JPH08335376A - Data recording/reproducing device and controlling method for positioning of its head - Google Patents

Abstract

PURPOSE: To attain reliable data reproduction in a data recording/reproducing device which uses a head of combined head structure having a MR head by controlling the positioning of the head for read action at the readout position of exact data at the time of reproduction. CONSTITUTION: At the time of data reproduction, the CPU 12 control the positioning of an MR head 10 on the center of the target track based on the burst data on a disk 2. This time, using the data for offset adjustment reproduced by the MR head 10, offset adjustment for position determination on the center of the actual data area is conducted. By this, exact positioning on the center of the data area on which data is recorded by a thin-film head 11 is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk apparatus, and more particularly to a data recording / reproducing apparatus having a function of controlling positioning of a head at a track center based on servo data prerecorded on a disk.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk device such as a hard disk device (HDD) uses a disk as a recording medium, and a head records data on the disk and reproduces data from the disk.

In a small HDD, the head is held by a rotary type actuator (carriage), and the rotary drive of the actuator moves the head in the radial direction of the disk. The actuator is driven by a voice coil motor (VCM).

The HDD is provided with a head positioning control system for driving and controlling the VCM and moving the head to a target track (target cylinder) on the disk for positioning control. The head positioning control system is roughly divided into a servo data reproducing system and a microprocessor (CPU) that executes positioning control.

The servo data is recorded in the servo area provided on each track on the disk. The servo areas are arranged at the same position on each track with a predetermined interval in the circumferential direction. A data sector, which is one or a plurality of data areas, is arranged between the servo areas.

Servo data is roughly classified into a cylinder code (track address) used for seek control and burst data used for position control. The CPU executes seek control to move the head to the target track (track including the sector to be accessed). After this, position control (also called track following control) is performed to position the head at the center of the target track.

By the way, in recent years, in HDDs, as read-only heads, MR (magnetoresistiv) is used.
e) The head is receiving attention. Since the MR head is read-only, it usually forms a composite head structure using a thin film head as a write head. Hereinafter, the head having this composite head structure is simply referred to as a head.

As shown in FIG. 6A, the head 1 is provided at the tip of the slider 1a, and moves in the radial direction of the disk 2 by driving the actuator.
The head 1 includes an MR head 10 as shown in FIG.
And the center of the gap of the thin film head 11 are located substantially on the same line. Therefore, the azimuth angle y exists between the MR head 10 and the thin film head 11 with respect to the track center.

When recording data, as shown in FIG. 6A, the thin film head 11 is positioned at the center of the track, and the width of the data area corresponding to the gap width (that is, the data track width) 2a is set. Execute the data write operation. At this time, because of the azimuth angle y,
A position shift (offset) occurs with respect to the width 2b of the data area read by the MR head 10.

At the time of reproducing data, the MR head 10 reproduces burst data of servo data recorded in the servo area of the track, and positioning control is performed at the track center based on the burst data, and a read operation for reading the recorded data. To execute. At this time, since the data writing position of the thin film head 11 and the reading position of the MR head 10 are misaligned, a normal read operation may not be possible.

[0011]

In a conventional HDD, in which a read-only MR head is used, the read position of the MR head and the position of the recorded data deviate from each other. It is necessary to adjust the offset to reach the target position (center position of the target track). However, since the conventional burst data has a positional deviation from the position of the recording data written by the thin film head 11, accurate offset adjustment cannot be performed only by using the burst data.

An object of the present invention is to ensure the reliability of data recording / reproducing apparatus using a head having a composite head structure having an MR head, by controlling the head for read operation at an accurate data read position during data reproduction. It is to realize data reproduction.

[0013]

The present invention relates to a data recording / reproducing apparatus such as a magnetic disk apparatus having a servo function for positioning and controlling a head at a target position based on servo data previously recorded on a disk. Data writing means for recording offset adjustment data at the beginning of each data area on the disk during data writing operations such as formatting, and offset of the head with respect to the target position by using the offset adjustment data during head positioning control Is a device provided with a control means for adjusting.

[0014]

According to the present invention, the data writing means records the offset adjusting data at the head portion of each data area when the data writing operation such as formatting is performed. The offset adjusting data is a kind of burst data for adjusting the offset when the head is positioned at the center of the target track which is the target position.

The control means controls the positioning of the head at the center of the target track on the basis of the burst data of the servo data, especially when reproducing the data. At this time, the offset adjustment data reproduced by the head is used to perform the offset adjustment for positioning the head at the center of the original data area. As a result, when a read-only head such as an MR head is used and different heads are used when writing and reading data, when the data after the write operation is reproduced, positioning control of the read-only head is performed. It is possible to eliminate the offset and reliably position the data in the center of the data area.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram for explaining the format of a disk used in the HDD according to this embodiment.
FIG. 3 is a block diagram showing a main part of the HDD according to this embodiment. (Structure of HDD) As shown in FIG. 2, the HDD of this embodiment uses a head 1 having a composite head structure in which an MR head 10 as a read-only head and a thin film head 11 as a write operation head are integrated. System magnetic disk device.

The heads 1 are provided on both sides of the disk 2 and are held by the head actuator 4. The head actuator 4 is rotationally driven by a voice coil motor (VCM) 5 to move the head 1 in the radial direction of the disk 2. VCM5 is CPU
A drive current is supplied from the VCM driver 6 controlled by 12.

The disk 2 is provided with one disk or a plurality of disks (one disk is used for convenience in this embodiment), and is rotated at a high speed by the spindle motor 3. The disk 2 has a format in which a large number of tracks are arranged as described later, and each track has a format having a servo area and a data area (see FIG. 1).

The read / write circuit 7 is usually composed of a dedicated integrated circuit and executes data read / write processing. The read / write circuit 7 converts write data WD output from a disk controller (HDC) (not shown) into a write current, and a thin film head 11 for write operation.
Output to. The read signal output from the read-only MR head 10 is converted into digital read data RD.

The HDD has a servo system circuit for controlling the positioning of the head 1 on a target track (a track including a data area to be accessed) on the disk 2.
Servo system circuits are roughly classified into a servo controller 13, a full-wave rectifier circuit 8, a peak hold circuit 9, and a CPU 1.
It consists of two. The servo controller 13 extracts a cylinder code (track address) from the read signal reproduced by the read / write circuit 7 and determines a sample signal S for determining the sample timing of the peak hold circuit 9.
A to SE are generated and output.

The cylinder code is seek control data included in servo data recorded in a servo area on the disk 2 described later. The servo data includes burst data for position control. The CPU 12 executes seek control (speed control) for moving the head 1 to the target track based on the cylinder code.

Full-wave rectifier circuit 8 and peak hold circuit 9
Is a circuit for detecting and holding the peak value of burst data from the read signal output from the read / write circuit 7. The peak hold circuit 9 of this embodiment is
In addition to the burst data (A to D) of the normal servo area, the peak value of the offset adjustment data (burst data E) recorded in the data area is held.

The CPU 12 converts each peak value held in the peak hold circuit 9 into digital data by the A / D conversion circuit 12a and inputs it, and performs position control (track follow-up control) and offset adjustment related to this embodiment. To execute.

The CPU 12 is a control microprocessor (microcontroller) for executing various control processes such as servo control, and is a main constituent element of the servo system circuit. As will be described later, the CPU 12 executes offset adjustment during position control of the MR head 10 related to this embodiment. (Explanation of Disc Format) Disc 2 of this embodiment
Has a large number of tracks arranged concentrically. As shown in FIG. 1A, the format of each track is roughly divided into a servo area 20 and a data area 21.

The servo areas 20 are arranged at the same position on each track and at a predetermined interval in the circumferential direction. In the servo area 20, as described above, the servo data composed of the cylinder code 22 and the burst data 23 is roughly recorded. The servo data is usually written by a dedicated servo writer when manufacturing the HDD.

The data area 21 is a sector divided as an access unit, and has a user data section 24, an ID data section 25, synchronization signal (SYNC) sections 26a, 26b and the like. One or more data areas 21 are provided between the servo areas 20.

The user data section 24 is an area for recording data read / written by the head 1. I
Identification information (ID data) necessary for accessing each sector is recorded in the D data section 25. SYN
A signal for generating a synchronization signal (PLL signal) at the time of reproducing each data is recorded in the C portions 26a and 26b, which are arranged at the head portions of the user data portion 24 and the ID data portion 25, respectively. ing.

In the present embodiment, the offset adjustment data E is recorded at the head of the data area 21, for example immediately before the SYNC portion 26a of the ID data portion 25. The offset adjustment data E is burst data having the same frequency as the burst data A to D recorded in the servo area 20.

In this embodiment, the offset adjustment data E
Is controlled by the CPU 12 during formatting of the HDD and the ID data section 25 and the synchronization signal sections 26a and 26b.
At the same time, the data is written in the data area 21 by the thin film head 11. (Head Positioning Control) Next, the head positioning control operation of this embodiment will be described with reference to FIGS.

In the present embodiment, the formatting is executed, and as shown in FIG. 1A, the ID data section 25 and the sync signal section 2 are provided in each data area 21 of each track N.
It is assumed that the offset adjustment data E is also recorded together with 6a and 26b. Further, during the data writing operation, the thin film head 11 writes user data in the user data portion 24 of the data area 21. It is assumed that the MR head 10 is positioned and controlled to the target track N including the data area 21 during the data read operation for reproducing the data of the user data section 24.

First, as shown in step S1 of FIG.
The CPU 12 executes seek control based on the cylinder code reproduced from the servo area 20, and moves the head 1 to the target track N. Here, since the data read operation is being performed, the MR head 1 which is actually integrated is used.
Move 0 to target track N.

When moved to the target track N, the CPU
12 shifts from seek control to position control. In the position control, as shown in FIG. 1B, each peak value of the burst data A to D recorded in the servo area 20 of the target track N is sampled and held (step S2). CP
U12 executes position control (track follow-up control) for correcting the position error so as to position the MR head 10 at the center of the target track N.

That is, the MR head 10 uses the target track N
The burst data A to D are read from the servo area 20 and output to the read / write circuit 7. The peak hold circuit 9, as shown in FIG.
At each timing, the peak values of the burst data A to D output via the read / write circuit 7 and the full-wave rectifier circuit 8 are sampled and held. Servo controller 13
Are sample signals SA to during the output period of the servo gate SG.
Output SD. The full-wave rectifier circuit 8 full-wave rectifies the read signals corresponding to the burst data A to D and outputs the read signals to the peak hold circuit 9, as shown in FIG.

The CPU 12 converts each peak value held in the peak hold circuit 9 into digital data by the A / D conversion circuit 12a and inputs the digital data, and executes the control processing required for position control (steps S3 and S4). . CPU1
2 calculates the position error amounts “(A−B) / (A + B)” and “(C−D) / (C + D)” based on the input digital data of the burst data A to D. Based on this position error amount, the VCM driver 6 outputs a control amount according to the position error of the MR head 10 with respect to the track center.
The VCM 5 is driven and controlled via the to position the MR head 10 at the track center (see FIG. 1B). (Offset adjustment processing) In this embodiment, the servo area 2
The peak hold circuit 9 holds the peak value of the offset adjusting data E read by the MR head 10 together with the sampling of the burst data A to D from 0 (see FIG. 3). The offset adjustment data E, which is burst data having the same frequency as the burst data A to D, is recorded in the data area 21.

The CPU 12 sets the peak value of the offset adjusting data E to A as in the case of inputting the burst data A to D.
The data is converted into digital data by the / D conversion circuit 12a and input (step S6). The CPU 12 uses the input offset adjustment data E to execute the offset adjustment processing of the MR head 10 (step S9).

That is, the CPU 12 causes the burst data A to
After the MR head 10 is positioned substantially at the track center by the position control using D, the peak values of the offset adjustment data E and the burst data D are compared (step S7). Here, as shown in FIG. 1B, the target track is an adjacent track (N + 1 or N−) of the track N.
In the case of 1), burst data C is used instead of burst data D.

The CPU 12 receives the input burst data D
The peak position of the MR head 10 is offset-adjusted until the peak value of the offset adjustment data E matches the burst data D with reference to the peak value of (No in step S8).
O, S9).

By such offset adjustment, as shown in FIG.
As shown in (B), when the actual data area 21a is displaced from the track center by the offset amount y with respect to the data area 21 corresponding to the original track center, the data area 21a is moved to the center of the data area 21a. MR head 10
a can be positioned. Therefore, the MR head 10a uses the thin film head 11 for the data area 21a.
The user data written in can be accurately read.

That is, as described above, the head 1 having the composite head structure has a writing position and a reading position due to the positional relationship (existence of azimuth angle) between the read-only MR head 10 and the write thin-film head 11. An offset y occurs between the two. The thin film head 11 uses the burst data A to D reproduced by the MR head 10 to track N
Positioning is controlled at the center of. At this time, as shown in FIG. 1B, the thin film head 11 is positioned with a displacement of y from the original track center (position of the MR head 10).

In the present embodiment, when the thin film head 11 is writing data (formatting), the offset adjusting data E is recorded at the beginning of the data area 21a. By using the offset adjustment data E, the MR head 10 is offset-adjusted when the data is reproduced by the MR head 10, and the actually recorded data area 21 is recorded.
It can be positioned at the center of a (the position of the MR head 10a). (Modification) In the present embodiment, offset adjustment data E which is burst data recorded in the data area 21 is used for offset adjustment of the MR head 10. On the other hand, in the modified example, for example, the SYCN signal portion 26a at the head of the data area is used as offset adjustment data.

The SYCN signal portion 26a is also called a PLL sync field, and is usually an area for generating a synchronization signal (synchronization clock pulse) when reproducing ID data. The CPU 12 A / D-converts and inputs the peak value F of the SYCN signal unit 26a sample-held at the timing of the sample signal SE by the peak-hold circuit 9 (see FIG. 5).

The peak value F is used as the offset adjustment data of the MR head 10 in the same manner as the peak value of the offset adjustment data E. That is, the CPU 12
After positioning the MR head 10 at the track center based on the burst data A to D, the MR head 10 is offset-adjusted to the position where the peak value F becomes the maximum value. As a result, the MR head 10 can be positioned and controlled at the center of the data area 21 actually recorded by the thin film head 11.

Note that S used for offset adjustment is used.
The YCN signal part does not have to be recorded at the beginning of the ID data part 25. For example, in the case of a disc format without the ID data section 25, the SYCN signal section 26b recorded at the beginning of the user data section of the data area may be used.

[0044]

As described above in detail, according to the present invention, the offset adjustment data recorded in the data area on the disk is used to perform the offset adjustment of the head positioned at the target position based on the servo data. be able to. Therefore, since the head can be accurately positioned at the target position in the actual data area, the data reproducing operation by the read head can be accurately executed. In particular, if it is applied to a magnetic disk device that uses a head having a composite head structure that uses an MR head only for reading, it is possible to position and control the MR head at an accurate data read position.

[Brief description of drawings]

FIG. 1 is a conceptual diagram for explaining a format of a disk used in an HDD according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main part of an HDD according to this embodiment.

FIG. 3 is a timing chart for explaining the operation of this embodiment.

FIG. 4 is a flowchart for explaining the operation of this embodiment.

FIG. 5 is a timing chart for explaining a modified example of the present embodiment.

FIG. 6 is a conceptual diagram for explaining the operation of a conventional HDD having a composite head structure.

[Explanation of symbols]

1 ... Head, 2 ... Disk, 3 ... Spindle motor, 4
… Head actuator, 5… Voice coil motor (V
CM), 6 ... VCM driver, 7 ... Read / write circuit, 8 ... Full-wave rectifier circuit, 9 ... Peak hold circuit, 10
... MR head, 11 ... Thin film head, 12 ... Microprocessor (CPU), 13 ... Servo controller.

Claims (5)

[Claims] 1. A head means for reading / writing data, a servo area in which servo data for positioning and controlling the head means at a target position are recorded, and data read / written by the head means are recorded. A data area for storing offset adjustment data in the range of the data area by using the head means, and positioning the head means at the target position based on the servo data. A data recording / reproducing apparatus comprising: a control unit that adjusts an offset of the head unit with respect to the target position by using the offset adjustment data reproduced by the head unit when controlling. 2. A head means for reading / writing data and a plurality of servo areas are provided in each track at predetermined intervals, and each servo area is for positioning the head means at the center of the track. Burst data is recorded, and a disk provided with a plurality of data areas for recording data read / written by the head means between the servo areas, and a data writing operation by the head means, Data writing means for writing offset adjustment data having the same frequency as the burst data at the head of each data area, and the head for positioning the head means at the center of a target track based on the burst data. Ratio of the offset adjustment data and the burst data reproduced by the means A data recording / reproducing apparatus comprising: a control unit that adjusts an offset of the head unit with respect to a center of the target track based on a comparison result. 3. A head means for reading / writing data and a plurality of servo areas are provided in each track at predetermined intervals, and each head is positioned at the center of the track in each servo area. A data recording / reproducing apparatus having a disk in which burst data is recorded and a plurality of data areas for recording data read / written by the head means are provided between the servo areas. During the data write operation to the data area, recording offset adjustment data having the same frequency as the burst data at the head of each data area, moving the head means to a target track, and based on the burst data A step for positioning the head means at the center of the target track. A step of reproducing the offset adjusting data by the head means, and adjusting an offset of the head means with respect to the center of the target track based on a comparison result of the offset adjusting data and the burst data. A head positioning control method comprising: 4. A head means for reading / writing data, a servo area in which servo data for controlling positioning of the head means at a target position is recorded, and data read / written by the head means are recorded. And a disk having a data area provided with a synchronous area for generating a synchronous clock when reproducing the data, and when performing positioning control of the head means at the target position based on the servo data, A data recording / reproducing apparatus comprising: a control unit that adjusts an offset of the head unit with respect to the target position based on a level value of a synchronization signal reproduced by the head unit from the synchronization area. 5. A head means for reading / writing data and a plurality of servo areas are provided at predetermined intervals on each track, and each servo area is for positioning the head means at the center of the track. Burst data is recorded, and a disk provided with a plurality of data areas for recording data read / written by the head means between the servo areas, and a data writing operation by the head means, Data writing means for recording offset adjustment data having the same frequency as the burst data at the head of each data area, position error data is generated from the burst data, and the head means is targeted based on the position error data. Position control is performed to position the track at the center of the track, and The burst data for determining the position adjustment direction when positioning the head means at the center of the target track is compared with the offset adjustment data, and the head with respect to the center of the target track is matched so that the comparison results match. And a control means for adjusting the offset of the means.