JPH09167457A - Disk device and control method for position of head in disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance by forming a data track in a spiral state with the use of the servo area arranged in the peripheral direction of a disk at every specified space and unnecessitating the seek operation for the movement between tracks in the reading/writing operation for continued data. SOLUTION: The constitution is made in such a manner that the target value of a PES(position error signal) obtained from servo signals which are buried on the track with the specified spaces, is successively changed for realizing the spiral track by reading the PES which is the conventional servo information. In the case of the disk device performing the positional control with the PES obtained from each servo area in the disk which is provided with the servo area of 60 pieces per one round of the disk, when the values available for the PES as the information on each position in the width direction of one track are taken as 256 kinds, the positional control of the head is executed by the value set by succesively shifting the target value of PES for every 256/60 track position in each of 60 servo positions. By such a positional control, the head is moved in accordance with the target PES values different for every servo area, thereby, the spiral track is followed up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data reading / writing format and a servo method in a magnetic disk device. More specifically, in a disk device for positioning a head by servo data embedded at a predetermined interval in a data track of a disk and reading / writing data, a device and method for spirally writing / reading data. Regarding

[0002]

2. Description of the Related Art In a magnetic disk such as a hard disk device, a large number of data tracks are concentrically formed. When data writing or reading is completed on a certain predetermined track and further continuous data reading / writing is performed, the head is moved to an adjacent track and positioned (seek), and data reading / writing is continued. When the data amount is large, the seek operation and the data reading or writing operation are alternately repeated a plurality of times.

Servo information recorded on the disk is used when the head is positioned on a predetermined track. In a typical disk format, a track is divided into a plurality of sectors, and each sector has a divided data area and a servo area. Track identification information and a burst pattern are recorded as servo information in this servo area. The track identification information is information indicating the track address of each data track, and is read by the magnetic head so that the current track position of the magnetic head can be determined. In the burst pattern, the areas in which signals are recorded are arranged at regular intervals along the radial direction of the disk, and are composed of a plurality of signal recording area rows in which the phases of the signal recording areas are different from each other. The deviation amount of the magnetic head with respect to the data track can be determined based on the signals output from these patterns.

When reading or writing information from or to the magnetic disk, while the magnetic disk is rotating, the head position is checked by the servo information, and when a deviation occurs, the head is driven so as to correct it. Then, position control is executed. Conventionally, in order to always position the head at the center position of the track, the head is positioned on a predetermined track by controlling the PES value obtained from the burst pattern so that it is always a constant value.

FIG. 11 is a diagram schematically showing a conventional track configuration. The left end to the right end in the figure correspond to one round of the disk. The tracks N-1, N, N + 1 are separated from each other by a predetermined distance, and each track is completed as one track, and data is recorded in this track. When the recording of the data is completed on one track, for example, the track N-1, the head moves to the next track N, and after the positioning of the head is completed using the servo data recorded on the track N, the remaining data is recorded. Will continue. In addition,
Each track is typically divided into a plurality of sectors, and servo information is recorded in each sector. Therefore,
The position of the head is controlled on the track by using the servo information for each predetermined interval.

By the way, as described above, when a large amount of data is read or written at a time, in the case of a hard disk having concentric tracks, a data read or write operation and a head to an adjacent track are performed. The seek operation of moving and positioning has to be repeated a large number of times, which requires a long processing time.

That is, in the conventional concentric track structure, a seek operation for each track is indispensable. The time required for the seek operation for one track in the current disk device is about 30% of the time required for one rotation of the disk. Therefore, in the data write operation and the data read operation over several tracks, 30% of the time is spent in the seek operation, resulting in deterioration of performance.

[0008]

SUMMARY OF THE INVENTION In the present invention, data tracks are spirally formed by using servo areas arranged at predetermined intervals in the disk circumferential direction, and the tracks are moved between tracks in reading and writing continuous data. The goal is to improve performance by eliminating the seek operation of.

Still another object of the present invention is to enable spiral track formation by using the conventional embedded servo pattern as it is.

[0010]

According to the structure of the present invention, a PES (obtained by reading a servo area in a recording disk in which tracks are concentrically formed and servo areas are arranged at predetermined intervals along the track is provided. Position
The target of the Error Signal) value is gradually made different for each servo area. That is, conventionally, the head position is controlled based on a constant target PES value so as to always position the head at the track center position. However, in the present invention, the target PES value is gradually changed depending on the sector position of the disk. The head is gradually moved in the radial direction of the disk by using the PES reading value obtained from the servo information area and the target PES value so that the head moves to the conventional adjacent track position by one rotation of the disk. It is a structure to go. Therefore, as in the conventional servo area, the spiral data track can be formed by using the disks arranged along the concentric tracks.

In order to form the spiral track, the value of PES to be read in the servo information area for each sector of the disk is stored in advance in the table. By comparing the PES data recorded in the table with the PES value actually read from the disk by the head,
The positioning of the head is executed.

[0012]

1 shows an example of a disk 18 used in the present invention. The disk 18 has a predetermined thickness dimension, and each surface thereof is a recording surface. The disk 18 is fixed to the spindle and rotates at high speed integrally with the spindle. As shown in FIG. 1, a plurality of position information (servo information) recording areas 50 are radially formed on each recording surface of the disk 18, and a data area 52 is formed in the other area. Has been formed. FIG. 1 is a schematic diagram. In an actual disk, the data areas or servo information areas are formed with a narrower interval, and each disk area is divided into several tens of areas.

FIG. 2 shows a part of the position information recording area 50 and the data area 52. In the data area 52, a plurality of data tracks 54A, 54B, 54C, 54D are concentrically formed at a predetermined pitch. For each data track, reading and writing of data are performed by the magnetic head along the disk circumferential direction (direction of arrow A in FIG. 2).

A track identification information recording area 50A and a burst pattern recording area 50B are provided in the position information recording area. In the track identification recording area 50A, the track address of each data track is recorded in a predetermined code corresponding to each data track 54. A burst pattern is formed in the burst pattern recording area 50B. As shown in FIG. 2, the burst pattern has four burst patterns in which areas where each signal is recorded (hatched portions) are arranged along the radial direction (direction of arrow B in FIG. 2) of the disk 18. Row A ~
D.

The signal recording area 50 of the burst pattern sequence A
The signal recording areas 50b of a and the burst pattern row B are arranged in a staggered pattern along the radial direction of the disk 18. In addition, the sides of both ends of each of the areas 50a and 50b in the radial direction of the disk coincide with the center of the data track 54 in the width direction. The signal recording areas 50c of the burst pattern row C and the signal recording areas 50d of the burst pattern row D are arranged in a staggered pattern along the radial direction of the disk 18. In addition, the edges of both ends of each of the areas 50c and 50d along the disk radial direction coincide with the boundaries between the adjacent data tracks.

Each magnetic head is driven by a circuit as shown in FIG. The signal output of the magnetic head 40 is connected to the input end of an amplifier (AMP) 42, and the signal output from the read element of the magnetic head 40 is amplified by the amplifier (AMP) 42. The output of the amplifier (AMP) 42 is input to a microprocessing unit (MPU) 45 via an analog-digital converter (A / D converter) 44.

The MPU 45 determines the position of the magnetic head based on the signal input from the A / D converter 44, and controls the position of the magnetic head based on the deviation between the determined position of the magnetic head and the target position. Driver 46
To enter. The driver 46 outputs a drive current for the voice coil motor 48 in response to the input signal.

FIG. 4 is a block diagram for explaining the track follow function of the magnetic head realized by the MPU 45. The signal output from the A / D converter 44 is input to the head current position calculation unit 60 and the burst pattern detection unit 62. The burst pattern detector 62 determines whether or not the magnetic head corresponds to the burst pattern recording area based on the input signal, and outputs the result to the current position calculator 60. When the burst pattern detection unit 62 determines that the magnetic head corresponds to the burst pattern recording area, the head current position calculation unit 60 takes in the signal output from the A / D converter 44 and outputs the signal. Based on the above, the present position of the magnetic head along the radial direction of the disk is calculated and output. Therefore, the current head position calculation unit 60 outputs the current head position at predetermined intervals. Note that these configurations are not limited to hardware, and may be realized by software.

The head target position setting unit 64 sets and outputs the target position of the magnetic head represented by the position along the radial direction of the disk. The current head position output from the current head position calculation unit 60 and the target head position setting unit 6
The head target positions output from No. 4 are input to the head position signal generator 66. Head position signal generator 66
Compares the respective signals and outputs a signal y (n) indicating the magnitude and direction of the deviation. The signal y (n) is sent to the main controller 68.
To the driver 4 based on this signal y (n).
6 sends a control signal.

FIG. 5 shows each track N to N + 3 on the disk.
An example of the burst pattern as the PES information recorded in FIG. The burst pattern is, for example, in the cylinder (track) N to N + 3, as shown in FIG.
Four patterns of B, C and D are recorded. A head that passes over these patterns in the track direction (vertical direction in the drawing) reads the signal. The read signal output is
It is the sum of the outputs of the signals of patterns A, B, C, and D shown in FIG. From each of these signals, the head position, that is, the PES value is calculated based on the conditional expression shown in FIG. 5, A, B,
From the comparison of the output values of C and D, the X value, the Y value, and the Z value are calculated using four different sets of equations as shown in FIG. 6, and the resulting value, PES = X / (4 × Y) + Z is used as the PES value. Here, Z is an offset value, which is a constant that differs depending on the above four conditions.

Next, the structure for realizing the spiral track of the present invention by using the servo information will be described in detail. The feature of the servo reading method of the present invention is PES.
Head position control by. Conventionally, in order to hold the head position on a predetermined track, the PES value to be read at each sector position of the track (target PES) is controlled to be kept constant to prevent the head from deviating from the predetermined track. . The PES value can indicate a relative position with respect to a predetermined track by showing, for example, 256 different values in the width direction of one track. In the present invention, the target value of the PES to be read is gradually shifted in each sector.

FIG. 7 is a diagram schematically showing the track structure of the present invention. The area from the left edge to the right edge of the figure corresponds to one disk. 101a, 101b, 101c indicate conventional tracks (cylinders (N-1, N, N + 1)), and 102a, 102b, 102c indicate tracks constructed according to the present invention. The right end of the track 102a coincides with the left end of the track 102b, and both positions indicate the same position. Therefore, the track 102a and the track 102b are formed continuously. The relationship between the track 102b and the track 102c is the same, and in the end, these tracks form one spiral track.

In order to realize such a spiral track by controlling the PES value obtained from the conventional servo information pattern, the target value of the PES value obtained from the servo pattern embedded at a predetermined interval on the track is sequentially changed. To configure. An example will be given of a disk device having 60 servo areas per one round of the disk, that is, a disk device which receives PES information 60 times per one rotation of the disk and thereby executes position control. If there are 256 possible PES values as position information in the width direction of one track, the PES target value is shifted by 256/60 track positions one after another at each of the 60 servo positions. The position of the head is controlled according to the set value. By such position control, the head moves according to the target PES value that differs for each servo area, and follows the spiral track as shown in FIG.

A different target PES value is set for each servo area, and in order to control the head according to this, the correspondence relationship between the servo sector number and the target PES value is held in the system as a table. For example, it is stored in the memory in the head target position setting unit 64 in FIG. An example of this table is shown in FIG. FIG. 8 shows the target PES in each sector when the number of sectors is 60. This is a hexadecimal system and the target PES is a value obtained by shifting the position of 256/60 tracks for each sector. By controlling the head position so that the PES value according to this table is output, the trajectory of the head becomes spiral. The target PES value of the table is sequentially read from the table on the memory every time the head passes through the servo area of the disk. During sequential reading or writing, after the target PES value at the reading or writing start position is read from the table, the PES value incremented by a predetermined value may be sequentially supplied as the target PES value using clock timing.

The table information shown in FIG. 8 is held in the head target position setting unit shown in FIG. This information outputs the target PES value for each sector. The read value of PES and the target PES value are compared, and the position control of the head is executed so as to match the target PES value for each sector recorded in the table. This realizes the spiral data track using the conventional servo pattern.

In order to execute accurate data recording and reading by the spiral track, in the configuration of the present invention, the run-up section at the time of writing start or reading start is set. That is, in order to start writing data at the time when the head is set at the data writing start position on the disk, set several sectors before reaching that position as the run-up section, and write data at the target position, or Enabled to start reading.

In the conventional system, writing or the like can be started by the operation of holding the head on a track on a predetermined concentric circle. However, in the configuration of the present invention, the head does not stay on the predetermined concentric circle. When writing data, etc., a follow-up section is provided to start following a predetermined track, and the head is first moved to a position ahead of the data write start position to start following the track and stabilize. In this state, the reading and writing of data is executed.

FIG. 9 shows the relationship between the run-up section and the data write position. In FIG. 9, the data writing start position is position C. The head position before starting the seek operation for stable running of the head is indicated by A, and the seek completed position is indicated by B. The head at the position A starts the seek operation according to the command to write data from the position C.
This seek operation is performed in order to make the locus of the head substantially coincide with the broken line P in FIG. The seek is completed when the head comes to run stably on the broken line P. In FIG.
The seek operation is shown when there is a data write or read command from the m-th sector (position C) of track N while the head is positioned on track N ′. As shown in the upper part of FIG. 9, the section from the 0th sector to the 0th sector is one round of the disk. In addition, each straight line corresponding to the tracks N-1, N, N + 1 indicates the center position of each track.

FIG. 10 shows a flow for setting a target PES necessary for controlling head running on the dashed line P which is the approach section shown in FIG. The number of sectors per disk lap is M
(0, 1, 2 ... M-1), the data writing or reading start position is the mth sector of track N, and the range of PES values per track is 256 (PES / TR).
K), that is, 256 positions can be identified by 256 PES values per track. Further, the distance that the head moves in the disk radial direction per sector when writing or reading sequential data is T = 256 / M (PES / Sector). At this time, the target PES in sector x (0 ≦ x ≦ M−1) is obtained according to the flow shown in FIG.

A flow similar to that shown in FIG. 10 determines the PES value for traveling on the broken line P, which is the run-up section shown in FIG. 9, when the head is located in the sector x. As a result of this flow, by sequentially supplying the obtained PES value as the target PES to the head target position setting unit in FIG. 4, the locus of the head is brought closer to the broken line P shown in FIG. The seek operation ends when the head stably starts traveling on the broken line P, that is, at the position B in FIG. After this, the head also runs along the broken line P. After the seek operation is completed, the head starts writing or reading data on the Nth track and the mth sector (position C).
At that point, writing or reading of data is started. The position control of the head is executed from this position using the table shown in FIG. 8, and as a result, writing or reading of data is executed in the shaded area Q shown in FIG.

After that, the position control of the head is executed based on the PES value given by the table shown in FIG.
Data is written to or read from the data track on the spiral.

[0032]

As described above, according to the configuration of the present invention, by using the servo area formed for the concentric tracks,
It is possible to form a spiral data track. Therefore, a seek operation for moving between tracks at the time of writing or reading data becomes unnecessary, and the performance can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a data area and a servo area of a disk in a disk device according to the present invention.

FIG. 2 is a diagram showing track position identification information on a disk according to the present invention.

FIG. 3 is a block diagram showing a block configuration of a head position control in the disk device according to the present invention.

FIG. 4 is a block diagram showing the internal configuration of the MPU in the configuration relating to the position control of the head in the disk device according to the present invention in blocks.

FIG. 5 is a diagram showing a relationship among tracks, position identification information, and tracks on a disc according to the present invention.

6 is a diagram showing a flow for obtaining a head position from the position identification information shown in FIG.

FIG. 7 is a diagram showing a spiral track of a disk according to the present invention.

FIG. 8 is a view showing a table used for forming a spiral track in the disk device according to the present invention.

FIG. 9 is a diagram illustrating a data reading / writing start point and an approach section according to the present invention.

FIG. 10 is a flow chart used for supplying a PES value for the head to travel in an approach zone according to the present invention.

FIG. 11 is a view showing a conventional concentric track.

[Explanation of symbols]

40 magnetic head 42 AMP 44 A / D converter 45 MPU 50 position information recording area 50A identification information recording area 50B burst pattern recording area 52 data area 60 head current position calculation unit 62 burst pattern detection unit 64 head target position setting unit 102 spiral Track 201 Track trajectory in run-up area 202 Track trajectory in data reading / writing area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Ogasawara, No. 1 Kirihara-cho, Fujisawa-shi, Kanagawa Japan IBM Corporation Fujisawa Plant (72) Inventor, Yoshimi Masuda Kirihara-cho, Fujisawa-shi, Kanagawa Japan IBM Corporation Fujisawa Plant (72) Inventor Takashi Nakamura 1 Kirihara Town, Fujisawa City, Kanagawa Prefecture Japan IBM Corporation Fujisawa Plant (72) Inventor Hiroshi Yanagisawa 1 Kirihara Town, Fujisawa City, Kanagawa Prefecture Address Japan BM Co., Ltd. Fujisawa Office

Claims (8)

[Claims] 1. A disk device for rotating a recording disk and reading and / or recording a signal recorded on a track on the disk by a head that floats on the disk. ,
Position information for positioning the head is recorded on the disk, and the disk has a head position control means for driving the head substantially in the radial direction of the disk and holding it at a predetermined position on the disk. In the apparatus, the position information is recorded in a plurality of servo areas existing on the circumference of a concentric circle of the disk, and a PES (position error signal) indicating the position is output to the servo areas by being read by the head. And a table for recording the correspondence between each of the plurality of servo areas and the target PES value, and means for executing control of the head based on the target PES value supplied by the table. A disk device comprising: 2. The pattern comprises a plurality of burst pattern rows in which signal recording areas are arrayed at regular intervals in the radial direction of the disk and the phases of the signal recording areas are different from each other. The disk device according to claim 1. 3. The disk device according to claim 1, wherein the servo area is formed for each sector formed at predetermined intervals in the track. 4. The disk device according to claim 3, wherein the target PES value linearly changes according to a sector position. 5. The disk device according to claim 1, wherein the disk is a magnetic disk, and the head is a magnetic head. 6. A disk device for rotating a recording disk and reading and / or recording a signal recorded on a track on the disk by a head that floats on the disk. ,
Position information for positioning the head is recorded on the disk, and the disk has a head position control means for driving the head substantially in the radial direction of the disk and holding it at a predetermined position on the disk. A head position control method in an apparatus, wherein a track width direction on a disk recorded for each servo area corresponding to each of a plurality of sectors existing on a line along a circumferential direction of a concentric circle of the disk in the position information The position of the head is determined from the table in which the correspondence between the step of obtaining the output of the PES indicating the head position by reading the position-identifiable pattern and the target PES value that changes linearly with the sector position of the disk is recorded. Reading the target PES value at the sector position, and the target PE read from the table above A step of inputting a value as a head control target position into the head position control means, and executing the head position control with a target PES value that differs depending on the sector position, thereby running the head in a spiral shape and A head position control method for a disk device, which comprises forming a track. 7. The pattern comprises a plurality of burst pattern rows in which signal recording areas are arranged at regular intervals along the disk radial direction and the phases of the signal recording areas are different from each other. 7. A head position control method for a disk device according to claim 6. 8. The writing or reading of data is started after the head is run as a run-up section on a line including a spiral data track at a sector position preceding the sector position for starting reading or writing of data. A head position control method for a disk device according to claim 6 or 7.