JP2001067770A - Magnetic disk device and write control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability in data conservation by detecting the mechanical impact onto a magnetic disk device main body together with the vibration of a required frequency only with one acceleration sensor. SOLUTION: This magnetic disk device is provided with the acceleration sensor 7 detecting the mechanical impact onto the magnetic disk device main body, comparators 11, 12, a flip-flop 15 outputting an impact detection signal to a microprocessor 5 when the level of an analog signal from the acceleration sensor 7 exceeds a first threshold value ±VrefA, the comparators 13, 14 comparing positive/negative both polarity sides of the analog signal from the acceleration sensor 7 with a second threshold value VrefB respectively smaller than the VrefA and generating plural signals, a delay means 16 using plural signals, detecting the vibration of the required frequency and outputting the impact detection signal to the microprocessor 5, an OR 17 and the flip-flop 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic disk drive and a write control method.

[0002]

2. Description of the Related Art A magnetic disk drive provided with a mechanical shock sensor for detecting a mechanical shock having a magnitude exceeding a predetermined threshold has been disclosed (Japanese Patent Laid-Open No. 6-187718).

[0003] A conventional magnetic disk drive has a write-disable circuit that responds to a mechanical shock sensor (shock sensor). The write disable circuit interrupts the write current to the write head of the disk drive when a mechanical shock magnitude greater than a predetermined threshold is sensed. Then, when the mechanical shock is no longer sensed, the data head is repositioned on the original data track, and the incomplete data interrupted by the mechanical shock is rewritten.

That is, a mechanical shock having a magnitude exceeding a predetermined threshold is sensed by a shock sensor, information for identifying data being written at the start of the sensed shock is stored, and a write current to a write head is stored. When the mechanical shock is no longer detected, the data head is repositioned on the original track, and the data interrupted due to the sensed shock is rewritten, so that the disk drive can be operated during the writing process on the magnetic disk. This prevents data on the disk from being contaminated by the mechanical shock applied to the disk.

In a magnetic disk device of this type, that is, a magnetic disk device employing a sector servo system,
Approximately 30 to 100 pieces of servo information are buried in the recording track at a certain time interval per round, and the position error is detected. This means that the actual position error is sampled at a certain time interval.

When a recording head receives a mechanical shock moving to an adjacent track within a continuous servo information interval time during a write operation, adjacent data is contaminated (destructed).

Therefore, such data contamination is prevented by interrupting the write operation by a shock sensor that detects a mechanical shock larger than a predetermined threshold value in advance, and the interrupted write-incomplete data is again transferred to a correct track. We are doing repositioning and rewriting.

In recent years, track density has increased,
Further consideration for vibration is needed.

When the oscillation frequency is sufficiently lower than the embedding time interval of the servo information, that is, the sampling frequency of the position error information, for example, 1/10 or less, the sampled position error information represents the actual position error. However, when the vibration frequency increases, the actual position error cannot be sampled correctly.

As an example, for example, a rotation speed of 5000 rpm,
When servo information is embedded at equal intervals in the recording track, the sampling frequency is 5 KHz,
Although there is no problem up to 00 Hz, a correct position error cannot be detected for a frequency exceeding 500 Hz as the frequency increases.

Further, in the conventional magnetic disk drive, although there is a possibility of detecting the swing in the XY directions on the disk surface, it is not possible to detect the vibration in the Z direction, that is, the floating direction between the disk surface and the head. Impossible.

Since vibration at such a frequency affects data writing, it is necessary to detect the vibration.

However, one shock sensor can only change the level of the threshold value to be detected, and simply lowering the detection threshold value of the shock sensor prohibits a write operation even for a shock or vibration that does not cause a problem. As a result, the performance of the device itself is reduced.

That is, in the case of a conventional magnetic disk drive,
When a recording head receives a mechanical shock that moves to an adjacent track within a continuous servo information interval time during a write operation, the write operation is performed by a shock sensor that detects a mechanical shock larger than a predetermined threshold in advance. Was interrupted to prevent data destruction on adjacent tracks, but since the signal output from the shock sensor was compared using only one threshold to detect a problematic impact,
No consideration is given to the fact that a vibration with an acceleration lower than this threshold causes a similar problem.

[0015]

As described above, in the conventional magnetic disk drive described above, one shock sensor (shock sensor) is provided, and the mechanical shock detected by this sensor is detected at a certain threshold value. However, when vibration of a specific frequency becomes a problem, the only way to detect the vibration is to simply lower the detection threshold of the sensor until the frequency can be detected,
In this case, there is a problem that the write operation is prohibited even for shocks and vibrations that do not cause a problem, that is, over-protection is performed, and the performance of the device itself is reduced.

The present invention has been made in order to solve such a problem, and takes into account the mechanical resonance frequency and the vibration of a desired frequency by one detecting means in consideration of the resonance frequency of the mechanism and the frequency characteristics of the servo control. It is an object of the present invention to provide a magnetic disk drive and a write control method capable of detecting and improving the reliability of data security.

[0017]

In order to achieve the above object, a magnetic disk drive according to the present invention detects a mechanical shock to a magnetic disk drive main body and outputs an analog signal corresponding to the detected shock. Detecting means for outputting information; information writing / reading means for performing information writing and reading operations on a magnetic disk rotationally driven in the magnetic disk device body; and information writing / reading means for writing information If an impact detection signal is input during operation,
At that point, suspend the write operation and retain the information,
A control unit for controlling information to be written to the magnetic disk from the point of interruption; and, when a level of an analog signal output from the detection unit exceeds a first threshold value set in advance, the impact detection signal is transmitted to the magnetic disk. Means for outputting to a control means, and comparator for generating a plurality of signals by comparing both the positive and negative polarities of the analog signal output from the detection means with a second threshold value smaller than the first threshold value. Means for detecting vibration at a desired frequency using a plurality of signals generated by the comparing means and outputting the shock detection signal to the control means.

According to a second aspect of the present invention, a magnetic disk drive detects a mechanical shock to a magnetic disk drive main body,
Detecting means for outputting an analog signal corresponding to the detected impact; information writing / reading means for performing information writing and reading operations on a magnetic disk driven to rotate by the magnetic disk device main body; When an impact detection signal or a vibration detection signal is input during the information writing operation by the read / write means, the writing operation is interrupted at that time, the information is retained, and then the information is written to the magnetic disk from the interruption time. Control means for performing control; and first and second polarities of the analog signal output from the detection means.
Means for outputting a shock detection signal to the control means, and a second side of the analog signal output from the detection means, the second side having a value smaller than the first threshold value.
First to convert to a digital signal by comparing with the threshold of
A second comparator means for comparing the negative side of the analog signal output from the detection means with a negative second threshold value, and converting the analog signal into a digital signal; and Delay means for delaying the digital signal by a predetermined time, and vibration detection signal generation means for generating a vibration detection signal from the digital signal converted by the first comparator means and the digital signal delayed by the delay means. It is characterized by doing. According to a third aspect of the present invention, in the magnetic disk drive according to the second aspect, the vibration detection signal generating means is delayed by the digital signal converted by the first comparator means and the delay means. A logical gate that takes a logical product of the digital signal and outputs a pulse signal; and a signal holding unit that outputs a vibration detection signal to the control unit based on the pulse signal input from the logical gate. .

According to a fourth aspect of the present invention, in the magnetic disk drive of the second aspect, the delay means converts the input digital signal into a signal of several hundred μsec.
The delay circuit is characterized in that it is delayed on the order of up to several msec.

According to a fifth aspect of the present invention, there is provided a light control method,
Detecting a mechanical shock to the magnetic disk drive main body and outputting an analog signal according to the detected shock; detecting a shock when the level of the analog signal exceeds a first threshold; Generating a plurality of signals when the level exceeds a second threshold value smaller than the first threshold value, and detecting vibration at a desired frequency using the generated plurality of signals. A step of, when an impact or vibration is detected during the information writing operation in the magnetic disk device main body, interrupting the writing operation at that time, holding the information, and then writing the information to the magnetic disk from the interruption time And characterized in that:

According to the first and fifth aspects of the present invention, when the mechanical shock to the magnetic disk drive main body is detected by the detecting means, the level of the analog signal output in response to the shock is compared with the first threshold value. While performing normal shock detection, a plurality of signals are generated by comparing the level of the analog signal with the second threshold, and a vibration at a desired frequency is detected using the plurality of signals. The detection means can detect both a strong mechanical impact and a vibration with an acceleration lower than that.

According to the second aspect of the present invention, both the positive and negative polarities of the analog signal output from one detecting means are compared with the first threshold value and output to the control means as an impact detection signal. The positive side of the output analog signal is compared by the first comparator means with a second threshold value smaller than the first threshold value, converted into a digital signal, and the negative side of the analog signal output from the detection means. The second side is compared by a second comparator means with a negative second threshold value and converted into a digital signal, and the digital signal converted by the second comparator means is delayed by a delay means for a predetermined time, and then is delayed. Digital signal and the first
Since the vibration detection signal is generated by the vibration detection signal generation means from the digital signal converted by the comparator means, the impact detection and the vibration detection can be performed by one detection means.

According to the third aspect of the present invention, the vibration detection signal generating means is constituted by a logic gate and a signal holding means such as a flip-flop.

According to the fourth aspect of the present invention, the delay means is constituted by a delay circuit for delaying the digital signal on the order of several hundreds of μsec to several msec. For example, the rotation speed of the magnetic disk is 5000 rpm, and the servo information is recorded on the recording track. In the case where 60 are embedded at equal intervals, the sampling frequency becomes 5 KHz, and vibration up to about 500 Hz is not a problem, but for higher frequencies, for example, vibration at about 800 Hz exceeding 500 Hz, Can also detect that the head has moved to a track adjacent to the recording head.

That is, in the present invention, one detecting means,
In other words, the analog signal detected by the acceleration sensor and output according to the amount of the impact is converted into a digital signal by comparing with a plurality of thresholds, and one digital signal is used for normal impact detection, and the other digital signal is used. Is designed to detect the vibration of the desired frequency by delaying the positive electrode side and taking the logical product with the negative electrode side, so that both strong shock and vibration of the predetermined frequency can be detected, which leads to over-protection However, the reliability of data security can be improved only by adding a simple configuration.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a configuration of a magnetic disk drive according to an embodiment of the present invention.

As shown in FIG. 1, the magnetic disk drive comprises a head 1, a head amplifier 2, read / write means 3, a position detecting means 4, a microprocessor 5, a data buffer 6, an acceleration sensor 7 as a detecting means, It comprises an impact detection IC 10 and the like. The head 1 is attached to a head support mechanism (not shown) so as to move in a radial direction on a magnetic disk surface attached to a spindle motor (not shown), and is written on the magnetic disk during a write operation. Read the servo information and write the information to the corresponding data track. Head amplifier 2
Is for amplifying the read information and outputting it to the read / write means 3. The position detecting means 4 is a read / write means 3
The servo position information is taken out from the microprocessor 5 and sent to the microprocessor 5. The microprocessor 5 performs calculations necessary for positioning control based on the servo position information, and controls the head 1 to follow the data track. The data buffer 6 holds data that has been written in data sector units. The acceleration sensor 7 is an existing sensor for detecting a mechanical shock to the magnetic disk device main body, and is usually mounted on a control board of the magnetic disk device together with the shock detection IC 10 and the microprocessor 5.

The impact detection IC 10 includes a plurality of impact detection comparators 11 and 12, a plurality of vibration detection comparators 13 and 14, an impact flip-flop 15, and a delay unit 1.
6. An IC chip including an OR gate (OR) 17 as a logic gate, a flip-flop 18 for oscillation, and the like. Since the set logic of the flip-flop is negative logic in the impact detection IC 10, the circuit is configured with negative logic (logic having a meaning on the LO side). Therefore, the OR 17 outputs LO when LO and LO are input.

The output of the shock detection comparator 11 is normally set to HI. When the positive side of the analog signal output from the acceleration sensor 7 exceeds a shock detection level + VrefA preset for itself, HI is set to LO.
And the impact flip-flop 15 is set. The output of the shock detection comparator 12 is normally set to HI, and changes from HI to LO when the negative side of the analog signal output from the acceleration sensor 7 exceeds a shock detection level −VrefA preset for itself. Then, the impact flip-flop 15 is set. The output of the vibration detection comparator 13 is normally set to HI, and the positive side of the analog signal output from the acceleration sensor 7 is set to a predetermined vibration detection level + Vr.
HI is changed to LO only during the period exceeding efB, and output to the delay means 16. The output of the shock detection comparator 14 is normally set to HI. When the negative side of the analog signal output from the acceleration sensor 7 exceeds the vibration detection level −VrefB preset for itself, the output HI is set to LO. And input it to OR17. The delay unit 16 is, for example, a shift register 20 configured by cascade-connecting a plurality of flip-flops 21a to 21x, as shown in FIG. 2, and converts the digital signal from the vibration detection comparator 13 to several hundred μsec. The delay is on the order of several msec. OR 17 is delay means 16
The logical sum of the signal input from the controller and the signal input from the vibration detection comparator 14 is obtained, and a one-shot pulse for setting the vibration flip-flop 18 is output when the mutual signal is LO.

The operation of the magnetic disk drive will be described below. This magnetic disk device employs a sector servo system.

First, a normal write operation of the magnetic disk device will be described. At the time of a write operation, the servo information written on the magnetic disk is read by the head 1, sent to the head amplifier 2, amplified, and sent to the read / write means 3.

The position detecting means 4 takes out servo position information from the read / write means 3 and sends it to the microprocessor 5. The microprocessor 5 performs calculations necessary for positioning control based on the servo position information, and controls the head 1 to follow the data track.

After the head 1 follows the data track, the microprocessor 5 gives permission of the write operation to the target sector to the read / write means 3 and the data buffer 6, and records the data on the head 1 through the head amplifier 2. A current is passed, and information is written to the data tracks of the magnetic disk.

Next, the shock detection operation and the vibration detection operation will be described with reference to FIGS. When a shock is applied to the magnetic disk device main body and a mechanical shock is detected by the acceleration sensor 7, as shown in FIG.
An analog signal (signal swinging to both positive and negative poles) corresponding to the impact is generated, and a plurality of impact detection comparators 11 and 1 are generated.
2. Input to the vibration detection comparators 13 and 14, respectively.

The positive side of the analog signal is compared by the impact detection comparator 11, and the negative side is compared by the impact detection comparator 12.

Then, the impact detection comparators 11 and 12
Preset threshold level (first
Above the impact detection level ± VrefA), for example, ± 2G,
The outputs of the impact detection comparators 11 and 12, that is, the digital signal HI changes to LO, and the impact flip-flop 15 is set.

For example, as shown in FIG. 3 (b), the output (digital signal HI) of the analog signal output from the acceleration sensor 7 is output only during a period in which it exceeds the shock detection level + VrefA of the shock detection comparator 11, as shown in FIG. Is LO
And the impact flip-flop 15 is set when the output changes.

When the impact flip-flop 15 is set, its output changes from LO to HI.

The microprocessor 5 causes the read / write means 3 to immediately interrupt the write operation when the signal from the impact flip-flop 15 is switched to HI, determines the interrupted data sector address, and
Causes interrupted data to be retained. On the other hand, as shown in FIG. 4A, an analog signal which is an output of the acceleration sensor 7 is:
It is also input to the vibration detection comparators 13 and 14.

If the level on the negative side of the analog signal input from the acceleration sensor 7 exceeds a threshold level (second vibration detection level -VrefB) preset in the vibration detection comparator 14, for example, -1G level, As shown in FIG. 4B, the output of the vibration detection comparator 14, that is, the HI of the digital signal changes to LO only during the period exceeding -VrefB, and becomes a rectangular wave to become O.
Input to R17. Further, the level of the analog signal output from the acceleration sensor 7 on the positive electrode side is a threshold level (second vibration detection level ± VrefB) preset in the vibration detection comparator 13, for example, + 1G
Exceeds the level of Vre, as shown in FIG.
Only during the period exceeding fB, the output of the vibration detection comparator 13, that is, the HI of the digital signal changes to LO, and is input to the delay means 16 as a rectangular wave. The delay element 16 delays the input rectangular wave by a predetermined delay time length τ and outputs it to the OR 17 as shown in FIG. 4D, so that the OR 17 outputs the output signal of the vibration detection comparator 14 and the delay signal. The logical sum (logical product on positive logic) with the output signal of the vibration detection comparator 13 delayed by the predetermined delay time length τ by the element 16 is obtained.

Then, as shown in FIG. 4E, when both output signals become LO, a single pulse of LO is output from the OR 17 to the oscillation flip-flop 18. The oscillation flip-flop 18 is set, and the output of the oscillation flip-flop 18 is switched from LO to HI and held as shown in FIG.

When the signal from the oscillation flip-flop 18 is switched to HI, the microprocessor 5 immediately causes the read / write means 3 to interrupt the write operation, determines the interrupted data sector address, and interrupts the data buffer 6. Retain data.

Since the two vibration detection comparators 13 and 14 respectively detect peaks of opposite polarities, if the delay time length of the output signal from the vibration detection comparator 13 is τ, the detectable frequency is １ ／ τ or more. Becomes

The frequency to be detected is determined by the impact detection comparator 11, the frequency characteristic of the servo control, etc.
A frequency that causes a problem with a threshold lower than the acceleration detected at 12 is set. For example, 800 Hz or the like. For example, 800
In order to detect a vibration of Hz, a delay time length τ of about 625 μsec is required. Such several hundred μsec to several m
In order to delay the digital signal on the order of seconds, it is preferable to operate the shift register 20 shown in FIG. 2 with a clock of several hundred KHz.

As a result, destruction of data on an adjacent track due to interruption of the write operation is prevented. After holding the data, the microprocessor 5 positions the rest of the data that has not been completely written to the target track again, starting from the interrupted data in the data buffer 6, and writes it.

As described above, according to the magnetic disk drive of this embodiment, the analog signal detected and output by one acceleration sensor 7 is output to the plurality of comparators 1.
1, 12, 13, and 14, among which the shock detection comparators 11 and 12 detect a normal shock at the first threshold value ± VrefA, and the vibration detection comparator 1
In steps 3 and 14, waveforms of opposite polarities are compared with a second threshold value VrefB in order to detect vibration of a desired frequency, and one of a plurality of generated digital signals is delayed. Since a vibration at a desired frequency is detected by taking a logical sum (logical product on positive logic), even if only one acceleration sensor 7 is used, a strong mechanical shock which is a problem and a lower mechanical shock are required. The vibration of the acceleration can be detected together, and the reliability of data maintenance can be improved without overprotecting the magnetic disk device main body and only by adding a simple circuit element.

In this magnetic disk drive, similar elements such as comparators 13 and 14, flip-flops 18, and OR 17 are mounted on an IC chip on which conventional impact detection comparators 11 and 12 and flip-flop 15 are formed. Since only addition is required, it can be made into one chip as in the conventional case.

In the above embodiment, several hundred μsec.
To delay a digital signal in the order of several milliseconds,
Although the shift register 20 is used as the delay unit, the delay unit may be configured by an R or C circuit using a resistor, a capacitor, or the like.

[0049]

As described above, according to the first and fifth aspects of the present invention, when the mechanical shock to the magnetic disk drive main body is detected by the detecting means, the level of the analog signal output in response to the shock is detected. And a first threshold value to perform normal shock detection, while comparing the level of the analog signal with the second threshold value to generate a plurality of signals, and using the plurality of signals to generate a desired frequency. Is detected, a single detecting means can detect both a strong mechanical impact and a vibration having a lower acceleration.

According to the second aspect of the present invention, both the positive and negative polarities of the analog signal output from one detecting means are compared with the first threshold value, and the analog signal is output to the control means as an impact detection signal. The positive side of the analog signal output from the means is compared by the first comparator means with a second threshold value smaller than the first threshold value, converted into a digital signal, and the analog signal output from the detection means. The negative side is compared with a second negative threshold value by a second comparator means and converted into a digital signal. The digital signal converted by the second comparator means is delayed by a predetermined time by a delay means. Since a vibration detection signal is generated by the vibration detection signal generation means from the delayed digital signal and the digital signal converted by the first comparator means, one detection So that it is the impact detection and vibration detection in stage.

According to the third aspect of the present invention, the vibration detection signal generating means is constituted by a logic gate and a signal holding means such as a flip-flop, thereby realizing an inexpensive and simple configuration.

According to the fourth aspect of the invention, the delay means is constituted by a delay circuit for delaying the digital signal on the order of several hundred μsec to several msec, so that, for example, the rotation speed of the magnetic disk is 5000 rpm and the servo information is When 60 tracks are embedded at equal intervals in a recording track,
The sampling frequency becomes 5 KHz, and vibration up to about 500 Hz is not a problem, but it is possible to detect that the recording head has moved to an adjacent track even with vibration at a higher frequency, for example, about 800 Hz exceeding 500 Hz.

As a result, a single detecting means can detect both the mechanical shock and the vibration having a lower acceleration than the mechanical shock, thereby improving the reliability of data preservation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a magnetic disk drive according to one embodiment of the present invention.

FIG. 2 is a diagram showing a shift register as an example of delay means in the magnetic disk device.

FIG. 3 is a diagram showing signals when a normal impact is detected in the magnetic disk device.

FIG. 4 is a diagram showing signals in a case where vibration of a desired frequency is detected in the magnetic disk device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Head, 2 ... Head amplifier, 3 ... Read / write means, 4 ... Position detection means, 5 ... Microprocessor, 6 ...
Data buffer, 7: acceleration sensor, 10: shock detection IC, 11, 12: shock detection comparator, 13, 1
4 ... Comparator for vibration detection, 15 ... Flip-flop for shock, 16 ... Delay means, 17 ... OR gate (OR),
18. Vibration flip-flop.

Claims (5)

[Claims] A detecting means for detecting a mechanical shock to the magnetic disk device main body and outputting an analog signal in accordance with the detected shock; and writing information to a magnetic disk rotationally driven in the magnetic disk device main body. An information writing / reading unit for performing an operation and a reading operation; and when the information writing / reading unit receives an impact detection signal during the information writing operation, the writing operation is interrupted at that time to hold the information. And control means for controlling the writing of information on the magnetic disk from the point of interruption, and when the level of the analog signal output from the detection means exceeds a first threshold value set in advance, the shock detection signal Means for outputting to the control means, and the positive and negative polarities of the analog signal output from the detecting means each having a value smaller than the first threshold value. A comparator means for generating a plurality of signals by comparing with a threshold value of 2; a vibration of a desired frequency is detected using the plurality of signals generated by the comparator means; and the shock detection signal is transmitted to the control means. And a means for outputting. A detecting means for detecting a mechanical shock to the magnetic disk device main body and outputting an analog signal corresponding to the detected shock; and an information writing operation on a magnetic disk rotationally driven by the magnetic disk device main body. And an information writing / reading unit for performing a reading operation and a shock detecting signal or a vibration detecting signal during the information writing operation of the information writing / reading unit. After holding, control means for controlling the writing of information to the magnetic disk from the point of interruption, and the positive and negative polarities of the analog signal output from the detecting means are compared with a first threshold value, and the shock detection signal is output. Means for outputting to the control means; and a second threshold having a value smaller than the first threshold for the positive side of the analog signal output from the detection means. And a second comparator for comparing the negative side of the analog signal output from the detecting means with a negative second threshold value and converting the analog signal to a digital signal. Means, delay means for delaying the digital signal converted by the second comparator means for a predetermined time, and vibration detection from the digital signal converted by the first comparator means and the digital signal delayed by the delay means A magnetic disk drive comprising: a vibration detection signal generating means for generating a signal. 3. The magnetic disk drive according to claim 2, wherein the vibration detection signal generating means calculates a logical product of the digital signal converted by the first comparator means and the digital signal delayed by the delay means. A magnetic disk device comprising: a logic gate for outputting a pulse signal; and a signal holding unit for outputting a vibration detection signal to the control unit in accordance with the pulse signal input from the logic gate. 4. The magnetic disk drive according to claim 2, wherein the delay means converts the input digital signal from several hundred μsec to several msec.
A magnetic disk device comprising a delay circuit for delaying in the order of c. 5. A step of detecting a mechanical shock to the magnetic disk device main body and outputting an analog signal in accordance with the detected shock, and when the level of the analog signal exceeds a first threshold value,
Detecting an impact; generating a plurality of signals when the level of the analog signal exceeds a second threshold value smaller than the first threshold value; and using the plurality of generated signals. A step of detecting vibration at a desired frequency; and if an impact or vibration is detected during the information writing operation in the magnetic disk device main body, the writing operation is interrupted at that time, the information is held, and then the interruption point is reached. And writing information to the magnetic disk.