Magnetic disk device

Abstract

To provide a magnetic disk device capable of improving the quality of data to be recorded in a disk while increasing the capacity of the disk.SOLUTION: A magnetic disk device includes a disk, a write head, an adjustment section, and a write processing section. The adjustment section respectively adjusts first to third adjustment values. The write processing section selects a singled magnetic recording type and can execute write processing based on the first to third adjustment values. The number of a plurality of tracks STRe of a band BAe is set to t+1 and the number of unused sectors among a plurality of sectors of the band BAe is set to e. The adjustment section adjusts the first to third adjustment values in order to establish e<t.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] An embodiment of the present invention relates to a magnetic disk drive. [Background technology]

[0002] Known magnetic disk devices include conventional magnetic recording (CMR) type (or conventional recording type) magnetic disk devices that write multiple tracks at intervals in the radial direction of the disk, shingled write magnetic recording (SMR, or shingled write recording (SWR) type magnetic disk devices that overwrite multiple tracks in the radial direction of the disk, and hybrid recording type magnetic disk devices that select between the conventional recording type and the shingled recording type. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 8,908,310 [Patent Document 2] U.S. Patent No. 9,036,284 [Patent Document 3] U.S. Patent No. 7,133,241 [Patent Document 4] U.S. Patent No. 6,445,525 Summary of the Invention [Problem to be solved by the invention]

[0004] This embodiment provides a magnetic disk device that can increase the capacity of the disk while improving the quality of data recorded on the disk. [Means for solving the problem]

[0005] A magnetic disk device according to an embodiment includes: A disk having a band including a plurality of tracks, each of the tracks including a plurality of sectors, the disk, a write head for writing data to the disk, a first adjustment value which is the number of the plurality of sectors of each of the tracks of the band, a second adjustment value which is the length of each of the sectors in the circumferential direction of the disk, and an adjustment unit for adjusting a third adjustment value which is the number of the plurality of tracks of the band respectively, a write processing unit capable of selecting a shingled recording format for writing data to the plurality of tracks in a radially overlapping manner on the disk and executing a write process based on the first to third adjustment values, wherein when the number of the plurality of tracks of the band is t + 1 and the number of unused sectors among the plurality of sectors of the band is e, the adjustment unit adjusts the first to third adjustment values so that e < t holds.

[0006] Also, a magnetic disk device according to an embodiment A disk having a band including a plurality of tracks, each of the tracks including a plurality of sectors, the disk, a write head for writing data to the disk, an adjustment unit for adjusting a first adjustment value which is the number of the plurality of sectors of each of the tracks of the band and a second adjustment value which is the length of each of the sectors in the circumferential direction of the disk respectively, a write processing unit capable of selecting a shingled recording format for writing data to the plurality of tracks in a radially overlapping manner on the disk and executing a write process based on the first and second adjustment values, wherein when the recording capacity of the band is Cb, the recording capacity of each of the sectors is Cs, the number of the plurality of sectors of each of the tracks of the band is n, the number of the plurality of tracks of the band is t + 1, a variable is k, and the number of unused sectors among the plurality of sectors of the band is e, Cb / Cs = n×t + k, n = e + k, the adjustment unit acquires information on the Cb, the Cs, and the t, and finally determines each of the n, the e, and the k so that e < t holds.

Brief Description of the Drawings

[0007] [Figure 1] FIG. 1 is a block diagram showing the configuration of a magnetic disk device according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing a part of the magnetic disk device, showing a plurality of disks and a plurality of heads. [Diagram 3] FIG. 3 is a schematic diagram showing an example of an arrangement of a plurality of servo areas and a plurality of data areas on one disk according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing three tracks in the user data area of ​​the disk shown in FIG. 3 where shingled recording processing is performed, and a write head. [Diagram 5] FIG. 5 is a schematic diagram showing three tracks of a media cache where normal recording processing of the disk shown in FIG. 3 is performed, and a write head. [Figure 6] FIG. 6 is a schematic diagram showing an example of a data write process on a disk. [Figure 7] FIG. 7 is a schematic diagram showing two bands and one guard band in the user data area shown in FIG. [Figure 8] FIG. 8 is a schematic diagram showing three sectors in one track of the band shown in FIG. [Figure 9] FIG. 9 is a schematic diagram showing one band in the user data area of ​​a disk in a comparative example, and is a diagram for explaining an example of a case where the adjustment unit does not adjust the number of unused sectors in the band. [Figure 10] FIG. 10 is a schematic diagram showing one band in the user data area of ​​the disk according to the embodiment, and is a diagram for explaining an example in which the adjustment unit adjusts the number of unused sectors in the band. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (One embodiment) A magnetic disk device 1 according to an embodiment will be described in detail below with reference to the drawings. First, the configuration of the magnetic disk device 1 will be described. FIG. 1 is a block diagram showing the configuration of the magnetic disk device 1 according to this embodiment. In this embodiment, the magnetic disk device 1 is a hybrid recording type magnetic disk device that selectively executes a normal recording type and a shingled recording type. However, the technology described below may also be applied to a shingled recording type magnetic disk device.

[0009] 1, the magnetic disk device 1 includes a plurality of, for example, 1 to 10 disks (magnetic disks) DK as recording media, a spindle motor (SPM) 20 as a drive motor, a head stack assembly 22, a driver IC 120, a head amplifier integrated circuit (hereinafter, head amplifier IC or preamplifier) ​​130, a volatile memory 70, a buffer memory (buffer) 80, a non-volatile memory 90, and a system controller 110 which is a one-chip integrated circuit. The magnetic disk device 1 is also connected to a host system (hereinafter, simply referred to as a host) 100.

[0010] Each disk DK is formed to have a diameter of, for example, 95 mm (3.5 inches) and has a recording layer (magnetic recording layer) on both sides. In this embodiment, the magnetic disk device 1 includes 1 to 10 disks DK, but the number of disks DK is not limited to this. Also, the magnetic disk device 1 may include a single disk DK.

[0011] The head stack assembly 22 can control the movement of a head HD mounted on an arm 30 to a target position on the disk DK by driving a voice coil motor (hereinafter referred to as VCM) 24, that is, can seek. The disk DK has, as its data writable areas, a user data area U available for use by the user and a system area S in which information required for system management is written.

[0012] The head HD records and reproduces information on the disk DK. The head HD has a slider as its main body, and is equipped with a write head WHD and a read head RHD mounted on the slider. The write head WHD writes data to the recording layer of the disk DK. The read head RHD reads data from a data track on the recording layer of the disk DK.

[0013] The driver IC 120, under the control of the system controller 110 (more specifically, the MPU 60 described below), controls the driving of the SPM 20 and the VCM 24. The SPM 20 supports and rotates a plurality of disks DK.

[0014] The head amplifier IC 130 includes a read amplifier and a write driver. The read amplifier amplifies a read signal read from the disk DK and outputs it to the system controller 110 (more specifically, a read / write (R / W) channel 140, which will be described later). The write driver outputs a write current corresponding to the signal output from the R / W channel 140 to the head HD.

[0015] The volatile memory 70 is a semiconductor memory in which stored data is lost when the power supply is cut off. The volatile memory 70 stores data and the like required for processing in each part of the magnetic disk device 1. The volatile memory 70 is, for example, a dynamic random access memory (DRAM) or a synchronous dynamic random access memory (SDRAM).

[0016] The buffer memory 80 is a semiconductor memory that temporarily records data and the like transmitted and received between the magnetic disk device 1 and the host 100. The buffer memory 80 may be configured integrally with the volatile memory 70. The buffer memory 80 is, for example, a DRAM, a static random access memory (SRAM), a SDRAM, a ferroelectric random access memory (FeRAM), or a magnetoresistive random access memory (MRAM).

[0017] The non-volatile memory 90 is a semiconductor memory that records stored data even if the power supply is cut off. The non-volatile memory 90 is, for example, a NOR type or NAND type flash ROM (Flash Read Only Memory: FROM).

[0018] The system controller (controller) 110 is realized, for example, by using a large scale integrated circuit (LSI) called a System-on-a-Chip (SoC) in which multiple elements are integrated on a single chip. The system controller 110 includes a read / write (R / W) channel 140, a hard disk controller (HDC) 150, and a microprocessor (MPU) 60. The system controller 110 is electrically connected to a driver IC 120, a head amplifier IC 130, a volatile memory 70, a buffer memory 80, a non-volatile memory 90, and a host 100.

[0019] The R / W channel 140 executes signal processing of read data transferred from the disk DK to the host 100 and write data transferred from the host 100 in response to instructions from the MPU 60 described later. The R / W channel 140 has a circuit or function for modulating write data. The R / W channel 140 also has a circuit or function for measuring the signal quality of the read data. The R / W channel 140 is electrically connected to, for example, the head amplifier IC 130, the HDC 150, the MPU 60, etc.

[0020] The HDC 150 controls data transfer between the host 100 and the R / W channel 140 in response to instructions from the MPU 60, which will be described later. The HDC 150 is electrically connected to, for example, the R / W channel 140, the MPU 60, the volatile memory 70, the buffer memory 80, the non-volatile memory 90, and the like.

[0021] The MPU 60 is a control unit that controls each part of the magnetic disk device 1, and is a main controller. The MPU 60 controls the VCM 24 via the driver IC 120, and executes servo control for positioning the head HD. The MPU 60 controls the write operation of data to the disk DK, and selects a storage destination for write data transferred from the host 100. The MPU 60 also controls the read operation of data from the disk DK, and controls the processing of read data transferred from the disk DK to the host 100. The MPU 60 is connected to each part of the magnetic disk device 1. The MPU 60 is electrically connected to, for example, the driver IC 120, the R / W channel 140, the HDC 150, and the like.

[0022] The MPU 60 includes a read / write processing unit 61, an adjustment unit 62, etc. The MPU 60 executes the processing of each of these units, for example, the read / write processing unit 61, the adjustment unit 62, etc., on firmware. Note that the MPU 60 may include each of these units as a circuit.

[0023] The read / write processing unit 61 has a write processing unit 61a and a read processing unit 61b. The write processing unit 61a controls the data write processing, and the read processing unit 61b controls the data read processing, according to a command from the host 100. The read / write processing unit 61 controls the VCM 24 via the driver IC 120, positions the head HD at a target position (predetermined radial position) on the disk DK, and executes the read processing or the write processing.

[0024] FIG. 2 is a perspective view showing a part of the magnetic disk device 1, and shows a plurality of disks DK and a plurality of heads HD. As shown in Fig. 2, the direction in which the disk DK rotates in the circumferential direction is referred to as the rotation direction d3. In the example shown in Fig. 2, the rotation direction is shown counterclockwise, but it may be the opposite direction (clockwise). The movement direction d2 of the head HD relative to the disk DK is opposite to the rotation direction d3. The movement direction d2 is the direction in which the head HD sequentially writes and reads data to the disk DK in the circumferential direction, that is, the direction in which the head HD moves relative to the disk DK in the circumferential direction.

[0025] The magnetic disk device 1 includes i disks, disks DK1 to DKi, and j heads, heads HD1 to HDj. In this embodiment, the number of heads HD is twice the number of disks DK (j=2×i). The disks DK1 to DKi are provided coaxially and stacked with a gap between them. The disks DK1 to DKi have the same diameter. Here, terms such as "same," "identical," "matched," and "equivalent" not only mean exactly the same, but also mean different enough to be considered substantially the same. The disks DK1 to DKi may have different diameters.

[0026] Each disc DK has a recording layer L on both sides. For example, disc DK1 has a first recording layer La1 and a second recording layer Lb1 on the opposite side of the first recording layer La1. Disc DK2 has a first recording layer La2 and a second recording layer Lb2 on the opposite side of the first recording layer La2. Disc DKi has a first recording layer Lai and a second recording layer Lbi on the opposite side of the first recording layer Lai. Each first recording layer La may be referred to as a front surface or a recording surface. Each second recording layer Lb may be referred to as a back surface or a recording surface.

[0027] Each recording layer L has a user data area U and a system area S. The first recording layer La1 has a user data area Ua1 and a system area Sa1. The second recording layer Lb1 has a user data area Ub1 and a system area Sb1. The first recording layer La2 has a user data area Ua2 and a system area Sa2. The second recording layer Lb2 has a user data area Ub2 and a system area Sb2. The first recording layer Lai has a user data area Uai and a system area Sai. The second recording layer Lbi has a user data area Ubi and a system area Sbi.

[0028] In the user data area Ua1 (first recording layer La1), the track between the double dashed lines in the figure is designated as track Ta1. In the user data area Ub1 (second recording layer Lb1), the track located on the opposite side of track Ta1 is designated as track Tb1. In the user data area Ua2 (first recording layer La2), the track between the double dashed lines in the figure is designated as track Tc1. In the user data area Ub2 (second recording layer Lb2), the track located on the opposite side of track Tc1 is designated as track Td1. In the user data area Uai (first recording layer Lai), the track between the double dashed lines in the figure is designated as track Te1. In the user data area Ubi (second recording layer Lbi), the track located on the opposite side of track Te1 is designated as track Tf1. In this embodiment, the tracks Ta1, Tb1, Tc1, Td1, Te1, and Tf1 are located on the same cylinder.

[0029] The head HD faces the disk DK. In this embodiment, one head HD faces each recording layer L of the disk DK. For example, the head HD1 faces the first recording layer La1 of the disk DK1, writes data to the first recording layer La1, and reads data from the first recording layer La1. The head HD2 faces the second recording layer Lb1 of the disk DK1, writes data to the second recording layer Lb1, and reads data from the second recording layer Lb1.

[0030] The head HD3 faces the first recording layer La2 of the disk DK2, and writes data to and reads data from the first recording layer La2. The head HD4 faces the second recording layer Lb2 of the disk DK2, and writes data to and reads data from the second recording layer Lb2. The head HDj-1 faces the first recording layer Lai of the disk DKi, and writes data to and reads data from the first recording layer Lai. The head HDj faces the second recording layer Lbi of the disk DKi, and writes data to and reads data from the second recording layer Lbi.

[0031] 3 is a schematic diagram showing an example of the arrangement of a plurality of servo regions SV and a plurality of data regions DTR of one disk DK according to this embodiment. As shown in FIG. 3, in the radial direction d1 of the disk DK, the direction toward the outer periphery of the disk DK is called the outward direction (outside), and the opposite direction to the outward direction is called the inward direction (inside). In FIG. 3, the user data area U is divided into an inner area IR located inward, an outer area OR located outward, and a middle area MR located between the inner area IR and the outer area OR.

[0032] The disk DK has a plurality of servo areas SV and a plurality of data areas DTR. The plurality of servo areas SV may extend radially in the radial direction of the disk DK and be arranged discretely at a predetermined interval in the circumferential direction. The plurality of servo areas SV may extend linearly from the inner circumference to the outer circumference and be arranged discretely at a predetermined interval in the circumferential direction. The plurality of servo areas SV may extend spirally from the inner circumference to the outer circumference and be arranged discretely at a predetermined interval in the circumferential direction. The plurality of servo areas SV may also be arranged in an island shape in the radial direction and be arranged discretely at a predetermined interval in the circumferential direction.

[0033] Hereinafter, one servo area SV in a given track may be referred to as a "servo sector." Note that a "servo area SV" may also be referred to as a "servo sector SV." A servo sector contains servo data. Hereinafter, "the arrangement of several servo data constituting a servo sector" may also be referred to as a "servo pattern." Note that "servo data written to a servo sector" may also be referred to as a "servo sector."

[0034] Each of the data areas DTR is disposed between the servo areas SV. For example, the data area DTR corresponds to an area between two consecutive servo areas SV in the circumferential direction. Hereinafter, one data area DTR in a given track may be referred to as a "data sector". The "data area DTR" may be referred to as a "data sector DTR". The data sector includes user data. The "user data written in the data sector" may be referred to as a "data sector". The "data sector" may be referred to as "user data". A "pattern consisting of several data" may be referred to as a "data pattern". In the example shown in FIG. 3, the data pattern of a given track is composed of a plurality of servo data (servo sectors) and a plurality of user data (data sectors).

[0035] The servo area SV has a plurality of zone servo areas ZSV, etc. In addition to the zone servo area ZSV, the servo area SV may also include an area including a gap (a deviation in the circumferential position of two zone servo areas), an area including servo data, and a data area DTR, etc. The plurality of zone servo areas ZSV are discretely arranged along the radial direction. Each of the plurality of zone servo areas ZSV extends in the radial direction.

[0036] One zone servo area (servo area) ZSV in a specified track may be referred to as a "zone servo sector" or a "servo sector." Note that a "zone servo area (servo area) ZSV" may be referred to as a "zone servo sector ZSV" or a "servo sector ZSV." "Servo data written in a zone servo sector" may be referred to as a "zone servo sector" or a "servo sector." Hereinafter, "the arrangement of several servo data constituting a zone servo sector" may be referred to as a "zone servo pattern" or a "servo pattern." Hereinafter, one servo area SV in a specified track may be referred to as a "zone pattern sector."

[0037] The "servo area SV" may also be referred to as a "zone pattern sector." "At least one piece of data, etc. written to a zone pattern sector" may also be referred to as a "zone pattern sector." A zone pattern sector includes at least one zone servo sector. Hereinafter, the "data pattern of a zone pattern sector" may also be referred to as a "zone data pattern."

[0038] In the example shown in Fig. 3, the servo area SV has zone servo areas ZSV0, ZSV1, and ZSV2. The zone servo areas ZSV0, ZSV1, and ZSV2 are arranged in a staggered manner in the radial direction. The zone servo areas ZSV0, ZSV1, and ZSV2 may be arranged in a stepped manner in the radial direction.

[0039] The zone servo area ZSV2 is located on the inner side of the zone servo area ZSV1. The zone servo area ZSV0 is located on the outer side of the zone servo area ZSV1. For example, the zone servo area ZSV2 is arranged from the inner area IR to the middle area MR, the zone servo area ZSV1 is arranged from the inner area IR to the outer area OR, and the zone servo area ZSV0 is arranged from the middle area MR to the outer area OR. Hereinafter, in a given servo area SV, a given radial area in which a plurality of zone servo areas ZSV are arranged in the circumferential direction may be referred to as a zone servo boundary area, a double servo area, or a double zone servo area ZB.

[0040] In the example shown in FIG. 2, the primary servo areas SVO and the secondary servo areas SVE are alternately arranged at intervals in the circumferential direction. For example, one secondary servo area SVE is arranged between two primary servo areas SVO that are arranged in succession at intervals in the circumferential direction. In other words, one secondary servo area SVE is arranged between two primary servo areas SVO that are arranged in succession at intervals in the circumferential direction. For example, if consecutive numbers are assigned to all servo areas SV of the disk DK in order, the primary servo area SVO corresponds to the odd-numbered servo area SV, and the secondary servo area SVE corresponds to the even-numbered servo area SV. Note that two or more secondary servo areas SVE may be arranged between two primary servo areas SVO that are arranged in succession at intervals in the circumferential direction.

[0041] The primary servo area SVO and the secondary servo area SVE may be composed of only a servo area (hereinafter, sometimes referred to as a normal servo area) that reads and demodulates servo data as a whole. Hereinafter, "reading and demodulating servo data" may be referred to as "servo reading". The primary servo area SVO and the secondary servo area SVE may be composed of, for example, a normal servo area and a servo area (hereinafter, sometimes referred to as a short servo area) that servo reads a circumferential range of servo data that is smaller than the circumferential range of servo data servo read in the normal servo area.

[0042] The media cache M is allocated to the disk DK. However, the media cache M does not have to be located on the disk DK. By using the above-mentioned plurality of servo data, it is possible to position the head HD so as to obtain a predetermined off-track amount, and to detect the amount and direction of the head HD's wobble.

[0043] In the description of this embodiment, the number of zones on the disk DK is three, but the number of zones on the disk DK can be changed in various ways. The number of zones on the disk DK may be 30 to 40. Each zone has multiple bands. For example, each zone has several hundred bands.

[0044] Fig. 4 is a schematic diagram showing three tracks STR and the write head WHD in the user data area U where the shingled recording process is performed on the disk DK shown in Fig. 3. The user data area U is a shingled recording area. In the user data area U, it is permitted to write data sequentially in band units, that is, shingled recording is permitted.

[0045] As shown in Fig. 4, the write head WHD can sequentially write data to the disk DK in the travel direction d2. The read head RHD shown in Fig. 3 can also sequentially read data written to the disk DK in the travel direction d2.

[0046] A direction in which a plurality of tracks STR are continuously shingled-recorded in a direction parallel to the radial direction d1, that is, a direction in which the track STR to be written next is overlapped with the track STR written previously in the radial direction d1, is referred to as an overwrite direction or a recording progress direction. In the band BAe shown in FIG. 4, the overwrite direction is an inward direction, but the overwrite direction may be an outward direction. For example, the overwrite direction applied to multiple bands BA (multiple zones Z) located on the outer side of a specific radial position may be opposite to the overwrite direction applied to multiple bands BA (multiple zones Z) located on the inner side of a specific radial position.

[0047] Band BAe has a plurality of tracks STR, including tracks STRe, STRe+1, and STRe+2. Tracks STRe, STRe+1, and STRe+2 are continuously overwritten in the overwrite direction in the order of their description. Of tracks STRe, STRe+1, and STRe+2, track STRe corresponds to the track on which data is written first, and track STRe+2 corresponds to the track on which data is written last.

[0048] The track STRe has a track center STCe at the center in the radial direction d1 when no other tracks have been overwritten. The track STRe+1 has a track center STCe+1 at the center in the radial direction d1 when no other tracks have been overwritten. The track STRe+2 has a track center STCe+2 at the center in the radial direction d1 when no other tracks have been overwritten.

[0049] In the example shown in Fig. 4, tracks STRe, STRe+1, and STRe+2 are written at a pitch (shingled recording track pitch) STP. The track center STCe of track STRe and the track center STCe+1 of track STRe+1 are separated by a pitch STP in the radial direction d1. The track center STCe+1 of track STRe+1 and the track center STCe+2 of track STRe+2 are separated by a pitch STP in the radial direction d1. Tracks STRe to STRe+2 may be written at different pitches.

[0050] The width in the radial direction d1 of the area of ​​the track STRe where the track STRe+1 is not overwritten is the same as the width in the radial direction d1 of the area of ​​the track STRe+1 where the track STRe+2 is not overwritten. Note that the width in the radial direction d1 of the area of ​​the track STRe where the track STRe+1 is not overwritten may be different from the width in the radial direction d1 of the area of ​​the track STRe+1 where the track STRe+2 is not overwritten.

[0051] In Fig. 4, for convenience of explanation, each track STR is shown in a rectangular shape, but in reality, each track STR is curved along the circumferential direction. Also, each track STR may be wavy extending in the circumferential direction while fluctuating in the radial direction d1. Note that, although three tracks STR are overwritten in Fig. 4, more than three tracks STR may be overwritten.

[0052] The write processing unit 61a can execute the write process by selecting a shingled recording format in which data is written to a plurality of tracks STR overlapping in the radial direction d1 of the disk DK. In the example shown in Fig. 4, the write processing unit 61a sequentially performs shingled recording on tracks STRe to STRe+2 in band BAe toward the inward direction (overwriting direction) at pitch STP.

[0053] The write processing unit 61a writes track STRe+1 inwardly of track STRe at pitch STP, and overwrites track STRe+1 on a part of the inner circumference side of track STRe. The write processing unit 61a writes track STRe+2 inwardly of track STRe+1 at pitch STP, and overwrites track STRe+2 on a part of the inner circumference side of track STRe+1.

[0054] Fig. 5 is a schematic diagram showing three tracks CTR and a write head WHD of the media cache M where normal recording processing of the disk DK shown in Fig. 3 is performed. The media cache M and the system area S shown in Fig. 3 are normal recording areas. In the media cache M and the system area S, it is permitted to write data randomly, that is, normal recording is permitted.

[0055] 5, the media cache M has a plurality of tracks CTR including tracks CTRe, CTRe+1, and CTRe+2. For example, the width (track width) of the tracks CTRe, CTRe+1, and CTRe+2 in the radial direction d1 is the same. Note that the track widths of the tracks CTRe to CTRe+2 may be different from each other.

[0056] The track CTRe has a track center CTCe at the center in the radial direction d1, the track CTRe+1 has a track center CTCe+1 at the center in the radial direction d1, and the track CTRe+2 has a track center CTCe+2 at the center in the radial direction d1. In the example shown in Fig. 4, the tracks CTRe, CTRe+1, and CTRe+2 are written at a pitch (normal recording track pitch) CTP. The track center CTCe of the track CTRe and the track center CTCe+1 of the track CTRe+1 are separated by the pitch CTP. The track center CTCe+1 of the track CTRe+1 and the track center CTCe+2 of the track CTRe+2 are separated by the pitch CTP.

[0057] The track CTRe and the track CTRe+1 are separated by a gap GP. The track CTRe+1 and the track CTRe+2 are separated by a gap GP. The tracks CTRe to CTRe+2 may be written at different pitches. In FIG. 5, for convenience of explanation, each track CTR is shown as a rectangle, but in reality, each track CTR is curved along the circumferential direction. Also, each track CTR may be wavy and extend in the circumferential direction while fluctuating in the radial direction d1.

[0058] The write processing unit 61a can select a normal recording format in which data is written to a plurality of tracks CTR at intervals in the radial direction d1 of the disk DK and execute the write processing. In the example shown in Fig. 4, the write processing unit 61a performs normal recording on the track CTRe or a predetermined sector of the track CTRe in a predetermined area of ​​the disk DK by positioning the write head WHD at the track center CTCe.

[0059] The write processing unit 61a positions the write head WHD at a track center CTCe+1 that is spaced inward from the track center CTCe of the track CTRe by the pitch CTP, and performs normal recording on the track CTRe+1 or a predetermined sector of the track CTRe+1. The write processing unit 61a positions the write head WHD at a track center CTCe+2 that is spaced inward from the track center CTCe+1 of the track CTRe+1 by the pitch CTP, and performs normal recording on the track CTRe+2 or a predetermined sector of the track CTRe+2.

[0060] The write processing unit 61a may normally record tracks CTRe, CTRe+1, and CTRe+2 sequentially in a specified area of ​​the disk DK, or may normally record randomly in a specified sector of track CTRe, a specified sector of track CTRe+1, and a specified sector of track CTRe+2.

[0061] Fig. 6 is a schematic diagram showing an example of data write processing in a disk DK. As shown in Fig. 6, the user data area U has bands BAa, BAb, and BAc. The bands BAa, BAb, and BAc belong to the same zone Ze. In the zone Ze, the bands BAa, BAb, and BAc are intermittently arranged in the overwrite direction in the order of their description.

[0062] The bands BAa and BAb are adjacent to each other in the radial direction d1, and the bands BAb and BAc are adjacent to each other in the radial direction d1. Band BAa includes tracks STRa1, STRa2, STRa3, ..., STRa(x-2), STRa(x-1), and STRax. Tracks STRa1 to STRax are shingled in the overwrite direction in the order of their description. In band BAa, track STRa1 corresponds to the first track to which data is written first, and track STRax corresponds to the last track to which data is written last.

[0063] Band BAb includes tracks STRb1, STRb2, STRb3, ..., STRb(x-2), STRb(x-1), and STRbx. Tracks STRb1 to STRbx are shingled in the overwrite direction in the order of their description. In band BAb, track STRb1 corresponds to the first track to which data is written first, and track STRbx corresponds to the last track to which data is written last.

[0064] Band BAc includes tracks STRc1, STRc2, STRc3, ..., STRc(x-2), STRc(x-1), and STRcx. Tracks STRc1 to STRcx are shingled in the overwrite direction in the order of their description. In band BAc, track STRc1 corresponds to the first track to which data is written first, and track STRcx corresponds to the last track to which data is written last.

[0065] The number of tracks STR in each band BA belonging to the same zone Z is the same. For example, the number of tracks STR in each band BA belonging to zone Ze is the same. In other words, the number of tracks STR in each band BA is fixed for each zone Z.

[0066] Fig. 6 shows tracks CTRx-1 and CTRx. In Fig. 6, tracks CTRx-1 and CTRx are normally recorded in the media cache M or the system area S. Tracks CTRx-1 and CTRx are adjacent to each other in the radial direction d1.

[0067] Fig. 7 is a schematic diagram showing two bands BAa, BAb and one guard band GB in the user data area U shown in Fig. 6. As shown in Fig. 7, the shingled recording method is different from the normal recording method in that a part of the track STR is overwritten, and therefore the MPU 60 manages the tracks in the user data area U in units called bands.

[0068] A guard band GB is generally provided between bands BA adjacent in the radial direction d1. The guard band GB includes a guard track GTR. Unlike the present embodiment, the guard band GB may include a plurality of guard tracks GTR. The guard band GB has a role of suppressing interference between adjacent bands BA. The guard band GB makes it possible to perform shingled recording in units of one band BA. Furthermore, the guard band GB makes it possible to separate the range (band BA) to be written sequentially.

[0069] For example, the track center STCa(x-2) of track STRa(x-2), the track center STCa(x-1) of track STRa(x-1), the track center STCax of track STRax, the track center GTC of the guard track GTR, the track center STCb1 of track STRb1, the track center STCb2 of track STRb2, and the track center STCb3 of track STRb3 are positioned at equal pitch in the radial direction d1.

[0070] The recording capacity of each band BA in the user data area U, excluding the guard band GB, is usually determined in advance based on the specifications required by the user. The MPU 60 can record the same amount of data in each band BA. Generally, the recording capacity of each band BA is 128 MiB or 256 MiB.

[0071] Fig. 8 is a schematic diagram showing three sectors SCe, SC(e+1), and SC(e+2) of one track STRa1 of band BAa shown in Fig. 6. As shown in Fig. 8, each track STR has a plurality of sectors SC. Track STRa1 has a plurality of sectors SC including sectors SCe, SC(e+1), and SC(e+2). Each track STR belonging to the same zone Z has the same number of sectors SC.

[0072] Each sector SC has a length Ls in the circumferential direction of the disk DK. The write head WHD has a width W in the seek direction d4. The width W of each write head WHD falls within a reference range. The width W of each write head WHD varies from one to another.

[0073] Next, a method for setting the band BA will be described. 9 is a schematic diagram showing one band BAe in the user data area U of the disk DK according to the comparative example, and is a diagram for explaining an example in which the adjustment unit 62 does not adjust the number of unused sectors in the band BAe. In FIG. 9, the band BAe is shown as a rectangle, but in reality, the band BAe is curved along the circumferential direction.

[0074] 9, in band BAe, the number of sectors SC in each track STRe is n, the number of tracks STRe is t+1, the number of unused sectors in the sectors SC in band BAe to which no data is written is e, and the difference between n and e is k. Also, the recording capacity of band BAe is Cb, and the recording capacity of each sector SC is Cs.

[0075] The adjustment unit 62 obtains information on the recording capacity Cb, the recording capacity Cs, and the number n of sectors SC. From the recording capacity Cs and the number n of sectors SC, the adjustment unit 62 can calculate information on the linear recording density, which is the recording capacity per inch in the circumferential direction. The linear recording density can be expressed in BPI (bit per inch). The adjustment unit 62 may obtain information on the linear recording density instead of the number n of sectors SC, and calculate the number n of sectors SC from the recording capacity Cs and the information on the linear recording density. The number of tracks STRe per inch in the radial direction d1 is called the track density. Track density can be expressed in TPI (tracks per inch).

[0076] The number of sectors SC in band BAe required to obtain recording capacity Cb is Cb / Cs. Once the number n of sectors SC in one track STRe, i.e., the BPI, is determined, the values ​​of t and k can be calculated using the following formula 1. The relationship between n, e, and k can be expressed by the following formula 2. Cb / Cs=n×t+k (Formula 1) n=e+k (Formula 2)

[0077] The adjustment unit 62 can finally determine the values ​​of t, e, and k based on information on the recording capacity Cb, recording capacity Cs, and the number n of sectors SC. In Fig. 9, the area with the dot pattern is an area in which 128 MiB or 256 MiB of data is recorded by the shingled recording process, and is an area for securing the recording capacity Cb. The area without the dot pattern (blank area) is an unused area. In the shingled recording type, the recording capacity Cb of each band is fixed, so there are unused areas (unused sectors) as shown in the figure.

[0078] In the example of Figure 9, the adjustment unit 62 does not adjust the number of unused sectors in band BAe, so the adjustment unit 62 sets the above n, t, k, and e to the following values ​​based on the determined BPI. n=200 t=100 k=10 e=190

[0079] n > t and e ≥ t. In the example of FIG. 9, it can be seen that there are the above-mentioned number of unused sectors greater than or equal to t in the band BAe. Since there are too many unused sectors in the band BAe, it is difficult to lower the BPI of the band BAe.

[0080] FIG. 10 is a schematic diagram showing one band BAe in the user data area U of the disk DK according to the above embodiment, and is a diagram for explaining an example when the adjustment unit 62 adjusts the number of unused sectors in the band BAe. In FIG. 10, the band BAe is shown in a rectangular shape, but actually, the band BAe is curved along the circumferential direction. In FIG. 10, the above k is a variable. Also, similar to FIG. 9, in FIG. 10, the area with a dot pattern is an area where 128 MiB or 256 MiB of data is recorded by the interleaved recording process, and the blank area is an unused area.

[0081] As shown in FIGS. 10 and 1, the adjustment unit 62 can adjust the first to fourth adjustment values respectively. The first adjustment value is the number n of a plurality of sectors SC in each track STRe of the band BAe. The second adjustment value is the length Ls of each sector SC in the circumferential direction of the disk DK. The third adjustment value is the number t + 1 of a plurality of tracks STRe of the band BAe. The fourth adjustment value is the frequency of the data written to the band BAe.

[0082] The write processing unit 61a can select an interleaved recording format and execute a write process based on the above first to third adjustment values. The adjustment unit 62 can adjust the above first to third adjustment values to make e < t hold. In the present embodiment, the write processing unit 61a can select an interleaved recording format and execute a write process based on the above first to fourth adjustment values. The adjustment unit 62 can adjust the above first to fourth adjustment values to make e < t hold.

[0083] In the example of FIG. 10, there are no unused sectors in band BAe with a number greater than or equal to t. The number e of unused sectors in band BAe can be reduced. Since the BPI of band BAe can be lowered by the amount by which e is reduced, the quality of track STRe can be improved, and the recording quality of data on track STRe can be improved.

[0084] The adjustment unit 62 can adjust the first to third adjustment values in order to further satisfy n > t. In the present embodiment, the adjustment unit 62 can adjust the first to fourth adjustment values in order to satisfy n > t. The adjustment unit 62 can satisfy e < t < n. The adjustment unit 62 can eliminate the relationship of e < n ≤ t. Therefore, the adjustment unit 62 can satisfactorily reduce the number e of unused sectors, and can reduce the number of sectors SC of each track STRe.

[0085] The adjustment unit 62 can finally determine the value of t and tentatively determine the respective numerical values of n, e, and k by acquiring information on the recording capacity Cb, the recording capacity Cs, and the number n of sectors SC.

[0086] Before the adjustment unit 62 adjusts the number of unused sectors in band BAe, if the adjustment unit 62 originally determines that e < t as shown in FIG. 10, the adjustment unit 62 can finally determine each of n, e, and k without changing their numerical values.

[0087] On the other hand, before the adjustment unit 62 adjusts the number of unused sectors in band BAe, if the adjustment unit 62 determines that e ≥ t as shown in FIG. 9, in order to satisfy e < t, the adjustment unit 62 can reduce the numerical value of n, increase the numerical value of k, reduce the numerical value of e, and finally determine each of n, e, and k.

[0088] For example, when reducing the value of n, increasing the value of k, and reducing the value of e, the adjustment unit 62 can reduce the value of n by 1, increase the value of k by t, and reduce the value of e by t. In other words, the state of FIG. 9 can be changed to the state of FIG. 10.

[0089] As described above, in the example of FIG. 10, since the adjustment unit 62 adjusts the number of unused sectors of the band BAe, the adjustment unit 62 sets n, t, k, and e to the following values respectively. n = 199 t = 100 k = 110 e = 89 Note that the adjustment unit 62 has not made an adjustment to change the value of t. Also, the adjustment unit 62 satisfies 1 ≦ e < t.

[0090] Also, for the amount by which the number n of sectors SC can be reduced, the adjustment unit 62 can increase the length Ls of each sector SC and lower the frequency of the data written to the band BAe. By satisfying e < t, the BPI can be set low, and the recording quality can be improved.

[0091] Furthermore, the adjustment unit 62 can adjust the first and second adjustment values based on the characteristics of the write head WHD. The adjustment unit 62 can adjust the first and second adjustment values to larger values as the width W of the write head WHD is larger. That is, as the width W is larger, the area of the write head WHD facing the disk DK becomes larger, and the magnetic field irradiated to the disk DK becomes larger, so that the recording quality can be improved. As a result, it is possible to increase the BPI as the width W is larger. Note that the influence of the width W on the BPI is large, but the influence of the width W on the TPI is small. From the above, it is desirable for the adjustment unit 62 to adjust the first to fourth adjustment values for each head zone (for each write head WHD and for each zone Z).

[0092] According to the magnetic disk drive 1 according to the present embodiment configured as described above, the magnetic disk drive 1 includes a disk DK, a write head WHD, an adjustment unit 62, and a write processing unit 61a. By adopting the tile recording method, it is possible to increase the capacity of the disk DK. In the tile recording method, there is a feature that the capacity of the band BAe is predetermined. The recording capacity Cb of the band BAe in FIG. 9 and the recording capacity Cb of the band BAe in FIG. 10 are the same, for example, 256 MiB each. When viewed from the firmware, there is no difference between the recording capacity Cb of the band BAe in FIG. 9 and the recording capacity Cb of the band BAe in FIG. 10.

[0093] On the other hand, the number of unused sectors of the band BAe in FIG. 9 and the number of unused sectors of the band BAe in FIG. 10 are significantly different. As shown in FIG. 10, by the adjustment by the adjustment unit 62, the number of unused sectors existing in the band BAe is reduced. And in the example of FIG. 10, since the BPI of the band BAe can be adjusted lower and the frequency of the data written to the band BAe can be lowered, the recording quality of the data of the band BAe can be improved.

[0094] Even if the BPI of the band BAe in FIG. 10 is made lower than the BPI of the band BAe in FIG. 9, the recording capacities Cb of these two bands BAe are the same. From the above, it is possible to obtain the magnetic disk drive 1 that can improve the quality of the data recorded on the disk DK while increasing the capacity of the disk DK.

[0095] (Modification example of the above embodiment) Next, this modification example will be described. The magnetic disk drive 1 is configured in the same manner as the magnetic disk drive 1 of the above embodiment except for the configuration described in this modification example. When the number t + 1 of a plurality of tracks STRe of the band BAe is specified in advance, the adjustment unit 62 adjusts the first and second adjustment values respectively, and does not have to adjust the third adjustment value. The write processing unit 61a can select the tile recording format and execute the write processing based on the first and second adjustment values. The adjustment unit 62 can adjust the first and second adjustment values in order to satisfy e < t.

[0096] In this modification, when the number t + 1 of a plurality of tracks STRe of the band BAe is specified in advance, the adjustment unit 62 may adjust the above first, second, and fourth adjustment values respectively. The write processing unit 61a can select a tile recording format and execute write processing based on the above first, second, and fourth adjustment values. The adjustment unit 62 can adjust the above first, second, and fourth adjustment values in order to satisfy e < t.

[0097] The adjustment unit 62 can finally determine the respective numerical values of the above n, e, and k in order to satisfy e < t by acquiring the information on the recording capacity Cb, the recording capacity Cs, and the above t. Also in this modification, the same effects as those of the above embodiment can be obtained.

[0098] Although the embodiments of the present invention have been described, the above embodiments are presented as examples and are not intended to limit the scope of the invention. The above novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. The above embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

[0099] For example, the above-described technology is not limited to a magnetic disk device of a hybrid recording format, and may be applied to a magnetic disk device of a tile recording format.

[0100] As in the above-described embodiment, the adjustment unit 62 satisfies 1 ≦ e < t and provides an unused sector in the band BA. Thereby, even if a sector SC that has failed in writing occurs when performing write processing on the band BA in the tile recording format, the unused sector can be used as an alternative sector. However, it is not essential to provide an unused sector in the band BA. Therefore, the adjustment unit 62 may satisfy 0 ≦ e < t. When e = 0, the BPI of the band BA can be adjusted to be the lowest. [Explanation of symbols]

[0101] 1...magnetic disk device, 60...MPU, 61...read / write processing unit, 61a...write processing unit, 62...adjustment unit, 100...host, 110...system controller, 120...driver IC, 130...head amplifier IC, 140...R / W channel, 150...HDC, DK...disk, L...recording layer, Z...zone, BA...band, STR...track, SC...sector, GB...guard band, GTR...guard track, WHD...write head, W...width, Ls...length, Cb, Cs...recording capacity, n, t, e...number, k...variable, d1...radial direction, d2...traveling direction, d3...rotational direction, d4...seek direction.

Claims

1. a disk having a band containing a plurality of tracks, each of said tracks containing a plurality of sectors; a write head for writing data onto the disk; an adjustment unit that adjusts a first adjustment value, which is the number of the sectors in each of the tracks of the band, a second adjustment value, which is the length of each of the sectors in the circumferential direction of the disk, and a third adjustment value, which is the number of the tracks of the band; a write processing unit capable of selecting a shingled recording type for writing data onto the plurality of tracks in a radial overlapping manner on the disk, and executing a write process based on the first to third adjustment values, If the number of the plurality of tracks in the band is t+1, and the number of unused sectors among the plurality of sectors in the band is e, then the adjustment unit adjusts the first to third adjustment values ​​so as to satisfy e<t. Magnetic disk device.

2. Let the number of the sectors in each of the tracks in the band be n, The adjustment unit further adjusts the first to third adjustment values ​​so as to satisfy n>t.

2. The magnetic disk drive according to claim 1.

3. Let Cb be the recording capacity of the band, Cs be the recording capacity of each of the sectors, and k be a variable. Cb / Cs=n×t+k, n=e+k, The adjustment unit is Obtaining information on the Cb, the Cs, and the n, determining the t finally, and determining the n, the e, and the k provisionally; When it is determined that e<t, each of the n, the e, and the k is finally determined without changing the numerical value; When it is determined that e≧t, in order to establish e<t, the value of n is decreased, the value of k is increased, and the value of e is decreased, and the values ​​of n, e, and k are finally determined.

3. The magnetic disk drive according to claim 2.

4. When the adjustment unit determines that e≧t, the adjustment unit decreases the value of n by 1, increases the value of k by t, and decreases the value of e by t.

4. The magnetic disk drive according to claim 3.

5. when the adjustment unit determines that e≧t, the adjustment unit increases a length of each of the sectors and decreases a frequency of the data written to the band.

5. The magnetic disk drive according to claim 3.

6. The adjustment unit further adjusts a fourth adjustment value which is a frequency of the data, the write processing unit is capable of selecting the shingled recording type and executing a write process based on the first to fourth adjustment values, the adjustment unit adjusts the first to fourth adjustment values ​​so as to satisfy e<t.

2. The magnetic disk drive according to claim 1.

7. a disk having a band containing a plurality of tracks, each of said tracks containing a plurality of sectors; a write head for writing data onto the disk; an adjustment unit that adjusts a first adjustment value, which is the number of the sectors in each of the tracks of the band, and a second adjustment value, which is the length of each of the sectors in a circumferential direction of the disk; a write processing unit capable of selecting a shingled recording type for writing data onto the plurality of tracks in a radial overlapping manner on the disk and executing a write process based on the first and second adjustment values, Let Cb be the recording capacity of the band, Cs be the recording capacity of each of the sectors, n be the number of the sectors in each of the tracks in the band, t+1 be the number of the tracks in the band, k be a variable, and e be the number of unused sectors among the sectors in the band. Cb / Cs=n×t+k, n=e+k, The adjustment unit is Obtaining the information of Cb, Cs, and t, and finally determining n, e, and k so that e<t holds; Magnetic disk device.

8. The adjustment unit is adjusting the first and second adjustment values ​​based on a characteristic of the write head; The larger the width of the write head in the seek direction, the larger the first and second adjustment values ​​can be adjusted to.

8. The magnetic disk drive according to claim 1.

9. The adjustment unit satisfies 1≦e<t.

8. The magnetic disk drive according to claim 1.

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