JP2004273061A - Magnetic disk device capable of discarding data on magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To destroy or erase data on a magnetic recording medium by a magnetic disk device itself without needing any special discarding environment. <P>SOLUTION: In the magnetic disk device comprising a magnetic recording medium, a magnetic head, and a controller for controlling a magnetic head and a magnetic recording medium driving motor according to the command of a host computer, data is destroyed from the magnetic recording medium by using the control function of the magnetic disk device itself. An excessive sense current is supplied to an MR head for reproducing data to disable its reading. Data are destroyed from a servo part and a data part by writing predetermined patterns in the servo part and the data part of the magnetic recording medium. By controlling the rotational speed of the magnetic recording medium driving motor to bring the magnetic head into contact with the magnetic recording medium and to slide, the data is destroyed from the magnetic recording medium. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for disposing of data destruction on a magnetic recording medium in a magnetic disk device or a disk array device provided with a large number of magnetic disk devices.
[0002]
[Prior art]
From the viewpoint of personal information protection, there is an increasing need to erase and dispose of data remaining on used magnetic disk drives, but in reality, when disposing of used magnetic disk drives, data is not erased. Generally, it is left as it is.
[0003]
As a conventional technique for erasing data from a magnetic disk device, information is recorded by applying a DC magnetic field in a direction parallel to a recording surface of a magnetic recording medium and moving the magnetic recording medium horizontally with respect to the recording surface. A method has been proposed in which an erased magnetic recording medium can be completely and instantaneously erased by moving in a horizontal magnetic field (Cited Document 1).
[0004]
[Cited Document 1]
JP-A-2002-163801
[0005]
[Problems to be solved by the invention]
However, according to Patent Document 1, in order to erase data, the magnetic recording medium must be removed from the magnetic disk device, and it is necessary to establish an environment in which the surface of the magnetic recording medium is exposed to a DC magnetic field.
[0006]
In order to remove the magnetic recording medium from the magnetic disk device, the magnetic disk device must be handed over to a third person who performs erasure, which poses a problem in terms of protecting personal information. In addition, when the owner of the magnetic disk device performs erasing, it is necessary to construct an environment for performing erasing.
[0007]
An object of the present invention is to perform destruction or erasure of data by the owner of the magnetic disk drive without the intervention of a third party, and to destroy data on a magnetic recording medium that does not require a special environment for disposal. Another object of the present invention is to provide a magnetic disk drive capable of executing erasure.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention mainly employs the following configuration. A magnetic disk comprising: a magnetic recording medium for recording or reproducing data; a magnetic head for recording or reproducing data; and a controller for controlling the magnetic head and a motor for driving the magnetic recording medium in accordance with a command from a host computer. In the device,
A structure in which data on the magnetic recording medium is destroyed by using the control function of the magnetic disk device itself.
[0009]
Further, in the magnetic disk drive, an excessive sense current is applied to an MR head for reproducing data so that the MR head cannot be read.
[0010]
Further, in the magnetic disk device, data in the servo section and the data section is destroyed by writing a predetermined pattern in a servo section that controls positioning on the magnetic recording medium and a data section in which recording data is written. Configuration.
[0011]
Further, in the magnetic disk device, a configuration is provided in which data on the magnetic recording medium is destroyed by controlling the rotation speed of the motor for driving the magnetic recording medium to contact and slide the magnetic head and the magnetic recording medium. I do.
[0012]
Further, in the magnetic disk device, the data portion in which the recording data is written is erased by activating the format function to execute data destruction.
[0013]
By adopting such a configuration, the present invention can execute the destruction or erasure of data on the magnetic recording medium by the magnetic disk device itself without requiring a special environment for disposal.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A magnetic disk device capable of executing data disposal of a magnetic recording medium according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a magnetic disk device relating to a disk disposal technology according to an embodiment of the present invention.
[0015]
The magnetic disk device 10 is connected to the host computer 20 via the host computer interface 30 to control the entire system, a magnetic head control unit 110 to instruct the magnetic head 70 to read / write data, and a magnetic head control unit 110. A motor drive control unit 100 for rotationally driving the recording medium; a magnetic recording medium 60 for storing data; a servo control unit 90 for performing control for moving the magnetic head 70 to a target track 180; And a buffer memory 120 for temporarily storing data used for performing the operation.
[0016]
The controller 40 has a nonvolatile program memory 50 and an internal memory 130. The program memory 50 stores a microprogram having a function of decoding a command from a host, a function of performing a head control in response to the command, and a function of performing a servo control. This microprogram is usually written from the host computer 20 to the program memory 50 in the controller 40 via the buffer memory 120 via the host interface 30. Such a series of operations is generally called download. Using this download function, the microprogram written in the program memory 50 is rewritten.
[0017]
The internal memory 130 is a memory in which set values necessary for the operation of the magnetic disk device 10, for example, set values such as a sense current value of an MR (Magnet Resistance) head 70 are stored. After the power is turned on and the magnetic recording medium 60 reaches a fixed rotation, the controller 40 reads out and sets the MR head setting values and the like written in the internal memory 130.
[0018]
Next, control of read / write to the magnetic recording medium 60 will be specifically described. When a read / write command is issued from the host computer 20 via the host interface 30, the controller 40 determines which track is to be read / written. Then, the servo control unit 90 controls the current according to the movement amount to the target track, and sends the current corresponding to the movement amount to the voice coil 80. By controlling the current to the voice coil 80, the MR head 70 moves to a target track. Next, a read / write current is supplied to the magnetic head 70 via the magnetic head control unit 110.
[0019]
The magnetic head 70 is divided into a write head and a read head. A conventional magnetic head, an inductive head, is used for writing, and a magnetoresistive head (MR head) is used for reading. The magnetoresistive head reproduces a change in the magnetic field generated from the magnetic recording medium 60 when reproducing data on the magnetic recording medium as a change in electric resistance by flowing a sense current to the magnetoresistive element.
[0020]
FIG. 2 is a diagram showing an arrangement relationship between a magnetic recording medium and a magnetic head. According to FIG. 2, the magnetic head 70 is mounted not only on one side but also on the back side of the magnetic recording medium 60, and the magnetic disk device 10 is generally provided with a plurality of magnetic recording media 60.
[0021]
The outline of the magnetic disk device 10 has been described above. Next, a method of data destruction and disposal of a disk according to the embodiment of the present invention will be described.
[0022]
"First Embodiment"
The first embodiment of the present invention is a method of disposing of the magnetic disk device 10 by destroying the MR head used for reproduction in the magnetic head 70. FIG. 3 is a schematic configuration diagram relating to sense current control for controlling a current flowing to the MR head according to the first embodiment. 3, the magnetic head control unit 110 includes a sense current control unit 150 and a sense current drive unit 160. The sense current control unit 150 has a sense current setting table for setting a sense current in the sense current driving unit 160. The sense current driver 160 allows the sense current set in the sense current setting table to flow to the MR head.
[0023]
The MR head converts a change in the leakage magnetic flux on the magnetic recording medium 60 into an electric signal based on the sense current passed through the MR head to obtain a reproduction signal. The sense current value is adjusted to the MR head and the magnetic recording medium 60, and is adjusted for each MR head. Once the optimum value is calculated, the optimum value is stored in the internal memory 130 which is a non-volatile area, and is used while the magnetic disk device 10 continues to be used.
[0024]
In the sense current setting table, the controller 40 reads and sets the optimum sense current value stored in the internal memory 130 corresponding to the MR head. The sense current flowing to the MR head is the current value itself flowing to the MR element 170 of the MR head. Therefore, a large sense current value means that a large amount of current flows through the MR element 170. If a large amount of current flows through the MR element 170, the MR element 170 can be destroyed. Thus, the MR head can be destroyed by the overcurrent to the MR element.
[0025]
The controller 40 sets a value several times the optimum value in the sense current setting table in order to destroy the MR element 170. When the read operation is performed in this manner, a sense overcurrent flows through the MR element 170, causing destruction of the MR element 170 (a phenomenon in which the MR element is burned out and disconnected). As a result, the read operation of the MR head becomes impossible. And can cause head destruction. When a plurality of MR heads are provided (see FIG. 2), the read operation of all MR heads can be disabled by repeating the operation for the number of MR heads. As described above, the first embodiment of the present invention is a data disposal method characterized by destroying the MR element 170 of the MR head.
[0026]
The operation of the first embodiment will be described with reference to the flowchart shown in FIG. When the disposal method according to the first embodiment is selected, the controller 40 first selects a head number (hereinafter, abbreviated as a head number) n (step 250). Here, the head NO. n may be any number. After selecting the head, the controller 40 sets a sense current value several times the optimum sense current in the sense current setting table in the sense current control unit 150 (step 260). Next, a read operation is performed for the purpose of passing a sense overcurrent to the selected MR head (step 270). Since this is only for passing the sense overcurrent to the selected head, the track No. on the recording medium 60 to be read is read. Can be anywhere. During the read operation, the controller 40 repeats the read operation until the controller 40 determines that data cannot be read (step 280) (continues the read operation until the data cannot be read). It is determined whether or not this is the case (step 290). If not, the next head is selected (step 310), and the same operation is repeated until the processing of all the heads is completed.
[0027]
"Second embodiment"
The second embodiment of the present invention is a method of disposing of medium data by destroying data on a track of the magnetic recording medium 60. FIG. 5 is an explanatory diagram showing the data section 190 and the servo section 200 on the track 180 on the magnetic recording medium 60, and also showing the write permission (enable) to the data section and the write disable (disable) to the servo section. .
[0028]
The tracks 180 are concentrically arranged on the magnetic recording medium, and the controller 40 detects the target track 180, instructs the head 70, and writes data for recording. The track 180 is roughly divided into a data section 190 in which data to be recorded is written and a servo section 200 which performs control for detecting a target track 180. When the power of the magnetic disk device 10 is turned on and the magnetic recording medium reaches a predetermined number of revolutions, the controller 40 performs an operation of reading data from the servo unit 200. From the read servo data, the track No. currently positioned is determined. After reading the information in the internal memory 130, a command from the host computer 20 is accepted.
[0029]
Here, as an example, the track No. 100 from the host computer 20 in a state where the track No. A case in which a data write instruction to 200 is performed will be described. The controller 40 determines the track number of the currently positioned track. 100 to the target track No. In order to determine the difference between the moving tracks up to 200 as 100 and position the target track, the servo control unit 90 is instructed to supply a current necessary for the magnetic head 70 to move by 100 tracks to the VCM 80. Upon receiving this command, the servo control unit 90 positions the magnetic head 70 on the target track. The controller 40 starts the write operation after determining that the target track has been positioned.
[0030]
As described above, the servo unit 200 controls the movement from the currently positioned track to the target track. Therefore, if servo information is destroyed by writing meaningless data to the servo unit 200, positioning control cannot be performed. Since the positioning control becomes impossible by destroying the servo unit 200, even if the power is turned on, a command cannot be received from the host computer 20. In addition to rewriting the contents of the servo section, meaningless data can be added to the data section.
[0031]
The disposal method according to the second embodiment is characterized by destroying all the data of one track, which is the data of the servo unit 200 that performs the positioning control and the data unit 190 in which the recording data is written. .
[0032]
Next, a specific disposal method for destroying the servo unit 200 according to the second embodiment will be described. When a write command is issued from the host computer 20 and the positioning of the magnetic head is completed, a write operation starts. However, the controller 40 has a write permission during the servo operation in order to prevent writing data to the servo unit 200 by mistake. The signal (write gate) is set to disable 210 (disable). In other words, the controller 40 sets the write section to permit 220 (enable) in the data section 190 and disable the write gate 210 (disable) in the servo section 200 during data write of one track. As a matter of course, data can be written only when the write gate is enabled 220.
[0033]
The controller 40 normally controls the write gate described above. However, the controller 40 can change this control and execute the setting in which the write gate is enabled 220 in the servo unit 200 as well. After setting to enable 220 the write gate for all data in the data section 190 and the servo section 200 in a certain track, the controller 40 writes the write data (the write data is a fixed data prepared in advance by the controller 40). (For example, all 1 signal pattern). This makes it possible to destroy all data for one track. Here, since the information of the servo unit 200 for performing the positioning control has been destroyed, the positioning control cannot be performed by a normal method.
[0034]
Therefore, a method of moving the magnetic head to the next track in a state where the servo information is destroyed will be described below. FIG. 6 is a schematic diagram showing one track movement of the magnetic head 70. As described above, the track movement of the magnetic head is performed by the servo control unit 90 supplying a current corresponding to the movement amount to the target track to the voice coil 80. After the data destruction of one track is completed, the controller 40 issues a command to the servo control unit 90 that the next track to be subjected to data destruction is (current track + 1). Upon receiving the command from the controller 40, the servo control unit 90 applies a current corresponding to one track to the voice coil 80 to move the magnetic head. That is, the controller 40 shifts the magnetic head by one track by passing a constant current through the VCM. By repeating this operation for all tracks, it is possible to destroy data on all tracks.
[0035]
Next, a method of destructing track data in a plurality of heads will be described with reference to the flowchart of FIG. When this data destruction method is selected, the controller 40 changes the write gate control (step 330) so that the data write operation can be performed over one track. Next, the head NO. 0 is selected (step 350). Here, the head to start is NO. It is set to 0. After selecting the head, the controller 40 sets the track number. A write operation is performed on 0 (step 360). If there are a plurality of heads, the next head is selected (step 410), and the same processing is performed until all the heads are completed (step 370). After executing all the heads, the controller 40 issues a movement command for (current track + 1) to the servo controller 90 to move the head to the next track (step 390). After that, the same process is repeated again. Perform from 0 to all heads. The same processing is repeated until all tracks are completed.
[0036]
"Third embodiment"
Next, data destruction of the servo unit according to the third embodiment of the present invention will be described below. When the power of the magnetic disk device 10 is turned on, the controller 40 issues a rotation start command to the motor drive control unit 100 to rotate the magnetic recording medium 60. The controller 40 waits for the magnetic recording medium 60 to reach a certain rotation and determines that the rotation has reached the certain rotation. Then, the controller 40 executes a reading operation of the internal memory 130 and the like, and waits for an instruction from the host computer 20. At this time, the head 70 and the magnetic recording medium 60 are on standby in a state of floating on the order of submicron.
[0037]
In this standby state, the controller 40 causes the motor drive control unit 100 to change the rotation speed of the disk in order to reduce the flying height of the head 70. By doing so, the head 70 comes into contact with the magnetic recording medium 60, that is, stands by in a sliding state. In this sliding state, the controller 40 issues a movement command for the track + 1 to the servo control unit 90 and outputs the track number. Move to zero. Next, the controller 40 waits for a time corresponding to one rotation of the recording medium in this state. By waiting for one rotation, the head 70 and the magnetic recording medium 60 pass over data of one track while maintaining a sliding state with each other. This makes it possible to mechanically destroy data in the data portion and the serve portion on one track. By repeating this operation for all tracks, data can be destroyed. When the head 70 and the magnetic recording medium 60 are slid, all the heads are slid when a plurality of heads are provided. Therefore, when data destruction for all tracks of one head is completed, data destruction for all heads can be completed. Therefore, even when a plurality of heads are provided, data destruction occurs in the time required for one head to process all tracks. Becomes possible.
[0038]
When the disposal method of the third embodiment is selected, the controller 40 instructs the motor drive control unit 100 to change the rotation of the magnetic recording medium 60. Next, the controller 40 issues a movement command for a track + 1 to the servo control unit 90 to move the head 70. After a lapse of one rotation, the controller 40 issues a movement command for the track + 1 to the servo control unit 90 again and waits for a certain time. The same processing is repeated until all tracks are completed.
[0039]
As described above, in the third embodiment, the recording medium is broken by lowering the rotation speed of the spindle motor for driving the recording medium and sliding the magnetic head and the recording medium in contact. Not only is the recording medium destroyed, but also the magnetic head can be destroyed. In the third embodiment, a current may be applied to the write head to perform the erasing operation at the same time, so that the data may be surely destroyed.
[0040]
"Fourth embodiment"
Next, a data disposal method in the magnetic disk drive according to the fourth embodiment of the present invention will be described. In the above-described first, second, and third embodiments, the method is such that the magnetic disk device 10 is disabled and disposed of. However, in the fourth embodiment, the magnetic disk device 10 is disabled. Instead, it is a data disposal method of the magnetic disk device 10 using a known technique.
[0041]
The controller 40 has a command for erasing data from the magnetic recording medium 60 and at the same time performing a unique format. This format command can erase only the data portion on the magnetic recording medium 60 and perform a prescribed format. Formatting is an operation performed on the data section 190 so that the host computer 20 can actually read / write the magnetic recording medium 60. Even if the format command, which is a known technique, is executed, data in only the data section 190 is processed and erased, so that the magnetic disk device 10 does not become inoperable. When the disposal method of the fourth embodiment is selected, the controller 40 can erase the data of the magnetic recording medium 60 by using a format function which is a known technique, and can perform the destruction disposal of the recorded data.
[0042]
Next, FIG. 8 shows a comparison of the disposal method, the disposal time, and the reusability of the magnetic disk device in the first to fourth embodiments of the present invention. As shown in FIG. 8, in the disposal method of the first embodiment, the disposal time is only several seconds because the reading of the head is only disabled. The disposal method according to the second embodiment requires time to write all tracks, and when there are a plurality of magnetic recording media, the disposal time is equal to the number of magnetic recording media × the disposal time per one.
[0043]
The disposal method of the third embodiment also requires time to write all tracks, but since data destruction is performed on all heads 70 and magnetic recording media 60 at the same time, a plurality of magnetic recording media are required. Even if it has 60, it can be executed in the same time. The disposal method of the fourth embodiment is the same as the disposal method of the second embodiment, and requires time to write all the tracks 180.
[0044]
Regarding whether or not the magnetic disk device 10 can be reused, the first to third embodiments are inoperable and cannot be reused, but the fourth embodiment is reusable.
[0045]
The magnetic disk drive or disk disposal method according to the first to fourth embodiments of the present invention described above can be combined into a download-type disposal-only program. This disposal-only program is different from a program written and executed in the program memory 50 for the operation of the controller 40, and is used by downloading the disposal-only program only when disposing of the magnetic disk device or the disk. . If this disposal-dedicated program is contained in a microprogram that controls the normal operation, there is a risk that the magnetic disk device or the disk may be damaged due to a malfunction. Things.
[0046]
The operation of downloading and executing this disposal program will be briefly described. For example, when the host computer 20 issues an instruction of a disposal method by destroying the MR head to the controller 40, the controller 40 executes the first embodiment described above. Implement a form of disposal method. As described above, the controller 40 implements the first to fourth disposal methods according to the instruction of the host computer 20.
[0047]
Next, a case where the disposal method according to the first to fourth embodiments of the present invention is applied to a disk array device will be described. FIG. 9 is a diagram schematically showing a disk array device connected to the host computer 20. The disk array device is a device in which the reliability is improved by arranging the magnetic disk devices 10 with redundancy, and a plurality of magnetic disk devices 10 are used in one system.
[0048]
FIG. 10 is a flowchart showing an operation procedure when the embodiment of the present invention is applied to the disk array device. In FIG. 10, when it is necessary to dispose of the magnetic disk device 10 used in the disk array device (step 440), first, a program dedicated to disposal is downloaded. The download is performed to all the magnetic disk devices 10 under the system (step 450).
[0049]
Next, a command (steps 460 to 480) according to the disposal method of the magnetic disk device 10 is issued from the host computer 20 to the controller 40 of each magnetic disk device 10. Step 460 is the destruction of the MR element according to the first embodiment, and step 470 is the destruction of the data by executing the write operation on all the data of one track according to the second embodiment. Reference numeral 480 denotes destruction by contact and sliding between the head and the recording medium according to the third embodiment, and step 490 denotes data erasure by initialization in the data section according to the fourth embodiment. At these steps 460, 470, 480, it is determined whether or not each disposal is to be performed, and one of the respective disposals corresponding to those steps is executed as steps 520, 530, 540. If none of the above three dispositions is satisfied, finally, the erasure disposition of the data part data by initialization is executed.
[0050]
Each controller 40 performs processing simultaneously according to the disposal method according to the first to fourth embodiments. After the disposal, the magnetic disk device 10 or the disk is disposed (step 500). As described above, a large number of magnetic disk devices do not have a one-to-one correspondence with the host computer 20. Instead, a dedicated program to be disposed is downloaded to each magnetic disk and all the magnetic disk devices are disposed of in parallel. Can be.
[0051]
As described above, the present invention provides a magnetic disk device having an MR head, a magnetic disk device having servo information added to a data surface on a magnetic recording medium, and a magnetic disk having a controller for receiving a command from a host computer. This is a technique relating to a method for disposing of used disk data, especially for a system such as a disk array device (RAID) in which the magnetic disk device is mounted, and the magnetic disk device itself has a disposal method. Thus, it is possible to dispose of the magnetic disk without requiring the intervention of a third party and without constructing a special environment.
[0052]
In addition, the present invention has a plurality of disposal methods as its embodiments, and according to the purpose of disposal by the owner, the magnetic disk device can be reused or inoperable to prevent reuse. This is to enable selection of disposal.
[0053]
Specifically, after writing a special disposal program different from the program that performs the normal operation in the program area of the magnetic recording medium, the host computer receives a command instructing the disposal method from the host computer and executes the disposal operation according to the disposal method. Is what you do.
[0054]
【The invention's effect】
According to the present invention, when disposing of a magnetic disk device, no special device or equipment for disposing is required, and the magnetic disk device can be implemented without the intervention of a third party. Can be implemented.
[0055]
Further, not only the magnetic disk but also the magnetic disk device can be disabled.
[0056]
Further, when the present invention is applied to a subsystem such as a disk array device having a plurality of magnetic disk devices in one system, each of the magnetic disk devices receiving the disposal command performs disposal simultaneously. Since the processing is performed, the disposal within one system can be performed in the disposal time of one magnetic disk device, and the time can be shortened in performing the disposal.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a magnetic disk drive capable of executing data disposal of a magnetic recording medium according to an embodiment of the present invention.
FIG. 2 is a diagram showing an arrangement relationship between a magnetic recording medium and a magnetic head.
FIG. 3 is a schematic configuration diagram relating to sense current control for controlling a current flowing to an MR head according to the first embodiment.
FIG. 4 is a flowchart showing an operation procedure for destroying the MR head according to the first embodiment.
FIG. 5 shows a data section and a servo section in a track on a magnetic recording medium according to the second embodiment, and shows a write permission (enable) for the data section and a write disable (disable) for the servo section. FIG.
FIG. 6 is a schematic diagram showing one track movement of the magnetic head.
FIG. 7 is a flowchart illustrating a method of destructing data of a track in a plurality of heads according to the second embodiment.
FIG. 8 is a diagram showing a comparison of a disposal method, a disposal time, and reusability of a magnetic disk device in the first to fourth embodiments of the present invention.
FIG. 9 is a diagram schematically showing a disk array device to which the disposal method according to the embodiment of the present invention is applied.
FIG. 10 is a flowchart showing an operation procedure when the embodiment of the present invention is applied to a disk array device.
[Explanation of symbols]
10 Magnetic disk drive
20 Host computer
30 Host interface
40 Controller
50 program memory
60 magnetic recording medium
70 Magnetic Head
80 voice coil
90 Servo control unit
100 Motor drive control unit
110 Magnetic Head Controller
120 buffer memory
130 Internal memory
150 Sense current control unit
160 Sense current driver
170 MR element
180 tracks
190 Data Division
200 Servo unit
210 Recording not allowed
220 Recording permission

Claims (7)

A magnetic disk comprising: a magnetic recording medium for recording or reproducing data; a magnetic head for recording or reproducing data; and a controller for controlling the magnetic head and a motor for driving the magnetic recording medium in accordance with a command from a host computer. In the device,
A magnetic disk drive, wherein destruction of data on the magnetic recording medium is performed by using a control function of the magnetic disk drive itself. In claim 1,
A magnetic disk drive wherein an excessive sense current is applied to an MR head for reproducing data to render the MR head unreadable. In claim 1,
A magnetic disk device for destroying data in the servo section and the data section by writing a predetermined pattern in a servo section that controls positioning on the magnetic recording medium and a data section in which recording data is written. . In claim 1,
A magnetic disk drive, wherein data on the magnetic recording medium is destroyed by controlling the number of rotations of the motor for driving the magnetic recording medium to contact and slide the magnetic head and the magnetic recording medium. In claim 1,
A magnetic disk drive wherein data is written by erasing the data by writing a format function to the data portion to which the recorded data is written, thereby destroying the data. In claim 1,
A magnetic disk drive characterized in that a program dedicated to data disposal required for data disposal of the magnetic recording medium is downloaded from the host computer and data destruction is executed. In claim 6,
For a disk array device having a plurality of magnetic disk devices, a disk characterized in that the program dedicated to data disposal is downloaded to each magnetic disk device and data destruction and disposal are performed on each magnetic disk device simultaneously in parallel. Array device.

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