Method and magnetic disk device

Abstract

The embodiment relates to a method and a magnetic disk device. The method comprises the steps of obtaining, calculating, selecting and distributing. The obtaining means obtaining the result of a quality check associated with the recording quality of a first plurality of sectors included in a first storage area of the disk. The calculation is to calculate a first number, which is the number of sectors corresponding to the capacity obtained by subtracting the set capacity from the actual capacity of the first storage region, on the basis of the set capacity of the first storage region and the set value of the recording density of the first storage region. The selection means that a second number of sectors among the plurality of sectors are selected on the basis of the result. The assignment is to assign an address usable by the host to a group of sectors corresponding to the set capacity and not included in the second number of sectors among the plurality of first sectors.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2024-046278 (filing date: March 22, 2024), the entire contents of which are incorporated herein by reference. Technical Field

[0002] This embodiment relates to a method and a magnetic disk device. Background Art

[0003] Conventionally, a recording method called SMR (Shingled Magnetic Recording) is known in magnetic disk devices. SMR allows the track pitch to be made narrower than the width of the write head, thereby increasing the recording density.

[0004] Regarding magnetic disk devices, there is a demand for not only an improvement in recording density but also an improvement in recording quality. Summary of the Invention

[0005] According to one embodiment, the method includes obtaining, calculating, selecting, and allocating. Acquiring refers to obtaining the results of a quality inspection related to the recording quality of a first plurality of sectors included in a first storage area of ​​a magnetic disk possessed by a magnetic disk device. The first storage area includes a first plurality of tracks to which data is written in an SMR (Shingled Magnetic Recording) manner. A plurality of sectors different from the first plurality of sectors are set in each of the first plurality of tracks. Calculating refers to calculating a first number, which is the number of sectors corresponding to a capacity obtained by subtracting the set capacity from the actual capacity of the first storage area, based on a set capacity of the first storage area and a set value of the recording density of the first storage area. Selecting refers to selecting a second number of sectors from the first plurality of sectors based on the result. The second number is a number greater than 0 and less than the first number. Allocating refers to allocating addresses usable by a host connected to the magnetic disk device to a group of sectors corresponding to the set capacity in the first plurality of sectors that are not included in the second number of sectors.

[0006] According to one embodiment, a method and a magnetic disk device capable of improving recording quality can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0008] Figure 2 This is a diagram showing an example of the structure of a magnetic disk according to the first embodiment.

[0009] Figure 3 It is a diagram for explaining the SMR according to the first embodiment.

[0010] Figure 4 This is a diagram for explaining CMR according to the first embodiment.

[0011] Figure 5 This is a diagram showing an example of a plurality of band areas provided on the magnetic disk according to the first embodiment.

[0012] Figure 6 This is another diagram showing an example of a plurality of band areas provided on the magnetic disk according to the first embodiment.

[0013] Figure 7 This is a diagram showing an example of setting tracks in each band area according to the first embodiment.

[0014] Figure 8 This is a diagram for explaining an example of the relationship between the actual capacity and the set capacity of the band area according to the first embodiment.

[0015] Figure 9 This is a diagram for explaining the area to which LBAs are allocated by the magnetic disk device according to the first embodiment.

[0016] Figure 10 It is a diagram for explaining the inspection device according to the first embodiment.

[0017] Figure 11 This is a flowchart showing an example of the operation of the quality inspection performed by the inspection apparatus according to the first embodiment.

[0018] Figure 12 This is a flowchart showing an example of the operation of the magnetic disk device according to the first embodiment.

[0019] Figure 13 This is a flowchart showing an example of the operation of the quality inspection performed by the inspection device according to the second embodiment.

[0020] Figure 14 This is a flowchart showing an example of the operation of the magnetic disk device according to the second embodiment.

[0021] Figure 15 This is a diagram for explaining the area to which LBAs are allocated by the magnetic disk device according to the second embodiment.

[0022] Description of Reference Numerals

[0023] 1 Magnetic disk device, 2 Host, 3 Inspection device, 11 Magnetic disk, 12 SPM, 13 Ramp, 15 Actuator arm, 22 Magnetic head, 22r Read head, 22w Write head, 23 HDC, 24 Preamplifier, 25 RWC, 26 Processor, 28 FROM, 29 DRAM, 30 SoC, 40 Storage device, 41 Quality information, 100 Recording surface, 110 Storage area, 120 Medium cache area, 130, 130a, 130b Band area, 140 Guard area, 150 Remaining sector group, 160, 165, 170, 171 Areas, 180 Spare sector group. DETAILED DESCRIPTION

[0024] Hereinafter, the method and magnetic disk device according to the embodiments will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0025] (First embodiment)

[0026] Figure 1 This is a diagram showing an example of the configuration of the magnetic disk device 1 according to the first embodiment.

[0027] The magnetic disk device 1 is connected to a host computer 2. The magnetic disk device 1 can receive access commands from the host computer 2. The access commands include write commands and read commands.

[0028] Magnetic disk device 1 includes a magnetic disk 11 having a magnetic layer formed on its surface. Magnetic disk device 1 accesses magnetic disk 11 based on access commands. Access includes writing data and reading data. The access command includes an address indicating a location in the logical address space, which magnetic disk device 1 provides to host computer 2. Host computer 2 specifies the location of the access destination based on the address included in the access command. The address is, for example, an LBA (Logical Block Address). The following description assumes that the address is an LBA.

[0029] Data is written and read by a magnetic head 22. Specifically, the magnetic disk device 1 includes, in addition to the magnetic disk 11, a spindle motor (SPM) 12, a ramp 13, an actuator arm 15, a voice coil motor (VCM) 16, a servo controller (SVC) 21, a magnetic head 22, a hard disk controller (HDC) 23, a preamplifier 24, a read / write channel (RWC) 25, a processor 26, a FROM (Flash Read Only Memory) 28, and a DRAM (Dynamic Random Access Memory) 29.

[0030] The magnetic disk 11 is rotated at a predetermined rotation speed by the SPM 12 coaxially mounted thereon.

[0031] In addition, Figure 1 1 shows one magnetic disk 11. However, the magnetic disk device 1 may include a plurality of magnetic disks 11. When the magnetic disk device 1 includes a plurality of magnetic disks 11, the plurality of magnetic disks 11 are rotated integrally by the SPM 12. A magnetic head 22 is provided for each recording surface of the plurality of magnetic disks 11.

[0032] The SVC 21 is an integrated circuit having a function as a driver for driving the SPM 12 and the VCM 16. The processor 26 controls the rotation of the SPM 12 and the rotation of the VCM 16 via the SVC 21.

[0033] The magnetic head 22 writes to and reads from the magnetic disk 11 through its write head 22w and read head 22r. The magnetic head 22 is mounted on the front end of the actuator arm 15. The magnetic head 22 moves in the radial direction of the magnetic disk 11 via the VCM 16 driven by the SVC 21. Alternatively, a plurality of either the write head 22w or the read head 22r of the magnetic head 22 may be provided relative to a single magnetic head 22.

[0034] When the magnetic disk 11 stops rotating, the magnetic head 22 moves onto the ramp 13. The ramp 13 is configured to hold the magnetic head 22 at a position separated from the magnetic disk 11.

[0035] The preamplifier 24 is an integrated circuit that writes and reads data via the magnetic head 22. During a read operation, the preamplifier 24 amplifies the signal read from the magnetic disk 11 by the magnetic head 22, outputs the amplified signal, and supplies it to the RWC 25. Furthermore, during a write operation, the preamplifier 24 amplifies the signal corresponding to the data to be written supplied from the RWC 25, and supplies the amplified signal to the magnetic head 22.

[0036] The HDC 23 controls data transmission and reception with the host computer 2 via the I / F bus, controls the DRAM 29 , and the like.

[0037] The DRAM 29 is used as a buffer for data transmitted and received with the host 2. For example, the DRAM 29 is used to temporarily store data to be written or data read from the magnetic disk 11.

[0038] The DRAM 29 is used as an operating memory by the processor 26. The DRAM 29 is used as an area for loading firmware programs. The DRAM 29 is also used as a buffer for data transfer between the host 2 and the disk 11.

[0039] The RWC 25 modulates the write target data supplied from the HDC 23 and supplies it to the preamplifier 24. The RWC 25 also performs demodulation including error correction on the signal read from the magnetic disk 11 and supplied from the preamplifier 24, and then outputs the signal to the HDC 23 as digital data.

[0040] The processor 26 is, for example, a CPU (Central Processing Unit). A FROM (Flash Read Only Memory) 28 and a DRAM 29 are connected to the processor 26 .

[0041] The FROM 28 stores a firmware program and various setting information. Alternatively, the firmware program may be stored in the magnetic disk 11 .

[0042] The processor 26 controls the entire magnetic disk device 1 according to the firmware program stored in the FROM 28 or the magnetic disk 11. For example, the processor 26 loads the firmware program from the FROM 28 or the magnetic disk 11 into the DRAM 29 and controls the SVC 21, the preamplifier 24, the RWC 25, the HDC 23, and the like according to the firmware program loaded into the DRAM 29.

[0043] In addition, part or all of the functions of the processor 26 may also be implemented by a hardware circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0044] The HDC 23, RWC 25, and processor 26 form a single integrated circuit, a SoC (System-On-a-Chip) 30. The SoC 30 may include other elements (such as a FROM 28 or a DRAM 29) in addition to these elements. The SoC 30 is an example of a controller.

[0045] Figure 2 This figure shows an example of the structure of the magnetic disk 11 according to the first embodiment. Servo information is written to the magnetic layer formed on the surface of the magnetic disk 11, for example, using a servo writer. Servo information can also be written to the magnetic disk 11 using self-servo writing (SSW). The servo information includes sector / cylinder information, a burst pattern, and a post-code. The SoC 30 uses the magnetic head 22 to read the servo information and performs positioning operations based on the read servo information.

[0046] exist Figure 21 shows radially arranged servo areas SV as an example of the arrangement of servo areas in which servo information is written. A plurality of concentric tracks TR are arranged at predetermined intervals in the radial direction of the magnetic disk 11. A large number of sectors are continuously formed on each track TR. Data is written to and read from each sector by a magnetic head 22.

[0047] There are several types of recording methods, that is, methods for writing data to the magnetic disk 11. These recording methods include SMR (Shingled Magnetic Recording) and CMR (Conventional Magnetic Recording).

[0048] Figure 3 This diagram illustrates SMR in the first embodiment. In SMR, data (denoted as first data) is written to a track TR, and then data (denoted as second data) is written to a radially adjacent track TR. When writing the second data, the second data is written so that it partially overlaps with the first data. In other words, SMR writes data from one of two radially adjacent tracks TR on the magnetic disk 11 so that the data from the other track TR partially overlaps.

[0049] As an example, in Figure 3 Tracks TR#M-1, TR#M, and TR#M+1 are depicted as three tracks TR. Tracks TR#M-1 and TR#M are adjacent to each other. Tracks TR#M and TR#M+1 are adjacent to each other. In this example, data is written in the order of track TR#M-1, track TR#M, and track TR#M+1. The data of track TR#M is written so that a portion of it radially overlaps the data of track TR#M-1. The data of track TR#M+1 is written so that a portion of it radially overlaps the data of track TR#M. That is, according to SMR, the data of one track TR is repeatedly overlapped with a portion of the data of the adjacent track TR to which data has already been written.

[0050] According to SMR, data is written by the above-described method, so the track pitch TP is narrower than the element width (WHw) of the write head 22w of the magnetic head 22. As a result, the recording density can be set high.

[0051] However, SMR is susceptible to ATE (Adjacent Track Erasure) due to its narrow track pitch TP. Therefore, in principle, data for multiple radially continuous tracks TR is updated collectively. The area where multiple tracks TR are collectively updated is called a band area. "Update" can be expressed as "change" or "rewrite."

[0052] In addition, according to SMR, since the data of one track TR is written in a manner that overlaps a portion of the data of the adjacent track TR in which data has already been written, for a plurality of continuous tracks TR, writing can only be performed in any one direction from the inner side to the outer side and from the outer side to the inner side. The radial direction corresponding to the order of writing to such a plurality of radially continuous tracks TR is denoted as the SMR direction. The SMR direction can be the same in all band areas or can be determined for each band area. Below, as an example, it is assumed that the SMR direction is the same in all band areas.

[0053] Figure 4 This diagram illustrates CMR in the first embodiment. As shown in this diagram, according to CMR, the data of each track TR is arranged so that it does not overlap with the data of radially adjacent tracks TR. In other words, CMR writes data so that data of two radially adjacent tracks TR on the magnetic disk 11 do not overlap.

[0054] For example, in Figure 4 In the figure, track TR#N-1, track TR#N, and track TR#N+1 are depicted as three tracks TR. Track TR#N-1 is radially separated from track TR#N. Track TR#N is radially separated from track TR#N+1. In other words, track TR#N-1, track TR#N, and track TR#N+1 are arranged so that data on two adjacent tracks TR do not overlap.

[0055] According to CMR, the track pitch TP is equal to or larger than the element width (WHw) of the write head 22w, so data at any position can be updated. Therefore, according to CMR, random access performance is improved.

[0056] Figure 5 and Figure 6 This is a diagram showing an example of a plurality of band areas provided on the magnetic disk 11 according to the first embodiment.

[0057] The recording surface 100 of the magnetic disk 11, that is, the area where the tracks TR can be arranged, is divided radially into a plurality of storage areas 110. The plurality of storage areas 110 include a media cache area 120 and a plurality of band areas 130. Write-prohibited areas called guard areas 140 are provided between the storage areas 110. Each guard area 140 includes, for example, one or more tracks TR.

[0058] The storage area 110 located radially outermost within the recording surface is designated as a media cache area 120. The media cache area 120 is a storage area used as a temporary storage location for data. For example, data is written to the media cache area 120 using CMR. The location of the media cache area 120 is not limited to the outermost area. Alternatively, two or more media cache areas 120 may be provided on the recording surface.

[0059] Two or more of the plurality of storage areas 110 are set as band areas 130. Multiple tracks TR are provided in each band area 130. Data is written to all tracks TR in each band area 130 using the SMR method. When writing data to each band area 130, data is prohibited from being written from the band area 130 designated as the write destination to an adjacent band area 130 across the guard area 140.

[0060] The LBA is mapped to each band area 130. Thus, each band area 130 is set as the final storage location of data requested to be written by the host 2 (represented as write data).

[0061] As described above, the data stored in each band area 130 is updated on a per-band basis. For example, write data sent from the host 2 is temporarily cached in the DRAM 29. All data in the band area 130 (referred to as "band data"), which is set as the final storage location for the write data cached in the DRAM 29, is transferred to the media cache area 120, for example. The band data is then updated in the media cache area 120 using the write data cached in the DRAM 29. The updated band data is then overwritten in the band area 130. The method of updating per-band area 130 is not limited to this.

[0062] Figure 7 This is a diagram showing an example of setting of the tracks TR in each band area 130 according to the first embodiment.

[0063] exist Figure 7In the example shown, band area 130 includes nine tracks TR, namely, track TR#K through track TR#(K+8). Based on the SMR direction set for band area 130, data is written first to track TR#K. Following track TR#K, data is written to track TR#(K+1), track TR#(K+2), track TR#(K+3), track TR#(K+4), track TR#(K+5), track TR#(K+6), and track TR#(K+7) in that order, with data being written to track TR#(K+8) last.

[0064] The track TR where data is first written to the band area 130, such as track TR#K, is referred to as the head track TR. The track TR where data is last written to the band area 130, such as track TR#(K+8), is referred to as the end track TR.

[0065] In addition, the leading track can be considered as the track TR closest to one of the two radial ends of a band area 130 , and the trailing track can be considered as the track TR closest to the other of the two radial ends of the band area 130 .

[0066] According to SMR, data on one track TR is written so that data partially overlaps with data on an adjacent track TR that has already been written. Therefore, the track width W1 of all tracks TR except track TR#(K+8), namely, tracks TR#K through TR#(K+7), is narrower than the element width WHw of the write head 22w. In contrast, track TR#(K+8) is the last track TR to be written to the band area 130, so the track width W2 of track TR#(K+8) is equal to the element width WHw of the write head 22w. In other words, the track width W2 of track TR#(K+8) is wider than the track width W1 of tracks TR#K through TR#(K+7).

[0067] According to each magnetic head 22, the recording performance has deviations caused by manufacturing deviations. In addition, there are also deviations in the data retention ability in the recording surface of the magnetic disk 11. Thus, the recording surface is divided into multiple zones in the radial direction, and the recording density is set according to each combination of the zone and the magnetic head 22. The recording density of the magnetic disk 11 is defined as TPI (Track Per Inch, number of tracks / inch) and BPI (Bit Per Inch, bit / inch). TPI is the configuration density of the track TR, and BPI is the recording density along the track TR.

[0068] The larger the TPI, the narrower the track width W, and the worse the recording quality. Conversely, the larger the BPI, the worse the recording quality. TPI and BPI are set to maximize recording density while maintaining recording quality above a predetermined level.

[0069] Each band area 130 is included in any partition. Figure 7 In the illustrated band area 130, the track width W1 is determined by the TPI set for the partition that includes the band area 130. However, the track width W2 of track TR#(K+8), the last track TR, is wider than the track width W1 of tracks TR#K through TR#(K+7). Therefore, the recording quality of track TR#(K+8) is higher than that of tracks TR#K through TR#(K+7).

[0070] exist Figure 7 . The write / read direction is the direction in which data is written to and read from each track TR. The magnetic head 22 moves relative to the magnetic disk 11 as the magnetic disk 11 rotates. Therefore, the write / read direction is opposite to the rotation direction of the magnetic disk 11.

[0071] In a single track TR, writing / reading is performed in sectors along the writing / reading direction. Therefore, a band head sector, which is the first sector in the band area 130 to be written, and a band tail sector, which is the last sector in the band area 130 to be written, are determined. The band head sector is contained in track TR#K, which is the first track TR. The band tail sector is contained in track TR#(K+8), which is the last track TR.

[0072] Generally, the storage capacity of each band area 130 is set based on customer specifications. During the manufacture of the magnetic disk device 1, each band area 130 is set so that the storage capacity of each band area 130 is the set value (hereinafter referred to as the set capacity) based on the customer's specifications. In practice, each band area 130 is set per track TR, so the actual storage capacity of each band area 130 (hereinafter referred to as the actual capacity) is slightly larger than the set capacity.

[0073] Figure 8 This is a diagram for explaining an example of the relationship between the actual capacity and the set capacity of the band area 130 according to the first embodiment.

[0074] exist Figure 8, band area 130a and band area 130b are shown, arranged at different radial positions. The shaded area 160 of band area 130a and band area 130b represents a group of sectors where data is written when the set capacity of data is written seamlessly from the leading sector of each band area 130. Area 150 is a group of remaining sectors, generated at the end track TR, corresponding to the capacity obtained by subtracting the set capacity from the actual capacity of the band area 130. Area 150 is denoted as remaining sector group 150. Furthermore, each sector constituting remaining sector group 150 is denoted as a remaining sector.

[0075] The recording density of the band area 130 (i.e., the pair of TPI and BPI) may vary for each partition. Therefore, the size of the remaining sector group 150, i.e., the number of remaining sectors, may vary for each band area 130. Figure 8 In the example shown, the number of remaining sectors in the band area 130a is greater than the number of remaining sectors in the band area 130b.

[0076] Generally speaking, the recording quality in all sectors of a band region 130 is not uniform, and may vary locally due to various reasons. In addition, as mentioned above, the track width W of the last track TR is wider than the track width W of other tracks TR, so the recording quality is also higher than that of the sectors of other tracks TR.

[0077] Therefore, in the first embodiment, the magnetic disk device 1 prohibits the use of sectors with low recording quality. Instead of assigning LBAs to sectors with low recording quality, the magnetic disk device 1 assigns LBAs to the remaining sectors of the last track TR. This allows the use of high-quality sectors of the last track TR instead of the low-quality sectors. This improves the recording quality of the entire band area 130.

[0078] Figure 9 This figure is used to explain the area where LBAs are allocated by the magnetic disk device 1 according to the first embodiment. In this figure, the shaded area 165 is an area consisting of sectors to which LBAs are allocated. The blank areas 170 and 180 are groups of sectors to which no LBAs are allocated.

[0079] In the band area 130a, the area 170 consisting of sectors with low recording quality is not assigned LBAs. Figure 8 The remaining sectors of the remaining sector group 150 constituting the band area 130a are shown, except for Figure 9 LBAs are allocated to all sectors except for the spare sector group 180 shown, which is composed of a predetermined number of spare sectors on the end sector side of the band.

[0080] In the band area 130b, LBAs are not allocated to the area 170 consisting of sectors with low recording quality. Figure 8 The remaining sectors of the remaining sector group 150 constituting the band area 130b are shown, except for Figure 9 LBAs are allocated to all sectors except for the spare sector group 180 shown, which is composed of a predetermined number of spare sectors on the end sector side of the band.

[0081] Furthermore, a spare sector group 180 consisting of a predetermined number of spare sectors is provided on the end sector side of each band area 130. The spare sectors are provided in case a sector becomes difficult to use in the band area 130 after shipment.

[0082] After shipment, if a sector becomes difficult to use from among the sectors to which LBAs are assigned, the SoC 30 uses a spare sector included in the same band area 130 instead of the sector to which LBAs are assigned. Specifically, for example, if a write operation to a sector to which LBAs are assigned (denoted as sector 1) fails a predetermined number of times in a row, the SoC 30 registers sector 1 as a prohibited sector. Furthermore, the SoC 30 does not write to sector 1, but instead restarts the write operation from the sector immediately following sector 1. Since the set capacity of the band area 130 is fixed, an LBA is assigned to a spare sector (denoted as sector 2) within the spare sector group 180 in response to the fact that sector 1 is designated as a prohibited sector, and sector 2 is used as the data storage destination.

[0083] Here, the spare sector group 180 is provided in the band area 130, but it is not necessary to provide the spare sector group 180 in the band area 130. If the spare sector group 180 is not provided in the band area 130, LBAs can be allocated to all sectors of the last track TR of the band area 130.

[0084] In this way, by setting a number of spare sectors greater than 0 in each band area 130, when the number of remaining sectors included in the remaining sector group 150 is set to the first number, LBAs are allocated to the second number of remaining sectors in the first number of remaining sectors, which is a number greater than 0 and less than the first number, instead of allocating LBAs to sectors with low recording quality.

[0085] Inspection of recording quality (hereinafter referred to as quality inspection) is performed by, for example, an inspection device.

[0086] Figure 10 It is a diagram for explaining the inspection device 3 according to the first embodiment.

[0087] The magnetic disk drive 1 is connected to an inspection device 3. The inspection device 3 can have a configuration similar to that of a conventional computer, including a processor and a storage device. The processor of the inspection device 3 inspects the recording quality of all sectors of the magnetic disk 11 connected to the magnetic disk drive 1. The processor of the inspection device 3 generates quality information 41 recording the inspection results of the recording quality and stores the generated quality information 41 in the storage device 40 included in the magnetic disk drive 1. The storage device 40 is not limited to a specific storage device. The storage device 40 can be, for example, the FROM 28 or the magnetic disk 11.

[0088] In addition, Figure 10 In the example shown, one magnetic disk device 1 is connected to the inspection device 3. A plurality of magnetic disk devices 1 may be connected to the inspection device 3. The inspection device 3 may be configured to perform inspections on the plurality of magnetic disk devices 1 in parallel.

[0089] Figure 11 This is a flowchart showing an example of the operation of the quality inspection performed by the inspection device 3 according to the first embodiment.

[0090] The processor of the inspection device 3 performs a quality inspection on all sectors by writing data to and reading data from the magnetic disk device 1 connected to the inspection device 3 ( S101 ).

[0091] For example, the processor of the inspection device 3 compares the write data sent to the magnetic disk device 1 with the read data received from the magnetic disk 11 for each sector, and calculates the number of errors contained in the read data for each sector. The number of errors contained in the read data calculated for each sector is then used as an indicator of the recording quality of each sector.

[0092] Furthermore, the method of quality inspection for all sectors is not limited to the above-described method.

[0093] The processor of the inspection device 3 records the results of the quality inspection of all sectors in the quality information 41 (S102), and stores the quality information 41 in the storage device 40 of the magnetic disk device 1 (S103). Then, the quality inspection operation ends.

[0094] The quality information 41 is not limited to a specific configuration. The quality information 41 may also include an index representing recording quality for each sector. The index representing recording quality may be the number of errors contained in the read data, or may be numerical information calculated based on the number of errors contained in the read data and having multiple levels.

[0095] Figure 12 This is a flowchart showing an example of the operation of the magnetic disk device 1 according to the first embodiment.

[0096] The SoC 30 first sets a plurality of band areas 130 on the magnetic disk 11 based on the set capacity (i.e., the set value of the storage capacity of each band area 130) and the set values ​​of the recording density (TPI and BPI) (S201). The SoC 30 calculates the capacity of each track TR based on the set value of the recording density. Then, the SoC 30 sets the bundle of the plurality of consecutively arranged tracks TR into a single band area 130 for all band areas 130. At this time, the SoC 30 sets each band area 130 so that the size of the remaining remaining sector group 150 of each band area 130 does not exceed the size of a single track TR. Furthermore, the size of the remaining remaining sector group 150 does not necessarily need to be less than the size of a single track TR.

[0097] Next, the SoC 30 selects one of the plurality of set band areas 130 ( S202 ), and the selected band area 130 is represented as a target band area.

[0098] The SoC 30 determines the TPI and BPI of the target band area (S203), and calculates the number Nr of remaining sectors in the target band area, excluding sectors designated as spare sectors (S204). The number of all remaining sectors in the target band area is an example of the first number, and the number Nr is an example of the second number.

[0099] The SoC 30 selects Nr sectors with the lowest quality in the target band area based on the quality information 41 ( S205 ).

[0100] In the process of S205, the SoC 30 may select Nr sectors with the lowest quality from all sectors included in the track TRs from the top track TR to the track TR adjacent to the last track TR among the plurality of tracks TR included in the target band area. This is because the sectors included in the last track TR have a higher recording quality than the recording quality indicated by the quality check result.

[0101] After the process of S205 , the SoC 30 sets the selected Nr sectors as use-prohibited sectors ( S206 ).

[0102] Next, the SoC 30 sequentially allocates LBAs to the sectors starting from the leading sector ( S207 ).

[0103] In the process of S207, the SoC 30 allocates LBAs to each sector in the order in which the sectors are arranged and the LBA values ​​are in ascending order. However, the SoC 30 skips the allocation of LBAs to sectors that are prohibited from use. In other words, the SoC 30 allocates LBAs to the group of sectors included in the band area 130 that are not included in the selected Nr sectors and the number of sectors corresponding to the set capacity. Figure 9 As described above, LBAs are allocated to all sectors except for prohibited sectors and spare sectors.

[0104] The SoC 30 determines whether or not any band area 130 that has not been selected as a target band area remains ( S208 ).

[0105] If there are any band regions 130 that have not been selected as the target band region remaining ( S208 : Yes), the SoC 30 selects one of the band regions 130 that have not been selected as the target band region as the target band region ( S209 ) Then, the control proceeds to S203 .

[0106] When no band area 130 that has not been selected as the target band area remains ( S208 : No), the SoC 30 ends the operation.

[0107] The correspondence between each sector and LBA is recorded in management information in a predetermined non-volatile storage area (e.g., FROM 28) by SoC 30. When an access command is received from host 2 after shipment, SoC 30 can identify the sector corresponding to the LBA included in the access command based on the management information.

[0108] As described above, according to the first embodiment, the SoC 30 calculates the number Nr of remaining sectors corresponding to the capacity obtained by subtracting the set value of the recording density from the set capacity based on the set capacity of the band area 130 and the set value of the recording density of the band area 130 (for example, see Figure 12 S204). SoC 30 selects Nr sectors (for example, referring to Figure 12 S205 of FIG. 20). The SoC 30 allocates LBAs (for example, referring to FIG. 20) to the groups of sectors included in the band area 130, which are not included in the selected Nr sectors and whose number corresponds to the set capacity. Figure 12 S207).

[0109] As a result, the recording quality in the band area 130 is improved, and the recording quality of the magnetic disk device 1 as a whole is improved.

[0110] In the first embodiment, the SoC 30 selects Nr sectors (for example, see Figure 12S205).

[0111] By using sectors of the last track TR having good recording quality instead of the Nr sectors having the lowest recording quality in the group of sectors included in the band area 130 , the recording quality in the band area 130 is improved, and the recording quality of the magnetic disk device 1 as a whole is improved.

[0112] Furthermore, the SoC 30 does not necessarily need to select the Nr sectors with the lowest recording quality. The SoC 30 may be configured to select the Nr sectors from sectors whose recording quality does not satisfy a predetermined level.

[0113] Furthermore, as described above, the SoC 30 may select Nr sectors with the lowest quality from all sectors included in the tracks TR from the top track TR to the track TR adjacent to the last track TR among the plurality of tracks TR included in the band area 130 .

[0114] Thus, the sectors of the last track TR with good recording quality are used instead of the Nr sectors with the lowest recording quality in the group of sectors included in the band area 130. Therefore, the recording quality in the band area 130 is improved, and the recording quality of the magnetic disk device 1 as a whole is improved.

[0115] (Second embodiment)

[0116] In the first embodiment, a quality check is performed on all sectors of the magnetic disk device 1. The quality check is not limited to all sectors. Any quality check result can be used as long as it is related to the recording quality of the sectors included in the band area 130. In the second embodiment, a variation of the quality check will be described.

[0117] For example, in the process of forming a magnetic layer on the surface of the magnetic disk 11, the thickness distribution of the magnetic layer in the circumferential direction may be uneven. In such a case, the recording quality is degraded in the elongated region extending in the radial direction.

[0118] Therefore, in the second embodiment, the inspection device 3 performs a quality inspection on a plurality of sectors included in at least one track TR (hereinafter referred to as the inspection track TR) among the plurality of tracks TR provided on the magnetic disk 11. The SoC 30 of the magnetic disk device 1 selects Nr sectors from a radially extending narrow region (hereinafter referred to as a partial region) that includes the sector with the lowest recording quality among the plurality of sectors included in the inspection track TR.

[0119] Hereinafter, matters different from the first embodiment will be described, while matters similar to the first embodiment will be omitted or briefly described.

[0120] Figure 13This is a flowchart showing an example of the operation of the quality inspection performed by the inspection device 3 according to the second embodiment.

[0121] The processor of the inspection device 3 writes data to and reads data from all sectors included in the inspection track TR of the magnetic disk device 1 connected to the inspection device 3, thereby performing a quality inspection on all sectors included in the inspection track TR (S301).

[0122] Furthermore, at least one track TR among the plurality of tracks TR provided on the recording surface 100 of the magnetic disk 11 is set as a test track TR.

[0123] The processor of the inspection device 3 records the result of the quality inspection in the quality information 41 (S302), and stores the quality information 41 in the storage device 40 of the magnetic disk device 1 (S303). Then, the quality inspection operation ends.

[0124] Figure 14 This is a flowchart showing an example of the operation of the magnetic disk device 1 according to the second embodiment.

[0125] SoC30 executes the following steps in S401 to S404: Figure 12 The same processing is performed as in S201 to S204.

[0126] In the process of S405, the SoC 30 selects Nr sectors within the target band area from the partial area. As previously described, the partial area is a long, narrow region extending in the radial direction and including the sector with the lowest recording quality within the test track TR. For example, the partial area extends from the innermost end of the recording surface 100 to the outermost end of the recording surface 100.

[0127] Alternatively, similar to the process in S205, the SoC 30 may select Nr sectors from all sectors included in the track TR from the top track TR to the track TR adjacent to the last track TR in the partial area. This is because the sectors included in the last track TR have a higher recording quality than the recording quality indicated by the quality inspection result.

[0128] After the process of S405 , the SoC 30 performs the same processes as S206 to S209 in S406 to S409 and ends the operation.

[0129] Figure 15 This diagram illustrates the areas to which LBAs are assigned in the magnetic disk device 1 according to the second embodiment. As shown in this figure, area 170, a group of radially arranged sectors, is determined to have low recording quality and is not assigned LBAs. However, since the recording quality of sectors included in the last track TR is relatively high, LBAs are assigned to area 171, which is the sector included in the last track TR.

[0130] As described above, according to the second embodiment, the quality inspection is performed on a plurality of sectors included in at least one track TR among the plurality of tracks TR provided on the magnetic disk 11. The SoC 30 of the magnetic disk device 1 selects Nr sectors from a radially extending elongated region (hereinafter referred to as a partial region) that includes the sector with the lowest recording quality among the plurality of sectors included in the inspection track TR.

[0131] The recording quality of the entire magnetic disk device 1 can be improved based on the results of quality inspection of some sectors among all sectors provided on the magnetic disk 11. Since the quality inspection targets not all sectors provided on the magnetic disk 11, the time required for the quality inspection is shortened.

[0132] In addition, in the second embodiment, the SoC 30 may also select Nr sectors with the lowest quality from all sectors included in the tracks TR from the top track TR to the track TR adjacent to the last track TR among the multiple tracks TR included in the band area 130.

[0133] Thus, the sectors of the last track TR with good recording quality are used instead of the Nr sectors with the lowest recording quality in the group of sectors included in the band area 130. Therefore, the recording quality in the band area 130 is improved, and the recording quality of the magnetic disk device 1 as a whole is improved.

[0134] According to the first embodiment and the second embodiment, the magnetic disk device 1 can exhibit the following characteristics. That is, the number of sectors to which no LBA is assigned, included in the last track TR, is the same in the plurality of band areas 130. Figure 9 In the example shown, the same number of spare sectors is set for the band area 130a and the band area 130b. In each of the band areas 130a and 130b, LBAs are assigned to the remaining sectors included in the last track TR, excluding the spare sectors. Therefore, the number of sectors included in the last track TR of the band area 130a that do not have LBAs assigned is the same as the number of sectors included in the last track TR of the band area 130b that do not have LBAs assigned.

[0135] In the examples described in the first and second embodiments, all of the multiple storage areas 110 provided on the recording surface 100 of the magnetic disk 11, except for the media cache area 120, are used as band areas 130 in which data is written using the SMR method. The techniques of the first and second embodiments are also applicable to magnetic disk devices in which a mixture of band areas 130 in which data is written using the SMR method and areas in which data is written using the CMR method are present in the multiple storage areas 110.

[0136] Furthermore, the techniques of the first and second embodiments are also applicable to a magnetic disk device that can switch the recording method between SMR and CMR during operation. In such a magnetic disk device, when the SoC sets a band area for writing data in the SMR method, it performs a Figure 12 The processing of S203 to S207 shown, or Figure 14 The processing of S403 to S407 is shown.

[0137] In the examples described in the first and second embodiments, the inspection device 3 performs quality inspection, and the SoC 30 of the magnetic disk device 1 obtains the quality inspection result from the quality information 41 (for example, see Figure 12 S205 and Figure 14 The quality inspection result can also be obtained by performing a quality inspection through SoC30. For example, SoC30 can also be configured to perform Figure 11 or Figure 13 A series of actions shown.

[0138] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways and can be omitted, replaced, or modified without departing from the spirit of the invention. These embodiments and their variations are intended to be within the scope and spirit of the invention and are included in the invention described in the claims and their equivalents.

Claims

1. A method comprising: obtaining a quality inspection result related to recording quality of a first plurality of sectors, the first plurality of sectors being included in a first storage area of ​​a magnetic disk included in the magnetic disk device, the first storage area including a first plurality of tracks to which data is written using an SMR method, each of the first plurality of tracks being provided with a different plurality of sectors from the first plurality of sectors; calculating a first number, based on a set capacity of the first storage area and a set value of a recording density of the first storage area, the first number being the number of sectors corresponding to a capacity obtained by subtracting the set capacity from an actual capacity of the first storage area; selecting a second number of sectors from the first plurality of sectors based on the result, the second number being a number greater than 0 and less than the first number; as well as Addresses usable by a host connected to the magnetic disk device are allocated to a group of sectors corresponding to the set capacity, which are not included in the second number of sectors, among the first plurality of sectors.

2. The method according to claim 1, the result being a result of a quality check of all sectors of the first plurality of sectors, The selection is to select the second number of sectors having the lowest recording quality among the first plurality of sectors.

3. The method according to claim 1, The magnetic disk is provided with a second plurality of tracks including the first plurality of tracks. The result is a result of quality inspection of a second plurality of sectors of a plurality of sectors included in one track of the second plurality of tracks, The options include: The second number of sectors included in a partial area is selected. The partial area is an area extending in the radial direction of the magnetic disk and includes sectors having the lowest recording quality among the second plurality of sectors.

4. The method according to any one of claims 1 to 3, The direction of writing data to the first plurality of tracks in the SMR method is set to be from the first track to the second track, the first track being the track closest to one radial end of the first storage area among the first plurality of tracks, and the second track being the track closest to the other radial end of the first storage area among the first plurality of tracks, The selection is to select the second number of sectors from the third plurality of sectors, The third plurality of sectors are a group of sectors included in the third plurality of tracks from the first track to the third track. The third track is a track adjacent to the second track among the first plurality of tracks.

5. The method according to any one of claims 1 to 3, further comprising: The second number is obtained by subtracting a set number greater than 0 from the first number.

6. A magnetic disk device comprising: A magnetic disk having a first storage area and a second storage area, wherein the first storage area includes a plurality of second tracks among a plurality of first tracks each having a plurality of sectors, and the second storage area includes a plurality of third tracks among the plurality of first tracks that are different from the plurality of second tracks; magnetic heads; and a controller that uses the magnetic head to write data to the plurality of second tracks in an SMR manner, and uses the magnetic head to write data to the plurality of third tracks in the SMR manner, The number of sectors contained in the second track to which data is last written in the write operation for writing the multiple second tracks in the SMR manner, which are not assigned addresses usable by the host, is consistent with the number of sectors contained in the third track to which data is last written in the write operation for writing the multiple third tracks in the SMR manner, which are not assigned addresses usable by the host.

Images