JP2000123302A - Magnetic disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the disappearance of recorded data by preventing the erroneous recording to an adjacent track due to off-track. SOLUTION: This magnetic disk device is provided with a means for preventing the writing into an adjacent track due to off-track caused by impact, vibration, etc., by comparing an AGC control voltage in the reproduced output of an MR head 2 in a same slider during recording to the data section having no positional information, with a predetermined threshold by a comparator circuit 8.

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 having a magnetic head in which a rotating information recording medium, an inductive head, and an MR head are integrated. It is characterized by a control means for preventing the recorded information of the adjacent track from being lost.

[0002]

2. Description of the Related Art In a conventional magnetic disk drive, there are a data surface servo method and a servo surface servo method as methods for controlling the positioning of a magnetic head. In particular, in the case of a small disk drive having a small number of disks rotating in synchronization with each other, the data surface servo method is often used because of its capacity advantage, but in this method the position information is intermittently recorded on the disk. Since there is a special arrangement, there is no means for knowing the position of the magnetic head between the position information and the next position information, and the position cannot be corrected.

[0003] As described in Japanese Patent Application Laid-Open No. 5-101520, the method of monitoring the envelope of a magnetic head different from the magnetic head during recording involves an offset amount between the recording head and the MR head of each head. If the variation in the following accuracy is large, a sufficient reproduction output cannot be obtained, so that it is often unsuitable for detecting off-track.

Further, thermal asperity of another magnetic head (a phenomenon in which a projection on a disk collides with an MR element and heat is generated, thereby changing the resistance of the MR element and causing a change in reproduction output, hereinafter referred to as TA) ) Or a defect of the disk magnetic film, and the recording may be stopped even if there is no problem with the magnetic head during recording.

[0005]

In the data surface servo system, when an external impact is applied during the passage between the position information and the next position information, the follow-up of the track is deviated by the reaction of the impact. . However, it is not possible to detect that the tracking has been deviated until the next position information is passed, so if the recording operation is being performed at that time, the recording is performed along the locus close to the adjacent track, and the information of the adjacent track is recorded. May be lost.

An object of the present invention is to provide control for suppressing such off-track adjacent writing.

[0007]

In order to achieve the above object, the present invention uses the reproduction output of an MR head in the same slider during data recording and the reproduction output of an inductive head in the same slider during data reproduction. Means for continuously detecting the amount of positional deviation of the following operation even in a section where there is no positional information, and enabling control based on the information.

An application of the above-mentioned means is that, while recording with an inductive head, the reproduction amplitude of a data signal is detected by an MR head in the same slider and the amplitude is not within a predetermined threshold range. Means for interrupting recording are provided.

[0009]

Embodiments of the present invention will be described below in detail. FIG. 1 shows a magnetic head and a magnetic disk of a magnetic disk device used in the present invention. The recording inductive head 1 and the reproducing MR head 2 are configured to be attached to the same head slider 3. With respect to this magnetic head, the magnetic disk 4 rotates so that the MR head 2 passes first. That is, the MR head first passes over the already recorded data of this track, and then the inductive head passes to record on that track.

The circuit configuration shown in the block diagram of FIG. 3 including the magnetic head and the magnetic disk having such a configuration prevents off-track adjacent writing. The recording data 5 is recorded by the inductive head 1. At the same time M
The data is reproduced by the R head 2. The data to be reproduced at this time is data previously recorded according to the passing order of the respective heads. Then, the reproduced data passes through the preamplifier 6 and the AGC circuit 7. Instead of the AGC circuit 7, it is also possible to use a full-wave rectifier circuit and a peak hold circuit.

The AGC circuit 7 described here outputs a control voltage proportional to the magnitude of the input amplitude.
AG that outputs a control voltage that is inversely proportional to the magnitude of the input amplitude
In the C circuit, the same control as the control method described below can be performed. Although the AGC circuit 7 which is normally used for data reproduction is sufficient for the AGC circuit 7, the AGC circuit 7 must be separately provided when it is also used for the following operation during reproduction described below.

The control voltage of AGC circuit 7 is input to a comparison circuit 8 which compares the control voltage with a predetermined threshold value. The threshold value is based on the AGC control voltage at the beginning of writing with the reproduction signal by the MR head, and the lower limit is 80
%, And the upper limit is set to 120% of the same voltage. After that, the AGC control voltage by the MR head is compared with the upper threshold value and the lower threshold value, and the result of recording interruption is performed.

The reference voltage may be selected as a function depending on each head and position. Further, the specific setting of the threshold value is determined according to the limit to the off-track of the disk device and the AGC control voltage. At this time, in a certain sampling interval, a magnetic field is not reversed and a reproduction output may not be obtained due to a recorded data pattern. You need to consider it.

When the magnetic head during recording operates as shown in FIG. 2 between the position information, the AGC control voltage input to the comparison circuit is shown in the block diagram of FIG.
In a state where the signal is not off-track, the signal falls within the threshold range. However, in a state where the signal is off-track, the output gradually decreases and the signal exits the threshold range. At this time, recording is interrupted. Therefore, it is possible to prevent data loss due to off-track writing in an adjacent track.

Further, FIG. 4 is a block diagram in which not only recording is interrupted but also actively used for following control by the same method. The same parts as those in FIG. During the recording by the inductive head 1, the reproduction output of the MR head 2 of the same head slider 3 during the reproduction by the same head slider 3, and during the reproduction by the MR head 2, the AGC control voltage of the inductive head 1 in the same slider passes through the comparison circuit 8, and then the judgment circuit 9. , And the change in the AGC control voltage is used for following control of the magnetic head. The correction amount obtained from the AGC control voltage is added as an auxiliary value to the position amount obtained from the position information.

Although the control voltage may increase or decrease depending on the position of the head even when the head moves in the same direction, the position of the head does not significantly deviate during the following control. Therefore, there is no problem in performing the above control during the following control.
As a result, following can be performed even in a data section having no position information.

The circuits after the preamplifier 6 may be the same for the inductive head 1 and the MR head 2, and can be switched by the switch 11.
Therefore, the circuit scale can be reduced. In FIG. 5, TA in the block diagram of FIG. 3 is input to the comparison circuit 8 when recording is interrupted due to a defect in the disk magnetic film.
3 shows a GC control voltage.

The magnetic disk device is a device that does not perform write & verify. If there is a defect in the TA or disk magnetic film on the magnetic disk, and if recording is performed in such a place, an error occurs during data reproduction. Occurs. Inherent defects on the TA and the disk magnetic film are registered and replaced at the time of shipment from the factory, thereby preventing data reproduction errors.

However, it is not possible to register a late TA or a defect that occurs due to, for example, peeling of the disk magnetic film after shipment from the factory. Data recorded in such a location cannot be restored due to an error during reproduction.

Therefore, the interruption of the recording due to the late TA or the late defect by the method shown in FIG. 3 can achieve the same effect as the write & verify by registering and replacing the relevant portion as the data access prohibition section in the system. Therefore, it is possible to prevent a reproduction error that may occur thereafter. Of course there is no time to verify,
It does not reduce the performance of the device.

Hereinafter, another feature of the present invention will be summarized as follows.

A seek can be performed in the radial direction with respect to a magnetic disk which is a rotating information recording medium.
In a magnetic disk drive for recording and reproducing data by a magnetic head having an R head and an inductive head,
During data recording, the data reproduction output from the MR head in the same slider is detected, and during data reproduction, the data reproduction output from the inductive head in the same slider is detected, so that the head following in the data section having no position information can be followed. A magnetic disk device characterized by performing.

A magnetic disk as a rotating information recording medium can be sought in the radial direction, and M
In a magnetic disk drive for recording and reproducing data by a magnetic head having an R head and an inductive head,
During data recording, the MR head in the same slider detects signal reproduction output in a data section with no position information, and the reproduction output is determined by a predetermined threshold range due to thermal aspirity, disk magnetic film defects, etc. When you go outside,
2. The data reproducing apparatus according to claim 1, wherein in such a data section, an error at the time of reproduction is caused, so that the point is registered as an inaccessible section during data recording, thereby preventing a data reproduction error from occurring. Magnetic disk drive.

[0024]

According to the present invention, even in a data section where position information cannot be obtained, data loss of an adjacent track due to off-track can be prevented. Also, in a data section in which position information cannot be obtained, following control can be performed both during recording and during reproduction. Further, since the reproduction amplitude is monitored during recording, the location of a defect in the TA or the disk magnetic film is registered as an access prohibition section in the system, thereby preventing an error during data reproduction.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a magnetic head and a magnetic disk according to an embodiment of the present invention.

FIG. 2 is an input characteristic diagram to a comparison circuit when the magnetic head goes off-track in the block diagram of FIG. 1;

FIG. 3 is a block diagram for explaining a magnetic head and the like according to the first embodiment of the present invention.

FIG. 4 is a block diagram for explaining a magnetic head and the like according to a second embodiment of the present invention.

FIG. 5 is a diagram showing input characteristics to a comparison circuit in the block diagram of FIG. 3 when there is a defect in TA and a disk magnetic film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inductive head, 2 ... MR head, 3 ... Head slider, 4 ... Magnetic disk, 5 ... Recording data, 6 ... Preamplifier, 7 ... AGC circuit,
8: comparison circuit, 9: judgment circuit, 10: reproduced data,
11 Switch.

Claims (1)

[Claims] 1. A magnetic disk, which is a rotating information recording medium, can be sought in a radial direction.
In a magnetic disk drive for recording and reproducing data by a magnetic head having an R head and an inductive head,
During data recording, the amount of off-track of the magnetic head due to shock, vibration, etc. is determined by detecting a signal reproduction output in a data section having no position information by the MR head in the same slider, and detecting the detected signal with a predetermined threshold value. A data recording operation is stopped by making a comparison with the magnetic disk drive.