JPS61239461A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To self extinguish stains or minute flaws sticking on a surface of a magnetic disk and reproduce at an early time and to raise an alarm when they cannot be reproduced by detecting a head touch with a good sensitivity by an AE sensor bonded to a core slider, and lowering the number of rotations of the magnetic disk to seek. CONSTITUTION:A rotation control section 5 retards a rotating speed of a magnetic disk 1 for a predetermined time through a rotating motor 9 by a head touch signal from an AE sensor and lowers an amount of floating of a floating type head 2. During the predetermined time, a seek control section 6 seeks the floating type head 2 in reciprocation radially of the magnetic disk 1 through a linear driving mechanism 4. By this low floating head seek, attachments on the surface of the magnetic disk are removed. After the retardation, when being activated again at an original steady rotating speed, a counter 7 starts to count an output of the AE sensor 3 and when the counted value goes to >=2, stops a rotation through the rotary control section 5 and the linear driving mechanism 4 and drives an alarm circuit 8 to output an alarm signal.

Description

[Detailed Description of the Invention] [Summary] The AE sensor attached to the core slider detects head touches with high sensitivity, and by lowering the rotational speed of the magnetic disk and seeking, dirt and minute scratches on the magnetic disk surface can be removed. It is designed to self-destruct and regenerate at an early stage, and to raise an alarm when it cannot be regenerated.

[Industrial application field]

The present invention relates to a magnetic disk device, and particularly to a structure for preventing head crashes.

[Conventional technology]

Conventional magnetic disk drives use floating magnetic heads, and if dust or foreign matter gets between the head and the recording medium, the head and medium will repeatedly come into contact with each other, eventually leading to a head crash. .

As a means to prevent head crashes, it has been considered to use an AE sensor to detect contact (head touch) between the head and the medium. What is the AE sensor here?
This element is called an acoustic emission elastic wave extraction element, and is an element that sensitively converts minute mechanical vibrations into electrical signals.

Considering the detection sensitivity, it is better to install the AE sensor on the core slider of the floating head, but if head touch is detected using this method, it will not directly lead to a head crash, for example when the head and the medium are started or stopped. This has the drawback that head crashes are detected even during normal contact with the head, making it difficult to determine if a head crash has occurred.

The present invention was created in view of the above-mentioned conventional drawbacks, and
To provide an effective means for determining whether a head touch signal is detected using an E-sensor and whether or not it will lead to a head crash, and to provide an effective means for early removal of the buds of a head crash and self-recovery. With the goal.

[Means to solve the problem]

The present invention, as shown in FIG.
In a magnetic disk drive in which an E sensor 3 is provided on a core slider constituting a part of a floating magnetic head 2 and accessed by a linear drive mechanism 4, the rotational speed of the magnetic disk 1 is determined by the output of the AE sensor 3. a rotation control unit 5 that decelerates the rotation speed by a required time; a seek control unit 6 that causes the floating head 2 to seek reciprocatingly in the radial direction of the magnetic disk 1 during the deceleration period of the disk rotation speed; after the disk has decelerated rotation; , and a counter 7 that counts the output of the AE sensor 3 from the time when the original steady rotation is reached, and when the output value of the carantuff becomes 2 or more, the magnetic disk 1 is controlled via the rotation control unit 5. It is characterized by being provided with an alarm circuit 8 which stops the rotation of the motor and outputs an abnormal signal.

[Effect]

The rotation control unit 5 reduces the rotational speed of the magnetic disk 1 for a required time via the rotation motor 9 in response to a head touch signal from the AE sensor 3, thereby lowering the flying height of the floating head 2. During the required time, the seek control unit 6 causes the floating head 2 to seek back and forth in the radial direction of the magnetic disk 1 via the linear drive mechanism 4. This low-flying Herad seek removes deposits from the magnetic disk surface.

After deceleration, when the counter 7 is restarted at the original steady rotation speed, the counter 7 starts counting the output of the AE sensor 3, and when the counted value becomes 2 or more, the rotation control unit 5 and the linear drive mechanism 4 At the same time, the rotation is stopped and the alarm circuit is driven to output an alarm signal.

〔Example〕

In the block diagram of the present invention shown in FIG. 1, the core slider (
Since the AE sensor 3 attached to the floating head 2) has high detection sensitivity, it is possible to detect sudden intrusion of dust or falling off of dust attached to the magnetic head surface at an early stage.
Further, it is possible to detect at an early stage the attachment of foreign matter to the surface of a magnetic disk (hereinafter simply referred to as medium) or the occurrence of scratches on the surface of the magnetic head or medium.

It should be noted that foreign matter adhering to the surface of the medium is likely to be scraped off by self-vanishing or stretched and rendered harmless until it is not subject to complicated mixing of different types of dust or repeated thermal deformation immediately after the adhesion.

Furthermore, if the scratches generated on the magnetic head or medium surface are small, the scratches are self-vanished by running the magnetic head and medium in contact, as in the case of Contact 5Tart 5Top, and are almost completely regenerated.

Now, when the AE sensor 3 detects a head touch at a predetermined position on the recording surface of the medium, the rotation control unit 5 decelerates the rotational speed of the magnetic disk to a predetermined value by the required time (for example, several tens of seconds) based on the detection signal, and then The rotary motor 9 is controlled to restart data recording/reproduction at the original steady rotation speed. For example, if the steady rotation of 300 rpm is reduced to 1/2, the flying height will be reduced by 30%.

Also, the linear drive mechanism 4 is controlled via the seek control unit 6 to perform reciprocating seek on the recording surface of the medium 1 in the radial direction within the deceleration period of the rotary motor 9, thereby self-vanishing the recording surface of the medium 1. I do. The reason why seek is performed here is that since it can be assumed that the head touch phenomenon occurs at other recording surface positions, it is ideal to seek and vanish the entire recording surface.

Self-vanishing eliminates most of the head touch phenomenon upon restart, but in rare cases the head touch phenomenon may not be resolved and the head touch phenomenon may occur. In this case, the counter 7 starts counting the number of head touch signals from the time of restart, determines that there is a high possibility of progressing to a head crash when there are two or more, and drives the alarm circuit 8 to output an alarm signal. At the same time, the rotation control unit 5 controls the rotation motor 9 so as to stop the rotation of the magnetic disk 1.

If the number of occurrences of the bed touch signal is less than 2 even after the elapse of the required time after restarting, the count of the counter 7 is cleared and the initial state is returned.

FIG. 2 shows an operational flowchart of the present invention as described above.

〔Effect of the invention〕

As described above in detail, the magnetic disk device of the present invention is effective in improving reliability because it is possible to prevent head crashes from occurring and extend the life of the device.

[Brief explanation of drawings]

FIG. 1 shows a block diagram of an embodiment of the invention, and FIG. 2 shows a flowchart explaining the invention in detail.

Claims (1)

[Claims] A magnetic device comprising a core slider of a floating head (2) equipped with an AE sensor (3) for detecting contact with the recording surface of a magnetic disk (1) and minute objects attached to the surface. In the disk device, a rotation control unit (1) that reduces the rotational speed of the magnetic disk (1) by a required time based on the detection output of the AE sensor (3).
5); a seek control unit (6) that causes the floating head (2) to perform reciprocating seek in the radial direction of the magnetic disk (1) during a rotational deceleration period of the magnetic disk (1); a counter () that counts the output of the AE sensor (3) from when the rotation speed of
7), and when the output value of the counter (7) becomes 2 or more, the rotation of the magnetic disk (1) is stopped via the rotation control unit (5), and an abnormality signal is output. A magnetic disk device characterized by being provided with an alarm circuit (8).