JPS6124069A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To prevent generation of head crash by changing the position of a magnetic head when it is detected that a magnetic disc device does not receive the access of a host device to change the position of a magnetic head. CONSTITUTION:A timer 7, a storage register 8, a comparator circuit 9 and a position setting section 10 provided as a change means for changing the position of a magnetic head 2 when it is detected that no access is received are provided as a detection means for detecting whether or not the magnetic disc device receives the access of the host device. Through the constitution above, when the head 2 receives the access of the host device and not moved while the next comparison is executed after the comparison is executed at the comparator circuit 9, the storage content of a position register 5 is rewritten by an output signal of the comparator circuit 9 independently of the control of the host device. Thus, the magnetic head 2 is moved to a position apart by 100 tracks to prevent adhesion and its accumulation of dust.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in magnetic disk devices widely used as storage devices in information processing systems.

This type of magnetic disk device rotates a recording medium (magnetic disk), which is a rigid disk made of a light alloy layer or a flexible disk made of plastic coated with a magnetic material, at high speed, and records the information on the magnetic disk via a magnetic head. It is a device that writes data or reads data recorded on a magnetic disk d.

2 Normally, a magnetic head is in contact with the magnetic disk surface when the magnetic disk is not rotating, and when the magnetic disk is rotating, it levitates at a small distance from the magnetic disk surface by using hydrodynamic effects. The head positioner is controlled in the radial direction of the magnetic disk by a positioning mechanism (generally referred to as a head positioner), and is configured to select a track for writing or reading.

The flying height of the magnetic head is in units of μm.

Therefore, if the magnetic disk continues to rotate with dust attached to the magnetic head, a head crash may occur, that is, the magnetic head and the magnetic disk drive come into contact, causing damage to the magnetic head or the magnetic disk surface.

2 Normally to prevent such accidents from occurring.

Although the magnetic head and magnetic disk have a sealed dust-proof structure, it is nearly impossible to completely remove dust.

Therefore, the design must be such that even if there is a small amount of dust, 1 to 4 sodokurasociation will not occur.

[Conventional technology]

Fig. 2 is a schematic diagram of the main parts of a conventional magnetic disk device. On the other hand, a drive motor that drives the magnetic head 2, 4 a position detection circuit that detects the current position of the magnetic head 2 using a servo surface provided on one surface of the magnetic disk 1 and the servo head 2s, and 5 a host control device. This is a position register that stores the position of the magnetic head 2 given from (not shown).゛Also, 6 is the magnetic head 2 obtained by the position detection circuit 4.
This amplifier uses the difference between the current position and the position stored in the two-position register 5 as an input signal to order a current to be supplied to the drive motor 3.

With the above configuration, positioning control of the magnetic head 2 is performed with respect to the target position given from the host controller.

[Problem that the invention seeks to solve]

In the magnetic disk device with the above configuration, unless the next target position is given from the host controller.

The magnetic head remains stationary in the same place for a long time.

During this time, the magnetic disk continues to rotate.

If this condition continues for a long time, dust accumulates around the magnetic head, which eventually causes a head crash.

[Means for solving problems]

The present invention provides a detection means for detecting whether or not a magnetic disk device is being accessed by a host device.

The above-mentioned problem is solved by providing a changing means for changing the position of the magnetic head when it is detected that the magnetic head is not being accessed.

[Effect]

In other words, if the detection means determines that the host device will not access the device for a long time, the changing means moves the magnetic head in the radial direction of the magnetic disk, regardless of the control of the host device. prevent dust from accumulating on the

〔Example〕

The gist of the present invention will be specifically explained below with reference to an embodiment shown in FIG.

The figure is a schematic diagram of the configuration of an embodiment of the present invention, and the same reference numerals as in the conventional example in FIG. 2 refer to the same objects.

In addition, 7, 8, and 9 constitute a detection means for detecting whether or not the magnetic disk device is being accessed by a host device, 7 is a timer that sends out a timing signal every predetermined time, for example, every 30 seconds, and 8 is a A holding register that reads the contents of the position register 5 after the comparison by the comparison circuit 9 (to be described later) is completed and holds it until the next comparison is completed. 9 is a holding register that reads the contents of the position register 5 and holds the contents of the position register 5 every time the quimuff sends a timing signal. This is a comparison circuit that compares the stored contents of 8 and 9 and generates an output signal when the two match.

10 also calculates the position of a track that is, for example, 100 trunks away from the magnetic head position indicated by the holding register 8 when the comparator circuit 9 generates the output signal;
A position setting section is provided as a changing means for changing the position of the magnetic head by entering the value in the position register 5.

With the above configuration, if the storage contents of the position register 5 do not change after the comparison is performed in the comparator circuit 9 and until the next comparison is performed, that is, during this period, the magnetic head 2 If the magnetic head 2 is not moved due to access, the stored contents of the 2-position register 5 are rewritten by the output signal of the comparator circuit 9 regardless of the control of the host device, and as a result, the magnetic head 2 moves to a position 100 tracks away. It is moved around and never stays in the same place for a long time.

Therefore, it is possible to prevent dust from accumulating on the magnetic head 2 and prevent head crashes.

〔Effect of the invention〕

As explained above, according to the two aspects of the present invention, head crashes caused by dust adhering to the magnetic head can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a conventional example of a magnetic disk device. In the figure, 1 is a magnetic disk, and 2 is a magnetic head. 5 is a position register, 7 is a timer. Reference numeral 8 indicates a holding register, and reference numeral 9 indicates a comparison circuit 10, a position setting section. Things 1 Mouth ¥ 2 Diagram

Claims (3)

[Claims] (1) In a magnetic disk device that writes or reads data in response to access from a host device, there is a detection means for detecting whether or not the magnetic disk device is being accessed by the host device, and whether or not the magnetic disk device is not being accessed. and changing means for changing the position of the magnetic head when this is detected. (2) The detection means detects whether or not the magnetic disk device is being accessed by the host device based on a change in the position of the magnetic head instructed by the host device. A magnetic disk device according to scope (1). (3) The magnetic disk device according to claim (1), wherein the detection by the detection means or the change by the change means is performed periodically using a timer.