WO2004006102A1

WO2004006102A1 - Flash memory management program, flash memory management method, and flash memory management apparatus

Info

Publication number: WO2004006102A1
Application number: PCT/JP2002/006675
Authority: WO
Inventors: Hiroshi Kosaki; Yuuji Nakayama; Honhong Cho
Original assignee: Fujitsu Limited; Fujitsu Peripherals Limited
Priority date: 2002-07-02
Filing date: 2002-07-02
Publication date: 2004-01-15

Abstract

A flash memory management program writes and reads data to/from a flash memory in response to a request from a data management program managing data stored in the flash memory. The program executes a process for managing an erase count of a physical block which is a flash memory erase unit and data updating attribute as block management information and a process for acquiring an empty physical block for storing data according to the physical block erase count and the data updating attribute managed as the block management information.

Description

Description Flash memory management program, flash memory management method, and flash memory management device

Technical field

The present invention relates to a flash memory management program, a flash memory management method, and a flash memory management method for writing and reading denita to and from a flash memory in response to a request from a data management program for managing data stored in the flash memory. Regarding memory management devices, in particular, prevent unequal numbers of erasures of physical blocks due to data that is not updated continuing to occupy physical blocks with fewer erasures of flash memory, and unnecessary data exchange between physical blocks. The present invention relates to a flash memory management program, a flash memory management method, and a flash memory management device that can prevent the occurrence of flash memory and extend the life of the flash memory.

Background art

In recent years, file systems using flash memory have been used for information devices such as mobile phones. In this flash memory, when rewriting data, it is necessary to erase the data in physical block units, and the number of erases is limited. Therefore, the number of erases is equalized so that the number of erases of a specific physical block does not increase. 2. Description of the Related Art There are known conventional techniques.

For example, in Japanese Patent Application Laid-Open No. Hei 6-124649 / Japanese Patent Application Laid-open No. Hei 10-316161, the number of erasures of each physical block is stored, and an empty physical block having a small number of erasures is stored. There is disclosed a technology for equalizing the number of erasures by using locks (hereinafter referred to as “empty blocks”).

However, if you decide to simply use a free block with a small number of erases, However, if data that is not updated is written to a physical block, the physical block is not updated and erased even if the number of times of erasure of that physical block is less than the number of times of erasure of other physical blocks. There is a problem that the number of times cannot be equalized. For example, if the data that occupies half of the flash memory is not updated, the life is halved because the other half is repeatedly erased.

Japanese Patent Laid-Open Publication No. Hei 6-222 986 proposes to solve the problem when the number of erasures of a certain physical block is equal to or greater than a predetermined value, or the number of erasures and the number of erasures of this physical block. When the difference between the number of erasures of the physical block with the least number of erasures is equal to or greater than a predetermined value, the number of erasures is equalized by exchanging the data of this physical block with the data of the physical block with the least number of erasures. The technology is disclosed. '' However, if the data of a physical block with a large number of erasures and the data of a physical block with a small number of erasures are simply exchanged using this conventional technology, the number of erasures from the physical block with a large number of There is an efficiency problem that the physical block is moved to a physical block with less data. In other words, even though data that is not updated should be used as it is, a physical block with a large number of erasures should be used, but it is moved to a physical block with a small number of erasures, causing unnecessary data exchange and reducing efficiency At the same time, the life of the flash memory is shortened. Therefore, the present invention prevents unequal number of erasures of a physical block due to data that is not updated continuing to occupy a physical block with a small number of erasures of the flash memory, and prevents unnecessary data between physical blocks. An object of the present invention is to provide a flash memory management program, a flash memory management method, and a flash memory management device that can prevent the occurrence of replacement and extend the life of the flash memory.

DISCLOSURE OF THE INVENTION.

In order to solve the above-mentioned problems and achieve the object, the present invention provides a flash memory in response to a request from a data management program for managing data stored in a flash memory. A flash memory management program for writing and reading data to and from a flash memory, comprising: a management procedure for managing, as block management information, the number of times of erasure of a physical block, which is an erasing unit of the flash memory, and update attributes of data. And a storage block acquisition procedure for acquiring a free physical block for storing data based on the number of erasures of the physical block managed as the block management information by the management procedure and an update attribute of the data. And

The present invention also relates to a flash memory management method for writing and reading data to and from the flash memory in response to a request from a data management program for managing data stored in the flash memory. A management step of managing the number of erasures of a physical block, which is a unit of memory erasure, and an update attribute of data, as block management information; and the number of erasures of a physical block, which is managed as block management information by the management step, and an attribute of data update. And a storage block acquisition step of acquiring an empty physical block for storing data based on the storage block.

Further, the present invention is a flash memory management device that writes and reads data to and from the flash memory in response to a request from a data management program that manages data stored in the flash memory, Management means for managing, as block management information, the number of erasures of physical blocks, which are units of memory erasure, and data update attributes; and the number of erasures of physical blocks and data update attributes managed as block management information by the management means. And a storage block acquisition means for acquiring an empty physical block for storing data based on the data.

According to this invention, the number of erasures of the physical block, which is the unit of erasure of the flash memory, and the update attribute of the data are managed as block management information, and the number of erasures of the physical block and the update attribute of the data, which are managed as the block management information, Based on this, a free physical block for storing data is acquired, so the number of erasures of the physical block in the flash memory is equalized, and the life of the flash memory is thereby reduced. You can extend your life. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram for explaining a flash memory file update process according to an embodiment of the present invention, and FIG. 2 shows a configuration of a flash memory management device according to an embodiment of the present invention. FIG. 3 is a functional block diagram. FIG. 3 is a diagram showing an example of the file management information and block management information shown in FIG. 2. FIG. 4 is a diagram showing the processing of the file update routine shown in FIG. FIG. 5 is a flowchart showing the procedure of a new file creation routine when the update attribute of a file to be created is “updatable”, and FIG. FIG. 7 is a flowchart showing a processing procedure of a new file creation routine when the update attribute of a file to be created is “updatable”. FIG. 7 is a block data movement routine shown in FIG. FIG. 8 is a flowchart showing a processing procedure of a block reallocation routine shown in FIG. 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a flash memory management program according to the present invention will be described with reference to the accompanying drawings.

Preferred embodiments of the flash memory management method and the flash memory management device will be described in detail. In the present embodiment, a description will be given mainly of a case where the present invention is applied to a flash memory file.

First, a flash memory file update process according to the embodiment of the present invention will be described. FIG. 1 is an explanatory diagram for explaining a flash memory file update process according to an embodiment of the present invention. FIG. 2A shows an example of updating the physical block of the flash memory when updating the flash memory file. Here, the physical block is a unit of erasing data in the flash memory, and its size is, for example, 16 KB. In this example, data 1 to data 4 are stored in physical block 1. FIG. 2B shows an example of block management information (information for managing physical blocks and the like) before and after updating the flash memory file. In this example, at the stage before the update of the flash memory file, the physical block 1 stores data whose update attribute is “updatable”, and its erase count is 200.

Here, the update attribute is information indicating whether or not a file whose data is stored in the physical block is updatable. If the file is updatable, the update attribute becomes “updatable”. If is not updatable, the update attribute is “updatable”. Similarly, the physical block 4 stores data whose update attribute is “updatable”, and its erase count is 500. The other physical blocks, physical block 2, physical block 3, and physical block 5, are unused, and the erase counts are 300, 100, and 400, respectively.

Then, when the update of the data 3 stored in the physical block 1 shown in FIG. 7A occurs, the data in the flash memory cannot be updated directly. Read into work buffer in RAM area. Then, change data 3 to data 3 'in the work buffer, and then write to another free block.

At this time, which empty block is used is determined by the number of erasures of each physical block and the update attribute of the data to be written as shown in FIG. In other words, when writing data whose update attribute is “updatable”, select an empty block with the least number of erasures, and when writing data whose update attribute is “updatable”, write the least erasable number. Select a free block that has more.

In this example, since the file is updated, the update attribute of the data to be written is “updatable”. Therefore, the number of erasures from the three free blocks of physical block 2, physical block 3, and physical block 5 is reduced. Select the least physical block 3 and write the data in the work buffer. If a new non-updatable file is created and data is written, the physical block 5 with the largest number of erasures will be selected. In addition, the update attribute of the physical block 3 is set to “updatable”. Finally, physical block 1 has all data erased and becomes an empty block, the number of erases increases by 1, and it changes from 200 to 201. Then, the block management information is updated as shown in FIG.

Thus, in the present embodiment, when writing data to an empty block, if the data to be written is updatable, the physical block is likely to be rewritten in the future, so an empty block with a small number of erases is selected. If the data to be written cannot be updated, the physical block will not be rewritten in the future, so an empty block with a large number of erasures is selected.Therefore, the number of erasures of the physical blocks in the flash memory is equalized. Therefore, the life of the flash memory can be extended. Next, a configuration of a flash memory management device according to an embodiment of the present invention will be described. FIG. 2 is a functional block diagram showing a configuration of a flash memory management device according to an embodiment of the present invention. As shown in the figure, the flash memory management device has a microprocessor 100, a program memory 200, a data area 300, and a flash memory 400.

The microprocessor 100 is a processing unit that controls the entire flash memory management device. More specifically, the flash memory 400 is managed by executing a program stored in the program memory 200.

The program memory 200 is a ROM or a RAM for storing a program. If the program memory 200 is a RAM, the program is read from the flash memory 400 when the flash memory management device is started. Is loaded into the program memory 200 and executed.

The data area 300 is a RAM for reading and storing the management information of the flash memory 400 from the management information storage area 410 when executing a program, and is an area for storing the operation results of the program. Also used as a buffer. The flash memory 400 is a storage unit for storing file data and the like, and has a management information storage area 410 for storing management information.

Next, a program included in the program memory 200 will be described. This The program memory 200 has a user program 210, a file management program 220, and a flash memory driver 230.

The user program 210 is any application program that uses the flash memory 400 via the file management program 220. The file management program 222 is a program for managing files stored in the flash memory 400. The file management program 220 may be provided as a part of the operating system (OS). The flash memory driver 230 is a program that writes and reads data to and from the flash memory 400 based on a request from the file management program 220. .

Next, information stored in the data area 300 will be described in detail. This data area 300 stores file management information 310 and block management information 320. The file management information 310 is information about a file, and the block management information 320 is information about a physical block and the like.

FIG. 3 is a diagram showing an example of the file management information 310 and the block management information 320 shown in FIG. As shown in the figure, the file management information 310 includes a file name indicating a file name, a start address indicating a storage start position of the file in the flash memory 400, a size indicating a file size, and a file. This is information in which an update attribute indicating whether or not the file can be updated is managed for each file.

For example, a file with the file name a.txt indicates that the storage start position in the flash memory 400 is 0x2000, the size is 0x100, and whether or not the file can be updated is "not updatable". However, the b. Txt file indicates that the storage start position in the flash memory 400 is OxaOOO, the size is 0x100, and the update availability is “updatable”. Here, Ox indicates a hexadecimal number. The start address is a logical address. By separating the start address from the physical address of the flash memory 400, even if the physical block that stores data is changed, the file can be stored without being affected by the change. Start position can be managed. The block management information 320 is information managing the logical address management information 321 and the physical block management information 322. The logical address management information 3 211 divides the logical space of the flash memory 400 defined by the logical address into logical blocks of a certain size, and starts logical address and logical address indicating the first logical address of the logical block. Information that manages, for each logical block, the size that indicates the size of the block, the physical block number that indicates the number of the physical block corresponding to the logical block, and the update attribute that indicates whether the file that stores data in the logical block can be updated. It is. This update attribute is the update attribute of the corresponding physical block. In other words, if this update attribute is “updatable”, the corresponding physical block is an updatable physical block (hereinafter referred to as “updatable block”). If this update attribute is “updatable”, the corresponding physical block is These physical blocks are non-updatable physical blocks (hereinafter referred to as “non-updatable blocks”). .

For example, a logical block whose starting logical address is 0x0000 has a size of 0x4000, the number of a physical block that actually stores the data is 12 and this physical block 12 is a non-updatable block. The logical block whose start logical address is 0x4000 has a size of 0x4000, indicating that the logical block is empty. Also, the logical block whose starting logical address is 0x8000 has a size of .0x4000, and the physical block number that actually stores the data is 14, and this physical block 14 is an updatable block The logical block whose start logical address is OxcOOO has a size of 0x4000, indicating that the logical block is empty.

Physical block management information 3 2 2 manages, for each physical block, the number indicating the physical block number, the usage status indicating the status of writing data to the physical block, and the erase count indicating the number of physical block erases so far. Information. For example, Physical Block 11, Physical Block 13 and Physical Block 15 are empty, indicating that the erase counts so far are 100, 500, and 200, respectively. . Also, physical blocks 12 and 14 have already been written with data. The number of erasures up to is respectively;

The file management information 310 and the block management information 320 are stored in the management information storage area 410 of the flash memory 400, and the data area is used when the flash memory 400 is used. Read into 300. When the flash memory 400 is updated, its contents are changed, and when the use of the flash memory 400 is finished, the change result is stored in the management information storage area 410.

Next, the flash memory driver 230 shown in FIG. 2 will be described in detail. The flash memory driver 230 has a file update routine 231, a new file creation routine 232, a block data movement routine 233, and a block reallocation routine 2324.

The file update ff routine 231 is a program for updating file data based on a request from the file management program 220. The file update / latin 23 reads data from the physical block storing the data to be updated into the data area 300, updates this data, and writes it to a new physical block. At this time, since the data to be written can be updated, the empty block acquisition processing acquires the empty block with the least number of erases.

The new file creation routine 232 is a program for writing new data to a physical block based on a request from the file management program 220. The new file creation routine 2 32 selects an empty block based on the attribute of the file to be created in the empty block acquisition process.

That is, if the update attribute of the file is “updatable”, an empty block with the largest number of erasures is acquired, and if the update attribute of the file is “updatable”, an empty block with the smallest number of erasures is acquired. In this way, by selecting an empty block based on the update attribute of a file to be created, the number of erasures of a physical block can be equalized, and the life of the flash memory 400 can be extended.

The block data movement routine 2 33 is a program that starts processing when an empty block occurs. This block data movement routine 2 3 3 Whether the number of erasures of the empty block with the smallest number of erasures exceeds the specified value or whether the number of erasures of the empty block with the largest number of erasures among the vacant blocks exceeds the specified value If the value exceeds the predetermined value, and if there is a non-updatable block in the non-updatable block and the number of erasures of the non-updatable block is less than the number of erasures of a free block, the data of the non-updatable block Is moved to an empty block where the number of deletions is large.

In this way, the number of erasures of the empty block with the smallest number of erasures among the empty blocks exceeds a predetermined value, or the number of erasures of the empty block with the largest number of erasures among the empty blocks is If the value exceeds the predetermined value, if there is a non-updatable block in the non-updatable block and the number of erasures of the non-updatable block is smaller than the number of erasures of an empty block, the data of the non-updatable block is deleted. By moving to an empty block with a large number of erasures, data that is not updated is prevented from occupying a physical block with a small number of erasures in the flash memory 400, and the number of erasures of the physical block is equalized. The life of 400 can be extended.

In addition, even if the number of times of erasure is large, the non-updatable block does not move its data to another physical block, so that the efficiency is not reduced due to unnecessary data exchange and the flash memory 400 Life can be extended.

The block reallocation routine 234 is a program that reallocates physical block data based on a user request. Specifically, the physical blocks are sorted as non-updatable blocks, updatable blocks, and empty blocks in order from the block with the largest number of erases.

In this way, by reallocating the data of the physical block based on the user's request, the number of erasures can be equalized and the life of the flash memory 400 can be extended.

Next, the processing of the file update routine 2 31 shown in FIG. 2 will be described. FIG. 4 is a flowchart showing the processing procedure of the file update routine 231, shown in FIG. It is a chart. As shown in the figure, the file update routine 2 31 obtains the physical block number storing the data of the file to be updated from the logical address of the file to be updated and the logical address management information 3 21. In step S 4 0 1), the data of the physical block number is read into the data area 3 0 0 (step S 4 0 2) ₀

Then, from the logical address of the file to be updated and the logical address management information 321, the address of the data in the corresponding physical block is calculated, and the data of the physical block read into the data area 300 is calculated based on this address. Change (step S403). Here, since the update attribute of the file is “updatable”, an empty block having the least number of erasures is obtained from the empty blocks (step S404), and the updated data is stored in the empty block. Write (step S405). Then, the logical block management information, the physical block number for the file logical address of 321, is updated, and the physical block storing the data before the update is erased to be a free block (step S407). ).

Next, the processing of the new file creation routine 232 when the update attribute of the file to be created is “updatable” will be described. FIG. 5 is a flowchart showing the processing procedure of the new file creation routine 232 when the update attribute of the file to be created is “updatable”.

As shown in the figure, this new file creation routine 2 32 has a free area large enough to write the file to be created in the existing non-updatable block when creating a non-updatable file. It is determined whether there is a block that cannot be updated (step S501). If there is a non-updatable block having a free area large enough to write a file, the logical address to which data is written using the logical address management information 3 21 from the address of the free area of the non-updatable block Is calculated (step S503), and the flow advances to step S506. On the other hand, if there is no non-updatable block having a free area large enough to write the file, the update attribute of the file is “updatable”, and the empty block with the largest number of erasures is obtained (step S). 5 0 2), an empty logical block is obtained from the file management information 3 10 and the block management information 3 2 0 (step S 5 0 4), and an empty block from which the physical block number of the obtained logical block is obtained. And the update attribute is set to “updating impossible” (Step S505).

Then, a new file name, start address, size, and update attribute are added to the file management information 310 (step S506), and data is written to the physical block address corresponding to the acquired logical address (step S506). S507).

Next, the processing of the new file creation routine 232 when the update attribute of the file to be created is “updatable” will be described. FIG. 6 is a flowchart showing the processing procedure of the new file creation routine 232 when the update attribute of the file to be created is “updatable”.

As shown in the figure, when creating a file that can be updated, the routine for creating a new file 2 32 has a free area large enough to write the file to be created in an existing updatable block. It is determined whether or not there is an updatable block (step S601). If there is an updatable block having a free area large enough to write the file, the logical address to which data is written is calculated from the address of the free area of the updatable block using the logical address management information 3 2 1. Then (step S603), the process proceeds to step S606. On the other hand, if there is no updatable block having a free area large enough to write the file, the update attribute of the file is “updatable J”, and the free block with the least number of erasures is acquired (step S 6 0 2), obtains a free logical block from the file management information 3 10 and the block management information 3 2 0 (step S 6 04), and obtains the physical block number of the obtained logical block. The number is set as an update attribute, and the update attribute is set to “updatable” (step S605).

Then, a new file name, start address, size, and update attribute are added to the file management information 310 (step S606), and the data is written to the physical block address corresponding to the acquired logical address ( Step S607). Next, the processing of the block data movement routine 233 shown in FIG. 2 will be described. FIG. 7 is a flowchart showing a processing procedure of the block data movement routine 233 shown in FIG.

As shown in the figure, the block data movement routine 233 determines whether the number of erasures of the empty block having the smallest number of erasures among the empty blocks exceeds a predetermined value, or the number of erasures within the empty block. It is determined whether the number of erasures of the most vacant block exceeds a predetermined value (step S701), and if it does not exceed the predetermined value, the process is terminated without doing anything.

On the other hand, if the value exceeds the predetermined value, it is further determined whether there is a non-updatable block in the non-updatable block, the number of erasures of the non-updatable block being less than the number of erasures of an empty block. If there is no non-updatable block, the process ends without doing anything. If there is a non-updatable block, the data of the non-updatable block is moved to an empty block having a large number of deletions (step S703), and the physical block is erased to become an empty block (step S700). Four ) .

Next, the processing of the block reallocation routine 234 shown in FIG. 2 will be described. FIG. 8 is a flowchart showing the processing of the block reallocation routine 234 shown in FIG. As shown in the figure, the block re-allocation routine 234 selects one non-updatable block (step S801), and determines the number of erasures and the number of erasures in the empty block and the updatable block. The most frequent value is compared (step S802).

If the number of erasures of the non-updatable block is small, the data of the non-updatable block and the physical block with the largest number of erasures among the empty blocks and the updatable blocks are exchanged (step S803). Conversely, if the number of erasures of the non-updatable block is equal to or more than the maximum value of the number of erasures of the empty block and the updatable block, the process proceeds to the next step without doing anything about the non-updatable block.

Then, it is determined whether all non-updatable blocks have been investigated (step S 8 0 4) If there is a non-updatable block that has not been checked, the above processing is repeated for the next non-updatable block. On the other hand, when all the non-updatable blocks have been prepared, the process proceeds to the next step, that is, the processing of the updatable blocks.

In the next step, one updatable block is selected (step S805), and the number of erasures of the updatable block is compared with the maximum value of the number of erasures of the empty block (S806). If the number of erasures of the updatable block is small, the data of the updatable block and the data of the physical block having the largest number of erasures in the empty block are exchanged (step S807). Conversely, if the number of erasures of this updatable block is equal to or greater than the maximum value of the number of erasures of the free block, the process proceeds to the next step without doing anything with this updatable block.

Then, it is determined whether or not all updatable blocks have been examined (step S808). If there is an updatable block that has not been examined, the above processing is repeated for the next updatable block. On the other hand, when all the updatable blocks have been adjusted, non-updatable blocks, updatable blocks, and empty blocks are arranged in order from the block with the largest number of erases, and the reallocation of the physical blocks is completed.

In this embodiment, when writing data to an empty block, if the data to be written can be updated, the physical block is likely to be rewritten in the future, so an empty block with a small number of erases is selected, and the data to be written is updated. If it is not possible, the physical block will not be rewritten in the future, so an empty block with a large number of erases is selected.Therefore, the number of erases of the physical block in the flash memory 400 is equalized, and the flash memory 4 The life of 00 can be extended. Also, the number of erasures of an empty block with the least number of erasures among the empty blocks exceeds a predetermined value, or an empty block with the largest number of erasures among the empty blocks If the number of block erasures exceeds a predetermined value, the data in the non-updatable block with a small number of erasures is moved to a vacant block with a large number of erasures. It is possible to prevent the physical block from being continuously occupied by the small number of erases of 00, and to equalize the number of erases of the physical block, thereby extending the life of the flash memory 400.

In addition, even if the number of erasures is large, the non-updatable block does not transfer the data to another physical block, so that the efficiency is not reduced due to the exchange of unnecessary data and the flash memory 400 Life can be extended.

In addition, by reallocating the data of the physical block based on the user's request, the number of erasures can be equalized, and the life of the flash memory 400 can be extended.

As described above, according to the present invention, the number of erasures of a physical block, which is an erasing unit of a flash memory, and the update attribute of data are managed as block management information, and the number of erasures of a physical block managed as block management information is managed. In addition, since a free block for storing data is acquired based on the data update genus, the number of erasures of the physical block in the flash memory can be equalized, thereby extending the life of the flash memory. It has the effect of being able to do it. Industrial applicability

As described above, the flash memory management program, the flash memory management method, and the flash memory management device according to the present invention are suitable for flash memory files that handle a large amount of data that cannot be updated.

Claims

The scope of the claims

1. A flash memory management program that writes and reads data to and from the flash memory in response to a request from a data management program that manages data stored in the flash memory,

A management procedure for managing, as block management information, the number of erasures of a physical block, which is an erasing unit of the flash memory, and an update attribute of data;

A storage block acquisition procedure for acquiring a free physical block for storing data based on the number of times of erasure of a physical block managed as block management information by the management procedure, based on an update attribute of data;

A flash memory management program, characterized by executing:

2. An empty block erase count monitoring procedure for monitoring the number of empty physical block erases, and a physical block erase count and an empty physical block whose data update attribute cannot be updated based on the monitoring result of the empty block erase count monitoring procedure. Based on the comparison result of the erase count comparison procedure for comparing the block erase count, and the erase count comparison procedure! Moving the data stored in the physical block whose update attribute is not updatable to a free physical block having a large number of erasures. The flash memory management program according to item 1.

3. The flash memory management according to claim 2, wherein the monitoring step of the number of times of erasing the empty block monitors whether the number of erasures of a free physical block having the least number of erasures exceeds a predetermined value. :

4. The flash according to claim 2, wherein the step of monitoring the number of erasures of the empty block monitors whether the number of erasures of an empty physical block having the largest number of erasures exceeds a predetermined value. Memory management program.

5. The storage block acquisition procedure acquires a free physical block with a large number of erasures when the data update attribute is not updatable, and a small number of erasures when the data update attribute is updatable. 5. The flash memory management program according to claim 1, wherein a free physical block is acquired.

6. The flash memory management program according to claim 5, further comprising a block reallocation procedure for reallocation of a physical block storing data based on a user's request.

7. The block re-allocation method is as follows: the physical block whose data update attribute cannot be updated, the physical block whose data update attribute can be updated, and the empty physical block. 7. The flash memory management program according to claim 6, wherein reallocation of a physical block is performed.

8. A flash memory management method for writing and reading data to and from the flash memory in response to a request from a data management program for managing data stored in the flash memory,

A management step of managing, as block management information, the number of erasures of a physical block as an erasing unit of the flash memory and an update attribute of data,

A storage block acquisition step of acquiring an empty physical block for storing data based on the update count of the physical block managed as the block management information by the management step,

A flash memory management method characterized by including:

9. Empty block erase count monitoring step to monitor the erase count of empty physical blocks An erase count comparing step of comparing the erase count of a physical block whose data update attribute cannot be updated with the erase count of an empty physical block based on the monitoring result of the empty block erase count monitoring step; A non-updatable data transfer step of moving data stored in a physical block whose update attribute of the data is not updatable to a free physical block having a large number of erasures based on a comparison result of the steps. The flash memory management method according to claim 8, wherein the flash memory management method is characterized in that:

10. The empty block erase count monitoring step monitors whether the erase count of an empty physical block having the least erase count is greater than a predetermined value. Flash memory management method.

11. The flash memory according to claim 9, wherein said free block erase count monitoring step monitors whether the erase count of a free physical block having the largest erase count exceeds a predetermined value. Management method.

1 2. In the storage block acquisition step, when the data update attribute is not updatable, an empty physical block with a large number of erases is acquired, and when the data update attribute is updatable, the storage block The flash memory management method according to claim 8, wherein a small free physical block is acquired.

13. The flash memory management method according to claim 12, further comprising a block reassignment step of reassigning a physical block storing data based on a user's request.

1 4. In the block reassignment step, the number of times of erasure is large, the physical block whose data stored sequentially from the physical block cannot be updated, and the data 14. The flash memory management method according to claim 13, wherein a physical block is reallocated as an updatable physical block or a free physical block.

15. A flash memory management device that writes and reads data to and from the flash memory in response to a request from a data management program that manages data stored in the flash memory,

Management means for managing, as block management information, the number of erasures of a physical block and the update attribute of data, which are units of erasure of the flash memory,

Storage block acquisition means for acquiring an empty physical block for storing data based on the number of times of erasure of a physical block managed by the management means as block management information and an update attribute of data;

A flash memory management device comprising:

1 6. An empty block erase count monitoring means for monitoring the erase count of an empty physical block, and a physical block erase count for which the data update attribute is not updatable based on the monitoring result of the empty block erase count monitoring means. Means for comparing the number of erasures of an empty physical block; and a method for erasing data stored in a physical block in which the update attribute of the data cannot be updated based on the comparison result of the erasure number comparing means. 16. The flash memory management device according to claim 15, further comprising: a non-updatable data moving unit that moves to a physical block when the data is transferred.

17. The empty block erase count monitoring means monitors whether the erase count of an empty physical block having the smallest erase count exceeds a predetermined value. Flash memory management device.

1 8. The empty block erase count monitoring means determines that the erase count is the highest 17. The flash memory management device according to claim 16, wherein it is monitored whether the number of block erasures exceeds a predetermined value.

The storage block obtaining means obtains a free physical block having a large number of erasures when the data update attribute is not updatable, and obtains the erase block count when the data update attribute is updatable. The flash memory management device according to claim 15, wherein a physical block having a small amount of free space is acquired.

20. The flash memory management device according to claim 19, further comprising a block reallocation unit that reallocates a physical block storing data based on a user's request.

21. The block re-assignment means includes a physical block whose data update attribute is not updateable, a physical block whose data update attribute can be updated, and a free physical block, which are stored in order from the physical block with the largest number of erases. 20. The flash memory management according to claim 20, wherein reallocation of physical blocks is performed.