JP2008009688A - Data access system, data access program, and data access method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data access system, a data access program and a data access method for suitably improving the processing efficiency of the writing processing of data in a storage medium. <P>SOLUTION: This data access system 100 is provided with a cluster continuity analysis part 10 for analyzing the address continuity of an empty cluster region in a second storage device 300 detected an empty cluster region detection part 18; a reading part 12 for reading a data file from a first storage device 200; a model specification part 14 for specifying the model of the second storage device 300; a memory capacity comparison part 16 for comparing the memory capacity value of the second storage device 300 with a predetermined threshold; an empty cluster region detection part 18 for detecting the empty cluster region for the data quantity of the read data file in the second storage device 300 based on the specification result and the comparison result; and a writing part 20 for writing the data file in the empty cluster region based on the detection result or the analysis result. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a system for performing data access to a storage medium, and more particularly, to a data access system, a data access program, and a data access method suitable for performing efficient data access.

  2. Description of the Related Art Conventionally, there is a FAT file system that employs a FAT type format as a data access technology to a disk type storage medium (hereinafter referred to as a storage disk). In the FAT file system, the storage area of the storage disk is divided into units called sectors of hundreds to thousands of bytes. A unit called a cluster in which one or more continuous sectors are combined into one is used as a basic access unit. The FAT type (FAT12, FAT16, FAT32, etc.) and the cluster size are determined by the storage capacity (memory size) of the storage disk. In addition, a FAT (File Allocation Table) is stored at a specific position on the storage disk formatted in the FAT format. The FAT is a data table that stores, for each file, which cluster on the storage disk is used in what order to store the file.

In this FAT file system, data (files) are read from and written to the storage disk in units of clusters. Therefore, when the cluster size is small and the file size is large, the number of accesses increases, so processing efficiency is increased. There was a problem that would decrease.
As a technique for solving such a problem, there is a file system described in Patent Document 1.

The file system of Patent Literature 1 searches for a continuous free cluster area of a storage medium in advance based on management area information (FAT) for managing the data arrangement of the storage medium file in units of clusters, and stores its position information (first Data table). When writing a file (data) to a storage medium, the data table is referenced to detect a continuous free cluster area that satisfies the capacity of the stored file, and the file is continuously connected to the detected cluster area. And write.
JP 2002-91806 A

  However, in the prior art disclosed in Patent Document 1, data is written only in a continuous free cluster area at the time of file writing, so that the discontinuous free cluster area is not used. . For this reason, when there are many discontinuous free clusters, or when the storage medium has a relatively small memory size, there arises a problem that the memory use efficiency is greatly deteriorated. This problem is also described in Patent Document 1, and it is described that processing is performed with normal cluster unit access when high speed access is not required.

In the prior art disclosed in Patent Document 1, since the above-described continuous data writing process is performed regardless of the capacity of the storage medium, for example, for a storage medium having a relatively small memory capacity, there are almost no continuous free clusters. In spite of the absence, the processing such as the above-mentioned table processing and structure update processing is performed, which may reduce processing efficiency.
Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and improves the processing efficiency of the data writing process to the storage medium, and also improves the memory usage efficiency. It is an object of the present invention to provide a data access system, a data access program, and a data access method capable of performing data write processing with an appropriate write processing method in consideration of the above.

[Mode 1] In order to achieve the above object, a data access system of mode 1 includes:
A data access system for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium Continuity analysis means;
Reading means for reading the data from the first storage medium based on the analysis result of the first continuity analysis means;
Based on the memory management information of the second storage medium and the information on the data amount of the data read by the reading means, the number of free small memory areas corresponding to the amount of data in the second storage medium is detected. Memory area detection means;
Second continuity analyzing means for analyzing the continuity of addresses in a number of free small memory areas corresponding to the amount of data detected by the free small memory area detecting means;
Writing means for writing the data to the second storage medium based on the analysis result of the second continuity analysis means;
The reading means, for a plurality of consecutive small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity that is the minimum number of accesses. For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
For the plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the writing means includes a plurality of free small memory areas for each data capacity corresponding to the minimum access count. For the number of free small memory areas corresponding to the amount of data, and the small free memory area of the address that is discontinuous with the address of the other free small memory areas. The data is written for each size of the memory area.

  With such a configuration, the first continuity analysis unit, based on the memory management information of the first storage medium and the information of the data read from the first storage medium, stores the data in the first storage medium. It is possible to analyze the continuity of the address of the stored small memory area, and based on the analysis result of the first continuity analyzing means, the address where the data is stored in the first storage medium is read by the reading means For the plurality of continuous small memory areas, the data for the plurality of small memory areas is read for each data capacity that is the minimum number of accesses, and other small memory areas in the first storage medium For the small memory area where the data of the address that is discontinuous with the address is stored, the data is read for each size of the small memory area. It is possible.

  Further, the number corresponding to the data amount in the second storage medium based on the memory management information of the second storage medium and the data amount information of the data read by the reading unit by the free small memory area detection unit , The second continuity analysis means can determine the continuity of addresses in the number of free small memory areas corresponding to the amount of data detected by the free small memory area detection means. A plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data by the writing means based on the analysis result of the second continuity analyzing means. For each of the data capacities corresponding to the minimum number of accesses, the data for the plurality of free small memory areas is written, and the number corresponding to the data amount In come the small memory area for the free small memory area of the address to be the address and discontinuous other free small memory space, it is possible to write the data for each size of the small memory area.

  Therefore, when the data to be read is stored in a small memory area having continuous addresses, data corresponding to the data amount in the area is read with the minimum number of accesses, so that the data read efficiency can be improved. In addition, in a plurality of free small memory areas having consecutive addresses in a number of free small memory areas corresponding to the data amount, data corresponding to the data amount of the area is written with the minimum number of accesses. In addition, in the number of free small memory areas corresponding to the amount of data, data is written for each data size of the small memory area in the free small memory area whose address is discontinuous with the addresses of the other free small memory areas. Is done.

  Thus, by applying this embodiment to a system that accesses data for each data size of a small memory area (for example, a FAT file system), a plurality of free small memory areas (for example, cluster areas) having consecutive addresses are used. Since the number of accesses in reading and writing of data can be reduced, it is possible to improve the efficiency of reading data from the first storage medium and the efficiency of writing the read data to the second storage medium. The effect is obtained. In addition, since data is written even in isolated small free memory areas where the addresses are discontinuous, the processing efficiency of the writing process can be improved without deteriorating the memory usage efficiency. can get. That is, the efficiency of data copy processing from the first storage medium to the second storage medium can be improved.

  Here, the storage medium is a semiconductor storage medium such as RAM, a magnetic storage type storage medium such as FD or HD, an optical storage type / optical reading type storage medium such as DVDRAM, or a magnetic storage type / optical reading type such as MO. It is a type of storage medium, and includes any storage medium regardless of writing / reading methods such as electrical, magnetic, and optical. The following data access program and data access method are the same.

  The memory management information is, for example, FAT in a known FAT file system, etc., and the location information of each small memory area and connection information of each small memory area in which data is stored (for example, FAT in the FAT file system). Entry value) and the like. The following data access program and data access method are the same.

  Further, the minimum access count is an access with a data amount within the maximum data transfer amount that can be transferred at one time by the system to which the present embodiment is applied in the data read processing and data write processing to the storage medium. This is the smallest number of accesses required to complete the writing. For example, the writing means detects four consecutive small memory areas each having 512 bytes, when the target data is 1 Mbyte and the maximum data transfer amount is 2048 bytes. In one small memory area, data of 2048 bytes of the target data is written by one access (minimum access count). The same applies to reading. The following program forms and method forms are the same. The following data access program and data access method are the same.

  The analysis of address continuity means that, for example, when one data file is divided and stored over a plurality of small memory areas, addresses (numbers) for managing the positions of these small memory areas are stored. Is to determine by calculation or the like from the address value of the small memory area whether or not the addresses are continuous. The analysis result includes, for example, information on a writing method for each small memory area in addition to continuous and discontinuous information of addresses of each small memory area in which the data file is written. The following data access program and data access method are the same.

[Mode 2] Furthermore, the data access system of mode 1 is the data access system of mode 1,
Comparing means for comparing a value relating to the memory capacity of the second storage medium with a predetermined threshold value,
When the value relating to the memory capacity of the second storage medium is equal to or greater than the predetermined threshold, the free small memory area detecting means continuously includes addresses corresponding to the data amount in the free small memory area of the second storage medium. It is designed to detect multiple free small memory areas,
When the value relating to the memory capacity of the storage medium is less than the predetermined threshold by the comparison, the writing means has a plurality of consecutive free addresses in the number of free small memory areas corresponding to the data amount. The data for the plurality of free small memory areas is written for each data capacity that is the minimum number of accesses to the small memory area, and other free small areas in the number of free small memory areas corresponding to the data amount are written. The data is written for each size of the small memory area in an empty small memory area that is discontinuous with the address of the memory area. The data is written for each data capacity that is the minimum number of accesses to a plurality of free small memory areas.

  With such a configuration, it is possible to compare the value related to the memory capacity of the storage medium with a predetermined threshold value by the comparison means, and the free small memory area detection means can compare the memory capacity of the storage medium. When the value relating to is equal to or greater than the predetermined threshold, it is possible to detect a plurality of free small memory areas having addresses corresponding to the data amount among free small memory areas of the storage medium.

  Further, the writing means, when the value relating to the memory capacity of the storage medium is less than the predetermined threshold by the comparison, a plurality of consecutive addresses in the number of free small memory areas corresponding to the data amount. Writing the data for the plurality of free small memory areas for each data capacity that is the minimum number of accesses to the free small memory area, and in other free small memory areas corresponding to the amount of data, A first write process is performed to write the data for each size of the small memory area in an empty small memory area that is discontinuous with the address of the small free memory area. A second writing process for writing the data for each data capacity that is the minimum number of accesses to a plurality of continuous small free memory areas having addresses corresponding to the data amount. It is possible to run.

Therefore, for example, when the total memory capacity (or remaining memory capacity) of the storage medium is 8 Gbytes or less, the first writing process is executed to consider the memory usage efficiency, and the total memory capacity is more than 8 Gbytes. When larger, it is possible to increase the efficiency of the writing process by executing the second writing process. As a result, an effect is obtained that data can be written by an appropriate writing processing method according to the total memory capacity (or remaining memory capacity) of the storage medium.
Here, as described above, the value relating to the memory capacity is the total memory capacity of the storage medium, the remaining memory capacity that can be stored in the storage medium, and the like. The same applies to the forms of the following programs and methods.

  The predetermined threshold varies depending on a value related to the memory capacity of the storage medium to be written. For example, when a large-capacity storage medium is to be written, a memory suitable for applying the second writing process is used. For example, the memory capacity is 8 Gbytes to 10 Gbytes based on the capacity. In other words, when the amount of data to be written is large, the time required for the writing process is significantly reduced by using the second writing process. For example, for a large-capacity storage medium such as an HDD such as an HDD. Since the memory capacity is sufficient, the second writing process is executed with emphasis on writing efficiency rather than memory usage efficiency. On the other hand, for a storage medium having a memory capacity smaller than 10 Gbytes (for example, several Kbytes to several Gbytes) such as a card-type storage medium or a storage medium mounted in an embedded product system, By using the first write process, a write process that considers not only the write efficiency but also the memory use efficiency is executed. The same applies to the forms of the following programs and methods.

[Mode 3] Furthermore, the data access system of mode 3 is the data access system of mode 2,
A specifying means for specifying the type of the second storage medium;
The writing means, when the type of the second storage medium specified by the specifying means is a specific type, based on the processing result of the comparison process, the first writing process or the second writing medium And executing the first writing process or the second writing process in a fixed manner according to the type when the process is selectively performed. .

  With such a configuration, it is possible to specify the type of the storage medium by the specifying unit, and the writing unit is configured such that the type of the storage medium specified by the specifying unit is a specific type. At one time, the first writing process or the second writing process is selectively executed based on the processing result of the comparison process, and when it is other than the specific type, The first writing process or the second writing process can be fixedly executed.

Therefore, for example, if the HDD is not a specific type and has a relatively large memory capacity, the second writing process is executed in a fixed manner, for example, installed in an embedded product system other than the specific type. The first writing process can be executed in a fixed manner if the storage medium has a relatively small memory capacity (for example, several kilobytes to several megabytes). Furthermore, for example, when the storage medium is a specific type of removable disk (for example, having a memory capacity of an intermediate capacity of several kilobytes to several gigabytes), the first document is set according to the memory capacity. It is possible to select and execute either the write-in process or the second write process.
As a result, the first writing process and the second writing process can be executed in a fixed and selective manner according to the type and capacity of the storage medium, so that a more efficient writing process is executed. The effect of being able to be obtained.

[Mode 4] Furthermore, the data access system of mode 4 is the same as the data access system of mode 1,
The storage medium has a FAT (File Allocation Table) type format in which the storage area is divided into sectors each having a predetermined memory size and is divided into clusters each composed of one or more sectors.
The memory management information is a FAT (File Allocation Table) composed of data storage state information of the cluster unit of the storage medium,
The small memory area is a memory area of the cluster unit.
With such a configuration, it is possible to obtain an effect that more efficient writing processing can be executed on a storage medium compatible with a known FAT file system.

[Mode 5] On the other hand, in order to achieve the above object, a data access program of mode 5
A data access program for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size, based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium A continuity analysis step;
A reading step for reading the data from the first storage medium based on the analysis result of the first continuity analysis step;
An empty small memory area for detecting an empty small memory area corresponding to the data amount in the second storage medium based on the memory management information of the second storage medium and the data amount information of the data read in the reading step A detection step;
A second continuity analysis step for analyzing the continuity of addresses in the free small memory area detected in the free small memory area detection step;
A program for causing a computer to execute a process consisting of a writing step of writing the data to the second storage medium based on the analysis result of the second continuity analysis step;
In the reading step, for a plurality of continuous small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity corresponding to the minimum access count For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
In the writing step, for a plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the plurality of free small memories for each data capacity corresponding to the minimum access count. In addition to writing the data for the area, the number of free small memory areas corresponding to the amount of data corresponds to the free small memory area whose address is discontinuous with the addresses of other free small memory areas. The data is written for each size of the small memory area.

  With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as the data access system according to claim 1 can be obtained.

[Mode 6] On the other hand, in order to achieve the above object, the data access method of mode 6 includes:
A data access method for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium A continuity analysis step;
A reading step for reading the data from the first storage medium based on the analysis result of the first continuity analysis step;
An empty small memory area for detecting an empty small memory area corresponding to the data amount in the second storage medium based on the memory management information of the second storage medium and the data amount information of the data read in the reading step A detection step;
A second continuity analysis step for analyzing the continuity of addresses in the free small memory area detected in the free small memory area detection step;
A writing step of writing the data to the second storage medium based on the analysis result of the second continuity analysis step,
In the reading step, for a plurality of continuous small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity corresponding to the minimum access count For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
In the writing step, for a plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the plurality of free small memories for each data capacity corresponding to the minimum access count. In addition to writing the data for the area, the number of free small memory areas corresponding to the amount of data corresponds to the free small memory area whose address is discontinuous with the addresses of other free small memory areas. The data is written for each size of the small memory area.
Thereby, the same operation and effect as those of the data access system of aspect 1 can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 11 are diagrams showing embodiments of a data access system, a data access program, and a data access method according to the present invention.
First, the configuration of the data access system according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a functional configuration of a data access system 100 according to the present invention.

  As shown in FIG. 1, the data access system 100 includes a first storage device 200 having a FAT (File Allocation Table) type format, which is a storage device on the data file reading side, and a read from the first storage device 200. The data file is connected to a second storage device 300 that is also FAT-formatted, which is a storage device to which the data file is written, and the data file stored in the first storage device 200 is read out. It has a function of executing a copying process for writing the read data file into the second storage device 300.

  The first storage device 200 has a configuration in which a known FAT type format in which the storage area is divided into a plurality of small memory areas called clusters is divided into a predetermined memory amount unit. The first FAT is stored. Here, the first FAT is a data table including information indicating how data files stored in the storage area are stored in each cluster. By referring to the first FAT, it is possible to easily know in which cluster address the cluster (data area) stores a file (data) having a data amount for a plurality of clusters. As a result, it can be determined whether each of the files is stored in a cluster area having discrete cluster addresses or whether a part or all of the files are stored in cluster areas having continuous cluster addresses.

Similar to the first storage device 200, the second storage device 300 has a configuration in which a known FAT format is applied, and the second FAT is stored in the specific cluster area. Similar to the first FAT, the second FAT is a data table including information indicating how the data files stored in the storage area are stored in each cluster.
Here, each of the first storage device 200 and the second storage device 300 has information on memory capacity (hereinafter referred to as memory capacity information) in a specific cluster of the storage area. In this embodiment, the memory capacity information includes information on total memory capacity, information on free memory capacity, and the like.

  In addition, the flow of various data between the blocks shown in FIG. 1 includes the first storage device 200 as a data file copy source (data file read destination) and the second storage device 300 as a data file copy destination (reading data). Shows the flow when the data file is written to. Therefore, for example, when copying a data file from a storage device such as an on-board memory of a device in which the data access system 100 is incorporated to an externally connected card type memory, the on-board memory is the first storage device. 200, and the card-type memory becomes the second storage device 300. On the other hand, when copying a data file from an externally connected card type memory to the onboard memory, the card type memory becomes the first storage device 200 and the onboard memory becomes the second storage device 300.

  Further, not limited to this example, even between two storage devices included in a device in which the data access system 100 is incorporated, or between two storage devices externally connected to a device in which the data access system 100 is incorporated, If data access processing is executed by the data access system 100, the data file copy source is the first storage device 200 and the data file copy destination is the second storage device 300.

  The data access system 100 further analyzes the address continuity of the cluster area in which the read target data file is stored in the first storage device 200, and the second storage device 300 detected by the free cluster area detection unit 18 described later. A cluster continuity analysis unit 10 that analyzes the address continuity of an empty cluster area in the memory, and a reading unit 12 that reads out a read target data file stored in the first storage device 200 based on the analysis result of the cluster continuity analysis unit 10. It has a configuration that includes.

  The cluster continuity analysis unit 10 has a function of analyzing the continuity of cluster addresses in the cluster area in which the read target data file is stored, based on a first FAT (File Allocation Table) included in the first storage device 200. . Specifically, for a plurality of cluster areas in which the data file to be read is stored, it analyzes (determines) whether the addresses of each cluster are continuous based on the first FAT, and generates information on the analysis result To do. The analysis result information is passed to the reading unit 12.

  Based on the analysis result of the cluster continuity analysis unit 10, the reading unit 12 has a function of reading the read target data file from the cluster area where the read target data file of the first storage device 200 is stored. Specifically, for an area where cluster addresses are continuous, data is read for each data amount corresponding to the number of clusters with the smallest number of accesses, and from an isolated cluster area where the cluster addresses are discontinuous, The stored data is read for each data amount of each cluster.

  The data access system 100 further includes a model specifying unit 14 for specifying the model of the second storage device 300, a memory capacity comparison unit 16 for comparing the memory capacity value of the second storage device 300 with a predetermined threshold, and the specifying result. Based on the comparison result, the free cluster area detecting unit 18 that detects an empty cluster area corresponding to the data amount of the data file read by the reading unit 12 in the second storage device 300, and the detection result of the free cluster area detecting unit 18 or Based on the analysis result of the cluster continuity analysis unit 10, the writing unit 20 writes the read data file in the detected empty cluster area.

  The model specifying unit 14 acquires information about the model of the second storage device 300 (hereinafter referred to as model information) from the device driver that drives the second storage device 300, and based on the acquired model information, the second It has a function of specifying the type of memory of the storage device 300. Here, the model information is information indicating the type of memory of the second storage device 300 such as an HDD, an SD card, a CF (Compact Flash (registered trademark)) card, an SMT medium (registered trademark), or an OFM (Onboard Flash Memory). Etc. are included.

  When the second storage device 300 is a specific model (hereinafter referred to as model 1 (for example, a memory of 32 Mbytes to several Gbytes class)) based on the identification result of the model identification unit 14, the memory capacity comparison unit 16 The memory capacity information of the second storage device 300 is acquired, and based on the acquired information, it is determined whether or not the total memory capacity (or the remaining memory capacity) of the second storage device 300 is equal to or greater than a predetermined threshold value. It has a function to do.

  The free cluster area detection unit 18 acquires the second FAT of the second storage device 300, and the specification result of the model specifying unit 14 is not model 1, but model 2 (for example, a memory of several kilobytes to several megabytes class) ), Based on the acquired second FAT, empty cluster areas corresponding to the data amount read by the reading unit 12 described above are detected in the order of empty addresses, regardless of whether they are continuous or discontinuous. Further, when the specification result of the model specifying unit 14 is not the model 1 but the model 3 (for example, a memory of several tens of Gbytes to several 100 Gbytes class), the reading unit 12 described above is based on the acquired second FAT. The free cluster area corresponding to the data amount read in step 1 is detected. Among the free addresses, the continuous free cluster area of the address corresponding to the data amount is detected. Skip).

  Further, the free cluster area detection unit 18 uses the same method as the above-described model 2 when the specification result of the model specification unit 14 is the model 1 and the second storage device 300 has a memory capacity less than the predetermined threshold. When the cluster area is detected and the identification result of the model identification unit 14 is model 1 and the second storage device 300 has a memory capacity equal to or greater than a predetermined threshold, the free cluster area is detected in the same manner as model 3 described above. To do.

In the present embodiment, when the identification result is model 1 and the determination result is a predetermined threshold value or more, and when the identification result is model 3, the detected vacant cluster information is displayed as a cluster continuity analysis unit. 10 is passed to the writing unit 20 without going through 10.
Based on the analysis result from the cluster continuity analysis unit 10, the writing unit 20 writes the data file read by the reading unit 12 to the empty cluster having consecutive addresses for each data amount that is the minimum number of accesses. In an isolated empty cluster in which addresses are discontinuous, writing is performed for each data amount of the cluster. When the information on the free cluster is directly received from the free cluster area detecting unit 18, the data file read by the reading unit 12 is written to the free cluster having consecutive addresses with the data amount that is the minimum access count.

  Here, the data access system 100 performs each processing in the cluster continuity analyzing unit 10, the reading unit 12, the model specifying unit 14, the memory capacity comparing unit 16, the free cluster area detecting unit 18, the writing unit 20 and the like on software. As shown in FIG. 2, the hardware configuration includes a CPU (Central Processing Unit) 60, which is a central processing unit responsible for various types of control and arithmetic processing, and a main storage device. A RAM (Random Access Memory) 62 constituting a (Main Storage) and a ROM (Read Only Memory) 64, which is a read-only storage device, are connected by various internal and external buses 68, and an input / output interface is connected to the bus 68. Via (I / F) 66 An external storage device (Secondary Storage) 200, 300 such as an HDD (Hard Disk Drive) or a card-type memory, an output device 72 such as a CRT or LCD monitor, an input device 74 such as an operation panel, mouse, keyboard or scanner, And a network L or the like for communicating with an external device (not shown).

  When the power is turned on, a system program such as BIOS stored in the ROM 64 or the like is stored in various dedicated computer programs stored in the ROM 64 in advance, or in a CD-ROM, DVD-ROM, flexible disk (FD), or the like. Various dedicated computer programs installed in the storage devices 200 and 300 via the medium or the communication network L such as the Internet are similarly loaded into the RAM 62, and in accordance with instructions described in the program loaded into the RAM 62. Each function of each unit as described above can be realized on software by the CPU 60 performing predetermined control and arithmetic processing using various resources.

Next, an example of the flow of data copy processing using the data access system 100 configured as described above will be described with reference to the flowchart of FIG. Here, FIG. 3 is a flowchart showing data copying processing in the data access system 100.
As shown in FIG. 3, the data copy process first proceeds to step S100, and in the data access system 100, a copy command which is a command for copying (copying) a data file in the first storage device 200 to the second storage device 300. If it is determined that it has been received (Yes), the process proceeds to step S102. If not (No), the determination process is repeated until it is received.

When the process proceeds to step S102, the cluster continuity analysis unit 10 and the reading unit 12 execute the reading process of the designated data file from the first storage device 200, and the process proceeds to step S104.
In step S104, the cluster continuity analyzing unit 10, the model specifying unit 14, the memory capacity comparing unit 16, the free cluster area detecting unit 18 and the writing unit 20 transfer the data file read by the reading unit 12 to the second storage device 300. The writing process is executed, and the process proceeds to step S106.

In step S106, the data access system 100 determines whether or not all designated data files have been copied. If it is determined that the copying has ended (Yes), the process proceeds to step S100, otherwise. In the case (No), the process proceeds to step S102.
Furthermore, the flow of data file read processing in the data access system 100 will be described with reference to FIG. Here, FIG. 4 is a flowchart showing a data file reading process in the data access system 100.

When the data file reading process is executed, as shown in FIG. 4, the process first proceeds to step S200, and the cluster continuity analysis unit 10 acquires the first FAT of the first storage device 200 and proceeds to step S202. .
In step S202, the cluster continuity analysis unit 10 analyzes the continuity of the cluster address in which the designated read target data (data file) is stored, and proceeds to step S204.

  In step S204, based on the analysis result in step S202, the reading unit 12 performs optimum reading for reading data for each data amount corresponding to the minimum number of accesses for cluster regions having continuous cluster addresses. For the cluster area, normal reading is performed to read data for each data amount of the cluster, and the process proceeds to step S206.

In step S206, the reading unit 12 determines whether or not the reading of the data file to be read is completed. If it is determined that the reading is completed (Yes), the read data file is passed to the writing unit 20 and a series of operations are performed. The process is terminated and the process returns to the original process.
Furthermore, the flow of the data file writing process in the data access system 100 will be described with reference to FIG. Here, FIG. 5 is a flowchart showing a data file writing process in the data access system 100.

  When the data file writing process is executed, as shown in FIG. 5, first, the process proceeds to step S300, where the model specifying unit 14 acquires model information from the device driver that drives the second storage device 300, and the memory capacity In the comparison unit 16, the memory capacity information is acquired from the second storage device 300, and the process proceeds to step S302. Specifically, a command for acquiring model information is transmitted to a device driver (software) executed to drive the second storage device 300, and the model information is acquired.

In step S302, the model identification unit 14 identifies the memory type of the second storage device 300 from the model information acquired in step S300, and passes the identification result to the memory capacity comparison unit 16 and the free cluster area detection unit 18. The process proceeds to S304.
In step S304, the memory capacity comparison unit 16 determines whether or not the second storage device 300 is a memory of a specific type (model 1) based on the determination result of step S302. If “Yes”, the process proceeds to step S306. If not (No), the process proceeds to step S328.

When the process proceeds to step S306, the memory capacity comparison unit 16 compares the memory capacity information acquired in step S300 with a predetermined threshold value, passes the comparison result to the free cluster area detection unit 18, and proceeds to step S308. .
In step S308, in the free cluster area detection unit 18, if the comparison result in step S306 is equal to or greater than a predetermined threshold (Yes), the process proceeds to step S310, and if not (No), the process proceeds to step S318.

When the process proceeds to step S310, the free cluster area detection unit 18 acquires the second FAT from the second storage device 300, and the process proceeds to step S312.
In step S312, the free cluster area detection unit 18 detects continuous free cluster areas of cluster addresses corresponding to the data amount of the data file to be written to the second storage device 300, and writes the detected cluster address information to the writing unit 20. And the process proceeds to step S314.

  In step S314, the writing unit 20 writes the data for each data amount that is the minimum number of accesses to the free cluster area having consecutive cluster addresses, based on the cluster address information of the free cluster area detected in step S312. Writing is performed and the data file read by the reading unit 12 is written in the empty cluster area, and the process proceeds to step S316.

In step S316, the writing unit 20 determines whether or not the writing of the data file to the free cluster area detected in step S312 has been completed. If it is determined that the writing has been completed (Yes), a series of processing is performed. If the process ends and returns to the original process, otherwise (No), the process proceeds to step S314.
On the other hand, if the memory capacity of the second storage device 300 is less than the threshold value in step S308, or if the second storage device 300 is model 2 and the process moves to step S318 in step S328, the free cluster area detection unit 18 The second FAT is acquired from the second storage device 300, and the process proceeds to step S320.

  In step S320, the free cluster area detection unit 18 detects free cluster areas corresponding to the data amount of the data file to be written to the second storage device 300 in the order of cluster addresses, and the detected cluster address information is used as cluster continuity. It passes to the analysis part 10 and transfers to step S322. Specifically, the empty cluster areas are detected in the order of addresses until the data amount is satisfied, regardless of whether the cluster addresses are continuous.

  In step S322, the cluster continuity analysis unit 10 analyzes the continuity of the cluster address based on the cluster address information of the free cluster detected in step S320, passes the analysis result to the writing unit 20, and proceeds to step S324. To do. In the present embodiment, the analysis result is, for example, information in which each cluster address of a free cluster is associated with a writing method (normal writing or optimum writing).

  In step S324, based on the analysis result in step S322, the writing unit 20 performs the above-described optimal writing on two or more free cluster areas having continuous cluster addresses, and the cluster addresses become discontinuous. For the free cluster area, normal writing is performed in which data is written for each data amount of the cluster, and the data file read by the reading unit 12 is written to the free cluster area detected in step S320, and step S326 is performed. Migrate to

In step S326, the writing unit 20 determines whether or not the writing of the data file to the free cluster area detected in step S320 is completed. If it is determined that the writing is completed (Yes), a series of processing is performed. When the process ends and the process returns to the original process, otherwise (No), the process proceeds to step S324.
On the other hand, if the second storage device 300 is not a specific type (model 1) of memory in step S304 and the process proceeds to step S328, the memory capacity comparison unit 16 determines whether the second storage device 300 is based on the specification result of step S302. It is determined whether or not the memory 300 is a low-capacity memory model (model 2). If it is determined that the model 300 is model 2 (Yes), the process proceeds to step S318; otherwise (No), the process proceeds to step S310. Transition.

Next, the operation of the present embodiment will be described with reference to FIGS.
Here, FIG. 6 is a diagram illustrating an example of a writing processing method (algorithm) for the type (model) of the storage device and the disk capacity. FIG. 7 is a diagram illustrating an example of the first FAT of the first storage device 200. FIG. 8 is a diagram illustrating an example of the second FAT of the second storage device 300. FIG. 9 is a diagram illustrating an example of the second FAT after the writing process to the cluster area in which continuous and discontinuous cluster areas are mixed. FIG. 10 is a diagram illustrating an example of the second FAT after the writing process to the cluster regions that are all discontinuous. Further, FIG. 11 is a diagram illustrating an example of the second FAT after the writing process to the cluster area that is all continuous.

  Here, it is assumed that the memory size of the cluster area of the first storage device 200 and the memory size of the cluster area of the second storage device 300 are the same size. For example, when the first storage device 200 is formatted with the size of each cluster area as “1024 bytes”, the second storage device 300 is also formatted with the size of each cluster area as “1024 bytes”.

  Hereinafter, when the second storage device is model 1 and the memory capacity is equal to or greater than a predetermined threshold, and when the second storage device is model 3, a free cluster area having consecutive cluster addresses is detected, A write processing algorithm for performing the optimum write in the detected free cluster area is defined as algorithm A. In addition, when the second storage device is model 1 and the memory capacity is less than the predetermined threshold, and when the second storage device is model 2, continuous free addresses of cluster addresses in the free cluster area detected in the order of addresses. An algorithm B is defined as a write processing algorithm for performing the above-described optimum writing in the cluster area and performing the above-described normal writing in an isolated empty cluster area having discontinuous cluster addresses.

  Here, as shown in FIG. 6, whether to use algorithm A and algorithm B fixedly or selectively is preset for the model of the storage device and its memory capacity. 6 for each model, ○ in FIG. 6 indicates that algorithm A or B is fixedly used for that model, and Δ indicates that one of algorithms A and B is stored for that model. Indicates that it is selectively used according to the memory capacity, and X indicates that the algorithm A or B is not applied to the model.

Based on the above, the actual operation of the data file copying process in the data access system 100 will be described below.
When the data access system 100 receives a command to copy the data file stored in the predetermined cluster position of the first storage device 200 to the second storage device 300 (“Yes” branch of step S100), first, the copy command The process proceeds to the reading process of the data file stored at the cluster address position specified in (Step S102).

When the reading process is started, first, the cluster continuity analysis unit 10 acquires the first FAT stored in the specific cluster area of the first storage device 200.
Here, as shown in FIG. 7, the first FAT is composed of a cluster number (cluster address) and a value of a FAT entry indicating a chain relationship of each cluster. Here, one entry of FAT is 16 bits. That is, the first storage device 200 is formatted in the FAT16 format.

  For example, as shown in FIG. 7, the FAT entry value is “EOF (value indicating the end of the data file, and the actual entry value is“ FFFFh ”)” when the value for the cluster number “02h” is viewed. It has become. This indicates that the data file is stored in only one cluster. The FAT entry values of the cluster numbers “06h to 09h” are “06h” and “07h”. This is because the cluster following the cluster of the cluster number “06h” is the cluster with the cluster number “07h”. It shows that there is. Further, the FAT entry value of the cluster number “07h” is “08h”, the FAT entry value of the cluster number “08h” is “09h”, and the FAT entry value of the cluster number “09h” is “EOF”. This indicates that the cluster having the number “07h” is followed by the cluster having “08h”, the cluster having the cluster number “08h” followed by the cluster having “09h”, and the cluster having the cluster number “09h” is the last of the data file. That is, it can be seen from the FAT entry value that one data file is stored in four consecutive cluster areas having cluster numbers “06h to 09h”.

  Also, as shown in FIG. 7, the FAT entry values of “1Ah”, “1Ch”, and “1Eh” are “1Ch”, “1Eh”, and “EOF”, respectively. In this case, these three clusters are continued, and one data file is stored in these three clusters. That is, the cluster number of the cluster area in which one data file is stored is discontinuous (here, one is skipped, but one or more may be skipped). This is a phenomenon peculiar to the file system of the FAT type format, and data is written in units of clusters. Therefore, by repeating the writing and deletion of an indefinite size data file many times, one data file becomes This is a phenomenon in which data is stored in a cluster area with discontinuous cluster numbers.

Note that the cluster number in which the FAT entry value is not set (the cluster number whose entry value is “−”) shown in FIG. 7 indicates that the cluster area is a free area (unused).
When acquiring the first FAT, the cluster continuity analysis unit 10 analyzes the continuity of the cluster address based on the cluster address value of the data file to be read designated by the copy command and the first FAT (step S202). Here, as shown in FIG. 9, the data file stored in the cluster area of the cluster numbers “06h to 09h” is read out.

  As described above, it can be seen that the cluster area of the cluster numbers “06h to 09h” in the first FAT shown in FIG. 7 is a cluster area in which the address numbers are continuous from the FAT entry value. Therefore, it can be seen that the above-described optimum reading of data is possible for this cluster area. Therefore, the cluster continuity analysis unit 10 has information on the cluster number “06h to 09h” indicating the storage location of the data file to be read, and information indicating that optimum reading is possible for the cluster area of this cluster number. Is generated as an analysis result and passed to the reading unit 12.

When the reading unit 12 receives the analysis result from the cluster continuity analysis unit 10, based on the analysis result, as shown in FIG. 8A, the reading unit 12 uses the cluster numbers “06h˜ The data stored in the cluster area corresponding to “09h” is optimally read (step S204). Here, for convenience of explanation, the maximum capacity capable of data transmission from the first storage device 200 at a time is the data amount for 8 clusters. In this case, since the data file to be read has a data amount for four clusters, the data for the four clusters are read at once and the reading process is completed (branch “Yes” in step S206).
When the data file to be copied is read out from the first storage device 200 in this way, the data access system 100 then proceeds to write processing of the read data file (step S104).

  When the writing process is started, the model specifying unit 14 acquires model information from a device driver being executed to drive the second storage device 300, and the memory capacity comparing unit 16 acquires the second storage device 300. Memory capacity information is acquired from (step S300). If the device driver has clear information for specifying the model in advance and clear information for specifying the memory capacity is stored in the specific position of the second storage device 300 in advance, those information are stored. Get information. On the other hand, when there is no clear information, information such as a product number that can identify the model is acquired, or processing for analyzing the memory capacity is performed to acquire information on the analysis result.

Here, the device driver has clear information for specifying the model of the second storage device 300, and clear information for specifying the memory capacity is stored at a specific address position of the second storage device 300. To do.
When acquiring the model information from the second storage device 300, the model specifying unit 14 specifies the model of the second storage device 300 from the model information (step S302).

  Here, as shown in FIG. 6, the model of the second storage device 300 is a fixed-type large-capacity storage device such as an HDD, a portable card type storage device such as a CF card (registered trademark) or an SD card. It is specified as any one of a device, a portable small capacity storage device such as SMT media (registered trademark), and a fixed small capacity storage device such as OFM (NAND type, NOR type). The above-described specific type (model 1) storage device is a portable card-type storage device such as a CF card (registered trademark) or an SD card. The storage device of model 2 described above is a portable small-capacity storage device such as SMT media (registered trademark) and a fixed small-capacity storage device such as OFM (NAND type, NOR type). In addition, the storage device of model 3 described above is a fixed large-capacity storage device such as an HDD.

  When the second storage device 300 is identified as the model 1 (“Yes” branch in step S304), the memory capacity comparison unit 16 then selects the memory capacity indicated by the memory capacity information (total memory capacity or remaining memory capacity). Amount) and a predetermined threshold value are compared (step S306). For example, it is assumed that the memory capacity indicated by the memory capacity information is 256 (the unit is M bytes) and the predetermined threshold is 512. In this case, the memory capacity “256” indicated by the memory capacity information is smaller than the predetermined threshold value 512 (less than the predetermined threshold value) (the branch of “No” in step S308). Selects a writing process using the algorithm B from the algorithms A and B, and first obtains the second FAT from the second storage device 300 (step S318).

Here, it is assumed that the current state of the second FAT is as shown in FIG.
The free cluster area detection unit 18 detects free clusters corresponding to the data amount of the file data read by the reading unit 12 (hereinafter referred to as a write target data file) based on the acquired second FAT (step S320). Since the free cluster area detection unit 18 has selected the algorithm B as described above, the free cluster area detection unit 18 starts from the second FAT free cluster shown in FIG. Min) free clusters. Here, free cluster areas corresponding to the four cluster numbers “05h”, “07h”, “0Ah”, and “0Bh” are detected from the second FAT shown in FIG. 8 in ascending order of the cluster numbers. Then, the detected cluster number information of the free cluster area is passed to the cluster continuity analysis unit 10.

When the cluster continuity analysis unit 10 receives information on the cluster numbers of the free cluster regions (the above four cluster numbers) from the free cluster region detection unit 18, it analyzes the continuity of the cluster numbers based on the information on the cluster numbers. (Step S322).
In this case, among the four cluster numbers “05h”, “07h”, “0Ah”, and “0Bh” corresponding to the free cluster area, the cluster numbers of “05h” and “07h” are discontinuous. It can be seen that “0Ah” and “0Bh” have consecutive cluster numbers. Therefore, the cluster continuity analysis unit 10 includes information on the cluster numbers “05h” and “07h”, information indicating that normal writing is possible for each of these cluster areas, and cluster numbers “0Ah” and “ The information “0Bh” and information indicating that optimum writing is possible for these cluster areas are generated as analysis results and passed to the writing unit 20.

When the writing unit 20 obtains the analysis result from the cluster continuity analysis unit 10, the writing unit 20 applies the data file using the algorithm B to the detected free cluster area of the second storage device 300 based on the analysis result. Writing is performed (step S324).
Specifically, the writing unit 20 applies to the cluster area corresponding to the cluster numbers “05h” and “07h” in the cluster area of the second storage device 300 for each data amount corresponding to the memory capacity of each cluster ( Write data to each cluster).

  On the other hand, the writing unit 20 writes data in the cluster area corresponding to the cluster numbers “0Ah” and “0Bh” in the cluster area of the second storage device 300 for each data amount corresponding to the minimum access count. Here, it is assumed that data of a maximum of 8 clusters can be transmitted to the second storage device 300 at a time. Therefore, since the data to be written is for two clusters, the data for two clusters is written to the cluster area corresponding to the cluster numbers “0Ah” and “0Bh” with one access. Here, the maximum data transmission amount is 8 clusters, but this is determined, for example, by some (how many clusters) the size of the data transfer buffer secured by the host application is. Therefore, depending on the type of higher-order application and other conditions, the transmission amount is not limited to 8 clusters, but other transmission amounts such as 4 clusters, 16 clusters, and 32 clusters.

  In this way, the writing of the write target data (data for 4 clusters) to the second storage device 300 is completed (“Yes” branch of step S326). By this writing process, the second FAT of the second storage device 300 is updated to the state shown in FIG. That is, the FAT entry values “07h”, “0Ah”, “0Bh”, and “EOF” are assigned to the cluster numbers “05h”, “07h”, “0Ah”, and “0Bh” that were previously free cluster areas. Each is set.

When the writing of the write target data is completed, the data access system 100 performs a process of reading the copy target data from the first storage device 200 when there is other data to be copied (“No” branch in step S106). If not (the process proceeds to step S102), otherwise (the branch of “Yes” in step S106), the reception determination process is repeated until the next copy command is received (the process proceeds to step S100).
The writing process using the algorithm B is the same process when the second storage device 300 is specified as the model 2. The difference is that there is no comparison process using the memory capacity information and no algorithm selection process. In the case of the model 2, the writing process using the algorithm B is executed in a fixed manner.

  Next, a data file stored in a cluster area in which all cluster numbers are discontinuous is read, and the read data file is written in a cluster area in which all cluster numbers in the second storage device 300 are discontinuous. Will be explained. Here, it is assumed that the second storage device 300 is identified as the model 1 and the memory capacity is determined to be less than the predetermined threshold. Therefore, the algorithm B is selected from the algorithms A and B, and the writing process is performed using the algorithm B. Hereinafter, specific operations will be described by omitting the description of overlapping portions as appropriate.

  Here, as shown in FIG. 7, the reading unit 12 reads data files stored in the cluster areas corresponding to the three cluster numbers of the cluster numbers “1Ah”, “1Ch”, and “1Eh”. In this case, the cluster continuity analysis unit 10 indicates that the above-described normal reading is possible for the information of the cluster numbers “1Ah”, “1Ch”, and “1Eh” and the areas of these cluster numbers. Information is passed to the reading unit 12 as an analysis result (step S202).

Accordingly, the reading unit 12 reads data for each cluster area from the cluster areas corresponding to the cluster numbers “1Ah”, “1Ch”, and “1Eh” based on the analysis result (step S204). In this case, reading of the data file is completed with three accesses (step S206).
On the other hand, the free cluster area detection unit 18 uses the second FAT in the state shown in FIG. 9 acquired from the second storage device 300 as a free cluster area in which the read data file (for 3 clusters) can be written. Free cluster areas corresponding to the numbers “0Dh”, “0Fh”, and “12h” are detected (step S320).

  The cluster continuity analysis unit 10 determines that all the free cluster areas corresponding to the detected cluster numbers “0Dh”, “0Fh”, and “12h” have discontinuous cluster numbers. The above-described information indicating that normal writing is possible with respect to the cluster area corresponding to the cluster number is generated as an analysis result, and this is passed to the writing unit 20 (step S322).

Based on the analysis result, the writing unit 20 performs data for each cluster area with respect to the free cluster areas corresponding to the cluster numbers “0Dh”, “0Fh”, and “12h” in the cluster area of the second storage device 300. Is written (step S324).
By this writing process, the second FAT of the second storage device 300 is updated to the state shown in FIG. That is, the FAT entry values “0Fh”, “12h”, and “EOF” are respectively set for the cluster numbers “0Dh”, “0Fh”, and “12h” that were previously free cluster areas.

  Next, an explanation will be given of the operation when a data file stored in a cluster area in which all cluster numbers are continuous is read and the read data file is written in a cluster area in which all cluster numbers of the second storage device 300 are continuous. To do. Here, it is assumed that the second storage device 300 is identified as model 1 and the memory capacity is determined to be equal to or greater than a predetermined threshold. Accordingly, the algorithm A is selected from the algorithms A and B, and the writing process is performed using the algorithm A. Hereinafter, specific operations will be described by omitting the description of overlapping portions as appropriate.

  Here, as shown in FIG. 7, the reading unit 12 reads data files stored in the cluster area corresponding to seven consecutive cluster numbers from the cluster numbers “20h” to “26h”. In this case, in the cluster continuity analysis unit 10, the information of the cluster numbers “20h” to “26h” (or the head address “20h” and Offset “00 to 0D”) and the areas of these cluster numbers are obtained. Information indicating that the optimum reading described above is possible is passed to the reading unit 12 as an analysis result (step S202).

  Therefore, based on the analysis result, the reading unit 12 stores data for each data amount that is the minimum access count in 8 clusters or less that is the maximum data transmission amount in the cluster area corresponding to the cluster numbers “20h” to “26h”. Is read (step S204). In this case, reading of the data file is completed with one access to the data for seven clusters “20h” to “26h” (step S206).

  On the other hand, the free cluster area detection unit 18 acquires the second FAT in the state shown in FIG. 10 from the second storage device 300 (step S310), and once with respect to the second storage device 300 based on the acquired second FAT. Since the maximum amount of data transfer that can be performed is 8 clusters, it corresponds to “40h” to “46h” in which all the cluster numbers are continuous as an empty cluster area where the read data file (7 clusters) can be written. An empty cluster area to be detected is detected (step S312). That is, since the second storage device 300 is a storage device having a relatively large memory capacity, the second storage device 300 executes a writing process in which the memory writing efficiency is more important than the memory usage efficiency. Therefore, as shown in FIG. 10, even if there is an empty cluster at a number lower than the cluster numbers “40h” to “46h”, a continuous cluster number and a discontinuous cluster number that are less than 7 as the number of data file clusters. Ignoring the free cluster area corresponding to, the continuous free cluster area having the cluster number of the data file (7 clusters) is detected from the cluster number ahead. In the algorithm A, the cluster number information of the detected empty cluster area is not transferred to the cluster continuity analysis unit 10 but directly to the writing unit 20.

  In the present embodiment, as described above, since the maximum data transfer amount that can be performed at one time for the second storage device 300 is 8 clusters, for example, 8 clusters such as data files for 32 clusters. When writing a data file having a larger number of clusters, an empty cluster area having consecutive cluster numbers may be detected every 8 clusters. In this case, for example, the cluster number information corresponding to the detected free cluster area may be passed to the cluster continuity analysis unit 10 to generate an analysis result.

Based on the information on the cluster number of the free cluster area from the free cluster area detection unit 18, the writing unit 20 creates a free cluster area corresponding to the cluster numbers “40h” to “46h” in the cluster area of the second storage device 300. On the other hand, the data file is written by one access (step S314).
By this writing process, the second FAT of the second storage device 300 is updated to the state shown in FIG. That is, the FAT entry values “41h”, “42h”, “43h”, “44h”, “45h”, “46h”, and the cluster numbers “40h” to “46h”, which were previously free cluster areas, and “EOF” is set respectively.

The writing process using the algorithm A is the same process when the second storage device 300 is specified as the model 3. The difference is that there is no comparison process using the memory capacity information and no algorithm selection process. In the case of the model 3, the writing process using the algorithm A is executed in a fixed manner.
As described above, according to the data access system 100 of the present embodiment, the second storage device 300 serving as a data file copy destination (write destination) is the model 1 and its memory capacity (total memory capacity or remaining memory capacity). Is less than a predetermined threshold (when the memory capacity is relatively low), or when the second storage device 300 is the model 2 (storage device with a relatively low memory capacity), data write processing efficiency and data It is possible to perform a writing process using the algorithm B in consideration of both usage efficiencies. As a result, the number of accesses in writing to free cluster areas with consecutive cluster numbers can be reduced, so that the data write processing efficiency can be improved without reducing the memory use efficiency.

  Further, according to the data access system 100 of the present embodiment, the second storage device 300 that is the copy destination (write destination) of the data file is the model 1 and its memory capacity (total memory capacity or remaining memory capacity). Is greater than or equal to a predetermined threshold (when the memory capacity is relatively large), or when the second storage device 300 is the model 3 (storage device with a relatively large memory capacity such as an HDD), the data writing process It is possible to perform a writing process using the algorithm A that emphasizes efficiency. As a result, a free cluster area having consecutive cluster numbers corresponding to the data amount of the data file or the maximum data transfer amount is detected, and optimal writing is performed on the free cluster area having the continuous cluster number. Since the number of accesses necessary for the data can be reduced to the maximum, the data write processing efficiency can be improved.

  In the above embodiment, the first storage device 200 and the second storage device 300 correspond to the storage medium of any one of Embodiments 1 to 6, and the cluster continuity analysis unit 10 performs the first continuity analysis of Embodiment 1. The reading unit 12 corresponds to the reading unit of mode 1, the model specifying unit 14 corresponds to the specifying unit of mode 3, and the memory capacity comparing unit 16 corresponds to the mode 2 and the second continuity analyzing unit. The free cluster area detecting unit 18 corresponds to the free small memory area detecting unit in the first or second mode, and the writing unit 20 corresponds to any one of the writing units in the first to third modes. To do.

In the above embodiment, the FAT type format file system has been described as an example. However, the present invention is not limited to this, and any system can be used as long as data access is performed in a similar format. May be applied.
In the above-described embodiment, the storage device such as HDD, SD card, CF (Compact Flash (registered trademark)) card, SMT media (registered trademark), OFM (Onboard Flash Memory) has been described as an example. However, the present invention may be applied to other storage devices such as MO, DVD, and FD.

  In the above embodiment, the specific operation has been described taking the FAT16 format as an example. However, the present invention is not limited to the FAT16, and the present invention is also applicable to other FAT type formats such as FAT12, FAT32, and VFAT. In addition, the same format can be applied to formats other than the FAT type.

It is a block diagram which shows the function structure of the data access system 100 which concerns on this invention. 2 is a hardware configuration diagram of the data access system 100. FIG. 4 is a flowchart showing a data file copying process in the data access system 100. 4 is a flowchart showing a data file read process in the data access system 100. 4 is a flowchart showing a data file writing process in the data access system 100. It is a figure which shows an example of the write-processing method (algorithm) with respect to the kind (model) and disk capacity of a storage device. 3 is a diagram illustrating an example of a first FAT in the first storage device 200. FIG. 3 is a diagram illustrating an example of a second FAT in the second storage device 300. FIG. It is a figure which shows an example of 2nd FAT after the write-in process to the cluster area | region where the continuous and discontinuous cluster area | region mixed. It is a figure which shows an example of 2nd FAT after the write-in process to the cluster area | region which becomes all discontinuous. It is a figure which shows an example of 2nd FAT after the write-in process to the cluster area | region which becomes all continuous.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Data access system, 200 ... 1st memory | storage device, 300 ... 2nd memory | storage device, 10 ... Cluster continuity analysis part, 12 ... Reading part, 14 ... Model specification part, 16 ... Memory capacity comparison part, 18 ... Empty cluster Area detection unit, 20 ... writing unit

Claims (6)

A data access system for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium Continuity analysis means;
Reading means for reading the data from the first storage medium based on the analysis result of the first continuity analysis means;
Based on the memory management information of the second storage medium and the information on the data amount of the data read by the reading means, the number of free small memory areas corresponding to the amount of data in the second storage medium is detected. Memory area detection means;
Second continuity analyzing means for analyzing the continuity of addresses in a number of free small memory areas corresponding to the amount of data detected by the free small memory area detecting means;
Writing means for writing the data to the second storage medium based on the analysis result of the second continuity analysis means;
The reading means, for a plurality of consecutive small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity that is the minimum number of accesses. For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
For the plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the writing means includes a plurality of free small memory areas for each data capacity corresponding to the minimum access count. For the number of free small memory areas corresponding to the amount of data, and the small free memory area of the address that is discontinuous with the address of the other free small memory areas. A data access system that writes the data for each size of a memory area. Comparing means for comparing a value relating to the memory capacity of the second storage medium with a predetermined threshold value,
When the value relating to the memory capacity of the second storage medium is equal to or greater than the predetermined threshold, the free small memory area detecting means continuously includes addresses corresponding to the data amount in the free small memory area of the second storage medium. It is designed to detect multiple free small memory areas,
When the value relating to the memory capacity of the storage medium is less than the predetermined threshold by the comparison, the writing means has a plurality of consecutive free addresses in the number of free small memory areas corresponding to the data amount. The data for the plurality of free small memory areas is written for each data capacity that is the minimum number of accesses to the small memory area, and other free small areas in the number of free small memory areas corresponding to the data amount are written. The data is written for each size of the small memory area in an empty small memory area that is discontinuous with the address of the memory area. 2. The data according to claim 1, wherein the data is written for each data capacity that is the minimum number of accesses to a plurality of free small memory areas. Access system. A specifying means for specifying the type of the second storage medium;
The writing means, when the type of the second storage medium specified by the specifying means is a specific type, based on the processing result of the comparison process, the first writing process or the second writing medium And the first writing process or the second writing process is fixedly executed according to the type when the process is selectively performed. The data access system according to claim 2. The storage medium has a FAT (File Allocation Table) type format in which the storage area is divided into sectors each having a predetermined memory size and is divided into clusters each composed of one or more sectors.
The memory management information is a FAT (File Allocation Table) composed of data storage state information of the cluster unit of the storage medium,
The data access system according to any one of claims 1 to 3, wherein the small memory area is a memory area of the cluster unit. A data access program for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size, based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium A continuity analysis step;
A reading step for reading the data from the first storage medium based on the analysis result of the first continuity analysis step;
An empty small memory area for detecting an empty small memory area corresponding to the data amount in the second storage medium based on the memory management information of the second storage medium and the data amount information of the data read in the reading step A detection step;
A second continuity analysis step for analyzing the continuity of addresses in the free small memory area detected in the free small memory area detection step;
A program for causing a computer to execute a process consisting of a writing step of writing the data to the second storage medium based on the analysis result of the second continuity analysis step;
In the reading step, for a plurality of continuous small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity corresponding to the minimum access count For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
In the writing step, for a plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the plurality of free small memories for each data capacity corresponding to the minimum access count. In addition to writing the data for the area, the number of free small memory areas corresponding to the amount of data corresponds to the free small memory area whose address is discontinuous with the addresses of other free small memory areas. A data access program for writing the data for each size of a small memory area. A data access method for performing data access to a storage medium having a memory area divided into a plurality of small memory areas of a predetermined size based on memory management information indicating a data storage state for each small memory area. There,
Based on the memory management information of the first storage medium and the information of data read from the first storage medium, a first analysis of the continuity of addresses in the small memory area where the data is stored in the first storage medium A continuity analysis step;
A reading step for reading the data from the first storage medium based on the analysis result of the first continuity analysis step;
An empty small memory area for detecting an empty small memory area corresponding to the data amount in the second storage medium based on the memory management information of the second storage medium and the data amount information of the data read in the reading step A detection step;
A second continuity analysis step for analyzing the continuity of addresses in the free small memory area detected in the free small memory area detection step;
A writing step of writing the data to the second storage medium based on the analysis result of the second continuity analysis step,
In the reading step, for a plurality of continuous small memory areas of the data storage address in the first storage medium, the data for the plurality of small memory areas for each data capacity corresponding to the minimum access count For the small memory area in which the data of the address that is discontinuous with the address of the other small memory area in the first storage medium is stored, the data for each size of the small memory area Read
In the writing step, for a plurality of free small memory areas having consecutive addresses in the number of free small memory areas corresponding to the amount of data, the plurality of free small memories for each data capacity corresponding to the minimum access count. In addition to writing the data for the area, the number of free small memory areas corresponding to the amount of data corresponds to the free small memory area whose address is discontinuous with the addresses of other free small memory areas. A data access method comprising writing the data for each size of a small memory area.

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