JPS62219301A - Demagnetization evaluating device for magnetic disk medium - Google Patents

Abstract

PURPOSE:To easily execute an accelerated evaluation of the demagnetization property of a magnetic disk medium by bringing a sliding head to pressure slide so as to cross a recording track, in a state that information of a recording track is being reproduced, and measuring a variation of a reproducing output caused by the pressure slide. CONSTITUTION:When reproduction is being executed continuously, on the other hand, a sliding head 13 is slid repeatedly so as to cross a data track of a magnetic disk medium 11, and a reproducing output data in this case is made to pass through a recording/reproducing circuit 31 and monitored by a pen recorder 34 through an oscilloscope 32 or an effective voltmeter 33, and also, transmitted to a CPU 36. Subsequently, the demagnetization quantity is detected and evaluated by a drop quantity of the reproducing output in case of having compared with the reproducing output data at the time of non-slide, or the demagnetization property is evaluated by executing a comparative analysis processing. In this way, the demagnetization quantity can be measured and evaluated automatically, and the durability against a true dynamic demagnetization can be easily evaluated without deteriorating a recording/reproducing magnetic head.

Description

[Detailed Description of the Invention] [Summary] The present invention uses an evaluation method to dynamically evaluate the durability of demagnetization caused by sliding of a head on a magnetic disk medium surface used in a magnetic disk device, impact, etc. The device has a structure that includes a sliding head that applies impact and pressure to the magnetic disk medium to be measured, and a recording/reproducing magnetic head for measuring demagnetization, and the surface of the magnetic disk medium on which information is recorded by the recording/reproducing magnetic head. While the information on the recording track is being reproduced, the sliding head is pressed and slid across the recording track, and the change in the reproduction output due to the pressurized sliding is measured. This method allows easy accelerated evaluation of the demagnetization properties of disk media.

[Industrial application field]

The present invention relates to a demagnetization evaluation device for a magnetic disk medium used in a magnetic disk device, etc., and more specifically, it dynamically evaluates the durability of demagnetization phenomena caused by head sliding, fii impact, etc. on the magnetic disk medium surface. This relates to testing equipment.

In recent years, the technology of magnetic disk devices used as large-capacity file devices in computer systems has made remarkable progress, and their storage capacity is on the rise. Along with this, the flying height of the magnetic head with respect to the magnetic disk medium during recording and reproduction also becomes smaller, and the phenomenon of inadvertent sliding contact or collision between the magnetic disk medium and the magnetic head increases.

That is, when the disk medium and the magnetic head collide, if the impact is large, the head crashes and a portion of the recorded portion is destroyed. In addition, if the impact is small, the magnetization of a part of the recording area of the disk medium is attenuated (by the impact or sliding contact), which is a so-called demagnetization phenomenon, and the recorded data signal cannot be reproduced. There are problems in which this becomes weak or impossible.

Therefore, in order to solve these problems, research and development is being carried out on magnetic disk media with excellent shock resistance and demagnetization resistance, but demagnetization of such magnetic disk media causes a decrease in playback output. A means to effectively measure and evaluate is needed.

[Conventional technology]

Conventionally, the method of measuring and evaluating the decrease in reproduction output due to demagnetization of these magnetic disk media has been to use an actual magnetic disk device, for example, by repeatedly performing C3S operation of the magnetic head on the recording track of the magnetic disk medium to cause damage. The demagnetization property is evaluated based on the attenuation change in the reproduced signal output at that time.

[Problem that the invention seeks to solve]

However, in this method, since the recording tracks of the magnetic disk medium are also reproduced by a magnetic head that repeatedly performs CSS operations on the recording tracks, C8
It is clear that the attenuation change in the reproduction signal output of the recording track where the S operation was repeated includes a deterioration phenomenon of the magnetic head due to repeated CSS F'2 operations, or a decrease in reproduction output due to off-track of the magnetic head, etc. There is a disadvantage that demagnetization cannot be evaluated.

Therefore, there is a need for an effective device for dynamically evaluating the demagnetization properties of magnetic disk media.

In view of the current situation, it is an object of the present invention to provide a new demagnetization evaluation device that dynamically accelerates and evaluates the demagnetization property of a magnetic disk medium.

[Means for solving problems]

In order to achieve the above object, the present invention uses a floating type recording/reproducing head for evaluation measurement and a contact type impact and pressure to add damage to the surface of a magnetic disk medium to be evaluated which is rotated by a rotating mechanism. A sliding head is arranged, and while the recording/reproducing magnetic head is reproducing information recorded on the recording track on the surface of the magnetic disk medium, the sliding head is pressurized to cross the recording track. The demagnetization property of the magnetic disk medium is evaluated by sliding the magnetic disk medium and the change in reproduction output caused by the pressurized sliding.

[For production]

In the magnetic disk medium demagnetization evaluation device of the present invention, for the magnetic disk medium to be evaluated mounted on the rotating mechanism,
A dedicated recording/reproducing magnetic head and a damage adding sliding head are separately arranged, so that the recording/reproducing
The amount of demagnetization of the magnetic disk medium to be evaluated can be dynamically and accurately acceleratedly evaluated without deteriorating the reproducing magnetic head.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a magnetic disk medium demagnetization evaluation apparatus according to the present invention.

In the figure, 11 is a magnetic disk medium to be evaluated mounted on a rotating mechanism 22 (not shown), 12 is a recording/reproducing magnetic head, and 13 is a contact type sliding head for applying damage.

The recording/reproducing magnetic head 12 is supported by a first support mechanism 14 having an X stage 15 which is slightly moved in the vertical direction by a fine aA knob 16. It is designed to be able to levitate at great heights.

The contact-type sliding head 13 for applying damage includes an
The second stage has an X stage 20 that moves slightly in the vertical direction by
It is supported by a support mechanism 17, is brought into contact with the surface of the magnetic disk medium 11 rotated by the X stage 20 with a predetermined pressure, and can be repeatedly slid in the radial direction by moving the X stage 18 by the driving means 19. It becomes.

Next, an example of the operation of the demagnetization evaluation apparatus having such a configuration will be described with reference to the schematic configuration diagram of FIG. 2.

First, a data signal for evaluation measurement from, for example, a computer (CPU) 36 is transmitted to the recording/reproducing circuit 31 via an interface bus 37 such as a GP-IB, and the data signal is transmitted to the recording/reproducing circuit 31, which is attached to the rotating mechanism 22 and is being evaluated. A data track is recorded on the surface of the magnetic disk medium 11 by the recording/reproducing magnetic head 12 via the recording/reproducing circuit 31.

Next, the information signal of this data track is reproduced by the recording/reproducing magnetic head 12, and this reproduced output data is recorded via the recording/reproducing circuit 31, for example, via an effective voltmeter 33, to a pen recorder 34, and the CPU 36. While continuing to play, the sliding head 13
is repeatedly slid across the data track of the magnetic disk medium 11, and the reproduced output data at this time is monitored via the recording/reproducing circuit 31, an oscilloscope 32, or an effective voltmeter 33, and a pen recorder 34. ,
The amount of demagnetization is detected by the amount of decrease in the playback output when compared with the playback output data when no sliding is transmitted to the CPU 36,
Alternatively, the CPU 36 performs comparative analysis processing to evaluate the demagnetization property.

In this way, in this embodiment, a series of operations and measurements such as recording/reproducing operations and sliding operations on the 11 sides of the magnetic disk medium to be evaluated are controlled from the CPU 36 via the interface bus 37 such as GP-IB. By controlling the unit 35, it is possible to automatically measure and evaluate the amount of demagnetization, and it is possible to easily evaluate the durability against true dynamic demagnetization without deteriorating the recording/reproducing magnetic head. It becomes possible to do so.

〔Effect of the invention〕

As is clear from the above description, according to the magnetic disk medium demagnetization evaluation apparatus according to the present invention, the damage adding sliding head and the evaluation measurement recording/reproducing head are attached to the surface of the magnetic disk medium to be evaluated. Since the magnetic head can operate simultaneously and in parallel, it is possible to easily and effectively accelerate evaluation of durability against true dynamic demagnetization phenomena, resulting in excellent reliability in demagnetization resistance. This is extremely advantageous as it can be used for research and development of magnetic disk media with good quality.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the magnetic disk medium demagnetization evaluation device according to the present invention, and FIG. 2 shows an example of the operation of the magnetic disk medium demagnetization evaluation device according to the present invention. It is a schematic configuration diagram. 1 and 2, 11 is a magnetic disk medium, 12 is a recording/reproducing magnetic head, 13 is a sliding head, 14 is a first support mechanism, 15.20
is the X stage, 16 is the fine adjustment A knob, 17 is the second support mechanism, 18 is the X stage, 19 is the drive means, and 21 is the fine adjustment B
Knob, 22 is a rotating mechanism, 31 is a recording/reproducing circuit, 32
is an oscilloscope, 33 is an effective voltmeter, 34 is a pen recorder, 35 is a control unit, 36 is a lacquer plate, and 33 is an effective voltmeter.
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Claims (1)

[Claims] A rotating mechanism (22) that rotates a magnetic disk medium (11) to be evaluated, and a first magnetic head (12) that levitably supports a magnetic head (12) that records and reproduces information on the surface of the magnetic disk medium (11). It consists of a support mechanism (14) and a second support mechanism (17) that supports a sliding head that applies impact and pressure to the surface of the magnetic disk medium (11) so as to be able to control the seek in the radial direction while in contact with the surface of the magnetic disk medium (11). The sliding head (13) is slid across the recording track while reproducing information recorded on the recording track on the surface of the magnetic disk medium (11) by the recording/reproducing magnetic head (12). A demagnetization evaluation device for a magnetic disk medium, characterized in that the demagnetization property of the magnetic disk medium (11) is evaluated based on changes in reproduced information due to the sliding.