JP2000306346A - Magnetic disk apparatus and positioning method of magnetic disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of a seek error due to the influence of a defect existing in a substituted track by substituting a cylinder, which cannot be positioned, for a defect track, retreating a defect sector on the basis of information on a defect position, and performing a seek operation. SOLUTION: When a defect exists in a track (n+4), the track (n+4) is regarded as unusable so as to be replaced with another track, and it is possible to prevent that a track cannot be positioned. When a track B is taken while a part between adjacent tracks is seeked, a seek operation is started after a write operation to a track (n+3) is finished. At this time, a seek starting position is deviated while the track (n+4) passes a defect area, and, e.g. a track C is taken. Thereby, it is possible to prevent a seek error which is generated when the track (n+4) passes the defect area. In addition, even in the starting sector of a track (n+5), the seek starting position is deviated in advance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive and a method for positioning a magnetic disk drive.
The present invention relates to a magnetic disk device that performs a seek operation and a positioning operation based on servo information recorded on a data surface on a magnetic disk, and a method of positioning a magnetic disk device.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk drive that performs a seek operation and a positioning operation based on servo information recorded on a data surface on a magnetic disk has a servo function that is recorded on a data surface during a seek operation and a positioning operation. A seek error occurs when information is continuously in error. In such a case, the cause of the continuous error of the servo information may be a defect of the magnetic disk medium. That is, there may be a case where a large medium defect causing a continuous error exists on a circumferential track of the magnetic disk, or a case where a scratch occurs on a circumferential track of the magnetic disk. As described above, since a track including a medium defect cannot be positioned, the track is registered as a track that cannot be positioned at the time of factory inspection, and a replacement process for replacing another track is executed.

That is, a track including a medium defect is not used for read processing and write processing, thereby preventing occurrence of a positioning error. Further, when a track that cannot be positioned for a later reason occurs after shipment from the factory, the track is registered as a defective track, and a replacement process for replacing another unused spare track is executed.

On the other hand, as another magnetic disk device, a magnetic disk device disclosed in Japanese Patent Application Laid-Open No. 7-93769 is known. In the magnetic disk device disclosed in the publication, a technique of performing read processing and write processing while avoiding a defective portion without replacing a defective track is applied. That is, when there is a defective track, a seek operation is performed to a normal sector after the defect, and the head is evacuated before reading the defective sector.

[0005]

In the above-mentioned conventional magnetic disk drive, even if a defective track is replaced on the magnetic disk, a problem may occur if a seek occurs across the track. In other words, when a seek occurs across a defective track or when the track crosses at a high speed, no problem occurs because only one defective sector is read even if the defective sector is bad. However, when a low-speed seek that crosses the corresponding track, mainly when a seek between adjacent tracks occurs, a problem occurs because the defective sector of the corresponding track may be continuously read during the seek.

Normally, when a seek occurs between adjacent tracks, a write operation or a read operation of continuous data is being performed, and the condition under which seek between adjacent tracks occurs (seek start position) is almost a fixed condition. Becomes At this time, if the timing at which the seek between adjacent tracks occurs is shifted from the defective sector, no problem occurs. However, when the seek timing collides with the defect position of the defective track, a seek error frequently occurs. If an error occurs here, an error recovery process is performed, and a retry process for reseeking to a target track is performed.

If the retry process occurs at a high frequency, the data write or read operation is delayed. In such a case, in the conventional magnetic disk drive,
When an error occurs above a certain standard, the corresponding device is treated as defective and measures such as replacement of the magnetic disk device main body are performed.

On the other hand, in JP-A-7-93769,
Since a defective track is not replaced, if there is a sector where a read error or write error occurs in the relevant track, the retry operation of the error sector is usually performed while positioning the track on which the error occurred. In this publication, a seek error occurs because a defective sector is read. Further, in order to prevent a seek error from occurring, it is necessary to always perform a save operation to another track. Further, in the publication, there is a problem that the seek process is complicated because the process varies depending on the seek method.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and reduces the occurrence of a seek error due to the influence of a defect existing in a track subjected to a replacement process, improves the throughput performance of data read / write operation, and It is an object of the present invention to provide a magnetic disk drive and a method of positioning the magnetic disk drive, which can relieve a defective magnetic disk drive main body.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a defective track replacing means for replacing a cylinder which cannot be positioned as a defective track, and a position of a defective sector on the defective track in advance. Defect position storage means for storing the defect sector information as defect position information, and performing a seek operation for retracting a defective sector based on the defect position information and performing a seek operation when passing through a cylinder which cannot be positioned at a low speed seek. Means.

[0011] The invention according to claim 2 is based on claim 1.
Wherein the seek operation executing means changes a sector start position of a cylinder adjacent to the defective track based on defect position information indicating a position of a defective sector on the defective track.

Further, according to a third aspect of the present invention, in the magnetic disk drive according to any one of the first and second aspects, the defective track replacement means includes a track whose positioning is impossible or a frequency of occurrence of a positioning error is high. It is configured to detect a track.

Further, according to a fourth aspect of the present invention, in the magnetic disk drive according to any one of the first to third aspects, the defective track replacing means includes a track that cannot be positioned or a frequency of occurrence of a positioning error is high. When a track is detected, a substitute process for substituting a spare track is executed.

Further, according to a fifth aspect of the present invention, in the magnetic disk drive according to any one of the first to fourth aspects, the defect position storage means includes a track or a track on which the defective track replacement means cannot position. When a track having a high positioning error frequency is detected, the position information of this track and the sector in which the error has occurred is stored as defect position information.

In the magnetic disk drive according to the present invention configured as described above, when the magnetic disk drive is shipped from the factory, a track that cannot be positioned or a track with a high frequency of positioning errors and its error occur by a predetermined inspection method. Detect sector. Then, the track and the sector are stored in the defect position storage means. The storage in the defect position storage means corresponds to registering as a track that does not use the corresponding track and sector,
The defective track substituting means performs a substituting process of substituting the registered track for another track.

Further, if a track that cannot be positioned later or has a high frequency of occurrence of a positioning error occurs after shipment from the factory, the defective track replacement means performs replacement processing on the spare track. In such cases,
The defective track replacement means detects a track that cannot be positioned or a track with a high frequency of occurrence of a positioning error, and stores the track that cannot be positioned or a track with a high frequency of a positioning error as an error track and an error sector in the defect position storage means. Remember.

In performing seek between adjacent tracks, when writing / reading continuous data, when passing through an error track on which replacement processing has been performed, it is determined whether or not to pass through an error sector of the error track. It is calculated from the stored defect position information. When passing through an error sector, a seek is started after placing a weight so as not to pass through the error sector. In this case, the sector start position of the seek destination is shifted from the normal position by the time set by the weight. That is, when the magnetic head crosses a defective track, it is possible to prevent the magnetic head from passing through the defective sector. Therefore, occurrence of a seek error can be avoided. As a result, continuous reading / writing of data is not interrupted, and throughput performance in reading / writing data can be improved. Further, by shifting the sector start position of the seek destination, the occurrence of rotation waiting can be reduced.

As described above, the method of executing the seek operation and the positioning operation based on the servo information recorded on the data surface on the magnetic disk is not necessarily limited to a physical device, and the method of functioning as a method is not limited to a physical device. Easy to understand. For this reason, the invention according to claim 6 is a method of positioning a magnetic disk drive that performs a seek operation and a positioning operation based on servo information recorded on a data surface on a magnetic disk, wherein a cylinder that cannot be positioned is replaced with a defective track. A defective track substituting step, a defect position storing step of storing the position of a defective sector on the defective track as defect position information, and the defect position information when passing through a cylinder that cannot be positioned at a low speed seek. And a seek operation execution step of executing a seek operation by retracting a defective sector based on the above. In other words, there is no difference in that the present invention is not necessarily limited to a substantial device and is also effective as a method.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a magnetic disk drive according to an embodiment of the present invention.
In FIG. 1, a magnetic disk drive 1 includes a magnetic disk 2
A magnetic head 3, a magnetic circuit 4, a read / write circuit 5, a positioning control circuit 6, a signal modulation / demodulation circuit 7,
It comprises a microcomputer 8 and a disk control circuit 9.

Here, the disk control circuit 9 receives data to be written on the magnetic disk 2 from a predetermined host device 10 and supplies the data to a signal modulation / demodulation circuit 7 for modulating the data into a signal suitable for magnetic recording. Then, the signal modulation / demodulation circuit 7
Modulates the received data into a signal suitable for magnetic recording and supplies the signal to the read / write circuit 5. Then, the read / write circuit 5 writes the data supplied from the signal modulation / demodulation circuit 7 to the magnetic disk 2 via the magnetic head 3 while driving the magnetic head 3.

At this time, before data is written, the magnetic head 3 is positioned at a predetermined position on the magnetic disk 2. Such positioning is performed as follows. First, a positioning servo information signal recorded in advance on the magnetic disk 2 is read by the magnetic head 3 and supplied to the read / write circuit 5. And
In the read / write circuit 5, the servo information signal is amplified at a predetermined amplification rate. Thereafter, the signal is transmitted to the signal modulation circuit 7, and the signal modulation / demodulation circuit 7 demodulates the servo information signal. The demodulated servo information signal is then supplied to a positioning control circuit 6, which drives the magnetic circuit 4 based on the servo information signal, that is, the positioning signal, to move the magnetic head 3 to the magnetic disk. Positioning is performed at the second predetermined position.

The magnetic disk 2 of the magnetic disk drive 1
In the reproduction of the data recorded in the above, the same positioning control as in the above-described writing is executed. Therefore, the magnetic head 3 is positioned at a predetermined position on the magnetic disk 2, reads out and reproduces predetermined data on the magnetic disk 2, and supplies the data to the read / write circuit 5. And
The read / write circuit 5 amplifies the reproduction signal input from the magnetic head 3 at a predetermined amplification rate and supplies the signal to the signal modulation / demodulation circuit 7.

The signal modulation / demodulation circuit 7 to which the reproduced signal is input is
By demodulating data from the reproduced signal, the original data is restored and supplied to the disk control circuit 9 as reproduced data. Then, the disk control circuit 9 supplies the restored reproduced data to the host device 10. Here, when executing the data write and read processing, the microcomputer 8 sends an operation instruction for drive control for realizing a predetermined seek operation in the magnetic head 3 to the positioning control circuit 6 and the disk control circuit 9. Supply.

Next, the operation of the present embodiment having the above configuration will be described. FIG. 2 is an enlarged view of a part of the magnetic disk 2. Here, the tracks n to n + 7 are formed concentrically on the medium of the magnetic disk 2. In the figure, data is previously written on the medium in the servo zone, and by reproducing the data, the magnetic head 3 is positioned at a predetermined position. In the data zone, writing and reading of predetermined data are executed. Here, usually, continuous data is continuously written in the data zone on the track.

At this time, if it is assumed that data is written in the direction in which n increases from n on the track, the magnetic head 3 seeks to track (n + 1) after one round of data is written on track n. After the positioning is completed, the track (n +
Data is written in 1). Here, normally, the start sector of the track between adjacent tracks is shifted by the seek time of the magnetic head 3 to reduce the rotation waiting time in the case of adjacent seek.

Here, consider the case where the track (n + 4) in FIG. 2 has a defect. In such a case, this track (n
In the case of +4), since the sector corresponding to the servo zone cannot be read continuously, positioning to a predetermined track is impossible.

At this time, by making track (n + 4) unusable and replacing it with another track, it is possible to avoid that positioning cannot be performed. here,
Consider a case where a locus B shown in FIG. 2 is taken when seeking between adjacent tracks. In such a case, the track (n + 3)
After the writing to the memory is completed, a seek operation is started. Here, it is assumed that a predetermined sector of the track (n + 4) has a defect and a defective area is formed. In such a situation, the vehicle passes through this defective area during positioning on the next track (n + 5). At this time, the track (n + 4) recorded in the servo zone of the defective area
A seek error occurs because the servo information cannot be read.

Here, since there is no problem unless the trajectory positioned on the track (n + 5) collides with the defective area on the track (n + 4), when the writing on the track (n + 3) is completed, the defective area on the track (n + 4) is deleted. Consider shifting the seek start position by the passing time. For example, the trajectory C shown in FIG. This makes it possible to avoid a seek error that occurs when the track (n + 4) passes through the defective area. Here, the start sector of the track (n + 5) is also shifted in advance by the shift time of the seek start position described above, so that the rotation waiting time on the track (n + 5) can be avoided.

The same applies to the case where predetermined data written in the data zone of the magnetic disk 2 is read. In addition to the seek between adjacent tracks, when the magnetic head 3 passes through a track having a defective area at a high speed, that is, when the track A shown in FIG. 2 is taken, the defective area exists even when the magnetic head 3 passes through the defective area. There is no problem because the track (n + 4) is not read continuously.

As described above, by performing a process for avoiding a seek operation passing through a track having a defective area at the time of seeking between adjacent tracks, in the process of writing / reading continuous data to / from the data zone, data transfer is performed. Can be completed without interrupting the process. This processing can be realized by simple processing because it is necessary to hold only the time required for the wait as a parameter whether or not there is a wait at the start of seek when passing through the substitute track, and if a wait is required. It becomes possible to do.

[0031]

As described above, according to the present invention, it is possible to avoid the occurrence of a seek error even at the time of a seek that passes through a track having an unpositionable defect. It is possible to provide a magnetic disk drive that can avoid a decrease in the write / read throughput performance and can obtain the same effect when a track whose positioning cannot be performed later is replaced. According to the second aspect of the present invention, since the sector start position is shifted by the weight, access to the defective sector is eliminated.

Further, according to the third aspect of the present invention,
It is possible to detect a non-positionable track or a track with a high frequency of occurrence of a positioning error that occurs later after factory shipment. Furthermore, according to the invention of claim 4, it is possible to replace a track that cannot be positioned or that has a high frequency of positioning errors, which occurs late after shipment from the factory, with an unused spare track. Furthermore, according to the invention of claim 5, it is possible to register a non-positionable track that occurs late after shipment from the factory or a track with a high frequency of positioning errors, which can be referred to in a subsequent seek operation. Will be possible.

Further, according to the invention of claim 6,
It is possible to avoid the occurrence of a seek error even during a seek that passes through a track where an unpositionable defect exists, so that it is possible to avoid a decrease in the data write / read throughput performance due to the seek error and to provide a later method. Thus, it is possible to provide a magnetic disk drive positioning method capable of obtaining the same effect when a track whose positioning cannot be performed is replaced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a block diagram of a magnetic disk drive.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnetic disk device 2 magnetic disk 3 magnetic head 4 magnetic circuit 5 read / write circuit 6 positioning control circuit 7 signal modulation / demodulation circuit 8 microcomputer 9 disk control circuit 10 host device

Claims (6)

[Claims] A defective track replacing means for replacing an unpositionable cylinder as a defective track; a defective position storing means for storing a position of a defective sector on the defective track in advance as defect position information; A magnetic disk drive comprising: a seek operation executing means for executing a seek operation by retracting a defective sector based on the defect position information when passing through a cylinder at a low speed seek. 2. The magnetic disk drive according to claim 1, wherein said seek operation executing means determines a sector start position of a cylinder adjacent to the defective track based on defect position information indicating a position of a defective sector on the defective track. A magnetic disk drive characterized by changing. 3. The magnetic disk drive according to claim 1, wherein said defective track replacement means detects a track that cannot be positioned or a track with a high frequency of positioning errors. Disk device. 4. The magnetic disk drive according to claim 1, wherein said defective track replacement means detects a non-positionable track or a track with a high frequency of positioning errors, and sets a spare track. A magnetic disk drive, which executes an alternative process to substitute for a disk drive. 5. The magnetic disk drive according to claim 1, wherein said defective position storage means is a track on which said defective track replacement means cannot be positioned or a track having a high frequency of positioning errors. , The position information of this track and the sector in the track where an error has occurred is stored as defect position information. 6. A method for positioning a magnetic disk device, which performs a seek operation and a positioning operation based on servo information recorded on a data surface on a magnetic disk, wherein a defective track is substituted for a non-positionable cylinder as a defective track. A defect position storing step of storing the position of the defective sector on the defective track as defect position information; and, when passing through a cylinder that cannot be positioned at a low speed seek, the defective sector is determined based on the defect position information. And a seek operation executing step of executing a seek operation by retreating.