JP3503448B2 - Flash type memory and its management device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash type memory and a management apparatus therefor, and more particularly to improvement of an efficient management method for a flash type memory.

[0002]

BACKGROUND OF THE INVENTION Electrically erasable programmable read only memories (EEPROMs), which generally include flash type floating gate transistors, are now readily available on the market. These so-called flash memories are nonvolatile memories similar in function and performance to EPROM memories, and further have a function of enabling in-circuit programmable operation to erase blocks divided in the memory. In a flash memory, rewriting is performed by previously erasing a previously written area of the memory.

In a typical computer system, a program of an operating system (hereinafter, simply referred to as "OS") manages data in a data storage device of the system. The attributes (attributes) of the data storage device that are necessary and sufficient to achieve compatibility with the OS program are obtained from any location of the data storage device.
That is, data can be read and data can be written to it. However, in the case of the flash memory, in the area where the data has already been written, the data cannot be written unless the data in the area is erased. Therefore, the flash memory is not compatible with typical existing OS programs.

Focusing on such a point, software which enables the flash memory to be managed by an existing OS program has been proposed in the prior art.
In this prior art program, the flash memory is operated as a "write once, read multiple times" device or a "write multiple times, read multiple times" device. The former is a device that cannot reuse previously written memory locations and can be used as auxiliary or extended storage. In the latter, there is an auxiliary storage device (semiconductor file storage device) that enables the previously written memory area to be reused and has control to reduce the number of times of rewriting of the flash memory.

[0005]

However, the above background art has the following disadvantages. (1) According to the device seen in the prior art as described above, the execution program is operated on the extended storage device using the flash memory without having a control structure that reduces the number of rewrites. That is, when newly rewriting data in the flash memory, it is necessary to erase all blocks at once and then store the data.
Further, in the case of performing management such as sharing or occupation of a parallel execution program or data represented by multitask, multithread, multiprocess, a general MMU.
It is difficult to manage the number of times of rewriting and reduce the number of times of rewriting with the method of managing the flash memory for each block (page) by making full use of the (memory management unit).

(2) An auxiliary storage device (semiconductor storage device (semiconductor storage device) There is a file storage device). This is a method of storing the information (rewrite count table) in different memories in order to reduce the number of rewrites in the auxiliary storage device. However, in a program that operates on the flash memory without loading the execution program on the main memory, the method of simply storing the program on the same flash memory allows data that spans between blocks to be completely continuous without waste. It is difficult to enable a specific arrangement.

The present invention focuses on the above points,
The purpose thereof is to provide a program on the extended storage device without loading the execution program to the main storage device when the control structure is such that the number of times of rewriting of the flash memory is reduced on the extended storage device using the flash memory. Is to be able to execute. Another purpose is to use the same flash memory and have a control structure that reduces the number of times of rewriting as an auxiliary storage device, while using a memory management device even in an advanced program execution environment such as multiprocessing, multithreading, and multitasking. That is, it is possible to safely realize the management of the module of the execution program and the data file. Still another object is to provide a file management technique that enables a mixture of an extended storage device and an auxiliary storage device on the same flash memory.

[0008]

Means for Solving the Problems] flash memory of the present invention, the flash memory is first to be erased stored content in blocks, the second includes a third block, the first block, The block includes a header area for storing management information of the block and a storage area for storing a data file divided into blocks. The third block stores management information of the block in which the execution program file is stored. And a storage area for storing an execution program file divided into blocks, and the second block is adjacent to the third block.
Then, the execution program file executes the third block.
Exceeded the capacity of the storage area for storing program files
If the execution program file is divided into the third block
And a storage area for storing the stored subsequent data .

[0009]

Flash memory management apparatus of the present invention
Shall be assigns an execution program file for a plurality of the second and third blocks adjacent, comprising means for storing management information of the block to which they run the program file is assigned to the third block Is characterized by.

[0011]

[0012]

[0013]

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description and the accompanying drawings.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. In this embodiment, as shown in FIG. 1, for example, an expanded or auxiliary storage device including a processor 10, a flash memory 12 and a control device 14 thereof, an RA
It is applied to a computer system including an M (main memory) 16. In such a system, the same flash memory is used to coexist the data of the execution program module and the data file, and a data storage method for reducing the number of data rewrites as much as possible. It is intended to obtain a device for management / control.

First, in order to manage the execution program area and the data area, the management unit of the flash memory 12 is one block which is the minimum erase (erase) unit. Then, the execution program area and the data area cannot be mixed in the block which is the minimum unit. Each block has an execution program area or data area, and a header area having information for managing the block.

Here, it is declared that the block to be allocated to the data area has a data attribute in the header area of the block. Similarly, a block to be assigned to the execution program area is declared to have the attribute of the execution program in the header area of the block. However, for this execution program area,
One header area is not necessarily required for one block. That is, when it is desired to continuously secure a plurality of chained blocks as an execution program area, the number of reserved blocks is declared in the header area. by this,
The declared chained multiple blocks may not have header information. In other words, as the memory layout of the execution program, one header area secures the execution program area in a plurality of consecutive blocks. On the other hand, the data area is 1
It will be mixed with the header area in one block. Information about the corresponding block is added to this data area.

FIG. 2 shows an example of the basic structure of software in this embodiment. As shown in the figure, OS2
0 and socket interface with application software 22
As a face, a flash management manager 26 is provided in a portion corresponding to the so-called driver layer 24. The flash management manager 26 can be considered as the system driver of this embodiment. This flash management manager
The jar 26 manages block information and rereads data.
Control of read / write.

For example, as shown in FIG. 3A, block erasing can be performed in i-byte units and the number of blocks is n +.
It is assumed that there is one (1 hexadecimal number) flash memory. Each of these blocks will be called a physical block. Then, physical block numbers “0” to “n” are assigned to each physical block in order from the lowest address to the highest address. In the illustrated example, addresses are lower in the upper part of the figure and are physical block 0, physical block 1, physical block 2, ..., Physical block n.

Assuming that j bytes are reserved as a header area of information for managing each physical block, the size of the execution program area or data file area allocated to each physical block is i-j.
It becomes a byte. Then, in the storage area of the same block,
It is not allowed to mix the execution program area and the data file area. This state is shown in FIG. 3B. For example, in the uppermost physical block 0, a j-byte header area 30A and an i-j-byte storage area 30 are included.
B exists. In the next physical block 1, there is a header area 31A of j bytes and a storage area 31B of ij bytes. The same applies to the following physical blocks.

Next, an example of securing the execution program area will be described with reference to FIG. In FIG. 4A, eight consecutive physical blocks 0 to 7 are assigned as execution program areas, and the other physical blocks 8 to n are assigned to the data areas.
This is an example of allocation as a data file area. As described above, the execution program area secured in a plurality of continuous physical blocks is managed by one header area. On the other hand, the data file area is managed by the header area for each block even if it is secured in a plurality of continuous physical blocks. Therefore, in the example of FIG. 4A, the physical block header 3 of the execution program area 32 is
2A exists only in physical block 0, and physical blocks 1 to
It does not exist in 7. Then, as will be described later, the management information of the physical blocks 1 to 7 will be collected in the header area 32A of the physical block 0. On the other hand, although data file areas 38B to 3nB are secured in the physical blocks 8 to n, respectively, the header area 3 is provided in each block.
8A to 3nA exist and are managed for each block by these.

Next, in the example of FIG. 4B, the physical block 0
Is allocated as a data file area, and physical block 1
In this example, .about.A is allocated as the execution program area and thereafter is allocated as the data file area. Figure 4
In the example of [C], the physical blocks 0 to n-9 are assigned to the data file area, the physical blocks n-8 to n-3 are assigned to the execution program area, and the subsequent ones are assigned to the data file area. . In this way, the execution program areas that are continuously secured are managed by one header area. Further, there is no limitation on the number of physical blocks or fixed address arrangement. However, the data file area is managed for each block even if it is continuously secured.

In the example shown in FIG. 5, the execution program area is divided and arranged. First, in the example of FIG.
An execution program area (1) is allocated to the physical blocks 0 to 7, and a data file area is allocated to the physical block 8. Then, physical blocks 9 to F-
The execution program (2) is assigned to 1 and is reserved for the data file area after the physical block F. In this example as well, continuous execution program areas are managed by one header area.

In FIG. 5B, the physical block 0 is allocated for the data file area and the physical block 1 is allocated.
.About.8 are assigned to the execution program area (1).
The physical blocks 9 to n-9 are allocated for the data file area, and the subsequent areas are allocated as the execution program area (2). Figure 5
In [C], physical blocks 0 and 1 are allocated as data file areas, and physical blocks 2 to 4 are allocated to the execution program area (1). The subsequent physical blocks 5 to n-9 are allocated as data file areas, and the physical blocks n-8 to n-1.
Is allocated as the execution program area (2),
The last physical block n is assigned to the data file area. In these FIG. 5, two areas (1) and (2) are designated as the execution program areas. However, in this embodiment, it is possible to arrange the execution program area in a plurality of areas.

Next, the header area of the physical block will be described. The physical block header has an execution program area and a data file area. In order to determine these two types of areas, it is desirable that the headers have a common structure. Therefore, the structure of the common portion of the physical block header is assigned as follows, for example.

(1) Flag indicating status (valid / invalid / during transition / initialization completed) (2) Marker flag indicating execution program area / data file area (3) Number of continuous reserved block areas ( 4) Number of block erasures (5) Number indicating the block erasing order (erasure
(6) Block initialization time (7) Block area name

Of these, the flag (1) will be described first. Flash management manager 26 (see FIG. 2)
Reads the contents of each physical block header to understand how the flash memory is managed. Bit data in a memory cell of a flash memory has a relatively short processing time for changing a logical value from "1" to "0",
The change from “0” to “1” requires a block erase or erase once, which requires a long time. In other words, in order to rewrite 1-bit data, it is necessary to temporarily save the data in the block and write it back after the block erase, which is a long processing time.

Therefore, in reality, the state of the physical block is managed by using the flag indicating the state. That is, in order to reduce the overhead caused by the above-mentioned rewriting, the physical block in the physical block header is in a valid state, or is invalid state, initialization is completed state, or invalid state from valid state. A state such as a transition state to a different state is recognized for each physical block, and operations such as writing data, invalidating data, erasing the physical block, and initializing the physical block are performed. .

Next, the marker flag (2) is a flag indicating whether the corresponding physical block is allocated to the data file area or the execution program area. As a result, when specified in the execution program area, the number of blocks following the execution program is specified in the number of consecutive reserved blocks in (3). However, when it is specified in the data file area, the number of consecutive reserved blocks is set to 0.

Next, the number of times of erasing (block erase) each block is recorded as the number of times of erasing blocks in (4). When performing block erase, the previously recorded erase count is temporarily retained, and after the block erase is completed, the temporarily retained previous erase count is incremented by 1 and data is stored. Store.

Next, the number (5) indicating the erased order of the blocks is the same as the erased order of the physical blocks in the same order.
This is for determining whether or not the scan has been performed. If a physical block is block-erased and then another physical block has the same block erase count, the erase sequence number of the block having the same erase count is incremented by 1 and the block erased. -Store in the sequence number. That is, when a plurality of blocks having the same erase count exist, the maximum erase sequence number among them is incremented by 1 and stored in the erase sequence number in the corresponding block header.

Next, in (6) the time when the block is initialized, the time when the corresponding physical block is block erased is entered. It is not necessary in the case of a system that does not have a real-time clock.

Next, the block area name of (7) is a unique name assigned to the block in the execution program or the data file.

When allocating a new block, the above management information is used in order to manage all the blocks efficiently, that is, so that the number of erases is equalized in all blocks without being biased to a specific block. Used. First, when allocating a new physical block, the flash management manager 26 preferentially allocates a physical block having a small erase count. If there is a block with the same erase count, the one with the smallest erase sequence number is assigned. Youngest
The block of the sequence number has the oldest erased time. Also, in a system having a real-time clock, that clock is used instead of the erase sequence number. That is, when there is a block with the same erase count, the block having the oldest time in the physical blocks among them is assigned. In this way,
By using either the sequence number or the real-time clock, the block allocation can be made uniform even a little.

The location of the execution program is determined by executing the execution program data in the area after the physical block header.
This is done by arranging the data in the same way as in the ROM. This is because the part that depends on the OS 20 is large.
It will be dealt with by the conventional method.

On the other hand, the placement of the data file is performed by the flash management manager 26. As shown in FIG. 6A, the data file has a physical block header 4
The data is stored in the storage area 40B excluding the area of 0A. As a data storage structure, a logical data record in the data file is blocked and, as shown in FIG. 6B, a data record header 42A and a data record.
Data record 42B in the form of an attached D-Fuda 42C
Packet 42 of FIG. Blocking methods include fixed-length records, variable-length records, and spanned records.
In this embodiment, any method may be used. Since this blocking often depends on the OS 20 and application software 22, the flash management manager 26 determines and controls the blocking method on the system.

Further, the data record header 42A and the footer 42C are provided with a linear list structure.
The optimum use of the block area name differs depending on the data record method. When designing the system, as the block area name, partition name, data file name,
Try to assign the most suitable one, such as a directory name. The optimum block area name often depends on the method of data recording.

The logical data record 42B of the data file is the data record packet 42 as described above.
Is stored in the data file area 40B of the allocated physical block. This is shown in FIG. 6B, in which the data record packets (1) to (n) are i-
It is stored in the j-byte data file area 40B.
The flash management manager 26 carries out dual management of management of the data record packet 42 and management by the physical block 40B.

Next, the procedure for initializing the physical block will be described. If the flash memory is not initialized, the flash management manager 26 first initializes each physical block. When initialization is performed, all blocks are erased once, and the initialization completion flag, erase count (1 time), and erase are written in the block header of each physical block.
Stores information such as the sequence number or initialization time. Next, in order to normally store the execution program and the data file, the area of each physical block is declared (reserved). That is, a marker flag indicating an execution program area and a data file area, and information on the number of areas of continuous reserved blocks are stored. At this time, the area name of the block may be assigned. If the area name of the block is to be assigned later, the flash management manager 26 handles it.

Next, the procedure for storing the data file will be described. Turns on the physical block header valid flag
And then the blocked data record is
Data is sequentially stored in the data area. The data record is additionally written in the data area. However, if the data record is to be rewritten, it is largely overwritten to rewrite that portion due to the characteristics of the flash memory.

Therefore, in storing data from the old logical data record to the new logical data record, the old data record is invalidated and a new data record is additionally written. Do by the way. The invalid data record can be judged to be invalid by the flash management manager 26 by providing an invalid flag in the data record header. When all the data record packets in the data area of the physical block are invalid, the invalid flag in the physical block header is turned on, and the flash management manager 26 selects this physical block. Block erase can be performed. When the block erase is completed, the above block header is initialized.

Next, the procedure for storing the execution program will be described. When a plurality of blocks are initially secured as the execution program area, information such as a valid flag in the physical block header, a marker flag indicating the execution program area, and the number of reserved area blocks is stored. As a result, the ROMized data of the execution program is stored in the execution program area.

The above is operated as a system, and as the intermediate result, the number of rewriting of the data file area and the number of rewriting of the execution program area are compared. If there is a large number of openings, it is desirable to change the currently arranged area and perform defragmentation. Since the flash management manager 26 manages the respective areas, it can cope with the dynamic arrangement in the defragmentation operation, and there is no fear of causing a contradiction in the system. By performing these, efficient area arrangement can be realized. Further, as a result, it is possible to prolong the operation time and prolong the rewriting life (time, not the number of times) of the flash memory.
Depending on the flash memory, there are some chips that cannot perform other operations during the write (write) operation. In such a case, exclusive control is performed by a programming technique such as task and thread.

FIG. 7 shows a storage example of the physical block header in the flash memory. The example in FIG. 7A is a flash memory in which 64 Kbytes are used as an erase block unit, and the system has n + 1 blocks. As shown in FIG. 7B, 256 bytes are allocated to the head of each physical block as a header area which is management information of each physical block. As described above, in the case of the data file, the physical block header is always attached to the corresponding physical block. However, this does not apply to the case of the execution program file. Hereinafter, examples of this embodiment will be described.

(1) Example 1 Example 1 is an example using a block sequence number. In the file management device of this example, as shown in FIG. 8A, block erasure can be performed in units of 64 Kbytes.
M × 8 bit flash memory is used. Figure 8
As shown in [A], each block has "0" to "1F"
Number in order. Assuming that the execution program area is secured as a continuous area in such a flash memory as shown in FIG. 5A, it becomes as shown in FIG. 8B. Naturally, the physical blocks 1 to 7 designated in the execution program area (1) do not have a physical block header. Similarly, the physical blocks 10 to E designated as areas in the execution program (2) have no physical block header.

Therefore, in this embodiment, as shown in FIG. 9, the first to 18th bytes have a common data structure. As a result, if this common part is scanned by the flash management manager 26, the entire structure can be grasped. Then, the contents allocated to the execution program area or the data file area may be added from the next 19th byte.

The contents of the common part will be described in order.
At the byte, as shown in FIG. 10A, there are flags of valid / during transition / invalid, initialization completion state, and reservation. Of these, the valid / transitional / invalid flag indicates whether this block area is in a valid state, in a transitional state (transition period) from valid to invalid, or in a completely invalidated state. The initialization completion state flag indicates that the initialization (format) of the block header is completed after the block is erased. The reserved flag is a reserve flag used for expanding the system. An example of actual bit allocation is shown in Table 1 [A].

[0048]

[Table 1]

Next, a block erase procedure will be described with reference to FIG. Flash management manager 2
When the block erase command is issued by the judgment of 6 (50 in FIG. 10 [B]), the number of erases of the old block header is temporarily stored as the next state (52), and the block erase of this block is executed. (54). Immediately after performing the block erase, the data values of the storage areas of the erased blocks are all FFh (5
6). Immediately thereafter, the flash management manager 26 performs an initialization (format) operation (58) to set bit 4 to 0, and the data value of this storage area transits from FFh to EFh (60).

After that, a value obtained by adding 1 to the erase count temporarily stored before the erase is written to the header of this block to initialize the physical block. Then, if it is assumed that the flash management manager 26 newly allocates a request to use this block (62),
Write 0 to bit 7 and the value of the data in this area is E
A transition is made from Fh to 6Fh (64). Further, if the flash management manager 26 recognizes the invalid request of this block (66), 0 is written in the bit 6 and the data value of this area transits from 6Fh to 2Fh (68).

When performing defragmentation, due to the function of the flash management manager 26, physical blocks have transitional states such as copy source, copy destination, and move. To change from the valid state in the physical block as the data file area to the transitioning state (7
0), bit 5 is set to 0, and the data value of this area is 6
The transition may be made from Fh to 4Fh (72). The existence of this transitional state means that the time required for the transition is not short, the operation is unstable due to the consumption of the battery,
This is to enhance safety when the card type flash memory is removed. That is, the present invention is configured to manage the state of this transition stage, minimize the loss of data due to a failure or accident, and restore the data.

Next, the second byte of the common part shown in FIG. 9 will be described. As shown in FIG. 9, there are flags for the program / data and the number of consecutive reserved block areas in the second byte, and they are as shown in FIG. 10 [C] and Table 1 [C]. Of these, the program / data marker flag is a flag that determines which of the execution program and the data file is assigned to the block. When this marker flag is 0, this block is designated in the execution program area.

In the flag of the number of continuous reserved block areas, the number of remaining blocks designated in the execution program area is expressed in hexadecimal. However, this marker flag is 1
When this physical block is allocated as a data file area, the number of continuous reserved blocks is 000000.
Write 0b.

Next, the 3rd to 5th bytes in FIG.
As shown in [D], the erase count of the block is expressed in hexadecimal. The 3rd byte is the lower digit of the count, 4
Data is stored in the byte as the middle digit of the count and in the fifth byte as the upper digit of the count. Therefore, FFFFFFh times is the maximum numerical value of block continuity. At this maximum value, no further increment is performed.

Next, regarding the 6th byte in FIG. 9, this is prepared for the flash management manager 26 to optimally allocate a physical block when the number of erases of each physical block is the same. This is the erase sequence number described above. This erase sequence number records the order in which the physical blocks were initialized when the number of times of erasing the physical block was the same as that of other physical blocks. As the flow of erasing sequence number allocation, first, if there is no same erase count in the corresponding physical block and erase count in other blocks,
The erase sequence number of the corresponding physical block is 0.
It becomes x00.

If another block has the same erase count, the largest erase sequence number is detected, and the erase sequence number of the corresponding block is detected. The value obtained by incrementing the value of the Kens number by 1 is recorded. An erase sequence number is assigned by such an algorithm. The erase sequence number is used as a judgment factor when the flash management manager 26 allocates a physical block.

Next, in the 7th to 18th bytes of FIG. 9, the area name of the corresponding block is recorded. In the case of an execution program file, if it is used as a partition name or directory name, system operation becomes easy.
Further, in the case of a data file, it is conceivable to handle the block area name optimally by the data record method. For example, in the case where the data recording method double manages files such as fixed length, variable length records and spanned records, the partition name and directory name are suitable. However, in the case of unified management of files with fixed length or variable length records, it is desirable to handle them as data file names. In this embodiment, the block area name is in the 8.3 format and an expression method such as MS-DOS is used.

A flash file management system is realized by using the physical block header having the above structure. The flash management manager 26 uses the OS 20 and application.
The read / write of the execution program and the data file is controlled by the request of the application software 22 and the like.
First, when writing, a characteristic of the flash memory is a write delay. For this reason, in order to reduce the over head and to perform writing efficiently, a method of newly writing to another data file area is adopted. In order to execute this method, the old data before rewriting and the new data after rewriting are logically changed, but the old data is physically invalid and the new data is physically changed. Will be added.

That is, although the old data and the new data physically coexist, they are logically deleted by writing an invalid flag in the old data. When the flash file system repeats such an operation, many logical invalid data exist. In some cases,
There is even a risk of running out of new data file areas.
To avoid this, the flash management manager 2
6 periodically detects invalidation of data and performs defragmentation operation to efficiently secure a data file area.

The flash management manager 26 assigns a physical block as a data file area. At this time, OS20 and application software 2
Although the data file area is provided by the request of No. 2, the algorithm of the present embodiment preferentially allocates the physical block to the physical block having the smaller erase count. Also, when performing a defragmentation operation, the data record packet is invalidated preferentially for a block with a small number of erases, and the entire data file area of that physical block is invalidated. The number of times the blocks are used can be made uniform. In order to efficiently equalize the number of times physical blocks are used among these, the physical blocks and block erases to be allocated are managed by giving priority to the youngest erase sequence numbers.

As the flash file system is operated, as a result, the number of erasures in the execution program area and the data file area will be significantly different. Then, when the number of erasures is increased to some extent, the flash management manager 26 replaces the physical block used in the execution program area with the physical block used in the data file area, thereby the flash file system. The operating life of is extended.

In the case of reading, the flash management manager
Jar 26 requests the flash memory to be read, and after confirming the permission, the blocked data record
This is possible by treating the packet as a logical data record. In the case of writing, the flash management manager 26 is requested to write to the flash memory, and after confirming the permission, the logical data record is blocked and the data record packet is designated and designated. Store in area. The rewriting of data is realized by physically invalidating the data record packet and newly writing it. However, the memory area is physically reduced. The method of blocking these data is as described above and is realized by the background art.

When all the data is invalidated in the data file area of the physical block, the invalidation flag of the physical block header is turned on, which means that the entire physical block is invalidated. Then, the flash management manager 26 detects this, erases the block, and starts the initialization operation. Also, by the defragmentation operation, the transition flag of the physical block header to which the copy source data file belongs is turned ON.
To When all the necessary data has been copied, the invalid flag of the physical block header is turned on,
The block erase / initialization operation described above is performed. When there is an abnormal state due to some cause from the ON of the transition flag to the ON of the invalid flag, and when the system is restarted, monitor and analyze these state flags to stop from which state Alternatively, it is possible to detect whether an abnormality has occurred. It will also be a valuable source of information for repairing and restoring the system.

The flash management manager 26 monitors and manages the state of each physical block. In response to a request from the OS 20 or the application software 22, a corresponding physical block is assigned, and monitoring and management of the state of valid → (during transition) → invalid → initialization are executed. And when you operate the flash file system,
Changes in the state of each physical block include initialization → valid, valid → invalid, valid → transitioning, moving → invalid, invalid → initialization,
Initialization → invalidation, etc.

[Initialization → Valid] is set to the valid state by turning on the valid flag when the physical block is allocated from the initialized state as a data file area or the like.

[Valid → Invalid] indicates that the physical block is valid as a data file and at least one logically valid data exists in the data file area, and The data becomes logically invalid data, and the flash management manager 26 subsequently turns on the invalid flag of this physical block to invalidate the physical block.

[Effective → During transition] is a physical copy source when at least one existing logically valid data record packet is copied to a data file area of a different physical block. The transition flag is turned ON for the block. In this state, the data record packet has been copied.

[Transition → Invalid] indicates that the above-mentioned state during transition has ended and the physical block has become invalid. That is, the copying of the data record packet is completed, and the flash management manager 26 turns on the invalid flag.

In [Invalid → Initialize], when the physical block is block-erased from the invalid state and the initialization of the physical block header is completed, the flash management manager 26 sets the initialization flag. Turn it on. At this time, the initialization of the physical block header is completed, and the physical file header becomes usable as a data file area.

[Initialization → Invalid] indicates a state in which the physical block is invalidated after the physical block is initialized. This may exist as a state, but should not be overused by the system.

The flash management manager 26 manages / monitors the state of each physical block, and after exiting from the abnormal state due to some cause, sets the valid / invalid / during transition / initialization flag to the data before the abnormal state. It will be used as an information source for restoring and restoring data. In other words, by considering these change states, it is possible to detect from which state the abnormality has occurred when the system is stopped or the system in which the abnormality has occurred is repaired or the data record packet is restored.

(2) Second Embodiment This second embodiment is a method of recording the initialized time instead of the erase sequence number of the first embodiment. That is, as shown in the structure of the block header in FIG.
Record the year / month / day / hour / minute / second from the 9th byte to the 21st byte. The erase sequence number of the first embodiment refers to the initialized order when the same erase count is used. However, in the second embodiment, in the algorithm for equalizing the use count of blocks, all physical blocks In order to improve the number of times of use as efficiently as possible, the physical blocks and block erases to be allocated are managed by giving priority to the oldest time when the number of times of erasure is the same.

(3) Third Embodiment This third embodiment is a method in which the first and second embodiments are combined to record both the erase sequence number and the initialization time. As shown in FIG. 12, the erase sequence number is recorded in the 6th byte, and the year / month / day / hour / minute / second of initialization is recorded in the 19th to 21st bytes. Almost the same as the first and second embodiments, but in the algorithm for equalizing the number of times the blocks are used,
In order to improve the number of times of use of all physical blocks as efficiently as possible, when the number of times of erasure is the same, priority is given to the youngest erase sequence numbers. Further, when there is a physical block with the oldest initialization time, when it can be judged that the erase count is more efficient than others, the physical block and block erase to be allocated are assigned by an algorithm that preferentially allocates the physical block.
Management is performed.

The present invention has many embodiments and can be variously modified based on the above disclosure.
For example, the following is also included. (1) In the above-mentioned embodiment, the present invention is applied to a flash memory, but another similar memory has the same write and read functions as the flash memory and has a pre-write block erase characteristic. If there is, it is similarly applicable. (2) The physical block, which is the erase unit of the flash memory, can be similarly applied to any data unit other than the byte unit or the word unit.

[0075]

As described above, the present invention has the following effects. (1) On an extended storage device that uses a flash memory,
It has a control structure that reduces the number of rewrites of the flash memory and also loads the execution program in the main memory.
The program can be executed on the flash type memory without being loaded. Further, even if the auxiliary storage device has a control structure for reducing the number of times of rewriting, the data structure can be stored with less waste.

(2) Since the area for the information table such as the number of times of rewriting of each block is provided in the block, it is not necessary to provide another memory, and the cost can be reduced. In particular, the expansion storage device and the auxiliary storage device can be mixed on one flash type memory, and the space saving and cost reduction of the system can be achieved.

(3) Physical block valid / transitional / invalid /
Since it has a status flag of initialization, it is effective for recovery from a stop due to an abnormality in the computer system and data restoration.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a system using one embodiment of the present invention.

FIG. 2 is a diagram showing a software structure in one embodiment.

FIG. 3 is a diagram showing a memory map in which physical blocks are allocated in a flash memory according to one embodiment.

FIG. 4 is a diagram showing an example in which one execution program area and a plurality of data file areas are assigned to physical blocks.

FIG. 5 is a diagram showing an example in which a plurality of execution program areas and a plurality of data file areas are assigned to physical blocks.

FIG. 6 is a diagram showing an example of a data record packet in a data file area and an example of a storage method.

FIG. 7 is a diagram showing an example in which a flash memory with a block erase unit of 64 Kbytes is divided into physical block units to secure a block header of 256 bytes.

FIG. 8 is a diagram showing an example of a memory map in which the flash memory used in the first embodiment is divided into an execution program area and a data file area.

FIG. 9 is a diagram showing an example of a memory map of a physical block header used in the first embodiment.

FIG. 10 is a diagram showing a part of a physical block header and a sequence according to the first embodiment.

FIG. 11 is a diagram showing an example of a memory map of a physical block header used in the second embodiment.

FIG. 12 is a diagram showing an example of a memory map of a physical block header used in the second embodiment.

[Explanation of symbols]

10 ... Processor 12 ... Flash memory 14 ... Flash memory control device 16 ... RAM 20 ... Operating system 22 ... Application software 24 ... Driver layer 26 ... Flash management manager 30A, 31A, 38A, 39A, 3 (n-1) A, 3
nA, 40A ... Header areas 30B, 31B, 38B, 39B, 3 (n-1) B, 3
nB, 40B ... Storage area 32 ... Execution program area 42 ... Data record packet 42A ... Data record header 42B ... Data record 42C ... Data record footer

Continuation of front page (56) Reference JP-A-8-272654 (JP, A) JP-A-6-322795 (JP, A) JP-A-6-250798 (JP, A) JP-A-7-200418 (JP , A) JP 8-172373 (JP, A) JP 7-160597 (JP, A) JP 9-297713 (JP, A) JP 6-175917 (JP, A) JP 11-96779 (JP, A) JP 59-58699 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 3/06-3/08 G06F 12/00-12 / 06 G06F 12/16 G11C 16/02

Claims (2)

(57) [Claims] 1. A flash type memory capable of erasing stored contents in block units includes first, second and third blocks, and the first block includes a header area for storing management information of the block, The third block has a storage area for storing a data file divided into blocks, and the third block has a header area for storing management information of a block in which an execution program file is stored and an execution divided for each block. When the second block is adjacent to the third block and the execution program file exceeds the capacity of the storage area for storing the execution program file of the third block, the second block is adjacent to the third block. , The third block is provided with a storage area for storing subsequent data in which the execution program file is divided and stored. Characteristic flash type memory. 2. A means for allocating an execution program file to a plurality of adjacent second and third blocks, and storing management information of blocks to which the execution program files are allocated in the third block. The flash memory management apparatus according to claim 1, further comprising: