Magnetic disk device and rewriting processing method

Abstract

The embodiment provides a magnetic disk device and a rewrite processing method capable of improving write / read processing performance. The magnetic disk device involved in the embodiment comprises: a disk having a first area and a second area, wherein the first area is an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on the side opposite to the first end in a radial direction are written, and the second area is located at a position separated from the first area in a first direction in a radial direction by a gap and is an area where a plurality of tracks are written in an overlapping manner from a second initial track located at a second end in a radial direction to a second last track located at a second other end on the side opposite to the second end in a radial direction along the first direction; a head that writes data to the disk and reads data from the disk; and a controller that rewrites a portion of the plurality of tracks written in an overlapping manner in the second area in a second direction that is opposite to the first direction.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2020-141690 (filing date: August 25, 2020), and the present application incorporates the entire contents of the basic application by reference. Technical Field

[0002] Embodiments of the present invention relate to a magnetic disk device and a rewrite processing method. Background Art

[0003] In recent years, magnetic disk devices with technologies for achieving high recording density have been developed. As magnetic disk devices for achieving high recording density, there are magnetic disk devices that can perform shingled recording (SMR or SWR) in which multiple tracks are written in a radial direction of the disk in an overlapping manner. In addition, as other magnetic disk devices for achieving high recording density, there are also magnetic disk devices that can select between a normal recording type and a shingled recording type in which multiple tracks are written at intervals in the radial direction of the disk.

[0004] These magnetic disk devices record data in a shingled manner according to an area including a predetermined number of tracks or an area (hereinafter sometimes referred to as a band area) in which data of a predetermined data capacity can be recorded in a shingled manner. These magnetic disk devices also need to perform processing of rewriting the data written to the predetermined band area to the same area (hereinafter sometimes referred to as a refresh processing or a rewrite processing), and processing of overwriting data on a part of the predetermined band area (hereinafter sometimes referred to as an overwrite processing), etc. in units of band areas. Therefore, in the magnetic disk device, it takes more time to refresh and overwrite the data written to the predetermined area in the shingled recording type, compared with refreshing and overwriting the data written to the predetermined area in the normal recording type, which is a type of writing to a plurality of tracks arranged continuously in the radial direction of the disk at predetermined intervals. Therefore, the write / read responsiveness of the magnetic disk device capable of performing the shingled recording type may be lower than that of the magnetic disk device that only writes data in the normal recording type. Summary of the invention

[0005] Embodiments of the present invention provide a magnetic disk device and a rewrite processing method capable of improving write / read processing performance.

[0006] The magnetic disk device involved in this embodiment comprises: a disk, which has a first area and a second area, the first area is an area where multiple tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on the side opposite to the first end in the radial direction, the second area is located at a position separated from the first area in the first direction of the radial direction by a gap, and is an area where multiple tracks are written overlappingly along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on the side opposite to the second end in the radial direction; a head, which writes data to the disk and reads data from the disk; and a controller, which rewrites a part of the multiple tracks written overlappingly in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a block diagram showing the structure of the magnetic disk device according to the first embodiment.

[0008] Figure 2 It is a schematic diagram showing an example of a disk involved in this embodiment.

[0009] Figure 3 FIG. 1 is a schematic diagram showing an example of shingled recording processing.

[0010] Figure 4 FIG. 1 is a schematic diagram showing an example of the configuration of the shingled recording band area.

[0011] Figure 5 This is a schematic diagram of an example of a table showing the number of write times.

[0012] Figure 6 FIG. 1 is a schematic diagram showing an example of a write process in a shingled band area.

[0013] Figure 7 This is a schematic diagram showing an example of the rewriting process according to the first embodiment.

[0014] Figure 8 This is a flowchart showing an example of the rewriting processing method according to the first embodiment.

[0015] Fig. 9 This is a schematic diagram showing an example of a read process according to Modification Example 1.

[0016] Fig.10 This is a flowchart showing an example of a reading method according to Modification Example 1.

[0017] Fig.11This is a schematic diagram showing an example of rewriting processing involved in Modification Example 2.

[0018] Fig.12 This is a schematic diagram showing an example of a read process according to Modification 3.

[0019] Fig.13 This is a schematic diagram showing an example of normal recording processing.

[0020] Fig.14 FIG. 1 is a schematic diagram showing an example of the arrangement of a normal recording band area and a shingled recording band area.

[0021] Fig.15 This is a schematic diagram of an example of a table showing the number of write times.

[0022] Fig.16 FIG. 1 is a schematic diagram showing an example of a write process for a normal recording band area and a shingled recording band area.

[0023] Fig.17 This is a schematic diagram showing an example of the rewriting process according to the second embodiment.

[0024] Fig.18 This is a schematic diagram showing an example of rewriting processing involved in Modification Example 4. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments will be described with reference to the drawings. Note that the drawings are examples and do not limit the scope of the invention.

[0026] (First embodiment)

[0027] Figure 1 It is a block diagram showing the structure of the magnetic disk device 1 according to the first embodiment.

[0028] The magnetic disk device 1 includes a head disk assembly (HDA) described later, a driver IC 20, a head amplifier integrated circuit (hereinafter referred to as a head amplifier IC or a preamplifier) ​​30, a volatile memory 70, a nonvolatile memory 80, a buffer memory (cache) 90, and a system controller 130 which is an integrated circuit of one chip. In addition, the magnetic disk device 1 is connected to a host system (hereinafter referred to as a host) 100.

[0029] The HDA includes a magnetic disk (hereinafter referred to as a disk) 10, a spindle motor (hereinafter referred to as an SPM) 12, an arm 13 equipped with a head 15, and a voice coil motor (hereinafter referred to as a VCM) 14. The disk 10 is mounted on the SPM 12 and rotated by the drive of the SPM 12. The arm 13 and the VCM 14 constitute an actuator. The actuator controls the movement of the head 15 mounted on the arm 13 to a predetermined position of the disk 10 by the drive of the VCM 14. Two or more disks 10 and heads 15 may be provided.

[0030] The disk 10 allocates a user data area 10a that can be used by the user, a medium cache (or sometimes also called a medium cache area) 10b that temporarily holds the data (or command) transmitted from the host or the like before writing the data (or command) to a predetermined area of ​​the user data area 10a, and a system area 10c that writes information required for system management. Hereinafter, the direction from the inner circumference toward the outer circumference of the disk 10, or the direction from the outer circumference toward the inner circumference of the disk 10, is referred to as the radial direction. In the radial direction, the direction from the inner circumference toward the outer circumference is referred to as the outer direction (outer side), and the direction from the outer circumference toward the inner circumference is referred to as the inner direction (inner side). The direction that intersects with the radial direction of the disk 10, for example, is orthogonal, is referred to as the circumferential direction. That is, the circumferential direction is equivalent to the direction along the circumference of the disk 10. In addition, a predetermined position in the radial direction of the disk 10 is sometimes referred to as a radial position, and a predetermined position in the circumferential direction of the disk 10 is sometimes referred to as a circumferential position. The radial position and the circumferential position are sometimes referred to as positions. The disk 10 is divided into a plurality of areas (hereinafter sometimes referred to as partitions) according to a predetermined range in the radial direction. A partition may also include a plurality of areas (hereinafter sometimes referred to as band areas) according to a predetermined range in the radial direction. A band area includes a plurality of tracks. For example, a band area is equivalent to an area in which a predetermined number of tracks can be written, or an area in which data of a predetermined data capacity can be written. A track includes a plurality of sectors. Hereinafter, partitions, band areas, and tracks are sometimes referred to as radial areas, respectively. In addition, "track" is used to mean one of the plurality of areas divided in the radial direction of the disk 10, the path of the head 15 at a predetermined radial position, data extending in the circumferential direction of the disk 10, data written in one circle of a track at a predetermined radial position, data written in a predetermined track of the disk 10, a portion of data written in a predetermined track of the disk 10, and various other meanings. The term "sector" is used to refer to one of a plurality of areas obtained by dividing a predetermined track of the disk 10 in the circumferential direction, data written at a predetermined circumferential position at a predetermined radial position of the disk 10, data written in a predetermined sector of a predetermined track of the disk 10, and various other meanings. Sometimes, a "track written to the disk 10" is referred to as a "write track", and a "track read from the disk 10" is referred to as a "read track". Sometimes, a "write track" is abbreviated as a "track", sometimes a "read track" is abbreviated as a "track", and sometimes both a "write track" and a "read track" are referred to as "tracks". Sometimes, the "width of the track in the radial direction" is referred to as a "track width". Sometimes, the "width of the write track in the radial direction" is referred to as a "write track width", and the "width of the read track in the radial direction" is referred to as a "read track width". Sometimes, "write track width" is abbreviated as "track width", "read track width" is abbreviated as "track width", and "write track width and read track width" are collectively referred to as "track width".The “path passing through the center position of the track width of a predetermined track” is referred to as the “track center”. The “path passing through the center position of the write track width of a predetermined write track” is sometimes referred to as the “write track center”, and the “path passing through the center position of the read track width of a read track” is sometimes referred to as the “track center”, and the “read track center” is sometimes referred to as the “track center”, and the “write track center and read track center” are collectively referred to as the “track center”.

[0031] The head 15 has a slider as a main body, and includes a write head 15W and a read head 15R mounted on the slider. The write head 15W writes data to the disk 10. The read head 15R reads the data written on the disk 10. In addition, sometimes the "write head 15W" is simply referred to as the "head 15", sometimes the "read head 15R" is simply referred to as the "head 15", and sometimes the "write head 15W and the read head 15R" are collectively referred to as the "head 15". Sometimes the "center of the head 15" is referred to as the "head 15", the "center of the write head 15W" is referred to as the "write head 15W", and the "center of the read head 15R" is referred to as the "read head 15R". Sometimes the "center of the write head 15W" is simply referred to as the "head 15", and sometimes the "center of the read head 15R" is simply referred to as the "head 15". Sometimes, “positioning the center of the head 15 at the center of the predetermined track” is expressed as “positioning the head 15 at the predetermined track”, “configuring the head 15 at the predetermined track” or “locating the head 15 at the predetermined track”.

[0032] Figure 2 Schematic diagram showing an example of the disk 10 involved in this embodiment. Figure 2 As shown, in the circumferential direction, the direction in which the disk 10 rotates is referred to as the rotation direction. Figure 2 In the example shown, the direction of rotation is indicated as counterclockwise, but the opposite direction (clockwise) is also possible. Figure 2 In the embodiment, the disk 10 is divided into an inner peripheral region IR located inwardly, an outer peripheral region OR located in outwardly, and a middle peripheral region MR located between the inner peripheral region IR and the outer peripheral region OR.

[0033] exist Figure 2 In the example shown, the disk 10 includes a user data area 10a, a media cache 10b, and a system area 10c. Figure 2 In FIG. 1 , the user data area 10a, the media cache 10b, and the system area 10c are arranged in the order described in the outward direction. Figure 2In the embodiment, the media cache 10b is arranged adjacent to the user data area 10a in the outer direction. In other words, the media cache 10b is arranged between the user data area 10a and the system area 10c. Here, "adjacent" includes data, objects, areas, and spaces arranged in contact with each other, and also includes being arranged at predetermined intervals. Figure 2 In the embodiment, the system area 10c is arranged adjacent to the outside direction of the media cache 10b. In addition, the arrangement order of the user data area 10a, the media cache 10b and the system area 10c is not limited to the present embodiment. Figure 2 The order can be any order.

[0034] exist Figure 2 In the example shown, the user data area 10a is arranged from the inner peripheral area IR to the outer peripheral area OR in the radial direction. In other words, the user data area 10a is arranged from the innermost periphery of the disk 10 to a predetermined radial position of the outer peripheral area OR in the radial direction. Figure 2 In the example shown, the media cache 10b is arranged in the outer region OR in the radial direction. In addition, the media cache 10b may be located in the inner region IR or the middle region MR. In addition, the media cache 10b may be dispersedly located in the outer region OR, the middle region MR, and the inner region IR. Figure 2 In the example shown, the system zone 10 c is arranged in the outer peripheral area OR in the radial direction. In other words, the system zone 10 c is arranged from a predetermined position in the outer peripheral area OR to the outermost periphery of the disc 10 .

[0035] Data can be written in the user data area 10a of the disk 10 by shingled writing (SMR or SWR), which is a type of writing the next track to be written by overlapping a portion of the radial direction of a predetermined track. Hereinafter, "writing data by shingled recording" is sometimes referred to as "shingled recording" or "shingled recording processing". In addition, a writing process other than "normal recording processing" is sometimes referred to as "shingled recording processing".

[0036] A band area including a plurality of tracks written in an overlapping manner by shingled recording may be arranged in the user data area 10a of the disk 10. Hereinafter, the "band area including a plurality of tracks written in an overlapping manner by shingled recording" may be referred to as a "shingled recording band area", and the "shingled recording band area" may be referred to as a "band area" for short.

[0037] Data can be written in the medium cache 10b and the system area 10c of the disk 10 in a conventional magnetic recording (CMR) format, which is a format in which data is written to tracks (hereinafter sometimes referred to as adjacent tracks) that are radially adjacent to a predetermined track at a predetermined interval in the radial direction. Hereinafter, "writing data in a conventional recording format" may be referred to as "conventional recording" or "conventional recording processing". In addition, data can be written in the medium cache 10b and the system area 10c of the disk 10 in a recording format other than the conventional recording format, such as a shingled recording format.

[0038] like Figure 2 As shown, the head 15 rotates about the rotation axis relative to the disk 10 by the drive of the VCM 14, moves from the inner direction to the outer direction to be arranged at a predetermined position, or moves from the outer direction to the inner direction to be arranged at a predetermined position.

[0039] The driver IC 20 controls the driving of the SPM 12 and the VCM 14 according to the control of the system controller 130 (specifically, the MPU 60 described later).

[0040] The head amplifier IC (preamplifier) ​​30 includes a read amplifier and a write driver, etc. The read amplifier amplifies the read signal read from the disk 10 and outputs it to the system controller 130 (more specifically, the read / write (R / W) channel 50 described later). The write driver outputs a write current corresponding to the signal output from the R / W channel 50 to the head 15.

[0041] The volatile memory 70 is a semiconductor memory that loses the stored data when the power supply is cut off. The volatile memory 70 stores data required for processing of each part of the magnetic disk device 1, etc. The volatile memory 70 is, for example, a DRAM (Dynamic Random Access Memory) or an SDRAM (Synchronous Dynamic Random Access Memory).

[0042] The nonvolatile memory 80 is a semiconductor memory that records stored data even when power supply is cut off. The nonvolatile memory 80 is, for example, a NOR type or NAND type flash ROM (Flash Read Only Memory: FROM).

[0043] The buffer memory 90 is a semiconductor memory that temporarily records data transmitted and received between the magnetic disk device 1 and the host 100. In addition, the buffer memory 90 may be formed integrally with the volatile memory 70. The buffer memory 90 is, for example, a DRAM, an SRAM (Static Random Access Memory), an SDRAM, a FeRAM (Ferroelectric Random Access Memory), or an MRAM (Magnetoresistive Random Access Memory).

[0044] The system controller (controller) 130 can be implemented, for example, using a large-scale integrated circuit (LSI) called a system-on-a-Chip (SoC) in which multiple components are integrated into a single chip. The system controller 130 includes a hard disk controller (HDC) 40, a read / write (R / W) channel 50, and a microprocessor or micro processing unit (MPU) 60. The HDC 40, the R / W channel 50, and the MPU 60 are electrically connected to each other. The system controller 130 is electrically connected to, for example, a driver IC 20, a head amplifier IC 30, a volatile memory 70, a non-volatile memory 80, a buffer memory 90, and a host system 100.

[0045] The HDC 40 controls data transfer between the host 100 and the R / W channel 50 in accordance with instructions from the MPU 60 described later. The HDC 40 is electrically connected to, for example, a volatile memory 70, a nonvolatile memory 80, a buffer memory 90, and the like.

[0046] The R / W channel 50 performs signal processing of read data and write data according to instructions from the MPU 60. The R / W channel 50 has a circuit or function for modulating write data. In addition, the R / W channel 50 has a circuit or function for measuring the signal quality of read data. The R / W channel 50 is electrically connected to the head amplifier IC 30, etc.

[0047] The MPU 60 is a main controller that controls each part of the magnetic disk device 1. The MPU 60 controls the VCM 14 via the driver IC 20 to perform positioning of the head 15. The MPU 60 controls the write operation of writing data to the disk 10, and selects the storage destination of the write data transmitted from the host 100. In addition, the MPU 60 controls the read operation of reading data from the disk 10, and controls the processing of the read data transmitted from the disk 10 to the host 100. In addition, the MPU 60 manages the area for recording data. The MPU 60 is connected to each part of the magnetic disk device 1. For example, the MPU 60 is electrically connected to the driver IC 20, the HDC 40, and the R / W channel 50.

[0048] The MPU 60 includes a read / write control unit 610, a write count unit 620, and a rewrite (or refresh) control unit 630. The MPU 60 executes the processing of each unit, such as the read / write control unit 610, the write count unit 620, and the rewrite control unit 630, on the firmware. In addition, the MPU 60 may include each unit, such as the read / write control unit 610, the write count unit 620, and the rewrite (or refresh) control unit 630, as a circuit.

[0049] The read / write control unit 610 controls data reading and writing according to commands from the host 100. The read / write control unit 610 controls the VCM 14 via the driver IC 20, positions the head 15 at a predetermined position on the disk 10, and performs reading or writing.

[0050] The read / write control unit 610 writes tracks (or data) in units of band areas, such as shingled recording band areas. The read / write control unit 610 performs shingled recording processing according to commands from the host 100, etc. In other words, the read / write control unit 610 performs shingled recording of data on a predetermined band area (predetermined shingled recording band area) according to commands from the host 100, etc. Hereinafter, in the shingled recording band area, a piece of associated data that is shingled recorded, such as a track that is initially shingled recorded at one end of a plurality of tracks that are shingled recorded, is sometimes referred to as an initial shingled recording track, and a track that is last shingled recorded at the other end opposite to the one end and does not overlap other tracks is referred to as a final shingled recording track. In addition, the read / write control unit 610 writes data or tracks in a predetermined shingled recording band area in a sequential manner. In addition, the read / write control unit 610 may perform normal recording processing according to a command from the host 100 or the like. In other words, the read / write control unit 610 performs normal recording of data according to a command from the host 100 or the like.

[0051] Figure 3is a schematic diagram showing an example of shingled recording processing. Figure 3 The shingled band area SBA is shown in FIG. Figure 3 In the example shown, the shingled recording band area SBA includes tracks STRe, STRe+1, STRe+2, ..., STRe+(n-1), and STRe+n. In the shingled recording band area SBA, tracks STRe to STRe+n are continuously written in an overlapping manner in the radial direction. Figure 3 The forward direction is represented in the radial direction. In the radial direction, the direction of continuous shingled recording of multiple tracks or the direction of sequential and continuous recording is sometimes referred to as the forward direction. That is, the forward direction is equivalent to the direction from the initial shingled recording track toward the last shingled recording track in the radial direction. In the radial direction, the direction opposite to the forward direction is sometimes referred to as the reverse direction. That is, the reverse direction is equivalent to the direction from the last shingled recording track toward the initial shingled recording track in the radial direction. Figure 3 In the radial direction, the forward direction corresponds to the inner direction. In the following description, the forward direction is assumed to correspond to the inner direction. In addition, the forward direction may correspond to a direction different from the inner direction, such as the outer direction. Figure 3 In the embodiment, the track STRe is located at the extreme end (end or one end) SBEe1 in the reverse direction of the shingled recording band area SBA. Figure 3 In , track STRe is equivalent to the initial shingled recording track. Figure 3 In the example, the track STRe+n is located at the end (end or other end) SBEe2 in the forward direction of the shingled recording band area SBA. Figure 3In the figure, track STRe+n is equivalent to the last shingled recording track. Track STRe written on disk 10 by write head 15W is sometimes referred to as write track WTe, track STRe+1 written on disk 10 by write head 15W is referred to as write track WTe+1, track STRe+2 written on disk 10 by write head 15W is referred to as write track WTe+2, track STRe+(n-1) written on disk 10 by write head 15W is referred to as write track WTe+(n-1), and track STRe+n written on disk 10 by write head 15W is referred to as write track WTe+n. Write tracks WTe~WTe+n have the same write track width WTWa. In the following, it is assumed that the write track widths of each write track are the same for explanation. In addition, write tracks WTe~WTe+n may also have different write track widths. The terms "same", "identical", "consistent" and "equivalent" of course include the meaning of being completely identical, and also include the meaning of being different to the extent that they can be considered to be substantially the same. The write tracks WTe (track STRe) to the write tracks WTe+n (track STRe+n) are written in the radial direction at a track pitch WTPa. In addition, the write tracks WTe (track STRe) to the write tracks WTe+n (track STRe+n) can also be written in the radial direction at different track pitches. The track pitch is, for example, equivalent to the distance in the radial direction between the track centers of two adjacent tracks. Figure 3 In the example shown, the track center WTCe of the write track WTe and the track center WTCe+1 of the write track WTe+1 are written at a track pitch WTPa in the radial direction. For example, the track center WTCe+1 of the write track WTe+1 and the track center WTCe+2 of the write track WTe+2 are written at a track pitch WTPa in the radial direction. In addition, for example, the track center WTCe+(n-1) of the write track WTe+(n-1) and the track center WTCe+n of the write track WTe+n are written at a track pitch WTPa in the radial direction. In addition, the write tracks WTe (track STRe) to WTe+n (track STRe+n) are written overlapping with a portion of the previous track (hereinafter sometimes referred to as the previous track) written in the radial direction of each track written sequentially in the forward direction. Figure 3 In the writing, tracks WTe (track STRe) to WTe+n (track STRe+n) are written in an overlapping manner with a length or range (hereinafter sometimes referred to as a radial range or a radial area) OW in the radial direction from the end of the previous track in the forward direction. In the following, the overlapping radial range (or radial area) OW of a predetermined track and a track written in an overlapping manner with the track is sometimes referred to as an overlapping range OW. Figure 3In the writing of tracks WTe (track STRe) to WTe+n (track STRe+n), overlapping writing can be performed with overlapping ranges different from the overlapping range OW. Figure 3 In the figure, the write track WTe (track STRe) is equivalent to the initial shingled recording track STRe, and the write track WTe+n (track STRe+n) is equivalent to the final shingled recording track STRe+n.

[0052] In each track, the area that does not overlap other tracks is sometimes called a read track. Figure 3 In the text, the area of ​​the write track WTe that does not overlap the write track WTe+1 is sometimes called the read track RTe (track STRe), the area of ​​the write track WTe+1 that does not overlap the write track WTe+2 is sometimes called the read track RTe+1 (track STRe+1), and the area of ​​the write track WTe+(n-1) that does not overlap the write track WTe+n is sometimes called the read track RTe+(n-1) (track STRe+(n-1)). In addition, the last shingled recording track STTe+n (write track WTe+n) ​​is sometimes called the read track RTe+n. Figure 3 In the figure, the read tracks RTe (track STRe) to RTe+(n-1) (track STRe+(n-1)) have the same read track width RTWa. In the following, it is assumed that the read track widths of each read track other than the last shingled recording track are the same for explanation. In addition, the read tracks RTe to RTe+(n-1) may also have different read track widths. In addition, the read track RTe+n (last shingled recording track STRe+n) has a read track width RTWb that is larger than the read track width RTWa of the other read tracks RTe to RTe+(n-1). The read track width RTWb is equivalent to the write track width WTWa. In the figure, the read track width RTWb is equivalent to the write track width WTWa. Figure 3 In the example shown, the difference between the read track width RTWb and the overlap range OW of the track STRe+(n-1) and the track STRe+n corresponds to the width RTWa in the radial direction. Figure 3 In the figure, for the sake of convenience, each track is shown as a rectangular shape extending in the circumferential direction with a predetermined track width, but in fact it is curved along the circumferential direction. In addition, each track can also be a wave shape that changes in the radial direction while extending in the circumferential direction.

[0053] exist Figure 3In the example shown, the read / write control unit 610 performs shingled recording in sequence in the forward direction in the order of recording in the shingled recording band area SBA of the user data area 10a for the write tracks WTe, WTe+1, WTe+2, ..., WTe+(n-1), and WTe+n. In other words, the read / write control unit 610 performs overlapping writing in the forward direction in the order of recording in the shingled recording band area SBA of the user data area 10a for the tracks STRe (write track WTe), STRe+1 (write track WTe+1), STRe+2 (write track WTe+2), ..., STRe+(n-1) (write track WTe+(n-1)), and STRe+n (write track WTe+n).

[0054] exist Figure 3 In the example shown, the read / write control unit 610 positions the head 15 at the center of the track WTCe in the shingled recording band area SBA of the user data area 10a to write the write track WTe. The read / write control unit 610 positions the head 15 at the center of the track WTCe+1 which is away from the center of the track WTCe of the write track WTe in the shingled recording band area SBA to shingle-record the write track WTe+1 on the write track WTe. The read / write control unit 610 positions the head 15 at the center of the track WTCe+2 which is away from the center of the track WTCe+1 of the write track WTe+1 in the shingled recording band area SBA to shingle-record the write track WTe+2 on the write track WTe+1. The read / write control unit 610 positions the head 15 at the track center WTCe+(n-1) in the shingled recording band area SBA, which is located at the track center WTCe+n that is away from the track pitch WTPa in the forward direction from the track center WTCe+(n-1) of the write track WTe+(n-1), and records the write track WTe+n in a shingled manner on the write track WTe+(n-1).

[0055] Figure 4 FIG. 2 is a schematic diagram showing an example of the configuration of the shingled band areas SBA1 and SBA2. Figure 4 2 shows two shingled recording band areas SBA (SBA1 and SBA2) arranged adjacent to each other in the radial direction. Figure 4 In the embodiment, the shingled band areas SBA1 and SBA2 have the same radial width (hereinafter sometimes referred to as shingled band width) SBWa. Figure 4In the embodiment, the areas of the shingled recording band areas SBA1 and SBA2 are the same. In addition, the shingled recording band areas SBA1 and SBA2 may also be different shingled recording band widths. In other words, the areas of the shingled recording band areas SBA1 and SBA2 may also be different. In order to reduce the influence of write overflow, leakage magnetic field, etc. generated when data is written to each other's band areas, two band areas adjacent in the radial direction are arranged with a predetermined interval (hereinafter sometimes also referred to as protection track or protection gap) separated. Figure 4 In the embodiment, the shingled recording band area SBA1 and the shingled recording band area SBA2 are arranged to be separated by the length GTa in the radial direction of the protection track (or sometimes also referred to as the protection gap). Hereinafter, the length GTa in the radial direction of the protection track (protection gap or gap) is sometimes referred to as the protection track (or protection gap) GTa. Figure 4 In the figure, for convenience of explanation, the shingled band area SBA (SBA1) and the shingled band area SBA (SBA2) are shown as rectangular shapes extending in the circumferential direction, but are actually curved along the circumferential direction.

[0056] The read / write control unit 610 sequentially writes a plurality of tracks to the shingled band area SBA1 in the user data area 10a according to a command from the host 100 or the like. The read / write control unit 610 sequentially writes a plurality of tracks to the shingled band area SBA2 radially away from the shingled band area SBA1 by a guard gap GTa in the user data area 10a according to a command from the host 100 or the like.

[0057] The write counter section 620 counts the number of times data is written (hereinafter sometimes referred to as the number of writes). The write counter section 620 counts the number of times data is written to an area (hereinafter sometimes referred to as a proximity area) located within a predetermined range from an area as an object (hereinafter sometimes referred to as an object area) in a radial direction (hereinafter sometimes referred to as a proximity area) (hereinafter sometimes referred to as the proximity area write number). For example, the write counter section 620 counts the number of times data is written to a proximity area (hereinafter sometimes referred to as a forward proximity area) located within a predetermined range from the object area in the forward direction (hereinafter sometimes referred to as a forward proximity area). In addition, for example, the write counter section 620 counts the number of times data is written to a proximity area (hereinafter sometimes referred to as a reverse proximity area) located within a predetermined range from the object area in the reverse direction (hereinafter sometimes referred to as a reverse proximity area). The write counter section 620 may also store the number of writes as a table in a predetermined recording area, such as the system area 10c of the disk 10, the volatile memory 70, the non-volatile memory 80, or the buffer memory 90.

[0058] When data is written to a proximity area located within a predetermined range from the object area in a radial direction, the write count unit 620 increases (increments) the number of writes to the proximity area by a predetermined value. For example, when data is written to a proximity area located within a predetermined range from the object area in a radial direction, the write count unit 620 increases (increments) the number of writes to the proximity area by 1. When data is written to a forward proximity area, the write count unit 620 increases (increments) the number of writes to the forward proximity area by a predetermined value. For example, when data is written to the forward proximity area, the write count unit 620 increases (increments) the number of writes to the forward proximity area by 1. When data is written to a reverse proximity area, the write count unit 620 increases (increments) the number of writes to the reverse proximity area by a predetermined value. For example, when data is written to the reverse proximity area, the write count unit 620 increases (increments) the number of writes to the reverse proximity area by 1.

[0059] The write counter unit 620 counts the number of writes (hereinafter sometimes referred to as the number of adjacent area writes) to an area adjacent to the object area in the radial direction (hereinafter sometimes referred to as the adjacent area). For example, the write counter unit 620 counts the number of adjacent area writes (hereinafter sometimes referred to as the number of forward adjacent area writes) to an adjacent area adjacent to the object area in the forward direction (hereinafter sometimes referred to as the forward adjacent area). In addition, for example, the write counter unit 620 counts the number of adjacent area writes (hereinafter sometimes referred to as the number of reverse adjacent area writes) to an adjacent area adjacent to the object area in the reverse direction (hereinafter sometimes referred to as the reverse adjacent area).

[0060] When data is written to an adjacent area that is radially adjacent to the object area, the write counter unit 620 increases (increments) the number of writes to the adjacent area by a predetermined value. For example, when data is written to an adjacent area that is radially adjacent to the object area, the write counter unit 620 increases (increments) the number of writes to the adjacent area by 1. When data is written to a forward adjacent area, the write counter unit 620 increases (increments) the number of writes to the forward adjacent area by a predetermined value. For example, when data is written to a forward adjacent area, the write counter unit 620 increases (increments) the number of writes to the forward adjacent area by 1. When data is written to a reverse adjacent area, the write counter unit 620 increases (increments) the number of writes to the reverse adjacent area by a predetermined value. For example, when data is written to a reverse adjacent area, the write counter unit 620 increases (increments) the number of writes to the reverse adjacent area by 1.

[0061] The write counting unit 620 counts the number of writes (hereinafter sometimes referred to as the number of adjacent band writes) when data is written to a band area (hereinafter sometimes referred to as the adjacent band area) that is radially adjacent to a band area that is an object (hereinafter sometimes referred to as the object band area). In other words, the write counting unit 620 counts the number of writes (hereinafter sometimes referred to as the number of adjacent band writes or the number of adjacent shingled band writes) when data is written to a shingled recording band area (hereinafter sometimes referred to as the adjacent band area or the adjacent shingled recording band area) that is radially adjacent to a shingled recording band area that is an object (hereinafter sometimes referred to as the object band area or the object shingled recording band area). For example, the write counting unit 620 counts the number of adjacent band writes (hereinafter sometimes referred to as the number of adjacent band writes) when data is written to an adjacent band area (hereinafter sometimes referred to as the forward adjacent band area) that is adjacent to the object band area in the forward direction. In other words, the write counting unit 620 counts the number of adjacent shingled recording tape writes (hereinafter sometimes referred to as the number of forward adjacent recording tape writes or the number of forward adjacent shingled recording tape writes) when data is written to an adjacent shingled recording tape area (hereinafter sometimes referred to as the forward adjacent recording tape area or the forward adjacent shingled recording tape area) that is adjacent to the object shingled recording tape area in the forward direction. In addition, for example, the write counting unit 620 counts the number of adjacent recording tape writes (hereinafter sometimes referred to as the number of reverse adjacent recording tape writes) when data is written to an adjacent recording tape area (hereinafter sometimes referred to as the reverse adjacent recording tape area) that is adjacent to the object recording tape area in the reverse direction. In other words, the write counting unit 620 counts the number of adjacent shingled recording tape writes (hereinafter sometimes referred to as the number of adjacent shingled recording tape writes or the number of reverse adjacent recording tape writes) when data is written to an adjacent shingled recording tape area (hereinafter sometimes referred to as the reverse adjacent recording tape area or the reverse adjacent shingled recording tape area) that is adjacent to the object recording tape area in the reverse direction.

[0062] When data is written to an adjacent band area (adjacent shingled recording band area) that is radially adjacent to the object band area (object shingled recording band area), the write counter unit 620 increases (increments) the adjacent band write count (adjacent shingled recording band write count) by a predetermined value. For example, when data is written to an adjacent band area (adjacent shingled recording band area) that is radially adjacent to the object band area (object shingled recording band area), the write counter unit 620 increases (increments) the adjacent band write count (adjacent shingled recording band write count) by 1. When data is written to a forward adjacent band area (forward adjacent shingled recording band area), the write counter unit 620 increases (increments) the forward adjacent band write count (forward adjacent shingled recording band write count) by a predetermined value. For example, when data is written to the forward adjacent band area (forward adjacent shingled recording band area), the write counter unit 620 increases (increments) the forward adjacent band write count (forward adjacent shingled recording band write count) by 1. When data is written to the reverse adjacent band area (reverse adjacent shingled recording band area), the write counter unit 620 increases (increments) the reverse adjacent band write count (reverse adjacent shingled recording band write count) by a predetermined value. For example, when data is written to the reverse adjacent band area (reverse adjacent shingled recording band area), the write counter unit 620 increases (increments) the reverse adjacent band write count (reverse adjacent shingled recording band write count) by 1.

[0063] The write counting unit 620 counts the number of writes (hereinafter sometimes referred to as the number of near-track writes) in which data is written to a track (hereinafter sometimes referred to as a near-track) located within a predetermined range from the target track (hereinafter sometimes referred to as the target track) or target band area (e.g., the target shingled recording band area) in the radial direction. For example, the write counting unit 620 counts the number of near-track writes (hereinafter sometimes referred to as the number of near-track writes) in which data is written to a near-track located within a predetermined range in the forward direction from the target track or target band area (e.g., the target shingled recording band area). In addition, for example, the write counting unit 620 counts the number of near-track writes (hereinafter sometimes referred to as the number of near-track writes) in which data is written to a near-track located within a predetermined range in the reverse direction from the target track or target band area (e.g., the target shingled recording band area) (hereinafter sometimes referred to as the reverse near-track). In addition, the magnetic track that causes write overflow, leakage magnetic field, etc. to the target area when data is written can be detected by measurement in the manufacturing stage, and the detected magnetic track can be set as the close magnetic track. In addition, the magnetic track that causes write overflow, leakage magnetic field, etc. to the target area when data is written can be detected during the action processing, and the detected magnetic track can be set as the close magnetic track.

[0064] The write counter unit 620 increases (increments) the number of writes to the near track by a predetermined value when data is written to a near track located within a predetermined range in the radial direction from the object track or the object band area (e.g., the object shingled recording band area). For example, the write counter unit 620 increases (increments) the number of writes to the near track by 1 when data is written to a near track located within a predetermined range in the radial direction from the object track or the object band area (e.g., the object shingled recording band area). The write counter unit 620 increases (increments) the number of writes to the near track by a predetermined value when data is written to the forward near track. For example, the write counter unit 620 increases (increments) the number of writes to the forward near track by 1. The write counter unit 620 increases (increments) the number of writes to the reverse near track by a predetermined value when data is written to the reverse near track. For example, when data is written to the reverse approaching track, the write counter unit 620 increases (increments) the reverse approaching track write count by 1.

[0065] The write counting unit 620 counts the number of writes (hereinafter sometimes referred to as the number of adjacent track writes) when data is written to a track (hereinafter sometimes referred to as the adjacent track) that is radially adjacent to the object track or object band area (e.g., the object shingled recording band area). For example, the write counting unit 620 counts the number of adjacent track writes (hereinafter sometimes referred to as the number of forward adjacent track writes) when data is written to an adjacent track (hereinafter sometimes referred to as the forward adjacent track) that is adjacent to the object track or object band area (e.g., the object shingled recording band area) in the forward direction. In addition, for example, the write counting unit 620 counts the number of adjacent track writes (hereinafter sometimes referred to as the number of reverse adjacent track writes) when data is written to an adjacent track (hereinafter sometimes referred to as the reverse adjacent track) that is adjacent to the object track or object band area (e.g., the object shingled recording band area) in the reverse direction.

[0066] The write count unit 620 increases (increments) the number of writes to the adjacent track by a predetermined value when data is written to an adjacent track that is radially adjacent to the object track or the object band area (e.g., the object shingled recording band area). For example, the write count unit 620 increases (increments) the number of writes to the adjacent track by 1 when data is written to an adjacent track that is radially adjacent to the object track or the object band area (e.g., the object shingled recording band area). The write count unit 620 increases (increments) the number of writes to the adjacent track by a predetermined value when data is written to a forward adjacent track. For example, the write count unit 620 increases (increments) the number of writes to the forward adjacent track by 1. The write count unit 620 increases (increments) the number of writes to the reverse adjacent track by a predetermined value when data is written to the reverse adjacent track. For example, when data is written to the reverse adjacent track, the write count unit 620 increases (increments) the reverse adjacent track write count by 1.

[0067] Figure 5 1 is a schematic diagram of an example of table TB1 showing the number of write times. Figure 5 The table TB1 shown includes band areas and write times. Figure 5 The band area of ​​table TB1 includes a shingled recording band area SBA1 and a shingled recording band area SBA2. Figure 4 As shown, Figure 5 The shingled recording band areas SBA1 and SBA2 are arranged adjacent to each other in the radial direction. Figure 4 As shown, the shingled band area SBA2 is adjacent to the shingled band area SBA1 in the forward direction. Figure 5The number of writes in table TB1 includes the reverse adjacent band write number WCO1 and the forward adjacent band write number WCI1 corresponding to the shingled recording band area SBA1, and the reverse adjacent band write number WCO2 and the forward adjacent band write number WCI2 corresponding to the shingled recording band area SBA2. In addition, as the number of writes corresponding to the shingled recording band area SBA1, only the reverse adjacent band write number WCO1 may be maintained in table TB1. As the number of writes corresponding to the shingled recording band area SBA2, only the reverse adjacent band write number WCO2 may be maintained in table TB1. The reverse adjacent band write number WCO1 corresponding to the shingled recording band area SBA1 is equivalent to the number of writes in which data is written to the band area adjacent to the shingled recording band area SBA1 in the reverse direction. The forward adjacent band write number WCI1 corresponding to the shingled recording band area SBA1 is equivalent to the number of writes in which data is written to the shingled recording band area SBA2. The reverse adjacent band write count WCO2 corresponding to the shingled recording band area SBA2 is equivalent to the number of writes to the shingled recording band area SBA1. In addition, the forward adjacent band write count WCI2 corresponding to the shingled recording band area SBA2 is equivalent to the number of writes to the band area adjacent to the shingled recording band area SBA2 in the forward direction. Figure 5 The number of writes in table TB1 may also include the number of reverse adjacent track writes corresponding to shingled recording band area SBA1, the number of forward adjacent track writes corresponding to shingled recording band area SBA1, the number of reverse adjacent track writes corresponding to shingled recording band area SBA2, and the number of forward adjacent track writes corresponding to shingled recording band area SBA2. The number of reverse adjacent track writes corresponding to shingled recording band area SBA1 is, for example, equivalent to the number of writes in which data is written to the last shingled recording track of the reverse adjacent shingled recording band area adjacent to the shingled recording band area SBA1 in the reverse direction. The number of forward adjacent track writes corresponding to shingled recording band area SBA1 is, for example, equivalent to the number of writes in which data is written to the initial shingled recording track of the shingled recording band area SBA2. The number of reverse adjacent track writes corresponding to shingled recording band area SBA2 is, for example, equivalent to the number of writes in which data is written to the last shingled recording track of the shingled recording band area SBA1. The number of writes to the sequentially adjacent tracks corresponding to the shingled band area SBA2 corresponds to, for example, the number of writes to the initial shingled track of the sequentially adjacent shingled band area that is adjacent to the shingled band area SBA2 in the sequential direction.

[0068] exist Figure 5In the example shown, when data is written to the shingled band area (the reverse adjacent shingled band area) SBA1, the write counter section 620 increases (or increments) the reverse adjacent band write count WCO2 by 1. In other words, when data is written to the shingled band area SBA1, the write counter section 620 adds 1 to the reverse adjacent band write count WCO2.

[0069] Furthermore, the write counter unit 620 may also increase (or increment) the reverse adjacent track write count by 1 when data is written to the last shingled recording track of the shingled recording band area (reverse adjacent shingled recording band area) SBA1. In other words, the write counter unit 620 may also add 1 to the reverse adjacent track write count when data is written to the last shingled recording track of the shingled recording band area SBA1.

[0070] exist Figure 5 In the example shown, when data is written to the shingled band area adjacent to the shingled band area SBA2 in the forward direction (forward adjacent shingled band area), the write counter section 620 increases (or increments) the forward adjacent band write count WCI2 by 1. In other words, when data is written to the shingled band area adjacent to the shingled band area SBA2 in the forward direction, the write counter section 620 adds 1 to the forward adjacent band write count WCI2.

[0071] Furthermore, the write count unit 620 may also increase (or increment) the number of writes to the forward adjacent track by 1 when data is written to the initial shingled recording track of the shingled recording band area (forward adjacent shingled recording band area) that is adjacent to the shingled recording band area SBA2 in the forward direction. In other words, the write count unit 620 may also add 1 to the number of writes to the forward adjacent track when data is written to the initial shingled recording track of the shingled recording band area that is adjacent to the shingled recording band area SBA2 in the forward direction.

[0072] exist Figure 5 In the example shown, when data is written to the shingled band area adjacent to the shingled band area SBA1 in the reverse direction (reverse adjacent shingled band area), the write counter section 620 increases (or increments) the reverse adjacent band write count WCO1 by 1. In other words, when data is written to the shingled band area adjacent to the shingled band area SBA1 in the reverse direction, the write counter section 620 adds 1 to the reverse adjacent band write count WCO1.

[0073] Furthermore, the write counter unit 620 may also increase (or increment) the reverse adjacent track write count by 1 when data is written to the last shingled recording track of the shingled recording band area adjacent to the shingled recording band area SBA1 in the reverse direction (reverse adjacent shingled recording band area). In other words, the write counter unit 620 may also increase the reverse adjacent track write count by 1 when data is written to the last shingled recording track of the shingled recording band area adjacent to the shingled recording band area SBA1 in the reverse direction.

[0074] exist Figure 5 In the example shown, when data is written to the shingled band area (forward adjacent shingled band area) SBA2, the write counter section 620 increases (or increments) the forward adjacent band write count WCI1 by 1. In other words, when data is written to the shingled band area SBA2, the write counter section 620 adds 1 to the forward adjacent band write count WCI1.

[0075] Furthermore, the write count unit 620 may also increase (or increment) the number of writes to the forward adjacent track by 1 when data is written to the initial shingled recording track of the shingled recording band area (forward adjacent shingled recording band area) SBA2. In other words, the write count unit 620 may also add 1 to the number of writes to the forward adjacent track when data is written to the initial shingled recording track of the shingled recording band area SBA2.

[0076] The rewrite control unit 630 performs a process of rewriting the same data as the data written in the predetermined area to the area (hereinafter sometimes referred to as a refresh process) or a process of overwriting or rewriting the data in the predetermined area (hereinafter sometimes referred to as an overwrite process or a rewrite process). Hereinafter, the refresh process and the overwrite process (rewrite process) are sometimes referred to as rewriting or rewriting process. The rewrite control unit 630 performs a rewrite process on the area when it is determined that the number of writes corresponding to the predetermined area exceeds the threshold value of the number of writes corresponding to the area (hereinafter sometimes referred to as the write number threshold value). The rewrite control unit 630 rewrites a part of the area when it is determined that the number of writes corresponding to the predetermined area exceeds the write number threshold value corresponding to the area. In other words, the rewrite control unit 630 rewrites the area with data less than the capacity set in advance as the format when it is determined that the number of writes corresponding to the predetermined area exceeds the write number threshold value corresponding to the area. When the rewrite control unit 630 performs the rewrite process on the predetermined area, the write number of the area is reset, for example, to 0.

[0077] The rewrite control unit 630 performs a rewrite process on the object area when it is determined that the number of writes to the proximity area corresponding to the object area (the number of writes to the forward proximity area or the number of writes to the reverse proximity area) exceeds the write number threshold of the number of writes to the proximity area corresponding to the object area (hereinafter sometimes referred to as the write number threshold of the proximity area). The rewrite control unit 630 rewrites a part of the object area when it is determined that the number of writes to the proximity area corresponding to the object area exceeds the write number threshold of the proximity area corresponding to the object area. In other words, the rewrite control unit 630 rewrites the object area with data less than the capacity previously set as the format when it is determined that the number of writes to the proximity area corresponding to the object area exceeds the write number threshold of the proximity area corresponding to the object area.

[0078] The rewrite control unit 630 performs a rewrite process on the object area when it is determined that the number of writes to the adjacent area corresponding to the object area (the number of writes to the forward adjacent area or the number of writes to the reverse adjacent area) exceeds the write number threshold of the number of writes to the adjacent area corresponding to the object area (hereinafter sometimes referred to as the adjacent area write number threshold). The rewrite control unit 630 rewrites a part of the object area when it is determined that the number of writes to the adjacent area corresponding to the object area exceeds the adjacent area write number threshold corresponding to the object area. In other words, the rewrite control unit 630 rewrites data less than the capacity set in advance in the format to the object area when it is determined that the number of writes to the adjacent area corresponding to the object area exceeds the adjacent area write number threshold corresponding to the object area.

[0079] The rewrite control unit 630 performs a rewrite process on the object band area when it is determined that the number of adjacent band writes corresponding to the object band area (the number of forward adjacent band writes or the number of reverse adjacent band writes) exceeds the write number threshold of the number of adjacent band writes corresponding to the object band area (hereinafter sometimes referred to as the adjacent band write number threshold). The rewrite control unit 630 rewrites a part (sector or track) of the object band area when it is determined that the number of adjacent band writes corresponding to the object band area exceeds the adjacent band write number threshold corresponding to the object band area. In other words, the rewrite control unit 630 rewrites the object band area with data less than the capacity set in advance as the format when it is determined that the number of adjacent band writes corresponding to the object band area exceeds the adjacent band write number threshold corresponding to the object band area.

[0080] For example, when the rewrite control unit 630 determines that the number of adjacent shingled tape writes corresponding to the target shingled tape area (the number of adjacent shingled tape writes in the forward direction or the number of adjacent shingled tape writes in the reverse direction) exceeds the write number threshold of the adjacent tape write number corresponding to the target shingled tape area (hereinafter sometimes referred to as the adjacent shingled tape write number threshold), the rewrite control unit 630 performs a rewrite process on the target shingled tape area. When the rewrite control unit 630 determines that the number of adjacent shingled tape writes corresponding to the target shingled tape area exceeds the adjacent shingled tape write number threshold corresponding to the target shingled tape area, the rewrite control unit 630 rewrites a portion (sector or track) of the target shingled tape area. In other words, when the rewrite control unit 630 determines that the number of adjacent shingled tape writes corresponding to the target shingled tape area exceeds the adjacent shingled tape write number threshold corresponding to the target shingled tape area, the rewrite control unit 630 rewrites data less than the capacity set in advance in the format to the target shingled tape area.

[0081] For example, when the rewrite control unit 630 determines that the number of writes to the forward adjacent shingled recording band exceeds the adjacent shingled recording band write number threshold corresponding to the target shingled recording band area, it rewrites the last shingled recording track of the target shingled recording band area at the same position.

[0082] For example, when it is determined that the reverse adjacent band write count exceeds the threshold value of the adjacent shingled recording band write count corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites the initial shingled recording track of the target shingled recording band area by shifting (offsetting) in the reverse direction. In other words, when it is determined that the reverse adjacent band write count exceeds the threshold value of the adjacent shingled recording band write count corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites the initial shingled recording track of the target shingled recording band area by positioning the target position at the time of writing before the initial shingled recording track of the target shingled recording band area is rewritten (hereinafter sometimes referred to as the original write position) after the initial shingled recording track is rewritten, which is offset in the reverse direction. For example, when the rewrite control unit 630 determines that the number of writes to the adjacent shingled recording band in the reverse direction exceeds the threshold value of the number of writes to the adjacent shingled recording band corresponding to the object shingled recording band area, the rewrite control unit 630 rewrites the initial shingled recording track by shifting (offsetting) it in the reverse direction from the original write position by more than the radial length of the overlapping range of the initial shingled recording track of the object shingled recording band area and the track written overlapping with the initial shingled recording track, and below the protection track. In addition, when it is determined that the number of writes to the adjacent shingled recording tape in the reverse direction exceeds the threshold number of writes to the adjacent shingled recording tape corresponding to the object shingled recording tape area, the rewrite control unit 630 may rewrite the initial shingled recording track of the object shingled recording tape area by shifting (biasing) in the reverse direction from the original write position to above the overlapping range (hereinafter sometimes referred to as the initial overlapping range) of the initial shingled recording track of the object shingled recording tape area and the track written overlapping with the initial shingled recording track, and below the sum of the initial overlapping range of the object shingled recording tape area and the protection track. The rewrite control unit 630 may also rewrite the initial shingled recording track of the object shingled recording band area by shifting (biasing) from the original write position in the reverse direction above the initial overlapping range of the object shingled recording band area and below the sum of the initial overlapping range of the object shingled recording band area, the protection track and the final overlapping range of the shingled recording band area adjacent to the object shingled recording band area in the reverse direction, when it is determined that the number of write times of the reverse adjacent shingled recording band exceeds the threshold value of the number of write times of the adjacent shingled recording band area corresponding to the object shingled recording band area.

[0083] The rewrite control unit 630 performs a rewrite process on the object track or the object band area when it is determined that the number of near-track writes (forward near-track writes or reverse near-track writes) corresponding to the object track or the object band area exceeds the write count threshold of the near-track write count corresponding to the object track or the object band area (hereinafter sometimes referred to as the near-track write count threshold). The rewrite control unit 630 rewrites a part (sector or track) of the object track or the object band area when it is determined that the number of near-track writes corresponding to the object track or the object band area exceeds the near-track write count threshold corresponding to the object track or the object band area. In other words, the rewrite control unit 630 rewrites the data below the capacity pre-set as the format on the object track or the object band area when it is determined that the number of near-track writes corresponding to the object track or the object band area exceeds the near-track write count threshold corresponding to the object track or the object band area.

[0084] For example, when the rewrite control unit 630 determines that the number of forward close track writes exceeds the close track write number threshold corresponding to the target shingled recording band area, it rewrites the last shingled recording track of the target shingled recording band area at the same position.

[0085] For example, when the rewrite control unit 630 determines that the number of reverse track writes exceeds the threshold number of track writes corresponding to the target shingled recording band area, the initial shingled recording track of the target shingled recording band area is offset (biased) in the reverse direction. In other words, when the rewrite control unit 630 determines that the number of reverse track writes exceeds the threshold number of track writes corresponding to the target shingled recording band area, the initial shingled recording track is rewritten at the rewrite position offset in the reverse direction from the original write position. For example, when the rewrite control unit 630 determines that the number of reverse track writes exceeds the threshold number of track writes corresponding to the target shingled recording band area, the initial shingled recording track is offset (biased) in the reverse direction from the original write position by more than the length of the radial direction of the overlapping range of the initial shingled recording track of the target shingled recording band area and the track written overlapping with the initial shingled recording track, and below the protection track. Furthermore, the rewrite control unit 630 may also rewrite the initial shingled recording track of the target shingled recording band area by shifting (offsetting) the initial overlapping range of the target shingled recording band area in the reverse direction from the original write position and below the sum of the initial overlapping range of the target shingled recording band area and the protection track, if it is determined that the number of reverse close track writes exceeds the threshold number of close track writes corresponding to the target shingled recording band area. The rewrite control unit 630 may also rewrite the initial shingled recording track of the target shingled recording band area by shifting (offsetting) the initial overlapping range of the target shingled recording band area in the reverse direction from the original write position and below the sum of the initial overlapping range of the target shingled recording band area, the protection track, and the final overlapping range of the shingled recording band area adjacent to the target shingled recording band area in the reverse direction, if it is determined that the number of reverse close track writes exceeds the threshold number of close track writes corresponding to the target shingled recording band area.

[0086] The rewrite control unit 630 performs a rewrite process on the object track or the object band area when it is determined that the number of adjacent track writes (the number of forward adjacent track writes or the number of reverse adjacent track writes) corresponding to the object track or the object band area exceeds the write count threshold of the number of adjacent track writes corresponding to the object track or the object band area (hereinafter sometimes referred to as the adjacent track write count threshold). The rewrite control unit 630 rewrites a part (sector or track) of the object track or the object band area when it is determined that the number of adjacent track writes corresponding to the object track or the object band area exceeds the adjacent track write count threshold corresponding to the object track or the object band area. In other words, the rewrite control unit 630 rewrites data below the capacity previously set as the format to the object track or the object band area when it is determined that the number of adjacent track writes corresponding to the object track or the object band area exceeds the adjacent track write count threshold corresponding to the object track or the object band area.

[0087] For example, when the rewrite control unit 630 determines that the number of writes to the adjacent tracks in the forward direction exceeds the adjacent track write number threshold corresponding to the target shingled recording band area, it rewrites the last shingled recording track of the target shingled recording band area at the same position.

[0088] For example, when the rewrite control unit 630 determines that the number of writes to the reverse adjacent track exceeds the threshold number of writes to the adjacent track corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites the initial shingled recording track of the target shingled recording band area by shifting (offsetting) in the reverse direction. In other words, when the rewrite control unit 630 determines that the number of writes to the reverse adjacent track exceeds the threshold number of writes to the adjacent track corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites the initial shingled recording track by shifting (offsetting) in the reverse direction from the original write position by more than the length of the radial direction of the overlapping range of the initial shingled recording track of the target shingled recording band area and the track written overlapping with the initial shingled recording track, and below the protection track. Furthermore, the rewrite control unit 630 may also rewrite the initial shingled recording track of the target shingled recording band area by shifting (offsetting) the initial overlapping range of the target shingled recording band area in the reverse direction from the original write position and below the sum of the initial overlapping range of the target shingled recording band area and the protection track when it is determined that the number of writes to the adjacent tracks in the reverse direction exceeds the threshold number of writes to the adjacent tracks corresponding to the target shingled recording band area. The rewrite control unit 630 may also rewrite the initial shingled recording track of the target shingled recording band area by shifting (offsetting) the initial overlapping range of the target shingled recording band area in the reverse direction from the original write position and below the sum of the initial overlapping range of the target shingled recording band area, the protection track, and the final overlapping range of the shingled recording band area adjacent to the target shingled recording band area in the reverse direction when it is determined that the number of writes to the adjacent tracks in the reverse direction exceeds the threshold number of writes to the adjacent tracks corresponding to the target shingled recording band area.

[0089] Furthermore, for example, when rewriting the initial shingled recording track of the target shingled recording band area, the rewrite control unit 630 may rewrite the initial shingled recording track so that the track width of the initial shingled recording track becomes less than or equal to twice the track pitch.

[0090] The write count threshold for the proximity region, the write count threshold for the adjacent region, the write count threshold for the adjacent band, the write count threshold for the adjacent shingled recording band, the write count threshold for the proximity track, and the write count threshold for the adjacent track, etc., may be the same or different. In addition, the write count threshold for the proximity region, the write count threshold for the adjacent region, the write count threshold for the adjacent band, the write count threshold for the adjacent shingled recording band, the write count threshold for the proximity track, and the write count threshold for the adjacent track, etc., may be the same or different in the value corresponding to the number of writes written in the forward direction and the value corresponding to the number of writes written in the reverse direction, respectively.

[0091] Figure 6 FIG. 2 is a schematic diagram showing an example of a write process for shingled band areas SBA1 and SBA2. Figure 6 2 shows two shingled band areas SBA1 and SBA2 which are arranged adjacent to each other in the radial direction. Figure 6 The shingled band areas SBA1 and SBA2 shown correspond to Figure 4 The shingled recording band areas SBA1 and SBA2 are shown. Figure 6 In the example shown, the shingled recording band area SBA1 includes ..., track STR1(n-2), track STR1(n-1), and track STR1n. In the shingled recording band area SBA1, ... tracks STR1(n-2) to STR1n are continuously written in an overlapping manner in the radial direction. Figure 6 In the example shown, track STR1n corresponds to the last shingled recording track. ... Tracks STR1(n-2) to STR1n are written in the radial direction at a track pitch WTPa. In addition, ... tracks STR1(n-2) to STR1n may be written in the radial direction at different track pitches. Figure 6 In the example shown, the track center WTC1(n-2) of track STR1(n-2) and the track center WTC1(n-1) of track STR1(n-1) are written at a track pitch WTPa in the radial direction. The track center WTC1(n-1) of track STR1(n-1) and the track center WTC1n of track STR1n are written at a track pitch WTPa in the radial direction. In addition, ... tracks STR1(n-2) to STR1n are written so as to partially overlap with the previous tracks in the radial direction. Figure 6 In the above, tracks STR1(n-2) to STR1n are written so as to overlap with the previous tracks with an overlap range OW. Figure 6 In the embodiment, the end SBE12 in the forward direction of the shingled recording band area SBA1 corresponds to the end STE1n2 in the forward direction of the last shingled recording track STR1n. Figure 6In the example shown, the shingled recording band area SBA2 includes tracks STR21, STR22, and STR23. In the shingled recording band area SBA2, tracks STR21 to STR23 are continuously overlapped and written in the radial direction. Figure 6 In the example shown, track STR21 corresponds to the initial shingled recording track. Tracks STR21 to STR23 ... are written in the radial direction at a track pitch WTPa. In addition, tracks STR21 to STR23 may be written at different track pitches in the radial direction. Figure 6 In the example shown, the track center WTC21 of track STR21 and the track center WTC22 of track STR22 are written at a track pitch WTPa in the radial direction. The track center WTC22 of track STR22 and the track center WTC23 of track STR23 are written at a track pitch WTPa in the radial direction. In addition, tracks STR21 to STR22 ... are written so as to overlap with a portion of the previous track in the radial direction. Figure 6 In the writing, tracks STR21 to STR22, ... are written so as to overlap with the previous tracks with an overlap range OW. Figure 6 In FIG. 1 , the reverse end SBE21 of the shingled recording band area SBA2 corresponds to the reverse end STE211 of the initial shingled recording track STR21. Figure 6 In the example shown, the shingled recording band areas SBA1 and SBA2 are arranged to separate the guard tracks GTa. Figure 6 In the figure, the last shingled recording track STR1n and the initial shingled recording track STR21 are arranged to be separated from the protection track GTa.

[0092] exist Figure 6 In the example shown, the MPU 60 performs shingled recording in the shingled recording band area SBA1 on the initial shingled recording track (not shown), ..., track STR1(n-2), track STR1(n-1), and the last shingled recording track STR1n in a sequential manner in the forward direction in the order of recording. The MPU 60 writes the initial shingled recording track STR21 of the shingled recording band area SBA2 by separating the protection track GTa in the forward direction from the shingled recording band area SBA1. The MPU 60 performs shingled recording in the shingled recording band area SBA2 on the initial shingled recording track STR21, track STR22, track STR23, ..., and the last shingled recording track (not shown) in the shingled recording band area SBA2 in a sequential manner in the forward direction in the order of recording.

[0093] exist Figure 6In the example shown, when the MPU 60 performs shingled recording of at least one track on the shingled recording band area SBA1, the number of writes corresponding to the shingled recording band area SBA2 (the number of reverse adjacent band writes) is increased by 1. For example, when the MPU 60 performs writing on at least one of the tracks STR1(n-2) to STR1n of the shingled recording band area SBA1 arranged in a predetermined range in the reverse direction from the end SBE21 in the reverse direction of the shingled recording band area SBA2, the number of writes corresponding to the shingled recording band area SBA2 (the number of reverse adjacent track writes) is increased by 1. In addition, for example, when the MPU 60 performs writing on the last shingled recording track STR1n of the shingled recording band area SBA1, the number of writes corresponding to the shingled recording band area SBA2 (the number of reverse adjacent track writes) is increased by 1.

[0094] Figure 7 It is a schematic diagram showing an example of the rewriting process involved in this embodiment. Figure 7 Corresponds to Figure 6 .exist Figure 7 The track STR21r in which the track STR21 of the shingled recording band area SBA2 is rewritten is shown. The data written to the track STR21r corresponds to the data written to the track STR21. The track center WTC21r of the track STR21r is equivalent to the radial position after being offset (biased) by the offset (or offset) OFVa from the track center WTC21 of the track STR21 in the reverse direction, for example, toward the shingled recording band area SBA1. In other words, the track STR21r is configured so that the track STR21 is offset in the reverse direction by the offset OFVa. The offset OFVa is, for example, greater than the overlapping range OW of the tracks STR21 and STR22 and less than the overlapping range OW of the tracks STR21 and STR22 + the protection track GTa. In addition, the offset OFVa is, for example, greater than the overlapping range OW of tracks STR21 and STR22 and less than the overlapping range OW of tracks STR21 and STR22 + the overlapping range OW of tracks STR1(n-1) and STR1n + the protection track GTa. In addition, as long as track STR22 can be read, the offset OFVa may be smaller than the overlapping range OW of tracks STR21 and STR22. In addition, as long as track STR1n can be read, the offset OFVa may be larger than the overlapping range OW of tracks STR21 and STR22 + the protection track GTa, or larger than the overlapping range OW of tracks STR21 and STR22 + the overlapping range OW of tracks STR1(n-1) and STR1n + the protection track GTa. Figure 7 In the example shown, the offset OFVa corresponds to the overlapping range OW of the tracks STR21 and STR22. Figure 7 The shingled band width SBWb of the shingled band area SBA2 shown is greater than Figure 6 The shingled band width SBWa of the shingled band area SBA2 shown is an amount by which the initial shingled track STR21 is shifted in the reverse direction, for example, the shift amount OFVa. Figure 7 The protection track GTb ratio shown Figure 6 The protection track GTa shown is smaller than the amount by which the initial shingled recording track STR21 is offset in the reverse direction, for example, the offset OFVa. The track width RTWb of the track STR21r is larger than the track width RTWa of the track STR21 to which the track STR22 is overlapped. Figure 7 In the example shown, the track width RTWb of the track STR21r is larger than the track width RTWa of the track STR21 by an amount corresponding to the overlapping range OW of the tracks STR21 and STR22.

[0095] When MPU60 determines that the number of write times (reverse adjacent shingled recording band write times) of data written to the shingled recording band area SBA1 exceeds the write times threshold value (adjacent shingled recording band write times threshold value) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording track STR21 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording track STR21r in a normal recording type.

[0096] When MPU60 determines that the number of writes (number of reverse track writes) performed on at least one of the tracks STR1(n-2) to STR1n of the shingled recording band area SBA2 exceeds the write number threshold (number of close track writes threshold) corresponding to the shingled recording band area SBA2, it overwrites the initial shingled recording track STR21r of the shingled recording band area SBA2 in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa.

[0097] When MPU60 determines that the number of writes to the track STR1n of the shingled recording band area SBA1 (the number of writes to the adjacent track in the reverse direction) exceeds the write number threshold (the number of writes to the adjacent track) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording track STR21 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording track STR21r in a normal recording type.

[0098] Figure 8 This is a flowchart showing an example of a rewriting processing method according to the present embodiment.

[0099] The MPU 60 counts the number of writes corresponding to the target band area (B801). For example, the MPU 60 counts the number of writes (the number of writes to the reverse adjacent band and the number of writes to the forward adjacent band) of data written to the shingled band area (the reverse adjacent band area and the forward adjacent band area) that is radially adjacent to the target shingled band area. In addition, for example, the MPU 60 counts the number of writes (the number of writes to the reverse adjacent track and the number of writes to the forward adjacent track) of data written to the adjacent tracks (the reverse adjacent track and the forward adjacent track) that are radially adjacent to the target shingled band area.

[0100] The MPU 60 determines whether the number of writes performed in the reverse direction corresponding to the object band area exceeds the write number threshold or is below the write number threshold (B802). For example, the MPU 60 determines whether the number of writes (reverse adjacent shingled band write number) of data written to the shingled band area (reverse adjacent shingled band area) adjacent to the object shingled band area in the reverse direction exceeds the write number threshold of the write number corresponding to the object shingled band area (adjacent shingled band write number threshold) or is below the write number threshold (adjacent shingled band write number threshold). For example, the MPU 60 determines whether the number of writes (reverse adjacent track write number) of data written to the adjacent track (reverse adjacent track) adjacent to the object shingled band area in the reverse direction exceeds the write number threshold of the write number corresponding to the object shingled band area (adjacent track write number threshold) or is below the write number threshold (adjacent track write number threshold).

[0101] When it is determined that the number of writes performed in the reverse direction corresponding to the object band area is below the write number threshold (B802: No), the MPU 60 determines whether the number of writes performed in the forward direction corresponding to the object band area exceeds the write number threshold or is below the write number threshold (B803). For example, the MPU 60 determines whether the number of writes (forward adjacent shingled band write number) of data written to the shingled band area (reverse adjacent shingled band area) adjacent to the object shingled band area in the forward direction exceeds the write number threshold (adjacent shingled band write number threshold) of the number of writes corresponding to the object shingled band area or is below the write number threshold (adjacent shingled band write number threshold). For example, MPU60 determines whether the number of write times (forward adjacent track write times) of data written to the adjacent track (forward adjacent track write times) adjacent to the object shingled recording band area in the forward direction exceeds the write number threshold (adjacent track write number threshold) of the write number corresponding to the object shingled recording band area, or is below the write number threshold (adjacent track write number threshold).

[0102] When it is determined that the number of writes performed in the forward direction corresponding to the object band area is less than the write number threshold (B803: No), the MPU60 enters the processing of B801. For example, when it is determined that the number of writes (forward adjacent shingled band writes) of data written to the shingled band area (forward adjacent shingled band area) adjacent to the object shingled band area in the forward direction is less than the write number threshold (adjacent shingled band write number threshold) of the write number corresponding to the object shingled band area, the MPU60 enters the processing of B801. For example, when it is determined that the number of writes (forward adjacent track writes) of data written to the adjacent track (forward adjacent track) adjacent to the object shingled band area in the forward direction is less than the write number threshold (adjacent track write number threshold) of the write number corresponding to the object shingled band area, the MPU60 enters the processing of B801.

[0103] When it is determined that the number of writes performed in the forward direction corresponding to the target band area exceeds the write number threshold (B803: Yes), the MPU 60 rewrites a portion (sector or track) of the target band area (B804), and ends the processing. For example, when it is determined that the number of writes (forward adjacent shingled band write number) of data written to the shingled band area adjacent to the target shingled band area in the forward direction exceeds the write number threshold (adjacent shingled band write number threshold) of the number of writes corresponding to the target shingled band area, the MPU 60 rewrites the last shingled track of the target shingled band area at the same position, and ends the processing. For example, when it is determined that the number of write times (forward adjacent track write times) in which data is written to an adjacent track (forward adjacent track write times) that is adjacent to the object shingled recording band area in the forward direction exceeds the write times threshold (adjacent track write times threshold) of the write times corresponding to the object shingled recording band area, MPU60 rewrites the last shingled recording track of the object shingled recording band area at the same position and ends the processing.

[0104] When it is determined that the number of writes performed in the reverse direction corresponding to the target band area exceeds the write number threshold value (B802: Yes), the MPU 60 rewrites a portion (sector or track) of the target band area in an offset manner (B805), and ends the processing. For example, when it is determined that the number of writes (reverse adjacent shingled band write number) of data written to a shingled band area (reverse adjacent shingled band area) adjacent to the target shingled band area in the reverse direction exceeds the write threshold value (adjacent shingled band write number threshold value) of the number of writes corresponding to the target shingled band area, the MPU 60 rewrites the last shingled track of the target shingled band area in an offset manner in the reverse direction, and ends the processing. For example, when it is determined that the number of write times (forward adjacent track write times) in which data is written to an adjacent track (forward adjacent track write times) adjacent to the object shingled recording band area in the reverse direction exceeds the write times threshold (adjacent track write times threshold) of the write times corresponding to the object shingled recording band area, MPU60 rewrites the last shingled recording track of the object shingled recording band area at the same position and ends the processing.

[0105] According to the present embodiment, the magnetic disk device 1 counts the number of times data is written to an adjacent band or an adjacent track that is radially adjacent to the target shingled recording band area. When it is determined that the number of times data is written to the shingled recording band area that is adjacent to the target shingled recording band area in the forward direction exceeds the write number threshold of the number of times corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites the last shingled recording track of the target shingled recording band area at the same position. When it is determined that the number of times data is written to the shingled recording band area that is adjacent to the target shingled recording band area in the reverse direction exceeds the write number threshold of the number of times corresponding to the target shingled recording band area, the MPU 60 rewrites the initial shingled recording track of the target shingled recording band area in a reverse biased manner. Therefore, the magnetic disk device 1 can maintain data quality by rewriting a portion of a predetermined band area. Furthermore, the magnetic disk device 1 can reduce (or shorten) the time required for rewriting processing by rewriting a part of a predetermined band area compared to rewriting the entire band area. Therefore, the magnetic disk device can improve the writing / reading processing performance.

[0106] In the first embodiment described above, the magnetic disk device 1 performs the rewrite process of rewriting or overwriting at least one track in an offset manner according to the number of writes to the close portion of the target band area. However, the magnetic disk device 1 may perform the rewrite process of rewriting or overwriting the initial track of the target band area in an offset manner according to the rewrite instruction from the user or the host 100 to rewrite or overwrite a part or all of the initial track of the target band area. In addition, the magnetic disk device 1 may perform the rewrite process of rewriting or overwriting a plurality of tracks continuously written in the forward direction from the initial track of the target band area to the track including the data or the track including the last part of the data in an offset manner according to the rewrite instruction to rewrite or overwrite the data arranged in the middle of the target band area. In this way, by performing the rewrite process of rewriting or overwriting a part or all of the initial track of the target band area or the data arranged in the middle of the target band area from the user or the host 100, the time required for the rewrite process can be reduced (or shortened) compared with the rewrite process of rewriting or overwriting the entire target band area. Therefore, the magnetic disk device 1 can improve the write / read processing performance.

[0107] Next, magnetic disk devices according to modified examples and other embodiments will be described. In the modified examples and other embodiments, the same reference numerals are used for the same parts as those in the first embodiment, and detailed description thereof will be omitted.

[0108] (Variant 1)

[0109] The reading method of the magnetic disk device 1 according to the first modification is different from that of the magnetic disk device 1 according to the first embodiment described above.

[0110] The read / write control unit 610 reads a portion of the band area in a biased (offset) manner when a portion of the band area is rewritten in a biased manner. For example, the read / write control unit 610 reads the initial shingled recording track of the target shingled recording band area in a reverse biased manner when the initial shingled recording track of the target shingled recording band area is rewritten in a reverse biased manner. In other words, the read / write control unit 610 reads the initial shingled recording track by positioning the target position when reading before rewriting the initial shingled recording track (hereinafter sometimes referred to as the original read position) after rewriting the initial shingled recording track in a reverse biased manner (hereinafter sometimes referred to as the rewrite read position).

[0111] Fig. 9 This is a schematic diagram showing an example of a read process according to Modification Example 1. Fig. 9 Corresponds to Figure 7 .exist Fig. 9 The read track center RTC21 of track STR21, which corresponds to the target position when reading track STR21, the read track center RTC21r of track STR21r, which corresponds to the target position when reading track STR21r, and the read track center RTC22 of track STR22, which corresponds to the target position when reading track STR22, are shown in the figure. The read track center RTC21 corresponds to the path passing through the center position of the track width RTWa of track STR21 where overlapping writing of track STR22 is not performed. Fig. 9 In the example, the read track center RTC21 corresponds to the original read position corresponding to the track STR21r. The read track center RTC21r corresponds to the track center WTC21r, which corresponds to the path passing through the center position of the track width RTWb of the track STR21r. Fig. 9 In the embodiment, the read track center RTC21r is equivalent to the rewrite read position corresponding to the track TR21r. The read track center RTC21r is located at a position after the offset OFVb is left in the reverse direction from the read track center RTC21. The read track center RTC22 is equivalent to the path passing through the center position of the track width RTWa of the track STR22 where the overlap writing of the track STR23 is not performed.

[0112] exist Fig. 9In the example shown, the read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC21r (WTC21r) to read the track STR21r. The read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC22 to read the track STR22.

[0113] Fig.10 This is a flowchart showing an example of a reading method according to Modification Example 1.

[0114] MPU 60 determines whether a part of the target band area is written with bias or without bias (B1001). For example, MPU 60 determines whether the initial shingled recording track of the target shingled recording band area is rewritten with reverse bias or without reverse bias.

[0115] When it is determined that the area of ​​a portion of the target band area is written without bias (B1001: No), the MPU 60 reads the area of ​​a portion of the target band area at the original read position (B1002), and ends the processing. For example, when it is determined that the initial shingled recording track of the target shingled recording band area is not rewritten with a bias in the reverse direction, the MPU 60 reads the initial shingled recording track of the target shingled recording band area at the original read position.

[0116] When it is determined that a part of the target band area is written in an offset manner (B1001: Yes), the MPU 60 reads a part of the target band area in an offset manner (B1003), and ends the processing. For example, when it is determined that the initial shingled recording track of the target shingled recording band area is rewritten in an offset manner in the reverse direction, the MPU 60 reads the initial shingled recording track of the target shingled recording band area at the rewrite read position after the offset in the reverse direction from the original read position.

[0117] According to Modification 1, when the initial shingled recording track of the target shingled recording band area is rewritten with a reverse bias, the magnetic disk device 1 reads the initial shingled recording track of the target shingled recording band area with a reverse bias. Therefore, the magnetic disk device can improve the write / read processing performance.

[0118] (Variant 2)

[0119] The magnetic disk device 1 according to the second modification is different from the magnetic disk device 1 according to the first embodiment described above in terms of the rewrite processing method.

[0120] For example, when the rewrite control unit 630 determines that the number of writes to the adjacent shingled recording tape in the forward direction exceeds the threshold number of writes to the adjacent shingled recording tape corresponding to the object shingled recording tape area, it rewrites several tracks arranged continuously in the reverse direction from the last shingled recording track of the object shingled recording tape area at the same position.

[0121] For example, when the rewrite control unit 630 determines that the number of reverse adjacent band writes exceeds the threshold number of adjacent shingled recording band writes corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area with an offset in the reverse direction. In other words, when the rewrite control unit 630 determines that the number of reverse adjacent band writes exceeds the number of adjacent shingled recording band writes corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area by positioning them at respective rewrite positions corresponding to these tracks. For example, when the rewrite control unit 630 determines that the number of writes to the adjacent shingled recording band in the reverse direction exceeds the threshold value of the number of writes to the adjacent shingled recording band corresponding to the object shingled recording band area, it rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track by shifting (offsetting) in the reverse direction from the original positions corresponding to these tracks by more than the length in the radial direction of the overlapping range of the initial shingled recording track of the object shingled recording band area and the tracks written overlapping with the initial shingled recording track and below the protection track. In addition, when it is determined that the number of writes to the adjacent shingled recording tape in the reverse direction exceeds the threshold value of the number of writes to the adjacent shingled recording tape corresponding to the object shingled recording tape area, the rewrite control unit 630 may rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording tape area, by shifting (offsetting) in the reverse direction from the original positions corresponding to these tracks to a level above the overlapping range of the initial shingled recording track of the object shingled recording tape area and the tracks written overlapping with the initial shingled recording track (hereinafter sometimes referred to as the initial overlapping range) and below the sum of the initial overlapping range of the object shingled recording tape area and the protection track. The rewrite control unit 630 may also, when it is determined that the number of write times of the adjacent shingled recording tape in the reverse direction exceeds the threshold value of the number of write times of the adjacent shingled recording tape corresponding to the object shingled recording tape area, rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording tape area, by shifting (offsetting) in the reverse direction from the original positions corresponding to these tracks above the initial overlapping range of the object shingled recording tape area and below the sum of the initial overlapping range of the object shingled recording tape area, the protection track, and the final overlapping range of the shingled recording tape area adjacent to the object shingled recording tape area in the reverse direction.

[0122] For example, when the rewrite control unit 630 determines that the number of forward close-track writes exceeds the close-track write number threshold corresponding to the object shingled recording band area, it rewrites several tracks arranged continuously in the reverse direction from the last shingled recording track of the object shingled recording band area at the same position.

[0123] For example, when the rewrite control unit 630 determines that the reverse track write count exceeds the threshold value of the track write count corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area with an offset (bias) in the reverse direction. In other words, when the rewrite control unit 630 determines that the reverse track write count exceeds the threshold value of the track write count corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area by positioning them at respective rewrite positions corresponding to these tracks. For example, when the rewrite control unit 630 determines that the number of reverse close track writes exceeds the threshold number of close track writes corresponding to the object shingled recording band area, it rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area by shifting (biasing) in the reverse direction from their original positions corresponding to these tracks by more than the length in the radial direction of the overlapping range of the initial shingled recording track and the tracks written in overlap with the initial shingled recording track and below the protection track. In addition, when it is determined that the number of reverse close track writes exceeds the threshold number of close track writes corresponding to the object shingled recording band area, the rewrite control unit 630 may rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area, by offsetting (biasing) them in the reverse direction from their original positions corresponding to the tracks above the initial overlapping range of the object shingled recording band area and below the sum of the initial overlapping range of the object shingled recording band area and the protection track. The rewrite control unit 630 may also, when determining that the number of reverse close track writes exceeds the threshold number of close track writes corresponding to the object shingled recording band area, rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area, offset (bias) in the reverse direction from the original positions corresponding to these tracks above the initial overlapping range of the object shingled recording band area and below the sum of the initial overlapping range of the object shingled recording band area, the protection track, and the final overlapping range of the shingled recording band area adjacent to the object shingled recording band area in the reverse direction.

[0124] For example, when the rewrite control unit 630 determines that the number of writes to the adjacent tracks in the forward direction exceeds the threshold number of writes to the adjacent tracks corresponding to the object shingled recording band area, it rewrites several tracks that are continuously arranged in the reverse direction from the last shingled recording track of the object shingled recording band area at the same position.

[0125] For example, when the rewrite control unit 630 determines that the number of writes to the adjacent tracks in the reverse direction exceeds the threshold number of writes to the adjacent tracks corresponding to the target shingled recording band area, the rewrite control unit 630 rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area with an offset in the reverse direction. In other words, when the rewrite control unit 630 determines that the number of writes to the adjacent tracks in the reverse direction exceeds the threshold number of writes to the adjacent tracks corresponding to the target shingled recording band area, the several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the target shingled recording band area are positioned at the respective rewrite positions corresponding to these tracks to rewrite these tracks. For example, when the rewrite control unit 630 determines that the number of reverse adjacent track writes exceeds the threshold value of the number of adjacent track writes corresponding to the object shingled recording band area, it rewrites several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area by shifting (offsetting) in the reverse direction from the original positions corresponding to these tracks by more than the radial length of the overlapping range of the initial shingled recording track and the tracks written in overlap with the initial shingled recording track and below the protection track. In addition, when it is determined that the number of writes to the adjacent tracks in the reverse direction exceeds the threshold value of the number of writes to the adjacent tracks corresponding to the object shingled recording band area, the rewrite control unit 630 may rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area, by offsetting (biasing) them in the reverse direction from their original positions corresponding to the tracks above the initial overlapping range of the object shingled recording band area and below the sum of the initial overlapping range of the object shingled recording band area and the protection track. The rewrite control unit 630 may also, when it is determined that the number of write times of the adjacent tracks in the reverse direction exceeds the threshold value of the number of write times of the adjacent tracks corresponding to the object shingled recording band area, rewrite several tracks that have been continuously shingled recorded in the forward direction from the initial shingled recording track of the object shingled recording band area, by shifting (offsetting) them in the reverse direction from their original positions corresponding to these tracks above the initial overlapping range of the object shingled recording band area and below the sum of the initial overlapping range of the object shingled recording band area, the protection track, and the final overlapping range of the shingled recording band area adjacent to the object shingled recording band area in the reverse direction.

[0126] Furthermore, when rewriting several tracks that have been continuously shingled in the forward direction from the initial shingled recording track of the target shingled recording band area, the rewrite control unit 630 may rewrite the tracks so that the track width of these tracks becomes less than twice the track pitch.

[0127] Fig.11 This is a schematic diagram showing an example of rewriting processing involved in Modification Example 2. Fig.11 Corresponds to Figure 6 and Figure 7 .exist Fig.11 , which shows track STR22r in which track STR22 of shingled recording band area SBA2 is overwritten. The data written to track STR22r corresponds to the data written to track STR22. Track center WTC22r of track STR22r is equivalent to the radial position after being offset (biased) by offset amount (or offset amount) OFVa from track center WTC22 of track STR22 in the reverse direction, for example, toward the shingled recording band area SBA2. In other words, track STR22r is configured such that track STR22 is offset by offset amount OFVa in the reverse direction. In addition, track STR22r may be configured such that track STR22 is offset by an offset amount different from offset amount OFVa in the reverse direction. Track width RTWb of track STR22r is larger than track width RTWa of track STR22 in which track STR23 is overlapped and written. In Fig.11 In the example shown, the track width RTWb of the track STR22r is larger than the track width RTWa of the track STR22 by an amount corresponding to the overlapping range OW of the tracks STR22 and STR23.

[0128] When MPU60 determines that the number of write times (reverse adjacent shingled recording band write times) of data written to the shingled recording band area SBA1 exceeds the write times threshold value (adjacent shingled recording band write times threshold value) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording tracks STR21 and STR22 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording tracks STR21r and STR22r in a shingled recording type.

[0129] When MPU60 determines that the number of writes (number of reverse track writes) performed on at least one of the tracks STR1(n-2) to STR1n of the shingled recording band area SBA2 exceeds the write number threshold (number of close track writes threshold) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording tracks STR21 and STR22 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording tracks STR21r and STR22r in a shingled recording type.

[0130] When MPU60 determines that the number of writes to track STR1n of shingled recording band area SBA1 (number of writes to adjacent tracks in the reverse direction) exceeds the write number threshold (number of writes to adjacent tracks threshold) corresponding to shingled recording band area SBA2, it causes the initial shingled recording tracks STR21 and STR22 of shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording tracks STR21r and STR22r in a shingled recording type.

[0131] According to variation 2, the magnetic disk device 1 counts the number of times data is written to an adjacent band or an adjacent track that is radially adjacent to the target shingled recording band area. When it is determined that the number of times data is written to the shingled recording band area that is adjacent to the target shingled recording band area in the forward direction exceeds the write number threshold (adjacent shingled recording band write number threshold) of the write number corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites several tracks that are continuously arranged in the reverse direction from the last shingled recording track of the target shingled recording band area at the same position. When it is determined that the number of times data is written to the shingled recording band area that is adjacent to the target shingled recording band area in the reverse direction exceeds the write number threshold (adjacent shingled recording band write number threshold) of the write number corresponding to the target shingled recording band area, the MPU 60 rewrites several tracks that are continuously shingled in the forward direction from the initial shingled recording track of the target shingled recording band area with a bias in the reverse direction. Therefore, the magnetic disk device can improve the write / read processing performance.

[0132] (Variant 3)

[0133] The reading method of the magnetic disk device 1 according to Modification 3 is different from that of the magnetic disk devices 1 according to the first embodiment, Modification 1, and Modification 2 described above.

[0134] For example, when several tracks that have been continuously shingled in the forward direction from the initial shingled recording tracks of the target shingled recording tape area are rewritten in a reverse biased manner, the read / write control unit 610 reads several tracks that have been continuously shingled in the forward direction from the initial shingled recording tracks of the target shingled recording tape area in a reverse biased manner. In other words, when several tracks that have been continuously shingled in the forward direction from the initial shingled recording tracks of the target shingled recording tape area are rewritten in a reverse biased manner, the read / write control unit 610 reads these tracks by positioning at the rewrite read positions corresponding to these tracks after being reverse biased from the original read positions corresponding to these tracks.

[0135] Fig.12 This is a schematic diagram showing an example of a read process according to Modification 3. Fig.12 Corresponds to Fig. 9 and Fig.11 .exist Fig.12 Shown in the figure are read track center RTC21 of track STR21 corresponding to the target position when reading track STR21, read track center RTC21r of track STR21r corresponding to the target position when reading track STR21r, read track center RTC22 of track STR22 corresponding to the target position when reading track STR22, and read track center RTC22r of track STR22r corresponding to the target position when reading track STR22r. Read track center RTC21 is equivalent to the path passing through the center position of the track width RTWa of track STR21 where overlapping writing of track STR22 is not performed. Fig.12 In the example, the read track center RTC21 corresponds to the original read position corresponding to the track STR21r. The read track center RTC21r corresponds to the path passing through the center position of the track width RTWa of the track STR21r where the overlap writing of the track STR22r is not performed. Fig.12 In the read track center RTC21r, the rewrite read position corresponding to the track STR21r is equivalent to the read position corresponding to the track STR21r. The read track center RTC21r is located at a position that is offset from the read track center RTC21 in the reverse direction by an offset amount OFVa. In addition, the read track center RTC21r can also be located at a position that is offset from the read track center RTC21 in the reverse direction by an offset amount other than the offset OFVa. The read track center RTC22 is equivalent to the path passing through the center position of the track width RTWa of the track STR22 where the overlapping writing of the track STR23 is not performed. In Fig.12In the example, the read track center RTC22 corresponds to the original read position corresponding to the track STR22r. The read track center RTC22r corresponds to the track center WTC22r, which is the path passing through the center position of the track width RTWb of the track STR22r. Fig.12 In the read track, the center RTC22r is equivalent to the rewrite read position corresponding to the track STR22r.

[0136] exist Fig.12 In the example shown, the read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC21r (WTC21r) to read the track STR21r. The read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC22 to read the track STR22. The center of the read track RTC22r is located at a position that is offset by an offset OFVb in the reverse direction from the center of the read track RTC22.

[0137] exist Fig.12 In the example shown, the read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC21r to read the track STR21r. The read / write control unit 610 positions the head 15 (read head 15R) at the center of the read track RTC22r to read the track STR22r.

[0138] According to the modification 3, the magnetic disk device 1 reads several tracks which are shingled recorded continuously in the forward direction from the initial shingled recording track of the target shingled recording band area with a reverse bias while rewriting several tracks which are shingled recorded continuously in the forward direction from the initial shingled recording track of the target shingled recording band area with a reverse bias. Therefore, the magnetic disk device can improve the write / read processing performance.

[0139] (Second embodiment)

[0140] The magnetic disk device 1 according to the second embodiment is a magnetic disk device capable of selectively executing a normal recording mode and a shingled recording mode, which is different from the magnetic disk devices 1 according to the first embodiment, modification 1, modification 2, and modification 3 described above.

[0141] MPU60 selects and executes normal recording processing and shingled recording processing according to commands from host 100, etc. In addition, MPU60 can perform only normal recording processing or only shingled recording processing. MPU60 performs normal recording of data on a predetermined band area in a random or sequential manner. Hereinafter, "a band area including at least one track written by normal recording" will be referred to as a "normal recording band area". MPU60 performs normal recording of data on the normal recording band area, and performs shingled recording of data on the shingled recording band area. In addition, MPU60 can perform shingled recording of data on a part of the normal recording band area, and can perform normal recording of data on a part of the shingled recording band area.

[0142] Fig.13 FIG. 1 is a schematic diagram showing an example of a normal recording process. Fig.13 As shown in FIG. 1 , a normal recording band area CBA is shown. Fig.13 In the example shown, the normal recording band area CBA includes track CTRe, track CTRe+1, ..., track CTRe+(n-1), and track CTRe+n. Hereinafter, in the normal recording band area, the track located at the very end in the reverse direction is sometimes referred to as the initial normal recording track, and the track located at the very end in the forward direction is sometimes referred to as the last normal recording track. In addition, the initial normal recording track and the initial shingled recording track are sometimes collectively referred to as the initial track, and the last normal recording track and the last shingled recording track are sometimes collectively referred to as the last track. Fig.13 , the track center TRCe of track CTRe, the track center TRCe+1 of track CTRe+1, ..., the track center TRCe+(n-1) of track CTRe+(n-1), and the track center TRCe+n of track CTRe+n are shown. Fig.13 In the example, the track CTRe is located at the end CBEe1 in the reverse direction of the normal recording band area CBA. Fig.13 In , track CTRe is equivalent to the initial normal recording track. Fig.13 In the example, the track CTRe+n is located at the end CBEe2 in the normal recording band area CBA. Fig.13In , track CTRe+n corresponds to the last normally recorded track. Tracks CTRe to CTRe+n are respectively arranged with a track pitch TRP in the radial direction. The track center TRCe of track CTRe and the track center TRCe+1 of track CTRe+1 are separated by the track pitch TRP in the radial direction. In addition, the track center TRCe+(n-1) of track CTRe+(n-1) and the track center TRCe+n of track CTRe+n are separated by the track pitch TRP in the radial direction. In addition, tracks CTRe to CTRe+n may be respectively arranged with different track pitches in the radial direction. In addition, tracks CTRe to CTRe+n are respectively arranged with gaps CGP in the radial direction. Track CTRe and track CTRe+1 are separated by a gap CGP, and track CTRe+(n-1) and track CTRe+n are separated by a gap CGP. In addition, tracks CTRe to CTRe+n may be respectively arranged with different gaps. In Fig.13 In the figure, for the sake of convenience, each track is shown as a rectangular shape extending in the circumferential direction with a predetermined track width, but in fact it is curved along the circumferential direction. In addition, each track can also be a wave shape that changes in the radial direction while extending in the circumferential direction.

[0143] exist Fig.13 In the example shown, the MPU 60 positions the head 15 at the center of the track TRCe in the normal recording band area CBA of the user data area 10a to perform normal recording on the track CTRe. The MPU 60 positions the head 15 at the center of the track TRCe+1, which is away from the center of the track TRCe of the track CTRe in the normal recording band area CBA, to perform normal recording on the track CTRe+1. The MPU 60 positions the head 15 at the center of the track TRCe+(n-1), which is away from the center of the track TRCe+(n-1) of the track CTRe+(n-1) in the normal recording band area CBA of the user data area 10a, to perform normal recording on the track CTRe+n. In the normal recording band area CBA of the user data area 10a, MPU60 can normally record the tracks CTRe, CTRe+1, ..., CTRe+(n-1) and CTRe+n in a sequential manner, or can normally record the tracks CTRe, CTRe+1, ..., CTRe+(n-1) and CTRe+n in a random manner in the respective predetermined sectors.

[0144] Fig.14 FIG. 2 is a schematic diagram showing an example of the configuration of the normal recording band area CBA1 and the shingled recording band area SBA2. Fig.14FIG. 4 shows a normal recording band area CBA (CBA1) and a shingled recording band area SBA (SBA2) which are arranged adjacent to each other in the radial direction. Fig.14 The width of the normal recording band area CBA1 in the radial direction (hereinafter sometimes referred to as the normal recording band width) CBW is represented in the figure. The normal recording band width CBW may be the same as the shingled recording band width SBWa. In other words, the area of ​​the normal recording band area CBA1 and the area of ​​the shingled recording band area SBA2 may be the same. In addition, the normal recording band width CBW may be different from the shingled recording band width SBWa. In other words, the area of ​​the normal recording band area CBA1 and the area of ​​the shingled recording band area SBA2 may be different. The normal recording band areas and shingled recording band areas adjacent in the radial direction are arranged with protection tracks separated from each other. Fig.14 In the conventional recording band area CBA1 and the shingled recording band area SBA2, a guard track (or sometimes also referred to as a guard gap) GTa is separated and arranged. Fig.14 In the figure, for the sake of convenience, the normal recording band area CBA (CBA1) and the shingled recording band area SBA (SBA2) are shown as rectangular shapes extending in the circumferential direction, but are actually curved along the circumferential direction.

[0145] The MPU 60 writes a plurality of tracks to the normal recording band area CBA1 in the user data area 10a in a sequential or random manner according to the command of the host 100 or the like. The MPU 60 writes a plurality of tracks to the shingled recording band area SBA2 which is radially separated from the normal recording band area CBA1 by the guard gap GTa in the user data area 10a according to the command of the host 100 or the like.

[0146] The MPU60 (write counting unit 620) counts the number of writes (hereinafter sometimes referred to as the adjacent normal recording band write count) of data written to the normal recording band area (hereinafter sometimes referred to as the adjacent normal recording band area) adjacent to the object shingled recording band area in the radial direction. The MPU60 counts the number of adjacent normal recording band writes (hereinafter sometimes referred to as the forward adjacent normal recording band write count) of data written to the adjacent normal recording band area (hereinafter sometimes referred to as the forward adjacent normal recording band area) adjacent to the object normal recording band area in the forward direction. In addition, the MPU60 counts the number of adjacent normal recording band writes (hereinafter sometimes referred to as the reverse adjacent normal recording band write count) of data written to the adjacent normal recording band area (hereinafter sometimes referred to as the reverse adjacent normal recording band area) adjacent to the object normal recording band area in the reverse direction.

[0147] When data is written to an adjacent normal recording band area that is radially adjacent to the object normal recording band area, the MPU60 (write count unit 620) increases (increments) the number of writes to the adjacent normal recording band by a predetermined value. For example, when data is written to an adjacent normal recording band area that is radially adjacent to the object normal recording band area, the MPU60 increases (increments) the number of writes to the adjacent normal recording band by 1. When data is written to a forward-adjacent normal recording band area, the MPU60 increases (increments) the number of writes to the forward-adjacent normal recording band by a predetermined value. For example, when data is written to a forward-adjacent normal recording band area, the MPU60 increases (increments) the number of writes to the forward-adjacent normal recording band by 1. When data is written to a reverse-adjacent normal recording band area, the MPU60 increases (increments) the number of writes to the reverse-adjacent normal recording band by a predetermined value. For example, when data is written to a reverse-adjacent normal recording band area, the MPU60 increases (increments) the number of writes to the reverse-adjacent normal recording band by 1.

[0148] Fig.15 1 is a schematic diagram showing an example of table TB2 showing the number of write times. Fig.15 The table TB2 shown includes band areas, tracks, and write times. Fig.15 The band area of ​​table TB2 includes a normal recording band area CBA1 and a shingled recording band area SBA2. Fig.14 As shown, Fig.15 The normal recording band area CBA1 and the shingled recording band area SBA2 shown in FIG. 1 are arranged adjacent to each other in the radial direction. Fig.14 As shown, the shingled band area SBA2 is adjacent to the normal band area CBA1 in the forward direction. Fig.15 The tracks of table TB2 include tracks CTR11, ..., CTR1(n-1), and CTR1n corresponding to the normal recording band area CBA1. Fig.15 In the diagram, track CTR11 corresponds to the initial normal recording track of the normal recording band area CBA1, and track CTR1n corresponds to the last normal recording track of the normal recording band area CBA1.

[0149] Fig.15The number of writes in table TB2 includes the reverse adjacent track write count CTO11 and the forward adjacent track write count CTI11 corresponding to track CTR11 of the normal recording band area CBA1, ..., the reverse adjacent track write count CTO1(n-1) and the forward adjacent track write count CTI1(n-1) corresponding to track CTR1(n-1) of the normal recording band area CBA1, and the reverse adjacent track write count CTO1n and the forward adjacent track write count CTI1n corresponding to track CTR1n of the normal recording band area CBA1. In addition, as the number of writes corresponding to the normal recording band area CBA1, only the reverse adjacent track write counts CTO11, ..., CTO1(n-1), CTO1n may be maintained in table TB2. The reverse adjacent track write count CTO11 corresponding to track CTR11 is equivalent to the number of writes in which data is written to the last track of the band area adjacent to the normal recording band area CBA1 in the reverse direction. The number of writes CT111 of the forward adjacent tracks corresponding to the track CTR11 is equivalent to the number of writes of data to the adjacent track adjacent to the track CTR11 of the normal recording band area CBA1 in the forward direction. The number of writes CT01(n-1) of the reverse adjacent tracks corresponding to the track CTR1(n-1) is equivalent to the number of writes of data to the adjacent track adjacent to the track CTR1(n-1) of the normal recording band area CBA1 in the reverse direction. The number of writes CT11(n-1) of the forward adjacent tracks corresponding to the track CTR1(n-1) is equivalent to the number of writes of data to the track CTR1n. The number of writes CT01n of the reverse adjacent tracks corresponding to the track CTR1n is equivalent to the number of writes of data to the track CTR1(n-1). The number of writes CT11n of the forward adjacent tracks corresponding to the track CTR1n is equivalent to the number of writes of data to the initial track of the band area adjacent to the normal recording band area CBA1 in the forward direction.

[0150] Fig.15 The number of writes in Table TB2 includes the number of reverse adjacent track writes STO and the number of forward adjacent track writes STI corresponding to the shingled recording band area SBA2. In addition, as the number of writes corresponding to the shingled recording band area SBA2, only the number of reverse adjacent track writes STO may be maintained in Table TB2. The number of reverse adjacent track writes STO corresponding to the shingled recording band area SBA2 is equivalent to the number of writes in which data is written to the last normal recording track CTR1n of the normal recording band area CBA1. The number of forward adjacent track writes STI corresponding to the shingled recording band area SBA2 is equivalent to the number of writes in which data is written to the initial track of the band area adjacent to the shingled recording band area SBA2 in the forward direction. In addition, Fig.15The number of writes in table TB2 may also include the number of reverse track writes and the number of forward track writes corresponding to the shingled recording band area SBA2. The number of reverse track writes corresponding to the shingled recording band area SBA2 is, for example, equivalent to the number of writes in which data is written to the tracks CTR1(n-1) and CTR1n of the normal recording band area CBA1. The number of forward track writes corresponding to the shingled recording band area SBA2 is, for example, equivalent to the number of writes in which data is written to the initial track of the band area adjacent to the shingled recording band area SBA2 in the forward direction and the track adjacent to the initial track in the forward direction.

[0151] exist Fig.15 In the example shown, when data is written to the last normal recording track CTR1n of the normal recording band area CBA1, the MPU 60 increases (or increments) the reverse adjacent track write count STO by 1. In other words, when data is written to the last normal recording track CTR1n of the normal recording band area CBA1, the MPU 60 adds 1 to the reverse adjacent track write count STO.

[0152] Furthermore, when data is written to the last normal recording track CTR1n and the track CTR1(n-1) of the normal recording band area CBA1, the MPU 60 may increase (or increment) the reverse adjacent track write count STO by 1. In other words, when data is written to the last normal recording track CTR1n and the track CTR1(n-1) of the normal recording band area CBA1, the MPU 60 may add 1 to the reverse adjacent track write count STO.

[0153] exist Fig.15 In the example shown, when data is written to the initial track of the band area in the forward direction of the shingled recording band area SBA2, the MPU 60 increases (or increments) the number of writes STI of the forward adjacent tracks by 1. In other words, when data is written to the initial track of the band area in the forward direction of the shingled recording band area SBA2, the MPU 60 adds 1 to the number of writes STI of the forward adjacent tracks.

[0154] Furthermore, when data is written to the initial track of the band area in the forward direction of the shingled recording band area SBA2 and the track adjacent to the initial track in the forward direction, the MPU 60 may increase (or increment) the number of writes STI of the forward adjacent tracks by 1. In other words, when data is written to the initial track of the band area in the forward direction of the shingled recording band area SBA2 and the track adjacent to the initial track in the forward direction, the MPU 60 may add 1 to the number of writes STI of the forward adjacent tracks.

[0155] Fig.16FIG. 2 is a schematic diagram showing an example of a write process of the normal recording band area CBA1 and the shingled recording band area SBA2. Fig.16 2 shows a normal recording band area CBA1 and a shingled recording band area SBA2 which are arranged adjacent to each other in the radial direction. Fig.16 The shingled band area SBA2 shown corresponds to Figure 6 The shingled recording band area SBA2 is shown. Fig.16 In the example shown, the normal recording band area CBA1 includes tracks CTR11, ..., tracks CTR1(n-2), and tracks CTR1n. In the normal recording band area CBA1, tracks CTR11, ..., tracks CTR1(n-1), and tracks CTR1n are written at a track pitch TRP with gaps CGP in the radial direction from adjacent tracks. In addition, tracks CTR11, ..., tracks CTR1(n-1), and tracks CTR1n may also be written at different track pitches in the radial direction. Fig.16 In the example shown, track CTR11 corresponds to the initial normal recording track, and track CTR1n corresponds to the final normal recording track. Fig.16 In the embodiment, the reverse end CBE11 of the normal recording band area CBA1 corresponds to the reverse end CTE111 of the initial normal recording track CTR11. Fig.16 In the example, the forward end CBE12 of the normal recording band area CBA1 corresponds to the forward end CTE1n2 of the last normal recording track CTR1n. Fig.16 In the example shown, the normal recording band area CBA1 and the shingled recording band area SBA2 are arranged with the guard track GTa separated from each other. Fig.16 In the configuration, the final normal recording track CTR1n and the initial shingled recording track STR21 are separated by a protection track GTa.

[0156] exist Fig.16 In the example shown, the MPU 60 performs normal recording on the initial normal recording track CTR11, ..., track CTR1(n-1), and the last normal recording track CTR1n in the normal recording band area CBA1. The MPU 60 writes the initial shingled recording track STR21 of the shingled recording band area SBA2 by separating the guard track GTa in the forward direction from the normal recording band area CBA1.

[0157] exist Fig.16In the example shown, when the last normal recording track CTR1n of the normal recording band area CBA1 is written, the MPU 60 increases the number of writes corresponding to the shingled recording band area SBA2 (the number of reverse adjacent band writes) by 1. For example, when writing is performed on at least one of the tracks CTR1(n-1) and CTR1n of the normal recording band area CBA1 arranged in a predetermined range in the reverse direction from the end SBE21 in the reverse direction of the shingled recording band area SBA2, the MPU 60 may increase the number of writes corresponding to the shingled recording band area SBA2 (the number of reverse adjacent track writes) by 1.

[0158] Fig.17 This is a schematic diagram showing an example of the rewriting process according to the second embodiment. Fig.17 Corresponds to Figure 7 and Fig.16 .

[0159] When MPU60 determines that the number of write times (reverse adjacent track write times) of data written to the track CTR1n of the normal recording band area CBA1 exceeds the write time threshold (adjacent track write time threshold) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording track STR21 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the side of the shingled recording band area SBA1, by an offset amount OFVa to rewrite the initial shingled recording track STR21r in the normal recording type.

[0160] When MPU60 determines that the number of writes (number of reverse track writes) performed on at least one of the tracks CTR1(n-1) and CTR1n of the normal recording band area CBA1 exceeds the write number threshold (number of close track writes threshold) corresponding to the shingled recording band area SBA2, it overwrites the initial shingled recording track STR21r of the shingled recording band area SBA2 in the normal recording type by offsetting it in the reverse direction, for example, toward the shingled recording band area SBA1 side, by an offset amount OFVa.

[0161] According to the second embodiment, the magnetic disk device 1 counts the number of times data is written to the initial track and the last track of the normal recording band area adjacent to the target shingled recording band area in the radial direction. When it is determined that the number of times data is written to the initial normal recording track of the normal recording band area adjacent to the target shingled recording band area in the forward direction exceeds the write number threshold (adjacent track write number threshold) corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites the last shingled recording track of the target shingled recording band area at the same position. When it is determined that the number of times data is written to the last normal recording track of the normal recording band area adjacent to the target shingled recording band area in the reverse direction exceeds the write threshold (adjacent track write number threshold) corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites the initial normal recording track of the target shingled recording band area in a reverse biased manner. Therefore, the magnetic disk device can improve the write / read processing performance.

[0162] (Variant 4)

[0163] The magnetic disk device 1 according to the fourth modification is different from the magnetic disk device 1 according to the second embodiment described above in terms of the rewrite processing method.

[0164] Fig.18 This is a schematic diagram showing an example of rewriting processing involved in Modification Example 4. Fig.18 Corresponds to Figure 7 , Fig.16 as well as Fig.17 .

[0165] When MPU60 determines that the number of write times (reverse adjacent track write times) of data written to the last normal recording track CTR1n of the normal recording band area CBA1 exceeds the write time threshold (adjacent track write time threshold) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording tracks STR21 and STR22 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the normal recording band area CBA1 side, by an offset amount OFVa to rewrite the initial shingled recording tracks STR21r and STR22r in a shingled recording type.

[0166] When MPU60 determines that the number of writes (number of reverse track writes) performed on at least one of the tracks CTR1(n-1) and CTR1n of the normal recording band area CBA1 exceeds the write number threshold (number of close track writes threshold) corresponding to the shingled recording band area SBA2, it causes the initial shingled recording tracks STR21 and STR22 of the shingled recording band area SBA2 to be offset in the reverse direction, for example, toward the normal recording band area CBA1 side, by an offset amount OFVa to rewrite the initial shingled recording tracks STR21r and STR22r in a shingled recording type.

[0167] According to variation 4, the magnetic disk device 1 counts the number of times data is written to the initial track and the last track of the normal recording band area adjacent to the target shingled recording band area in the radial direction. When it is determined that the number of times data is written to the initial normal recording track of the normal recording band area adjacent to the target shingled recording band area in the forward direction exceeds the write number threshold (adjacent track write number threshold) corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites several tracks arranged continuously in the reverse direction from the last shingled recording track of the target shingled recording band area at the same position. When it is determined that the number of times data is written to the last normal recording track of the normal recording band area adjacent to the target shingled recording band area in the reverse direction exceeds the write threshold (adjacent track write number threshold) corresponding to the target shingled recording band area, the magnetic disk device 1 rewrites several tracks that are continuously shingled in the forward direction from the initial normal recording track of the target shingled recording band area in a manner biased in the reverse direction. Therefore, the magnetic disk device can improve the write / read processing performance.

[0168] Several embodiments have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are included in the invention described in the claims and their equivalents.

Claims

1. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When rewriting a part or all of the data in the second initial track, the controller offsets the second initial track from a first position to a second position for rewriting, and the second position is a position separated from the first position by a first interval in the second direction.

2. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When rewriting the first data in the second area, the controller rewrites a plurality of tracks that are continuously overlap-written in the first direction from the second initial track to the first track including the first data by offsetting them in the second direction by a first interval.

3. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When the first write count of data written to the first area exceeds a threshold value corresponding to the second area, the controller overwrites the second initial track by offsetting it from the first position to the second position, wherein the second position is a position separated from the first position by a first interval in the second direction.

4. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When the first write count of data written to the first last track of the first area exceeds a threshold value corresponding to the second area, the controller overwrites the second initial track by offsetting it from the first position to the second position, wherein the second position is a position separated from the first position by a first interval in the second direction.

5. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When the first write count of data written to the first area exceeds a threshold value corresponding to the second area, the controller overwrites multiple tracks that have been continuously and overlappingly written in the first direction from the second initial track by offsetting them by a first interval in the second direction.

6. A magnetic disk device comprising: A disk having a first area and a second area, wherein the first area is an area where a plurality of tracks are written from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction, and the second area is located at a position separated from the first area by a gap in a first direction in the radial direction and is an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction; a head that writes data to and reads data from the disk; as well as a controller that rewrites a portion of the plurality of tracks that have been overlapped and written in the second area with an offset in a second direction, the second direction being a direction opposite to the first direction, When the first write count of data written to the first last track of the first area exceeds a threshold value corresponding to the second area, the controller rewrites multiple tracks that have been continuously and overlappingly written in the first direction from the second initial track by offsetting them by the first interval in the second direction.

7. The magnetic disk device according to claim 1, 3 or 4, The controller is positioned at the second position in the second area to read the second initial track.

8. The magnetic disk device according to claim 2, 5 or 6, The controller reads a plurality of tracks in the second area that have been overlap-written continuously in the first direction from the second initial track, offsetting the first interval in the second direction.

9. The magnetic disk device according to any one of claims 1 to 6, The first interval is smaller than the gap.

10. The magnetic disk device according to claim 9, The first interval corresponds to the length in the radial direction of the region in the second region where the second initial track overlaps with the first track written so as to overlap with the second initial track.

11. The magnetic disk device according to any one of claims 1 to 6, In the first area, overlapping writing is performed on a plurality of tracks from the first initial track to the first final track.

12. The magnetic disk device according to any one of claims 1 to 6, In the first area, a plurality of tracks from the first initial track to the first final track are written at intervals.

13. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When rewriting a part or all of the data in the second initial track, the second initial track is rewritten by being offset from the first position to the second position, wherein the second position is a position separated from the first position by a first interval in the second direction.

14. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When rewriting the first data in the second area, a plurality of tracks continuously overlapped and written in the first direction from the second initial track to the first track including the first data are rewritten by being offset by a first interval in the second direction.

15. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When the first write count of data written to the first area exceeds a threshold value corresponding to the second area, the second initial track is overwritten by offsetting it from the first position to the second position, wherein the second position is a position separated from the first position by a first interval in the second direction.

16. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When the first write count of data written to the first last track of the first area exceeds a threshold value corresponding to the second area, the second initial track is rewritten by offsetting it from the first position to the second position, and the second position is a position away from the first position by a first interval in the second direction.

17. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When the first write count of data written to the first area exceeds a threshold value corresponding to the second area, a plurality of tracks continuously and overlappingly written in the first direction from the second initial track are rewritten by offsetting each other by a first interval in the second direction.

18. A rewrite processing method, applied to a magnetic disk device, the magnetic disk device having a disk, the disk having a first area and a second area, the first area being an area where a plurality of tracks from a first initial track located at a first end in a radial direction to a first last track located at a first other end on a side opposite to the first end in the radial direction are written, the second area being located at a position separated from the first area by a gap in a first direction in the radial direction, and being an area where a plurality of tracks are written in an overlapping manner along the first direction from a second initial track located at a second end in the radial direction to a second last track located at a second other end on a side opposite to the second end in the radial direction, the rewrite processing method comprising: rewriting a portion of the plurality of tracks overlapped in the second region with an offset in a second direction, the second direction being a direction opposite to the first direction; When the first write count of data written to the first last track of the first area exceeds the threshold corresponding to the second area, multiple tracks that have been continuously and overlappingly written in the first direction from the second initial track are rewritten by offsetting the first interval in the second direction.

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