JP2003085704A - Disk device and head polarity switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device which accurately reads servo data by detecting polarities of magnetic heads mounted on the magnetic disk device and correctly setting the polarity by magnetic heads. SOLUTION: In a magnetic disk device 1 which reads out a reproducing signal recorded on a magnetic disk 2 with a prescribed polarity and reproduces information on the basis of the reproducing signal read out with the prescribed polarity, the polarity of the reproducing signal is detected by a read/write channel 136, and the polarity is inverted by a polarity switching circuit 136a in accordance with the detected polarity so that the reproducing signal may have a prescribed polarity, and this the magnetic disk device can accurately read out servo data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk device that uses both a pre-servo write system and a synchronous servo system, and a head polarity switching method for a head mounted in the disk device.

[0002]

2. Description of the Related Art In a magnetic disk device that does not use the pre-servo write method, the combination of the magnetic disk and the magnetic head does not change, and the signal polarities read by the magnetic head are always the same. However, in the pre-servo write method, since the magnetic head at the time of servo write and the built-in head are different, the signal polarities read by the heads may be reversed when the respective heads are used differently.

When the read channel used is a system for discriminating the signal polarity such as a synchronous servo system, there is a problem that the servo data cannot be detected if the signal polarity is reversed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and pre-records servo data before mounting it on a magnetic disk device (pre-servo write). By detecting the combination of the head polarities of the magnetic heads mounted on the magnetic disk device to which this disk is attached and setting the polarity setting of the read channel correctly for each magnetic head, the servo data can be read accurately. It is an object of the present invention to provide a magnetic disk device that can be used for other purposes.

[0005]

A magnetic disk device of the present invention is a disk which reads a reproduction signal recorded on a recording medium with a predetermined polarity and reproduces information based on the reproduction signal read with a predetermined polarity. The apparatus comprises a polarity detecting means for detecting the polarity of the reproduction signal, and a polarity control means for inverting the reproduction signal so as to have the predetermined polarity according to the polarity detected by the polarity detection means. It is characterized by.

By providing the magnetic disk device with such polarity control means, particularly in a device in which servo data is recorded on a disk mounted in the device by the pre-servo write method, the head at the time of servo writing and the disk It is possible to prevent the discrepancy between the polarity of the signal read from the head and the polarity of the head that may occur due to different heads installed in the built-in device and to set the signal polarity correctly, so the servo data can be read accurately in the magnetic disk device. That is, the head can be accurately positioned.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a magnetic disk device 1 as an example of a disk device according to an embodiment of the present invention. The magnetic disk device 1 is a hard disk device in which two fixed disks 2 are mounted. The two fixed disks 2 are attached to a spindle motor 3 and are controlled to rotate at a predetermined rotation speed when the magnetic disk device 1 operates. The magnetic disk device 1 includes an actuator 6 in which a suspension in which a magnetic head 4 such as an MR head is mounted and a thin plate arm made of stainless steel are laminated.
And a voice coil motor 7 for driving the actuator 6. As described above, the mechanism that constitutes the magnetic disk device 1 is housed in the housing and is referred to as a mechanism portion.

The casing is composed of a cover 9 which is an upper lid and a housing 8 which is a storage container.
It is fixed to the housing 8 by this, and the housing 8 and the cover 9 form a closed space. The housing 8 and the cover 9 are in close contact with each other with a gasket (not shown) interposed therebetween in order to improve the airtightness inside the housing 8 covered with the cover 9.

Further, a printed circuit board 11 is arranged outside the housing constituted by the housing 8 and the cover 9, that is, in the present embodiment, on the side opposite to the cover 9 of the housing. A control circuit (I) for controlling the spindle motor 3, the magnetic head 4, the voice coil motor 7, and the like, which are the mechanical parts of the magnetic disk device 1, is provided on the printed circuit board 11.
A C circuit) 13, a DRAM that is a memory, a hard disk controller (HDC), and a servo control circuit are mounted and wired, and are electrically connected to each mechanical unit in the housing by a connector 12.

FIG. 2 is a block diagram of the magnetic disk device according to this embodiment.

A magnetic disk 2 as a data recording medium
Is rotated by a spindle motor (SPM) 3. The magnetic disk 2 is movably arranged on the magnetic disk 2.
The magnetic head 4 for recording or reproducing data is controlled by a rotary actuator 6 driven by a voice coil motor (VCM) 7.

The signal reproduced by the magnetic head 4 is
Read channel 1 amplified by head amplifier 132
Sent to 36.

FIG. 3 shows an example of the servo signal waveform SS1 sent to the read channel 136. Servo signal SS1
Is a servo preamble portion 41, a servo mark portion 42,
It is composed of a sector code section 43, a cylinder code section 44, and the like. The servo preamble part 41 is a signal of a constant frequency, and the read channel 136 decodes the following sector code part 43, cylinder code part 44, etc. by detecting the servo mark part 42 of a specific pattern of 0 and 1 which follows. To start.

Based on the obtained sector code 43, cylinder code 44, etc., the servo processing circuit 137 and the CPU 13 perform an operation, and send the operation result to the VCM driver 134 to control the VCM 7.

In this way, the magnetic head 4 is sought to the target track and the positioning of the magnetic head 4 is realized.

The servo signal SS1 is supplied to the magnetic disk device 1
Is written on the magnetic disk 2 concentrically in the manufacturing stage of. Conventionally, in a state where the magnetic disk 2 and the magnetic head 2 of the magnetic disk device 1 are incorporated, the magnetic disk device 1 is mounted by a push pin of an external servo write device.
The servo signal SS1 was written while pressing and moving the position of its own magnetic head 2.

In recent years, a method of writing a servo signal using a write head of a dedicated servo signal writing device (referred to as a single-plate servo writer) before the magnetic disk 2 is incorporated into the magnetic disk device 1 has been adopted. It may be taken (this system is called a pre-servo system). In this case, the magnetic head 2 used for writing is different from the magnetic head 2 incorporated in the magnetic disk device 1.

If the magnetic heads 2 have the same specifications, the polarity of the magnetic head 2, that is, the signal polarity when the written servo signal SS1 is read out does not change. However, in the case of the magnetic heads 2 having different specifications, the signal polarity may be inverted (FIG. 4: SS2). When the read channel 136 to be used is a system for discriminating the signal polarity such as a synchronous servo system, the servo data SS1 cannot be detected if the signal polarity is inverted.

Normally, the read channel 136 for the synchronous servo is provided with a polarity switching function 136a, and the servo signal S can be selected by selecting the correct polarity.
It is possible to determine S1. Therefore, it is necessary to set the correct polarity depending on the combination of the polarity of the pre-servoed servo signal SS1 and the polarity of the magnetic head 2 of the magnetic disk device 1.

Therefore, in the embodiment of the present invention, when the combination of the polarity of the pre-servoed servo signal SS1 and the polarity of the magnetic head 2 of the magnetic disk device 1 can be grasped in advance, each magnetic head 2 is read. Channel 136
It is possible to read the correct servo signal SS1 by providing the polarity setting of No. 1 in the ROM 141 as the polarity table 71 and setting the polarities of the read channels 136 at the same time when switching the magnetic head 2.

An example of the polarity table 71 is shown in FIG. The polarity table 71 is a table in which the polarity p (h) of the read channel 136 is set corresponding to the number h of the magnetic head 4 mounted on the magnetic disk device 1.

A method of setting the polarity of the read channel 136 using the polarity table 71 will be described below with reference to the flowchart of FIG.

The CPU 13 determines whether a read / write command for requesting data read or write is received from the host device such as an external computer to the magnetic disk device 1 (step S1).

Next, the number h of the magnetic head 2 for which a read / write request has been made is temporarily held (step S2).

Thereafter, the polarity p (h) of the read / write channel 136 corresponding to the head number h is referenced from the polarity table 71 stored in advance in the ROM 141, and this polarity p (h) is set in the read / write channel 136. Yes (step S3).

Next, the seek operation of the magnetic head 2 is executed by using the set polarity p (h), and the read / write command requested by the host is executed (step S).
4).

After that, it is judged whether or not there is a switching request for the magnetic head 4 (step S5), and if there is no switching request, the process is terminated.

When there is a switching request for the magnetic head 4 in the previous step S5, the process is returned to step S2, the head number for which the switching is requested is registered as h, and the processes from step S3 to step S4 are executed thereafter. And an appropriate polarity p of the read / write channel 136 corresponding to the magnetic head 4 selected in response to the read / write command.
Set (h).

Further, the pre-servoed servo signal SS1
When the combination of the polarities of the magnetic head 4 and the magnetic head 4 of the magnetic disk device 1 cannot be grasped in advance, that is, the correspondence between the polarities of the magnetic head 4 and the read / write channel 136 cannot be recorded in advance as the polarity table 71, the magnetic At the time of starting the disk device 1, an attempt is made to read the servo signal while switching the polarity setting, and the polarity set value for which the servo data is successfully read is set as the correct polarity of the magnetic head 4 of the corresponding magnetic head 4 and read / write channel 136. By storing the polarities in the polar table 71 and setting the polarities according to the polar table 71 from the next time, the magnetic head 4 can accurately seek to the target track even when the polarities of the magnetic head 4 are unknown. It will be possible.

As described above, a method of obtaining the polarity of the magnetic head 4 when the polarity of the magnetic head 4 is unknown will be described below with reference to the flowchart of FIG.

First, in order to determine whether the polarity of the head number 0 of the magnetic head 4 is proper, the head number h is set to 0.
Is set (step S10).

Next, the seek operation is executed with the head number h (step S20). At this time, it is determined whether the magnetic head 4 succeeds in the seek operation without any problem (step S30). If the seek operation succeeds without any problem, 0 is associated with the polarity p (h) of the read / write channel 136 corresponding to the current magnetic head number h (step S40).

Next, the head number is incremented from 0 (step S50), and it is then determined whether or not the head number has reached the number of heads of the magnetic disk device 1 (step S60). That is, the polarity determination (steps S20 to S50) for one magnetic head described above is executed for the number of heads included in the magnetic disk device 1.

If the seek operation is not successful in step S30, the process proceeds to step S70 to invert and set the polarity of the read / write channel 136.

After this polarity reversal, the seek operation of the head h is executed again (step S80).

Then, the magnetic head 4 judges whether or not the seek operation succeeds without any problem (step S).
90). Here, if the seek operation succeeds without any problem, 1 is associated with the polarity p (h) of the read / write channel 136 corresponding to the current magnetic head number h (step S100). That is, the table value is set so that the head polarity is reversed.

Then, the process proceeds to step S50 to determine the polarity of the next head.

If the seek operation is not successful in step S90, it may be possible that the seek could not be performed for another reason. Therefore, retry processing or the like may be performed, but the seek cannot be finally performed. If seek NG
Becomes

By the above processing, the polarities of the read / write channels 136 corresponding to the polarities of the plurality of magnetic heads 4 mounted on the magnetic disk device 1 are created as a correspondence table (polarity table 71) when the magnetic disk device 1 is started. can do.

In the present embodiment, the magnetic disk device has been described as an example of the polarity determination process, but the polarity determination process is not limited to this.

In the present embodiment, the polarity table is created when the magnetic disk device is started up. However, the present invention is not limited to this, and during the main processing of the magnetic disk device, for example, a command is received from the host device for a certain period of time. The above-mentioned polarity table creation process may be executed when the state of not performing continues.

[0043]

As described above in detail, according to the present invention, the servo data is recorded in advance before being mounted on the magnetic disk device (pre-servo write), the polarity of the servo data of the disk, and the magnetic disk device to which this disk is mounted. By detecting the combination of head polarities of the magnetic heads mounted on the magnetic head and setting the polarity setting of the read channel correctly for each magnetic head, it becomes possible to read the servo data accurately.

[Brief description of drawings]

FIG. 1 is an exploded perspective view illustrating a structure of a magnetic disk device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a circuit configuration of the magnetic disk device according to the embodiment of the invention.

FIG. 3 is a waveform for explaining the polarity of a servo signal of the magnetic disk device according to the embodiment of the invention.

FIG. 4 is a waveform diagram illustrating a servo signal having polarity inversion according to an embodiment of the present invention.

FIG. 5 is an example of a polarity table according to the embodiment of the present invention.

FIG. 6 is a flowchart illustrating a polarity setting and seek operation of the magnetic disk device according to the embodiment of the invention.

FIG. 7 is a flowchart illustrating a polarity table creating operation of the magnetic disk device according to the embodiment of the invention.

[Explanation of symbols] 1 ... Magnetic disk unit 2 ... Magnetic disk 3 ... Spindle motor 4 ... Magnetic head 5 ... Axis 6 ... Actuator 7 ... Voice coil motor (VCM) 8 ... Housing 9 ... Cover 10 ... FPC 11 ... Printed circuit board 12 ... Connector 13 ... CPU 14 ... screw 131 ... Spindle motor (SPM) driver circuit 132 ... Head amplifier circuit 133 ... SPM D / A converter 134 ... Voice coil motor (VCM) driver circuit 135 ... D / A converter for VCM 136 ... Read / write channel 136a ... Polarity switching circuit 137 ... Servo processing circuit 138 ... Disk controller (HDC) 139 ... Buffer memory 140 ... RAM 141 ... ROM 71 ... Polarity table

Claims (6)

[Claims] 1. A disk device for reading a reproduction signal recorded on a recording medium with a predetermined polarity and reproducing information based on the reproduction signal read with a predetermined polarity, the polarity detecting the polarity of the reproduction signal. A disk device comprising: a detection unit; and a polarity control unit for inverting the reproduction signal so as to have the predetermined polarity according to the polarity detected by the polarity detection unit. 2. The disk apparatus according to claim 1, further comprising level correction means for correcting the level of the output reproduction signal of the polarity control means according to the polarity detection result of the polarity detection means. 3. The disk device according to claim 1, wherein the polarity detecting means detects the amplitude of the reproduction signal and determines the polarity of the reproduction signal according to the detected component. 4. The disk device according to claim 1, wherein the polarity detection means detects an integrated value of the reproduction signal and determines the polarity of the reproduction signal according to the detected component. 5. The disk device according to claim 1, wherein the polarity detection means detects vertical asymmetry of the reproduction signal and determines the polarity of the reproduction signal according to the detection result. . 6. Amplification means for amplifying the reproduction signal, and an amplification rate control signal for generating an amplification rate control signal for controlling an amplification rate of the amplification means according to an amplification result of the amplification means and supplying the amplification rate control signal to the amplification means. 3. The disc according to claim 1, further comprising: a means for detecting the polarity of the reproduction signal according to the amplification factor control signal generated by the amplification factor control means. apparatus.