JP2004038595A - Information processor, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processor for effectively utilizing an unused marginal area in a cluster which is considered to be under usage in an FAT file system while keeping compatibility with the FAT file system. <P>SOLUTION: A temporary file management table 22 is arranged separately from a FAT management table 21. A sector which is left unused in the cluster which is used in a FAT is retrieved by a free sector obtaining means 34, a data write means 35 writes data in it, and a data reading means 36 reads the data. Thus, the unused marginal area of the cluster which is partially being used is effectively utilized while keeping compatibility with the FAT file system through the use of a comparatively simple method. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an information processing apparatus and a program, and more particularly, to an information processing apparatus and a program for effectively using an information storage unit.
[0002]
[Prior art]
A flash memory is a type of EEPROM (Electrically Erasable and Programmable Read Only Memory), but is a memory configured to be able to erase in block units or collectively, while a normal EEPROM erases one byte at a time. . Data can be rewritten relatively freely and repeatedly, does not require a backup power supply, and has a simple configuration, so that the unit cell area is smaller than that of a RAM. Also, the number of times of writing and erasing is guaranteed to be about 100,000 times. Further, the storage capacity is wide ranging from several Mbytes to about 512 Mbytes. For this reason, it is used not only for storing a BIOS (basic input / output system) of a personal computer or the like, but also for being widely used as an on-board memory.
By the way, flash memory elements have different specifications depending on the maker and the model number. In particular, since the block size, which is the maximum unit of data that can be transferred at one time, differs depending on the storage capacity, the control of the element depends on the difference. There was a problem that the method and processing method had to be changed.
[0003]
As means for solving this problem, there has been reported a method of managing a recording area of a flash memory using a management method called a FAT (File Allocation Table) file system, which is used for file management on a hard disk device in a conventional information recording apparatus. ing. In this method, the recording area of the flash memory is divided into a plurality of virtual sectors, which are small data storage areas, like a hard disk, and a group of the plurality of virtual sectors is defined as a virtual cluster. The unit of access to the information recording device is this sector. The table that stores the usage status of the cluster is the FAT.
[0004]
The contents of the FAT indicate the use status of the corresponding cluster, and include information such as whether or not the file continues to the next cluster when in use. The size of a sector (sector size) is 512 bytes or the like, and the size of a cluster (cluster size) is 1 kbyte in FAT in MS-DOS, 32 kbytes in FAT16 adopted from MS-DOS 3.0, and Windows (R). ) 95 is 4 kbytes in FAT32. If the cluster size is large, management and access are easy, but if the cluster size is too large, the utilization efficiency of the memory area of the disk device deteriorates.
[0005]
In the FAT disk file system, when writing normal data, FAT cluster information (recording the used / unused state of the cluster as the data storage area) in ascending order of the directory number which is a table for managing files according to logical addresses ), And search for an unused cluster. Next, data is stored in the unused cluster data, and the directory structure and the FAT are updated.
[0006]
FIG. 7 is an explanatory diagram showing a directory structure. FIG. 8 is an explanatory diagram showing the FAT.
The directory structure in FIG. 7 records a file name, an extension indicating the type of the OS in which the file is managed, an attribute indicating the number of bytes and creation date and time, and a FAT entry indicating a start position on the FAT. The FAT of FIG. 8 records cluster information indicating the used / unused state of the data storage area, and information indicating which cluster continues the file of the cluster or continues here.
[0007]
When searching for an unused area when writing data, the corresponding FAT entry is referenced from the directory in FIG. 7 and the cluster information is referenced from the FAT in FIG. As shown in the flowchart of FIG. 9, if the data storage area is unused (that is, cluster information = 0), data is stored in that cluster and the status of the FAT cluster is unused (cluster information = 0). Is rewritten to use (cluster information = 1). Further, the directory structure is rewritten. Here, the rewriting of the directory structure includes a FAT entry (indicating a FAT number) assigned to the directory number, a file name, an extension, and the like.
On the other hand, if the data storage area is in use (cluster information = 1), the above procedure is repeated for the next directory. Here, the search order is performed in ascending order of the directory. Further, the directory number and the FAT entry are fixed.
[0008]
By the way, when the storage area of the flash memory is managed by a file system such as the FAT file system, the memory capacity is processed in units of logical clusters, and files are created in units of logical clusters. Therefore, the file is always stored from the beginning of the cluster. In addition, one cluster includes only one file. Therefore, an unused sector may occur in the cluster. When a part of the cluster is in use, the cluster information becomes 1, and even if an unused sector remains, it cannot be used in the FAT file system.
[0009]
[Problems to be solved by the invention]
As described above, when the flash memory is managed by the file system, unused sectors of the cluster may be generated at the end of the file. It is natural that this unused sector is wasted at all.
The present invention solves this problem in a relatively simple manner, and can effectively utilize unused sectors of partially used clusters while maintaining compatibility with the FAT file system. It is an object to realize an information processing device and a program for executing a method of using a memory.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises an information storage means, divides a storage area of the information storage means into a plurality of primary divided data storage areas, and divides the primary divided data storage area into a plurality of secondary divided data In an information processing apparatus which divides a storage area and manages the use status of the data storage area with a management table, a primary split data storage area management which manages the usage state of the primary split data storage area with a primary split data storage area management table Means, and secondary division data storage area management means for managing the use status of the secondary division data storage area in a secondary division data storage area management table.
Thus, while maintaining compatibility with the management of the primary divided data storage area by the management table in a relatively simple manner, the storage of unused secondary divided data in the data storage area that is being used on the management table is performed. An information processing device capable of separately managing an area can be realized.
[0011]
Also, in the present invention, the primary divided data storage area management table stores information as to whether or not the secondary divided data storage area is in use in the primary divided data storage area. The table stores the use statuses of all the secondary divided data storage areas in the first primary divided data storage area.
Thus, it is possible to realize an information processing apparatus capable of separately managing the secondary divided data storage area in the primary divided data storage area in use by the secondary divided data storage area management table.
[0012]
Further, the secondary divided data storage area management means of the present invention manages an unused secondary divided data storage area in the primary divided data storage area which is determined to be in use on the primary divided data storage area management table. A secondary divided data storage area management table initializing means for initializing the secondary divided data storage area management table, and an unused part in the primary divided data storage area which is regarded as being used on the primary divided data storage area management table. An unused secondary divided data storage area searching means for searching the secondary divided data storage area and registering it in the secondary divided data storage area management table; and an unused secondary data storage area corresponding to the data length from the secondary divided data storage area management table. A data writing unit for writing data by searching for a secondary divided data storage area; and a data reading unit for reading data written by the data writing unit. Reading means, and secondary divided data storage area releasing means for releasing the secondary divided data storage area registered in the secondary divided data storage area management table when the primary divided data storage area management means starts operating. It is characterized by having.
Thereby, the secondary divided data storage area management which can manage the unused secondary divided data storage area separately from the primary divided data storage area management table, record data in this, and read out the recorded data. Means can be realized.
[0013]
According to the present invention, there is provided a program used in an information processing apparatus for managing an unused secondary divided data storage area in a primary divided data storage area which is determined to be in use on the primary divided data storage area management table. A secondary divided data storage area management table initialization procedure for initializing the next divided data storage area management table; and an unused secondary storage in the primary divided data storage area that is being used on the primary divided data storage area management table. An unused secondary divided data storage area search procedure for retrieving the next divided data storage area and registering it in the secondary divided data storage area management table, and an unused secondary data storage area corresponding to the data length from the secondary divided data storage area management table. A data write procedure for writing data by searching for the next divided data storage area; and reading data written in the data write procedure. Data reading procedure, and releasing the secondary divided data storage area registered in the secondary divided data storage area management table when the primary divided data storage area management means starts operating. And causing the information processing apparatus to execute the steps.
As a result, it is possible to realize a program for an information processing device that can effectively use the unused secondary divided data storage area in the data storage area that is being used on the management table.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an information processing apparatus and a program according to the present invention will be described in detail with reference to the accompanying drawings.
[0015]
FIG. 1 shows a configuration of an information processing apparatus to which the present invention is applied. In FIG. 1, reference numeral 1 denotes a CPU, reference numeral 2 denotes a RAM, reference numeral 3 denotes a ROM, reference numeral 4 denotes a flash memory, reference numeral 5 denotes an I / O interface, and reference numeral 6 denotes a bus. In this configuration, the RAM 2 functions as a main memory of the CPU 1 and a storage function of all management tables and system areas such as the FAT management table 21 and the temporary file management table 22 of the present invention, and the ROM 3 functions as a device driver, a FAT file system control block 31, The flash memory 4 shares storage functions such as a temporary file system control block 32 and a user program, and a storage function such as a data storage area, a system management area, cluster information, and bad block information. It has a function to save
Here, the FAT file system control block 31 is means for controlling the FAT for storing cluster information. The temporary file system control block 32 is means for controlling a temporary file management table for storing sector information. The temporary file system control block 32 has the functions of a temporary file initialization unit 33, a free sector acquisition unit 34, a data writing unit 35, a data reading unit 36, and a sector release unit 37. The correspondence between these and the present invention will be sequentially described in the description of the invention.
[0016]
FIG. 2 illustrates this flash memory file system in a layered structure. 2, reference numeral 11 denotes a CPU, reference numeral 12 denotes a flash memory, reference numeral 13 denotes an address bus, reference numeral 14 denotes a data bus, reference numeral 15 denotes a device driver, reference numeral 16 denotes a file system, reference numeral 17 denotes a temporary file system, and reference numeral 18 denotes a user. It is a program. The hardware area (physical area) includes a CPU 11, a flash memory 12, an address bus 13 and a data bus 14 connecting the CPU 11 and the flash memory 12, and a software area (logical area) includes a user program 18 and a peripheral device. The device driver 15 is a peripheral device management program that mediates with the flash memory 12 (here, the flash memory 12), and has a FAT-configured file system 16 connected thereto, a temporary file system 17 that manages unused sectors, and a user program 18. Have been. The device driver 15, the FAT file system 16, and the temporary file system 17 are stored in the ROM 3 together with the user program 18 and the like.
[0017]
FIG. 3 is an explanatory diagram showing the relationship between clusters and sectors. In this example, it is assumed that one sector is 512 bytes and one cluster is 32 kbytes. Therefore, one cluster is composed of 64 sectors. The cluster corresponds to the primary divided data storage area in the claims, and the sector corresponds to the secondary divided data storage area. FIG. 4 is an explanatory diagram for explaining a method of using a sector in the present invention.
Now, as shown in FIG. 4, it is assumed that 2 kbytes of data is recorded in the cluster of the flash memory in the FAT format. Assuming that a cluster on which data is recorded is a cluster 1, a blank (unused portion) of 32k-2k = 30k bytes is generated in the cluster 1. When this margin is converted into a sector, it becomes 60 sectors.
In order to manage and use such margins, the present invention provides a temporary file system.
[0018]
The operation of the temporary file system will be described with reference to the flowcharts of FIGS. When operating the temporary file system, it is checked whether the FAT is operating. If the FAT is operating in step 101, the process waits. If the FAT is not operating, the process proceeds to step 102. In step 102, the temporary file management means 33 initializes temporary file management information.
In step 103, the empty sector obtaining means 34 obtains cluster information used in the FAT and size information of a file recorded in the cluster based on the FAT management information. Margin information is obtained based on these information. This margin information is determined by searching whether there is an unused sector in the cluster used by the FAT. At this time, the search target of the margin information is limited only to the clusters used in the FAT, and the clusters not used in the FAT are not targeted.
In step 104, the blank information thus obtained is registered by attaching an ID (identification number) to the temporary file management information. The number of pieces of information to be registered is predetermined at the time of initialization by the temporary file initialization means 33.
[0019]
If the data is to be written to the temporary file system in step 105, the data writing means 35 acquires the optimal margin information corresponding to the data size from the temporary file management information in step 106, and is registered as the margin information in step 107. Write to unused sectors. In step 108, the ID is returned to the application that called the data writing means 35, and the margin information of the temporary file management information is corrected.
If it is determined in step 105 that the data is not to be written, the process proceeds to step 109. If the data is read from the temporary file system in step 109, the application passes the ID to the data reading means 36 in step 110. The data reading means 36 searches the sector indicated by the ID from the temporary file management information, reads out the data recorded in the sector in step 111, and returns the data to the application.
During the period in which the temporary file system is used, the following control is performed because it is desirable not to operate the FAT file system. If it is determined in step 109 that data reading is not to be performed, and if the FAT file system is to be operated in step 112, the sector registered in the temporary file management information is deleted using the sector release means 37 in step 113. The file is released, the temporary file system is invalidated in step 114, and the process moves to the FAT file system and ends. The present invention can be variously modified within the scope of the invention. For example, steps 105, 106, 107, 108 and steps 109, 110, 111 can be interchanged.
[0020]
【The invention's effect】
As described above, according to the present invention, a temporary file system is provided separately from the FAT file system to manage the sectors remaining unused in the cluster used by the FAT. By using a simple method, it is possible to effectively use the unused margin area of a partially used cluster while maintaining compatibility with the FAT file system. Can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an information processing apparatus to which the present invention is applied.
FIG. 2 is a diagram showing a layer configuration image of a flash memory file system of the present invention.
FIG. 3 is an explanatory diagram showing the relationship between clusters and sectors.
FIG. 4 is an explanatory diagram for explaining a method of using an unused sector in the present invention.
FIG. 5 is a flowchart showing the processing operation of the temporary file system of the present invention.
FIG. 6 is a flowchart showing the processing operation of the temporary file system of the present invention.
FIG. 7 is an explanatory diagram showing a directory structure.
FIG. 8 is an explanatory diagram showing a FAT.
FIG. 9 is an explanatory diagram showing a conventional data writing procedure.
[Explanation of symbols]
1,11 CPU
2 RAM
3 ROM
4, 12 Flash memory 5 I / O interface 6 Bus 13 Address bus 14 Data bus 15 Device driver 16 File system 17 Temporary file system 18 User program 21 FAT management table 22 Temporary file management table 31 FAT file system control block 32 Temporary file system Control block 33 Temporary file initialization means 34 Free sector acquisition means 35 Data writing means 36 Data reading means 37 Sector release means

Claims (4)

Comprising information storage means,
Dividing the storage area of the information storage means into a plurality of primary divided data storage areas,
Dividing the primary divided data storage area into a plurality of secondary divided data storage areas,
In an information processing apparatus that manages the use status of the data storage area with a management table,
Primary divided data storage area management means for managing the usage status of the primary divided data storage area in a primary divided data storage area management table,
An information processing apparatus, comprising: a secondary divided data storage area management unit that manages a use state of the secondary divided data storage area in a secondary divided data storage area management table. The information processing device according to claim 1,
The primary divided data storage area management table stores information on whether or not the secondary divided data storage area is in use in the primary divided data storage area,
The information processing apparatus according to claim 1, wherein the secondary divided data storage area management table stores usage statuses of all the secondary divided data storage areas in the first primary divided data storage area. The secondary divided data storage area management means,
Secondary divided data for initializing a secondary divided data storage area management table for managing an unused secondary divided data storage area in a primary divided data storage area which is regarded as being used on the primary divided data storage area management table Storage area management table initialization means;
An unused secondary that searches for an unused secondary divided data storage area in the primary divided data storage area that is being used on the primary divided data storage area management table and registers the unused secondary divided data storage area in the secondary divided data storage area management table Division data storage area search means;
Data writing means for writing data by searching for an unused secondary divided data storage area according to the data length from the secondary divided data storage area management table,
Data reading means for reading data written by the data writing means;
Secondary division data storage area release means for releasing the secondary division data storage area registered in the secondary division data storage area management table when the primary division data storage area management means starts operating. The information processing apparatus according to claim 1, wherein: A program used in the information processing apparatus according to claim 1,
Secondary divided data for initializing a secondary divided data storage area management table for managing an unused secondary divided data storage area in a primary divided data storage area which is regarded as being used on the primary divided data storage area management table A storage space management table initialization procedure,
An unused secondary that searches for an unused secondary divided data storage area in the primary divided data storage area that is being used on the primary divided data storage area management table and registers the unused secondary divided data storage area in the secondary divided data storage area management table A divided data storage area search procedure;
A data writing procedure for writing data by searching for an unused secondary divided data storage area according to the data length from the secondary divided data storage area management table,
A data reading procedure for reading data written in the data writing procedure;
A secondary divided data storage area release procedure for releasing the secondary divided data storage area registered in the secondary divided data storage area management table when the primary divided data storage area management means starts operating; A program characterized by being executed by a user.

Images