TWI768737B - Skipped data clean method and data storage system - Google Patents

Abstract

A skipped data clean method and a data storage system are disclosed. The method includes: receiving data clean command from a host system, wherein the data clean command is configured to clean data belonging to a target logical range; and performing a skipped data clean operation in response to the data clean command. The skipped data clean operation includes: writing default data to a plurality of non-sequential logical block addresses within the target logical range.

Description

Jump data clearing method and data storage system

The present invention relates to a data clearing technology, and more particularly, to a skip data clearing method and a data storage system.

Generally, data stored in a memory device can be erased in a variety of ways. For example, the most common and fastest way to clear data is by modifying or clearing the mapping relationship between specific logical block addresses and physical block addresses. However, this data clearing method does not really clear the data, and there is a security risk in practice. Alternatively, it is also possible to issue a clear command of the entire disk or a clear command of a specified logical range to the memory device, so that the memory device can overwrite the random data on the entire disk or within the specified logical range, so as to actually clear the data. Effect.

However, whether it is a full-disk erasure or a data erasure within a specified logical range, the memory device defaults to perform sequential write. In practice, such large-scale sequential writing tends to quickly exhaust the cache area that is used by default in the memory device, thereby causing the data clearing speed of the memory device to drop significantly in the middle and later stages.

The present invention provides a skip data clearing method and data storage system, which can improve the data clearing efficiency of a memory device.

Embodiments of the present invention provide a skip data clearing method, which is used in a memory device. The skip data clearing method includes: receiving a data clear command from a host system, wherein the data clear command is used to clear data belonging to a target logic range; and in response to the data clear command, executing a skip data clear operation. The skip data clearing operation includes writing preset data to a plurality of discrete logical block addresses within the target logical range.

Embodiments of the present invention further provide a data storage system, which includes a host system and a memory device. The memory device is coupled to the host system. The host system is used for transmitting a data clearing command to the memory device. The data clearing instruction is used to clear the data belonging to the target logic range. In response to the data clearing command, the memory device is configured to perform a skip data clearing operation. The skip data clearing operation includes writing preset data to a plurality of discrete logical block addresses within the target logical range.

Based on the above, after receiving the data clearing command corresponding to the target logical range from the host system, the memory device can automatically perform the skip data clearing operation. In particular, the skip data clearing operation includes writing preset data to a plurality of discrete logical block addresses within the target logical range. Thereby, the data clearing efficiency of the memory device can be effectively improved.

FIG. 1 is a schematic diagram of a data storage system according to an embodiment of the present invention. Referring to FIG. 1 , the data storage system 10 includes a host system 11 and a memory device 12 . The host system 11 can be any type of computer system. E.g. The host system 11 can be a notebook computer, a desktop computer, a smart phone, a tablet computer, an industrial computer, or the like. The memory device 12 is coupled to the host system 11 and used to store data from the host system 11 . For example, memory device 12 may include a solid state drive, a pen drive, or other type of non-volatile memory storage device.

The host system 11 can be connected via a Serial Advanced Technology Attachment (SATA) interface, a high-speed peripheral component connection interface (Peripheral Component Interconnect Express, PCI Express), a Universal Serial Bus (USB), or other types of connection interfaces Electrically connected to the memory device 12 . Thus, the host system 11 can store data to and/or read data from the memory device 12 .

The memory device 12 may include a connection interface 121 , a memory module 122 and a memory controller 123 . The connection interface 121 is used to connect the memory device 12 to the host system 11 . For example, the connection interface 121 may support connection interface standards such as SATA, PCI Express, or USB. The memory device 12 can communicate with the host system 11 via the connection interface 121 . In one embodiment, the connection interface 121 also supports the NVM Express (NVMe) standard.

The memory module 122 is used for storing data. The memory module 122 may include a rewritable non-volatile memory module. The memory module 122 includes a memory cell array. For example, the memory module 122 may include a single-level cell (SLC) NAND-type flash memory module (ie, a flash memory module in which one memory cell can store 1 bit), multiple Multi Level Cell (MLC) NAND flash memory modules (ie, a memory cell can store 2 bits of flash memory modules), Triple Level Cell (TLC) NAND type flash memory module (ie, a memory cell can store 3 bits of flash memory module), Quad Level Cell (Quad Level Cell, QLC) NAND type flash memory module (ie , a memory cell can store a 4-bit flash memory module) or other memory modules with similar characteristics. In addition, the memory cells in the memory module 122 store data by changing the threshold voltage.

The memory controller 123 is connected to the connection interface 121 and the memory module 122 . The memory controller 123 may be used to control the memory device 12 . For example, the memory controller 123 can control the connection interface 121 and the memory module 122 for data access and data management. For example, the memory controller 123 may include a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers , Application Specific Integrated Circuits (ASIC), Programmable Logic Device (PLD) or other similar devices or combinations of these devices.

In one embodiment, the memory controller 123 is also referred to as a flash memory controller. In one embodiment, the memory module 122 is also referred to as a flash memory module. The memory module 122 can receive the command sequence from the memory controller 123 and access the data stored in the memory cells according to the command sequence.

FIG. 2 is a schematic diagram of a management memory module according to an embodiment of the present invention. Please refer to FIG. 1 and FIG. 2 , the memory module 122 includes a plurality of physical units 201(1)-201(B). Each of the physical units 201(1)-201(B) includes a plurality of memory cells and is used for non-volatile storage of data. For example, an entity unit may include one or more entity pages, one or more entity blocks, or other entity management units. Multiple memory cells in a physical page can be programmed simultaneously to store data. Multiple memory cells in a physical block can be erased simultaneously.

In one embodiment, the memory controller 123 may divide the physical units 201( 1 ) to 201(A) into the storage area 210 and divide the physical units 201(A+1) to 201(B) into the idle area 220 . When new data from the host system 11 needs to be stored, one or more physical units in the idle area 220 can be selected to store this data and allocated to the storage area 210 .

In one embodiment, the memory controller 123 may configure a plurality of logical units 202( 1 ) to 202(C) to map the physical units in the storage area 210 . A logical unit may include one or more logical block addresses (Logical Block Address, LBA).

In one embodiment, the memory controller 123 may record the mapping relationship between the logical unit and the physical unit in a mapping table (also referred to as a logical-to-physical mapping table). For example, the mapping table may include a Flash Translation Layer (FTL) mapping table or a similar mapping table. The memory controller 123 can access the memory module 122 according to the mapping information in the mapping table.

In one embodiment, the physical units 201(1)-201(A) in the storage area 210 can store valid data and invalid data. Valid data is the latest data belonging to a logical unit. Invalid data is not the latest data belonging to any one logical unit. For example, if the host system 11 writes a new data into a certain logical unit and overwrites the old data originally stored in this logical unit (ie, updates the data belonging to this logical unit), the data stored in the storage area 210 will be The new data is the latest data belonging to the logical unit and will be marked as valid, while the overwritten old data may still be stored in the storage area 210 but marked as invalid.

In one embodiment, if the data belonging to a logical unit is updated, the memory controller 123 can change the mapping relationship between the logical unit and the physical unit storing the old data belonging to the logical unit from the mapping removed from the table. At the same time, the memory controller 123 can establish a new mapping relationship between the logical unit and the physical unit storing the latest data belonging to the logical unit and store the new mapping relationship in the mapping table.

In one embodiment, the memory controller 123 may associate one or more physical units that do not store valid data to the idle area 220 and may erase these physical units. The data stored in the erased physical unit will be erased.

In one embodiment, the memory controller 123 may receive write commands from the host system 11 . The write command may instruct data from host system 11 to be stored at one or more logical block addresses. The memory controller 123 can write the data carried by the write command to the logical block address specified by the write command according to the write command. It should be noted that in the process of writing the data carried by the write command to the logical block address specified by the write command, the memory controller 123 may instruct the memory module 122 to write the write command The carried data is stored in one or more physical units. Then, the memory controller 123 can map the logical block address specified by the write command to a physical unit for storing the data carried by the write command. At the same time, the memory controller 123 may store the mapping relationship between the logical block address specified by the write command and the physical unit for storing the data in the mapping table. Thereby, the memory controller 123 can complete the data writing operation corresponding to the writing command.

In one embodiment, the host system 11 may transmit a data clear command to the memory device 12 . The memory controller 123 may receive the data clear command from the host system 11 . The data clearing command is used to clear data belonging to a certain logical range (also called the target logical range). In response to this data clearing command, the memory controller 123 may perform a skip data clearing operation. It should be noted that the skip data clearing operation includes writing default data to a plurality of discontinuous logical block addresses within the target logical range. For example, the default data may include random data or meaningless data not belonging to the user data.

In one embodiment, the data clear command may include at least one write command. The at least one write command may instruct to write the default data to all logical block addresses within the target logical range. It should be noted that although the data clear command (or write command) is to instruct to write the default data to all logical block addresses within the target logical range, the memory controller 123 does not The default data is not written to all logical block addresses within the target logical range completely in accordance with the instructions of the host system 11 .

In one embodiment, in a skip data clear operation, the memory controller 123 may write the default data to a certain logical block address (also referred to as the first logical block) within the target logical range block address) and another logical block address (also called the second logical block address). There are P logical block addresses between the first logical block address and the second logical block address. The P logical block addresses are not written into the default data, and P is a positive integer.

In other words, in the skip data clearing operation, the memory controller 123 can skip part of the logical block addresses in the target logical range in a skip write manner, and only write to a part of the target logical range. Non-consecutive logical block addresses perform skip data writing. In this way, the overwriting speed of the old data within the target logical range can be accelerated.

FIG. 3 is a schematic diagram of logical block addresses to be cleared by a data clearing command according to an embodiment of the present invention. Referring to FIG. 3 , in one embodiment, the data clear command from the host system 11 of FIG. 1 instructs to write the default data to consecutive 9 logical block addresses N˜N+8. That is to say, for the host system 11, the host system 11 wants to instruct the memory device 12 to perform sequential writing of the preset data to the logical block addresses N~N+8 through the data clear command. , thereby clearing the old data in the logical range covering logical block addresses N~N+8. In response to the data clear command, the memory controller 123 may perform a skip data clear operation for logical block addresses N~N+8 within the logical range.

FIG. 4 is a schematic diagram illustrating a skip data clearing operation according to an embodiment of the present invention. Referring to FIG. 4 , following the embodiment of FIG. 3 , in the skip data clearing operation, the memory controller 123 can skip logical block addresses N+1 to N+3 and N+ within the logical range. 5~N+7, and only perform skip data writing to logical block addresses N, N+4 and N+8 within the logical range to write the default data to the logical block Addresses N, N+4 and N+8.

It should be noted that, in the embodiment of FIG. 4 , it is assumed that P is 3 (that is, there are three skipped logical block addresses between two logical block addresses that are continuously written). However, in another embodiment, P may also be other positive integers (eg, 1 or 4, etc.).

In one embodiment, the same or similar to the skip data clearing operation shown in FIG. 4 is used to skip over some old data in the target logical range, so as to destroy the old data in the target logical range. In addition, the skip data clearing operation can effectively reduce the amount of data to be written compared to completely overwriting all data or all logical block addresses within the target logical range.

In one embodiment, in the skip data clearing operation, before data writing (ie, data overwriting) is performed to a certain logical block address within the target logical range, the memory controller 123 may also determine that Whether this logical block address has valid data stored. If valid data is stored in the logical block address, the memory controller 123 can write the default data to the logical block address to overwrite the valid data. However, if the logical block address does not store valid data, the memory controller 123 may skip the logical block address without writing the default data to the logical block address. In this way, meaningless data overwriting behavior can be reduced.

In one embodiment, in the skip data clearing operation, before data writing (ie, data overwriting) is performed to a certain logical block address within the target logical range, the memory controller 123 may also determine that Whether the mapping information for this logical block address exists in the mapping table. If the mapping information of the logical block address exists in the mapping table (that is, the mapping table contains the mapping information related to the logical block address), it means that the logical block address is currently stored and valid material. Therefore, the memory controller 123 can write the default data to this logical block address to overwrite the valid data. However, if the mapping information of the logical block address does not exist in the mapping table (that is, the mapping table does not record the mapping information related to the logical block address), it means that the logical block address is currently No valid data saved. Therefore, the memory controller 123 can skip the logical block address without writing the default data to the logical block address.

In one embodiment, the host system 11 may send an enable command to the memory device 12 before receiving the data clear command from the host system 11 . The memory controller 123 may receive the enable command from the host system 11 . In response to the enable command, the memory controller 123 may enable the skip data clearing operation. For example, the memory controller 123 may set a control parameter corresponding to the skip data clearing operation to an enabled state according to the enable command. When the control parameter is in the enabled state, when the data clear command (or write command) is received from the host system 11, the memory controller 123 can execute the data clear command (or write command) according to the data clear command (or write command). The skip data clearing operation is performed.

In one embodiment, after the memory device 12 completes the skip data clearing operation, the host system 11 may send a disable command to the memory device 12 . In response to this disable command, the memory controller 123 may disable the skip data clear operation. For example, the memory controller 123 may set a control parameter corresponding to the skip data clearing operation to a disabled state according to the disable command. When the control parameter is in the disabled state, when a write command is received from the host system 11, the memory controller 123 can perform a normal data write operation according to the write command. In a normal data write operation, the memory controller 123 can write data to all the logical block addresses indicated by the write command according to the instruction of the write command. Taking FIG. 3 as an example, when a write command instructing to write data to logical block addresses N~N+8 is received, in a normal data write operation, the memory controller 123 can write data to the logical block. Addresses N~N+8 perform a complete sequential write instead of a skip data write as shown in FIG. 4 .

FIG. 5 is a flowchart of a skip data clearing method according to an embodiment of the present invention. Referring to FIG. 5, in step S501, a data clearing command is received from the host system, wherein the data clearing command is used to clear data belonging to the target logic range. In step S502, in response to the data clearing instruction, a skip data clearing operation is performed. The skip data clearing operation includes writing preset data to a plurality of discrete logical block addresses within the target logical range.

However, the steps in FIG. 5 have been described in detail as above, and will not be repeated here. It should be noted that each step in FIG. 5 can be implemented as a plurality of program codes or circuits, which is not limited by the present invention. In addition, the method of FIG. 5 can be used in conjunction with the above exemplary embodiments, and can also be used alone, which is not limited in the present invention.

To sum up, after receiving the data clearing command from the host system for clearing the data belonging to the target logical range, the memory device can automatically perform the skip data clearing operation. In particular, the skip data clearing operation includes writing preset data to a plurality of discrete logical block addresses within the target logical range. Thereby, the data clearing efficiency of the memory device can be effectively improved.

Although the present invention has been disclosed above by the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, The protection scope of the present invention shall be determined by the scope of the appended patent application.

10: Data storage system 11: Host system 12: Memory device 121: Connection interface 122: Memory module 123: Memory Controller 210: Storage area 220: idle area 201(1)~201(B): Entity unit 202(1)~202(C): Logic Unit S501, S502: steps

FIG. 1 is a schematic diagram of a data storage system according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a management memory module according to an embodiment of the present invention. FIG. 3 is a schematic diagram of logical block addresses to be cleared by a data clearing command according to an embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a skip data clearing operation according to an embodiment of the present invention. FIG. 5 is a flowchart of a skip data clearing method according to an embodiment of the present invention.

S501, S502: steps

Claims (9)

A skip-type data clearing method for a memory device, and the skip-type data clearing method comprises: receiving a data clearing command from a host system, wherein the data clearing instruction is used to clear data belonging to a target logic range; and in response to the data clearing instruction, executing a skip data clearing operation, wherein the skipping data clearing operation includes: writing a preset data to a plurality of discontinuous logical block addresses within the target logical range; Determine whether a specific logical block address within the target logical range has stored valid data; and if the specific logical block address does not store the valid data, do not write the default data to the specific logical block site. The skip data clearing method according to claim 1, wherein the data clearing command includes at least one writing command, and the at least one writing command instructs to write the default data to all logical areas within the target logical range block address. The skip data clearing method as claimed in claim 1, wherein the default data includes random data or meaningless data. The skip data clearing method as claimed in claim 1, wherein the step of writing the default data to the plurality of discontinuous logical block addresses within the target logical range comprises: writing the default data to a first logic block bit within the target logic range address and a second logical block address, wherein there are P logical block addresses between the first logical block address and the second logical block address, and the P logical block addresses are not Write the default data, and P is a positive integer. The skip data clearing method according to claim 1, wherein the step of judging whether the specific logical block address in the target logical range has stored the valid data comprises: judging a mapping information of the specific logical block address exists in a mapping table. The skip data clearing method as claimed in claim 1, further comprising: before receiving the data clear command from the host system, receiving an enabling command from the host system; and enabling the skipping in response to the enabling command Data clear operation. A data storage system includes: a host system; and a memory device coupled to the host system, wherein the host system is used to transmit a data clearing command to the memory device, the data clearing command is used to clear a data within the target logical range, and in response to the data clearing command, the memory device is configured to perform a skip data clearing operation, wherein the skip data clearing operation includes: writing a preset data to the target logical range multiple discontinuities within logical block address; determine whether a specific logical block address within the target logical range has stored valid data; and if the specific logical block address does not store the valid data, do not write the default data to The specific logical block address. The data storage system of claim 7, wherein the operation of writing the default data to the plurality of discontinuous logical block addresses within the target logical range comprises: writing the default data to the A first logical block address and a second logical block address within the target logical range, wherein there are P logical block bits between the first logical block address and the second logical block address address, the P logical block addresses are not written into the default data, and P is a positive integer. A skip-type data clearing method for a memory device, and the skip-type data clearing method comprises: receiving an enabling command from a host system; in response to the enabling instruction, enabling a skip-type data clearing operation; The host system receives a data clearing command, wherein the data clearing command is used to clear data belonging to a target logic range; and in response to the data clearing command, executes the skip data clearing operation, wherein the skipping data clearing operation includes: A predetermined data is written to a plurality of discontinuous logical block addresses within the target logical range.

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