JPH06349215A - Positioning controller for head of magnetic recorder/ reproducer - Google Patents

Abstract

PURPOSE:To obtain a head positioning controller capable of realizing positive read/write operation by reducing the quantity of a track displaced in a head at the time of read/write without diminishing read gap width so much. CONSTITUTION:In a magnetic recorder/reproducer using a head having combined head structure, a servo circuit 19 positions and controls the gap for reading data or gap for writing data of the head 10 at the center of a target track on the basis of servo information recorded on a disc 14. Correction processing only by the quantity of the track displaced between each gap is conducted on the basis of positional correction data stored in a ROM 22 at the time of the positioning control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head positioning control device for performing head positioning control based on servo information prerecorded on a disk in a magnetic recording / reproducing device such as a hard disk device.

[0002]

2. Description of the Related Art Conventionally, for example, a hard disk drive (HD
The magnetic recording / reproducing apparatus such as D) is provided with a head for recording / reproducing data on / from a disk which is a recording medium. The head is an inductive type head such as a thin film head and an MR (m
It is roughly classified into magnetic flux response type heads such as an aggregate resistive head.

In recent years, particularly in HDDs, the recording density has dramatically increased, and the reproduced signal per bit becomes weak, so that a highly sensitive head is required. The MR head is a head that detects the magnetic field generated on the surface of the disk as a change in resistance value by utilizing the anisotropic magnetoresistive effect. M
The R head has a high sensitivity with respect to an induction type thin film head and the like, and has an advantage that the magnitude of the reproduction signal does not depend on the running speed of the disk. Therefore, a high recording density HDD using an MR head as a head has been developed.

However, the MR head is a read-only head. Therefore, a magnetic recording / reproducing apparatus such as an HDD requires a write-only head in addition to the MR head. Specifically, an inductive thin film head is used as a write-only head, and a head having a composite head structure including this thin film head and an MR head is used. As shown in FIG. 6A, the head of the composite head structure has M
It consists of an R head 1 and a thin film head 2 dedicated to writing. The thin film head 2 has an upper magnetic pole 3, a lower magnetic pole 4, a coil 5 and a write gap 6. The thin film head 2 writes data on the disk by the recording magnetic field generated from the write gap 6.

In such a head, as shown in FIG. 6B, the thickness of the shield of the MR head 1 and the thickness of the magnetic pole of the thin film head 2 are between the read gap and the write gap 6 of the MR head 1. Therefore, there is a distance d of several μm to several tens of μm. Here, a wide write / narrow read system is generally used in which the read gap width T2 is smaller than the gap width T1 of the write gap 6.

On the other hand, in the HDD, a rotary type actuator is used as a head moving mechanism (carriage mechanism). In such a head moving mechanism, as shown in FIG.
As shown in (A), the head gap (MR head 1
The read gap and the write gap 6) have an azimuth angle φ depending on the track position of the disc (radial direction of the disc). The azimuth angle φ is an angle between the disc traveling direction Y and the head gap normal line X. Since this azimuth angle φ is generated, the read track TR1 from which data is read by the read gap of the MR head 1.
Between the track TR2 and the track TR2 where the data is written by the write gap 6 and the track gap TE (TE = d · s).
in φ) occurs.

When such a track shift amount TE occurs, a situation may occur in which data is erroneously read from an adjacent track when data is read from the disk, or erroneously written to an adjacent track when data is written. Occurs, which causes an error. Therefore, conventionally, the wide write / narrow read method as described above is adopted, and
As shown in (B), the gap width T of the write gap 6
1, the read head gap width T2 of the MR head 1 is relatively small. That is, the following formula (1)
If the above condition is satisfied, the read track TR1 comes to exist within the range of the write track TR2. TE = d · sin φ ≦ (T1−T2) · cos φ / 2 (1) where d is the gap distance, T1 is the write gap width, T2 is the read gap width, and φ is the azimuth angle.

[0008]

Conventionally, since a data read / write error due to an azimuth angle φ is likely to occur in a composite head structure using an MR head, a wide read gap width of the MR head is relatively small. The write / narrow read method is used.

However, the reduction of the read gap width of the MR head and the reduction of the track width are limited in terms of the track density (TPI) of the disk and the reproduction signal level at the time of reading. Specifically, for example, 2.5
In the case of an inch HDD, the azimuth angle φ is about 15 degrees at maximum, and assuming that the gap distance d is 10 μm, (T1−T2) ≧ 5.2 μm. Therefore,
When the track density (TPI) is increased, it is necessary to reduce the read gap width of the MR head considerably. For example, assuming that the write gap width T1 is 6 μm,
There is no solution if the read gap width T2 needs to be 0.8 μm or less, and if the write gap width T1 is 5 μm or less. Also, if the read gap width is made smaller, the reproduction signal level at the time of read becomes smaller, and the HD
There is a problem that the S / N ratio of D and the error rate are lowered.

An object of the present invention is to ensure a reliable magnetic recording / reproducing apparatus using a head having a composite head structure, by reducing the track deviation of the head during read / write without making the read gap width so small. It is an object of the present invention to provide a head positioning control device capable of realizing read / write operations.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a composite head structure having a data read gap and a data write gap, such as an MR head, and head means for recording / reproducing data on / from a disk, and a data read gap. Memory means for storing position correction data determined in advance according to the amount of track position deviation occurring between the data writing gaps, and the data reading gap or the data writing gap based on the position correction data stored in the memory means is the target track. The head positioning control device is provided with a head positioning control unit that performs a positioning control correction process so as to position the center of the head.

[0012]

According to the present invention, the head positioning control means positions the data reading gap of the head at the center of the target track based on the servo information recorded on the disk when performing the data reading operation, for example. On the other hand, when the data write operation is performed, the data write gap of the head is positioned at the center of the target track based on the servo information. At the time of this positioning control, the correction processing of the positioning control is performed based on the position correction data stored in the memory means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the main part of a head positioning control device for a hard disk drive (HDD) according to the first embodiment, FIG. 2 is a flow chart for explaining the operation of the same embodiment, and FIG. 3 (A) is the same. FIG. 3B is a conceptual diagram for explaining the operation of the embodiment, FIG. 3B is a conceptual diagram for explaining the configuration of the disk according to the second embodiment, and FIG. 4 is a diagram for explaining the operation of the second embodiment. It is a flowchart of.

As shown in FIG. 1, the HDD is a disk rotating mechanism for rotating and driving a disk 14 as a recording medium, a servo mechanism for positioning the head 10 on a target track on the disk 14, and recording / reproducing of data. It has a read / write circuit 15 for performing. The disk rotation mechanism has a spindle motor 16 and a spindle motor (SPM) driver 17 that rotate and drive the disk 14. The SPM driver 17 drives the spindle motor 16 according to a motor control signal from a disk controller (HDC) 18.

The head 10 is a head having a composite head structure composed of an MR head 1 having a read gap dedicated to a read operation and a thin film head having a write gap 6 dedicated to a write operation (see FIG. 6). Between the read gap and the write gap 6 of the MR head 1 is several μm to several tens of μm.
There is a distance d between the gaps. Further, the read gap width T2 is formed relatively smaller than the gap width T1 of the write gap 6.

The servo mechanism includes an actuator (carriage mechanism) 11 for holding the head 10 and the actuator 1.
Voice coil motor (VCM) 1 for driving 1
2. It has a VCM driver 13 and a servo circuit 19 for driving the VCM 12. Servo circuit 19 is VCM
The driver 13 is controlled to execute servo processing for positioning the head 10 on a target track on the disk 14.

The servo circuit 19 executes the servo processing and outputs a positioning control signal to the VCM driver 13 CP.
A U20, a position information generation circuit 21 for generating position information from the read data R output from the read / write circuit 15, and a ROM (read only memory) 22 storing position correction data according to the gist of the present invention. R
The OM22 is used for each track or CDR (constan
In the case of the t density recording method, position correction data for each zone is stored. The position correction data is generated by the azimuth angle φ of the head 10, and the track deviation amount T generated between the read track TR1 for reading data by the read gap of the MR head 1 and the write track TR2 for writing data by the write gap 6.
It is offset data for correcting E (TE = d · sin φ).

The read / write circuit 15 includes a disk 14
Is a circuit for generating a write current according to the write data for writing to, and reproducing the read data R from the read signal from the head 10. The write gap 6 of the head 10 generates a recording magnetic field corresponding to write data by the write current from the read / write circuit 15.

The read / write circuit 15 reproduces the servo information previously recorded on the disk 14 by the read gap of the head 10 and outputs it as read data R to the servo circuit 19. In this embodiment, the sector servo system is assumed, and the servo information is roughly divided into track (cylinder) address information and servo burst data for positioning. The read / write circuit 15 outputs servo burst data to the position information generation circuit 21 during position control for positioning the head 10 at the center of the target track. The position information generation circuit 21 generates position information (position error data) and outputs it to the CPU 20.

Next, the operation of the first embodiment will be described. H
In the DD, when there is an access from the HDC 18, the servo circuit 19 moves the head 10 to a target track on the disk 14 and starts a seek operation for positioning at the center of the target track (step S1 in FIG. 2). . During the seek operation, the read gap of the head 10 causes the servo information previously recorded on the disk 14 to be read,
It is output to the read / write circuit 15.

The read / write circuit 15 outputs read data R corresponding to the servo burst data of the reproduced servo information to the position information generation circuit 21. CPU 20
Based on the position information generated by the position information generation circuit 21, the VCM 12 is driven and controlled via the VCM driver 13 so as to control the positioning of the head 10 at the center of the target track (step S2).

Here, during the data write operation, the CP
The U20 reads the position correction data from the ROM 22 and executes the position correction process so as to position the write gap 6 of the head 10 at the center of the target track (step S).
3 YES, S4, S5). That is, as shown in FIG. 3A, a track deviation amount TE (TE = d · sin φ) is provided between the read gap and the write gap 6 of the MR head 1 due to the azimuth angle φ and the gap distance d. Existing.

Therefore, during the data write operation,
The CPU 20 sets the target position of the read gap of the MR head 1 to the track deviation amount T based on the position correction data for each track (or each zone) stored in advance in the ROM 22.
A process of correcting the position by E is performed (step S4).
As a result, as shown in FIG. 3A, the write gap 6 can be positioned at the center (Y) of the write track TR2 that is the target track during the data write operation (step S5). The write gap 6 is read /
A write magnetic field is generated by the write current from the write circuit 15 to write data in the write track TR2 (step S6).

On the other hand, during a data read operation, the CPU
The position control unit 20 positions the read gap of the MR head 1 at the center of the target track based on the position information generated by the position information generation circuit 21 (N in step S3).
O, S7). That is, the CPU 20 positions the read gap of the MR head 1 at the center of the write track TR2 based on the servo information recorded on the write track TR2. Therefore, as shown in FIG. 3A, the read gap of the MR head 1 can be positioned at the center (Y) of the read track TR1 which is the target track during the data read operation (step S7). The read track TR1 has a gap width T1 of the write gap 6.
By the relative size of the read gap width T2 with respect to
It is included in the range of the write track TR2.
The read gap of the MR head 1 is the read track TR.
The magnetic field from 1 is extracted and a read current is output to the read / write circuit 15 (step S8).

In this way, based on the position correction data stored in the ROM 22 in advance, at the time of data writing operation, the write gap 6 of the head 10 is positioned at the center of the target track by the track shift amount TE. Correct the position. Therefore, the write gap 6 of the head 10 can be positioned at the center of the target track by correcting the position error corresponding to the track shift amount TE existing between the read gap of the MR head 1. Further, in the embodiment, when the read gap of the MR head 1 is positioned at the center of the target track during the data read operation, the position correction is executed by the track shift amount TE based on the position correction data. Good. In this case, as a matter of course, during the data writing operation, the write gap 6 of the head 10 is position-controlled to the target position based on the servo information, and the position correction is not executed.

FIGS. 3B and 4 are diagrams relating to the second embodiment of the present invention. In the second embodiment, the disk 1
As shown in FIG. 3B, the servo information prerecorded in 4 includes write burst data WB and read burst data RB as servo burst data. The write burst data WB and the read burst data RB are deviated in recording position by the track deviation amount TE. The servo burst data is used when the servo circuit 19 positions the head 10 at the center of the target track as described above.

In the embodiment, during the write operation, the servo circuit 19 positions the write gap 6 of the head 10 at the center of the target track based on the write burst data WB. On the other hand, during the read operation, the servo circuit 19
Positions the read gap of the MR head 1 at the center of the target track based on the read burst data RB.

That is, as shown in step S10 of FIG. 4, when the seek operation is started, the servo circuit 19 moves the head 10 to a target track on the disk 14,
Positioning control is performed to position the track at the center of the target track. During this positioning control, the servo burst data of the servo information previously recorded on the disk 14 is read by the read gap of the head 10.

During the data write operation, the servo circuit 1
Reference numeral 9 drives and controls the VCM 12 to position the write gap 6 of the head 10 at the center of the target track based on the write burst data WB read by the read gap of the MR head 1 (YES and S in step S11).
12, S13). As a result, as shown in FIG. 3A, the write gap 6 can be positioned at the center (Y) of the write track TR2 that is the target track during the data write operation. The write gap 6 generates a recording magnetic field by the write current from the read / write circuit 15 to write data in the write track TR2 (step S14).

On the other hand, during the data read operation, the servo circuit 19 determines the VCM1 based on the read burst data RB read by the read gap of the MR head 1.
2 is controlled to position the read gap of the MR head 1 at the center of the target track (N in step S11).
O, S15, S16). As a result, as shown in FIG. 3A, during the data read operation, the read gap of the MR head 1 is set to the read track TR1 which is the target track.
Can be positioned at the center (Y) of the. The read track TR1 has a gap width T1 of the write gap 6.
By the relative size of the read gap width T2 with respect to
It is included in the range of the write track TR2.
The read gap of the MR head 1 is the read track TR.
The magnetic field from 1 is extracted and a read current is output to the read / write circuit 15 (step S17).

In this way, also in the second embodiment, the track shift amount TE existing between the write gap 6 and the read gap of the head 10 is obtained as in the case of the first embodiment. It is possible to position the write gap 6 or the read gap at the center of the target track by performing position correction.

[0032]

As described above in detail, according to the present invention, in the magnetic recording / reproducing apparatus using the head of the composite head structure, the read gap width is not made so small,
The write gap can be positioned at the center of the target track during the write operation, and the read gap can be positioned at the center of the target track during the read operation. Therefore, the reproduction signal level at the time of reading becomes small, and it is possible to surely realize the data writing operation and the data reading operation without causing a situation such as a decrease in the S / N ratio and the error rate of the device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a head positioning control device of a hard disk device according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining an operation according to the first embodiment.

FIG. 3 is a conceptual diagram for explaining the operation of the first and second embodiments.

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

FIG. 5 is a conceptual diagram for explaining a configuration of a head having a conventional composite head structure.

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

[Explanation of symbols]

1 ... MR head, 2 ... Thin film head, 6 ... Write gap, 10 ... Head, 14 ... Disk, 19 ... Servo circuit, 20 ... CPU, 22 ... ROM.

Claims (4)

[Claims] 1. A disk for recording data, a composite head structure having a data reading gap and a data writing gap, head means for recording and reproducing data on the disk, and a target track on the disk. When positioning the head means, a memory means for storing position correction data that is predetermined according to a track position deviation amount generated between the data read gap and the data write gap; When performing positioning control for positioning at the center, the positioning is performed so as to position the data read gap or the data write gap at the center of the target track based on the position correction data stored in the memory means. Head position determination for control correction processing A head positioning control device for a magnetic recording / reproducing apparatus, comprising: 2. A disk in which servo information including head positioning write burst data and read burst data is prerecorded, and a composite head structure having a data read gap and a data write gap, wherein A head unit for recording / reproducing data, and a positioning control for positioning the head unit at the center of the target track on the basis of the servo information read from the disk, and performing a data writing operation on the disk. The data write gap is positioned at the center of the target track based on the write burst data, and the data read gap is targeted based on the read burst data when a data read operation is performed from the disk. Position in the center of the track The head positioning control device for a magnetic recording and reproducing apparatus characterized by comprising a head positioning control unit. 3. A CDR type magnetic recording / reproducing apparatus for dividing a plurality of tracks on a disk into zones, which has a composite head structure having a data read gap and a data write gap, and records / reproduces data on / from the disk. And the position correction data determined in advance according to the track position deviation amount generated between the data read gap and the data write gap when the head means is positioned on the target track of the disk. The memory means stored for each of the data, and the data read gap or the data based on the position correction data stored in the memory means when executing the positioning control for positioning the head means at the center of the target track. Center the write gap at the target track A head positioning control device for a magnetic recording / reproducing apparatus, comprising: a head positioning control means for correcting the positioning control so as to perform positioning. 4. A CDR type magnetic recording / reproducing apparatus for dividing a plurality of tracks on a disk into zones, wherein servo information including head positioning write burst data and read burst data is prerecorded in each zone. Based on the servo information for each zone read from the disk, the head means for recording / reproducing data on / from the disk, and the composite head structure having a data read gap and a data write gap. Positioning control for positioning the head means at the center of the target track is performed, and the data write gap is positioned at the center of the target track based on the write burst data when the data write operation is performed on the disk. Read data from the disk And a head positioning control means for positioning the data read gap at the center of the target track based on the read burst data.