KR20100006625A - Apparatus and method for managing page buffer linked with flash memory and apparatus and method for changing page of flash memory - Google Patents

Abstract

PURPOSE: An apparatus and a method for managing a page buffer linked with a flash memory and an apparatus and a method for changing a page of a flash memory are provided to improve performance of the flash memory, increase a buffer hit rate and extend lifetime of the flash memory. CONSTITUTION: A buffer unit(210) stores data of a page unit read from a flash memory. If the amount of data saved in the buffer unit becomes a reference amount, a buffer managing unit(220) selects replaced data among the data saved in the buffer unit to remove it. A page list managing unit(230) generates a clean page list and a dirty page list and deletes a page index corresponding to target data to be replaced.

Description

Apparatus and method for managing page buffer linked with flash memory and apparatus and method for changing page of flash memory}

The present invention relates to an apparatus and method for managing a page buffer interoperating with a flash memory, and an apparatus and method for replacing a page of a flash memory, and more particularly, to store data in which a read operation and a write operation are performed by reading from a NAND flash memory. The present invention relates to an apparatus and a method for replacing data in a page buffer.

Flash memory, a type of nonvolatile memory, is divided into a NOR type used for storing code and a NAND type used as a data storage device. NAND flash memory consists of contiguous blocks of the same size, and one block consists of contiguous pages of size generally 512 bytes. There are three operations that can be performed in flash memory: read, write and erase. Read and write operations are performed in units of pages, and erase operations are performed in units of blocks. At this time, the write operation takes more time than the read operation and causes an erase operation that requires more execution time than the write operation. Therefore, reducing the number of write operations improves the overall performance of the flash memory.

Unlike hard disks, flash memory has unique characteristics. First, pages targeted for write operations must be erased in advance. Therefore, in-place update is impossible, and when a page is modified, a new physical page must be allocated to perform a write operation. Second, the number of erase operations that can be performed in the flash memory is generally limited to 100,000 or less. Therefore, the more write operations are performed, the more erase operations are performed, which shortens the life of the flash memory.

Read and write operations in flash memory are performed through the buffer. A buffer is a memory that compensates for the speed between a very fast central processor and a very slow auxiliary memory. Some areas of computer main memory are used as buffers, or memory added separately to flash memory storage is used as a buffer. After the page of the flash memory on which the write operation is to be performed is loaded into the buffer, the record to be written to the flash memory is stored in the buffer. Later, when the buffer becomes full, certain pages are replaced to free up space. At this time, if the data of the replaced page is changed, the changed contents are written to a new page of the flash memory through a write operation.

Existing buffer management techniques for determining pages to be replaced include First-In, First-Out (FIFO), Least Recently Used (LRU), Least Frequently Used (LFU), and Most Recently Used (MFU). These techniques use the time of buffer storage, the elapsed time after buffer storage, and the number of times that the data is referenced after deciding to replace the data among the pages of the memory buffer. The FIFO technique first replaces the page loaded in the buffer first, and the LRU technique first replaces the oldest page after a write operation. The LFU technique preferentially replaces pages with the least number of write operations, and the MFU technique preferentially replaces pages with the highest number of write operations.

FIG. 1 is a diagram illustrating a configuration of a buffer management system using an LRU method among existing buffer management techniques.

Referring to FIG. 1, in a buffer management system using an LRU method, information about each page is sequentially stored from a page buffer 110 in which data in units of pages is stored and a page on which a write operation is most recently performed. It consists of a page list 120. Information about the page stored in the page list 120 includes a page number and whether a write operation has been performed. If a write operation is performed on data corresponding to each page number, it is indicated as dirty (D). If only a read operation is performed, it is indicated as clean (C).

When replacing pages stored in the page buffer 110 using a buffer management system using the LRU method, the oldest pages are replaced after a read or write operation is performed, regardless of whether each page is dirty or clean. Select and remove as target data. In this case, when the dirty page is removed, a process in which data is stored in the flash memory by a write operation is required. Since the process is performed in units of blocks, performance is degraded because the speed is slower than that of clean pages. As such, the existing page replacement technique has a problem of degrading flash memory performance and shortening its lifespan.

It is an object of the present invention to provide a page buffer management apparatus and method for improving the performance of a flash memory, increasing the buffer hit ratio, and extending the life of the flash memory.

Another technical problem to be solved by the present invention is to provide a computer-readable recording medium having recorded thereon a program for executing a page buffer management method that can improve flash memory performance, increase buffer hit ratio, and extend flash memory life. To provide.

Another object of the present invention is to provide an apparatus and a method of replacing a page of a flash memory that can improve the performance of the flash memory by reducing the number of write and erase operations on the flash memory.

Another technical problem to be solved by the present invention is to read a computer program for executing a page replacement method of a flash memory that can improve the performance of the flash memory by reducing the number of write and erase operations on the flash memory. To provide a record carrier.

In order to achieve the above technical problem, a page buffer management apparatus interoperating with a flash memory according to the present invention includes a buffer unit configured to store data in units of pages read from a flash memory; A buffer manager which selects replacement target data from data in units of pages stored in the buffer unit and removes it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; A page index for a clean page on which a read operation is performed and a block number to which the block number to which the clean page belongs is recorded, and a page index on a dirty page on which a write operation is performed; And a page list manager which generates a dirty page list for recording the block number to which the dirty page belongs and deletes the page index corresponding to the replacement target data.

According to another aspect of the present invention, there is provided a page buffer management method interoperating with a flash memory, the buffer unit updating step of storing data in a buffer unit in which data in units of pages read from a flash memory is stored; A buffer management step of selecting replacement target data from data of a page unit stored in the buffer unit and removing it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; A page index for a clean page on which a read operation is performed and a block number to which the block number to which the clean page belongs is recorded, and a page index on a dirty page on which a write operation is performed; And a page list management step of generating a dirty page list for recording the block number to which the dirty page belongs, and deleting the page index corresponding to the replacement target data.

In accordance with another aspect of the present invention, there is provided a page replacement apparatus for a flash memory, including: a buffer unit configured to store data in units of pages read from a flash memory; A buffer manager which selects replacement target data from data in units of pages stored in the buffer unit and removes it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And a page list in which a page index of a page unit data stored in the buffer unit, a block number to which each page belongs, and a flag indicating whether to perform a read operation or a write operation are recorded to generate a page list corresponding to the replacement target data. And a page manager to delete the index.

In accordance with another aspect of the present invention, there is provided a method of replacing a page of a flash memory, the buffer unit updating step of storing data in a buffer unit in which data in units of pages read from the flash memory is stored; A buffer management step of selecting replacement target data from data of a page unit stored in the buffer unit and removing it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And a page list in which a page index of a page unit data stored in the buffer unit, a block number to which each page belongs, and a flag indicating whether to perform a read operation or a write operation are recorded to generate a page list corresponding to the replacement target data. Page management step of deleting an index.

According to the apparatus and method for managing a page buffer interoperating with a flash memory according to the present invention, by separately managing clean pages and dirty pages, data on which write operations are performed remain in the page data for a long time, thereby increasing the buffer hit ratio. Furthermore, by replacing data belonging to the same block when replacing data on which write operations have been performed, the number of times of erase operations is reduced due to the characteristics of the flash memory in which erase operations are performed block by block, thereby extending the life of the flash memory. have. In addition, according to the apparatus and method for replacing a page of a flash memory according to the present invention, by replacing the data belonging to the same block when replacing the data on which the write operation is performed, the flash memory by reducing the number of write and delete operations to the flash memory Can improve the performance.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the page buffer management apparatus and method, and the page replacement apparatus and method of the flash memory according to the present invention. First, in designating reference numerals to components of each drawing, the same components have the same number even though they are displayed on different drawings.

2 is a block diagram showing the configuration of a preferred embodiment of the page buffer management apparatus according to the present invention.

2, a page buffer management apparatus according to the present invention includes a buffer 210, a buffer manager 220, and a page list manager 230.

The buffer unit 210 stores data in units of pages read from the flash memory. Before the write and delete operations are performed on the flash memory, writing and deleting of page data stored in the buffer unit 210 are performed first. The reading and writing of page data with respect to the flash memory is performed in units of pages, and the erasing operation is performed in units of blocks including a plurality of pages.

When the amount of data stored in the buffer unit 210 reaches a preset reference capacity (for example, 90% of the buffer capacity), the buffer manager 220 replaces the data among page data stored in the buffer unit 210. The data is selected and removed from the buffer unit 210.

If data to perform a read operation or a write operation is not stored in the buffer unit 210, the data should be read from the flash memory. The data read operation may be performed by the buffer manager 220. In addition, the buffer unit 220 stores the changed data again in the buffer unit 210 when the write operation is performed on the data stored in the buffer unit 210, and deletes and writes the flash memory when the stored data is removed. Do this.

The operation of reading data from the flash memory and the deleting and writing of the flash memory may be performed by using a separate device such as a memory driver (not shown) instead of the buffer manager 220. In this case, the memory driver (not shown) receives a request from the buffer manager 220 that data to be performed is not stored in the buffer unit 210 and therefore needs to be read from the flash memory, and reads data from the flash memory. The buffer 210 stores the same. In this case, when the amount of data stored in the buffer unit 210 reaches the reference capacity, the buffer manager 220 stops the operation of the memory driver (not shown) and removes the replacement target data from the buffer 210. When the data to be removed is data in which a write operation is performed, the buffer manager 220 requests a memory driver to delete and write data to the memory driver (not shown), and the memory driver (not shown) to the flash memory. Performs delete and write operations.

The page list manager 230 may include a clean page list in which a page index and a block number to which a clean page belongs to a clean page of a page unit stored in the buffer unit 210 are recorded, and a write operation is performed. A dirty page list for recording the page index for the dirty page and the block number to which the dirty page belongs is generated, and the page index corresponding to the replacement target data is deleted.

When the amount of data stored in the buffer unit 210 reaches the reference capacity and the buffer management unit 220 selects and removes the replacement target data and delivers it to the page list management unit 230, the page list management unit 230 replaces the replacement target data. The page index corresponding to the data is deleted from the page list.

On the other hand, even if the amount of data stored in the buffer unit 210 does not reach the reference capacity, when the number of page indexes recorded in the clean page list or the dirty page list reaches the reference number, the page list manager 230 The buffer management unit 220 requests the selection of the replacement target data. The buffer manager 220 selects replacement target data from the page indexes recorded in the clean page list or the dirty page list, and the page list manager 230 deletes the page index corresponding to the selected replacement target data.

3 is a view for explaining an operation of managing a page buffer using the page buffer management apparatus according to the present invention.

Referring to FIG. 3, data configured in units of pages read from the flash memory is stored in the buffer unit 210, and the buffer unit 210 is included in the page lists 310 and 320 generated by the page list manager 230. Information about the stored page data is recorded.

In the clean page list 310, a page index for a clean page, which is page data on which a read operation is performed, and a block number to which each clean page belongs, are recorded. In the dirty page list 320, dirty, which is page data on which a write operation is performed, The page index for the page and the block number to which each dirty page belongs are recorded. In this case, when the buffer management unit 220 uses the LRU, which is one of methods for selecting replacement target data, the page lists 310 and 320 may display information about each page data according to a time point at which a read operation or a write operation is performed. Are written sequentially.

The size of the clean page list 310 and the dirty page list 320 is 1 when the size of the page list used in the system according to the conventional LRU method is 1, and the ratio of the dirty page list 320 is α (0 <α <1). ), The ratio of the clean page list 310 may be set to 1-α. Although the size of the dirty page list 320 may be arbitrarily determined, however, when the size of the dirty page list 320 is too small, frequent replacement of page data may occur, which may degrade the performance of the flash memory. desirable.

By generating the clean page list 310 and the dirty page list 320 separately in this manner, separate identification marks as to whether to perform a read operation or a write operation, such as page data recorded in the conventional page list 120, are performed. There is no need to record it.

The page list manager 230 generates the clean page list 310 and the dirty page list 320 and deletes the page indexes of the replacement target data selected by the buffer manager 220 from the page lists 310 and 320. do.

When the combined capacity of the amount of data originally stored in the buffer unit 210 and the amount of data read out from the flash memory reaches the reference capacity, a space for storing new data read out from the flash memory is required. Should be performed. The replacement operation is performed by selecting and removing replacement target data, which is data to be removed, from the data stored in the buffer unit 210. The replacement target data may be selected using conventional buffer management techniques such as FIFO, LRU, LFU, MFU, and the like. When using the LRU method, the buffer manager 220 selects the oldest page data as replacement target data after a read operation or a write operation is performed among the page data recorded in the page lists 310 and 320.

In addition, when the replacement target data selected by the buffer management unit 220 is a dirty page, since the erase operation for the flash memory is performed in units of blocks, the dirty pages having the same block number as the selected replacement target data are also selected as replacement target data. Removing can reduce the number of erase and write operations to flash memory.

The page replacement operation is performed by the number of page indexes and the page list 310 written in the clean page list 310 or the dirty page list 320 even when the amount of data stored in the buffer unit 210 does not reach the reference capacity. It may also be performed when the number of pages plus the number of pages for data to be recorded in 320 reaches a preset reference number.

When data to be read or written is not stored in the buffer unit 210 and data is to be read from the flash memory, the data may be immediately stored if there is a storage space in the buffer unit 210. However, when a page index is to be written to the clean page list 310 or the dirty page list 320 by performing a read operation or a write operation on data read from the flash memory, the page list 310 may be written by writing the page index. When the number of page indexes recorded in 320 reaches a reference number, the recorded page indexes should be deleted.

At this time, the process of selecting the replacement target data among the page indexes recorded in the clean page list 310 or the dirty page list 320 is performed by the buffer manager 220. It is the same as selecting data to be replaced when the quantity reaches the reference dose.

On the other hand, when data to perform a read operation or a write operation is not stored in the buffer unit 210 and the data is read from the flash memory, the data read process is interpreted as a read operation to read the data from the buffer unit It is also possible to record the page index for the data read in the clean page list 310 and stored at 210. Even in this case, although there is a storage space in the buffer unit 210, the number of page indexes recorded in the clean page list 310 reaches a reference number and thus may require the deletion of the page index.

If the page data to be written is already stored in the buffer unit 210, if the stored page data is recorded in the dirty page list 320, the dirty page list 320 is performed after a write operation is performed to the page data. You only need to move the location within the record. However, when the page data to be written is a clean page, the page data is changed to a dirty page, so the page data information needs to be moved from the clean page list 310 to the dirty page list 320. To this end, the page list manager 230 deletes the page index for the clean page on which the write operation is performed, from the clean page list 310 and adds the dirty page list to the dirty page list 320.

In this case, when the number of page indexes stored in the dirty page list 320 reaches a preset reference number due to the movement of the page index, replacement target data among the dirty pages stored in the dirty page list 320 for page data to be recorded later. To be removed. Among the existing buffer management techniques, when the LRU method is used, the oldest dirty page is selected as the replacement data after the write operation, and even in this case, the dirty data having the same block number as the selected replacement data is replaced together. By selecting and removing, the performance of flash memory can be improved.

4A is a flowchart illustrating a process of performing a preferred embodiment of the method for managing a page buffer according to the present invention, and FIG. 4B is a page unit for storing data in a buffer unit in a page buffer management method according to the present invention. In this case, a flowchart showing a process of performing a preferred embodiment is shown.

4A and 4B, when a work request for data in units of pages stored in the flash memory is input from the outside, the buffer manager 220 searches whether the data to be performed is stored in the buffer 210. (S405). If the requested data is not stored in the buffer unit 210 (S410), the data should be read from the flash memory and stored in the buffer unit 210. In this case, the buffer manager 220 checks whether the sum of the amount of data stored in the buffer unit 210 and the amount of data read from the flash memory reaches a preset reference capacity (S415), and when the reference capacity is not reached. In the buffer unit 210 stores data in units of pages read from the flash memory.

In addition, the operation of storing data in the buffer unit 210 may be performed by a separate device such as a memory driver (not shown) instead of the buffer manager 220. In this case, the memory driver (not shown) stores the changed data in the flash memory or reads data from the flash memory and stores the changed data in the buffer 210.

When the sum of the amount of data stored in the buffer unit 210 and the amount of data read out from the flash memory reaches a preset reference capacity, data cannot be stored in the buffer unit 210 anymore, so the buffer manager 220 ) Selects the replacement target data to be removed from the buffer unit 210 to secure the storage space (S420). In order to improve the performance of the flash memory, the replacement target data is preferably selected among the clean pages recorded in the clean page list 310, and the oldest page may be selected as the replacement target data after the read operation is performed. When the replacement target data is selected from the dirty pages (S425), the dirty pages belonging to the same block as the selected replacement target data are also selected as the replacement target data (S430). The buffer manager 220 removes the selected replacement target data from the buffer 210 (S435), and accordingly, the page index of the replacement target data is deleted from the page lists 310 and 320 by the page list manager 230. FIG. .

 The page list manager 230 checks whether a write operation is performed on the data of the page unit stored in the buffer unit 210 (S440), and even if the amount of data stored in the buffer unit 210 does not reach the reference capacity, the clean page If the sum of the number of page indexes originally recorded in the list 310 or the dirty page list 320 and the number of pages of data read from the flash memory reaches a preset reference number, the buffer management unit 220 replaces the page index. The target page is selected.

If the operation performed on the data stored in the buffer unit 210 is a read operation and the number of page indexes recorded in the clean page list reaches the reference number (S450), the replacement target data is stored in the data recorded in the clean page list. It is selected and removed (S455). In addition, when the operation performed on the data stored in the buffer unit 210 is a write operation, and the number of page indexes recorded in the dirty page list reaches the reference number (S445), the replacement target is among the data recorded in the dirty page list. The data is selected and removed. When the replacement target data is the dirty page, as described above, the dirty pages belonging to the same block as the selected replacement target data may be selected and removed together as the replacement target data to improve the performance of the flash memory (S430).

On the other hand, after storing the data read from the flash memory in the buffer unit 210 and performing a read operation or a write operation, the data is stored in the buffer unit 210 without being written to the page lists 310 and 320, and at the same time, a clean page It is also possible to record to the list 310. In this case, a read operation or a write operation is performed on the data recorded in the clean page list 310, and when the write operation is performed, the page index is moved from the clean page list 310 to the dirty page list 320.

If the data to be performed is already stored in the buffer unit 210, it is not necessary to read the data from the flash memory, and depending on whether a write operation is performed on the already stored page data (S460), the page list manager ( The operation of 230 will be different. When the read operation is performed, since the data stored in the buffer unit 210 does not change, only the position of the page index in the page lists 310 and 320 originally located by the page list manager 230 may be moved (S465). On the other hand, when a write operation is performed on the page data, it is checked whether the original position of the data on which the operation is performed is the clean page list 310 or the dirty page list 320 (S470), and the write operation is already performed to perform the dirty page. When a rewrite operation is performed on the data located in the list 320, only the position of the page index in the dirty page list 320 is moved (S465).

When a write operation is performed on the data of a page unit that is located in the clean page list 310, the type of page data is changed from a clean page to a dirty page. Therefore, the page list manager 230 moves the page index of the page data on which the write operation is performed from the clean page list 310 to the dirty page list 320 (S475). In this case, when the number of page indexes recorded in the dirty page list 320 reaches a preset reference number (S445), the buffer manager 220 selects replacement target data from the data recorded in the dirty page list 320. do. Even in this case, the dirty pages belonging to the same block as the selected replacement target data may be selected as replacement target data to improve the performance of the flash memory (S430). If the selected replacement target data is removed (S435), the page replacement operation is terminated.

5 is a block diagram showing the configuration of a preferred embodiment of a page replacement apparatus of a flash memory according to the present invention.

Referring to FIG. 5, a page replacement apparatus of a flash memory according to the present invention includes a buffer unit 210, a buffer manager 220, and a page replacer 510.

The buffer unit 210 stores data in units of pages read from the flash memory. As with the page buffer management apparatus according to the present invention, writing and erasing of the page data stored in the buffer unit 210 are performed before the write and delete operations are performed on the pages of the flash memory.

The buffer manager 220 may also use the buffer manager 220 used in the page buffer manager according to the present invention. When the amount of data stored in the buffer 210 reaches a preset reference capacity, the buffer manager 210 may be used. The replacement target data is selected from the data of the page unit stored in the &quot; In this case, a separate operation of reading data from the flash memory and deleting and writing the flash memory may be performed by a memory driver (not shown).

In addition, the page replacer 510 generates a page list in which a page index, page number of each page to which each page is stored, and a flag indicating whether a read operation or a write operation is performed are recorded in the buffer unit 210. Delete the page index corresponding to the replacement target data.

Here, the page list generated by the page replacement unit 510 is the same as the page list 120 shown in FIG. 1, and a read operation or a write operation is performed on one list regardless of whether a read operation or a write operation is performed. The page indexes are sequentially recorded according to the time points. Therefore, when the replacement target data is selected by the buffer management unit 220, when the LRU method of the conventional buffer management technique is used, the oldest after the read or write operation is performed regardless of the type of the operation performed on the page data. The page is selected as the replacement target data.

When the data on which the write operation is performed is selected as the replacement target data, the buffer manager 220 selects the data including the page unit having the same block number as the replacement target data as the replacement target data. When the data on which the write operation is performed is removed, erase and write operations are performed on the flash memory. In this case, since the delete operation is performed in units of blocks rather than units of pages, removing pages belonging to the same block at once can reduce the number of erase and write operations to the flash memory, thereby improving the performance of the flash memory.

6 is a flowchart illustrating a process of performing a preferred embodiment of the method of page replacement of a flash memory according to the present invention.

Referring to FIG. 6, when a work request for data in units of pages stored in a flash memory is input from outside, the buffer manager 220 searches whether the data to be performed is stored in the buffer 210 (S610, S615). When the requested data is stored in the buffer unit 210, since a read operation or a write operation is performed on the already stored data, no new storage space is required, and the buffer manager 220 performs a read operation or a write operation. The result may be stored in the buffer unit 210. When the write operation is performed on the page data in which the read operation is performed, the page replacer 510 replaces and writes a flag indicating whether the read operation or the write operation is performed (S620).

If the requested data is not stored in the buffer unit 210, the buffer manager 220 should read data from the flash memory and store the data in the buffer unit 210. If the amount of data stored in the buffer unit 210 does not reach the preset reference capacity (S625), since the storage space of the newly read data remains, the buffer unit 210 stores the data in which the read or write operation is performed. Store in In addition, the page replacement unit 510 writes a page index for the data stored in the buffer unit 210, a block number to which the data belongs, and a flag indicating whether to perform a read operation or a write operation in the page list 120 (S630). .

When the amount of data stored in the buffer unit 210 reaches a preset reference capacity, the buffer manager 220 replaces the data of the page unit stored in the buffer unit 210 to secure a storage space of newly read data. The data is selected (S635). In this case, when the replacement target data is selected from the data on which the write operation is performed (S640), data consisting of page units having the same block number as the selected replacement target data is also selected as the replacement target data (S645). When the write operation is performed, data is deleted and written to the flash memory. Since the delete operation is performed in blocks, selecting and removing replacement target data in blocks reduces the number of erase and write operations. It can improve the performance of memory. When the replacement target data is selected among the data on which the read operation is performed, it is not necessary to select the replacement target data additionally, and the buffer manager 220 removes the selected replacement target data from the buffer 210 and replaces the page replacement unit 510. Deletes the page index of the replacement target data (S650). When the storage space is secured by the process of removing the replacement target data, the buffer manager 220 stores the read data in the buffer 210 and the page replacer 510 stores the page index of the data in the page list 120. Write to (S630).

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all types of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

1 is a diagram illustrating a configuration of a buffer management system using an LRU method among existing buffer management techniques.

2 is a block diagram showing the configuration of a preferred embodiment of a page buffer management apparatus according to the present invention;

3 is a view for explaining an operation of managing a page buffer using a page buffer management apparatus according to the present invention;

4A is a flowchart illustrating a process of performing a preferred embodiment of the page buffer management method according to the present invention;

4B is a flowchart illustrating a process of performing a preferred embodiment in a case where data of a page unit to perform a task is stored in a buffer unit in the method of managing a page buffer according to the present invention;

5 is a block diagram showing the configuration of a preferred embodiment of a page replacement apparatus of a flash memory according to the present invention;

6 is a flowchart illustrating a process of performing a preferred embodiment of the method of page replacement of a flash memory according to the present invention.

Claims (14)

A buffer unit to store data in units of pages read from the flash memory; A buffer manager which selects replacement target data from data in units of pages stored in the buffer unit and removes it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And A page index for a clean page on which a read operation is performed and a block number to which the clean page belongs, and a page index on a dirty page on which a write operation is performed; And a page list manager which generates a dirty page list in which the block number to which the dirty page belongs is recorded and deletes the page index corresponding to the replacement target data. The method of claim 1, And the buffer manager selects the oldest page as the replacement target data after a read operation is performed among the clean pages. The method of claim 1, And the buffer manager selects the replacement target data when the number of page indexes stored in the clean page list or the dirty page list reaches a preset reference number. The method according to claim 1 or 3, And the page list management unit moves a page index for the clean page on which the write operation is performed, from the clean page list to the dirty page list. The method of claim 4, wherein And when the replacement target data is selected from among the dirty pages, the buffer manager selects data including page units having the same block number as the replacement target data as replacement target data. A buffer unit updating step of storing data in a buffer unit in which data in units of pages read from the flash memory is stored; A buffer management step of selecting replacement target data from data of a page unit stored in the buffer unit and removing it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And A page index for a clean page on which a read operation is performed and a block number to which the clean page belongs, and a page index on a dirty page on which a write operation is performed; And a page list management step of generating a dirty page list for recording the block number to which the dirty page belongs, and deleting the page index corresponding to the replacement target data. The method of claim 6, And in the buffer management step, selecting the oldest page as the replacement target data after a read operation is performed among the clean pages. The method of claim 6, And in the buffer management step, selecting the replacement target data when the number of page indexes stored in the clean page list or the dirty page list reaches a preset reference number. The method according to claim 6 or 8, And in the page list management step, move the page index for the clean page on which the write operation is performed from the clean page list to the dirty page list. The method of claim 9, In the buffer management step, when the replacement target data is selected from the dirty pages, the page buffer management method, characterized in that the data consisting of the page unit having the same block number as the replacement target data is selected as the replacement target data. A buffer unit to store data in units of pages read from the flash memory; A buffer manager which selects replacement target data from data in units of pages stored in the buffer unit and removes it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And A page index corresponding to the data to be replaced by generating a page list in which a page index of the page unit data stored in the buffer unit, a block number to which each page belongs, and a flag indicating whether to perform a read operation or a write operation are recorded. It includes; page replacement unit for deleting; When the data on which the write operation is performed is selected as the replacement target data, the buffer manager selects data including page units having the same block number as the replacement target data as replacement target data. Page replacement device. A buffer unit updating step of storing data in a buffer unit in which data in units of pages read from the flash memory is stored; A buffer management step of selecting replacement target data from data of a page unit stored in the buffer unit and removing it from the buffer unit when the amount of data stored in the buffer unit reaches a preset reference capacity; And A page index corresponding to the data to be replaced by generating a page list in which a page index of the page unit data stored in the buffer unit, a block number to which each page belongs, and a flag indicating whether to perform a read operation or a write operation are recorded. A page replacement step of deleting; In the buffer management step, when the data on which the write operation is performed is selected as the replacement target data, the flash memory may select data including a page unit having the same block number as the replacement target data as the replacement target data. How to replace the page. A computer-readable recording medium having recorded thereon a program for executing the page buffer management method according to any one of claims 6 to 9. A computer-readable recording medium having recorded thereon a program for executing the page replacement method of the flash memory according to claim 12 on a computer.

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