Magnetic disk device and post-code writing method

Abstract

An embodiment provides a magnetic disk device and a post-code writing method capable of improving format efficiency. The magnetic disk device of this embodiment includes: a disk having a first area with a first format efficiency and a second area with a second format efficiency lower than the first format efficiency; a head for writing data to and reading data from the disk; and a controller for selecting a first post-code to be written to the first area and a second post-code to be written to the second area from a plurality of post-codes, and writing the selected post-codes to the first area and the second area, respectively.

Description

[0001] Related Application

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2021-45855 (filing date: March 19, 2021), the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present invention relate to a magnetic disk device and a post-code writing method. Background Art

[0004] There are conventional magnetic recording (CMR) type (or conventional recording type) magnetic disk drives, which write multiple tracks spaced apart in the disk's radial direction; shingled write magnetic recording (SMR or SWR) type magnetic disk drives, which overlap multiple tracks in the disk's radial direction; and hybrid recording type magnetic disk drives, which select between conventional and shingled recording types. Magnetic disks contain servo data such as preambles, servo marks, Gray codes, and postcodes. Magnetic disk drives of conventional, shingled, and hybrid recording types can each contain servo data including corresponding postcodes. Summary of the Invention

[0005] Embodiments of the present invention provide a magnetic disk device and a post-code writing method capable of improving format efficiency.

[0006] The magnetic disk device of this embodiment comprises: a disk having a first area with a first format efficiency and a second area with a second format efficiency lower than the first format efficiency; a head for writing data to the disk and reading data from the disk; and a controller for selecting a first post-code to be written to the first area and a second post-code to be written to the second area from a plurality of post-codes, and writing the selected post-codes to the first area and the second area, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0008] Figure 2 This is a schematic diagram showing an example of the arrangement of servo areas on a disk according to the first embodiment.

[0009] Figure 3 and Figure 4This is a schematic diagram showing an example of a data pattern of a disk track.

[0010] Figures 5 to 13 FIG. 1 is a schematic diagram showing an example of a servo sector in a servo area.

[0011] Figure 14 This is a schematic diagram showing an example of the configuration of the system controller according to this embodiment.

[0012] Figure 15 and Figure 16 This is a diagram showing an example of normal servo readout processing.

[0013] Figure 17 This is a diagram showing an example of short servo processing.

[0014] Figure 18 This is a schematic diagram showing an example of normal recording processing.

[0015] Figure 19 It is a schematic diagram showing an example of shingled recording processing.

[0016] Figure 20A This is a schematic diagram showing an example of a postcode for normal recording mode according to this embodiment.

[0017] Figure 20B It shows Figure 20A The diagram shows an example of the arrangement of post-codes for a normal recording format.

[0018] Figure 21A This is a schematic diagram showing an example of a postcode for the normal recording format according to the first embodiment.

[0019] Figure 21B It shows Figure 21A The diagram shows an example of the arrangement of post-codes for a normal recording format.

[0020] Figure 22A This is a schematic diagram showing an example of a postcode for normal recording mode according to this embodiment.

[0021] Figure 22B It shows Figure 22A The diagram shows an example of the arrangement of post-codes for a normal recording format.

[0022] Figure 23A This is a schematic diagram showing an example of a postcode for the shingled recording type according to this embodiment.

[0023] Figure 23B It shows Figure 23A The diagram shows an example of the configuration of post-codes for the shingled recording format.

[0024] Figure 24A This is a schematic diagram showing an example of a postcode for the shingled recording type according to this embodiment.

[0025] Figure 24B It shows Figure 24A The diagram shows an example of the configuration of post-codes for the shingled recording format.

[0026] Figure 25A This is a schematic diagram showing an example of a post-code for a hybrid recording format according to this embodiment.

[0027] Figure 25B It shows Figure 25A The diagram shows an example of the configuration of the post-code for the hybrid recording format.

[0028] Figure 26A This is a schematic diagram showing an example of a post-code for a hybrid recording format according to this embodiment.

[0029] Figure 26B It shows Figure 26A The diagram shows an example of the configuration of the post-code for the hybrid recording format.

[0030] Figure 27 and Figure 28 This is a schematic diagram showing an example of changes in format loss in the radial direction of the disc.

[0031] Figure 29 This is a flowchart showing an example of a post-code writing processing method according to the present embodiment.

[0032] Figure 30 This is a flowchart showing an example of a post-code reading processing method according to the present embodiment.

[0033] Figure 31 This is a schematic diagram showing an example of the arrangement of servo areas on a disk according to the second embodiment.

[0034] Figure 32 This is a flowchart showing an example of a post-code writing processing method according to the second embodiment.

[0035] Figure 33 This is a flowchart showing an example of a post-code reading method according to the second embodiment. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments will be described with reference to the accompanying drawings. However, the accompanying drawings are merely examples and do not limit the scope of the invention.

[0037] (First embodiment)

[0038] Figure 1 This is a block diagram showing the configuration of the magnetic disk device 1 according to the first embodiment.

[0039] The magnetic disk drive 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 preamplifier) ​​30, a volatile memory 70, a nonvolatile memory 80, a buffer memory (buffer) 90, and a system controller 130, which is a single-chip integrated circuit. Furthermore, the magnetic disk drive 1 is connected to a host system (hereinafter referred to as a host) 100.

[0040] The HAD includes a magnetic disk (hereafter referred to as a disk) 10, a spindle motor (hereafter referred to as an SPM) 12, an arm 13 carrying a head 15, and a voice coil motor (hereafter referred to as a VCM) 14. The disk 10 is mounted on the SPM 12 and rotated by 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 on the disk 10 by the drive of the VCM 14. Two or more disks 10 and heads 15 may be provided.

[0041] The disk 10 allocates data-writable areas to a user data area 10a available to users; a media buffer (also sometimes referred to as a media cache area) 10b, which temporarily stores data (or commands) transmitted from a host computer before being written to a predetermined area within the user data area 10a; and a system area 10c, where information required for system management is stored. The media buffer 10b may not be located on the disk 10. Hereinafter, the direction from the inner periphery to the outer periphery of the disk 10 or the direction from the outer periphery to the inner periphery of the disk 10 is referred to as the radial direction. Within the radial direction, the direction from the inner periphery to the outer periphery is referred to as the outer direction (outer direction), and the direction from the inner periphery to the outer periphery is referred to as the inner direction (inner side). The direction perpendicular to the radial direction of the disk 10 is referred to as the circumferential direction. The circumferential direction corresponds to the direction along the circumference of the disk 10. Predetermined positions in the radial direction of the disk 10 may be referred to as radial positions, while predetermined positions in the circumferential direction of the disk 10 may be referred to as circumferential positions. Radial positions and circumferential positions may also be referred to simply as positions. The term "radial position" may refer to, for example, the distance from the center of rotation of the disk 10 to a predetermined radial position, the distance from the innermost circumference of the disk 10 to a predetermined radial position, or the distance from a predetermined radial position of the disk 10 to another radial position. The disk 10 is divided into multiple areas (hereinafter referred to as "segments") for each predetermined range in the radial direction. A segment includes multiple tracks. The areas of the disk 10 divided in the radial direction may also be referred to as radial areas. Radial areas include segments and tracks. Furthermore, the term "track" can be used to refer to one of the multiple 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 to one track at a predetermined radial position, data written to a predetermined track of the disk 10, a portion of data written to a predetermined track of the disk 10, or other various meanings. The term "sector" can mean one of the multiple areas circumferentially dividing a predetermined track on the disk 10, data written at a predetermined circumferential position at a predetermined radial position on the disk 10, data written in a predetermined sector of a predetermined track on the disk 10, or various other meanings. The "radial width of a track" may be referred to as the "track width." The "path passing through the center of the track width in a predetermined track" may be referred to as the "track center." The "radial width of a sector" may be referred to as the "sector width." The "path passing through the center of the sector width in a predetermined sector" may be referred to as the "sector center." The sector center coincides with the track center. Terms such as "identical," "same," "identical," and "equivalent" naturally include both completely identical and different enough to be considered substantially identical. Hereinafter, the "track center of a predetermined track" may be referred to simply as the "track."In addition, there are cases where the “sector center of a predetermined sector” is simply referred to as “sector”.

[0042] The head 15 is mainly composed of a slider 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. Hereinafter, "writing data" may be referred to as "data writing" or "writing processing". The read head 15R reads data recorded on the disk 10. Hereinafter, "reading data" may be referred to as "data reading" or "reading processing". In addition, the write head 15W may be simply referred to as the head 15, the read head 15R may be simply referred to as the head 15, and the write head 15W and the read head 15R may be collectively referred to as the head 15. The center of the head 15 may be simply referred to as the head 15, the center of the write head 15W may be simply referred to as the write head 15W, and the center of the read head 15R may be simply referred to as the read head 15R. Sometimes, the "center portion of the write head 15W" is simply referred to as "head 15," and sometimes, the "center portion of the read head 15R" is simply referred to as "head 15." Sometimes, "positioning the center portion of the head 15 at the center of a predetermined track" is expressed as "positioning the head 15 at the predetermined track," "arranging the head 15 at the predetermined track," or "locating the head 15 at the predetermined track."

[0043] Figure 2 Schematic diagram showing an example of the arrangement of the servo area SV of the disk 10 according to this embodiment. Figure 2 As shown in FIG. 1 , in the radial direction, the direction toward the outer periphery of the disk 10 is referred to as the outer direction (outer side), and the direction opposite to the outer direction is referred to as the inner direction (inner side). Figure 2 As shown in FIG, 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 shown as counterclockwise, but it can also be the opposite (clockwise). Figure 2 In FIG, the user data area 10 a is divided into an inner peripheral area IR located inward, an outer peripheral area OR located outward, and a middle peripheral area MR located between the inner peripheral area IR and the outer peripheral area OR.

[0044] The disk 10 has multiple servo areas SV and multiple data areas DTR. For example, the multiple servo areas SV can extend radially in the radial direction of the disk 10 and be discretely arranged at predetermined intervals in the circumferential direction. Alternatively, the multiple servo areas SV can extend linearly from the inner circumference to the outer circumference and be discretely arranged at predetermined intervals in the circumferential direction. Alternatively, the multiple servo areas SV can extend spirally from the inner circumference to the outer circumference and be discretely arranged at predetermined intervals in the circumferential direction. Furthermore, the multiple servo areas SV can be arranged in an island-like manner in the radial direction and discretely arranged at predetermined intervals in the circumferential direction. Hereinafter, a servo area SV in a predetermined track may be referred to as a "servo sector." Furthermore, a "servo area SV" may also be referred to as a "servo sector SV." A servo sector includes servo data. Hereinafter, "the arrangement of servo data constituting a servo sector" may also be referred to as a "servo pattern." Furthermore, “servo data written in a servo sector” may be referred to as a “servo sector”.

[0045] A plurality of data regions DTR are respectively arranged between a plurality of servo regions SV. For example, the data region DTR is equivalent to the region between two consecutive servo regions SV in the circumferential direction. Hereinafter, there is also a case where one data region DTR in a predetermined track is referred to as a "data sector". In addition, there is also a case where a "data region DTR" is referred to as a "data sector DTR". The data sector includes user data. In addition, there is also a case where "user data written in the data sector" is referred to as a "data sector". There is also a case where a "data sector" is referred to as "user data". In addition, there is also a case where a "pattern composed of some data" is referred to as a "data pattern". In Figure 2 In the example shown, the data pattern of a predetermined track is composed of servo data (servo sectors) and user data (data sectors).

[0046] The servo area SV includes multiple segment servo areas ZSV, etc. Furthermore, in addition to the segment servo areas ZSV, the servo area SV may also include areas containing gaps, areas containing servo data, and data areas DTR. Multiple segment servo areas ZSV are discretely arranged along the radial direction. Multiple segment servo areas ZSV each extend in the radial direction. There are cases where a segment servo area (servo area) ZSV in a predetermined track is referred to as a "segment servo sector" or "servo sector." There are also cases where a "segment servo area (servo area) ZSV" is referred to as a "segment servo sector ZSV" or "servo sector ZSV." There are also cases where "servo data written in a segment servo sector" is referred to as a "segment servo sector" or "servo sector." Hereinafter, there are also cases where "the configuration of some servo data constituting a segment servo sector" is referred to as a "segment servo pattern" or "servo pattern." Hereinafter, there are also cases where a servo area SV in a predetermined track is referred to as a "segment pattern sector." Furthermore, a "servo area SV" may be referred to as a "segment pattern sector." At least one data item written in a segment pattern sector may also be referred to as a "segment pattern sector." A segment pattern sector includes at least one segment servo sector. Hereinafter, a "data pattern in a segment pattern sector" may also be referred to as a "segment data pattern."

[0047] The servo frequencies of the outwardly positioned segment servo areas in the plurality of segment servo areas ZSV arranged from the inner direction to the outer direction within a predetermined servo area SV are higher than the servo frequencies of the inwardly positioned segment servo areas within the plurality of segment servo areas ZSV. Furthermore, the servo frequencies of the outwardly positioned segment servo sectors within the predetermined segment servo area ZSV are higher than the servo frequencies of the inwardly positioned segment servo sectors within the segment servo area ZSV. The linear velocity of the head 15 relative to the disk 10 is faster at radial positions in the outward direction than at radial positions in the inward direction. Therefore, by making the servo frequencies of the outwardly positioned servo areas higher than those of the inwardly positioned servo areas on the disk 10, as described above, format efficiency can be improved.

[0048] exist Figure 2In the example shown, the servo area SV includes segment servo areas ZSV1, ZSV2, and ZSV3. Segment servo areas ZSV1, ZSV2, and ZSV3 are arranged in a staggered pattern along the radial direction. Segment servo areas ZSV1, ZSV2, and ZSV3 may also be arranged in a stepped pattern along the radial direction. Segment servo area ZSV1 is located inward of segment servo area ZSV2. Segment servo area ZSV3 is located outward of segment servo area ZSV2. For example, segment servo area ZSV1 extends from inner circumference area IR to mid-circumference area MR, segment servo area ZSV2 extends from inner circumference area IR to outer circumference area OR, and segment servo area ZSV3 extends from mid-circumference area MR to outer circumference area OR. Hereinafter, within a predetermined servo area SV, a predetermined radial region where multiple segment servo areas ZSV are arranged in the circumferential direction may be referred to as a segment servo boundary ZB. Segment servo area ZSV1 is located on track TRz1. The outer end of segment servo area ZSV1 and the inner end of segment servo area ZSV2 are located on track TRn. In other words, the outer end of segment servo area ZSV1 and the inner end of segment servo area ZSV2 are located on segment servo boundary ZB1. Segment servo area ZSV2 is located on track TRz2. The outer end of segment servo area ZSV2 and the inner end of segment servo area ZSV3 can be located on track TRm. In other words, the outer end of segment servo area ZSV2 and the inner end of segment servo area ZSV3 are located on segment servo boundary ZB2. Segment servo area ZSV3 is located on track TRz3. For example, the servo frequency of segment servo area ZSV2 is higher than that of segment servo area ZSV1, and the servo frequency of segment servo area ZSV3 is higher than that of segment servo area ZSV2.

[0049] The servo area SV includes, for example, a servo area (hereinafter sometimes referred to as a master servo area) SVO and a servo area (hereinafter sometimes referred to as a slave servo area) SVE. Hereinafter, a master servo area SVO in a predetermined track may be referred to as a "master sector pattern sector SVO," and a slave servo area SVE in a predetermined track may be referred to as a "slave sector pattern sector SVE." Furthermore, the master servo area SVO may be referred to as a "master sector pattern sector SVO," and the slave servo area SVE may be referred to as a "slave sector pattern sector SVE." The data pattern of the master sector pattern sector (hereinafter sometimes referred to as a master sector data pattern) may be the same as or different from the data pattern of the slave sector pattern sector (hereinafter sometimes referred to as a slave sector data pattern).

[0050] exist Figure 2In the example shown, master servo areas SVO and slave servo areas SVE are alternately arranged at intervals in the circumferential direction. For example, one slave servo area SVE is arranged between two master servo areas SVO that are arranged consecutively at intervals in the circumferential direction. In other words, one slave servo area SVE is arranged between two master servo areas SVO that are arranged consecutively at intervals in the circumferential direction. For example, if all servo areas SV on the disk 10 are sequentially numbered, the master servo area SVO corresponds to the odd-numbered servo areas SV, and the slave servo area SVE corresponds to the even-numbered servo areas SV. Furthermore, two or more slave servo areas SVE may be arranged between two master servo areas SVO that are arranged consecutively at intervals in the circumferential direction.

[0051] For example, the master servo area SVO and the slave servo area SVE may consist entirely of servo areas for reading and demodulating servo data (hereinafter, sometimes referred to as normal servo areas). Hereinafter, "reading and demodulating servo data" may be referred to as "servo reading." The master servo area SVO and the slave servo area SVE may also consist of, for example, normal servo areas and servo areas for servo reading a circumferential range of servo data that is smaller than the circumferential range of servo data read in the normal servo areas (hereinafter, sometimes referred to as short servo areas). For example, the master servo area SVO may consist of normal servo areas, while the slave servo area SVE may consist of short servo areas. Alternatively, for example, the master servo area SVO may consist of short servo areas, while the slave servo area SVE may consist of normal servo areas. Hereinafter, one normal servo area in a predetermined track may be referred to as a "normal servo sector," while one short servo area in a predetermined track may be referred to as a "short servo sector." In addition, there are cases where a normal servo area is referred to as a "normal servo sector," and there are cases where a short servo area is referred to as a "short servo sector." There are also cases where "servo data of a normal servo sector" is referred to as "normal servo data," and "servo data of a short servo sector" is referred to as "short servo data." In addition, there are also cases where "normal servo data" is referred to as a "normal servo sector," and there are also cases where "short servo data" is referred to as a "short servo sector." The servo pattern of the normal servo data (hereinafter, sometimes referred to as the normal servo pattern) can be the same as or different from the servo pattern of the short servo sector (hereinafter, sometimes referred to as the short servo pattern). For example, the circumferential length of a short servo sector is shorter than the circumferential length of a normal servo sector. Hereinafter, there are cases where "circumferential length" is simply referred to as "length." In addition, the length of a short servo sector SSV can be the same as or longer than the length of a normal servo sector, for example.

[0052] Below, refer to Figure 3 and Figure 4 , shows an example of a data pattern of a predetermined track of the zone servo boundary ZB of the disk 10.

[0053] Figure 3 1 is a schematic diagram showing an example of a data pattern ZDTP1 of a track TRn of the disk 10. Figure 3 As shown, in the circumferential direction, the direction of the arrow head pointing forward is called the front (front or front direction), and the direction of the arrow head pointing backward is called the rear (or rear direction). Figure 3 The direction of travel is shown in FIG. The direction in which the head 15 sequentially writes and reads data relative to the disk 10 in the circumferential direction (that is, the direction in which the head 15 travels relative to the disk 10 in the circumferential direction) may also be referred to as the direction of travel. For example, the direction of travel is the same as the direction of the rear direction and is opposite to the direction of rotation of the disk 10. Alternatively, the direction of travel may be the same as the direction of rotation of the disk 10.

[0054] exist Figure 3 In the example shown, the track TRn has a data pattern ZDTP1. The data pattern ZDTP1 is composed of a zone pattern sector ZPS (ZPS1) and a data sector DSC of the data area DTR. Figure 3In the example shown, a data pattern ZDTP1 includes a segment pattern sector ZPS1 arranged between two data sectors DSC spaced apart in the circumferential direction. The segment pattern sector ZPS1 includes a segment data pattern ZDP1. The segment data pattern ZDP1 is composed of at least one data element, for example, a segment servo sector ZSVS11 in a segment servo area ZSV (ZSV1), a gap (hereinafter also referred to as a segment servo gap) GP (GP1), and a segment servo sector ZSVS21 in a segment servo area ZSV (ZSV2). In the segment data pattern ZDP1, the segment servo sector ZSVS11, the gap GP (GP1), and the segment servo sector ZSVS21 are arranged in the order listed in the running direction. Hereinafter, in the predetermined segment data pattern, a predetermined segment servo sector arranged circumferentially forward of a predetermined segment servo sector may be referred to as a "front segment servo sector," and a predetermined segment servo sector arranged circumferentially backward of the predetermined segment servo sector may be referred to as a "back segment servo sector." The front segment servo sector ZSVS11 includes a segment servo pattern ZSP11. Furthermore, the back segment servo sector ZSVS21 includes a segment servo pattern ZSP21. For example, the length ZSSL11 of the front segment servo sector ZSVS11 is longer than the length ZSSL21 of the back segment servo sector ZSVS21. The length GPL1 (GPL) of the gap GP1 (GP) corresponds to the circumferential distance between the front segment servo sector ZSVS11 and the back segment servo sector ZSVS21. For example, the length GPL1 of the gap GP1 varies depending on the length ZSSL11 of the front segment servo sector ZSVS11. The length GPL1 of the gap GP1 can be set to a length such that the front-segment servo sector ZSVS11 is not overwritten by the rear-segment servo sector ZSVS21 even when the front-segment servo sector ZSVS11 is written.

[0055] Figure 4 1 is a schematic diagram showing an example of the data pattern ZDTP2 of the track TRm of the disk 10.

[0056] exist Figure 4 In the example shown, the track TRm has a data pattern ZDTP2. The data pattern ZDTP2 is composed of a zone pattern sector ZPS (ZPS2) and a data sector DSC of the data area DTR. Figure 4In the example shown, a data pattern ZDTP2 includes a segment pattern sector ZPS2 arranged between two data sectors DSC spaced apart in the circumferential direction. The segment pattern sector ZPS2 includes a segment data pattern ZDP2. The segment data pattern ZDP2 consists of at least one data element, for example, a segment servo sector ZSVS31 of a segment servo area ZSV (ZSV3), a gap GP (GP2), and a segment servo sector ZSVS22 of the segment servo area ZSV (ZSV2). In the segment data pattern ZDP2, the segment servo sector ZSVS31, the gap GP (GP2), and the segment servo sector ZSVS22 are arranged in the order listed in the forward direction. The leading segment servo sector ZSVS31 includes a segment servo pattern ZSP31. Furthermore, the trailing segment servo sector ZSVS22 includes a segment servo pattern ZSP22. For example, the length ZSSL31 of the leading segment servo sector ZSVS31 is shorter than the length ZSSL22 of the trailing segment servo sector ZSVS22. The length GPL2 (GPL) of the gap GP2 (GP) corresponds to the circumferential distance between the leading segment servo sector ZSVS31 and the trailing segment servo sector ZSVS22. The length GPL2 of the gap GP2 can be the same as or different from the length GPL1 of the gap GP1. For example, the length GPL2 of the gap GP2 varies depending on the length ZSSL31 of the leading segment servo sector ZSVS31. The length GPL2 of the gap GP2 can be set so that even when writing to the leading segment servo sector ZSVS31, the trailing segment servo sector ZSVS22 does not overwrite the length of the leading segment servo sector ZSVS31.

[0057] Figure 5 Schematic diagram showing an example of a servo sector SVS0 of the servo area SV.

[0058] exist Figure 5In the example shown, the servo sector SVS0 of the servo area SV includes predetermined segment servo sectors of the segment servo area ZSV1 (for example, the front segment servo sector ZSVS11, etc.), predetermined segment servo sectors of the segment servo area ZSV2 (for example, the rear segment servo sectors ZSVS21 and ZSVS22, etc.), and predetermined segment servo sectors of the segment servo area ZSV3 (for example, the front segment servo sector ZSVS31, etc.). For example, servo sector SVS0 includes segment servo sector ZSVS11 of segment servo area ZSV1 of track TRn, segment servo sector ZSVS21 of segment servo area ZSV2 of track TRn, segment servo sector ZSVS22 of segment servo area ZSV2 of track TRm, segment servo sector ZSVS31 of segment servo area ZSV3 of track TRm, segment servo sector ZSV1 of track TRz1, segment servo sector ZSV2 of track TRz2, and segment servo sector ZSV3 of track TRz3. Servo sector SVS0 includes servo pattern SVP0. Servo pattern SVP0 is composed of at least one servo data element, such as a preamble, a servo mark or a servo address mark, a gray code, a pad, burst data, and an additional pattern. In the servo pattern SVP0, the preamble, servo mark, Gray code, PAD, burst data, and additional pattern are arranged in the order of these records in the direction of travel. For example, in the servo pattern SVP0, the preamble, servo mark, Gray code, PAD, burst data, and additional pattern are arranged continuously in the direction of travel in the order of these records. That is, in the servo pattern SVP0, the servo marks are adjacent in the direction of travel of the preamble. Here, "adjacent" naturally includes the case where data, objects, areas, and spaces are arranged in contact, and also includes the case where they are arranged at predetermined intervals. Gray codes are adjacent in the direction of travel of the servo marks. PADs are adjacent in the direction of travel of the Gray codes. Burst data are adjacent in the direction of travel of the PADs. Additional patterns are adjacent in the direction of travel of the burst data. In addition, the servo sector SVS0 may not include additional patterns. The additional pattern is, for example, a pattern used to determine the deviation in timing when reading and demodulating data written to the disk 10. The phase data obtained by reading the additional pattern can be used, for example, to determine whether the timing of reading burst data has deviated or not. Hereinafter, the term "timing" may be used to mean "timing after a predetermined time from the reference timing at which the read head 15R reads predetermined data" or "timing at which the read head 15R is positioned at a predetermined circumferential position." The additional pattern is, for example, data different from the post-amble described below.The frequency of the additional pattern is different from the frequency of the preamble, for example. In other words, the frequency of the additional pattern is different from the frequency of the postamble. For example, the frequency of the additional pattern is equal to the frequency of the burst data, for example, the frequency of the N burst and the frequency of the Q burst. For example, the frequency of the additional pattern is a 4-bit periodic pattern. The phase of the additional pattern changes periodically in the circumferential direction. The additional pattern is written as a data pattern whose phase in the radial direction of the disk 10 is equal to that of one servo track period. In other words, the phase of a predetermined additional pattern is equal to the phase of an additional pattern adjacent to the additional pattern in the radial direction. Figure 5 1 shows the length ASL0 of the servo sector SVS0 and the length ADL of the additional pattern. The length ADL of the additional pattern is shorter than the length of the postamble described later. Hereinafter, the length of the PAD and the length of the burst may be constant or different.

[0059] Figure 6 Schematic diagram showing an example of a servo sector SVS1 of the servo area SV.

[0060] exist Figure 6 In the example shown, the servo sector SVS1 of the servo area SV includes the pre-segment servo sector ZSVS11. For example, the servo sector SVS1 includes the segment servo sector ZSVS11 of the segment servo area ZSV1 of the track TRn. The servo sector SVS1 includes a servo pattern SVP1. The servo pattern SVP1 is composed of at least one servo data, for example, a preamble, a servo mark or a servo address mark, a Gray code, a PAD, burst data, and a postcode X1. In the servo pattern SVP1, the preamble, the servo mark, the Gray code, the PAD, the burst data, and the postcode X1 are arranged in the order of these records in the direction of travel. For example, in the servo pattern SVP1, the preamble, the servo mark, the Gray code, the PAD, the burst data, and the postcode X1 are arranged continuously in the order of these records in the direction of travel. The postcodes are adjacent in the direction of travel of the burst data. In addition, the servo sector SVS1 may not include the postcode X1. In Figure 6The figure shows the length ASL1 of the servo sector SVS1, the combined length SVL1 of the preamble, servo mark, and Gray code, and the length PCLX1 of the postamble. The preamble includes preamble information for synchronizing with the reproduced signal of the servo pattern composed of servo marks and Gray code. The servo mark (or servo address mark) includes servo mark information indicating the start of the servo pattern. The Gray code consists of the address of a predetermined track (cylinder address) and the address of a servo sector of the predetermined track. The burst data is data (relative position data) used to detect the radial and / or circumferential position deviation (position error) of the head 15 relative to the center of the predetermined track and consists of a repetitive pattern with a predetermined period. The PAD includes PAD information for synchronization signals such as gaps and servo AGC. The burst data is written in a data pattern in which the phase of the burst data in the radial direction of the disk 10 is reversed by 180° per servo track period. A servo track (servo cylinder) corresponds to a track that is the target of a write or read operation by a command from the host 100 or the like. Burst data is used, for example, to determine the radial and / or circumferential position of the head 15 on the disk 10 (hereinafter referred to as the head position). Burst data includes, for example, N bursts and Q bursts. The N bursts and Q bursts are written as data patterns that are 90° out of phase with each other in the radial direction of the disk 10. The postamble includes data (hereinafter referred to as RRO correction data) used to correct errors caused by jitter (repeatable runout: RRO) synchronized with the rotation of the disk 10 when writing servo data to the disk. This data is used to correct errors caused by skew relative to a target path (hereinafter referred to as the target path) of the head 15, which is arranged concentrically with the disk 10, such as the center of the track. For ease of explanation, errors caused by skew relative to the target path due to RRO will be referred to as RRO. For example, the postamble is included in a normal servo sector. Alternatively, the postamble can be included in a short servo sector. The supplemental pattern is included in the short servo sector. Alternatively, the supplemental pattern may be included in the normal servo sector. For example, the length of the postamble PCLX1 is longer than the length of the supplemental pattern ADL. The length ASL1 of the servo sector SVS1 is longer than the length ASL0 of the servo sector SVS0. Furthermore, the length of the postamble PCLX1 may be less than the length ADL of the supplemental pattern. Furthermore, the length ASL1 of the servo sector SVS1 may be less than the length ASL0 of the servo sector SVS0.

[0061] Figure 7 Schematic diagram showing an example of a servo sector SVS2 of the servo area SV.

[0062] exist Figure 7In the example shown, servo sector SVS2 of servo zone SV includes pre-segment servo sector ZSVS11. For example, servo sector SVS1 includes segment servo sector ZSVS11 of segment servo zone ZSV1 of track TRn. Servo sector SVS2 includes servo pattern SVP2. Servo pattern SVP2 consists of at least one servo data element, such as a preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X2. Post-code X2 may be the same as or different from post-code X1. In servo pattern SVP2, preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X2 are arranged in the order indicated in the direction of travel. For example, in servo pattern SVP2, preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X2 are arranged continuously in the order indicated in the direction of travel. Servo sector SVS2 may also not include additional pattern or post-code X2. exist Figure 7 1 shows the length ASL2 of servo sector SVS2 and the length PCLX2 of post-code X2. The length ASL2 of servo sector SVS2 is, for example, greater than the length ASL0 of servo sector SVS0 and the length ASL1 of servo sector SVS1. The length PCLX2 of post-code X2 can be, for example, the same as the length PCLX1 of post-code X1, smaller than the length PCLX1 of post-code X1, or greater than the length PCLX1.

[0063] Figure 8 Schematic diagram showing an example of a servo sector SVS3 of the servo area SV.

[0064] exist Figure 8 In the example shown, servo sector SVS3 of servo zone SV includes post-segment servo sectors ZSVS21 and ZSVS22. For example, servo sector SVS3 includes segment servo sector ZSVS21 of segment servo zone ZSV2 of track TRn and segment servo sector ZSVS22 of segment servo zone ZSV2 of track TRm. Servo sector SVS3 includes servo pattern SVP3. Servo pattern SVP3 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, and a postamble X3. Postamble X3 can be the same as or different from postamble X1 or postamble X2. In servo pattern SVP3, the preamble, servo mark, Gray code, PAD, burst data, and postamble X3 are arranged in the order listed in the direction of travel. For example, in the servo pattern SVP3, the preamble, servo mark, Gray code, PAD, burst data, and post-code X3 are arranged continuously in the order of these descriptions in the direction of travel. In addition, the servo sector SVS3 may not include the post-code X3. Figure 81 shows the length ASL3 of servo sector SVS3 and the length PCLX3 of post-code X3. The length ASL3 of servo sector SVS3 can be, for example, the same as the length ASL0 of servo sector SVS0, or can be larger than or smaller than length ASL0. The length ASL3 of servo sector SVS3 can be, for example, the same as the length ASL1 of servo sector SVS1, or can be larger than or smaller than length ASL1. The length ASL3 of servo sector SVS3 can be, for example, the same as the length ASL2 of servo sector SVS2, or can be larger than or smaller than length ASL2. The length PCLX3 of post-code X3 can be, for example, the same as the length PCLX1 of post-code X1 or the length PCLX2 of post-code X2, or can be smaller than or larger than length PCLX1 or length PCLX2.

[0065] Figure 9 Schematic diagram showing an example of a servo sector SVS4 of the servo area SV.

[0066] exist Figure 9 In the example shown, servo sector SVS4 of servo zone SV includes post-segment servo sectors ZSVS21 and ZSVS22. For example, servo sector SVS4 includes segment servo sector ZSVS21 of segment servo zone ZSV2 of track TRn and segment servo sector ZSVS22 of segment servo zone ZSV2 of track TRm. Servo sector SVS4 includes servo pattern SVP4. Servo pattern SVP4 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, an additional pattern, and a postamble X4. Postamble X4 can be the same as or different from postamble X1, postamble X2, or postamble X3. In servo pattern SVP4, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and postamble X4 are arranged in the order listed in the direction of travel. For example, in the servo pattern SVP4, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X4 are arranged continuously in the order of these records in the direction of travel. In addition, the servo sector SVS4 may not include the additional pattern and post-code X4. Figure 94 shows the length ASL4 of servo sector SVS4 and the length PCLX4 of post-code X4. The length ASL4 of servo sector SVS4 is, for example, greater than the length ASL3 of servo sector SVS3. The length ASL4 of servo sector SVS4 can be the same as the length ASL2 of servo sector SVS2, or can be greater than or smaller than the length ASL2. The length PCLX4 of post-code X4 can be the same as the length PCLX1 of post-code X1, the length PCLX2 of post-code X2, or the length PCLX3 of post-code X3, or can be smaller than the length PCLX1, the length PCLX2, or the length PCLX3, or can be greater than the length PCLX1, the length PCLX2, or the length PCLX3.

[0067] Figure 10 Schematic diagram showing an example of a servo sector SVS5 of the servo area SV.

[0068] exist Figure 10 In the example shown, servo sector SVS5 of servo zone SV includes pre-segment servo sector ZSVS31. For example, servo sector SVS5 includes segment servo sector ZSVS31 of segment servo zone ZSV3 of track TRm. Servo sector SVS5 includes servo pattern SVP5. Servo pattern SVP5 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, and a postamble X5. Postamble X5 can be the same as or different from postamble X1, postamble X2, postamble X3, or postamble X4. In servo pattern SVP5, preamble, servo mark, Gray code, PAD, burst data, and postamble X5 are arranged in the order listed in the direction of travel. For example, in servo pattern SVP5, preamble, servo mark, Gray code, PAD, burst data, and postamble X5 are arranged continuously in the order listed in the direction of travel. In addition, the servo sector SVS5 may not include the post-code X5. Figure 10 1 and 2 show the length ASL5 of servo sector SVS5 and the length PCLX5 of post-code X5. The length ASL5 of servo sector SVS5 can be, for example, the same as the length ASL1 of servo sector SVS1 or the length ASL3 of servo sector SVS3, or can be larger or smaller than the lengths ASL1 or ASL3. The length PCLX5 of post-code X5 can be, for example, the same as the length PCLX1 of post-code X1, the length PCLX2 of post-code X2, the length PCLX3 of post-code X3, or the length PCLX4 of post-code X4, or can be smaller or larger than the lengths PCLX1, PCLX2, PCLX3, or PCLX4.

[0069] Figure 11 Schematic diagram showing an example of the servo sector SVS6 of the servo area SV.

[0070] exist Figure 11 In the example shown, servo sector SVS6 of servo area SV includes pre-segment servo sector ZSVS31. For example, servo sector SVS6 includes segment servo sector ZSVS31 of segment servo area ZSV3 of track TRm. Servo sector SVS6 includes servo pattern SVP6. Servo pattern SVP6 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, an additional pattern, and a postamble X6. Postamble X6 can be the same as or different from postamble X1, postamble X2, postamble X3, postamble X4, or postamble X5. In servo pattern SVP6, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and postamble X6 are arranged in the order indicated in the direction of travel. For example, in the servo pattern SVP6, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X6 are arranged continuously in the order of these records in the direction of travel. In addition, the servo sector SVS6 may not include the additional pattern and post-code X6. Figure 11 Length ASL6 of servo sector SVS6 is shown in FIG. Length ASL6 of servo sector SVS6 is, for example, greater than length ASL5 of servo sector SVS5. Length ASL6 of servo sector SVS6 can be the same as length ASL2 of servo sector SVS2 or length ASL4 of servo sector SVS4, or can be greater than length ASL2 or length ASL4, or can be smaller than length ASL2 or length ASL4. Length PCLX6 of post-code X6 can be the same as length PCLX1 of post-code X1, length PCLX2 of post-code X2, length PCLX3 of post-code X3, length PCLX4 of post-code X4, or length PCLX5 of post-code X5, or can be smaller than length PCLX1, length PCLX2, length PCLX3, length PCLX4, or length PCLX5, or can be greater than length PCLX1, length PCLX2, length PCLX3, length PCLX4, or length PCLX5.

[0071] Figure 12 Schematic diagram showing an example of a servo sector SVS7 of the servo area SV.

[0072] exist Figure 12In the example shown, servo sector SVS7 of servo zone SV includes the segment servo sectors outside the segment servo boundaries ZB of segment servo zones ZSV1, ZSV2, and ZSV3. For example, servo sector SVS7 includes the segment servo sectors of segment servo zone ZSV1 of track TRz1, the segment servo sectors of segment servo zone ZSV2 of track TRz2, and the segment servo sectors of segment servo zone ZSV3 of track TRz3. Servo sector SVS7 includes a servo pattern SVP7. Servo pattern SVP7 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, and a post-code X7. Post-code X7 can be the same as or different from post-code X1, post-code X2, post-code X3, post-code X4, post-code X5, or post-code X6. In the servo pattern SVP7, the preamble, servo mark, Gray code, PAD, burst data, and post-code X7 are arranged in the order of these descriptions in the direction of travel. For example, in the servo pattern SVP7, the preamble, servo mark, Gray code, PAD, burst data, and post-code X7 are arranged continuously in the order of these descriptions in the direction of travel. In addition, the servo sector SVS7 may not include the post-code X7. Figure 12 Length ASL7 of servo sector SVS7 and length PCLX7 of post-code X7 are shown in FIG. Length ASL7 of servo sector SVS7 may be the same as length ASL1 of servo sector SVS1, length ASL3 of servo sector SVS3, or length ASL5 of servo sector SVS5, or may be greater than length ASL1, length ASL3, or length ASL5, or may be less than length ASL1, length ASL3, or length ASL5. The length PCLX7 of the post-code X7 can be, for example, the same as the length PCLX1 of the post-code X1, the length PCLX2 of the post-code X2, the length PCLX3 of the post-code X3, the length PCLX4 of the post-code X4, the length PCLX5 of the post-code X5, or the length PCLX6 of the post-code X6. It can also be smaller than the length PCLX1, the length PCLX2, the length PCLX3, the length PCLX4, the length PCLX5, or the length PCLX6. It can also be larger than the length PCLX1, the length PCLX2, the length PCLX3, the length PCLX4, the length PCLX5, or the length PCLX6.

[0073] Figure 13 Schematic diagram showing an example of a servo sector SVS8 of the servo area SV.

[0074] exist Figure 13In the example shown, servo sector SVS8 of servo zone SV includes the segment servo sectors outside the segment servo boundaries ZB of segment servo zones ZSV1, ZSV2, and ZSV3. For example, servo sector SVS8 includes the segment servo sectors of segment servo zone ZSV1 of track TRz1, the segment servo sectors of segment servo zone ZSV2 of track TRz2, and the segment servo sectors of segment servo zone ZSV3 of track TRz3. Servo sector SVS8 includes a servo pattern SVP8. Servo pattern SVP8 consists of at least one servo data element, such as a preamble, a servo mark, a Gray code, a PAD, burst data, an additional pattern, and a post-code X8. Post-code X8 can be the same as or different from post-code X1, post-code X2, post-code X3, post-code X4, post-code X5, post-code X6, or post-code X7. In the servo pattern SVP8, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X8 are arranged in the order of these records in the direction of travel. For example, in the servo pattern SVP8, the preamble, servo mark, Gray code, PAD, burst data, additional pattern, and post-code X8 are arranged continuously in the order of these records in the direction of travel. In addition, the servo sector SVS8 may not include the additional pattern and post-code X8. Figure 13 Length ASL8 of servo sector SVS8 is shown in FIG. Length ASL8 of servo sector SVS8 is, for example, greater than length ASL7 of servo sector SVS7. Length ASL8 of servo sector SVS8 may be the same as length ASL2 of servo sector SVS2, length ASL4 of servo sector SVS4, or length ASL6 of servo sector SVS6, or may be greater than length ASL2, length ASL4, or length ASL6, or may be less than length ASL2, length ASL4, or length ASL6. The length PCLX8 of the post-code X8 can be, for example, the same as the length PCLX1 of the post-code X1, the length PCLX2 of the post-code X2, the length PCLX3 of the post-code X3, the length PCLX4 of the post-code X4, the length PCLX5 of the post-code X5, the length PCLX6 of the post-code X6 or the length PCLX7 of the post-code X7, or it can be smaller than the length PCLX1, length PCLX2, length PCLX3, length PCLX4, length PCLX5, length PCLX6 or length PCLX7, or it can be larger than the length PCLX1, length PCLX2, length PCLX3, length PCLX4, length PCLX5, length PCLX6 or length PCLX7.

[0075] The driver IC 20 controls driving of the SPM 12 and the VCM 14 in accordance with control of the system controller 130 (more specifically, the MPU 60 described later).

[0076] The head amplifier IC (preamplifier) ​​30 includes a read amplifier and a write driver. The read amplifier amplifies the read signal from the disk 10 and outputs it to the system controller 130 (specifically, the read / write (R / W) channel 40 described later). The write driver outputs a write current to the head 15 in response to the signal output from the R / W channel 40.

[0077] Volatile memory 70 is a semiconductor memory that loses stored data if power is cut off. It stores data required for processing in various components of magnetic disk drive 1. Examples of volatile memory 70 include DRAM (Dynamic Random Access Memory) and SDRAM (Synchronous Dynamic Random Access Memory).

[0078] The nonvolatile memory 80 is a semiconductor memory that records stored data even when power is cut off. The nonvolatile memory 80 is, for example, a NOR-type or NAND-type flash ROM (Flash Read Only Memory: FROM).

[0079] The buffer memory 90 is a semiconductor memory that temporarily stores data exchanged between the magnetic disk drive 1 and the host computer 100. Alternatively, the buffer memory 90 may be integrally formed with the volatile memory 70. Examples of the buffer memory 90 include DRAM, SRAM (Static Random Access Memory), SDRAM, FeRAM (Ferroelectric Random Access Memory), and MRAM (Magnetoresistive Random Access Memory).

[0080] The system controller (controller) 130 is 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 read / write (R / W) channel 40, a hard disk controller (HDC) 50, and a microprocessor (MPU) 60. The system controller 130 is electrically connected to, for example, a driver IC 20, a head amplifier IC 30, a volatile memory 70, a nonvolatile memory 80, a buffer memory 90, and a host computer 100.

[0081] The R / W channel 40 performs signal processing, such as modulation, demodulation, encoding, and decoding, for data read from the disk 10 to the host 100 and data written from the host 100, based on instructions from the MPU 60, described later. The R / W channel 40 includes circuitry or functions for measuring the signal quality of read data. The R / W channel 40 detects various strobes, such as a write strobe corresponding to a signal for writing data, a read strobe corresponding to a signal for reading data, and a servo strobe corresponding to a signal for reading a servo. The R / W channel 40 performs signal processing for write data based on the write strobe, signal processing for read data based on the read strobe, and signal processing for servo data based on the servo strobe. The R / W channel 40 performs servo read processing, demodulating servo data based on a read signal input from the head amplifier IC 30, and writes data to the disk 10 (outputting write data to the head amplifier IC 30). The R / W channel 40 performs servo read processing and reads data from the disk 10. The R / W channel 40 is electrically connected to, for example, the head amplifier IC 30 , the HDC 50 , and the MPU 60 .

[0082] For example, the R / W channel 40 servo-reads servo sectors in a predetermined area of ​​the disk 10 based on a servo gate that servo-reads servo data from the servo sectors as a whole, and writes data to the area based on the servo data servo-read based on the servo gate. Hereinafter, the "servo gate that servo-reads servo data from the servo sectors as a whole" may be referred to as a "normal servo gate." The "servo read process performed based on the normal servo gate" may also be referred to as "normal servo read" or "normal servo read process."

[0083] For example, the R / W channel 40 servo-reads a portion of the servo data of a servo sector in a predetermined area of ​​the disk 10, for example, a servo gate that servo-reads a circumferential range smaller than the circumferential range of the servo data servo-read by a normal servo gate, and performs a write process on the area based on the servo data servo-read by the servo gate. Hereinafter, "a servo gate that servo-reads a portion of the servo data of a servo sector, for example, a circumferential range smaller than the circumferential range of the servo data servo-read by a normal servo gate" may be referred to as a "short servo gate." "Performing a servo read process based on a short servo gate" may also be referred to as "short servo read" or "short servo read process." The length of time from when a normal servo gate becomes active (active, valid, or ON) to when it becomes inactive (inactive, invalid, or OFF) differs between a normal servo gate and a short servo gate (hereinafter also referred to as a servo gate length). For example, the servo gate length of the normal servo gate is longer than the servo gate length of the short servo gate.

[0084] For example, the R / W channel 40 performs normal servo reading of a servo sector in a predetermined area of ​​the disk 10 and executes a read process to the area based on servo data read by the normal servo.

[0085] For example, the R / W channel 40 may perform short servo reading on a servo sector in a predetermined area of ​​the disk 10 and execute a read process on the area based on the servo data obtained by the short servo reading.

[0086] The R / W channel 40 performs normal servo read processing in a predetermined area of ​​the disk 10. Furthermore, the R / W channel 40 may be able to switch between performing or not performing short servo read processing in a predetermined area of ​​the disk 10. The "mode in which the short servo read processing is performed" is sometimes referred to as the "Short Servo Mode." Furthermore, "performing the short servo read processing" is sometimes referred to as "turning the short servo mode on," and "not performing the short servo read processing" is sometimes referred to as "turning the short servo mode off." In other words, the R / W channel 40 can switch the short servo mode on and off. For example, the R / W channel 40 may switch the short servo mode on and off depending on whether the mode is for performing a write process (hereinafter referred to as the write mode) or a read process (hereinafter referred to as the read mode). Hereinafter, the "write mode" and "read mode" are sometimes collectively referred to as the "access mode." The term "access" includes the following meanings: "recording or writing data to a predetermined area of ​​the disk 10," "reading or reading data from a predetermined area of ​​the disk 10," "moving the head 15, etc. to a predetermined area of ​​the disk 10," etc. In other words, the R / W channel 40 can also switch the short servo pattern on and off according to the access mode.

[0087] The HDC 50 controls data transfer between the host 100 and the R / W channel 40 based on instructions from the MPU 60, described later. Based on instructions from the MPU 60, described later, the HDC 50 outputs various strobes, such as a write strobe, a read strobe, and a servo strobe, to the R / W channel 40. For example, the HDC 50 generates a normal servo strobe and outputs it to the R / W channel 40. A normal servo strobe is, for example, a strobe for reading at least a preamble, servo marks, Gray code, PAD, and burst data. For example, the HDC 50 generates a short servo strobe and outputs it to the R / W channel 40. A short servo strobe is a strobe for reading at least burst data without reading at least a preamble, servo marks, Gray code, PAD, and burst data. The HDC 50 is electrically connected to, for example, the R / W channel 40, the MPU 60, the volatile memory 70, the non-volatile memory 80, and the buffer memory 90.

[0088] The MPU 60 is the main controller that controls various components of the magnetic disk drive 1. The MPU 60 controls the VCM 14 via the driver IC 20, performing servo control to position the head 15. Furthermore, the MPU 60 controls the SPM 12 via the driver IC 20 to rotate the disk 10. The MPU 60 controls writing data to the disk 10 and selects the storage destination for written data. Furthermore, the MPU 60 controls reading data from the disk 10 and controls the processing of read data. Furthermore, the MPU 60 manages the area where data is recorded. The MPU 60 is connected to various components of the magnetic disk drive 1. For example, the MPU 60 is electrically connected to the driver IC 20, the R / W channel 40, and the HDC 50.

[0089] Figure 14 This is a schematic diagram showing an example of the configuration of the system controller 130 according to this embodiment.

[0090] The R / W channel 40 includes a strobe detection unit 410. The strobe detection unit 410 detects whether various strobes, such as the write strobe, read strobe, and servo strobe, are active or inactive. For example, the strobe detection unit 410 executes a write process if it detects that the write strobe is active, and stops the write process if it detects that the write strobe is negative. The strobe detection unit 410 executes a read process if it detects that the read strobe is active, and stops the read process if it detects that the read strobe is negative. The strobe detection unit 410 executes a servo read process if it detects that the servo strobe is active, and stops the servo read process if it detects that the servo strobe is negative. Alternatively, the strobe detection unit 410 may be located within the HDC 50 or the MPU 60.

[0091] The HDC 50 includes a strobe generator 510. Based on commands from the host 100 or instructions from the MPU 60, the strobe generator 510 generates various strobes, such as a write strobe, a read strobe, and a servo strobe, and outputs them to the R / W channel 40, for example, the strobe detector 410. Hereinafter, "starting a predetermined strobe" may be referred to as "activating a predetermined strobe." Furthermore, "deactivating a predetermined strobe" may be referred to as "negating a predetermined strobe." The terms "activating a predetermined strobe" and "negating a predetermined strobe" may also include "generating a predetermined strobe." Furthermore, the strobe generator 510 may also be included in the R / W channel 40 or the MPU 60.

[0092] For example, the gate generation unit 510 generates a common servo gate and outputs the common servo gate to the gate detection unit 410. For example, the gate generation unit 510 generates a plurality of common servo gates and outputs the plurality of common servo gates to the gate detection unit 410.

[0093] For example, when the short servo mode is on, the gate generation unit 510 generates a normal servo gate and a short servo gate, and outputs the normal servo gate and the short servo gate to the gate detection unit 410 .

[0094] For example, when the short servo pattern is OFF, the gate generation unit 510 generates a normal servo gate and outputs the normal servo gate to the gate detection unit 410. For example, when the short servo pattern is OFF, the gate generation unit 510 generates multiple normal servo gates and outputs the multiple normal servo gates to the gate detection unit 410.

[0095] Figure 15 This is a diagram showing an example of normal servo readout processing. Figure 15 A normal servo sector NSV1 is shown in FIG. Figure 15 , which demodulates all servo data written in the normal servo sector NSV1, is shown in FIG. Figure 15 In the embodiment, the normal servo gate is activated at the start timing T151 corresponding to the leading end of the preamble, and is negated at the end timing T152 corresponding to the trailing end of the postamble.

[0096] The selection detection unit 410 activates the normal servo selection at the start timing T151 and starts the servo reading of the normal servo sector NSV1, reads and demodulates in the order of servo mark, Gray code, PAD, N burst, Q burst and post-code, and ends the servo reading of the normal servo sector NSV1 at the end timing T152 when the post-code is read.

[0097] Figure 16 FIG. 1 is a diagram showing an example of a normal servo readout process. Figure 16 The normal servo sector NSV2 is shown in FIG. Figure 16 , which demodulates all servo data of the normal servo sector NSV2, is shown in FIG. Figure 16 In the example, the normal servo gate is activated at a start timing T161 corresponding to the leading end of the preamble, and is negated at an end timing T162 corresponding to the trailing end of the postamble.

[0098] The selection detection unit 410 activates the normal servo selection at the start timing T161 and starts the servo readout of the normal servo sector NSV2, reads and demodulates in the order of servo mark, Gray code, PAD, N burst, Q burst, additional pattern and post-code, and ends the servo readout of the normal servo sector NSV2 at the end timing T162 when the post-code is read.

[0099] Figure 17 : is a diagram showing an example of short servo processing. Figure 17 The short servo sector SSV is shown in FIG. Figure 17, which demodulates the burst data and additional pattern of the short servo sector SSV. Figure 17 In FIG. 1 , the short servo gate is activated at a start timing T171 corresponding to the leading end of the N burst, and is negated at a timing T172 corresponding to the trailing end of the additional pattern.

[0100] The selection detection unit 410 activates the short servo selection at the start timing T171 based on the leading code, servo mark and Gray code of the normal servo sector just read out, and starts the servo reading of the short servo sector SSV. It reads and demodulates in the order of N burst, Q burst and additional pattern, and ends the servo reading of the short servo sector SSV at the end timing T172 when the additional pattern is read out.

[0101] The MPU 60 includes a read / write control unit 610 and a servo pattern management unit 620. The MPU 60 executes the processing of each unit, such as the read / write control unit 610 and the servo pattern management unit 620, in firmware. Alternatively, the MPU 60 may include each unit, such as the read / write control unit 610 and the servo pattern management unit 620, as a circuit. The read / write control unit 610 and the servo pattern management unit 620 may also be included in the R / W channel 40 or the HDC 50.

[0102] The read / write control unit 610 controls the reading process of data from the disk 10 and the writing process of data to the disk 10 in accordance with commands from the host 100. The read / write control unit 610 controls the VCM 14 via the driver IC 20 to position the head 15 at a predetermined position on the disk 10 and perform the reading process or the writing process.

[0103] The read / write control unit 610 performs a write process in a conventional magnetic recording (CMR) format, for example, to write (or read) data to another track (hereinafter referred to as an adjacent track) or another sector (hereinafter referred to as an adjacent sector) that is adjacent to a predetermined track or sector at a predetermined interval (gap) in the radial direction. "Adjacent tracks" include "tracks adjacent in the outer direction of a predetermined track," "tracks adjacent in the inner direction of a predetermined track," and "a plurality of tracks adjacent in both the outer and inner directions of a predetermined track." "Adjacent sectors" include "sectors adjacent in the outer direction of a predetermined sector," "sectors adjacent in the inner direction of a predetermined sector," and "a plurality of sectors adjacent in both the outer and inner directions of a predetermined sector." Hereinafter, "writing data in a conventional recording format" may be referred to as "normal recording," "performing a conventional recording process," or simply "writing."

[0104] Furthermore, the read / write control unit 610 performs a write process using shingled write magnetic recording (SMR or SWR), which overlaps a previously written track with a radial portion of the previously written track when sequentially writing to multiple tracks. Hereinafter, "writing data using the shingled recording method" may be referred to as "shingled recording," "performing the shingled recording process," or simply "writing."

[0105] The read / write control unit 610 performs normal recording processing or shingled recording processing according to commands from the host 100. The read / write control unit 610 performs write processing in a recording mode that selects normal recording processing and shingled recording processing (hereinafter, this may also be referred to as a hybrid recording mode) according to commands from the host 100. Hereinafter, "writing data in a hybrid recording mode" may be referred to as "hybrid recording" or "performing a hybrid recording process" or simply "writing". In addition, the read / write control unit 610 may be configured to perform only normal recording processing or only shingled recording processing.

[0106] For example, the read / write control unit 610 performs only normal recording processing in areas with low format efficiency. For example, the read / write control unit 610 performs only normal recording processing within the zone servo boundary ZB. In other words, the read / write control unit 610 does not perform hybrid recording processing within the zone servo boundary ZB.

[0107] For example, the read / write control unit 610 performs only the shingled recording process in areas with low format efficiency. For example, the read / write control unit 610 performs only the shingled recording process within the zone servo boundaries ZB. In other words, the read / write control unit 610 does not perform the hybrid recording process within the zone servo boundaries ZB.

[0108] Figure 18 This is a schematic diagram showing an example of normal recording processing. Figure 18 Tracks CTR1, CTR2, and CTR3 are shown in FIG. Figure 18 For example, the track widths of tracks CTR1, CTR2, and CTR3 are the same. In addition, the track widths of tracks CTR1 to CTR3 may be different. Figure 18 1 shows the track center CTC1 of the track CTR1, the track center CTC2 of the track CTR2, and the track center CTC3 of the track CTR3. Figure 18In the example shown, tracks CTR1 and CTR2 are written with a track pitch CTP. Tracks CTR2 and CTR3 are written with a track pitch CTP. The track center CTC1 of track CTR1 and the track center CTC2 of track CTR2 are separated by the track pitch CTP. The track center CTC2 of track CTR2 and the track center CTC3 of track CTR3 are separated by the track pitch CTP. The track pitch between tracks CTR1 and CTR2 and the track pitch between tracks CTR2 and CTR3 may be the same or different. Track CTR1 and track CTR2 are separated by a gap CGP. Track CTR2 and track CTR3 are separated by a gap CGP. The gap between tracks CTR1 and CTR2 and the gap between tracks CTR2 and CTR3 may be the same or different. In Figure 18 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 reality, it is curved along the circumferential direction. In addition, each track can also be a wave shape extending in the circumferential direction while changing in the radial direction.

[0109] exist Figure 18 In the illustrated example, the read / write control unit 610 positions the head 15 at the track center CTC1 in a predetermined area of ​​the disk 10, for example, the user data area 10a, and performs normal recording on track CTR1 or a predetermined sector of track CTR1. The read / write control unit 610 positions the head 15 at the track center CTC2, which is separated inward from the track center CTC1 of track CTR1 by the track pitch CTP in the user data area 10a, and performs normal recording on track CTR2 or a predetermined sector of track CTR2.

[0110] The read / write control unit 610 positions the head 15 at the track center CTC3 separated from the track center CTC2 of the track CTR2 inward by the track pitch CTP in the user data area 10a and performs normal recording on the track CTR3 or a predetermined sector of the track CTR3.

[0111] The read / write control unit 610 can normally record tracks CTR1, CTR2 and CTR3 sequentially in a predetermined area of ​​the disk 10, for example, in the user data area 10a, or can normally record randomly in a predetermined sector of track CTR1, a predetermined sector of track CTR2 and a predetermined sector of track CTR3.

[0112] Figure 19 Schematic diagram showing an example of shingled recording processing. Figure 19The forward direction is shown in . There is also a case where a plurality of tracks are continuously recorded in a radial direction in a shingled manner, that is, the direction in which the track written next overlaps the track written previously in the radial direction is called the forward direction. Figure 19 In the example, the inner direction is set as the forward direction in the radial direction, but the outer direction can also be set as the forward direction in the radial direction. Figure 19 In FIG, a plurality of tracks STR1, STR2, and STR3 are shown that are overlapped and written continuously in one direction in the radial direction. Hereinafter, in shingled recording, there is also a case where the area where data is written by the write head 15W is referred to as a write track, and the remaining area other than the area where other write tracks are overlapped and written in a predetermined track is referred to as a read track. Figure 19 The track center STC1 of track STR1 when not being overlapped with other tracks, the track center STC2 of track STR2 when not being overlapped with other tracks, and the track center STC3 of track STR3 when not being overlapped with other tracks are shown in FIG. Figure 19 In the example shown, tracks STR1 and STR2 are written with a track pitch STP. Tracks STR2 and STR3 are written with a track pitch STP. The track center STC1 of track (or write track) STR1 and the track center STC2 of track (or write track) STR2 are separated by a track pitch STP. The track center STC2 of track STR2 and the track center STC3 of track STR3 are separated by a track pitch STP. The track pitch between tracks STR1 and STR2 and the track pitch between tracks STR2 and STR3 may be the same or different. Figure 19 In the embodiment, the radial width of the area (read track) in track STR1 where track STR2 is not overlapped and the radial width of the area (read track) in track STR2 where track STR3 is not overlapped and written are the same. In addition, the radial width of the area (read track) in track STR1 where track STR2 is not overlapped and the radial width of the area (read track) in track STR2 where track STR3 is not overlapped and written are different. Figure 4 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 reality, it is curved along the circumferential direction. In addition, each track can also be a wave shape extending in the circumferential direction while changing in the radial direction. In addition, in Figure 19 In the example, overlapping writing is performed on three tracks, but overlapping writing can also be performed on less than three or more than three tracks.

[0113] exist Figure 19In the example shown, the read / write control unit 610 sequentially performs shingled recording on the tracks STR1 to STR3 in the inward direction. In addition, the read / write control unit 610 may also sequentially perform shingled recording on the tracks STR1 to STR3 in the outward direction. The read / write control unit 610 writes to the track STR2 at the track pitch STP in the inward direction of the track STR1, and performs overlapping writing on the track STR2 with respect to a portion of the inward direction of the track STR1. The read / write control unit 610 writes to the track STR3 at the track pitch STP in the inward direction of the track STR2, and performs overlapping writing on the track STR3 with respect to a portion of the inward direction of the track STR2. In addition, the read / write control unit 610 may also write to the track STR2 at the track pitch STP in the outward direction of the track STR1, and performs overlapping writing on the track STR2 with respect to a portion of the inward direction of the track STR1. The read / write control unit 610 may write to the track STR3 at the track pitch STP in the outer direction of the track STR2 and perform overlapping writing on the track STR3 relative to a portion of the inner direction of the track STR2.

[0114] The servo pattern management unit 620 manages servo patterns (or servo data). The servo pattern management unit 620 writes servo patterns (or servo data) to the disk 10. Hereinafter, "writing a servo pattern" or "arranging a servo pattern" may also be referred to as "servo writing." For example, the servo pattern management unit 620 writes a servo pattern (or servo data) to the disk 10 using self-servo writing (SSW) based on a base servo pattern (or servo data).

[0115] The servo pattern management unit 620 writes a different servo pattern (or servo data) to each predetermined area. The servo pattern management unit 620 writes a servo pattern including a different post-code to each predetermined area. The servo pattern management unit 620 writes a servo pattern including a predetermined post-code to each predetermined area. The servo pattern management unit 620 writes a different post-code to each predetermined area. The servo pattern management unit 620 writes a predetermined post-code to each predetermined area. The servo pattern management unit 620 writes a post-code to each predetermined area that has a lower format efficiency than the predetermined area, for example, a post-code of a shorter length than the post-code of the predetermined area, to improve the format efficiency.

[0116] For example, the servo pattern management unit 620 writes a servo pattern (or servo data) including a postcode corresponding to a writing method (e.g., a normal recording method, a shingled recording method, or a hybrid recording method) that improves (or improves) the format efficiency of a predetermined area into the area. For example, the servo pattern management unit 620 writes a postcode corresponding to a writing method that improves (or improves) the format efficiency of the predetermined area into the area.

[0117] For example, the servo pattern management unit 620 writes a servo pattern (or servo data) including a post-code corresponding to a writing pattern that maximizes (or improves) the format efficiency of a predetermined area into the area. For example, the servo pattern management unit 620 writes a post-code corresponding to a writing pattern that maximizes (or improves) the format efficiency of a predetermined area into the area.

[0118] The servo pattern management unit 620 sets a different write pattern for each predetermined area and writes a servo pattern including a post-code corresponding to the set write pattern into each predetermined area. The servo pattern management unit 620 sets a predetermined write pattern for each predetermined area and writes a servo pattern including a post-code corresponding to the set write pattern into each predetermined area. The servo pattern management unit 620 sets a different write pattern for each predetermined area and writes a post-code corresponding to the set write pattern into each predetermined area. The servo pattern management unit 620 sets a predetermined write pattern for each predetermined area and writes a post-code corresponding to the set write pattern into each predetermined area.

[0119] For example, the servo pattern management unit 620 sets a write pattern that increases (or improves) the format efficiency of a predetermined area in the area, and writes a servo pattern (hereinafter referred to as a high format efficiency pattern) that includes a post-code that increases (or improves) the format efficiency of the area (hereinafter referred to as a high format efficiency code) from among the multiple post-codes corresponding to the set write pattern into the area. For example, the servo pattern management unit 620 sets a write pattern that increases (or improves) the format efficiency of the predetermined area, and writes a high format efficiency code that increases (or improves) the format efficiency of the area from among the multiple post-codes corresponding to the set write pattern into the area. For example, the high format efficiency code corresponds to a post-code that is shorter than the post-codes in other areas.

[0120] For example, the servo pattern management unit 620 sets a write pattern that increases (or improves) the format efficiency of a predetermined area, and writes a servo pattern (hereinafter referred to as a highest format efficiency pattern) including a post-code that increases (or improves) the format efficiency of the area to the greatest extent among the multiple post-codes corresponding to the set write pattern (hereinafter referred to as a highest format efficiency code). For example, the servo pattern management unit 620 sets a write pattern that increases (or improves) the format efficiency of a predetermined area, and writes a highest format efficiency code that increases (or improves) the format efficiency of the area to the area among the multiple post-codes corresponding to the set write pattern. For example, the highest format efficiency code corresponds to the post-code with the shortest length among the multiple post-codes.

[0121] The servo pattern management unit 620 sets a region to be written using a different writing pattern for each predetermined region, and writes a servo pattern including a post-amble corresponding to the writing pattern into each predetermined region. The servo pattern management unit 620 sets a region to be written using a predetermined writing pattern for each predetermined region, and writes a servo pattern including a post-amble corresponding to the writing pattern into each predetermined region. The servo pattern management unit 620 sets a region to be written using a different writing pattern for each predetermined region, and writes a post-amble corresponding to the writing pattern into each predetermined region. The servo pattern management unit 620 sets a region to be written using a predetermined writing pattern for each predetermined region, and writes a post-amble corresponding to the writing pattern into each predetermined region.

[0122] For example, the servo pattern management unit 620 sets a predetermined area for writing using a writing pattern that increases (or improves) the format efficiency, and writes a servo pattern (hereinafter referred to as a high format efficiency pattern) including a post-code that increases (or improves) the format efficiency of the region (hereinafter referred to as a high format efficiency code) from among a plurality of post-codes corresponding to the writing pattern of the region into the predetermined area. For example, the servo pattern management unit 620 sets a predetermined area for writing using a writing pattern that increases (or improves) the format efficiency, and writes a high format efficiency code that increases (or improves) the format efficiency of the region from among a plurality of post-codes corresponding to the writing pattern of the region into the predetermined area.

[0123] For example, the servo pattern management unit 620 sets the area to be written using a writing pattern that increases (or improves) the format efficiency of the predetermined area as a predetermined area, and writes the highest format efficiency pattern, which includes the highest format efficiency code that increases (or improves) the format efficiency of the area to the greatest extent among the multiple post codes corresponding to the writing pattern of the area, into the area. For example, the servo pattern management unit 620 sets the area to be written using a writing pattern that increases (or improves) the format efficiency of the predetermined area as a predetermined area, and writes the highest format efficiency code that increases (or improves) the format efficiency of the area to the area among the multiple post codes corresponding to the writing pattern of the area.

[0124] For example, the servo pattern management unit 620 stores a servo pattern (hereinafter referred to as a servo pattern for a normal recording mode) including a post-code when data is written in a normal recording mode (hereinafter referred to as a post-code for a normal recording mode), a servo pattern (hereinafter referred to as a servo pattern for a shingled recording mode) including a post-code when data is written in a shingled recording mode (hereinafter referred to as a post-code for a shingled recording mode), and a servo pattern (hereinafter referred to as a servo pattern for a hybrid recording mode) including a post-code when data is written by selecting the normal recording mode and the shingled recording mode (hereinafter referred to as a post-code for a hybrid recording mode) in a predetermined recording area, such as the disk 10 or the nonvolatile memory 80. Furthermore, the servo pattern management unit 620 may store at least one of the servo pattern for a normal recording mode, the servo pattern for a shingled recording mode, and the servo pattern for a hybrid recording mode.

[0125] For example, the servo pattern management unit 620 sets an area to be written using a writing mode that improves (or improves) the format efficiency among the normal recording mode, the shingled recording mode, and the hybrid recording mode as a predetermined area, and writes a plurality of post-codes corresponding to the writing mode of the area, for example, a high format efficiency pattern of a high format efficiency code that improves (or improves) the format efficiency of the area among the post-codes for the normal recording mode, the post-codes for the shingled recording mode, and the post-codes for the hybrid recording mode, into the area.

[0126] For example, the servo pattern management unit 620 sets the area to be written using a writing mode that improves (or enhances) the format efficiency among the normal recording mode, the shingled recording mode, and the hybrid recording mode as a predetermined area, and includes multiple post-codes corresponding to the writing mode of the area, for example, the highest format efficiency pattern of the highest format efficiency code that improves (or enhances) the format efficiency of the area among the post-codes for the normal recording mode, the post-codes for the shingled recording mode, and the post-codes for the hybrid recording mode is written into the area.

[0127] For example, the servo pattern management unit 620 stores the normal recording mode post-code, the shingled recording mode post-code, and the hybrid recording mode post-code in a predetermined recording area, such as the disk 10 or the nonvolatile memory 80. Furthermore, the servo pattern management unit 620 may store at least one of the normal recording mode post-code, the shingled recording mode post-code, and the hybrid recording mode post-code.

[0128] For example, the servo pattern management unit 620 sets an area to be written using a writing mode that improves (or enhances) the format efficiency among the normal recording mode, the shingled recording mode, and the hybrid recording mode as a predetermined area, and writes multiple post-codes corresponding to the writing mode of the area, for example, a high format efficiency code that improves (or enhances) the format efficiency of the area among the post-codes for the normal recording mode, the post-codes for the shingled recording mode, and the post-codes for the hybrid recording mode, into the area.

[0129] For example, the servo pattern management unit 620 sets an area to be written using a write mode that improves (or improves) the format efficiency of a predetermined area among the normal recording mode, the shingled recording mode, and the hybrid recording mode as a predetermined area, and writes multiple post-codes corresponding to the write mode of the area, for example, the highest format efficiency code that improves (or improves) the format efficiency of the area among the post-code for the normal recording mode, the post-code for the shingled recording mode, and the post-code for the hybrid recording mode, into the area.

[0130] The servo pattern management unit 620 sets the length of the segment servo gap based on the longest post-code among the multiple post-codes written to the forward segment servo sector, writes a post-code corresponding to a writing type that improves (or improves) the format efficiency of the segment data pattern to the forward segment servo sector, and writes a post-code corresponding to a writing type that improves (or improves) the format efficiency of the segment data pattern to the backward segment servo sector.

[0131] For example, the servo pattern management unit 620 sets a segment servo gap in which the front segment servo sector will not be covered by the rear segment servo sector even when the longest post-code among multiple post-codes is written into the front segment servo sector, writes a post-code corresponding to a writing type that improves (or improves) the format efficiency of the segment data pattern into the front segment servo sector, and writes a post-code corresponding to a writing type that improves (or improves) the format efficiency of the segment data pattern into the rear segment servo sector.

[0132] For example, the servo pattern management unit 620 sets the area to be written in the writing mode that improves (or improves) the format efficiency among the normal recording mode, the shingled recording mode and the hybrid recording mode as a predetermined segment data pattern, sets a segment servo gap in which the front segment servo sector will not be covered by the rear segment servo sector even when the longest post-code among multiple post-codes is written into the front segment servo sector, writes the post-code corresponding to the writing mode that improves (or improves) the format efficiency of the segment data pattern into the front segment servo sector, and writes the post-code corresponding to the writing mode that improves (or improves) the format efficiency of the segment data pattern into the rear segment servo sector.

[0133] The servo pattern management unit 620 sets the length of the segment servo gap based on the longest post-code among the multiple post-codes written to the forward segment servo sector, writes a post-code corresponding to a writing type that improves (or enhances) the format efficiency of the segment data pattern to the forward segment servo sector, and writes a predetermined post-code to the backward segment servo sector.

[0134] For example, the servo pattern management unit 620 sets a segment servo gap so that the front segment servo sector will not be covered by the rear segment servo sector even when the longest post-code among multiple post-codes is written into the front segment servo sector, sets the length of the segment servo gap, writes a post-code corresponding to a writing type that improves (or improves) the format efficiency of the segment data pattern into the front segment servo sector, and writes a predetermined post-code into the rear segment servo sector.

[0135] For example, the servo pattern management unit 620 sets the area to be written using a writing mode that improves (or enhances) the format efficiency among the normal recording mode, the shingled recording mode, and the hybrid recording mode as a predetermined segment data pattern, sets a segment servo gap in which the front segment servo sector will not be covered by the rear segment servo sector even when the longest post-code among multiple post-codes is written into the front segment servo sector, writes a post-code corresponding to the writing mode that improves (or enhances) the format efficiency of the segment data pattern into the front segment servo sector, and writes a predetermined post-code into the rear segment servo sector.

[0136] For example, the servo pattern management unit 620 selects a post-code having a shorter length than other post-codes from a plurality of post-codes in the sector data pattern and writes the post-code to the preceding sector servo sector.

[0137] Below, refer to Figure 20A 、 Figure 20B 、 Figure 21A 、 Figure 21B 、 Figure 22A 、 Figure 22B 、 Figure 23A 、 Figure 23B 、 Figure 24A 、 Figure 24B 、 Figure 25A 、 Figure 25B 、 Figure 26A and Figure 26B An example of a postcode corresponding to each writing pattern will be described.

[0138] Figure 20A This is a schematic diagram showing an example of the normal recording format post-code PC1 according to the present embodiment. Figure 20A 1 shows the length PCL1 of the postcode (or postcode) PC1 used in the normal recording format.

[0139] exist Figure 20AIn the example shown, the postcode PC1 for normal recording mode includes a postcode preamble (PostCodePreamble), a postcode synchronization mark (PostCodeSM) and a postcode data 1 (Postcodedata1). Figure 20A In the example shown, in the normal recording type post-code PC1, a post-code preamble (PostCode Preamble), a post-code synchronization mark (PostCode SM), and post-code data 1 (Postcode data 1) are arranged consecutively in the order listed in the direction of travel. The normal recording type post-code PC1 is a post-code arranged in a servo sector used in the write process of the normal recording area (hereinafter referred to as the normal recording area), which is not used in the short servo process. The normal recording type post-code PC1 includes post-code data used in the adjacent servo sector in the direction of travel (hereinafter referred to as the next post-code data). Hereinafter, the "servo sector adjacent in the direction of travel of a predetermined servo sector" may be referred to as the "next servo sector." The data length of the post-code data 1 (hereinafter referred to as the data length) is, for example, 15 bits.

[0140] The servo pattern management unit 620, for example, sets a predetermined area as a normal recording area and writes a normal recording type post-code PC1 into the normal servo sectors of the area. For example, the servo pattern management unit 620 sets the zone servo boundary ZB1 as the normal recording area and writes the normal recording type post-code PC1 as post-code X1 into the normal servo sector SVS1 within the zone servo boundary ZB1. For example, the servo pattern management unit 620 sets the zone servo boundary ZB2 as the normal recording area and writes the normal recording type post-code PC1 as post-code X5 into the normal servo sector SVS5 within the zone servo boundary ZB2. For example, the servo pattern management unit 620 sets the entire disk 10 as the normal recording area and writes the normal recording type post-code PC1 as post-codes X1, X3, X5, and X7 into the normal servo sectors SVS1, SVS3, SVS5, and SVS7, respectively, throughout the entire disk 10.

[0141] Figure 20B It shows Figure 20A The diagram shown is a diagram of an example of the configuration of the post-code PC1 for the normal recording format. Figure 20B , which are arranged continuously in the radial direction, show the track (even-numbered track) TR2k, the track (odd-numbered track) TR2k+1, the track (even-numbered track) TR2k+2, and the track (odd-numbered track) TR2k+3. Here, k≥1. Figure 20B In the example, tracks TR2k to TR2k+3 are arranged in the order in which they are listed, facing outward. Figure 20B The servo area (even-numbered servo area) SV2k, the servo area (odd-numbered servo area) SV2k+1, the servo area (even-numbered servo area) SV2k+2, and the servo area (odd-numbered servo area) SV2k+3 are shown. The servo areas SV2k to SV2k+3 are arranged in the order in which they are shown in the direction of travel. Figure 20B In the servo area SV2k ~ SV2k + 3 is equivalent to the normal servo area. Figure 20B In the example, servo areas SV2k to SV2k+3 include post-code PC1. Post-code PC1 of servo area SV2k includes post-code data (next post-code data) of servo area SV2k+1. Post-code PC1 of servo area SV2k+1 includes post-code data (next post-code data) of servo area SV2k+2. Post-code PC1 of servo area SV2k+2 includes post-code data (next post-code data) of servo area SV2k+3. Hereinafter, "a servo area adjacent in the direction of travel of a predetermined servo area" may be referred to as the "next servo area," "a servo area adjacent in the direction of travel of the next servo area" may be referred to as the "next servo area," and "a servo area adjacent in the direction of travel of the next servo area" may be referred to as the "next servo area," and "a servo area adjacent in the direction of travel of the next next servo area" may be referred to as the "three subsequent servo areas."

[0142] exist Figure 20B In the example shown, the servo pattern management unit 620 writes the post code PC1 into the servo areas SV2k to SV2k+3 of the tracks TR2k to TR2k+3 in the normal recording area of ​​the disk 10, respectively.

[0143] Figure 21A This is a schematic diagram showing an example of the normal recording format post-code PC2 according to this embodiment. Figure 21A 1 shows the length PCL2 of the postcode (or postcode) PC2 used in the normal recording format.

[0144] exist Figure 21A In the example shown, the normal recording format postcode PC2 includes a postcode preamble, a postcode synchronization mark, and postcode data 2 (Postcode data 2). Figure 21AIn the example shown, in the normal recording type post-code PC2, the post-code preamble, post-code synchronization mark, and post-code data 2 are arranged continuously in the order described in the direction of travel. The normal recording type post-code PC2 is a post-code arranged in a servo sector used in the short servo process and used in the write process of the normal recording area. The normal recording type post-code PC2 includes post-code data used in the next servo sector and post-code data used in the servo sector adjacent in the direction of travel of the next servo sector (hereinafter also referred to as the next-next post-code data). The data length of the post-code data 2 is, for example, 29 bits. The length PCL2 of the normal recording type post-code PC2 is, for example, greater than the length PCL1 of the normal recording type post-code PC1. For example, the length PCL2 of the normal recording type post-code PC2 is approximately twice the length PCL1 of the normal recording type post-code PC1.

[0145] The servo pattern management unit 620, for example, sets a predetermined area as a normal recording area and writes a normal recording type post-code PC2 into the normal servo sectors of the area. For example, the servo pattern management unit 620 sets the zone servo boundary ZB1 as the normal recording area and writes the normal recording type post-code PC2 as post-code X1 into the normal servo sector SVS1 within the zone servo boundary ZB1. For example, the servo pattern management unit 620 sets the zone servo boundary ZB2 as the normal recording area and writes the normal recording type post-code PC2 as post-code X5 into the normal servo sector SVS5 within the zone servo boundary ZB2. For example, the servo pattern management unit 620 sets the entire disk 10 as the normal recording area and writes the normal recording type post-code PC2 as post-code X1, X3, X5, and X7 into the normal servo sectors SVS1, SVS3, SVS5, or SVS7 throughout the entire disk 10.

[0146] Figure 21B It shows Figure 21A The diagram shown is a diagram of an example of the configuration of the post-code PC2 for the normal recording format. Figure 21B In the example, servo areas SV2k and SV2k+2 are equivalent to normal servo areas. Figure 21BIn the example, servo areas SV2k+1 and SV2k+3 correspond to short servo areas. Servo areas SV2k and SV2k+2 include postamble PC2. Postamble PC2 of servo area SV2k includes postamble data (next postamble data) used in servo area SV2k+1 and postamble data (next-next postamble data) of servo area SV2k+2. Postamble PC2 of servo area SV2k+2 includes postamble data (next postamble data) used in servo area SV2k+3 and postamble data (next-next postamble data) used in the servo area following servo area SV2k+3. Servo areas SV2k+1 and SV2k+3 do not include postambles.

[0147] exist Figure 21B In the example shown, the servo pattern management unit 620 writes postcode PC2 into servo areas SV2k and SV2k+2 of tracks TR2k to TR2k+3 in the normal recording area of ​​the disk 10. The servo pattern management unit 620 does not write postcode PC2 into servo areas SV2k+1 and SV2k+3 of tracks TR2k to TR2k+3 in the normal recording area of ​​the disk 10.

[0148] Figure 22A This is a schematic diagram showing an example of the normal recording format post-code PC3 according to this embodiment. Figure 22A 1 shows the length PCL3 of the postcode (or postcode) PC3 used in the normal recording format.

[0149] exist Figure 22A In the example shown, the normal recording format postcode PC3 includes a postcode preamble, a postcode synchronization flag, and postcode data 3 (Postcode data 3). Figure 22AIn the example shown, in the normal recording type post-code PC3, the post-code preamble, post-code synchronization mark, and post-code data 3 (Postcode data 3) are arranged continuously in the order described in the direction of travel. The normal recording type post-code PC3 is a post-code arranged at a position adjacent in the direction of travel to the additional pattern of the servo sector used in the short servo process and in the read process of the normal recording area. The normal recording type post-code PC3 includes post-code data (next post-code) used in the next servo sector and post-code data (next post-code data) used in the next next servo sector. The data length of post-code data 3 is, for example, 29 bits. The length PCL3 of the normal recording type post-code PC3 is, for example, the same as the length PCL2 of the normal recording type post-code PC2. The length PCL3 of the normal recording type post-code PC3 is, for example, greater than the length PCL1 of the normal recording type post-code PC1. For example, the length PCL3 of the normal recording type postcode PC3 is approximately twice the length PCL1 of the normal recording type postcode PC1.

[0150] The servo pattern management unit 620, for example, sets a predetermined area as a normal recording area and writes the normal recording type post-code PC3 so as not to overwrite the supplemental pattern adjacent to the short servo sector's supplemental pattern in the area in the direction of travel. For example, the servo pattern management unit 620 sets the entire disk 10 as the normal recording area and writes the normal recording type post-code PC3 as post-codes X2, X4, X6, and X8 to the short servo sectors SVS2, SVS4, SVS6, and SVS8, respectively, throughout the entire disk 10.

[0151] Figure 22B It shows Figure 22A The diagram shows an example of the configuration of the postcode PC3 for the normal recording format. Figure 22B In the example, servo areas SV2k and SV2k+2 are equivalent to normal servo areas. Figure 22BIn the example, servo areas SV2k+1 and SV2k+3 correspond to short servo areas. Servo areas SV2k and SV2k+2 include post-code PC2. Post-code PC2 of servo area SV2k includes post-code data (next post-code data) used in servo area SV2k+1 and post-code data (next-next post-code data) used in servo area SV2k+2. Post-code PC2 of servo area SV2k+2 includes post-code data (next post-code data) used in servo area SV2k+3 and post-code data (next-next post-code data) used in the servo area next to servo area SV2k+3. Servo areas SV2k+1 and SV2k+3 include additional patterns and post-code PC3. Post-code PC3 of servo area SV2k+1 includes post-code data used in servo area SV2k+1 during the read process and post-code data used in servo area SV2k+2 during the read process. The post-code PC3 of the servo area SV2k+3 includes post-code data (next post-code data) used in the servo area SV2k+3 during the read process and post-code data used in the next servo area after the servo area SV2k+3 during the read process.

[0152] exist Figure 22B In the example shown, the servo pattern management unit 620 writes the post code PC2 into the servo areas SV2k and SV2k+2 in the tracks TR2k to TR2k+3 of the normal recording area of ​​the disk 10. Figure 22B In the example shown, the servo pattern management unit 620 writes the additional pattern and the postcode PC3 in the servo areas SV2k+1 and SV2k+3 in the tracks TR2k to TR2k+3 in the normal recording area of ​​the disk 10.

[0153] Figure 23A 1 is a schematic diagram showing an example of the post code PC4 for the shingled recording type according to the present embodiment. Figure 23A 1 shows the length PCL4 of the postcode (or postcode) PC4 used in the shingled recording format.

[0154] exist Figure 23A In the example shown, the postcode PC4 for the shingled recording format includes a postcode preamble, a postcode synchronization flag, and postcode data 4 (Postcode data 4). Figure 23AIn the example shown, in the shingled recording type post-code PC4, the post-code preamble, post-code synchronization mark, and post-code data 4 (Postcode data 4) are arranged continuously in the order described in the direction of travel. The shingled recording type post-code PC4 is a post-code arranged in a servo sector that is not used in the short servo process and is used in the write process (and read process) of the shingled recording area (hereinafter also referred to as the shingled recording area). The shingled recording type post-code PC4 includes post-code data used in the next servo sector and post-code data used in the next-next servo sector. The data length of the post-code data 4 is, for example, 30 bits. The length PCL4 of the shingled recording type post-code PC4 is, for example, greater than the length PCL1 of the normal recording type post-code PC1. For example, the length PCL4 of the shingled recording type post-code PC4 is approximately twice the length PCL1 of the normal recording type post-code PC1.

[0155] The servo pattern management unit 620, for example, sets a predetermined area as a shingled recording area and writes a shingled recording type post-code PC4 into the normal servo sectors of the area. For example, the servo pattern management unit 620 sets the segment servo boundary ZB1 as the shingled recording area and writes the shingled recording type post-code PC4 as post-code X1 into the normal servo sector SVS1 within the segment servo boundary ZB1. For example, the servo pattern management unit 620 sets the segment servo boundary ZB2 as the shingled recording area and writes the shingled recording type post-code PC4 as post-code X5 into the normal servo sector SVS5 within the segment servo boundary ZB2. For example, the servo pattern management unit 620 sets the entire disk 10 as the normal recording area and writes the shingled recording type post-code PC4 as post-codes X1, X3, X5, and X7 into the normal servo sectors SVS1, SVS3, SVS5, and SVS7, respectively, throughout the entire disk 10.

[0156] Figure 23B It shows Figure 23A The diagram shows an example of the configuration of the post-code PC4 for the shingled recording format. Figure 23B In the servo area SV2k ~ SV2k + 3 is equivalent to the normal servo area. Figure 23BIn the servo area SV2k to SV2k+3, each includes multiple post-codes PC4. In the servo areas SV2k to SV2k+3, the multiple post-codes PC4 are arranged in a staggered pattern. Tracks TR2k and TR2k+2 of the servo area SV2k have post-codes PC4 used during the write process. Tracks TR2k+1 and TR2k+3 of the servo area SV2k+1 have post-codes PC4 used during the write process. Tracks TR2k and TR2k+2 of the servo area SV2k+2 have post-codes PC4 used during the write process. Tracks TR2k+1 and TR2k+3 of the servo area SV2k+3 have post-codes PC4 used during the write process.

[0157] exist Figure 23B In the illustrated example, the servo pattern management unit 620 writes the postcode PC4 used during the write process into the servo areas SV2k and SV2k+2 of the tracks TR2k and TR2k+2 in the shingled recording area of ​​the disk 10. The servo pattern management unit 620 also writes the postcode PC4 used during the write process into the servo areas SV2k+1 and SV2k+3 of the tracks TR2k+1 and TR2k+3 in the shingled recording area of ​​the disk 10.

[0158] like Figure 23B As shown, in a shingled recording area where shingled recording is performed, the data track pitch is narrow (or the tracks per inch (TPI) is high). Therefore, in order to ensure a post-code read offset margin (for example, the range within which the post-code can be read without error), the post-codes of a plurality of servo areas SV are arranged in a staggered manner between two adjacent tracks. For example, a post-code is arranged for every two data track pitches in the radial direction of the same servo area SV, and is arranged for every other servo area in a plurality of servo areas SV arranged continuously in the circumferential direction.

[0159] Figure 24A 1 is a schematic diagram showing an example of the post code PC5 for the shingled recording type according to the present embodiment. Figure 24A 1 shows the length PCL5 of the postcode (or postcode) PC5 used in the shingled recording format.

[0160] exist Figure 24A In the example shown, the postcode PC5 for the shingled recording format includes a postcode preamble, a postcode synchronization flag, and postcode data 5 (Postcode data 5). Figure 24AIn the example shown, in the shingled recording type post-code PC5, the post-code preamble, post-code synchronization mark, and post-code data 5 (Postcode data 5) are arranged consecutively in the order shown in the traveling direction. The shingled recording type post-code PC5 is a post-code arranged in the servo sector used in the short servo process and in the write process of the shingled recording area. The post-code PC5 for the shingled recording format includes post-code data used in the next servo sector (also referred to as "next post-code data"), post-code data used in the next-next servo sector (also referred to as "next post-code data"), post-code data used in the servo sector adjacent in the direction of travel of the next-next servo sector (also referred to as "three subsequent servo sectors"), and post-code data used in the servo sector adjacent in the direction of travel of the three subsequent servo sectors (also referred to as "four subsequent servo sectors") (also referred to as "four subsequent post-code data"). The data length of post-code data 5 is, for example, 58 bits. The length PCL5 of the post-code PC5 for the shingled recording format is, for example, greater than the length PCL1 of the post-code PC1 for the normal recording format. For example, the length PCL5 of the post-code PC5 for the shingled recording mode is approximately four times the length PCL1 of the post-code PC1 for the normal recording mode.

[0161] The servo pattern management unit 620, for example, sets a predetermined area as a shingled recording area and writes a shingled recording type post-code PC5 into the normal servo sectors of the area. For example, the servo pattern management unit 620 sets the zone servo boundary ZB1 as the shingled recording area and writes the shingled recording type post-code PC5 as post-code X1 into the normal servo sector SVS1 within the zone servo boundary ZB1. For example, the servo pattern management unit 620 sets the zone servo boundary ZB2 as the shingled recording area and writes the shingled recording type post-code PC5 as post-code X5 into the normal servo sector SVS5 within the zone servo boundary ZB2. For example, the servo pattern management unit 620 sets the entire disk 10 as the shingled recording area and writes the shingled recording type post-code PC5 as post-code X1, X3, X5, and X7 into the normal servo sectors SVS1, SVS3, SVS5, and SVS7, respectively, throughout the entire disk 10.

[0162] Figure 24B It shows Figure 24A The diagram shows an example of the configuration of the post-code PC5 for the shingled recording format. Figure 24BThe servo area (even-numbered servo area) SV4k, the servo area (odd-numbered servo area) SV4k+1, the servo area (even-numbered servo area) SV4k+2, and the servo area (odd-numbered servo area) SV4k+3 are shown. The servo areas SV4k to SV4k+3 are arranged in the order in which they are shown in the direction of travel. Figure 24B In the servo area SV4k and SV4k+2 are equivalent to the normal servo area. Figure 24B In the example, servo areas SV4k+1 and SV4k+3 correspond to short servo areas. Servo areas SV4k and SV4k+2 include post-code PC5. Post-code PC5 of servo area SV4k includes post-code data used in servo area SV4k+1, post-code data used in servo area SV4k+2, post-code data used in servo area SV4k+3, and post-code data used in the servo area following servo area SV4k+3 (post-code data four times later). Post-code PC5 of servo area SV4k+2 includes post-code data used in servo area SV4k+3, post-code data used in the servo area following servo area SV4k+3, post-code data used in the next servo area following servo area SV4k+3, and post-code data used in the servo area following servo area SV4k+3. Servo areas SV4k+1 and SV4k+3 do not include post-codes.

[0163] exist Figure 24B In the illustrated example, the servo pattern management unit 620 writes the post code PC5 into the servo areas SV4k and SV4k+2 of the tracks TR2k and TR2k+3 in the shingled recording area of ​​the disk 10. The servo pattern management unit 620 does not write the post code into the servo areas SV2k+1 and SV2k+3 of the tracks TR2k to TR2k+3 in the shingled recording area of ​​the disk 10.

[0164] Figure 25A This is a schematic diagram showing an example of the hybrid recording format post-code PC6 according to this embodiment. Figure 25A 1 shows the length PCL6 of the postcode (or postcode) PC6 for the mixed recording format.

[0165] exist Figure 25AIn the example shown, the hybrid recording type post-code PC6 includes the normal recording type post-code PC1 and the shingled recording type post-code PC4. In the hybrid recording type post-code PC6, the shingled recording type post-code PC4 is adjacent to the normal recording type post-code PC1 in the direction of travel. In addition, in the hybrid recording type post-code PC6, the normal recording type post-code PC1 and the shingled recording type post-code PC4 may also be arranged at intervals in the circumferential direction. The hybrid recording type post-code PC6 includes a post-code preamble, a post-code synchronization mark, post-code data 1 (Postcodedata 1), a post-code preamble, a post-code synchronization mark and post-code data 4 (Postcodedata 4). In Figure 25A In the example shown, in the shingled recording type post-code PC4, the post-code preamble, post-code synchronization mark, post-code data 1, post-code preamble, post-code synchronization mark, and post-code data 4 are arranged continuously in the order described in the direction of travel. The hybrid recording type post-code PC6 is a post-code arranged in a servo sector that is not used in the short servo process and is used in the write process of the hybrid recording area (hereinafter also referred to as the hybrid recording area). The data length of the hybrid recording type post-code data 6 is, for example, 45 bits. The data length of the hybrid recording type post-code data 6 is equivalent to the sum of the data lengths of the normal recording type post-code PC1 and the shingled recording type post-code PC4. The length PCL6 of the hybrid recording type post-code data 6 is, for example, equivalent to the sum of the length PCL1 of the normal recording type post-code PC1 and the length PCL4 of the shingled recording type post-code PC4. For example, the length PCL6 of the hybrid recording format post-code data 6 is approximately three times the length PCL1 of the normal recording format post-code PC1.

[0166] The servo pattern management unit 620, for example, sets a predetermined area as a hybrid recording area and writes a hybrid recording type post-code PC6 into the normal servo sectors in the area. For example, the servo pattern management unit 620 sets a predetermined area of ​​the disk 10 as a hybrid recording area and writes the hybrid recording type post-code PC6 as post-codes X3 and X7 into the normal servo sectors SVS3 and SVS7, respectively, in the predetermined area of ​​the disk 10.

[0167] Figure 25B It shows Figure 25A The diagram shows an example of the configuration of the post-code PC6 for the hybrid recording format. Figure 25B In the servo area SV4k ~ SV4k + 3 is equivalent to the normal servo area. Figure 25BIn the example, servo areas SV4k to SV4k+3 include post-code PC6. Tracks TR2k to TR2k+3 of servo area SV4k have post-code PC1. Tracks TR2k and TR2k+2 of servo area SV4k have post-code PC4. Tracks TR2k to TR2k+3 of servo area SV4k+1 have post-code PC1. Tracks TR2k+1 and TR2k+3 of servo area SV4k+1 have post-code PC4. Tracks TR2k to TR2k+3 of servo area SV4k+2 have post-code PC1. Tracks TR2k and TR2k+2 of servo area SV4k+2 have post-code PC4. Tracks TR2k to TR2k+3 of servo area SV4k+3 have post-code PC1. Tracks TR2k+1 and TR2k+3 of servo area SV4k+3 have post-code PC4. In addition, although not shown in the drawings, the data track from which the post-code PC1 is read and the data track from which the post-code PC4 is read may be different.

[0168] exist Figure 25B In the example shown, the servo pattern management unit 620 writes postcode PC1 into servo areas SV4k and SV4k+2 of tracks TR2k through TR2k+3 in the mixed recording area of ​​the disk 10. The servo pattern management unit 620 writes postcode PC4 into servo areas SV4k and SV4k+2 of track TR2k and track k+2 in the mixed recording area of ​​the disk 10.

[0169] exist Figure 25B In the example shown, the servo pattern management unit 620 writes postcode PC1 into servo areas SV4k+1 and SV4k+3 of tracks TR2k through TR2k+3 in the mixed recording area of ​​the disk 10. The servo pattern management unit 620 writes postcode PC4 into servo areas SV4k+1 and SV4k+3 of tracks TR2k+1 and TR2k+3 in the mixed recording area of ​​the disk 10.

[0170] Figure 26A This is a schematic diagram showing an example of the hybrid recording format post-code PC7 according to this embodiment. Figure 26A The length PCL7 of the postcode (or postcode) PC7 for the mixed recording format is shown in FIG.

[0171] exist Figure 26AIn the example shown, the hybrid recording type post-code PC7 includes the normal recording type post-code PC2 and the shingled recording type post-code PC5. In the hybrid recording type post-code PC7, the shingled recording type post-code PC5 is adjacent to the normal recording type post-code PC2 in the direction of travel. In addition, in the hybrid recording type post-code PC7, the normal recording type post-code PC2 and the shingled recording type post-code PC5 may also be arranged at intervals in the circumferential direction. The hybrid recording type post-code PC7 includes a post-code preamble, a post-code synchronization mark, post-code data 2 (Postcodedata 2), a post-code preamble, a post-code synchronization mark and post-code data 5 (Postcodedata 5). In Figure 26A In the example shown, in the hybrid recording type post-code PC7, the post-code preamble, post-code synchronization mark, post-code data 2, post-code preamble, post-code synchronization mark, and post-code data 5 are arranged continuously in the order shown in the direction of travel. Hybrid recording type post-code PC7 is a post-code arranged in a servo sector used in short servo processing and in the write processing of the shingled recording area. The data length of hybrid recording type post-code data 7 is, for example, 87 bits. The data length of hybrid recording type post-code data 7 is equivalent to the sum of the data lengths of normal recording type post-code PC2 and shingled recording type post-code PC5. The length PCL7 of hybrid recording type post-code data 7 is, for example, equivalent to the sum of the length PCL2 of normal recording type post-code PC2 and the length PCL5 of shingled recording type post-code PC5. For example, the length PCL7 of the hybrid recording format post-code data 7 is approximately six times the length PCL1 of the normal recording format post-code PC1.

[0172] The servo pattern management unit 620, for example, sets a predetermined area as a hybrid recording area and writes a hybrid recording type post-code PC7 into the normal servo sectors in the area. For example, the servo pattern management unit 620 sets a predetermined area of ​​the disk 10 as a hybrid recording area and writes the hybrid recording type post-code PC7 as post-codes X3 and X7 into the normal servo sectors SVS3 and SVS7, respectively, in the predetermined area of ​​the disk 10.

[0173] Figure 26B It shows Figure 26A The diagram shows an example of the configuration of the post-code PC7 for the hybrid recording format. Figure 26B In the servo area SV4k and SV4k+2 are equivalent to the normal servo area. Figure 26BIn the example, servo areas SV4k+1 and SV4k+3 correspond to short servo areas. Servo areas SV4k and SV4k+2 include post-code PC7. Tracks TR2k through TR2k+3 of servo area SV4k have post-code PC2. Tracks TR2k and TR2k+2 of servo area SV4k have post-code PC5. Tracks TR2k through TR2k+3 of servo area SV4k+2 have post-code PC2. Tracks TR2k and TR2k+2 of servo area SV4k+2 have post-code PC5. Servo areas SV4k+1 and SV4k+3 do not include post-codes.

[0174] exist Figure 26B In the example shown, the servo pattern management unit 620 writes postcode PC2 into servo areas SV4k and SV4k+2 of tracks TR2k through TR2k+3 in the mixed recording area of ​​the disk 10. The servo pattern management unit 620 writes postcode PC5 into servo areas SV4k and SV4k+2 of tracks TR2k and k+2 in the mixed recording area of ​​the disk 10.

[0175] exist Figure 26B In the example shown, the servo pattern management unit 620 does not write the post code into the servo areas SV4k+1 and SV4k+3 of tracks TR2k to TR2k+3 in the mixed recording area of ​​the disk 10.

[0176] Figures 20A to 26B In the example shown, the servo pattern management unit 620 sets the segment servo boundary ZB as a normal recording area and writes the post code PC1 to the servo area SV of the segment servo boundary ZB, and also sets the area outside the segment servo boundary ZB of the disk 10 as a normal recording area and writes the post code PC2 to the servo area SV outside the segment servo boundary ZB of the disk 10. As a result, compared with the case where the entire surface of the disk 10 is set as a normal recording area and the post code PC2 is written to the servo area SV of the entire surface of the disk 10, the segment servo gap can be reduced, thereby improving the format efficiency of the disk 10.

[0177] Figures 20A to 26B In the example shown, the servo pattern management unit 620 sets the segment servo boundary ZB as a normal recording area and writes the postcode PC1 or the postcode PC2 to the servo area SV of the segment servo boundary ZB, and also sets the area outside the segment servo boundary ZB of the disk 10 as a normal recording area and writes the additional pattern and the postcode PC3 to the servo area SV outside the segment servo boundary ZB of the disk 10. As a result, compared with the case where the entire surface of the disk 10 is set as a normal recording area and the additional pattern and the postcode PC3 are written to the servo area SV of the entire surface of the disk 10, the segment servo gap can be reduced, thereby improving the format efficiency of the disk 10.

[0178] Figures 20A to 26B In the example shown, the servo pattern management unit 620 sets the segment servo boundary ZB as a normal recording area or a shingled recording area and writes post-code PC1, post-code PC2 or post-code PC4 to the servo area SV of the segment servo boundary ZB, and also sets the area outside the segment servo boundary ZB of the disk 10 as a shingled recording area and writes post-code PC5 to the servo area SV outside the segment servo boundary ZB of the disk 10. As a result, the segment servo gap can be reduced compared to the case where the entire surface of the disk 10 is set as a shingled recording area and the post-code PC5 is written to the servo area SV of the entire surface of the disk 10, thereby improving the format efficiency of the disk 10.

[0179] Figures 20A to 26B In the example shown, the servo pattern management unit 620 sets the segment servo boundary ZB as a normal recording area, a shingled recording area or a mixed recording area and writes post-code PC1, post-code PC2, post-code PC4 or post-code PC6 to the servo area SV of the segment servo boundary ZB, and also sets the area outside the segment servo boundary ZB of the disk 10 as a shingled recording area and writes post-code PC7 to the servo area SV outside the segment servo boundary ZB of the disk 10. As a result, the segment servo gap can be reduced compared to the case where the entire surface of the disk 10 is set as a shingled recording area and the post-code PC7 is written to the servo area SV of the entire surface of the disk 10, thereby improving the format efficiency of the disk 10.

[0180] Figures 20A to 26B In the example shown, the servo pattern management unit 620 sets the segment servo boundary ZB as a normal recording area or a shingled recording area and writes a post-code for a normal recording type or a post-code for a shingled recording type to the servo area SV of the segment servo boundary ZB, and sets the area of ​​the disk 10 outside the segment servo boundary ZB as a normal recording area, a shingled recording area or a mixed recording area and writes a post-code for a normal recording type, a post-code for a shingled recording type or a post-code for a mixed recording type to the servo area SV of the area of ​​the disk 10 outside the segment servo boundary ZB.

[0181] Figures 20A to 26B In the example shown, when the servo pattern management unit 620 accesses an area other than the area using the pre-segment servo sectors in the normal recording area, the post code is written to the even-numbered servo areas SV, so the post code is read from the even-numbered servo areas SV. When the servo pattern management unit 620 accesses an area using the pre-segment servo sectors in the normal recording area, the post code is written to all the servo areas SV of the disk 10, so the post code is read from all the servo areas SV of the disk 10.

[0182] Figures 20A to 26BIn the example shown, when the servo pattern management unit 620 accesses an area other than the area using the pre-sector servo sectors in the shingled recording area, in the odd-numbered track, the post-code is written to the servo area SV4k+2, so the post-code is read from the servo area SV4k+2. In the even-numbered track, the post-code is written to the servo area SV4k, so the post-code is read from the servo area SV4k. When the servo pattern management unit 620 accesses an area using the pre-sector servo sectors in the shingled recording area, in the odd-numbered track, the post-code is written to the odd-numbered servo area SV, so the post-code is read from the odd-numbered servo area SV. In the even-numbered track, the post-code is written to the even-numbered servo area SV, so the post-code is read from the even-numbered servo area SV.

[0183] Figures 20A to 26B In the illustrated example, when the servo pattern management unit 620 accesses an area other than the area using the pre-segment servo sectors in the mixed recording area, it determines whether the area is a normal recording area or a shingled recording area, and reads post-code PC2 if the area is a normal recording area, and reads post-code PC5 if the area is a shingled recording area. When the servo pattern management unit 620 accesses an area using the pre-segment servo sectors in the mixed recording area, it determines whether the area is a normal recording area or a shingled recording area, and reads post-code PC1 if the area is a normal recording area, and reads post-code PC4 if the area is a shingled recording area.

[0184] The servo pattern management unit 620 may also record the postcode format set for each area of ​​the disk 10 in a predetermined recording area, such as the system area 10c of the disk 10 or the non-volatile memory 80. Furthermore, the servo pattern management unit 620 may pre-define the postcode format set for each area of ​​the disk 10 as a fixed value within the firmware.

[0185] Figure 27 Schematic diagram showing an example of the change in the format loss in the radial direction of the disk 10. Figure 27 In FIG. 1 , the magnetic disk device 1 has two sector servo boundaries ZB in the radial direction of the disk 10. Figure 27 In the figure, the horizontal axis represents the radial position and the vertical axis represents the format loss [%]. Figure 27 In the vertical axis of , the format loss increases as it goes toward the front end of the large arrow, and decreases as it goes toward the front end of the small arrow. Figure 27 In the horizontal axis of , the radial position advances outward as the tip of the arrow points to the outside, and advances inward as the tip of the arrow points to the inside. Figure 27 The variation of format loss with respect to radial position is shown in FLL1.

[0186] exist Figure 27 In the example shown, the sector servo boundary ZB (eg, sector data pattern) has a larger format loss than other areas due to the length of the sector servo gap, etc. In other words, the sector servo boundary ZB has a lower format efficiency than other areas.

[0187] exist Figure 27 In the example shown, the servo pattern management unit 620 uniquely determines the segment servo boundary ZB based on the servo pattern and segment division design during SSW, and selects a postcode that shortens the segment servo gap and improves the format efficiency of the two segment servo boundaries ZB to be written into the servo area SV of the segment servo boundary ZB. For example, a postcode of a length shorter than the length of the postcode of the segment servo boundary ZB or the area other than the previous segment servo sector is written.

[0188] Figure 28 Schematic diagram showing an example of the change in the format loss in the radial direction of the disk 10. Figure 28 In FIG. 1 , the magnetic disk device 1 has six sector servo boundaries ZB in the radial direction of the disk 10. Figure 28 In the figure, the horizontal axis represents the radial position and the vertical axis represents the format loss [%]. Figure 28 In the vertical axis of , the format loss increases as it goes toward the front end of the large arrow, and decreases as it goes toward the front end of the small arrow. Figure 28 In the horizontal axis of , the radial position advances outward as the tip of the arrow points to the outside, and advances inward as the tip of the arrow points to the inside. Figure 28 The variation of format loss with respect to radial position is shown in FLL2.

[0189] exist Figure 28 In the example shown, the sector servo boundary ZB (eg, sector data pattern) has a larger format loss than other areas due to the length of the sector servo gap, etc. In other words, the sector servo boundary ZB has a lower format efficiency than other areas.

[0190] During SSW, the servo pattern management unit 620 uniquely determines the segment servo boundary ZB based on the servo pattern and the segment division design, and selects and writes a postcode into the servo area SV of the segment servo boundary ZB, which shortens the segment servo gap and improves the format efficiency of the five segment servo boundaries ZB. For example, a postcode with a length shorter than the length of the postcode in the segment servo boundary ZB or the area other than the previous segment servo sector is selected and written.

[0191] Figure 29 This is a flowchart showing an example of a post-code writing processing method according to the present embodiment.

[0192] When writing a postamble, the system controller 130 determines whether it is a pre-sector servo sector (B2901). If it is not a pre-sector servo sector (No in B2901), the system controller 130 selects a first postamble (B2902), writes the selected postamble to a predetermined area of ​​the disk 10 (B2904), and terminates the process. The first postamble includes, for example, postamble PC2, postamble PC3, postamble PC5, and postamble PC7. If it is a pre-sector servo sector (Yes in B2901), the system controller 130 selects a second postamble that is smaller than the first postamble (B2903), writes the selected postamble to the sector servo boundary ZB (B2904), and terminates the process. The second postamble includes postamble PC1, postamble PC2, postamble PC3, postamble PC4, postamble PC5, and postamble PC6.

[0193] Figure 30 This is a flowchart showing an example of a post-code reading processing method according to the present embodiment.

[0194] When the system controller 130 reads a post-code, it determines whether it is a pre-sector servo sector (B3001). If it is not a pre-sector servo sector (No in B3001), the system controller 130 selects the first post-code (B3002), reads the selected post-code (B3004), and terminates the process. The first post-code includes, for example, post-code PC2, post-code PC3, post-code PC5, and post-code PC7. If it is a pre-sector servo sector (Yes in B3001), the system controller 130 selects the second post-code (B3003), reads the selected post-code (B3004), and terminates the process. The second post-code includes, for example, post-code PC1, post-code PC2, post-code PC3, post-code PC4, post-code PC5, and post-code PC6.

[0195] According to this embodiment, magnetic disk device 1 sets a write pattern that improves the format efficiency of a predetermined area and writes a postamble that improves the format efficiency of that area from among the multiple postambles corresponding to the set write pattern into that area. When using the leading sector servo sector of the sector servo boundary, magnetic disk device 1 selects a postamble format that is shorter than the postambles in other areas. This shortens the sector servo gap during SSW and improves format efficiency. Consequently, magnetic disk device 1 can improve format efficiency.

[0196] Next, a magnetic disk device according to another embodiment of the first embodiment will be described. In the other embodiment of the first embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0197] (Second embodiment)

[0198] The magnetic disk device 1 according to the second embodiment differs from the magnetic disk device 1 according to the first embodiment described above in the configuration of the servo area SV of the disk 10 .

[0199] Figure 31 It is a schematic diagram showing an example of the arrangement of the servo areas SV of the disk 10 according to the second embodiment.

[0200] The plurality of servo areas SV may extend linearly from the inner periphery to the outer periphery and be discretely arranged at predetermined intervals in the circumferential direction, or may extend spirally from the inner periphery to the outer periphery and be discretely arranged at predetermined intervals in the circumferential direction, for example.

[0201] For example, the plurality of servo areas SV may consist only of normal servo areas. For example, the plurality of servo areas SV may also consist of normal servo areas and short servo areas. For example, the odd-numbered servo areas SV in the plurality of servo areas SV may be normal servo areas, and the even-numbered servo areas SV in the plurality of servo areas SV may be short servo areas. Alternatively, the even-numbered servo areas SV in the plurality of servo areas SV may be normal servo areas, and the odd-numbered servo areas SV in the plurality of servo areas SV may be short servo areas.

[0202] The system controller 130 selects a postamble (postamble format) for each area of ​​the disk 10 based on the TPI (or track pitch) of each area of ​​the disk 10 and writes it. For example, when the entire surface of the disk 10 is configured as a shingled recording area (normal recording area or hybrid recording area), the system controller 130 selects a postamble with a length shorter than a predetermined postamble length to be written to the media buffer 10b or system area 10c having a TPI lower than a predetermined TPI threshold (wide track pitch), that is, having a low format efficiency. For example, when the entire surface of the disk 10 is configured as a shingled recording area (normal recording area or hybrid recording area), the system controller 130 selects a postamble with a length shorter than the postamble length written to the servo area SV of the user data area 10a to be written to the media buffer 10b or system area 10c having a lower TPI (wide track pitch) than the user data area 10a, that is, having a low format efficiency (small data capacity and a small number of data sectors). For example, when the user data area 10a of the disk 10 is configured as a shingled recording area and the media buffer 10b and system area 10c are configured as normal recording areas, the system controller 130 selects and writes a post-code with a length shorter than a predetermined post-code length to the media buffer 10b or system area 10c, where the TPI is lower than a predetermined TPI threshold (narrow track pitch), that is, where the format efficiency is low. In areas with low TPI, there is no need to interleave the post-codes to ensure a read bias margin for the post-codes. For example, when the entire surface of the disk 10 is configured as a shingled recording area, the system controller 130 selects and writes post-code PC4, rather than post-code PC5, to an area with low TPI (narrow track pitch). In this case, the post-code length can be shortened, improving the format efficiency of that area. Improving the format efficiency of the media buffer area allows for reallocation to the user data area, increasing the data capacity of the HDD. Furthermore, in the above description, the media buffer is taken as an example. However, in the user data area, if it is an area with low TPI (data segment), it can also be applied in the same manner.

[0203] Figure 32 This is a flowchart showing an example of a post-code writing processing method according to the second embodiment.

[0204] When writing a post-code, the system controller 130 determines whether the TPI of the predetermined area is less than or greater than a predetermined threshold (B3201). If the TPI of the predetermined area is determined to be greater than the predetermined threshold (No in B3201), the system controller 130 selects a first post-code (B3202), writes the selected post-code to the predetermined area of ​​the disk 10 (B3204), and terminates the process. The first post-code includes, for example, post-code PC5. If the TPI of the predetermined area is determined to be less than the predetermined threshold (Yes in B3201), the system controller 130 selects a second post-code that is smaller than the first post-code (B3203), writes the selected post-code to the zone servo boundary ZB (B3204), and terminates the process. The second post-code includes post-code PC4.

[0205] Figure 33 This is a flowchart showing an example of a post-code reading method according to the second embodiment.

[0206] When writing a post-code, the system controller 130 determines whether the TPI of the predetermined area is less than or greater than a predetermined threshold (B3301). If the TPI of the predetermined area is determined to be greater than the predetermined threshold (No in B3301), the system controller 130 selects a first post-code (B3302), reads the selected post-code into the predetermined area of ​​the disk 10 (B3304), and terminates the process. The first post-code includes, for example, post-code PC5. If the TPI of the predetermined area is determined to be less than the predetermined threshold (Yes in B3301), the system controller 130 selects a second post-code smaller than the first post-code (B3303), writes the selected post-code into the zone servo boundary ZB (B3304), and terminates the process. The second post-code includes post-code PC4.

[0207] According to the second embodiment, magnetic disk drive 1 selects a postcode format for each area of ​​disk 10 based on the TPI (or track pitch) of each area of ​​disk 10 and writes it. For example, when the entire surface of disk 10 is configured as a shingled recording area (normal recording area or hybrid recording area), magnetic disk drive 1 selects a postcode with a length shorter than a predetermined postcode length and writes it to the media buffer 10b or system area 10c having a TPI (wide track pitch) lower than a predetermined TPI threshold. Consequently, magnetic disk drive 1 can improve format efficiency.

[0208] While some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit 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 region having a first format efficiency and a second region having a second format efficiency lower than the first format efficiency; a head for writing data to and reading data from the disk; and The controller selects a first post-code to be written to the first area and a second post-code to be written to the second area from a plurality of post-codes, and writes the selected post-codes to the first area and the second area, respectively. The controller selects the second postcode having a second length shorter than the first length of the first postcode and writes the second postcode into the second area.

2. The magnetic disk device according to claim 1, In the second area, the first servo sector of the first servo area including servo data extending in the radial direction of the disk, the gap, and the second servo sector of the second servo area including servo data extending in the radial direction are arranged in the order described in the first direction in the circumferential direction of the disk.

3. The magnetic disk device according to claim 2, The controller writes the second postamble into the first servo sector.

4. The magnetic disk device according to claim 3, The controller determines the length of the gap according to the second postamble.

5. The magnetic disk device according to claim 4, The controller writes the first postamble into the second servo sector.

6. The magnetic disk device according to any one of claims 2 to 5, The controller writes data into the second area in a normal recording format in which data is written at intervals in the radial direction.

7. The magnetic disk device according to any one of claims 2 to 5, The controller writes data to the second area using a shingled recording method in which data is written to a plurality of tracks overlapping in the radial direction.

8. The magnetic disk device according to any one of claims 2 to 5, The controller writes data to the first area using a recording mode selected from a normal recording mode in which data is written at intervals in the radial direction and a shingled recording mode in which data is written to a plurality of tracks overlapping in the radial direction.

9. The magnetic disk device according to claim 1, The second area is arranged radially outward of the first area in the disk and is a system area for writing information required for system management or a media cache for temporarily storing data before writing to the first area.

10. The magnetic disk device according to claim 9, The controller writes data to the first area and the second area in a shingled recording method in which data is written to a plurality of tracks overlapping in the radial direction.

11. A post-code writing method, applied to a magnetic disk device, the magnetic disk device comprising: a disk having a first area with a first format efficiency and a second area with a second format efficiency lower than the first format efficiency; and a head for writing data to the disk and reading data from the disk, wherein: A first post-code to be written to the first area and a second post-code to be written to the second area are selected from a plurality of post-codes, and the selected post-codes are written to the first area and the second area, respectively. The second postcode having a second length shorter than the first length of the first postcode is selected and written into the second area.

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