Magnetic disk device
By controlling the circuitry in the disk device to pre-move the read/write head to the target storage area and change the recording mode, the problem of insufficient write performance when changing the recording mode is solved, achieving fast data writing and efficient recording mode switching.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KK TOSHIBA
- Filing Date
- 2023-01-10
- Publication Date
- 2026-07-14
AI Technical Summary
Existing disk devices suffer from insufficient write performance when the recording mode changes, especially with poor random access performance in SMR mode. Furthermore, the frequent radial movement of the read/write head required when changing the recording mode leads to low write efficiency.
When a recording mode change command is received, the control circuit moves the magnetic head to the storage area of the target tape in advance and performs a recording mode change before receiving a write command, thereby reducing or avoiding radial movement of the magnetic head and improving write performance.
It enables rapid data writing after a change in recording mode, improving the write performance of the disk device, especially when changing from SMR to CMR or vice versa, reducing the head movement distance and time, and improving writing efficiency.
Smart Images
Figure CN117746919B_ABST
Abstract
Description
[0001] This application enjoys priority based on Japanese Patent Application No. 2022-149153 (filed on September 20, 2022). This application incorporates the entire contents of that basic application by reference. Technical Field
[0002] This embodiment relates to a disk drive. Background Technology
[0003] In recent years, disk devices have been developed that can switch between multiple recording methods. These methods may include, for example, SMR (Shingled Magnetic Recording) or CMR (Conventional Magnetic Recording). Summary of the Invention
[0004] Embodiments of the present invention provide a disk device with high write performance.
[0005] According to one embodiment, the disk drive includes a disk, a read / write head, and a control circuit. The disk has a plurality of first storage areas arranged radially. Each of the plurality of first storage areas is capable of changing its recording mode. Upon receiving a first command instructing a change in the recording mode of one of the plurality of first storage areas, the control circuit changes the recording mode of a second storage area that is that first storage area according to the first command, and moves the read / write head onto the second storage area before receiving a second command. Attached Figure Description
[0006] Figure 1 This is a diagram illustrating an example of the structure of a disk device according to an implementation method.
[0007] Figure 2 This is a diagram illustrating an example of the structure of a disk involved in an implementation method.
[0008] Figure 3 This is a schematic diagram used to illustrate the SMR method of the implementation method.
[0009] Figure 4 This is a schematic diagram used to illustrate the CMR method of the implementation method.
[0010] Figure 5 This is a schematic diagram illustrating an example of multiple bands disposed on a disk in an implementation method.
[0011] Figure 6This is a flowchart illustrating an example of how a disk device in an embodiment changes the recording mode of a tape from SMR to CMR.
[0012] Figure 7 This is a flowchart illustrating an example of how a disk device in an embodiment changes the recording mode of a tape from CMR mode to SMR mode.
[0013] Label Explanation
[0014] 1. Disk device; 11. Disk; 11a. Servo zone; 11b. Track; 12. Spindle motor; 13. Ramp; 15. Actuator arm; 21. Motor driver; 22. Head; 22r. Read element; 22w. Write element; 23. HDC; 24. Preamplifier; 25. RWC; 26. Processor; 27. RAM; 28. FROM; 29. Buffer memory; 30. Control circuit; 40. Host; 110. Storage area; 120. Media cache area; 130. Tape. Detailed Implementation
[0015] Hereinafter, the disk device according to the embodiments will be described in detail with reference to the accompanying drawings. However, this invention is not limited to these embodiments.
[0016] (Implementation Method)
[0017] Figure 1 This is a diagram illustrating an example of the structure of the disk device 1 according to an embodiment.
[0018] Disk device 1 is connected to host 40. Disk device 1 can receive access commands such as write commands or read commands from host 40. In addition to access commands, disk device 1 can also receive commands indicating changes to the recording mode. Recording modes and changes to recording modes will be described later.
[0019] The disk device 1 includes a disk 11. The disk device 1 writes data to the disk 11 and reads data from the disk 11 according to access commands.
[0020] Data writing and reading are performed via the read / write head 22. Specifically, in addition to the disk 11, the disk device 1 also includes a spindle motor 12, a motor driver 21, a read / write head 22, an actuator arm 15, a voice coil motor (VCM) 16, a ramp 13, a preamplifier 24, a read / write channel (RWC) 25, a hard disk controller (HDC) 23, a buffer memory 29, and a processor 26.
[0021] The disk 11 rotates at a predetermined speed around a rotation axis via a spindle motor 12. The rotation of the spindle motor 12 is driven by a motor driver 21.
[0022] The read / write head 22 writes and reads data from the disk 11 using its write element 22w and read element 22r. The read / write head 22 is mounted on the front end of the actuator arm 15. The read / write head 22 moves radially along the disk 11 via the VCM 16 driven by the motor driver 21. When the disk 11 stops rotating, the read / write head 22 moves onto the ramp 13.
[0023] When reading data from disk 11, preamplifier 24 amplifies the signal read by read head 22 from disk 11 and outputs it to RWC 25. Additionally, preamplifier 24 amplifies the signal corresponding to the data to be written from RWC 25 and provides it to read head 22.
[0024] HDC23 controls data transmission and reception between the HDC23 and the host 40 via the I / F bus, controls the buffer memory 29, and performs error correction on the read data.
[0025] The buffer memory 29 is used as a cache for data transmitted and received between the host 40 and the host 40. For example, the buffer memory 29 is used to store data before writing the data of the write object to the disk 11.
[0026] The buffer memory 29 is, for example, composed of a volatile memory capable of high-speed operation. The type of memory constituting the buffer memory 29 is not limited to a specific type. The buffer memory 29 may be composed of, for example, DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).
[0027] RWC25 encodes and modulates the data to be written from HDC23 and provides it to preamplifier 24. Additionally, RWC25 encodes and demodulates signals read from disk 11 and provided by preamplifier 24, and outputs them as digital data to HDC23.
[0028] The processor 26 is, for example, a CPU (Central Processing Unit). RAM 27, FROM (Flash Read Only Memory) 28, and buffer memory 29 are connected to the processor 26.
[0029] RAM 27 is composed of, for example, DRAM or SRAM. RAM 27 is used by the processor 26 as its working memory. RAM 27 is used as an area for loading firmware (program data) and as an area for temporarily storing various management data.
[0030] FROM 28 is a non-volatile memory. Processor 26 performs overall control of disk device 1 according to firmware pre-stored in non-volatile areas such as FROM 28 and disk 11. For example, processor 26 loads firmware from FROM 28 or disk 11 into RAM 27, and executes control of motor driver 21, preamplifier 24, RWC 25, HDC 23, etc. according to the loaded firmware.
[0031] Furthermore, the structure including processor 26, HDC23, and RWC25 can also be considered as control circuit 30. Control circuit 30 may also include other elements such as RAM 27, FROM 28, or buffer memory 29. Alternatively, control circuit 30 may not include RWC25.
[0032] Figure 2 This diagram illustrates an example of the structure of the disk 11 according to the implementation method. For example, servo information is written to the magnetic layer formed on the surface of the disk 11 using a servo writer or similar means before shipment. The servo information includes sector / cylinder information, burst pattern (string pattern), and post code. The sector / cylinder information provides the servo number in the circumferential and radial directions of the disk 11. The burst pattern provides the position deviation of the read / write head 22 from the position indicated by the servo number. The post code is data used to correct for RRO (Repeatable Run Out). The control circuit 30 uses the read / write head 22 to read the servo information and performs seek and tracking operations based on the read servo information. The seek operation is the action of moving the read / write head 22 radially. The tracking operation is the action of holding the read / write head 22 on the target track. Furthermore, servo information can also be written to the disk 11 after shipment via self-servo write (SSW).
[0033] exist Figure 2 The diagram shows a radially arranged servo partition 11a as an example of a servo partition configuration in which servo information has been written. Multiple concentric tracks 11b are arranged radially on the disk 11 at predetermined intervals. A large number of sectors are continuously formed circumferentially on each track 11b. Data is written to and read from each sector using the read / write head 22.
[0034] As a recording method, that is, a method of writing data to disk 11, there are multiple recording methods. These multiple recording methods include SMR and CMR.
[0035] Figure 3This is a schematic diagram used to explain the SMR method of the implementation. SMR is a method in which, when writing data to a certain track (referred to as first data) and then writing data to a track radially adjacent to that track (referred to as second data), the data is written to each track in such a way that a portion of the second data overlaps with a portion of the first data. That is, according to SMR, the data is written in such a way that a portion of the data on one of two radially adjacent tracks of the disk 11 overlaps with the data on the other of those two tracks.
[0036] As an example, in Figure 3 The diagram depicts tracks #M-1, #M, and M+1 as three tracks 11b. Tracks #M-1 and #M are adjacent to each other. Tracks #M and #M+1 are adjacent to each other. In this example, data is written in the order of track #M-1, track #M, and track M+1. Data on track #M is written such that a portion of it radially overlaps with the data on track #M-1. Data on track #M+1 is written such that a portion of it radially overlaps with the data on track #M. That is, according to SMR, data on one track 11b is repeatedly overlapped with a portion of the data on adjacent tracks 11b that have already been written.
[0037] According to SMR, data is written using the method described above, therefore, the track pitch TP is narrower than the core width (WHw) of the writing element 22w of the magnetic head 22. As a result, the recording density is increased. That is, according to SMR, the storage capacity can be increased compared to CMR described later.
[0038] However, according to SMR, the track pitch TP is narrower than the core width WHw of the write element 22w. Therefore, when a portion of the data in multiple tracks is updated (in other words, rewritten), the data in tracks adjacent to the updated data is corrupted. To prevent data corruption, according to SMR, the data of multiple tracks including the updated portion is updated together. The region including the multiple tracks being updated together is called a band. Because of this update method described above, random access performance deteriorates compared to CMR, which will be discussed later.
[0039] Figure 4 This is a schematic diagram illustrating the CMR method of the implementation. As shown in this figure, according to CMR, the data on each track is configured so that it does not overlap with the data on radially adjacent tracks. In other words, CMR is a method of writing data between two radially adjacent tracks of disk 11 in a manner in which they do not overlap.
[0040] For example, in Figure 4The document describes tracks #N-1, #N, and N+1 as three tracks 11b. Tracks #N-1 and #N are arranged radially separate. Tracks #N and #N+1 are also arranged radially separate. That is, tracks #N-1, #N, and N+1 are configured such that the data of two adjacent tracks do not overlap.
[0041] According to CMR, the track pitch TP is the same as or larger than the core width (WHw) of the write element 22w, thus enabling data updates at any location. Consequently, according to CMR, the storage capacity is smaller than SMR, but conversely, the random access performance is higher.
[0042] Disk device 1 can perform data writing in either SMR or CMR mode. The recording modes that disk device 1 can perform are not limited to SMR and CMR modes. Disk device 1 can also be configured to perform data writing in any recording mode other than SMR and CMR modes. Alternatively, disk device 1 can be configured to perform data writing in any number of recording modes, replacing one or both of SMR and CMR modes. Here, as an example, disk device 1 is configured to perform data writing in both SMR and CMR modes.
[0043] The recording method change is performed on a predetermined unit of storage area. Here, as an example, the recording method change is set to be performed on a unit of tape.
[0044] Figure 5 This is a schematic diagram illustrating an example of multiple strips disposed on disk 11 in an implementation method.
[0045] The recording surface of disk 11, that is, the area where tracks 11b can be configured, is radially divided into multiple storage regions 110. The multiple storage regions 110 include a media cache region 120 and multiple stripes 130. Between the storage regions 110 are areas called protection regions that prevent data writing, but... Figure 5 The illustration of the protected area is omitted.
[0046] The storage area 110, located radially outward (i.e., the outermost side) within the recording surface, is designated as the media buffer area 120. The media buffer area 120 is a storage area capable of temporarily storing data. However, the location of the media buffer area 120 is not limited to this. The number of media buffer areas 120 provided on the recording surface is not limited to one. Alternatively, no media buffer area 120 may be provided on the recording surface.
[0047] Additionally, four strips 130 are provided on the recording surface to serve as multiple strips 130. In other words, the four strips 130 are arranged radially. Furthermore, the number of strips 130 provided on the recording surface is not limited to this.
[0048] The control circuit 30 changes the recording mode according to tape 130. Specifically, the recording mode change is achieved through software settings changes, such as altering the configuration of all tracks 11b within tape 130, which is the target of the recording mode change. The control circuit 30 clears the configuration settings of the tracks 11b before the recording mode change and sets the track 11b configuration according to the changed recording mode. For tape 130 after the recording mode change, the control circuit 30 performs seek and tracking operations according to the changed track 11b configuration.
[0049] Additionally, the control circuit 30 executes a change in recording mode based on a command received from the host 40 indicating a change in recording mode. The command indicating the change in recording mode is recorded as a change command. The change command may include the specified recording mode to be changed and the band 130 of the recording mode to be changed. The band 130 of the recording mode to be changed is recorded as object band 130.
[0050] Furthermore, when the disk device 1 can use two recording modes, the change command may not necessarily explicitly include the recording mode of the target to be changed. The control circuit 30 may also be configured to interpret the change command as a command for changing the recording mode of the object band 130 from the currently set recording mode to another recording mode of the two recording modes.
[0051] Furthermore, if the recording method of the object band 130, to which data has already been written, is changed, the control circuit 30 is configured such that the data cannot be read after the recording method change. That is, if the recording method is changed, data written to the object band 130 before the recording method change is considered erased.
[0052] As a method of using the disk device 1 with a high probability of execution, the following method can be considered: The recording mode of a certain band 130 containing unwanted data is changed, and new data is written to the band 130 whose storage capacity has been completely changed to be usable due to the change in recording mode. In this embodiment, when the control circuit 30 changes the recording mode of the target band 130 according to a change command, it changes the recording mode and moves the read / write head 22 onto the target band 130 so that new data can be written to the disk 11 as early as possible. That is, when the control circuit 30 changes the recording mode of the target band 130 according to a change command, it moves the read / write head 22 onto the target band 130 before receiving other new commands, including a write command, from the host 40 after the update command. Therefore, when the disk device 1 receives a write command to write data to the target band 130 after the update command, radial movement of the read / write head 22 corresponding to the write command is not required, or the distance of such movement can be suppressed. As a result, it is possible to quickly begin writing data to the object band 130 using the magnetic head 22, and the write performance is improved.
[0053] Next, the operation of the disk device 1 according to the embodiment will be described. Here, it will be described in two cases: changing the recording mode of a device with 130 from SMR mode to CMR mode and changing the recording mode of a device with 130 from CMR mode to SMR mode.
[0054] Figure 6 This is a flowchart illustrating an example of the operation of a disk device 1 according to an embodiment when changing a recording mode with 130 from SMR mode to CMR mode.
[0055] When the control circuit 30 receives a change command that designates a band 130 as object band 130 and indicates that the recording mode of object band 130 is changed from SMR mode to CMR mode (S101), the control circuit 30 changes the recording mode of object band 130 from SMR to CMR according to the change command (S102).
[0056] Then, the control circuit 30 controls the VCM16 via the motor driver 21, thereby moving the magnetic head 22 onto the object strip 130 (S103).
[0057] Furthermore, the execution order of the processes S102 and S103 is not limited to this. The control circuit 30 can also execute the processes S102 and S103 in parallel. In addition, the timing of the start of the process S103 can be earlier than the timing of the start of the process S102.
[0058] Next, when the control circuit 30 receives a new command (that is, the next command after the change command) from the host 40 (S104), it determines whether the new command is a write command that indicates that data is to be written to the object tape 130 (S105).
[0059] In the case that the new command is a write command indicating that data is to be written to the object tape 130 (S105: Yes), the control circuit 30 controls the VCM16 via the motor driver 21, thereby fine-tuning the position of the magnetic head 22 onto the magnetic track 11b of the writing destination (S106).
[0060] Furthermore, the processing in S106 can sometimes be skipped. For example, if the position of the read / write head 22 after the processing in S103 coincides with the track 11b of the writing destination, the control circuit 30 skips the processing in S106.
[0061] Sometimes a miniature actuator, such as a piezoelectric element, is provided at the front end of the actuator arm 15, which enables fine adjustment of the position of the magnetic head 22 by means of the miniature actuator. When the actuator arm 15 has such a structure, in the process of S106, the motor driver 21 can also finely adjust the position of the magnetic head 22 by means of the action of the miniature actuator without changing the motor position of VCM16.
[0062] When the read / write head 22 is positioned on the track 11b of the write destination, the control circuit 30 begins writing data to the disk 11 using the read / write head 22 (S107). Then, when the writing is complete (S108), the series of actions ends.
[0063] If the new command is not a write command that instructs the writing of data to object 130 (S105: No), the control circuit 30 executes the new command (S109), and the series of actions ends.
[0064] Figure 7 This is a flowchart illustrating an example of the operation of a disk device 1 according to an embodiment when changing a recording mode with 130 from CMR mode to SMR mode.
[0065] When the control circuit 30 receives a change command that designates a band 130 as object band 130 and indicates that the recording mode of object band 130 is changed from CMR mode to SMR mode (S201), it changes the recording mode of object band 130 from CMR to SMR according to the change command (S202).
[0066] Then, the control circuit 30 controls the VCM16 via the motor driver 21, thereby moving the magnetic head 22 to the first track 11b to be written in the track 11b within the target tape 130 (S203).
[0067] As described above, according to the SMR method, the writing order is determined for the multiple tracks 11b contained in a band 130. Therefore, the track 11b that is written first within the target band 130 is uniquely determined. In S203, the control circuit 30 moves the read / write head 22 to the track 11b that is written first.
[0068] Furthermore, the execution order of the processes S202 and S203 is not limited to this. The control circuit 30 can also execute the processes S202 and S203 in parallel. In addition, the timing of the start of the process S203 can be earlier than the timing of the start of the process S202.
[0069] Next, when the control circuit 30 receives a new command (that is, the next command after the change command) from the host 40 (S204), it determines whether the new command is a write command that indicates that data is to be written to the object tape 130 (S205).
[0070] If the new command is a write command indicating that data is to be written to object 130 (S205: Yes), the control circuit 30 begins to use the read / write head 22 to write data to disk 11 (S206).
[0071] Through the process in S203, the magnetic head 22 is moved in advance to the track 11b to be written first. Therefore, in S206, the control circuit 30 can start writing without moving the magnetic head 22.
[0072] When the writing is complete (S207), the series of actions ends.
[0073] If the new command is not a write command that instructs the writing of data to object 130 (S205: No), the control circuit 30 executes the new command (S208), and the series of actions ends.
[0074] As described above, according to the embodiment, when the control circuit 30 receives a change command indicating a change in the recording mode of a tape 130, it changes the recording mode of the specified tape 130 according to the change command, and moves the magnetic head 22 onto the tape 130 before receiving the next command.
[0075] Therefore, when the disk device 1 receives a write command to write data to the target band 130 after an update command, it is possible to eliminate the need for radial movement of the read / write head 22 corresponding to the write command, or to suppress the distance of such movement. As a result, data writing to the target band 130 using the read / write head 22 can begin quickly, improving write performance.
[0076] Furthermore, according to the embodiment, when the received change command is an instruction to change the recording mode of the object tape 130 to SMR mode, the control circuit 30 changes the recording mode of the object tape 130 to SMR mode and moves the magnetic head to the first track 11b written in the object tape 130.
[0077] Therefore, when the control circuit 30 receives a write command indicating that the object band 130 should be written, it can start writing from the track 11b where the magnetic head 22 is located at that point in time.
[0078] That is, the control circuit 30 can immediately begin writing in accordance with the write command without moving the read / write head 22 before writing begins. As a result, writing performance is improved.
[0079] In addition, the control circuit 30 can also move the magnetic head 22 onto the object tape 130 when changing the recording mode of the object tape 130 from SMR to CMR, just as when changing the recording mode of the object tape 130 from CMR to SMR.
[0080] Furthermore, according to the embodiment, if the received change command is an instruction to change the recording mode of the object tape 130 to CMR mode, and the subsequently received command is a write command to write to the object tape 130, the control circuit 30 moves the magnetic head 22 to the magnetic track 11b of the write destination in the object tape 130 and starts writing data.
[0081] The control circuit 30 moves the read / write head 22 onto the target strip 130 before receiving a write command, thus suppressing the movement distance of the read / write head 22 corresponding to the write command. As a result, write performance is improved.
[0082] Furthermore, in the above description, the recording method has been changed on a per-tape basis. The disk device 1 may also be configured such that the recording method is changed on a per-multiple-tape basis.
[0083] Several embodiments of the present invention have been described above, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These new embodiments can be implemented in a wide variety of other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.
Claims
1. A disk drive, comprising: A disk having a plurality of first storage areas arranged radially, each containing a plurality of tracks and capable of changing the recording mode between a first mode and a second mode, wherein the first mode is a mode in which data of two radially adjacent tracks of the disk are written in an overlapping manner, and the second mode is a mode in which data of two radially adjacent tracks of the disk are written in a non-overlapping manner. Magnetic head; and A control circuit, upon receiving a first command from the host indicating a change in the recording mode of one of a plurality of first storage areas, changes the recording mode of a second storage area, which is one of the first storage areas, between the first mode and the second mode according to the first command, and moves the read / write head to the second storage area whose recording mode has been changed according to the first command, before receiving a second command, which is another new command, after the first command.
2. The disk drive according to claim 1, According to the first method, the order in which data is written is determined for the multiple tracks contained in the third storage region, which is the first storage region using the first method, such that the first track among the multiple tracks contained in the third storage region is written first. When the first command is an instruction to change the recording mode of the second storage area to the first mode, the control circuit changes the recording mode of the second storage area to the first mode, and moves the magnetic head to the first track among the multiple tracks before receiving the second command.
3. The disk drive according to claim 2, When the control circuit receives the second command, which is an instruction to write data to the second storage area, it starts writing data from the first track.
4. The disk drive according to claim 1, When the first command is a command instructing the recording mode of the second storage area to be changed to the second mode, the control circuit receives the second command, and the second command is a command instructing the writing of data to the second storage area, and causes the magnetic head to move to the write destination track in the second storage area to start writing data.