JPH06309821A - Magnetic disk device and servo control method - Google Patents

Abstract

PURPOSE:To minimize the reduction of a data recording capacity of a device, to increase the precision in positioning of a magnetic head and also to enlarge the recording capacity by providing a section for second servo information containing a part of first servo information between sections for the first servo information. CONSTITUTION:Between a section for first servo information and a subsequent section for the first servo information, another section for second servo information is provided. In this section for the second servo information, a part of positional information out of various information contained in the first servo information is provided and, besides, burst AGC data working in the same way as address AGC data contained in the first servo information are provided before the positional information. In this constitution, servo areas 100 for recording the first servo information are also provided at a prescribed interval for each track in a track format and a space between these areas 100 is used as a user area 300, while a servo area 200 for recording the second servo information is provided between the areas 100. In the area 100, areas 101 to 104 for address AGC, erase, a cylinder address, the positional information, etc., are provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a disc (recording medium).
The present invention relates to a data surface servo type magnetic disk device and a servo control method for performing positioning control of a magnetic head on the basis of servo information recorded on the data recording surface.

[0002]

2. Description of the Related Art Conventionally, in a magnetic disk device, a magnetic head is positioned at a target track and data is recorded or reproduced by using a data surface servo system such as a set servo. The data surface servo system is a system in which servo information required for positioning control of the magnetic head is recorded in advance on the data recording surface of the disk.

In a magnetic disk drive using such a data surface servo system, cylinder (track) address information indicating the current position of the magnetic head and the center of the track of the magnetic head are recorded for each servo area arranged on the track. Servo information including position information (burst information) for obtaining the position error information indicating the amount of positional deviation is given to the CPU through the servo control circuit. The CPU calculates the current value to be supplied to the voice coil motor (hereinafter referred to as VCM) based on this servo information. The VCM is a motor for driving the carriage. The magnetic head is supported by the tip of this carriage and moves in the radial direction of the disk via the carriage by the driving force of the VCM.

[0004]

As described above, in the data surface servo system, servo information is obtained for each servo area, and the VCM is driven based on the servo information. In this case, the constant current is VCM during the period when the servo information is not obtained, that is, from the servo area to the next servo area.
To be supplied to. Therefore, during this period, even if the magnetic head is abnormally accelerated due to disturbance or the like, a constant current is supplied to the VCM without any correction.

As described above, the data surface servo system has a problem that the positioning accuracy of the magnetic head is low because the servo information is obtained only intermittently. In this case, if the number of servo areas arranged in one track is increased, the sampling interval of servo information is shortened, the positioning accuracy of the magnetic head is improved, and even if the magnetic head is displaced from the target track due to disturbance or the like, The sensitivity to detect it becomes high.

However, since a large amount of information such as cylinder address information and position information is recorded as servo information in the servo area, if the servo area is simply increased, the data area in one track will be increased accordingly. However, there is a problem that the data recording capacity of the device is reduced.

The present invention has been made in view of the above points, and in the data surface servo system, it is possible to minimize the decrease in the data recording capacity of the device and improve the positioning accuracy of the magnetic head. An object is to provide a disk device and a servo control method.

[0008]

In a magnetic disk drive of the present invention, a plurality of concentric tracks are provided, and a plurality of first servo information are recorded at predetermined intervals on each track. Between the first servo information, the first
Magnetic recording medium on which the same information as a part of the servo information is recorded as second servo information, head means for recording / reproducing information on / from this magnetic recording medium, and the head means for supporting the head means. Based on the carriage means for moving the recording medium in the radial direction and the first and second servo information read from the magnetic recording medium by the head means, the head means is positioned on a target track. And a control means for controlling the carriage means.

[0009]

According to the above arrangement, the head means reads the first and second servo information from the magnetic recording medium,
Positioning control is performed based on these servo information,
The head means will be positioned at the center of the target track.

In this case, since the second servo information is provided between the first servo information, the opportunity to detect the off-track amount (deviation amount from the track center) of the head means increases, and as a result, The positioning accuracy can be improved. Moreover, since the second servo information is composed of a part (at least the position information) of the first servo information,
As compared with the case where a large number of first servo information are arranged on the track, the reduction in the data recording capacity of the device can be suppressed to the minimum.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The present invention is characterized by a method of recording servo information in a data surface servo type magnetic disk device. First, the servo information recording method will be described with reference to FIGS.
Will be described with reference to.

FIG. 1A is a diagram showing the structure of a recording medium according to an embodiment of the present invention. A plurality of tracks are concentrically provided on the data recording surface 1a of the disc 1 (recording medium). Normally, servo information (hereinafter referred to as first servo information) necessary for magnetic head positioning control is intermittently provided for each track. The area delimited by the first servo information becomes a sector. The first servo information is address AGC data for absorbing fluctuations in output amplitude, sync detection data for creating a sync signal (reference signal) necessary to start servo processing, and a track start position (index). ) Or an index / sector code indicating a non-leading position (sector), a cylinder address code indicating the current position, and position information for obtaining position error information indicating the amount of displacement of the magnetic head from the center of the track. Among them, the position information is composed of a plurality of burst data A to D as shown in FIG.

In this embodiment, another servo information (hereinafter referred to as second servo information) is provided between the first servo information and the next first servo information. The second servo information is provided with a part of position information (here, two types of burst data A and B as shown in FIG. 4) of each information included in the first servo information. ing. Further, here, before this position information, burst AGC data having the same function as the address AGC data in the first servo information is provided.

FIG. 1B is a diagram showing the structure of the track format of the embodiment. In the figure, 100 is the above-mentioned first
This is a servo area for recording the servo information of. The servo areas 100 are provided at predetermined intervals for each track, and the areas between the servo areas 100 are data areas (user areas) 300. Further, 200 is a servo area for recording the above-mentioned second servo information. This servo area 200 is the servo area 100
It is provided in between.

FIG. 1C is a diagram showing the structure of the servo area 100. Servo area 100 has address AGC
An area 101, an erase area 102, a cylinder address code area 103, and a position information area 104 are provided, and each area includes information (address AGC data, sync detection data, index / sector code, cylinder). Address code and position information) are recorded respectively.

This state is shown in FIGS. 2 and 3. In the address AGC area 101, address AGC data for absorbing fluctuations in output amplitude is recorded. Erase data is recorded in the erase area 102. The erase detection data and the synchronization detection code in the cylinder address code area 103 form synchronization detection data. In the cylinder address code area 103, the cylinder address code (A10 in the figure) indicating the current position is displayed.
~ A0) is recorded. At the head of the cylinder address code area 103, a sync detection code (I0 in the figure) used for detecting the sync signal together with the above-mentioned erase data, and the head position (index) or non-head position (sector) of the track. An index / sector code (I1, I2 in the figure) indicating is recorded.

In the position information area 104, GAP AG
Position information composed of C data, four types of burst data indicated by A to D, and GAP burst data is recorded. Of these, the burst data A to D are ½ in the radial direction of the disk from the center position of each track.
It is recorded by shifting tracks.

FIG. 1D is a diagram showing the structure of the servo area 200. Servo area 200 is burst AGC
The servo area 200 has an area 201 and a position information area 202, and burst AGC data and position information forming the second servo information are recorded in the servo area 200.

This state is shown in FIG. The burst AGC area 201 has an address A in the first servo information.
Burst AGC data having the same function as the GC data is recorded. In the position information area 202, position information composed of burst data A, burst data B and GAP burst data is recorded. Of these, the burst data A and B are recorded by being shifted by 1/2 track in the radial direction of the disk from the center position of each track.

Here, illustration of the magnetization direction of the recorded data is omitted. The solid vertical line indicates the magnetization reversal position of the recorded data. Next, the circuit configuration of the embodiment will be described.

FIG. 5 is a block diagram showing the basic structure of the magnetic disk device. In FIG. 5, reference numeral 1 denotes a disk as a recording medium, which is rotationally driven by the spindle motor 5. A plurality of tracks are concentrically provided on the data recording surface of the disc 1, and data is recorded / reproduced on the tracks.

Here, the track is divided into small blocks called sectors, and data is recorded / reproduced in units of the sectors. That is, a plurality of sectors are included in the track.

Each track is defined by recording servo information corresponding to each track. Servo information is generally recorded by a specific manufacturing facility during the disk manufacturing process. In order to uniquely identify each track, a track address is assigned to this track based on a physical positional relationship.

As for the data recording surface, it is common to use two front and back surfaces for one disc, and in this case, two identical track addresses exist. The tracks having such a relationship are generically called a cylinder, and strictly speaking, the carriage accesses the cylinder, and the track is selected by designating the head from the cylinder. The same applies when there are a plurality of disks. Similarly, a head number is assigned to each head so that each head can be uniquely specified based on its physical positional relationship.

Reference numerals 2a and 2b are magnetic recording heads for recording / reproducing data. The heads 2a and 2b are
It is attached to the tip of the carriage 3 and moves in the radial direction of the disk 1 (direction crossing the track) via the carriage 3.

Reference numeral 3 is a carriage. This carriage 3
Is equipped with an access motor 4 and is driven by this. In the example of FIG. 5, the carriage 3 swings around the axis shown by the alternate long and short dash line by the driving force of the access motor 4.

Reference numeral 4 is an access motor. The access motor 4 is often a rotary or linear voice coil motor (VCM). 6 is a head control circuit. The head control circuit 6 includes a head selection circuit, a head drive circuit for writing data, a head amplifier for reading data, a write abnormality detection circuit, and the like. Generally, when a write signal is supplied, a drive current is supplied to a selected head to perform data recording, and when a write signal is not supplied, magnetic recording that passes under the selected head. Information is played back and continues to be output.

Reference numeral 7 is an analog signal processor. In the magnetic disk device, the analog signal processor 7 includes an automatic gain control circuit, a filter, a waveform equivalent circuit (equalizer), and the like. When reading data, in order to digitize the recorded information, the waveform of the reproduction signal supplied from the head control circuit 6 is manipulated to increase the reliability of signal detection. Further, the analog signal obtained here is also appropriately manipulated for the servo information portion, reproduced as a position signal, and used for servo control.

Reference numeral 8 is a pulsing circuit for pulsing the signal from the analog signal processor 7. The pulsing circuit 8 includes a differentiating circuit, a filter, a signal comparing circuit and the like.
9 is a data converter. This data converter 9 has P
LL (Phase / Frequency Synchronized Oscillator: Phase Locked Loop
), A signal discrimination circuit, a read data decoding circuit (data decoder), and the like. When a data read instruction is given, the PLL synchronizes the input data with the frequency and phase and creates a data discrimination window. The signal discriminating circuit identifies the read pulse using the created data discriminating window and reproduces the data string in the recording format. The decoder decodes the reproduction data according to a predetermined decoding rule and outputs the result as a signal.

Reference numeral 10 is a serial-parallel converter. Since the signal from the data converter 9 is bit serial data, it is parallelized here and converted into byte format data. The converted byte data is stored in the buffer memory 13. When writing data, it is necessary to convert the data from the host into data in a recording format suitable for magnetic recording. The recording format in this case is, for example, MFM (Modified Frequ
ecy Modulation) method and RLL (Run Length Limited)
The method is well known.

Reference numeral 11 is a parallel-serial conversion circuit. The byte data from the buffer memory 13 is now converted into bit serial data. Reference numeral 12 is a data conversion circuit. The data conversion circuit 12 converts the bit serial data from the parallel-serial conversion circuit 11 according to a predetermined conversion rule, converts this into recording format data, and then transfers it to the head control circuit 6.

Reference numeral 13 is a buffer memory. Data exchange with the host is performed via the buffer memory 13. The data from the host is received at the timing of the host and is temporarily stored in this buffer memory 13. The data thus captured is converted into bit serial data by the parallel-serial conversion circuit 11, converted into recording format data, and recorded on the disc 1. On the other hand, when the host requests data, the read data is stored in the buffer memory 13. Thereafter, the read data is sent from the buffer memory 13 to the host according to the reception timing of the host.

Reference numeral 14 is a disk controller (HDC).
A head control circuit 6, a buffer memory 13, a servo control circuit 15, and a microcontroller 19 are connected to the disk control unit 14. The disk control unit 14 sends and receives data to and from the host and the buffer memory 1
The data writing / reading control for 3 is performed.

Reference numeral 15 is a servo control circuit. The servo control circuit 15 detects the read pulse output from the pulse conversion circuit (A / D converter) 8, creates a reference signal of servo information, and generates a specified data discrimination window based on this reference signal. Then, the servo information is decoded to generate an index / sector signal and an interrupt signal to the microcontroller 19. A sample timing signal for extracting the analog position signal is also generated here and is supplied to the position signal generator 16.

A servo control circuit 15 is connected to the pulse conversion circuit 8. A position signal generator 16 is connected to the servo control circuit 15 and the analog signal processor 7.
The position signal generator 16 outputs from the servo control circuit 15 the amplitude values of the analog read signals corresponding to the burst data A to the burst data D among the analog read signals output from the analog signal processor 7. The sample and hold signal is sampled and held based on the sample timing signal, and is output to the microcontroller 19 as a sample and hold signal. The microcontroller 19
The built-in A / D converter converts the sample hold signal output from the position signal generator 16 into a binary signal.

A filter 18 and a motor drive circuit 17 are connected between the microcontroller 19 and the access motor 4. The signal output from the microcontroller 19 to the filter 18 is a motor control signal for controlling the drive of the access motor 4. Filter 18
Removes the noise of the input motor control signal and outputs it to the motor drive circuit 17. The motor drive circuit 17 drives the access motor 4 based on a motor control signal given from the microcontroller 19 via the filter 18.

A motor control circuit 21 is connected between the microcontroller 19 and the spindle motor 5. The motor control circuit 21 detects the rotational position of the rotor of the spindle motor 5 and supplies the detection signal to the microcontroller 19. Micro controller 19
Outputs a motor control signal for controlling the rotation of the spindle motor 5 to the motor control circuit 21 based on the detection signal of the rotational position of the rotor supplied from the motor control circuit 21. The motor control circuit 21 is the microcontroller 1
The drive of the spindle motor 5 is controlled on the basis of the motor control signal supplied from 9. A memory 20 is connected to the microcontroller 21.

FIG. 6 is a diagram specifically showing mainly the servo system circuit in FIG. The reproduced signals reproduced by the heads 2a and 2b are amplitude / waveform shaped by the head control circuit 6 and the signal processor 7, binarized by the pulsing circuit 8, and then input to the servo control circuit 15 as a read pulse. It

Here, the servo control circuit 15 is composed of an address code detection circuit 15a, a timing generation circuit 15b and a reference clock generation circuit 15c. The address code detection circuit 15a creates a window for reading data based on the reference clock, detects the sync signal for servo processing from the read pulse, and then detects the index / sector signal and the cylinder address code. read out. The timing generation circuit 15b is
The sample signal A to sample signal D, which is a sample timing signal, and the clear signal are sent to the address code detection circuit 15a
It is created based on the synchronization signal output from the device and output to the position signal generator 16. The reference clock generation circuit 15c is
A reference clock in the servo control circuit 15 is generated.

The system bus 40 of the microcontroller 19 has a CPU 30, a memory controller 31, an interrupt controller 32, a D / A converter 36 and A, respectively.
The / D converter 39 is connected. The selection circuit 35 is connected to the D / A converter 36. A sample and hold circuit 33 and a sample and hold circuit 34 are connected to the selection circuit 35. Sample and hold circuit 3
3 is connected to the motor control circuit 21. The sample and hold circuit 34 is connected to the filter 18. The A / D converter 39 includes a sample and hold circuit 3
8 is connected. The sample and hold circuit 38
It is connected to the selection circuit 37. The selection circuit 37 is connected to the position signal generator 16.

These CPU 30, memory controller 31, interrupt controller 32, D / A converter 36, selection circuit 35, sample and hold circuit 33, sample
The hold circuit 34, the A / D converter 39, the sample and hold circuit 38, and the selection circuit 37 constitute a microcontroller 19. This microcontroller 19 is an INTEL CORPORATIO
It can be realized by the LSI (8xC196HD) sold by N.

The position signal generator 16 uses the burst data A ... Of the read signals output from the signal processor 7.
The amplitude value of the read signal corresponding to the burst data D is sample-held on the basis of the sample signal A to sample signal D which are the sample timing signals output from the servo control circuit 15b, and the sample-hold signal A to sample-hold signal. It is output as D to the selection circuit 37 of the microcontroller 19. The micro-controller 19 selects the input sample-hold signal A to sample-hold signal D by the selecting circuit 37 one by one, and outputs them to the sample-hold circuit 38. The sample and hold circuit 38 samples and holds the sample and hold signal A to the sample and hold signal D output from the selection circuit 37, and outputs the sample and hold signal to the A / D converter 39. A / D
The converter 39 binarizes the input sample hold signal.

The address code output from the address code detection circuit 15a is output to the memory controller 31. The memory 20 is connected to the memory controller 31. The sector interrupt signal output from the address code detection circuit 15a is output to the interrupt controller 32.

The motor control signal for the access motor 4 output from the CPU 30 is converted into an analog signal by the D / A converter 36 and then output to the selection circuit 35.
The selection circuit 35 outputs the motor control signal input under the control of the CPU 30 to the sample hold circuit 34. The sample-hold circuit 34 samples and holds the input motor control signal and outputs it to the filter 18.

Similarly, the motor control signal for the spindle motor 5 output from the CPU 30 is converted into an analog signal by the D / A converter 36 and then output to the selection circuit 35. The selection circuit 35 receives the motor control signal input under the control of the CPU 30 and holds the sample and hold circuit 33.
Output to. The sample hold circuit 33 samples and holds the input motor control signal and outputs it to the motor control circuit 21.

Next, the operation of the embodiment will be described. As shown in the flow chart of FIG.
9 starts servo processing in response to a sector interrupt signal from the servo control circuit 15. The microcontroller 19 first reads the cylinder address code in the servo information to confirm the current cylinder position (track position) (step S1). Then, the microcontroller 19 reads the position information in the servo information (step S2).

Next, the microcontroller 19 calculates the distance (remaining distance) from the current cylinder position (track position) confirmed in step S1 to the target track (step S3). The cylinder address code is given from the address code detection circuit 15a.

Next, the microcontroller 19 determines whether the magnetic head is located less than one track (or several tracks) from the target track based on the distance (remaining distance) to the target track calculated in step S3. It is judged (step S4).

As a result of the determination in step S4, when the magnetic head has not reached the position less than one track from the target track, the microcontroller 19 calculates the distance (remaining distance) to the target track calculated in step S3.
A control amount corresponding to the control amount is calculated and a drive current corresponding to the control amount is supplied to the access motor 4 through the motor drive circuit 17 (step S7). Thereby, the heads 2a, 2b
Will seek (move) to the target track on the magnetic disk 1 via the carriage 3.

The control of the movement of the magnetic head according to the distance (remaining distance) to the target track is called speed control. Servo processing is roughly divided into speed control and position control described below. The speed control controls the moving speed of the magnetic head for seeking (moving) the magnetic head to the target track. The position control controls the position of the magnetic head so that the magnetic head is located at the center of the target track.

On the other hand, as a result of the determination in step S4, when the magnetic head reaches the position less than one track from the target track, the microcontroller 19 determines in step S4.
Based on the position information in the servo information read in 2, the position deviation amount indicating how much the position of the magnetic head deviates from the center of the target track is detected (step S5). The position information is given from the position signal generator 16. The operation of the position signal generator 16 will be described later.

Next, the microcontroller 19 calculates a control amount for correcting the position displacement from the center of the target track of the magnetic head according to the position displacement amount obtained in step S5, and this control amount is calculated. Is supplied to the access motor 4 through the motor drive circuit 17 (step S6). As a result, the heads 2a and 2b are
Positioned at the center of the target track.

Positioning the magnetic head at the center of the target track according to the amount of displacement of the magnetic head from the center of the target track is called position control. By the way, in the above-described position control, it is necessary to accurately detect the off-track amount of the magnetic head (positional deviation amount from the center of the target track) using the position information in the servo information.

As shown in the timing chart of FIG.
In the timing generation circuit 15b, when the address code detection circuit 15a detects the synchronization signal, a window signal (sample signals A to D) for sampling each of the burst data A to D forming the position information.
Then, a window signal (sample clear signal) for canceling the previous sample value is created, and these are output to the position signal generator 16.

Here, in the conventional magnetic disk device, the window signal is created once by one servo processing (sector interrupt). In the present embodiment, another servo information (second servo information) having only position information (here, burst data A and B) is provided between the original servo information (first servo information).
(Servo information of 1) is provided, the window signal is created again.

When the sample signals A to D are input to the position signal generator 16 by the detection of the first servo information, the position signal generator 16 holds the waveform amplitude values of the burst data A to D, respectively. , And outputs to the microcontroller 19 via the sample and hold signals A to D. The microcontroller 19 performs the position control as described above by calculating the control amount based on the burst data A to D.

Next, when the second servo information is detected,
The position signal generator 16 first clears the previous hold value by the sample clear signal and then samples and holds only the waveform amplitude values of the burst data A and B again. The microcontroller 19 calculates a correction output value from the waveform amplitude values of the sample and hold signals A and B sample-held at this time, and controls the access motor 4.

In this way, the positioning control is performed based on the first and second servo information, and the heads 2a, 2
b will be positioned in the center of the target track.
In this case, in the conventional magnetic disk device, the microcontroller 19 uses the heads 2a, 2 except for the servo information (first servo information) including the cylinder address code.
The off-track amount of b cannot be known. For this reason,
For example, even when the heads 2a and 2b are abnormally accelerated due to disturbance or the like, the microcontroller 19 continues to supply a constant current to the access motor 4 without any correction until the servo information is detected next time. .

On the other hand, in this embodiment, since the second servo information is provided between the first servo information, the chances of detecting the off-track amount are increased, and as a result, the heads 2a and 2b are detected. The positioning accuracy can be improved.
In this case, since the second servo information is composed only of a part of the first servo information, that is, only the position information, compared to the case where a large number of the first servo information are arranged on the track, It is possible to minimize the decrease in the data recording capacity.

Next, another embodiment of the present invention will be described. FIG. 9 is a diagram showing the structure of a track format according to another embodiment of the present invention. In the figure, 100 is a servo area for recording the first servo information, 200 is a servo area for recording the second servo information, and 300 is a data area (user area) for recording the user data. In the above embodiment, one second servo information is provided between the first servo information, but at least one second servo information is sufficient, and a plurality of second servo information may be provided as shown in FIG. In this case, since there is a problem of the data recording capacity of the device, it is necessary to reduce the first servo information as the second servo information increases.

More specifically, it is assumed that 50 pieces of first servo information are currently provided in a track, for example. This accounts for about 15% of the total storage capacity. If this first servo information is reduced to about 20 and a plurality of second servo information is provided between the first servo information, the data recording capacity of the device is not reduced and the positioning accuracy is also reduced. I won't let you.

FIGS. 10A to 10D are diagrams showing the structure of the second servo information according to another embodiment of the present invention. In the above-described embodiment, the second servo information includes 2 as position information.
Although two burst data A and B are provided, as shown in FIG.
As shown in (a), four burst data A to D may be provided similarly to the position information included in the first servo information.

Further, as shown in FIG. 10B, the second servo information may be provided with a part of the cylinder address code included in the first servo information in addition to the position information. In this case, for example, if the cylinder address code consists of 8-bit data, the lower 4
By providing a bit in the second servo information, it is possible to recognize several cylinders. As a result, the positioning accuracy is further improved.

As shown in FIG. 10C, the second servo information is provided with the sync detection data (the erase data and the sync detection code shown in FIG. 2) included in the first servo information. You can In this case, as shown in FIG. 7, the burst data A and B in the second servo information can be detected by counting from the detection position (synchronization position) of the regular synchronization signal, but especially the rotation fluctuation of the disk In the case where there is a problem, the detection accuracy can be improved by providing the synchronization detection data also in the second servo information.

Further, as shown in FIG. 10D, the second servo information may be provided with part of the above cylinder address code and synchronization detection data in addition to the position information.
However, since there is a problem of the data recording capacity of the device, it is desirable to provide at least only the position information.

Further, in any of the configurations shown in FIGS. 10A to 10D, it is necessary to provide burst AGC data for absorbing the amplitude fluctuation of the output signal of the magnetic head at the head. Further, in the present invention, as the data surface servo system, in addition to the sector servo system in which the same number of sectors are provided at equal intervals for each track, the number of sectors is different for each track.
DR (Constant Density Record)
Ding) method is also applicable.

[0067]

As described above, according to the present invention, the second servo information is provided between the first servo information, and a part of the first servo information (at least the position information is included in the second servo information). ) Is provided, it is possible to minimize the decrease in the data recording capacity of the device and improve the positioning accuracy of the magnetic head. As a result, in the data surface servo type magnetic disk device, it is possible to realize a device that satisfies both the data recording capacity and the positioning accuracy of the device.

[Brief description of drawings]

1A is a diagram showing a configuration of a recording medium according to an embodiment of the present invention, FIG. 1B is a diagram showing a configuration of a track format of the embodiment, and FIG. First of the same embodiment
FIG. 6 is a diagram showing a configuration of a servo area for recording the servo information of FIG. 4, and FIG. 6D is a diagram showing a configuration of a servo area for recording the second servo information of the embodiment.

FIG. 2 is a diagram showing a specific configuration of a servo area (first servo information) shown in FIG. 1 (c).

FIG. 3 is a diagram showing a specific configuration of a servo area (first servo information) shown in FIG. 1 (c).

FIG. 4 is a diagram showing a specific configuration of a servo area (second servo information) shown in FIG. 1 (d).

FIG. 5 is a block diagram showing a circuit configuration of the embodiment.

FIG. 6 is a diagram specifically showing the servo system circuit in FIG. 5 as a center.

FIG. 7 is a timing chart for explaining the operation of the embodiment.

FIG. 8 is a flowchart for explaining the operation of the embodiment.

FIG. 9 is a diagram showing the structure of a track format according to another embodiment of the present invention.

FIGS. 10A to 10D are diagrams showing the configuration of second servo information according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Disk, 2a and 2b ... Head, 3 ... Carriage, 4 ... Access motor, 15 ... Servo control circuit, 16
... Position signal generator, 17 ... Motor drive circuit, 18 ... Filter, 19 ... Micro controller, 15a ... Address code detection circuit, 15b ... Timing creation circuit, 15c
Reference clock generation circuit, 30 CPU, 31 memory controller, 32 interrupt controller, 33 sample hold circuit, 34 sample hold circuit, 3
5 ... Selection circuit, 36 ... D / A converter, 37 ... Selection circuit,
38 ... Sample and hold circuit, 39 ... A / D converter, 4
0 ... System bus, 100 ... Servo area (first servo information), 200 ... Servo area (second servo information), 300 ... Data area, 101 ... Address AGC
Area, 102 ... Erase area, 103 ... Cylinder address code area, 104 ... Position information area, 201
... Burst AGC area, 202 ... Position information area.

Claims (10)

[Claims] 1. A plurality of concentric tracks are provided,
A plurality of first servo information is recorded on each track at a predetermined interval, and the same information as a part of the first servo information is recorded between the first servo information and the second servo information. Magnetic recording medium recorded as servo information, head means for recording / reproducing information on / from this magnetic recording medium, carriage means for supporting this head means and moving it in the radial direction of said magnetic recording medium, and said head Control means for controlling the carriage means so as to position the head means on a target track based on the first and second servo information read from the magnetic recording medium by means. And a magnetic disk device. 2. The first servo information has address information indicating a track position and a plurality of position information for obtaining a position deviation amount from the center of the track of the head means, and the second servo information is The magnetic disk device according to claim 1, wherein the magnetic disk device has the same information as a part of the plurality of position information. 3. The first servo information has address information indicating a track position and a plurality of burst information for obtaining a positional deviation amount from the center of the track of the head means, and the second servo information is 3. The magnetic disk device according to claim 2, wherein the magnetic disk device has the same information as a part of the plurality of burst information. 4. The magnetic disk drive according to claim 2, wherein the second servo information further has a part of the address information. 5. The magnetic disk drive according to claim 3, wherein the second servo information further has a part of the address information. 6. The first servo information has synchronization detection data, address information indicating a track position, and a plurality of position information for obtaining a position shift amount of the head means from the center of the track, and the second servo information. 2. The magnetic disk device according to claim 1, wherein the servo information of the same has the same information as the synchronization detection data and the same information as a part of the plurality of position information. 7. The first servo information has synchronization detection data, address information indicating a track position, and a plurality of burst information for obtaining a positional deviation amount from the track center of the head means, and the second servo information. 7. The magnetic disk device according to claim 6, wherein the servo information has the same information as the same detection data and the same information as a part of the plurality of burst information. 8. The magnetic disk drive according to claim 6, wherein the second servo information further includes a part of the address information. 9. The magnetic disk drive according to claim 7, wherein the second servo information further has a part of the address information. 10. A plurality of concentric tracks are provided,
A plurality of first servo information is recorded on each track at a predetermined interval, and a second servo information having the same information as a part of the first servo information is recorded between the first servo information. A magnetic disk having a magnetic disk on which servo information is recorded, a head means for recording and reproducing data on the magnetic disk, and a carriage means for supporting the head means and moving the magnetic disk on the magnetic disk in a radial direction. In the disk device, the head means reads the first servo information from the magnetic disk, the head means reads the second servo information from the magnetic disk, and the head means reads from the magnetic disk. Based on the first and second servo information, the carriage is positioned to position the head means on a target track. Servo control method characterized by controlling means.