JP2926579B1 - Barkhausen noise removal method and magnetic disk drive to which this method is applied - Google Patents

Abstract

A method for effectively removing Barkhausen noise without reducing the overall data recording capacity of a recording medium and an apparatus to which the method is applied are provided. SOLUTION: In the method for removing Barkhausen noise by removing a current by flowing a current to an information recording head of the magnetic disk device, a current is supplied to the information recording head in a state where the information recording head is unloaded from the magnetic recording medium. Thus, Barkhausen noise generated when recording / reproducing information on / from a magnetic recording medium in a magnetic disk device is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing noise generated in a magnetic disk drive and a magnetic disk drive to which the method is applied, and more particularly to a Barkhausen noise generated when reproducing information from the magnetic disk drive. The present invention relates to a method for removing noise generated in a magnetic disk drive capable of suitably removing noise and a magnetic disk drive to which the method is applied.

[0002]

2. Description of the Related Art In recent years, as the capacity of a magnetic disk drive has been increased, a magnetoresistive element type head (MR) capable of obtaining a high reproduction output has been proposed as means for improving the magnetic recording density.
Head) has been developed. When such an MR head is used as a reproducing head, noise called Barkhausen noise occurs due to domain wall movement of the MR film. This Barkhausen noise is likely to occur after the information writing operation, and is superimposed on the reproduction signal. Therefore, if this noise occurs at a reference value or more, the data cannot be read correctly.
An error occurs.

As a method of removing such Barkhausen noise, it is conventionally known to supply a current to a recording head. This method is executed in an actual machine by moving a recording head out of a data area of a recording medium and performing writing here. According to such a method of passing a current through the recording head, Barkhausen noise can be removed very effectively.

[0004]

However, in the conventional method, since writing is performed outside the data area, a writing area dedicated to noise removal must be secured on the magnetic recording medium. Therefore, an area that can be used as a data area is occupied by an area for noise removal, which causes a problem that the data recording capacity of the entire recording medium is reduced.

The present invention has been made to solve such a problem, and a magnetic disk capable of effectively removing Barkhausen noise without reducing the overall data recording capacity of a recording medium. It is an object of the present invention to provide a method for removing Barkhausen noise generated in the apparatus and an apparatus to which the method is applied.

[0006]

In order to solve the above-mentioned problems, a method for removing Barkhausen noise according to the present invention is directed to a method for removing Barkhausen noise generated when recording / reproducing information on a magnetic recording medium in a magnetic disk drive. In the method of removing Barkhausen noise by removing a current by flowing a current through the information recording head of the magnetic disk drive, the current is passed through the information recording head while the information recording head is unloaded from the magnetic recording medium. It is characterized by removing Barkhausen noise.

As described above, in the method for removing Barkhausen noise according to the present invention, a current is applied to the information recording head while the information recording head is unloaded from the magnetic recording medium to remove Barkhausen noise. I have. Since the recording head is unloaded from the magnetic medium and energized, Barkhausen noise can be removed without affecting the magnetization state of the magnetic recording medium. Therefore, according to the method of the present invention, it is not necessary to set a write area for removing Barkhausen noise on the medium, and the data area on the magnetic recording medium can be fully used for writing data.

In the method of removing Barkhausen noise according to the present invention, the occurrence of a reading error when reading information from the magnetic recording medium is detected, and the Barkhausen noise is removed after the occurrence of the reading error. preferable.

As described above, Barkhausen noise is generated at the time of reading information. If an error occurs at the time of reading information, Barkhausen noise is removed, so that the cause of the error can be easily removed and accurate. Data can be read.

Further, in the method for removing Barkhausen noise according to the present invention, the position information of the recording head at the time of detecting the reading error is stored in a storage means, and the recording head is unloaded to reduce the Barkhausen noise. After the removal, it is preferable that the recording head is loaded on the magnetic information recording medium based on the position information of the recording head stored in the storage unit.

In the present invention, since the information recording head is unloaded from the magnetic recording medium to remove Barkhausen noise, the recording head is unloaded in order to resume the reading operation after the noise removing operation is completed. It is necessary to reload the magnetic recording medium from the load state. Therefore, when a reproduction error is detected, that is, by storing the position of the recording head at the time of unloading the recording head, the recording head is unloaded to remove Barkhausen noise, and then the reproduction head is returned to its original state. It can be easily loaded into a location.

A determination is made as to whether the detected read error is a servo read error or a data read error. If the read error is a servo read error, the cylinder position where the error occurred is stored in storage means. Preferably, after completion of the Barkhausen noise removing operation, the recording head is loaded onto the magnetic recording medium in accordance with the cylinder position information stored in the storage means. When the detected read error is a data read error, the cylinder position and the sector position where the error has occurred are stored in the storage unit, and after the Barkhausen noise removal operation is completed, the storage unit stores the data. It is preferable that the read head is loaded on the magnetic recording medium according to the stored cylinder position information and sector position information.

With this configuration, the recording head can be loaded at an appropriate position after removing Barkhausen noise in both cases of reading a servo signal and reading a data signal.

Incidentally, the recording head and the reproducing head are usually formed integrally, so that in such a case, the load / unload operation is performed simultaneously on both the recording head and the reproducing head.

Further, a magnetic disk drive for executing the Barkhausen noise elimination method of the present invention is an information recording / reproducing head for recording / reproducing information on / from a magnetic recording medium, and the information recording / reproducing head is connected to the magnetic medium. Means for loading / unloading the read / write head, and means for removing Barkhausen noise generated when the information recorded on the magnetic recording medium is read by the read / write head by applying a current to the read head. In the magnetic disk drive, the Barkhausen noise is performed in a state where the recording / reproducing head is unloaded from the magnetic recording medium.

Further, in the magnetic disk drive of the present invention, the recording / reproducing head loading / unloading means may include a carriage arm having at least an information recording / reproducing head mounted on a tip thereof, and a carriage arm having an information reproducing head mounted thereon. A rotating shaft provided at the opposite end, and a carriage arm rotating drive means for rotating the carriage arm about the rotating shaft; and rotating the carriage arm to record / reproduce the information. The head is configured to be loaded / unloaded with respect to the magnetic medium.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for removing Barkhausen noise generated in a magnetic disk drive according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a magnetic disk drive to which the method of the present invention is applied.
1 (a) shows a recording / reproduction for recording / reproducing information on a recording medium.
Figure 1 shows the read head loading onto the magnetic media.
(B) shows a state where the recording / reproducing head is unloaded from the magnetic medium.

As shown in FIG. 1, the magnetic disk drive 1 has a recording / reproducing head unit 3 composed of a recording head 3b for recording magnetic information on a magnetic recording medium 2 and a reproducing head 3a for reproducing. A carriage 4 supporting the recording / reproducing head 3 and a rotating shaft 5 provided at the other end of the carriage 4 are provided. The carriage unit 4 is configured to be rotatable around a rotation shaft 5.

In the head loading state shown in FIG.
The head unit 3 is on the magnetic recording medium 2. On the other hand, when the carriage unit 4 rotates about the shaft 5 and comes off the magnetic recording medium 2 as shown in FIG. It should be noted that even if a current flows through the recording head 3a in the head unloaded state, the magnetization state of the magnetic recording medium 2 does not change.

FIG. 2 is a block diagram showing a configuration of a drive circuit of the magnetic disk drive 1 shown in FIG. As shown in FIG. 2, the magnetic disk device 1 centrally controls the mutual operation between the storage unit 10 that stores the position information of cylinders and sectors on the magnetic recording medium 2 and each functional block in the magnetic disk device 1. The control circuit 11 exchanges recording / reproducing information with the control circuit 11, converts data sent from a higher-level device into a current and feeds it to the recording head 3 a, and also reads data read by the reproducing head 3 b from the magnetic recording medium 2 A recording / reproducing circuit unit 12 for amplifying the signal and converting it to a digital signal, and moving the recording / reproducing head unit 3 to a desired cylinder position
Alternatively, a positioning circuit unit 13 for moving the recording / reproducing head unit 3 to a load / unload position and stopping accurately at a desired position, and a servo current based on a servo signal output from the positioning circuit unit 13 A servo amplifier 14 to be generated and an actuator 15 that receives the servo current from the servo amplifier 14 and drives the recording / reproducing head unit 3 and the carriage unit 4 are provided.

The reproduction signal read by the reproduction head 3a includes the position signal of the recording / reproduction head 3 sent to the positioning circuit 13. In addition, the positioning circuit 13
Is configured to be controlled by a control signal from the control circuit 11. The servo section 1 is controlled by the positioning circuit section 13, the servo amplifier 14, and the actuator 15.
6.

[0022]

FIG. 3 is a flow chart showing the flow of processing in the control circuit unit 11 when an error occurs due to Barkhausen noise during data reproduction in the magnetic disk drive 1. As described above, Barkhausen noise is generated in a reproduced signal and not generated in a recorded signal. Therefore, when the amount of Barkhausen noise exceeds a certain value, an error occurs when the reproducing head 3a reproduces a servo signal or reproduces a data signal.

In the control circuit section 11, the reproducing head 3a
If an error occurs when reproducing a servo signal or a data signal (step A1), it is determined whether this error is a servo read error or a data read error (step A2). If the error is a servo read error, the cylinder position where the error has occurred is stored in the storage unit 10 (step A3). If the error is a data read error, both the cylinder position where the error occurred and the sector position are stored in the storage unit 10 (step A4).

Next, regardless of the type of error, the servo unit 16 is driven to perform an unload operation of the recording / reproducing head unit 3 (step A5). When the recording / reproducing head section 3 is completely separated from the magnetic medium 2 and becomes in a state where the current flowing through the recording head 3b does not affect the magnetization state on the medium 2, the recording / reproducing circuit section 12 is driven to perform recording. A current is applied to the head 3b for a predetermined period to remove Barkhausen noise (step A6). Stop the current (step A
7) The servo unit 16 is driven again to perform the loading operation of the recording / reproducing head unit 3 (step A8).

When the recording / reproducing head unit 3 loads onto the recording medium 2, the cylinder position stored in the storage unit 10 in step A3 or step A4 is called (step A9), and based on this information, the servo unit 16 is read. Is driven to perform a seek (step A10).

Here, it is determined again whether the error is a servo read error or a data read error (step A11). If the error is a servo read error, the process ends (step A14). On the other hand, if the error is a data read error, the storage unit 1
0 (step A1).
2) The data at the cylinder / sector position, which was not read previously, is read again by the recording / reproducing circuit unit 12 (step A13), and the process ends (step A14).

[0027]

As described in detail in the above embodiments, according to the noise elimination method of the present invention, when a reproduction error occurs, at least the recording head is unloaded from the magnetic medium and the recording head is unloaded. An electric current is applied to remove Barkhausen noise. Since the recording head is unloaded and energized, noise can be removed without affecting the magnetization state of the magnetic medium by the current flowing through the recording head. Therefore, according to the present invention, it is not necessary to set a write area for removing Barkhausen noise on the recording medium, and the recording capacity on the magnetic recording medium can be increased by that much.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a magnetic disk drive according to the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a magnetic disk drive according to the present invention.

FIG. 3 is a flowchart showing a flow of processing in a control circuit for removing Barkhausen noise according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 magnetic disk device 2 magnetic recording medium 3 head unit 4 carriage unit 5 axis 10 storage unit 11 control circuit unit 12 recording / reproducing circuit unit 13 positioning circuit unit 14 servo amplifier 15 actuator 16 servo unit

Claims (10)

(57) [Claims] 1. A method for removing Barkhausen noise which removes Barkhausen noise generated when recording / reproducing information on / from a magnetic recording medium in a magnetic disk drive by applying a current to an information recording head of the magnetic disk drive. 3. The method for removing Barkhausen noise according to claim 1, wherein a current is applied to the information recording head while the information recording head is unloaded from the magnetic recording medium to remove the Barkhausen noise. 2. The method of removing Barkhausen noise according to claim 1, wherein an occurrence of a reading error when reading information from said magnetic recording medium is detected, and said Barkhausen noise is removed after the occurrence of said reading error. A method of removing Barkhausen noise. 3. The method of removing Barkhausen noise according to claim 2, wherein the position information of the recording head at the time of detecting the read error is stored in a storage unit, and the recording head is unloaded so that the bulk information is unloaded. A method for removing Barkhausen noise, comprising: after removing Hausen noise, loading the recording head onto the magnetic information recording medium based on the positional information of the recording head stored in the storage unit. 4. The method for removing Barkhausen noise according to claim 3, wherein the determination is made as to whether the detected read error is a servo read error or a data read error, and the read error is determined as a servo read error. In the case of, the cylinder position where the error has occurred is stored in the storage means, and after the operation of removing the Barkhausen noise is completed, the recording head is subjected to the magnetic recording according to the cylinder position information stored in the storage means. A method for removing Barkhausen noise, wherein the method is loaded on a medium. 5. The method of removing Barkhausen noise according to claim 3, wherein it is determined whether the detected read error is a servo read error or a data read error, and the read error is a data read error. In the case of, the cylinder position and the sector position where the error has occurred are stored in the storage means, and after the operation of removing the Barkhausen noise is completed, according to the cylinder position information and the sector position information stored in the storage means. A method for removing Barkhausen noise, wherein the recording head is loaded on the magnetic recording medium. 6. The method of removing Barkhausen noise according to claim 1, wherein said recording head is integrally formed with a reproducing head, and said loading and unloading operations are performed with said recording head. A method for removing Barkhausen noise, wherein the method is performed simultaneously for both reproduction heads. 7. An information recording / reproducing head for recording / reproducing information on / from a magnetic recording medium, means for loading / unloading the information recording / reproducing head on / from the magnetic medium, and the magnetic recording / reproducing head for recording / reproducing information. Means for removing Barkhausen noise generated when information recorded on a recording medium is read out by applying a current to the recording head, wherein the Barkhausen noise is reduced by the recording head. A magnetic disk drive characterized in that the processing is performed in a state of being unloaded from the magnetic recording medium. 8. The magnetic disk drive according to claim 7, wherein said apparatus further comprises an error detecting means for detecting occurrence of an error during information reproduction, and wherein said error detecting means detects an error during information reproduction. A magnetic disk drive wherein the recording head is later unloaded to remove the Barkhausen noise. 9. The magnetic disk drive according to claim 8, wherein said apparatus further comprises a head position storage means for storing a position of said information recording / reproducing head on a magnetic medium, and wherein said error detecting means stores said information. When an error during reproduction is detected, the position of the information recording / reproducing head on the magnetic medium at that time is stored in the head position storage means, and after the Barkhausen noise is removed, the head A magnetic disk drive wherein the information recording / reproducing head is loaded onto the magnetic medium in accordance with the position information stored in the position storage means. 10. The recording / reproducing head loading / unloading means is provided at a carriage arm having at least an information recording / reproducing head mounted at a front end and at an end opposite to an end at which the information recording / reproducing head is mounted. And a carriage arm rotation driving means for rotating the carriage arm about the rotation axis. The information recording / reproducing head is moved to the magnetic medium by rotating the carriage arm. 10. The magnetic disk drive according to claim 7, wherein the magnetic disk drive is configured to be loaded / unloaded.