JP3942932B2 - Magnetic disk and magnetic disk device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk and a magnetic disk device used as an external storage device such as a computer. In particular, the reliability of the magnetic head can be improved by preventing floating of the magnetic head, and the use efficiency of the magnetic disk can be improved. The present invention relates to a magnetic disk and a magnetic disk device that can be increased.
[0002]
[Prior art]
A conventional magnetic disk device is used as a mass storage device such as a computer, and uses a disk-shaped magnetic disk as a recording medium. FIG. 5A shows the configuration of the main part of a conventional magnetic disk device. In the figure, a magnetic disk 1 is a disk-shaped recording medium for magnetically recording data, and is rotated at high speed in the direction of the arrow shown in the figure.
[0003]
The magnetic head 2 reads / writes data from / to the magnetic disk 1 while floating several tens of nanometers by buoyancy generated between the magnetic head 1 and the magnetic disk 1 rotating at high speed. At the time of this read / write, the magnetic head 2 is movable in a range from the outer periphery to the inner periphery of the magnetic disk 1 along a locus that draws an arc, and is moved to a predetermined position.
[0004]
Here, in the magnetic disk 1, data is written in the entire area (shaded area) from the outer periphery to the inner periphery. Accordingly, the moving range of the magnetic head 2 is the maximum value in the radial direction from the outer periphery to the inner periphery.
[0005]
Here, the recording density of the magnetic disk in the magnetic disk device is increasing year by year due to technological progress. Therefore, there is a large difference in recording density between the magnetic disk device manufactured several years ago and the latest magnetic disk device.
[0006]
For example, when the recording density of the magnetic disk is 5 times larger between the old and new magnetic disk devices, the new magnetic disk device is different from the old magnetic disk device having a storage capacity of 1 gigabyte on one magnetic disk. Will have a storage capacity of 5 gigabytes, which is five times larger than that of a single magnetic disk (however, the same area as an old magnetic disk).
[0007]
Conventionally, when performing trouble recovery, upgrading from an old magnetic disk device to a new magnetic disk device, etc., the magnetic disk 1 shown in FIG. Data transfer is performed in which data recorded at (recording density: low) is recorded on the magnetic disk 3 (recording density: high) shown in FIG. 5B in the new magnetic disk device.
[0008]
In this case, the recording density of the new magnetic disk 3 shown in FIG. 5B is higher than the recording density of the old magnetic disk 1 shown in FIG. Data is recorded in the outer peripheral area 3 a which is the outer peripheral area of the magnetic disk 3. Therefore, in the magnetic disk 3, the inner peripheral area 3b is unused.
[0009]
Here, the magnetic head 4 is moved only within a range covering the outer peripheral region 3a. Therefore, in the case of the magnetic head 4, the movement range is narrower than that of the magnetic head 2 shown in FIG.
[0010]
[Problems to be solved by the invention]
As described above, conventionally, when data recorded on a magnetic disk having a low recording density is recorded on a magnetic disk having a high recording density, the movement of the magnetic head is limited to a narrow range.
[0011]
In this case, since the magnetic head floats at a fixed point (narrow range), the floating point is in a fixed point, so that dust or the like tends to adhere to the magnetic head, and the reliability may be lowered due to the occurrence of a head crash or the like. There was a problem.
[0012]
Conventionally, a large area called the inner peripheral area 3b shown in FIG. 5 (b) is unused, so that there is a problem that the utilization efficiency of the magnetic disk is low.
[0013]
The present invention has been made in view of the above, and provides a magnetic disk and a magnetic disk device that can improve reliability by preventing a fixed-point floating of a magnetic head and can improve the utilization efficiency of a magnetic disk. For the purpose.
[0014]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides:A magnetic disk that is a disk-shaped recording medium having a predetermined recording area, and when providing a permission area that allows a user to access a part of the recording area, the radius ranges from the outer periphery to the inner periphery. The permission areas are arranged in a distributed manner with respect to each skipped divided area in each divided area sandwiched by different concentric circles.
[0015]
  According to this invention,When providing a permission area that allows the user access to a part of the recording area, for each divided area in the divided area sandwiched by concentric circles having different radii from the outer periphery to the inner periphery, Since the permitted areas are distributed and arranged, even if a large number of unused areas are generated on the disk medium, the permitted areas can be distributed over the entire disk medium. The reliability can be improved by preventing the problem of floating on the fixed point.
[0016]
  The present invention also provides:The divided area includes an outer peripheral area, an intermediate area, and an inner peripheral area, and the permission areas are distributed with respect to the outer peripheral area and the inner peripheral area.
[0017]
  According to this invention,The divided areas are composed of an outer peripheral area, an intermediate area, and an inner peripheral area, and the permission areas are distributed and arranged with respect to the outer peripheral area and the inner peripheral area. It is possible to disperse the permitted areas and increase the reliability of the magnetic head by increasing the moving distance of the magnetic head and preventing the problem of floating at a fixed point.
[0018]
  The present invention also provides:It is divided as a region sandwiched by concentric circles having different radii from the outer periphery to the inner periphery, and is divided in the circumferential direction.
[0019]
  According to this invention,The segmented area is divided as a region sandwiched by concentric circles with different radii from the outer periphery to the inner periphery, and is divided in the circumferential direction, so it is permitted from the outer periphery to the inner periphery and the same circumference. Since the regions can be dispersed, the reliability can be improved by preventing the problem of floating of the fixed point of the magnetic head.
[0020]
  The present invention also provides:A magnetic disk device having a magnetic disk, which is a disk-shaped recording medium having a predetermined recording area, where a permission area for allowing a user access to a part of the recording area is provided from the outer periphery. A magnetic disk in which the permission areas are distributed in each divided area sandwiched by concentric circles having different radii around the circumference, and a magnetic disk that reads / writes data to / from the divided areas And a head.
[0021]
  According to this invention,When providing a permission area that allows the user access to a part of the recording area, for each divided area of one skip in each divided area sandwiched by concentric circles with different radii from the outer periphery to the inner periphery, Since it is provided with a magnetic disk in which permitted areas are distributed and a magnetic head that reads / writes data to / from the divided areas, even if a large number of unused areas occur on the disk medium, Since the permitted area can be distributed over the entire disk medium, the reliability can be improved by preventing the problem of floating of the fixed point of the magnetic head.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a magnetic disk and a magnetic disk apparatus according to the present invention will be described below in detail with reference to the drawings.
[0023]
FIG. 1 is a block diagram showing the configuration of an embodiment according to the present invention. The magnetic disk device 10 shown in the figure is used as a storage device such as a computer. In the magnetic disk device 10, the magnetic disk 11 is a disk-shaped recording medium for magnetically recording data.
[0024]
An SPM (spindle motor) 12 rotates the magnetic disk 11 at a high speed in the direction of the arrow shown in FIG. The SPM drive unit 13 drives the SPM 12 with a drive current based on control of an MPU (Micro Processing Unit) 21 described later. The magnetic head 14 is composed of a head core having a very narrow gap and a coil wound around the head core (both not shown), and is supported at the tip of an arm-shaped carriage 15.
[0025]
The magnetic head 14 reads / writes data from / to the magnetic disk 11 while floating several tens of nanometers by buoyancy generated between the magnetic head 14 and the magnetic disk 11 rotating at high speed.
[0026]
Specifically, the magnetic head 14 writes data to the magnetic disk 11 with a magnetic field generated by a recording current supplied to the coil during writing, while magnetically recording the data recorded on the magnetic disk 11. It is detected as a reproduction voltage (read signal).
[0027]
A VCM (voice coil motor) 16 rotates the carriage 15 to move the magnetic head 14 to a target position along a trajectory that draws an arc in the range from the outer periphery to the inner periphery of the magnetic disk 11. The VCM drive unit 17 drives the VCM 16 with a drive current based on the control of the MPU 21.
[0028]
A head IC (Integrated Circuit) 18 includes a write amplifier and a read amplifier (both not shown), and is disposed in the vicinity of the magnetic head 14. The write amplifier has a function of switching the polarity of a recording current to be supplied to the magnetic head 14 in accordance with write data supplied from a host 30 described later. On the other hand, the read amplifier amplifies the reproduction voltage (read signal) detected by the magnetic head 14 and supplies it to the read channel 19.
[0029]
The read channel 19 is a modulation circuit for writing write data to the magnetic disk 11, a parallel / serial conversion circuit for converting parallel write data to serial data, and a demodulation circuit for reading read data from the magnetic disk 11. Etc.
[0030]
The read channel 19 includes a serial / parallel conversion circuit that converts serial read data into parallel data, a synthesizer circuit that generates a timing signal by multiplying the frequency of an oscillation circuit using a crystal resonator, and the like. ing.
[0031]
The servo demodulator 20 demodulates the positioning servo pattern recorded on the magnetic disk 11 by peak hold or integration. The MPU 21 executes servo control, read / write control related to data read / write with respect to the magnetic disk 11, and the like.
[0032]
In servo control, the MPU 21 recognizes the servo pattern demodulated by the servo demodulator 20 and controls the drive currents of the SPM drive unit 13 and the VCM drive unit 17, thereby positioning the magnetic head 14 on the magnetic disk 11. I do.
[0033]
A RAM (Random Access Memory) 22 temporarily stores write data supplied from the host 30, read data read from the magnetic disk 11, and the like. A ROM (Read Only Memory) 23 stores a control program executed by the MPU 21.
[0034]
The communication unit 24 is connected to the host 30 via a SCSI (Small Computer System Interface) bus (not shown), and transmits and receives various commands (read command, write command, etc.), write data, read data, and the like. The host 30 has a function of transmitting various commands and write data to the communication unit 24 and a function of receiving read data read from the magnetic disk 11 from the communication unit 24.
[0035]
FIG. 2 is a plan view showing the configuration of the magnetic disk 11 shown in FIG. The magnetic disk 11 shown in the figure corresponds to the magnetic disk 3 shown in FIG. 5B, and has a higher recording density than the magnetic disk 1 (see FIG. 5A).
[0036]
The magnetic disk 11 is divided into a plurality of concentric circles, and a data recording area 11 from which data is read / written.₁(Shaded area), backup data recording area 11 in which backup data is read / written₂Data recording area 11_Three(Shaded area), backup data recording area 11_FourData recording area 11_Five(Shaded area), backup data recording area 11₆ have.
[0037]
That is, in the magnetic disk 11, the data recording area and the backup data recording area are alternately set concentrically. Data recording area 11₁, 11_ThreeAnd 11_Five Are all given addresses from the outer periphery toward the inner periphery.
[0038]
Further, in the magnetic disk 11, a backup data recording area 11 is provided.₂, 11_FourAnd 11₆ Are all given addresses from the outer periphery toward the inner periphery. These backup data recording areas 11₂, 11_FourAnd 11₆ In the data recording area 11₁, 11_ThreeAnd 11_Five The same data as the data recorded in is written as backup data.
[0039]
Here, a description will be given of a case where data recorded on the magnetic disk 1 shown in FIG. 5A is recorded on the magnetic disk 11 shown in FIG. In this case, data and write commands recorded on the magnetic disk 1 are transferred from the host 30 shown in FIG. As a result, the MPU 21 passes the data to be written to the magnetic head 14 via the read channel 19 and the head IC 18.
[0040]
In addition, the MPU 21 performs servo control by controlling the SPM drive unit 13 and the VCM drive unit 17. As a result, the magnetic head 14 shown in FIG.₁On track, and moves from the outer periphery to the inner periphery as a whole, and the data recording area 11₁ , Backup data recording area 11₂ , ..., backup data recording area 11₆ Write data (backup data) in this order.
[0041]
When reading data from the magnetic disk 11, the outer data recording area 11₁ To the inner data recording area 11_Five Since the data has been written until this time, the magnetic head 14 theoretically reads the data while moving in a wide range from the outer periphery to the inner periphery.
[0042]
The data recording area 11₁, 11_ThreeAnd 11_Five When the data written to the disk is destroyed, the magnetic head 14 causes the backup data recording area 11 to be destroyed.₂, 11_FourAnd 11₆ Backup data is read from.
[0043]
The backup data recording area 11 shown in FIG.₂  , 11_FourAnd 11₆ In the above example, the backup data is written. However, from the viewpoint of preventing only the fixed point floating, the backup data may not be written and may be used as an unused area.
[0044]
In one embodiment, the magnetic disk 40 having the division method shown in FIG. 3 may be used instead of the magnetic disk 11 shown in FIG. The magnetic disk 40 is divided into three concentric circles. Specifically, in the magnetic disk 40, the outer periphery data recording area 40₁ Is an area which is set in the outer periphery and data is read / written.
[0045]
Inner circumference data recording area 40₂ Is an area which is set in the inner periphery and where data is read / written. These outer periphery data recording areas 40₁And inner data recording area 40₂Are given addresses from the outer periphery to the inner periphery.
[0046]
Backup data recording area 40_ThreeIs the outer circumference data recording area 40₁And inner circumference data recording area 40₂This is an area where backup data is read / written. The backup data recording area 40_Three Are given addresses from the outer periphery to the inner periphery.
[0047]
Here, as in the case described above, when data recorded on the magnetic disk 1 shown in FIG. 5A is recorded on the magnetic disk 40 shown in FIG. 3, the magnetic head 14 shown in FIG. Peripheral data recording area 40 of the magnetic disk 40₁On track, and moves from the outer circumference to the inner circumference as a whole, and the outer circumference data recording area 40₁ , Inner circumference data recording area 40₂ And backup data recording area 40_Three Write data (backup data) in this order.
[0048]
When data is read from the magnetic disk 40, the outer periphery data recording area 40 is read.₁ And inner data recording area 40₂Therefore, the magnetic head 14 theoretically reads the data while moving in a wide range from the outer periphery to the inner periphery.
[0049]
In the above description, the backup data recording area 40 shown in FIG._Three In the above example, the backup data is written. However, from the viewpoint of preventing only the fixed point floating, the backup data may not be written and may be used as an unused area.
[0050]
In one embodiment, the magnetic disk 50 of the division method shown in FIG. 4 may be used instead of the magnetic disk 11 shown in FIG. The magnetic disk 50 is divided into a plurality of concentric circles and divided into a plurality in the circumferential direction. Specifically, in the magnetic disk 50, the concentric region 50 from the outer periphery toward the inner periphery.₁ , 50₂ ..., 50₇ Is set.
[0051]
Further, the concentric region 50₁ In the data recording area 50, data is read / written in the circumferential direction._1aBackup data recording area 50 where backup data is read / written_1b The data recording area and the backup data recording area are alternately set.
[0052]
Similarly, the concentric region 50₂ In the backup data recording area 50 in the circumferential direction_2aData recording area 50_2b The data recording area and the backup data recording area are alternately set in units of one sector.
[0053]
Further, the concentric region 50₇ In the data recording area 50 in the circumferential direction._7a, Backup data recording area 50_7b The data recording area and the backup data recording area are alternately set. Thus, in the magnetic disk 50, the data recording area and the backup data recording area are set alternately in the radial direction and the circumferential direction.
[0054]
Data recording area 50_1a ,... Are all assigned addresses from the outer periphery toward the inner periphery. Similarly, the backup data recording area 50_1b ... Are also given addresses as a whole from the outer periphery toward the inner periphery.
[0055]
In the same manner as described above, when data recorded on the magnetic disk 1 shown in FIG. 5A is recorded on the magnetic disk 50 shown in FIG. 4, the magnetic head 14 shown in FIG. Concentric circular region 50 on the outer periphery of the magnetic disk 50₁ On track, and moves from the outer circumference to the inner circumference as a whole, and the data recording area 50_1a , ..., backup data recording area 50_2b Write data (backup data) in the order of.
[0056]
When data is read from the magnetic disk 50, the outer concentric area 50₁50 to the inner concentric region 50₇ Since the data has been written so far, the magnetic head 14 theoretically reads the data while moving in a wide range from the outer periphery to the inner periphery.
[0057]
In the above description, the backup data recording area 50 shown in FIG._1bAlthough the example of writing the backup data has been described in the above, from the viewpoint of preventing only the fixed point floating, the backup data may not be written and may be used as an unused area.
[0058]
As described above, according to one embodiment, as shown in FIG. 2, the region has a plurality of regions that are concentrically divided from the outer periphery toward the inner periphery, and one of each of the regions is skipped. An area is a data recording area 11 in which data is recorded.₁, 11_ThreeAnd 11_FiveTherefore, the data is recorded in a wide range from the outer periphery to the inner periphery, and the reliability can be improved by preventing the magnetic head 14 from flying up at a fixed point.
[0059]
According to one embodiment, the data recording area 11₁, 11_ThreeAnd 11_FiveBackup data recording area 11 in which backup data is recorded in each area other than₂, 11_Four, 11₆ Therefore, the utilization efficiency of the magnetic disk 11 can be increased. In FIG. 3 and FIG. 4 to be described later, the use efficiency can be increased by the backup data recording area.
[0060]
Further, according to the embodiment, as shown in FIG. 3, the outer periphery data recording area 40 in which data is recorded.₁ Is set to the outer periphery, and the inner periphery data recording area 40 in which data is recorded₂Is set to the inner circumference, data is recorded in the range of the outer circumference and the inner circumference, the moving distance of the magnetic head 14 is increased, and the reliability can be improved by preventing the fixed point floating.
[0061]
Further, according to one embodiment, as shown in FIG. 4, it has a plurality of regions that are concentrically divided from the outer periphery toward the inner periphery and are divided into a plurality of portions in the circumferential direction. A data recording area 50 in which data is recorded in each area skipped in the radial direction and each area skipped in the circumferential direction._1a..., 50_7a Therefore, the data is recorded in a wide range from the outer periphery to the inner periphery, and the reliability can be improved by preventing the magnetic head 14 from flying up at a fixed point.
[0062]
Although one embodiment of the present invention has been described in detail with reference to the drawings, a specific configuration example is not limited to this one embodiment, and the design can be changed without departing from the gist of the present invention. And the like are included in the present invention.
[0063]
For example, in the magnetic disk 11 shown in FIG. 2 and the magnetic disk 40 shown in FIG. 3, the outer data recording area (used from the outermost circumference) and the inner data recording area (used from the innermost circumference) are alternated. The magnetic head 14 may be moved alternately between the outer periphery and the inner periphery.
[0064]
In addition, when both surfaces of the magnetic disk 11 and the magnetic disk 40 are used as recording areas, the following two address assignment patterns are conceivable.
・ Outer surface → back inner surface → outer surface → back inner surface
・ Outer surface → inner surface → inner surface → outer surface
[0065]
(Supplementary note 1) A magnetic disk as a disk-shaped recording medium having a plurality of concentrically divided regions from the outer periphery to the inner periphery, and each skipped region is a data Is set in a data recording area in which is recorded.
(Supplementary note 2) The magnetic disk according to supplementary note 1, wherein each area other than the data recording area is set as a backup data recording area in which backup data is recorded.
(Supplementary note 3) The magnetic disk according to Supplementary note 1 or 2, wherein each data recording area is given addresses as a whole from the outer periphery toward the inner periphery.
(Supplementary note 4) The magnetic disk according to supplementary note 2 or 3, wherein each backup data recording area is given addresses as a whole from the outer periphery toward the inner periphery.
(Additional remark 5) It is a magnetic disk as a disk-shaped recording medium, the outer periphery data recording area in which data is recorded is set to the outer periphery, and the inner periphery data recording area in which the data is recorded is set to the inner periphery Magnetic disk characterized by being made.
(Supplementary note 6) The magnetic disk according to supplementary note 5, wherein an area between the outer circumference data recording area and the inner circumference data recording area is set as a backup data recording area in which backup data is recorded. .
(Supplementary note 7) The magnetic disk according to supplementary note 5 or 6, wherein in the outer circumference data recording area and the inner circumference data recording area, addresses are generally given from the outer circumference toward the inner circumference.
(Supplementary note 8) The magnetic disk according to supplementary note 6 or 7, wherein in the backup data recording area, an address is given as a whole from the outer periphery toward the inner periphery.
(Supplementary note 9) A magnetic disk as a disk-shaped recording medium, having a plurality of regions concentrically divided from the outer periphery to the inner periphery and divided in the circumferential direction, A magnetic disk, wherein each area skipped in the radial direction and each area skipped in the circumferential direction are set as data recording areas in which data is recorded.
(Supplementary note 10) The magnetic disk according to supplementary note 9, wherein each area other than the data recording area is set as a backup data recording area in which backup data is recorded.
(Supplementary note 11) The magnetic disk according to supplementary note 9 or 10, wherein each data recording area is given addresses as a whole from the outer periphery toward the inner periphery.
(Supplementary note 12) The magnetic disk according to Supplementary note 10 or 11, wherein each backup data recording area is given addresses as a whole from the outer periphery toward the inner periphery.
(Additional remark 13) It is a magnetic disk as a disk-shaped recording medium, Comprising: It has the area | region divided | segmented concentrically from the outer periphery to the inner periphery, and each area | region of one skip in a some area | region is data A magnetic disk set in a data recording area in which is recorded,
A magnetic head for reading / writing data in each data recording area from the outer periphery to the inner periphery;
A magnetic disk drive comprising:
(Supplementary note 14) A magnetic disk as a disk-shaped recording medium, wherein an outer periphery data recording area in which data is recorded is set to the outer periphery, and an inner periphery data recording area in which the data is recorded is set to the inner periphery A magnetic disk,
A magnetic head for reading / writing data in the outer circumference data recording area and the inner circumference data recording area from the outer circumference to the inner circumference;
A magnetic disk drive comprising:
(Supplementary note 15) A magnetic disk as a disk-shaped recording medium, having a plurality of regions concentrically divided from the outer periphery to the inner periphery and divided in the circumferential direction, A magnetic disk in which each area skipped in the radial direction and each area skipped in the circumferential direction is set as a data recording area in which data is recorded;
A magnetic head for reading / writing data in each data recording area from the outer periphery to the inner periphery;
A magnetic disk drive comprising:
[0066]
【The invention's effect】
  As explained above, according to the present invention,When providing a permission area that allows the user access to a part of the recording area, for each divided area in the divided area sandwiched by concentric circles having different radii from the outer periphery to the inner periphery, Since the permitted areas are distributed and arranged, even if a large number of unused areas are generated on the disk medium, the permitted areas can be distributed over the entire disk medium. The reliability can be improved by preventing the problem of floating on the fixed point. There is an effect.
[0067]
  Moreover, according to the present invention,Since the backup data recording area in which the backup data is recorded is distributed and arranged in the divided area where the permission area is not arranged, there is an effect that the use efficiency of the magnetic disk can be improved.
[0068]
  Moreover, according to the present invention,The divided areas are composed of an outer peripheral area, an intermediate area, and an inner peripheral area, and the permission areas are distributed and arranged with respect to the outer peripheral area and the inner peripheral area. It is possible to disperse the permitted areas and increase the reliability of the magnetic head by increasing the moving distance of the magnetic head and preventing the problem of floating at a fixed point.
[0069]
  Moreover, according to the present invention,The segmented area is divided as a region sandwiched by concentric circles with different radii from the outer periphery to the inner periphery, and is divided in the circumferential direction, so it is permitted from the outer periphery to the inner periphery and the same circumference. Since the regions can be dispersed, the reliability can be improved by preventing the problem of floating of the fixed point of the magnetic head.
[0070]
  Moreover, according to the present invention,When providing a permission area that allows the user access to a part of the recording area, for each divided area in the divided area sandwiched by concentric circles having different radii from the outer periphery to the inner periphery, Since it is provided with a magnetic disk in which permitted areas are distributed and a magnetic head that reads / writes data to / from the divided areas, even if a large number of unused areas occur on the disk medium, Since the permitted area can be distributed over the entire disk medium, it is possible to improve the reliability by preventing the problem of floating of the fixed point of the magnetic head.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment according to the present invention.
FIG. 2 is a plan view showing the configuration of the magnetic disk 11 shown in FIG.
FIG. 3 is a plan view showing a configuration of a magnetic disk 40 used in the same embodiment.
FIG. 4 is a plan view showing a configuration of a magnetic disk 50 used in the same embodiment.
FIG. 5 is a plan view for explaining data replacement of a conventional magnetic disk.
[Explanation of symbols]
10 Magnetic disk unit
11 Magnetic disk
14 Magnetic head
17 VCM drive
18 head IC
19 Lead channel
20 Servo demodulator
21 MPU

Claims (5)

A magnetic disk that is a disk-shaped recording medium having a predetermined recording area,
  When providing a permission area for allowing the user access to a part of the recording area, each divided area in each divided area sandwiched by concentric circles having different radii from the outer periphery to the inner periphery. A magnetic disk in which the permitted areas are distributed. 2. The magnetic disk according to claim 1, wherein a backup data recording area in which backup data is recorded is distributed with respect to the divided area where the permission area is not arranged. The said division area consists of an outer periphery area | region, an intermediate | middle area | region, and an inner periphery area | region, The said permission area | region was disperse | distributed and arrange | positioned with respect to the said outer periphery area | region and the said inner periphery area | region. Magnetic disk. The said division | segmentation area | region is divided | segmented as an area | region pinched | interposed by the concentric circle from which each radius differs from outer periphery to inner periphery, and was divided | segmented into the circumferential direction, The Claim 1, 2, or 3 characterized by the above-mentioned. Magnetic disk. A magnetic disk device having a magnetic disk which is a disk-shaped recording medium having a predetermined recording area,
  When providing a permission area for allowing the user access to a part of the recording area, each divided area in each divided area sandwiched by concentric circles having different radii from the outer periphery to the inner periphery. A magnetic disk in which the permitted areas are distributed, and
  A magnetic head for reading / writing data to / from the divided area;
  A magnetic disk drive comprising:

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