KR100950281B1 - Flash memory system and data calculation method of flash memory - Google Patents

Abstract

The present invention relates to a flash memory system and a data operation method of a flash memory. The flash memory system according to the present invention includes a plurality of blocks, and includes block state information and operation information for each of the plurality of blocks. A stored flash memory; An internal buffer having a predetermined storage capacity and temporarily storing data for data operation on the flash memory; The data desired for the operation is first stored in the internal buffer, and according to the block state information of the flash memory and the data storage state of the internal buffer, the data operation of the data stored in the internal buffer into the corresponding block of the flash memory. An operation control unit for controlling performance is provided. According to the present invention, efficient mapping and data operations in large block flash memories are possible.

Flash, Large Block, Small Block, Flash Conversion Layer, Inner Block, M Block, N Block

Description

Flash memory system and method for data operation of flash memory}

The present invention relates to a flash memory system and a flash memory data operation method, and more particularly, to a flash memory system and a flash memory data operation method for efficiently performing data operation in a large block flash memory.

Flash memory has the advantages of Random Access Memory (RAM), which is free to write and delete data, and Read Only Memory (ROM), which preserves stored data without powering up. In addition, since the power consumption is lower than that of a storage medium based on magnetic disk memory, and the size is fast and has the same access time as a hard disk, the system is embedded in portable electronic devices such as digital cameras, PDAs, and MP3 players. It is widely used in applications such as System) and Mobile System.

Flash memory has a nonvolatile characteristic of permanently storing data even after power supply is interrupted due to hardware characteristics. In addition, unlike a hard disk, it is impossible to overwrite a sector in which data is already present. Due to this property, an operation before erasing the entire block including the corresponding sector is required before writing data. In addition, the unit of data to be deleted is larger than that of write data.

This feature not only makes it difficult to use the flash memory as a main memory but also prevents the use of a file system for a general hard disk even when the flash memory is used as an auxiliary storage device.

Therefore, a flash memory based system uses a Flash Translation Layer (FTL) between the file system and the flash memory to overcome the inherent hardware limitations of the flash memory.

1 shows a block diagram of a typical flash memory system.

As shown in FIG. 1, a general flash memory system includes an application program 12 at a top level, a file system 12 having a user program mounted thereon, and a predetermined data operation according to a user's request. That is, it includes a flash translation layer 16 that transfers read and write operations of the flash memory 18 to the flash memory 18.

The file system 14 continuously executes a read or write operation request for a logical sector address in order to read data stored in the flash memory 18 or store data in the flash memory 18, and converts the flash By the algorithm of layer 16 this logical sector address is changed to the physical sector address of the actual flash memory 18.

The flash translation layer 16 maps the logical address generated by the file system to the physical address of the flash memory 18 in which the erase operation is performed during the data operation operation of the flash memory 18.

Due to the address mapping function of the flash translation layer 16, the host recognizes the flash memory 30 as a hard disk driver and can access the flash memory device in the same manner as the hard disk driver.

The flash memory 18 may generally be divided into a small block flash memory and a large block flash memory.

The small block flash memory has the same physical operation unit as the logical operation unit, whereas the large block flash memory has a larger physical operation unit than the logical operation unit. In general, logical units of computation are commonly referred to as sectors as host-side computational units, and physical units of computation are often referred to as pages as actual units in flash memory. For example, the large block flash memory has a data sector size of 512B in most operating systems, whereas the basic unit of data physical operation when reading or writing data is 2 KB or 1 KB.

2 shows the structure of a small block flash memory and a large block flash memory. 2 (a) shows an example of the structure of a large block flash memory, and FIG. 2 (b) shows an example of the structure of a small block flash memory.

As shown in FIG. 2A, the large block flash memory is composed of 1024 blocks Block0 to Block1023 in the case of 128MB flash memory, and one block is composed of 64 pages (Page0 to Page63). The page has a structure composed of four sectors. Here, one page may have a main array area (sector area) of 2 KB and a spare area (spare area) of 64B.

As shown in FIG. 2B, in the case of a 128 MB small block flash memory, 8192 blocks Block0 to Block8191 are configured, and one block is composed of 32 pages Page0 to Page31. One page also has 512B, which is the size of the sector that the filesystem sees. Even in this case, one page may have a main array area (sector area) of 512B and a spare area (spare area) of 16B.

3 is a diagram for describing an example of a data operation and mapping method in a general small block flash memory system.

FIG. 3 (a) shows a sequence for a write operation request for a logical sector address from a file system, FIG. 3 (b) shows a mapping table, and FIG. 3 (c) shows the structure of a small block flash memory. will be. For convenience of explanation and explanation, it is assumed that the small block flash memory is composed of three pages. As described above, in the case of the small block flash memory, since the page is the same as the sector and the size, the sector and the page can be used as a similar meaning.

As shown in FIG. 3, a file system first requests a continuous write operation for a specific logical sector. For example, write (3, D ₃ ) in Fig. 3A means that data D ₃ is written to logical sector number 3. Here, the logical sector number is a number in which the flash memory is numbered in sequence in the file system, assuming that there are logically n sectors (a value determined according to the capacity of the flash memory). Since it is assumed that one block is composed of three pages, inferring from logical sector number 3 will result in logical block number lbn 1 and an offset of 0.

According to the mapping table of FIG. 3B, the logical block number lbn 1 is mapped to the physical block number pbn 10. Since the offset is 0, the data D ₃ is written at the position of offset 0 of the physical block number pbn 10 of FIG. 3C. According to this principle, a data write operation on data D ₄ , D ₅ , D ₆ , and D ₇ corresponding to logical sector numbers ₄ , ₅ , ₆ , and ₇ is performed. Accordingly, data D ₄ is located at position 1 of offset 1 of physical block number pbn of the flash memory, data D ₅ is positioned at position 2 of offset 2, data D ₆ is positioned at offset 0 of position 11 of physical block number pbn. At position 1, data D ₇ is used.

In the last write (7, D ₇ ) operation, logical sector number 7 is logical block number 2 (7/3 quotient) and offset is 1 (7% 3), and data is already written at the position. In this case, since the erase operation must be performed for the operation of updating data at the same location, the data D ₇ cannot be written at the position of offset 1 of the physical block number pbn 11. At this time, it writes to another empty position (for example, the position of offset 2 of physical block number pbn) and stores logical sector number 7 as spare information in the spare area. The operation information stored in the spare area is used to find out which data is the latest data for logical sector number 7 in a read operation or the like.

On the other hand, in recent years, large block flash memory has been released rather than small block flash memory due to the trend of increasing the capacity of the flash memory. As described above, in the case of the large block flash memory, the physical operation unit is larger than the logical operation unit.

In a large block flash memory having such a structure, it is difficult to use a mapping method or a data operation method that is generally applied to a small block flash memory. Therefore, there is a need for a data operation method including a flash memory system and a mapping method that can be efficiently applied to a large block flash memory.

Accordingly, an object of the present invention is to provide a flash memory system and a data operation method capable of overcoming the aforementioned problems.

Another object of the present invention is to provide a flash memory system and a data operation method which can be efficiently applied to a large block flash memory.

Another object of the present invention is to provide a flash memory system and a data operation method for efficient mapping of a large block flash memory.

Another object of the present invention is to provide a flash memory system and a data operation method for performing data operation of a large block flash memory using an internal buffer.

According to an embodiment of the present invention for achieving some of the technical problems described above, a flash memory system according to the present invention includes a plurality of blocks, and has block state information and operation information for each of the plurality of blocks therein. A stored flash memory; An internal buffer having a predetermined storage capacity and temporarily storing data for data operation on the flash memory; The data desired for the operation is first stored in the internal buffer, and according to the block state information of the flash memory and the data storage state of the internal buffer, the data operation of the data stored in the internal buffer into the corresponding block of the flash memory. An operation control unit for controlling performance is provided.

The flash memory may be a large block flash memory having a storage capacity larger than that of a logical operation unit.

The flash memory may include a plurality of blocks, each of the plurality of blocks including a plurality of pages, and each of the plurality of pages may have a plurality of sectors.

The data operation may be a data write operation.

The internal buffer may have a storage capacity corresponding to n times (n is a natural number) of the storage capacity of the physical operation unit of the flash memory.

The operation control unit preferentially stores calculation target data in the internal buffer, and at least data of a storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory is stored in the internal buffer; or When the operation target physical page is changed, a data operation may be performed on a block of the flash memory of data stored in the internal buffer.

The blocks of the flash memory may include at least one of a first type block (M block) in which page offsets and a sector offset coincide, or a second type block including data in which page offsets and sector offsets do not coincide. The block state information on the first type block and the second type block may include information on the first type block and information on the second type block.

The operation control unit preferentially stores the input calculation target data in the internal buffer, and stores at least as much data as the storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory in the internal buffer. According to whether or not and the logical sector offset corresponding to the operation target data is sequentially input, data stored in the internal buffer or input operation data can be performed on the corresponding block of the flash memory.

The operation controller may be configured to continuously maintain the second type block state or the second type block state when the block of the flash memory is expected to maintain the first type block state or the first type block state. In the case where it is expected to maintain the data, the internal buffer stores at least as much data as the storage capacity corresponding to n times the physical operation unit of the flash memory (n is a natural number) or when the physical page offset value changes. Perform a data operation on the corresponding block of the flash memory of data stored in the internal buffer or input association data, wherein the block of the flash memory is changed from the first type block state to the second type block state; In the case of inputting the calculation target data that is expected to change, at the time of inputting the calculation target data A data operation of the input association data or data stored in the internal buffer may be performed on a corresponding block of the flash memory.

The logical operation unit of the flash memory may be a sector, and the physical operation unit may be a page.

The block state information of the flash memory may be stored in a meta block that stores information about the flash memory, or may be stored in each block.

According to another embodiment of the present invention for achieving some of the above technical problem, the data operation method of the flash memory according to the present invention, preferentially stores the target data to be calculated in an internal buffer having a predetermined storage capacity Data stored in the internal buffer or stored in the internal buffer according to whether or not data corresponding to a storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory is stored or the physical page offset value is changed. And determining whether to perform a data operation on the flash memory.

The flash memory may be a large block flash memory having a larger capacity of a physical operation unit than a logical operation unit.

The internal buffer may have a storage capacity corresponding to n times (n is a natural number) of the storage capacity of the physical operation unit of the flash memory.

According to still another embodiment of the present invention for achieving some of the above technical problems, a data operation method of a flash memory according to the present invention includes the steps of inputting a logical sector number and the calculation target data; Storing the operation target data in a predetermined order in an internal buffer having a storage capacity corresponding to n times (n is a natural number) of the storage capacity of the physical operation unit of the flash memory; The blocks of the flash memory may be divided into a first type block in which all stored data coincide with a page offset and a sector offset, or a second type block including at least one of data stored in which the page offset and sector offset do not match. Perform data operation on the flash memory of data stored in the internal buffer or input target data, and maintain the first type block state when input of logical sector offsets calculated through the logical sector number is sequential; Performing an operation and performing a data operation to transition to the second type block state if the input of the logical sector offsets is not sequential.

The flash memory may be a large block flash memory having a larger capacity of a physical operation unit than a logical operation unit.

The data operation to the flash memory is stored in the internal buffer at least as much as the storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory or when the physical page offset value is changed. It can be performed in units of physical operations.

The logical operation unit of the flash memory may be a sector, and the physical operation unit may be a page.

The data operation may be a data write operation.

According to another embodiment of the present invention for achieving some of the above technical problems, the data read operation method of the flash memory according to the present invention, all stored data is the first type block or page offset and sector offset match or stored Identifying block state information of an operation target block of the flash memory in which the block state is divided into a second type block including at least one of data whose page offset and sector offset do not coincide; If the block of the flash memory is the first type block, the data of page offset and sector offset are read and operated. If the block of the second type block is the second type block, the operation information stored in the spare area of the block of the flash memory is reversed. Scanning to perform a read operation on the most recently stored data.

According to another embodiment of the present invention for achieving some of the above technical problems, a mapping control method of a flash memory according to the present invention includes the steps of inputting a logical sector number for data operation; When the logical sector number is lsn, the logical block number is lbn, the logical page offset is lpo, the logical sector offset is lso, the number of pages per unit block is np, and the number of sectors per unit page is ns. obtaining the logical block number, the logical page offset, and the logical sector offset value by / (np * ns), tmp = lsn% (np * ns), lpo = tmp / ns, and lso = tmp% ns; ; Retrieving a physical block corresponding to the logical block number according to a predefined mapping table; In principle, data mapping is performed at a position of a physical page offset and a physical sector offset coinciding with the logical page offset and the logical sector offset, but the physical page offset and the physical page offset coincide with the logical page offset and the logical sector offset. If data is already stored at the position of the sector offset, performing the mapping for the data operation to the adjacent position or any position.

The flash memory has a plurality of blocks, each of the plurality of blocks includes a plurality of pages, each of the plurality of pages has a structure having a plurality of sectors, and is physically larger than the sector, which is a logical operation unit. It may be a large block flash memory having a larger capacity of the page, which is an operation unit.

According to the present invention, efficient mapping and data operations in large block flash memories are possible. That is, data write and read operations optimized for large block flash memory can be performed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings without any intention other than to provide a thorough understanding of the present invention to those skilled in the art.

Prior to the detailed description of the present invention, unlike a small block flash memory, in the case of a large block flash memory, a logical block number lbn, a logical page offset lpo, and The logical sector offset (lso) value should be available.

Given the logical sector number lsn, the logical block number lbn, logical page offset lpo, and logical sector offset lso are calculated by the following equations.

(1) lbn = lsn / (np * ns),

(2) tmp = lsn% (np * ns),

(3) lpo = tmp / ns,

(4) lso = tmp% ns

Where 'np' is the number of pages per block and 'ns' is the number of sectors per page. The logical block number (lbn) and the logical page offset (lpo) are determined by taking the quotient of division (/) in the expressions (1) and (2), and '%' is the target value for the remainder of the division. Operator.

If a 128 MB large block flash memory is composed of 1024 blocks, each block has 64 pages, and each page has 4 sectors, the above equation applies to the logic when the input logical sector number is 101. The block number lbn will be 0, the logical page offset lpo will be 25, and the logical sector offset lso will be 1.

Hereinafter, unless a separate division is necessary, the small block flash memory and the large block flash memory are described separately or unless specifically referred to as the small block flash memory, generally, the flash memory should be recognized as meaning the large block flash memory. something to do,

4 is a diagram illustrating an example of a data operation and mapping method of a large block flash memory according to an exemplary embodiment of the present invention. FIG. 4 assumes a case where the large block flash memory is applied to the flash memory system of FIG. 1.

FIG. 4 (a) shows a sequence for a write operation request for a logical sector address from a file system, FIG. 4 (b) shows a mapping table, and FIG. 4 (c) shows a block structure of a large block flash memory. It is shown. For convenience of explanation and explanation, it is assumed that the large block flash memory has three pages and one page is composed of four sectors. Accordingly, the physical block can be represented by a matrix structure having three rows of pages and four columns of sectors.

 In FIG. 4C, the first row of the three rows of the sector area has a physical page offset lpo = 0, the second row has a physical page offset lpo = 1, and the third row has a physical page offset ( lpo) = 2, wherein the first column of the four columns of the sector area is the physical sector offset lso = 0, the second column is the physical sector offset lso = 1, and the third column is the physical sector The offset lso = 2 and the fourth column may indicate the physical sector offset lso = 1.

First, in FIG. 4 (a), for the first write operation request 'write (4, D ₄ )', logical block number (lbn) = 0, logic by input logic sector number 4 and equations (1)-(4) The page offset lpo = 1 and the logical sector offset lso = 0 are calculated.

In the mapping table of FIG. 4B, the logical block number lbn = 0 is mapped to the physical block number pbn = 5, so the physical page offset of the physical block number pbn = 5 of the flash memory of FIG. Data D ₄ is written at positions (ppo) = 1 and physical sector offset (pso) = 0.

According to this principle, data write operations are performed on data D ₅ , D ₆ , D ₇ , D ₈ , and D ₉ corresponding to logical sector numbers ₅ , ₆ , ₇ , ₈ , and ₉ . Accordingly, data D ₅ , physical page offset lpo 1, and physical sector offset lso are located at positions of physical page offset lpo 1 and physical sector offset lso 1 of physical block number pbn 5 of the flash memory. at the 2-position, the data D _6, the physical page offset (lpo) 1 and physical position 3 sector offset (lso), the data D ₇ becomes spent, the physical block number (pbn) physical page offset (lpo) of 52, and Data D ₈ is written at the physical sector offset lso 0 and data D ₉ is written at the physical page offset lpo 2 and the physical sector offset lso 1.

In the case of the second write operation request write (8, D ₈ ) among the write operation requests having the same logical sector number (8, 9) in FIG. 4 (a), the logical block number (lbn) = 0 and the logical page offset (lpo). ) = 2, logical sector offset (lso) = 0, and physical block number (pbn) = 5, physical page offset (ppo) = 2, physical sector offset (pso) = 0 position (logical and physical Where the offset matches. However, since data has already been written to this position, data D ₈ is written and operated at the positions of physical block number (pbn) = 5, physical page offset (ppo) = 2, and physical sector offset (pso) = 2, and the operation information for this is As a result, the logical sector number lsn = 8 is stored in the corresponding spare area. The operation information stored in the redundant area is used to find out which data is the latest data for logical sector number 8 in a read operation or the like later.

In the case of the second write operation request write (9, D ₉ ), the physical block number pbn = 5, the physical page offset ppo = 2, and the physical sector offset pso = 3 according to the above-described principle. The data D ₉ is written and operated, and the logical sector number lsn = 9 is stored in the corresponding spare area as operation information thereof.

The principle as described above can be applied for data operations of a large block flash memory with more pages per block and more sectors per page. However, it is not an algorithm that takes advantage of the characteristics of large block flash memory. This is because eight flash memory write operations are required by eight write operation requests, as described with reference to FIG. 4. Since large block flash memory can perform write operations in units of pages, when four sectors per page are possible, one write operation can be performed for four sectors. Thus, in the example of FIG. 4, data can be stored in two write operations. Because there is. This may be possible through a flash memory system implemented through another embodiment of the present invention described below.

5 is a schematic block diagram of a flash memory system according to another exemplary embodiment of the present invention.

As shown in FIG. 5, the flash memory system 100 according to another embodiment of the present invention includes an operation controller 120, an internal buffer 130, and a flash memory 140.

The flash memory 140 has a large block flash memory structure as described above. That is, the physical operation unit (page) has a larger feature than the logical operation unit (sector). Here, the logical operation unit and the physical operation unit are not limited to sectors and pages but may have various sizes according to the device in which the flash memory is used.

The block state of the flash memory 140 may be divided into a first type block (M block) state and a second type block (N block) state. This will be described later.

The internal buffer 130 has a predetermined storage capacity, and is provided to temporarily store data for data operation on the flash memory 140. The internal buffer 130 is provided to perform an operation in a physical operation unit. That is, an internal buffer is provided to collect write operations for sectors and to perform write operations at once. For example, in the example of FIG. 4, it may be provided to allow data to be stored in two or less write operations.

The storage capacity of the internal buffer 130 may have a size of n times (n is a natural number) of the logical operation unit of the flash memory 140. For example, as shown in FIG. 4, when a page, which is a physical operation unit of a flash memory, has four sectors and one sector has a size of 512B, the internal buffer 130 is n times larger than 2KB. It can have

The operation control unit 120 preferentially stores data desired for operation in the internal buffer, and according to the block state information of the flash memory 140 and the data storage state of the internal buffer 130, the internal buffer ( The data operation for the corresponding block of the flash memory of the data stored in 130 is determined and controlled.

The operation controller 120 may be a concept including a file system and a flash conversion layer of the flash memory system described with reference to FIG. 1. At this time, the algorithm of the flash conversion layer will be different.

As described above, the file system continuously executes a read or write operation request for a logical sector address in order to read data stored in the flash memory or store data in the flash memory, and to the algorithm of the flash translation layer. This logical sector address is changed to the physical sector address of the actual flash memory.

In addition, the flash translation layer performs a function of mapping a logical address generated by a file system to a physical address of the flash memory 140 in which an erase operation is performed during a data operation operation on the flash memory 140. The flash conversion layer may be implemented in the form of hardware independent from the host system, or may be implemented in the form of a device driver inside the host system.

The operation controller 120 performs a data operation based on the block state information of the flash memory 140 and the storage state of the internal buffer 130.

In this case, when only the data storage state of the internal buffer 130 is used as a reference, the operation control unit 120 allows the calculation target data to be preferentially stored in the internal buffer 130. When at least as much data as the storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory 140 is stored in the internal buffer 130, the data stored in the internal buffer 130 is stored. Control to perform a data operation on the flash memory 140. In this case, the data operation may be performed by a physical operation unit of the flash memory 140.

The configuration and operation of the operation controller 120, including the case of performing data operation according to the block state information of the flash memory 140 and the storage state of the internal buffer 130, are described in FIGS. 6 to 8. An example of data operation will be described in detail.

For ease of understanding, it is assumed that the flash memory 140 has the same structure as in FIG. 4. However, it is a matter of course that the embodiments of the present invention also apply to a large block flash memory having a structure different from that of the flash memory described with reference to FIG. 4.

In addition, it is assumed that the internal buffer 130 has the same storage capacity as the physical operation unit of the flash memory 140. In this case, the internal buffer 130 is equal to the size of the page of the flash memory 140. However, even when the internal buffer 130 has a storage capacity of more than twice the logical operation unit of the flash memory 140, the configuration and operation of the internal buffer 130 can be easily understood by those skilled in the art. It is obvious that implementation is possible.

FIG. 6 illustrates a state machine applied to the operation control unit 120 of FIG. 5.

First, block state information is defined by dividing a block of a flash memory into a first type block (hereinafter referred to as 'M block') and a second type block (hereinafter referred to as 'N block').

The M block may mean a block having the same logical page offset lpo, logical sector offset lso, physical page offset ppo, and logical sector offset pso in the block. In this case, all data written in the M block may be interpreted as meaning that they are written in-place. Additionally, even if a block in the flash memory is expected to maintain an M block state, it may be defined as an M block. For example, if there is no data stored in the block at all, when the data is input by the operation request, it can be classified as M block because it is expected to maintain the M block state.

The N block may mean a block in which at least one data stored in the block is written out-of-place. That is, at least one of the data stored in the block is a case where the logical page offset lpo, the logical sector offset lso, the physical page offset ppo, and the logical sector offset pso are stored at different positions. In addition, it can be defined as N block even if a block in the flash memory is surely expected to maintain the N block state.

For example, while the block remains in the M block state, the data that is expected to be stored by the write operation request is stored only in the internal buffer and not in the block of flash memory, but is out-of-place. If it is definitely expected to be stored in N), that is, if it is expected to be changed to N block state, it can be classified as N block. However, this case may be divided into M blocks when strictly based on data stored in a block.

In the example of FIG. 4, a block having a physical block number pbn = 5 has a second write operation request 'write (8, D ₈ ), write (9, of a write operation request having the same logical sector number (8, 9). D ₉ ) 'can be divided into N blocks because the data on which the operation is performed is written in an in-place and out-of-place position. That is, in the example of FIG. 4, the previous six write operations are written in position, and the last two operations are out-of-position because the logical sector offset lso and the physical sector offset pso are different. place)

The block state of the flash memory divided into the M block and the N block may be further divided according to the data storage state of the internal buffer 130 to be divided into M ₀ to M ₃ and N ₀ to N ₃ blocks.

Here, the M ₀ block is an M block in which no data is stored in the internal buffer 130, and the M ₁ block refers to an M block in which one data is stored in the internal buffer 130. And M ₂ block is a block of M, if the two data could block M stored in the case and, in the case of M ₃ is the block 3 of data to the buffer 130 is stored in the buffer 130. The Similarly, N ₀ block means N block without any data stored in the internal buffer 130, and N ₁ block has one data stored in the internal buffer 130, two N ₂ blocks, and _three N ₃ blocks. May mean N blocks. Here, one data may mean data corresponding to one sector size. That is, data stored in one sector may be represented as one data.

The block state segmentation described above is based on the number of data stored in the internal buffer. However, according to another exemplary embodiment, the block state may be subdivided based on the logical sector offset lso of data last stored in the internal buffer, rather than the number of data stored in the internal buffer.

For example, the M block is as follows. M ₁ block is an M block when data corresponding to the logical sector offset (lso) = 0 is stored in the internal buffer, and M ₂ block is an M block when data corresponding to the logical sector offset (lso) = 0 is stored in the internal buffer. M block. Also. The M ₃ block is an M block when data corresponding to logical sector offset (lso) = 2 is stored in the internal buffer, and the M ₀ block includes a state in which there is no data stored in the internal buffer, so that the logical sector offset (lso) = This is an M block when there is no data stored in the internal buffer after data corresponding to 3 is input and all data is written to a position corresponding to the flash memory. The data corresponding to the logical sector offset (lso) = 3 may be written directly to the corresponding location of the flash memory through or without storing the internal buffer. In addition, the data operation on the flash memory may be targeted to all data stored in the internal buffer and input data.

The block segmentation described above is due to assuming four sectors per page of the flash memory. Therefore, when the number of sectors per page of the flash memory has a number other than four, it is apparent that the states of the M block and the N block can be subdivided correspondingly. In addition, even if the storage capacity of the internal buffer has a storage capacity that is not the same as the physical operation unit of the flash memory 140, it is apparent that the state of the M block and the N block can be subdivided correspondingly. This can be easily solved through a simple application by those skilled in the art.

In the case of the M block, the state machine of FIG. 6 subdivides the block state based on the logical sector offset lso of the data last stored in the internal buffer. It is subdivided into.

Alternatively, the state of the M block may be subdivided based on the number of data stored in the internal buffer, and the state of the N block may be subdivided based on the logical sector offset lso of the data last stored in the internal buffer. .

In the state machine of FIG. 6, a number and a letter (for example, 3 / F, 1 / B) indicated by a symbol mean a logical sector offset lso calculated by the input logical sector number lsn. , The letter 'F' means that data operation on the flash memory is performed, and the letter 'B' means that data operation on the flash memory is not performed and data is stored in the internal buffer.

For example, in the state machine, when a symbol of '3 / F' is received, when the logic sector offset (lso) = 3 is received in the M ₀ block state, data stored in the internal buffer is written to the flash memory, and the corresponding memory of the flash memory is written. The state of the block means that the state is M ₀ . In addition, in the case of M ₁ , M ₂ , and M ₃ block states, when the logic sector offset (lso) = 3 is input, data stored in the internal buffer is written to the flash memory, and the state of the corresponding block of the flash memory is M ₀ . It means. This is because the last value of the logical sector offset lso is input. That is, since the number of sectors per page is assumed to be 4, the logical sector offset (lso) value '3' is the last value of the logical sector offset (lso) value. Therefore, when a smaller logical sector offset value is input later, the state is changed to N blocks or the physical page offset (ppo) value is changed (since the target page is changed). Regardless, the data operation on the flash memory is performed.

Here, even when the value of the logical sector offset value is smaller than the previous input value, unless the value of the logical sector offset (lso) value '3' is input, the data is stored in the flash memory after the data is filled in the internal buffer. You can also perform data operations on.

In the case of the N ₃ block, when the logic sector offset (lso) = 3 is input, the data stored in the internal buffer is written to the flash memory, and the state of the corresponding block of the flash memory is the N ₀ block state.

As another example, when the symbol '2 / B' receives an input of logical sector offset (lso) = 2 in the case of M ₀ block, the operation target data is stored in the internal buffer and the state of the corresponding block in the flash memory is M _3. In case of M ₁ block, if the logical sector offset (lso) = 2 is received, the operation target data is stored in the internal buffer, and the state of the corresponding block in the flash memory is M ₃ block state. Means that. In addition, in the case of the M ₂ block, when a logic sector offset (lso) = 2 is received, it means that the operation target data is stored in the internal buffer and the state of the corresponding block of the flash memory is the M ₃ block state.

And the symbol '2 / B' receives a logical sector offset (lso) = 2 input in the case of N ₀ blocks, storing the calculated object data in the buffer and the status of the corresponding block of the flash memory is that the N ₁ block status In the case of the N ₁ block, when the logical sector offset (lso) = 2 is received, the operation target data is stored in the internal buffer and the state of the corresponding block of the flash memory is the N ₂ block state. In addition, in the case of the N ₂ block, when the logical sector offset (lso) = 2 is received, it means that the operation target data is stored in the internal buffer and the state of the corresponding block of the flash memory is the N ₃ block state.

As a result, it can be seen that in the state machine of FIG. 6, when the input of the logical sector offset lso is sequential, the state of the first M block is maintained in the M block state, and when it is not sequential, it is transitioned to the N block state.

The operation of data operation will be described in more detail with reference to the actual operation examples of FIGS. 7 to 8. In the example of FIGS. 7 and 8, it is assumed that logical block number lbn = 0 is mapped to physical block number pbn = 0.

As shown in Fig. 7A, when the logical sector number lsn = 0 is initially input, the logical block number lbn = 0, logical page offset lpo = 0, logical sector offset lso = It becomes 0 and the operation target data is stored in an internal buffer. The block state at this time is M ₁ block state. At this time, the internal buffer has variables of physical block number (PBN) and physical page offset (PPO) (or physical page number (PPN)), and the values of the variables mean a location where the contents of the current internal buffer are used in the flash memory. . Therefore, in the case of FIG. 7A, PBN = 0 and PPN = 0.

As shown in FIG. 7B, a case in which logical sector numbers lsn are input in the order of 0, 1, 2, 3, and 4 will be described. In this case, the operation target data is stored in the internal buffer until the moment when the request for the logical sector number lsn is 0, 1, 2 is input. After the logical sector number (lsn) = 3 request is entered, the capacity of the internal buffer is filled, so the data stored in the internal buffer and the requested operation data with the logical sector number (lsn) = 3 is flashed Will be written to memory. After that, a value of logical sector number lsn = 4, that is, a target data is stored in an internal buffer.

In this case, the operation target data requested with the logical sector number lsn = 3 may be stored in the internal buffer and used in the flash memory, or may be directly written to the flash memory without being stored in the internal buffer. The same applies to the subsequent operation. That is, when it is expected that the capacity of the internal buffer will be full, whether or not the last data is stored in the internal buffer may vary depending on the design situation.

In this case, since one data is stored in the internal buffer, and all of them are stored in place, the block state is M ₁ block. In this case, the logical sector offset lso is a reference value, and since the logical sector offset lso value 0 is input, the block state is M ₁ block.

7C shows an example in which the block state of the flash memory is changed from the M block state to the N block state.

As shown in FIG. 7C, when the logical sector number lsn comes in the order of 0, 1, 0, the operation target corresponding to the first and second requests 0 and 1 of the logical sector number lsn. Data is stored in the internal buffer. The block state at this time is M ₂ block state. After that, in the request of the third logical sector number (lsn) = 0, the block state is changed to the N ₁ block state, and the corresponding second operation target data D ₀ is used in the internal buffer. Meanwhile, the operation target data D ₀ and D ₁ corresponding to the first and second requests 0 and 1 of the logical sector number lsn previously stored in the internal buffer are the first physical page (physical page offset value) of the flash memory. Page 0). This is to reduce the complexity of the algorithm, in which case the block state can be maintained in the M block state (M ₁ block state) without changing to the N ₁ block state.

The second operation target data D0 corresponding to the third request 0 of the logical sector number lsn is determined for the corresponding page (page whose physical page offset value is 1) according to the request state thereafter (FIG. 7 (d)).

FIG. 7D illustrates an example in which an operation request is continuously input following FIG. 7C.

As shown in Fig. 7 (d), the operation request is continuously input in the order of logical sector numbers lsn 0, 1, 1, following Fig. 7 (c). In this case, the calculation target data D ₀ and D ₁ corresponding to the previous logical sector number lsn 0,1 are continuously stored in the internal buffer. Thereafter, the internal buffer is filled at the moment when the last logical sector number (lsn) = 1 is input, so that a write operation to the flash memory is performed. The state of the block at this time becomes the N ₀ block state.

8 (a) and 8 (b) show an example in which the calculation target block of the flash memory is changed.

As shown in FIG. 8A, the logical sector numbers lsn are sequentially input in the order of 4, 5, 6, and 7, and then the second logical sector number lsn 4 is input thereto. At this time, the operation target data D ₄ , D ₅ , D ₆ , and D ₇ corresponding to the sequentially input logical sector numbers (lsn) 4, 5, 6, and 7 are stored in the internal buffer, and the logical sector number (lsn) 7 When is input, it is written to the position of the second physical page (page number (PPN) = 1) of the flash memory. As a result, the block state becomes the M ₀ block state. Thereafter, when the second logical sector number (lsn) 4 is input, the corresponding operation target data D ₄ is stored in the internal buffer, and the block state is changed from M ₀ to N ₁ block state. In this case, the block state may also be changed to the M block state (M ₁ block state) instead of the N ₁ block state.

FIG. 8B illustrates an example in which an operation request is continuously input following FIG. 8A.

As shown in Fig. 8B, the logical sector number lsn 16 is input following Fig. 8A. At this time, the operation target data D4 corresponding to the second logical sector number lsn 4 in FIG. 8A and stored in the internal buffer is the physical page number PPN of the physical block number PBN 0 of the flash memory. It is used at the position of. Data D ₁₂ , D ₁₃ , D ₁₄ , and D ₁₅ are already written in the position of the physical page number (PPN) = 0 of the physical block number PBN 1 of the flash memory.

The logical sector number lsn = 16 is obtained by a logical block number lbn = 1, a logical page offset lpo = 1, and a logical sector offset lso = 0. Assuming that logical block number lbn = 1 is mapped to physical block number pbn = 1, the calculation target data D16 corresponding to logical sector number lsn 16 has a physical page offset of physical block number pbn = 1. (ppo) = 1, the physical sector offset (pso) = 0 is the position. In the given example, since the corresponding position is empty and the block state is M ₀ block state, the block state changes to M1 and the operation target data D ₁₆ is written to the internal buffer. Depending on whether the subsequent input of the logical sector number (lsn) is sequential or not sequential, whether the data to be input later is stored in the internal buffer or used in the physical sector in the corresponding physical page of the flash memory Will be determined.

There may be various examples in addition to the calculation and mapping examples described with reference to FIGS. 7 to 8, but these examples may be easily understood and applied by those skilled in the art. It will be omitted.

In the above, the write operation during the data operation of the flash memory has been described, but it is similarly applicable to the read operation. In the case of read operation, however, the internal buffer may or may not be used. For example, when logical sector numbers for read operations are sequentially input, all data in a page may be read and stored in an internal buffer first, and data operations may be performed by reading corresponding data from the internal buffer. have.

Regardless of whether the internal buffer is used or not, in the case of the read operation, when the block state of the flash memory is M block, data of the position may be read. In the case of N block, the operation information stored in the spare area is reversed. Scanning is performed to read the most recently stored data at the location.

As described above, according to the present invention, by performing data operation and mapping using the change of the internal buffer and the block state, it is possible to efficiently apply to the large block flash memory.

In the description of the present invention, the terms logical sector number, page number, etc. are used, but they may be replaced with the term address generally used in memory. In addition, in the present invention, the above-described configuration is illustrated as being applied to a large block flash memory, but the present invention may be less effective, but may be applied to a small block flash memory, and may be applied to other memory devices other than the flash memory. It may be applicable through application or modification.

The description of the above embodiments is merely given by way of example with reference to the drawings for a more thorough understanding of the present invention, and should not be construed as limiting the present invention. In addition, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the basic principles of the present invention.

1 is a block diagram of a typical flash memory system.

2 is a diagram showing the structure of a small block flash memory and a large block flash memory;

3 is a view for explaining an example of a data operation and mapping method in a general small block flash memory system.

4 is a view for explaining an example of a data operation and mapping method of a large block flash memory according to an embodiment of the present invention.

5 is a block diagram of a flash memory system according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating a state machine applied to the operation control unit 120 of FIG. 5.

7 to 8 are diagrams showing data operation operations through actual calculation examples.

* Description of the symbols for the main parts of the drawings *

100: flash memory system 120: operation control unit

130: internal buffer 140: flash memory

Claims (22)

In a flash memory system: And a plurality of blocks, each of the plurality of blocks having a plurality of pages, each of the plurality of pages having a plurality of sectors, and having a larger capacity of a physical operation unit than a logical operation unit. A large block flash memory having a storage capacity and storing block state information and operation information for each of the plurality of blocks therein; An internal buffer having a storage capacity corresponding to n times a storage capacity of a physical operation unit of the flash memory (n is a natural number), and for temporarily storing data for a data write operation to the flash memory; The data desired for the operation is first stored in the internal buffer, and according to the block state information of the flash memory and the data storage state of the internal buffer, the data operation of the data stored in the internal buffer into the corresponding block of the flash memory. It is provided with an operation control unit for controlling the performance, The blocks of the flash memory may include at least one of a first type block (M block) in which page offsets and a sector offset coincide, or a second type block including data in which page offsets and sector offsets do not coincide. Divided into (N blocks), wherein the block state information includes information of the first type block and information of the second type block, The logical operation unit of the flash memory is a sector, the physical operation unit is a page, and the block state information of the flash memory is stored in a meta block storing information on the flash memory or stored in each block. Flash memory system. The method according to claim 1, The operation control unit preferentially stores calculation target data in the internal buffer, and at least data of a storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory is stored in the internal buffer; or And performing a data operation on the block of the flash memory of data stored in the internal buffer when the operation target physical page is changed. The method according to claim 1, The operation control unit, First, the operation target data to be input is stored in the internal buffer, According to whether the internal buffer has stored at least as much data as the storage capacity corresponding to n times the physical operation unit of the flash memory (n is a natural number) and whether the logical sector offset corresponding to the operation target data is sequentially inputted, And performing a data operation on the corresponding block of the flash memory of data stored in the internal buffer or inputted operation data. The method according to claim 1, The operation control unit, When the block of the flash memory is expected to hold the first type block or to hold the first type block, and when it is expected to keep the second type block continuously or to maintain the second type block, the When at least as much data as the storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory is stored in the internal buffer or when the physical page offset value is changed, the data stored in the internal buffer or input Perform a data operation on the corresponding block of the flash memory of the association data; In the case of the calculation target data input, in which the block of the flash memory is expected to be changed or changed from the first type block to the second type block, the block to the associative target data or the internal buffer inputted at the time of the calculation target data input. And performing a data operation on the corresponding block of the flash memory. In the data operation method of the flash memory: The operation target data to be operated is preferentially stored in an internal buffer having a predetermined storage capacity, and the internal buffer has at least as much data as the storage capacity corresponding to n times (n is a natural number) of the physical operation unit of the flash memory. Depending on whether the stored or physical page offset value is changed, it is determined whether to perform data operation on the flash memory of the data stored in the internal buffer or the input operation target data. And the flash memory is a large block flash memory having a larger capacity of a physical operation unit than a logical operation unit. In the data operation method of the flash memory: Inputting a logical sector number and operation target data; Storing the operation target data in a predetermined order in an internal buffer having a storage capacity corresponding to n times (n is a natural number) of the storage capacity of the physical operation unit of the flash memory; The blocks of the flash memory may be divided into a first type block in which all stored data coincide with a page offset and a sector offset, or a second type block including at least one of data stored in which the page offset and sector offset do not match. Perform a data operation on the flash memory of the data stored in the internal buffer or input operation data; If the input of the logical sector offsets calculated through the logical sector number is sequential, the data operation is performed to maintain the first type block, and if the input of the logical sector offsets is not sequential, the data operation is transferred to the second type block. And performing a step The flash memory is a large block flash memory having a larger capacity of a physical operation unit than a logical operation unit, and the data operation to the flash memory is n times the physical operation unit of the flash memory to the internal buffer. Is performed in the unit of physical operation when at least data corresponding to the storage capacity corresponding to the natural number) is stored or when the physical page offset value changes. A logical operation unit of the flash memory is a sector, a physical operation unit is a page, and the data operation is a data write operation. In the mapping control method of flash memory: Inputting a logical sector number for data operation; When the logical sector number is lsn, the logical block number is lbn, the logical page offset is lpo, the logical sector offset is lso, the number of pages per unit block is np, and the number of sectors per unit page is ns. obtaining the logical block number, the logical page offset, and the logical sector offset value by / (np * ns), tmp = lsn% (np * ns), lpo = tmp / ns, and lso = tmp% ns; ; Retrieving a physical block corresponding to the logical block number according to a predefined mapping table; In principle, data mapping is performed at a position of a physical page offset and a physical sector offset coinciding with the logical page offset and the logical sector offset, but the physical page offset and the physical page offset coincide with the logical page offset and the logical sector offset. If the data is already stored in the position of the sector offset, and performing the mapping for the data operation to the adjacent position or any position, The flash memory has a plurality of blocks, each of the plurality of blocks includes a plurality of pages, each of the plurality of pages has a structure having a plurality of sectors, and is physically larger than the sector, which is a logical operation unit. And a large block flash memory having a larger capacity of the page as an operation unit. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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