibration and the recording track position may shift significantly. It is assumed that the writing for the second track pitch region 112 is performed only under the conditions and the writing for the first track pitch region 111 is normally performed, but the present invention is not limited to this.

For example, the second track pitch region 112
The area corresponding to is divided into a plurality of areas 112 'in a concentric pattern and set so as to have a pitch larger than the first track pitch and different from each other, and is set as a writing target depending on the ambient temperature or the degree of disturbance ( It is also possible to switch and use the area 112 ′ (which is the target of track substitution). By doing so, it is possible to minimize the reduction in the storage capacity of the disk 11 as a whole due to the increase in the track pitch.

It is also possible to set the entire recording surface of the disk 11 as the second track pitch area 112 so that the HDD is always used in the second head positioning control mode. Since such an HDD is used in a state in which the track density of the entire recording surface of the disk 11 is reduced, the HDD may not be used under the above-mentioned specific conditions, or even for rare users. Is not preferable because it only reduces the storage capacity of the entire disk. Therefore, the entire recording surface of the disk 11 is set as the first track pitch region 111, and the first mode in which the first head positioning control is always performed, and the entire recording surface of the disk 11 is the second recording area. Is set as the track pitch area 112 of the HDD, and any one of the second modes in which the second head positioning control is always performed is set when the HDD is shipped or sold.
Alternatively, the user himself / herself may be configured to be selectively set according to the usage environment of the user. As a result, even if the HDDs are of the same type, by changing the settings (modes), it is possible to provide an HDD that suits the user's usage environment. Here, the mode can be set by storing the mode information in a non-volatile memory such as a flash memory or using a switch.

Further, instead of dividing each recording surface of the disk 11 into a first track pitch area 111 having a high track density and a second track pitch area 112 having a low track density, that is, each recording surface of the disk 11 respectively. Instead of decreasing the track density of a partial area of the disk 11, the track density may be decreased only in a partial area of one recording surface of the disk 11. Further, in an HDD provided with a plurality of disks 11, for example
For only one sheet, the track density may be reduced only in a partial area of at least one recording surface.

Further, in the above-described embodiments, the amount by which the burst signals A, B, C and D are shifted in the disk radial direction is such that the division number n of the track pitch TP1 is 3 and the track pitch TP1 is 1 pitch. Although the pitch is ⅓ of that in the case, if n is an integer of 2 or more, it can be similarly applied.

Further, although the temperature sensor 24 and the acceleration sensor 25 are provided in the magnetic disk device in the above-described embodiments, they may be provided in the host system. Further, instead of using the acceleration sensor 25, the CPU 21 determines whether or not the positioning accuracy is lower than the reference accuracy based on the positioning error information when positioning the head 12 on the target track, and the positioning accuracy is lowered. In such a case, writing may be performed on the second track pitch region 112.

Further, in the above-mentioned embodiments, the case where the present invention is applied to the HDD (magnetic disk device) has been described, but the present invention is not limited to this, and the present invention is applicable to disk storage such as a magneto-optical disk device. It is also applicable to devices.

The present invention is not limited to the above-mentioned embodiment, and can be variously modified at the stage of implementation without departing from the scope of the invention. Furthermore, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem described in the section of the problem to be solved by the invention can be solved, and the effect described in the section of the effect of the invention can be solved. If you get
A configuration in which this component is deleted can be extracted as an invention.

[0087]

As described in detail above, according to the present invention, while using a disc on which a servo burst pattern for realizing a predetermined track pitch is recorded, for example, in a specific area on the disc, the track pitch is Spread out
The track pitch can be set to be sufficiently wider than the track width for writing data. As a result, the guard band expands.Therefore, by writing data to a wide track pitch area at low temperatures or when positioning is poor due to disturbance, the influence of adjacent tracks due to an increase in write current at low temperatures and positioning error Can reduce the effect on adjacent tracks due to

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 compares the relationship between the servo burst pattern and the head positioning in the second track pitch area 112 on the disk 11 applied to the HDD of FIG. 1 with the relationship between the servo burst pattern and the head positioning in the conventional technique. A conceptual diagram for explaining.

FIG. 3 is a diagram for explaining the effect of a guard band.

FIG. 4 is a diagram for explaining the effect of a guard band in the case where the width of a track to be recorded is increased as a result of the spread of magnetic flux due to an increase in the current applied to the head 12, as compared with the related art.

FIG. 5 is a diagram for explaining the effect of the guard band when the position of the recording head 122 is displaced from the original position due to disturbance, in comparison with the related art.

FIG. 6 shows the disk 11 in seek / positioning control of the head 12 according to a write command from the host system.
6 is a flowchart for explaining a procedure for determining whether to write data in the upper area 111 or the upper area 112.

7 is a conceptual diagram for explaining a modified example of the relationship between the servo burst pattern and the head positioning in the second track pitch area 112 on the disk 11, which is applied to the HDD of FIG.

[Explanation of symbols]

11 ... Disc 12 ... Head 14 ... Actuator 15 ... VCM (voice coil motor) 21 ... CPU 22 ... ROM 24 ... Temperature sensor 25 ... Acceleration sensor 110 ... Servo area 111 ... First track pitch region 112 ... Second track pitch region 113 ... System area 121 ... Playback head 122 ... recording head 262 ... Truck alternative management table

Claims (8)

[Claims] 1. At least one disk, and a head provided corresponding to each recording surface of the disk for writing data to the disk and reading data from the disk, On each recording surface of the disk, a row of the same servo burst pattern, which is a servo burst pattern used for positioning the head on a target track and is composed of a plurality of burst signal pairs having mutually different phases, is formed. In a disk storage device in which recording is performed radially in a radial direction of the disk and at equal intervals in a circumferential direction of the disk, and a first track pitch can be realized, at least one recording surface of at least one disk. A ring set to have a second track pitch larger than the first track pitch. , A specific area used to replace a track on another area is secured in advance, and writing to a target track on the disk causes interference with an adjacent track. A means for predicting that, a means for allocating an arbitrary track on the specific area as an alternative destination of the target track according to a prediction result of the prediction means, and a head positioning means for positioning the head on the target track. When the head is positioned on the alternative destination track on the specific area allocated by the allocation means, the burst signal pair used for positioning is set so that the track pitch of the specific area becomes the second track pitch. A disk storage device comprising: head positioning means for selecting. 2. The target track is further provided with means for varying a write current supplied to the head according to an environmental temperature of the apparatus, wherein the allocating means has the target track when the environmental temperature is lower than a low temperature side reference temperature. 2. The disk storage device according to claim 1, wherein an arbitrary track on the specific area is assigned as an alternative destination of. 3. The allocating means allocates an arbitrary track on the specific area as an alternative destination of the target track when the environmental temperature is higher than a high temperature side reference temperature. Disk storage device. 4. The allocating means allocates an arbitrary track on the specific area as an alternative destination of the target track when the disturbance applied to the device exceeds a reference value. The disk storage device described. 5. The apparatus further comprises means for detecting that the positioning accuracy is lower than a reference accuracy based on positioning error information when positioning the head on a target track, and the assigning means determines the positioning accuracy. 2. The disk storage device according to claim 1, wherein when it is detected that the accuracy is lower than the reference accuracy, an arbitrary track on the specific area is assigned as an alternative destination of the target track. 6. At least one disk, and a head provided corresponding to each recording surface of the disk for writing data to the disk and reading data from the disk, On each recording surface of the disk, a row of the same servo burst pattern, which is a servo burst pattern used for positioning the head on a target track and is composed of a plurality of burst signal pairs having mutually different phases, is formed. In a disk storage device in which recording is performed radially in a radial direction of the disk and at equal intervals in a circumferential direction of the disk, and a first track pitch can be realized, at least one recording surface of at least one disk. Includes a second track pitch larger than the first track pitch and different from each other. A plurality of ring-shaped specific areas that are set so that a plurality of specific areas that are used to substitute tracks on other areas are secured in advance, and data for the target track on the disk Means for predicting the occurrence of interference between adjacent tracks due to writing and the degree of the interference, and the plurality of specific areas according to the predicted degree of the interference based on the prediction result of the prediction means. And means for assigning an arbitrary track on the selected specific area as an alternative destination of the target track, and head positioning control means for positioning the head on the target track by the assigning means. When the head is positioned on the alternative destination track on the assigned specific area, the track pitch of the specific area is unique to the specific area. A disk storage device comprising head positioning means for selecting the burst signal pair used for positioning so as to have a second track pitch. 7. At least one disk, and a head provided corresponding to each recording surface of the disk for writing data to the disk and reading data from the disk, On each recording surface of the disk, a sequence of the same servo burst pattern, which is a servo burst pattern used to control the positioning of the head on a target track, and is composed of a plurality of burst signal pairs different in phase from each other. Are recorded in a radial direction of the disc and at equal intervals in the circumferential direction of the disc, and the first track pitch can be realized in the disc storage device, wherein the disc is used at the first track pitch. The first mode or the second track pitch larger than the first track pitch A second mode to be used is a mode holding unit that is preset and selected, and a head positioning unit that positions the head on a target track. When the second mode is set in the mode holding unit, the track A disk storage device, comprising: head positioning means for selecting the burst signal pair used for positioning so that the pitch becomes the second track pitch and positioning the head. 8. At least one disk, and a head provided corresponding to each recording surface of the disk for writing data to the disk and reading data from the disk, A servo burst pattern used to position the head in a target track on each recording surface of the disk,
A row of the same servo burst pattern composed of a plurality of burst signal pairs different in phase from each other is recorded radially in the radial direction of the disk and at equal intervals in the circumferential direction of the disk, and at least one disk is formed. A ring-shaped specific area set to have a second track pitch larger than a first track pitch that can be realized by the row of the servo burst patterns on at least one recording surface of the disk, A head positioning method in a disk storage device in which a specific area used for replacing a track on another area is secured in advance, and when a write request to the disk is given from a host system, the write request Interference with adjacent tracks occurs when data is written to the track on the disk specified by If it is predicted that interference between adjacent tracks will occur, an arbitrary track on the specific area as an alternative destination of the track on the disk designated by the write request. Allocating the burst signal pair used for positioning so that the track pitch of the specific area becomes the second track pitch when positioning the head on the alternative destination track on the allocated specific area. And a step of positioning the head by selecting.