CN101794257B - Data updating method and device for data storage type flash memory - Google Patents

Abstract

The invention relates to NAND Flash, and discloses a data updating method and device of a data storage type Flash memory and a storage device. The data updating method of the data storage type flash memory comprises the following steps: receiving update data; if the address to be written in the updating data is continuous with the storage address of the previous writing operation, writing the updating data next to the storage address; otherwise, judging whether the length of the updated data is larger than a preset value; if the length of the updated data is larger than the preset value, copying the lower half part and the upper half part of data in the block executed by the previous write operation to a new block into which the updated data needs to be written, and writing the updated data into the new block; and otherwise, writing the updated data into a cache block for temporarily storing data in the data storage type flash memory, wherein the cache block corresponds to at least one logic block, and the page included in the cache block corresponds to the page included in the logic block. The number of times of writing and erasing operations to the NAND Flash can be reduced.

Description

Data updating method and device for data storage type flash memory

technical field

The present invention relates to a data storage type flash memory (NAND Flash), in particular to a data updating method and device for a data storage type flash memory. the

Background technique

With the widespread application of mobile devices such as U disks, digital cameras, and mp3 music players, flash memory (FLASH) memory has gradually replaced other semiconductor storage components and has become the carrier of main data and programs in embedded systems. NAND FLASH is a non-volatile memory that can be erased multiple times online. Its structure provides extremely high cell density, which can achieve high-density storage of data, and the speed of writing and erasing is also very fast, so NAND FLASH is an ideal solution for high-density data storage. the

Similar to disks, the basic granularity of reading and writing data in NAND Flash is pages. In addition, Flash does not allow direct overwriting of data. Old data must be erased before new data can be written. The granularity of erasing is block, and a block usually contains 64 pages. The writing mechanism of NAND Flash is not like other FLASH devices. NAND Flash requires that when writing data, the data must be erased first. Therefore, when we write data, we first read the content of the data block to be written into the block buffer, and then write the data to be written into the NAND Flash into the block buffer (Block Buffer) in the form of pages. corresponding address. Then erase the block that previously stored the data, and finally write the updated data to the NAND Flash. After this series of operations, the logical writing of NAND Flash data is realized. NAND Flash also has an operation called copyback. When the data of a certain page needs to be copied to a new location, it only needs to be read into the block cache, and then write the data of the page according to the received target address. Enter the new location on the NAND Flash. In general, the write address of NAND data is not continuous (usually, the data structure of NAND Flash includes file allocation table (FAT, File Allocation Table), file directory table (FDT, File Directory Table) and data (DATA) area , three data structures respectively store FAT, FDT and DATA data, Figure 1 shows the specific flow of the existing NAND Flash write operation:

Step S10, copy (copy) the upper part of the data of the old block BOLCKA to the new block BLOCKA';

Step S11, write the update data received from outside to the old block BLOCKA into the new block BLOCKA';

Step S12, saving the current storage location;

Step S13, if the storage address of the data received next time is continuous with the current storage address, then store at the storage location; if the data address is not continuous, copy the lower part of the data of the old block BOLCKA to the new block BLOCKA'; then repeat the steps S10-S13. the

It can be seen from the above process that in the prior art, since the write address of the NAND Flash receiving data changes at any time, each time the data is received from the USB interface and the NAND Flash needs to be updated, the write operation needs to go through the process from the old block to the new block first. After the copy operation of the block, the updated data can be written to the new block, which increases the number of write and erase operations on NAND Flash and reduces the service life of NAND Flash. the

Contents of the invention

The purpose of the present invention is to provide a data update method and device and storage device for data storage type flash memory, which can reduce the number of operations for writing and erasing NAND Flash. the

The present invention provides a method for updating data of a data storage type flash memory, comprising steps:

receive update data;

Judging whether the address to be written to the update data is continuous with the storage address of the previous write operation;

If the address to be written to the update data is continuous with the storage address of the previous write operation, write the update data immediately after the storage address;

If the address to be written to the update data is discontinuous with the storage address of the previous write operation, determine whether the length of the update data is greater than a preset value; if the length of the update data is greater than the preset value, write the previous Copy the lower half and upper half of the data in the block executed by one write operation to the new block where the update data needs to be written, and write the update data into the new block; if the length of the update data is less than Or equal to the preset value, write the update data into a cache block for temporarily storing data in the data storage type flash memory, the cache block corresponds to at least one logical block, and the pages included in the cache block correspond to the corresponding to the pages included in the logical block. the

Preferably, writing the update data into a cache block for temporarily storing data in the data storage type flash memory specifically includes the steps of:

Allocate a cache block for the new block to be written to the update data;

Writing the updated data into the cache block. the

Preferably, before allocating the cache block for the new block to be written to the update data further includes:

Determine whether there is a cache block corresponding to the new block;

If there is no cache block corresponding to the new block, perform the step of allocating a cache block for the new block to be written to the update data;

If there is a cache block corresponding to the new block, write the update data into the cache block corresponding to the new block. the

Preferably, if there is a cache block corresponding to the new block, writing the update data to the cache block corresponding to the new block further includes:

Judging whether the cache block corresponding to the new block has enough space;

If there is enough space, perform the step of writing the update data into the cache block corresponding to the new block;

If there is not enough space, select a cache block to reclaim, allocate a new cache block for the new block after recycling, and write the updated data into the new cache block. the

Preferably, the allocation of cache blocks for the new blocks to be written to the update data specifically includes the steps:

Determine whether there are unused cache blocks;

If there is an unused cache block, write the update data into the unused cache block;

If there is no unused cache block, select a cache block to reclaim, allocate a new cache block for the new block after recycling, and write the updated data into the new cache block. the

Preferably, the selection of a cache block to reclaim specifically includes the steps:

Determine whether there are cache blocks that have not been used for a long time;

If there is a cache block that has not been used for a long time, reclaim the cache block that has not been used for a long time. the

Preferably, if there is no cache block that has not been used for a long time, the method also includes:

Obtain the usage of each cache block;

A cache block is selected and reclaimed according to the usage of each cache block. the

Preferably, the usage of the cache block includes:

The number of used pages of the cache block, the corresponding relationship, and the number of corresponding blocks. the

The present invention provides a data update device for data storage flash memory, including:

A receiving unit for receiving update data;

A judging unit, configured to judge whether the address to be written to the update data received by the receiving unit is continuous with the storage address of the previous write operation; if the address to be written to the update data is not continuous to the storage address of the previous write operation , judging whether the length of the update data is greater than a preset value;

A write unit, configured to write the update data next to the storage address when the judgment unit judges that the address to be written into the update data is continuous with the storage address of the previous write operation; when the judgment unit judges that the update data When the length is greater than the preset value, the lower half and upper half of the data in the block executed by the previous write operation are copied to the new block where the update data needs to be written, and the update data is written into the new block. Described new block; Judging in the judgment unit that the length of the update data is less than or equal to the preset value, the update data is written into the cache block used for temporarily storing data in the data storage type flash memory, and the cache block Corresponding to at least one logical block, the pages included in the cache block correspond to the pages included in the logical block. the

Preferably, the writing unit includes:

An allocation unit, configured to allocate a cache block for the new block to be written to the update data;

A write operation unit, configured to write the update data into the cache block allocated by the allocation unit. the

Preferably, the distribution unit includes:

A cache block recycling unit, used to select a cache block to reclaim when there is no unused cache block and the cache block corresponding to the new block to be written to the update data does not have enough space;

The cache block allocating unit is configured to allocate a new cache block for the new block after the cache block reclaiming unit selects a cache block to reclaim. the

The present invention provides a storage device, including a data storage flash memory and a data updating device for the data storage flash memory provided by the present invention. the

The finishing method, device and browser of the browser historical records of the present invention, when the update data is less than the preset value, the update data can be written into the Cache block used for temporarily storing data in the NAND Flash, thereby when the update data is less than the preset value When setting a value, it can reduce the number of times of writing and erasing operations on NAND Flash, and improve the service life of NAND Flash. the

Description of drawings

Fig. 1 is the schematic flow chart of the data updating method of NAND Flash in the prior art;

Fig. 2 is the schematic flow sheet of the data updating method of NAND Flash of the present invention;

Fig. 3 is a schematic diagram of the relationship between a Cache block and a Logic block of the present invention;

Fig. 4 is the structural representation of the data updating device embodiment one of NAND Flash of the present invention;

Fig. 5 is the structural representation of the data updating device embodiment two of NAND Flash of the present invention;

Fig. 6 is a schematic structural diagram of Embodiment 3 of a data updating device for NAND Flash of the present invention. the

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings. the

Detailed ways

The invention provides a data updating method, device and storage device of NAND Flash, which can reduce the number of times of writing and erasing operations on NAND Flash, thereby improving the service life of NAND Flash. the

First introduce the data updating method of NAND Flash that the present invention provides, Fig. 2 has described the flow process of the data updating method embodiment one of NAND Flash, comprise:

Step s21, receiving update data;

Update data can be received through the Universal Serial Bus (USB: Universal Serial Bus) interface or other interfaces;

Step s22, judging whether the address to be written to update data is continuous with the storage address of the previous write operation; if the address to be written to update data is continuous to the storage address of the previous write operation, enter step s23; if the update data needs to be written The input address is not continuous with the storage address of the previous write operation, enter step s24;

Step s23, writing update data immediately after the storage address;

Immediately after the storage address writes the update data, save the storage address after the update data is written, and wait for the next update data;

Step s24, judging whether the length of the updated data is greater than the preset value; if the length of the updated data is greater than the preset value, proceed to s25; if the length of the updated data is less than or equal to the preset value, proceed to s26;

The preset value can be set according to different nand flash specifications, for example, it can be set to 0x10. the

Step s25, copy the lower half and upper half of the data in the block executed by the previous write operation to the new block where the updated data needs to be written, and write the updated data into the new block;

Step s26, write the update data into the cache (Cache) block for temporarily storing data in the NAND Flash. the

In an embodiment of the present invention, step s26 may specifically include: allocating a Cache block for the new block to be written into the update data; and writing the update data into the Cache block. the

After writing the updated data into the Cache block, restore the storage address of the saved location, and wait for the next updated data;

Wherein, before allocating the Cache block for the new block that needs to be written into the update data, it can further include: judging whether there is a Cache block corresponding to the new block; if there is no Cache block corresponding to the new block, then executing The steps of allocating Cache blocks for new blocks; if there is a Cache block corresponding to the new block, and the Cache block corresponding to the new block has enough space, then the updated data is written into the Cache block corresponding to the new block, otherwise a Cache block needs to be selected The block is recycled, and a new Cache block is allocated for the new block after recycling, and then the updated data is written into the new Cache block. the

Wherein, assigning the Cache block for the new block that needs to be written into the update data specifically includes the steps of: judging whether there is an unused Cache block; if there is an unused Cache block, writing the update data into the unused Cache block; For the used Cache block, select a Cache block for recycling, allocate a new Cache block for the new block after recycling, and write the updated data into the new Cache block. the

As can be seen from the above, in this embodiment, when the update data is less than the preset value, the update data can be written into the Cache block for temporarily storing data in the NAND Flash, so that when the update data is less than the preset value, the NAND Flash can be reduced. The number of write and erase operations improves the service life of NAND Flash. the

Wherein, in the embodiment of the present invention, the Cache block corresponds to at least one logical block, and the pages included in the Cache block correspond to the pages included in the logical block. The corresponding relationship between a cache block and a logic (Logic) block provided by the present invention is shown in the figure 3 shows:

Cache block corresponds to Logic block A and Logic block B, Logic block A includes A block page 1 and A block page 30, Logic block B includes B block page 1, B block page 2 and B block page 3; Logic block A and Logic The pages included in block B correspond to the pages included in the Cache block. Originally written data should be written in Logic Block A and Logic Block B, but after the introduction of Cache block management, the written small data is actually written into the Cache block, and the originally written data should be written in the LogicB block, but actually written in the Cache block. the

In order to manage the Cache, it is necessary to limit the maximum number of Logic blocks that can be recorded in a Cache block. When the corresponding relationship between the Cache block and the Logic block is not enough, the Logic block A needs to be reclaimed. The recycling process is as follows. Logic block A and the content belonging to Logic block A in the Cache block are merged into a new Logic block A1. After recycling, the corresponding relationship between the Cache block and the pages in Logic block A is invalid, so it is not necessary to manage the Cache The part of the block corresponding to Logic block A, because logically the page of Logic block A has been reclaimed into Logic block A1, that is, the cache block is not physically reclaimed, resulting in logical recycle but not physical recycle, and the unused pages in the Cache block Pages can then be allocated to other Logic blocks for continued use; only when all the pages of an entire Cache block are used up, all corresponding Logic blocks in the Cache block need to be reclaimed before physically erasing and reclaiming the Cache blocks. pages included. Thereby reducing the number of operations that Logic blocks need to recycle. the

In the embodiment of the present invention, the following criteria can be used to select a cache block for recycling: preferentially select a cache block that has not been used for a long time, and how long it can be recycled can be set as required. When there is no cache block that has not been used for a long time, after obtaining the usage of each cache block, select a cache block according to the usage of each cache block and recycle it. Specifically, the number of pages used and the corresponding relationship of each cache block can be obtained , the corresponding block number and other information. the

Introduce the data updating device of the NAND Flash that the embodiment of the present invention provides again, Fig. 4 has described the structure of the data updating device embodiment one of NAND Flash, comprise:

A receiving unit 401, configured to receive update data;

The judging unit 402 is used to judge whether the address to be written in the update data received by the receiving unit 401 is continuous with the storage address of the previous write operation; if the address to be written in the update data is not continuous with the storage address of the previous write operation, judge Whether the length of the update data is greater than the preset value;

The writing unit 403 is used to write the update data next to the storage address when the judging unit 402 judges that the address to be written in the update data is continuous with the storage address of the previous write operation; when the judgment unit 402 judges that the length of the update data is greater than the preset value, copy the lower half and upper half data in the block performed by the previous write operation to the new block where the update data needs to be written, and write the update data into the new block; judge the length of the update data at the judging unit 402 When being less than or equal to the preset value, the update data is written into the Cache block for temporarily storing data in NANDFlash, the Cache block corresponds to at least one logic block, and the pages included in the Cache block correspond to the pages included in the logic block. the

As can be seen from the above, in this embodiment, when the update data is less than the preset value, the update data can be written into the Cache block for temporarily storing data in the NAND Flash, so that when the update data is less than the preset value, the NAND Flash can be reduced. The number of write and erase operations increases the service life of NAND Flash. the

Fig. 5 has described the structure of the second embodiment of the data updating device of the present invention, and the difference from the first embodiment of the data updating device is that the writing unit 403 includes: an allocation unit 4031, which is used to allocate a Cache block for a new block to be written to update data ; The write operation unit 4032 is used to write the update data into the Cache block allocated by the allocation unit 4031 . the

Fig. 6 has described the structure of the third embodiment of the data updating device of the present invention, and the difference from the second embodiment of the data updating device is that the allocation unit 4031 includes: a Cache block reclaiming unit 40311, which is used for updating when there are no unused Cache blocks and When the Cache block corresponding to the new block that data needs to be written does not have enough space, select a Cache block to reclaim; the Cache block allocation unit 40312 is used to allocate a new block after the Cache block recovery unit 40311 selects a Cache block to reclaim New cache block. the

The present invention also provides a storage device, which includes a NAND Flash and a data update device for the NAND Flash provided by the present invention. the

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related All technical fields are equally included in the scope of patent protection of the present invention. the

Claims (10)

1. A data update method for data storage type flash memory, characterized in that, comprising the steps: receive updated data; Judging whether the address to be written to the update data is continuous with the storage address of the previous write operation; If the address to be written to the update data is continuous with the storage address of the previous write operation, write the update data immediately after the storage address; If the address to be written to the update data is discontinuous with the storage address of the previous write operation, determine whether the length of the update data is greater than a preset value; if the length of the update data is greater than the preset value, write the previous Copy the lower half and upper half of the data in the block executed by one write operation to the new block where the update data needs to be written, and write the update data into the new block; if the length of the update data is less than Or equal to the preset value, write the update data into a cache block for temporarily storing data in the data storage type flash memory, the cache block corresponds to at least one logical block, and the pages included in the cache block correspond to the corresponding to the pages included in the logical block. 2. The data updating method of the data storage type flash memory as claimed in claim 1, wherein said writing said update data into the cache block for temporarily storing data in the data storage type flash memory specifically comprises the steps of: Allocating a cache block for the new block to be written to the update data; Writing the updated data into the cache block. 3. The data update method of data storage type flash memory as claimed in claim 2, characterized in that, before allocating a cache block for the new block to be written into the update data, further comprising: judging whether there is a cache block corresponding to the new block; If there is no cache block corresponding to the new block, perform the step of allocating a cache block for the new block to be written to the update data; If there is a cache block corresponding to the new block, write the update data into the cache block corresponding to the new block. 4. The data updating method of the data storage type flash memory as claimed in claim 3, wherein if there is a cache block corresponding to the new block, writing the update data into the cache block corresponding to the new block Before the cache block further includes: judging whether the cache block corresponding to the new block has enough space; If there is enough space, perform the step of writing the update data into the cache block corresponding to the new block; If there is not enough space, select a cache block to reclaim, allocate a new cache block for the new block after recycling, and write the updated data into the new cache block. 5. The data updating method of the data storage type flash memory as claimed in claim 2, wherein said allocating a cache block for a new block to be written into said update data specifically comprises the steps of: Determine whether there are unused cache blocks; If there is an unused cache block, writing the update data into the unused cache block; If there is no unused cache block, select a cache block to reclaim, allocate a new cache block for the new block after recycling, and write the updated data into the new cache block. 6. The data updating method of data storage type flash memory as claimed in claim 4 or 5, wherein said selecting a cache block to reclaim specifically comprises the steps of: Determine whether there are cache blocks that have not been used for a long time; If there is a cache block that has not been used for a long time, reclaim the cache block that has not been used for a long time. 7. The data updating method of data storage type flash memory as claimed in claim 6, is characterized in that, if there is no cache block that has not been used for a long time, the method also includes: Obtain the usage of each cache block; A cache block is selected and reclaimed according to the usage of each cache block. 8. The data updating method of the data storage type flash memory as claimed in claim 7, wherein the usage of the cache block includes: The number of used pages of the cache block, the corresponding relationship, and the number of corresponding blocks. 9. A data update device for data storage flash memory, characterized in that it comprises: a receiving unit, configured to receive update data; A judging unit, configured to judge whether the address to be written to the update data received by the receiving unit is continuous with the storage address of the previous write operation; if the address to be written to the update data is not continuous to the storage address of the previous write operation , judging whether the length of the update data is greater than a preset value; A write unit, configured to write the update data next to the storage address when the judgment unit judges that the address to be written into the update data is continuous with the storage address of the previous write operation; when the judgment unit judges that the update data When the length is greater than the preset value, the lower half and upper half of the data in the block executed by the previous write operation are copied to the new block where the update data needs to be written, and the update data is written into the new block. Described new block; Judging in the judgment unit that the length of the update data is less than or equal to the preset value, the update data is written into the cache block used for temporarily storing data in the data storage type flash memory, and the cache block Corresponding to at least one logical block, the pages included in the cache block correspond to the pages included in the logical block. 10. The data updating device of the data storage type flash memory as claimed in claim 9, wherein the writing unit comprises: An allocation unit, configured to allocate a cache block for a new block to be written into the update data; A write operation unit, configured to write the update data into the cache block allocated by the allocation unit.

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