JPH0384783A - Evaluation method for mechanism section of magnetic disk device - Google Patents

Abstract

PURPOSE:To evaluate a mechanism section by using a disk easily demagnetized through pressing as a magnetic disk for test and monitoring a head touch in direct relation to an actual fault. CONSTITUTION:A magnetic disk 17 easily demagnetized through pressing is used for a magnetic disk for test and loaded to a mechanism section 11 of a magnetic disk device to reproduce magnetic recording. In this case, when the magnetic disk and a readout write heat are in touch with each other, the part causes demagnetization to reduce the output of a recording signal, then the head touch is caught as the reduction in the reproduction signal. In order to specify the position of the part of head touch, sector information, cylinder information and access state information are inputted to a storage means 22, an information processing means 23 processes each information to display the distribution of the head touch. Since the head touch in direct relation to an erase fault actually is monitored, the mechanism section of the magnetic disk device is evaluated.

Description

[Detailed Description of the Invention] [Summary] Regarding the evaluation method of the mechanical part of a magnetic disk device, we provide a DE evaluation method that can evaluate DE by monitoring head touches that are directly connected to actual erase failures. For the purpose of this, a test magnetic disk that easily demagnetizes when pressurized and has a smooth surface is incorporated into the mechanism, and the decrease in output is recorded by head touch as well as sector information, cylinder information, and The access state information is input into the storage means, and the information processing means processes the information to display the distribution of the head touches.

[Industrial Field of Application] The present invention relates to a method for evaluating a mechanical section of a magnetic disk device.

In magnetic disk drives, in order to achieve higher recording density, it is required to reduce the flying spacing of the head relative to the magnetic disk. For this reason, during DE (disk enclosure) running, there are many head touches where the magnetic disk comes into contact with the head, resulting in head crashes (destruction or damage to the magnetic disk or head) and erase (the magnetic layer of the magnetic disk is reduced due to head touches). This has caused problems such as magnetism and loss of recording.

Therefore, in order to reduce head touches, it is necessary to understand the situation of head touches during DE running and evaluate DE based on this.

[Prior Art] As a conventional method for detecting a head touch between a magnetic disk and a head, there is a method as shown in FIG. 4, for example.

In FIG. 4, 1 is a magnetic disk, 2 is a magnetic head that reads or writes information from the magnetic disk 1, and 3 is a gimbal whose base end is attached to a mounting arm 4 and to which the magnetic head 2 is fixed. , 5 is an actuator that moves the magnetic head 2 via the mounting arm 4 and the gimbal 3.

A piezoelectric element 6 is used to detect a head touch between the magnetic disk 1 and the magnetic head 2, and the piezoelectric element 6 is mounted on the gimbal 3.

An impact when the head 2 touches the magnetic disk 1 is detected by the piezoelectric element 6 and converted into an electrical signal, and the voltage thereof is measured by the voltmeter 7.

Further, the output signal of the piezoelectric element 6 is monitored by an oscilloscope 8, which shows time on the horizontal axis and signal strength on the vertical axis.

9 is a detection signal of the piezoelectric element 6 indicating a head touch.

[Problems to be Solved by the Invention] However, with such conventional head touch detection methods, although it is possible to grasp the number and distribution of head touches, it is difficult to understand the actual number and distribution of head touches. This does not necessarily correspond to the occurrence of an erase failure, and there is a problem in that DE cannot be evaluated based on the detected head touch.

The present invention has been made in view of such conventional problems, and provides a DE evaluation method that can evaluate DE by monitoring head touches that are directly connected to actual erase failures. It is intended to.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In FIG. 1, SL is a step in which a test magnetic disk that easily demagnetizes when pressurized and has a smooth surface is assembled into the mechanism, and S2 is a step in which a magnetic disk for testing, which is easily demagnetized when pressurized, is incorporated into the mechanism, and S2 is sector information along with playback information that detects a decrease in the output of the magnetic disk when the head touches the disk. , a step of inputting cylinder information and access state information into the storage means, and S3 is a step of processing each piece of information by the information processing means and displaying the distribution of the head touches.

[Operation] A magnetic disk that easily demagnetizes when pressurized is incorporated into a mechanical section (DE) of a magnetic disk device as a test magnetic disk, and magnetic recording is reproduced. In this case, when the magnetic disk and the read/write head touch each other, demagnetization occurs at that location and the output of the reproduced signal decreases, so the head touch is interpreted as a decrease in the reproduced signal.

In order to identify the location of such a small reproduction signal, that is, the location of the head touch, sector information, cylinder information, and access state information are input to the storage means.

Then, the information processing means processes each piece of information and displays the distribution of head touches.

In this way, since head touches that are actually directly connected to erase failures are monitored, it is possible to evaluate the mechanical section of the magnetic disk drive.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 2 is a diagram showing an apparatus for carrying out the invention.

In FIG. 2, reference numeral 11 indicates a mechanical section (hereinafter referred to as DE) of the magnetic disk device. An actuator 12 is provided in the DE 11, and the actuator 12 is driven by a voice coil motor 13.

The actuator 12 has a servo head 14 and a read/write head 15 , the servo head 14 reads position information from the magnetic disk 16 and reads the position information from the read/write head 1 .
5 reads the magnetic recording from the test magnetic disk 17.

The test magnetic disk 17 is assembled in order to evaluate DELL, and record data is written in advance. The test magnetic disk 17 is one that easily demagnetizes when pressurized, for example, CO-doped γ-F.
Use one coated with e203 magnetic powder. Here, we conduct a pressure demagnetization test in advance and use a magnet that has been demagnetized to a certain level or higher.

Further, a magnetic disk 17 with a smooth surface is used as the test magnetic disk 17. If there are protrusions or dirt on the disk surface, it may be possible to determine if the cause of the head touch is due to the magnetic disk.
This is because it is not possible to determine whether it is in LL. Note that a normal servo magnetic disk 16 for positioning the disk device is used.

Reference numeral 18 denotes a sector counter. The sector counter 18 outputs sector information indicating where on the circumference of the magnetic disk 17 the head touch point is, and clocks sector pulses input via a control unit (not shown). As a signal,
Clear with index pulse. Reference numeral 19 denotes a cylinder counter. The cylinder counter 19 outputs cylinder information that is position information in the track direction of the head touch, uses a track cross pulse generated when crossing the track as a clock signal, and switches up and down based on theta direction information. .

Also, what state was the actuator 12 in?
That is, access state information is extracted from a control unit (not shown) that drives and controls the actuator 12 in order to know whether it is in an acceleration state, a deceleration state, or an on-track state.

The magnetic recording on the test magnetic disk 17 is converted by the read/write head 15 into an electrical signal that is a reproduction signal. The amplifier 20 amplifies the reproduced signal from the read/write head 15 and outputs it to the comparator 21 .

Here, when the test magnetic disk 17 and the read/write head 15 touch each other, demagnetization occurs at that location, and the output of the reproduced signal becomes smaller.

Therefore, the head touch can be interpreted as a decrease in the reproduction signal (see FIG. 3(B)).

The comparator 21 detects the magnitude of the reproduced signal, classifies the magnitude into, for example, five levels, and outputs the level information to the memory (storage means) 22 using a memory load signal. Therefore, the level of the level information indicates the intensity of the head touch. Level information, sector information, cylinder information, and access state information are input to the memory 22.

Reference numeral 23 denotes a computer as an information processing means for processing the above-mentioned information from the memory 22. The computer 23 calculates the distribution and intensity of the head touch from each of these pieces of information and displays them on the display device 24. The display device 24 displays the distribution and intensity of head touches in a mapped manner.

Next, a method for evaluating DE will be explained.

First, a test magnetic disk 17 that is easily demagnetized when pressurized and has a smooth surface is installed in the DE 11. Magnetic records are written on the magnetic disk 17 in advance.

Next, the reproduction signal, sector information, cylinder information, and access state information of the magnetic disk 17 are taken into the memory 22. The reproduction signal of the magnetic disk 17 is
When the read/write head 15 makes a head touch, demagnetization occurs at that location and the output becomes smaller, so the head touch can be interpreted as a drop in the reproduced signal.

FIG. 3(A) shows a normal case, and FIG. 3(B) shows a case where the reproduced signal has decreased. When the reproduced signal decreases significantly, it can be assumed that the intensity of the head touch was large.

Next, the computer 23 processes the reproduction signal, sector information, cylinder information, and access state information, and displays the distribution and intensity of head touches on the display device 24 in a mapped manner.

In this way, since head touches that are directly linked to actual erase failures are detected, it is possible to evaluate DEll.

[Effects of the Invention] As explained above, according to the present invention, a disk that easily demagnetizes when pressurized is used as a test magnetic disk to monitor head touches that are directly connected to actual failures. Therefore, DE can be evaluated.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a diagram showing an apparatus for carrying out the invention, Figs. 3 (A) and (B) are reproduction signal waveform diagrams, and Fig. 4 is a diagram of the conventional example. It is an explanatory diagram. In the figure, 11... DE (mechanical section of magnetic disk device) 12...
・Actuator, 13... Voice coil motor, 14... Servo head, 5... Read/write head, 6... Magnetic disk, 7... Magnetic disk for test, 8... Sector counter, 9... Cylinder counter, 0... Amplifier, l... Comparator, 2... Memory (storage means), 3... Computer (information processing means), 4... Display device.

Claims (1)

[Claims] A magnetic disk for testing, which easily demagnetizes when pressurized and has a smooth surface, is installed in the mechanism (S1), and the decrease in output is recorded as playback information based on head touch, as well as sector information,
A magnetic disk drive characterized in that cylinder information and access state information are input into a storage means (S2), and the information processing means processes the information to display the head touch distribution (S3). Mechanism evaluation method.