Method, device and computer equipment for improving data recovery efficiency of solid state disk

Abstract

The application relates to a solid state disk data recovery efficiency improving method, device, computer equipment and storage medium, wherein the method comprises the following steps: creating and maintaining a physical page position table for recording last writing positions of each physical block in the memory; updating the last writing position recorded in the physical page position table whenever the physical block is written; recording the last writing physical page position of the replaced physical block on a NAND system area when the writing point physical block switches; loading the last writing physical page position record of each physical block from the NAND system area when power failure occurs; and recovering the physical page position table according to the last writing physical page position of each physical block. The application greatly improves the data recovery efficiency.

Description

Technical Field

[0001] This invention relates to the field of solid-state drive (SSD) technology, and in particular to a method, apparatus, computer device, and storage medium for improving SSD data recovery efficiency. Background Technology

[0002] SSDs (Solid State Drives) have been widely used in various applications and are gradually replacing traditional HDDs (Hard Disk Drives) in the PC market, providing users with a better experience in terms of reliability and performance. Internal data storage in SSDs primarily relies on NAND flash memory. With the evolution of media technology, from SLC to MLC / TLC / QLC… and finally NAND, storage density and performance have increased significantly. However, due to the characteristics of the media, data can be corrupted in certain scenarios, such as high temperatures, prolonged storage, and physical wear and tear (PE). In such cases, various data recovery methods are needed to ensure data integrity.

[0003] Currently, media manufacturers offer a method for data recovery by adjusting the read reference voltage (bias voltage parameter) to address various error scenarios. As manufacturing processes evolve, the number of scenarios to be addressed increases, leading to the development of more and more read reference voltage adjustment methods. In particular, the reread parameters differ significantly when data is written to different physical pages within a physical block. If each adjustment parameter is tried sequentially during data recovery, read performance will drastically degrade. Therefore, efficient data recovery is one of the key design considerations within SSDs. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, computer equipment, and storage medium for improving the data recovery efficiency of solid-state drives (SSDs) in response to the aforementioned technical problems.

[0005] A method for improving data recovery efficiency from solid-state drives (SSDs), the method comprising:

[0006] Create and maintain a physical page location table in memory to record the last write location of each physical block;

[0007] The last write position recorded in the physical page location table is updated whenever a physical block is written.

[0008] When a physical block is switched at a write point, the location of the last written physical page of the physical block to be replaced is recorded in the NAND system area;

[0009] When a power failure occurs, the physical page location record of the last written physical block is loaded from the NAND system area;

[0010] The physical page location table is restored based on the last physical page location written to each physical block.

[0011] In one embodiment, the method further includes:

[0012] When a NAND read triggers a reread error correction, the last physical block written to the physical page location table in memory is queried, and the corresponding reread parameters are selected to initiate a reread.

[0013] In one embodiment, the step of querying the last written physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction further includes:

[0014] The physical page location table is looked up based on the physical block number where the NAND read error occurred, and the last physical page written to the physical block is obtained.

[0015] The NAND reread table is queried based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios.

[0016] The bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios are used to initiate rereading in sequence until the data verification is correct.

[0017] In one embodiment, before the step of querying the physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction, the method further includes:

[0018] The NAND controller identifies whether the data is correct based on the verification information attached during writing and determines whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

[0019] A device for improving the efficiency of solid-state drive data recovery, the device comprising:

[0020] A creation module is used to create and maintain a physical page location table in memory to record the last write location of each physical block;

[0021] The update module is used to update the last write position recorded in the physical page location table whenever a physical block is written.

[0022] The recording module is used to record the last written physical page position of the physical block to be replaced on the NAND system area when the physical block of the write point is switched.

[0023] A loading module is used to load the last written physical page location records of each physical block from the NAND system area when a power failure occurs.

[0024] A recovery module is used to recover the physical page location table based on the last written physical page location of each physical block.

[0025] In one embodiment, the device further includes:

[0026] The reread module is used to query the physical page location table of each physical block in memory and select the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction.

[0027] In one embodiment, the reread module is further configured to:

[0028] The physical page location table is looked up based on the physical block number where the NAND read error occurred, and the last physical page written to the physical block is obtained.

[0029] The NAND reread table is queried based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios.

[0030] The bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios are used to initiate rereading in sequence until the data verification is correct.

[0031] In one embodiment, the device further includes:

[0032] The judgment module is used by the NAND controller to identify whether the data is correct based on the verification information attached during writing, and to determine whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

[0033] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the methods described above.

[0034] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the above methods.

[0035] The aforementioned methods, devices, computer equipment, and storage media for improving SSD data recovery efficiency introduce a last-written physical page table (LSP table) for each physical block within the SSD. This table is dynamically maintained in memory, and when a physical block is replaced, the LSP page information is stored in the NAND system data area, enabling recovery after an abnormal power outage. Using this table, when an error occurs while reading any data and requires rereading for error correction, the location of the LSP page for that physical block can be obtained. Then, based on the parameters of the corresponding LSP page group provided by the manufacturer, rereading and error correction can be performed, significantly reducing the number of attempts and improving data error correction efficiency. Attached Figure Description

[0036] Figure 1 A schematic diagram illustrating error correction and rereading in traditional solid-state drives (SSDs).

[0037] Figure 2 This is a flowchart illustrating a method for improving solid-state drive data recovery efficiency in one embodiment;

[0038] Figure 3 This is a flowchart illustrating a method for improving solid-state drive data recovery efficiency in another embodiment;

[0039] Figure 4 A schematic diagram illustrating a physical page location table that records the last write location for one embodiment;

[0040] Figure 5 This is a schematic diagram illustrating error correction and rereading of a solid-state drive in one embodiment;

[0041] Figure 6 This is a structural block diagram of a solid-state drive data recovery efficiency improvement device in one embodiment;

[0042] Figure 7 This is a structural block diagram of a solid-state drive data recovery efficiency improvement device in another embodiment;

[0043] Figure 8 This is a structural block diagram of a solid-state drive data recovery efficiency improvement device in another embodiment;

[0044] Figure 9 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] like Figure 1The diagram illustrates the traditional SSD error correction and retry process, including the following steps: When the host randomly accesses NAND data, it receives a command from the front end, which is then converted into a physical address via the SSD's internal mapping table. The NAND controller initiates a read operation on the NAND. The NAND loads the corresponding data and returns it to the NAND controller. The NAND controller can identify whether the data is correct based on the verification information attached during writing (typically ECC Parity). When the number of erroneous bits is within a certain range (e.g., 160 bits of error per KB of data), it can be corrected. When the data error exceeds a certain range, the data cannot be directly corrected. In this case, the NAND read reference voltage needs to be adjusted, and NAND Read Retry operations are executed sequentially until the data error correction is successful or all Retry operations are completed without success.

[0047] Specifically, the following table shows a typical NAND data error triggering a read retry table.

[0048]

[0049] Index: Different Retry configuration indexes.

[0050] Retry Configuration: Different bias voltage configurations during retries are used to adjust the internal read reference voltage of the NAND flash memory, thereby outputting different data.

[0051] Reliability failure scenarios: The NAND failure scenarios that this Retry configuration can withstand, such as data failure caused by long-term data retention, failure caused by low-temperature writing and high-temperature reading, failure caused by PE wear exceeding specifications, etc.

[0052] Last write position of a physical block: This corresponds to the last physical location written to the current physical block (group). Due to the mutual influence of the NAND structure within the physical block, the data distribution differs at different write positions, resulting in different repair parameters (Retry configuration) for various reliability scenarios.

[0053] As NAND media becomes increasingly complex, the scenarios for reliability failures are also increasing, and the different bias voltage parameters corresponding to the last written pages are also becoming more numerous. When an error occurs while reading NAND data, if the last physical page written to that physical block is unknown, it is necessary to try each page sequentially from the NAND Read Retry Table, which is extremely time-consuming and leads to severe performance degradation.

[0054] Based on this, this solution provides a method to improve the efficiency of solid-state drive data recovery, which aims to reduce the number of attempts to reread parameters and improve data error correction efficiency.

[0055] In one embodiment, such as Figure 2 As shown, a method for improving the efficiency of solid-state drive data recovery is provided, the method including:

[0056] Step 202: Create and maintain a physical page location table in memory to record the last write location of each physical block;

[0057] Step 204: Update the last write position recorded in the physical page location table whenever a physical block is written.

[0058] Step 206: When the physical block of the write point is switched, the last written physical page position of the physical block to be replaced is recorded on the NAND system area.

[0059] Step 208: When a power failure occurs, load the physical page location records of the last written physical blocks from the NAND system area;

[0060] Step 210: Restore the physical page location table based on the last physical page location written to each physical block.

[0061] In this embodiment, a method for improving the efficiency of solid-state drive data recovery is provided. The method maintains a physical page location table (last_page_table) in memory that records the last written physical page location of each physical block (group); the table is updated in memory in real time as physical blocks are written.

[0062] When the physical block (group) at the current write point is switched, the last physical page position (block_last_page_record) of the physical block (group) to be replaced is recorded on the NAND system area.

[0063] When a power failure occurs, each physical block (group) is loaded from the NAND system area and finally written to the physical page record (block_last_page_record). Then, each physical block (group) in memory is restored and finally written to the physical page location table (last_page_table).

[0064] In one embodiment, the method further includes: when a NAND read triggers a reread error correction, querying the physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread.

[0065] When a NAND read triggers an error-correcting read, the last physical block (group) in memory is queried and written to the physical page location table (last_page_table), and the corresponding reread parameters are selected to initiate a reread.

[0066] For specific details, please refer to Figure 4The diagram shows a physical page location table of the last written location of the imported record.

[0067] In this embodiment, a method for tracking the last written pages of each physical block (group) within the SSD is introduced, which allows for the selection of an accurate set of Retry parameters when triggering data repair reread, thus greatly reducing data recovery time.

[0068] For ease of explanation, this example illustrates the writing of a single DIE / physical block at any given time. In reality, SSDs may perform parallel writing of multiple DIEs / physical blocks (groups) to improve performance, but this is achieved through physical block binding (physical blocks of multiple DIEs are bound to a super physical block, physical block 0 of DIE 0 / 1 / 2... is bound to super physical block 0, and so on). The same method can be used for tracking / optimization.

[0069] 4.1 Maintain a table in memory showing the last physical page location of each physical block (group), denoted as last_page_table. Its index is the number of each physical block (group), and its value is the number of the last physical page written to the corresponding physical block (group).

[0070] 4.2. The NAND flash memory contains at least two regions: User Data and System Data.

[0071] 4.3 NAND User Data: Stores user data.

[0072] When writing data internally to an SSD, one physical block (group) is allocated at a time, and the data is written sequentially to each physical page. Typically, a new physical block (group) is only written after the entire physical block (group) has been written. However, in some scenarios, such as insufficient data for error handling / garbage collection, a switch may occur before a physical block (group) is full. In this case, the SSD internally closes the physical block currently being written (corresponding to its last written page, but not the last page of the physical block, such as page 255) and reallocates a new blank physical block (group) for writing.

[0073] Therefore, during the operation of an SSD, there are some physical blocks (groups) that have completed data writing but are not full. When reading data from these blocks triggers data repair and rereading, it is necessary to accurately determine the position of the last page written.

[0074] 4.4 NAND System Data: Stores the internal system data of the SSD.

[0075] Specifically, when a physical block (group) closes data writing, a record block_last_page_record(block_index, last_written_page) is recorded, where block_index is the number of the physical block (group) and last_written_page is the number of the last physical page written.

[0076] The individual physical blocks (groups) inside an SSD are generally very large, such as tens to hundreds of MB. Each time a new 16KB page record is added, the impact on performance is extremely low.

[0077] When an SSD powers on, it rebuilds the last_page_table in memory by loading the block_last_page_record stored in the system data area. During SSD operation, this table is updated in real time, and when a switch occurs between currently written physical blocks (groups), the last written physical page information for the corresponding physical block (group) is written to the NAND system data area. Based on this last_page_table, when an error occurs while reading data from any physical block, the corresponding last written physical page can be found based on the physical block number. This allows for querying the NAND Retry Table and selecting the appropriate bias voltage parameter table for rereading and repair, significantly improving data recovery efficiency.

[0078] In the above embodiment, a last-written physical page table is introduced within the SSD for each physical block. This table is dynamically maintained in memory, and when a physical block is replaced, the last-written page information is stored in the NAND system data area, allowing for recovery after an abnormal power outage. Using this table, when an error occurs while reading any data and requires rereading for error correction, the location of the last-written page of that physical block can be obtained. Then, based on the parameters of the corresponding last-written page group provided by the manufacturer, rereading and error correction can be performed, significantly reducing the number of attempts and improving the efficiency of data error correction.

[0079] In one embodiment, such as Figure 3 As shown, a method for improving the efficiency of solid-state drive (SSD) data recovery is provided. This method includes the following steps: when NAND reads trigger reread error correction, the steps of querying the last written physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread also include:

[0080] Step 302: Based on the physical block number of the NAND read error, look up the physical page location table to obtain the last physical page written to the physical block;

[0081] Step 304: Query the NAND reread table based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios.

[0082] Step 306: Initiate rereading sequentially using the bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios until the data verification is correct.

[0083] In one embodiment, before the step of querying the physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread when a NAND read triggers reread error correction, the method further includes:

[0084] The NAND controller identifies whether the data is correct based on the verification information attached during writing and determines whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

[0085] Specifically, refer to Figure 5 The diagram shown illustrates error correction and rereading on a solid-state drive. The implementation process is as follows:

[0086] 5.1. Receive commands from the front end and convert them into physical addresses through the SSD's internal mapping table.

[0087] 5.2 The NAND controller initiates a read operation on the NAND.

[0088] 5.3 The NAND loads the corresponding data and returns it to the NAND controller.

[0089] 5.4 The NAND controller can identify whether the data is correct based on the verification information attached during writing (typically ECC Parity). When the number of erroneous bits in the data is within a certain range (e.g., 160 bits of error per 1KB of data), it can be corrected. When the data error exceeds a certain range, the data cannot be directly corrected and needs to be reread for error correction.

[0090] 5.5 When rereading and correcting errors, based on the physical block number of the NAND read that caused the error, look up the last_page_table to obtain the last physical page last_page of that physical block.

[0091] 5.6. Based on the last_page, query the NAND Retry Table to obtain the corresponding bias voltage parameter set: Best_Retry_Set, which contains the bias voltage parameters under various reliability failure scenarios when the last physical page written to the corresponding physical block is last_page.

[0092] 5.7. Based on Best_Retry_Set, initiate a reread using the bias voltage parameters for each reliability failure scenario in sequence: set the NAND bias voltage, read the data, verify, and exit until the data verification is correct.

[0093] In this embodiment, when a reread is initiated due to a read error, the optimal reread parameters can be selected based on the last physical page written to the corresponding physical block, which greatly improves the efficiency of data recovery.

[0094] It should be understood that, although Figures 1-5 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figures 1-5 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0095] In one embodiment, such as Figure 6 As shown, a solid-state drive (SSD) data recovery efficiency improvement device 600 is provided, the device comprising:

[0096] Creation module 601, the creation module is used to create and maintain a physical page location table in memory to record the last write location of each physical block;

[0097] Update module 602, the update module is used to update the last write position recorded in the physical page location table whenever a physical block is written;

[0098] Recording module 603 is used to record the last written physical page position of the physical block to be replaced on the NAND system area when the physical block of the write point is switched.

[0099] Loading module 604 is used to load the last written physical page position record of each physical block from the NAND system area when a power failure occurs.

[0100] Recovery module 605, the recovery module is used to recover the physical page location table according to the physical page location last written to each physical block.

[0101] In one embodiment, such as Figure 7 As shown, a solid-state drive data recovery efficiency improvement device 600 is provided, which further includes:

[0102] The reread module 606 is used to query the physical page location table of each physical block in memory and select the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction.

[0103] In one embodiment, the reread module 606 is further configured to:

[0104] The physical page location table is looked up based on the physical block number where the NAND read error occurred, and the last physical page written to the physical block is obtained.

[0105] The NAND reread table is queried based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios.

[0106] The bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios are used to initiate rereading in sequence until the data verification is correct.

[0107] In one embodiment, such as Figure 8 As shown, a solid-state drive data recovery efficiency improvement device 600 is provided, which further includes:

[0108] The judgment module 607 is used by the NAND controller to identify whether the data is correct based on the verification information attached during writing, and to determine whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

[0109] For specific limitations regarding devices for improving SSD data recovery efficiency, please refer to the limitations on methods for improving SSD data recovery efficiency mentioned above, which will not be repeated here.

[0110] In one embodiment, a computer device is provided, the internal structure of which can be shown as follows: Figure 9 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for improving the efficiency of solid-state drive data recovery.

[0111] Those skilled in the art will understand that Figure 9The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0112] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps in the various method embodiments described above.

[0113] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the various method embodiments described above.

[0114] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0115] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0116] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for improving the efficiency of solid-state drive data recovery, the method comprising: Create and maintain a physical page location table in memory to record the last write location of each physical block; The last write position recorded in the physical page location table is updated whenever a physical block is written. When a physical block is switched at a write point, the location of the last written physical page of the physical block to be replaced is recorded in the NAND system area; When a power failure occurs, the physical page location record of the last written physical block is loaded from the NAND system area; The physical page location table is restored based on the last physical page location written to each physical block; When a NAND read triggers a reread error correction, the last physical block written to the physical page location table in memory is queried and the corresponding reread parameters are selected to initiate a reread. The physical page location table is looked up based on the physical block number where the NAND read error occurred, and the last physical page written to the physical block is obtained. The NAND reread table is queried based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios. The bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios are used to initiate rereading in sequence until the data verification is correct.

2. The method for improving data recovery efficiency of solid-state drives according to claim 1, characterized in that, Before the step of querying the physical page location table of each physical block in memory and selecting the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction, the method further includes: The NAND controller identifies whether the data is correct based on the verification information attached during writing and determines whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

3. A device for improving the efficiency of solid-state drive data recovery, characterized in that, The device includes: A creation module is used to create and maintain a physical page location table in memory to record the last write location of each physical block; The update module is used to update the last write position recorded in the physical page location table whenever a physical block is written. The recording module is used to record the last written physical page position of the physical block to be replaced on the NAND system area when the physical block of the write point is switched. A loading module is used to load the last written physical page location records of each physical block from the NAND system area when a power failure occurs. The recovery module is used to recover the physical page location table based on the last written physical page location of each physical block; The reread module is used to query the physical page location table of each physical block in memory and select the corresponding reread parameters to initiate a reread when NAND read triggers reread error correction. The reread module is also used for: The physical page location table is looked up based on the physical block number where the NAND read error occurred, and the last physical page written to the physical block is obtained. The NAND reread table is queried based on the last written physical page to obtain the corresponding bias voltage parameter set, which includes bias voltage parameters under various reliability failure scenarios. The bias voltage parameters included in the bias voltage parameter set for various reliability failure scenarios are used to initiate rereading in sequence until the data verification is correct.

4. The solid-state drive data recovery efficiency improvement device according to claim 3, characterized in that, The device further includes: The judgment module is used by the NAND controller to identify whether the data is correct based on the verification information attached during writing, and to determine whether the number of data errors is within a preset range. If the data errors exceed the preset range, the data cannot be directly corrected and needs to be reread for error correction.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method of claim 1 or 2.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method of claim 1 or 2.

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