JP2005321940A - Electronic information management system, storage medium, electronic information management method, and electronic information management program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable high-speed access to electronic information stored in a storage medium. <P>SOLUTION: In a storage medium recording data for every predetermined cluster, when successive access to electronic information is performed for every cluster by use of link information for registering information specifying a cluster that is a link destination from each cluster, the access to electronic information is performed by use of an index database registering information for specifying a cluster registering each data at predetermined intervals from the head data of the electronic information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic information management system, a storage medium, an electronic information management method, and an electronic information management program for retrieving electronic information stored in a storage device.

  Currently, access control to electronic information stored in a file management system called a file allocation table (FAT) is performed on a hard disk or an optical disk used as a storage device of a computer.

  The memory area of the storage medium is divided into storage units called clusters, and a cluster number is assigned to each cluster. As shown in FIG. 4, the recording medium includes file entry information indicating the cluster number in which the leading data of each electronic information stored in the storage medium is stored, and each cluster as shown in FIG. The link information of the FAT in which the cluster number as the link destination from the cluster is registered is registered. When accessing the electronic information stored in the storage medium, the cluster number at the head of the memory area storing the electronic information to be accessed is read from the file entry information, and the cluster number is used as the file pointer. The stored data is accessed by seeking to the cluster specified by the cluster number. Based on the FAT link information, the cluster number as the link destination from the cluster is sequentially read out as a new file pointer, and stored by seeking to the cluster to which the cluster number as the link destination is assigned. Access data.

JP 2004-30232 A

  In the conventional FAT link information, the cluster number that is the link destination for each cluster is registered. Therefore, sufficient access is required when accessing data stored in the cluster located behind the current file pointer. Speed can be realized.

  However, since no link information ahead of the currently accessed cluster is registered in the FAT link information, data stored in a cluster located ahead of the current file pointer is accessed. In this case, it is necessary to retrace the link from the cluster in which the top data of the electronic information to be accessed is stored.

  For example, in the FAT link information shown in FIG. 5, when the current file pointer is set to the cluster number “32768”, the access destination is changed to the cluster specified by the cluster number “25605”. It is necessary to seek by following the link destination in order from the cluster of cluster number “2” of 0 to the cluster of cluster number “25605”.

  As described above, in order to access data stored in a cluster that is not linked from the cluster that is currently accessed in the FAT link information, a number of clusters are traced before the target cluster is accessed. As a result, it was impossible to obtain sufficient access speed to electronic information.

  In particular, when accessing electronic information having a huge file size of several hundred megabytes or more like a movie file, the seek time to the front becomes longer and the access speed becomes extremely slow as the file pointer moves backward. .

  The present invention provides an electronic information management system, a storage medium, an electronic information management method, and an electronic information management program that enable high-speed access to electronic information stored in a storage medium in view of the above-described problems of the prior art. Objective.

  The present invention sequentially accesses electronic information for each cluster by using link information in which information for specifying a cluster as a link destination from each cluster is registered on a storage medium in which data is recorded for each predetermined cluster. In this case, the electronic information is accessed using an index database in which information for identifying a cluster in which each data is recorded is registered at predetermined intervals from the top data of the electronic information to be accessed. .

  Specifically, the electronic information management program causes the computer to store link information in which information for identifying a cluster that is a link destination from each cluster is registered on a storage medium in which data is recorded for each predetermined cluster. An electronic information management system for sequentially accessing electronic information for each cluster using an index database in which information for identifying a cluster in which each data is recorded at a predetermined interval from the top data of the electronic information is used This can be realized by functioning as an electronic information management system for accessing electronic information.

  In particular, when link information such as a conventional file allocation table (FAT) is used, a link is provided from a cluster ahead of the currently accessed cluster, that is, the currently accessed cluster. It is preferable to access using the index database when accessing a cluster that has not been performed.

  Further, it is preferable that the predetermined interval is determined based on at least one of a size of electronic information and a size of a cluster.

  Further, another aspect of the present invention is a storage medium in which data is recorded for each predetermined cluster, in which link information in which information specifying a cluster to be linked from each cluster is registered, and an access target An index database in which information for specifying a cluster in which each data is recorded is recorded at predetermined intervals from the first data of the electronic information.

  According to the present invention, electronic information stored in a storage device can be accessed at high speed. This is particularly effective when accessing electronic information having a large data size such as a moving image file.

  As shown in FIG. 1, an electronic information management system according to an embodiment of the present invention includes a disk 10, a read head 12, a recording head 14, a head drive circuit 16, a decoder 18, an encoder 20, a semiconductor memory 22, and a semiconductor memory control circuit. 24, a spindle motor 26, a motor drive circuit 28, and a main processing circuit 30.

  In this embodiment, a hard disk device is described as an example of an electronic information management system. However, the present invention is not limited to this, and any electronic device that can use the access method in this embodiment can be applied. .

  The electronic information management system reads data from the recording medium according to the flowchart shown in FIG. The following steps are realized by executing, in the main processing circuit 30, an electronic information management program stored in the semiconductor memory 22 on an operating system (OS) or the like.

  In step S10, file entry information and a file allocation table (FAT) are read from the disk 10 which is a recording medium. When the electronic information needs to be read, the main processing circuit 30 transmits a control signal to the motor drive circuit 28 to control the spindle motor 26 and rotate the disk 10 by the spindle motor 26. At the same time, a control signal is transmitted to the head drive circuit 16 to move the read head 12 to the file entry information on the disk 10 and the FAT recording position, and read the contents.

  In step S12, the data format of the read information is converted. The read information is sent to the decoder 18, and after processing such as data format conversion is performed by the decoder 18, it is sent to the semiconductor memory control circuit 24 and stored in the semiconductor memory 22.

  In step S14, the read information is analyzed. The read information is sent from the semiconductor memory control circuit 24 to the main processing circuit 30, and the contents are analyzed in the main processing circuit 30. The main processing circuit 30 extracts the cluster number in which the top data of the file to be read is recorded from the FAT file entry information and designates it as a file pointer. For example, if the file name to be read is “DCP — 0001.mov”, in the example of the file entry information in FIG. 4, the cluster number “2” in which the first data is recorded becomes the value of the file pointer. .

  In step S16, data is actually read. The main processing circuit 30 transmits a control signal to the head driving circuit 16, causes the read head 12 to seek to the position of the cluster designated by the file pointer, and reads data from the cluster.

  In step S18, the read data is processed. The read data is sent to the decoder 18, and after processing such as data format conversion is performed by the decoder 18, the data is transmitted to the semiconductor memory control circuit 24. Then, if necessary, data is transmitted to the main processing circuit 30 to process the data, and the semiconductor memory 22 stores and holds the data.

  In step S20, the index database is registered. The index database is formed for each file to be accessed and held in the semiconductor memory 22. In the index database, a cluster number in which each data is stored every predetermined interval N from the top data of each file is registered.

  For example, when the predetermined interval N is 100 clusters, as shown in FIG. 3, the cluster number “1” in which the top data is stored for the file “DCP — 0001.mov” to be read. Each time data for 100 clusters is read from the cluster specified by 2 ″, the cluster number in which the data is stored is registered in the index database. That is, if the data capacity recorded in one cluster is 8 kbytes, the cluster number storing the data is registered every 800 kbytes (100 clusters) from the top of the file “DCP — 0001.mov”. It becomes.

  More specifically, a counter for cyclically counting from 1 to 100 is provided, and the counter value is incremented by 1 each time data is read from the disk 10 in step S16, so that the counter value becomes 100. The cluster number where the data read at the time was stored is registered in the index database.

  In step S22, when there is an instruction for rewinding or fast-forwarding during moving image reproduction and only data from the rewinding destination or fast-forwarding destination cluster is actually required, the processing in steps S16 to S20 is omitted. May be.

  In step S22, data to be read next is specified. The main processing circuit 30 checks whether or not an instruction such as a rewinding operation at the time of moving image reproduction is input from a user interface (not shown). When an instruction such as a rewinding operation is not input, data continuous with the data read in step S16 is set as a reading target. Then, the process proceeds to step S24. On the other hand, if an instruction is input, data positioned in front of the data read in step S16 is a reading target. At this time, it is specified in which cluster the data to be read is stored from the top data of the file. Then, the process proceeds to step S26. Note that the same processing can be performed when an instruction such as a fast-forward operation during video reproduction is input. However, in the case of fast-forwarding, it is specified in which cluster the data to be read is stored from the top data of the file, and if the cluster is in an area that has already been read in the past, go to step S26. If the process is shifted to an area that has not yet been read, the process shifts to step S24.

  In step S24, it is determined whether or not the link information of the next data access destination is included in the FAT link information read in step S10. The link information of the FAT stored in the semiconductor memory 22 is read, and it is determined whether or not the link destination information associated with the cluster to be read next is included. If the link information of the FAT stored in the semiconductor memory 22 includes link destination information, the process proceeds to step S30. If the link destination information is not included, the process proceeds to step S28. Transition.

  In step S28, the FAT link information including the link destination information associated with the cluster to be read next is read from the recording medium. The reading can be performed in the same manner as in step S10, and the data format is converted and stored in the semiconductor memory 22 in the same manner as in step S12.

  In step S30, the cluster number in which the next data is recorded is extracted based on the FAT information. The main processing circuit 30 specifies a cluster number in which data to be read next is recorded from the FAT link information stored in the semiconductor memory 22. For example, in the example of the link information in FIG. 5, the cluster number of the second cluster from the top of the file is “3”. When the identified cluster number is designated as the value of the file pointer, the process returns to step S16 to read the data.

  On the other hand, in step S26, the cluster number for accessing the cluster storing the data to be read is obtained. The main processing circuit 30 is configured to access the data to be read from the index database based on the information indicating in what cluster the data to be read is stored from the top data of the file. To decide.

  For example, taking the index database shown in FIG. 3 as an example, if data stored in the 23856th cluster from the top of the file “DCP — 0001.mov” is to be read, 23856/100 = 238 ( The cluster number registered in association with the (truncated) th index is designated as the value of the file pointer.

  When the cluster number of the cluster to be accessed is obtained, the process proceeds to step S24.

  By using the index database in this way, it is possible to specify a cluster number suitable for linking to the data newly read in step S22.

  When data stored in a cluster that is not linked from the currently accessed cluster is changed to a read target due to input such as rewind playback of a video, the conventional access method that uses only the FAT link information There was no other way but to access the data to be read by following the links in order from the top of the file. On the other hand, according to the present embodiment, by referring to the index database, a cluster having a closer link to the data to be read is designated as a file pointer, and the number of accesses is reduced by following the link from the cluster. Can be accessed. In this method, the maximum number of accesses until reaching the target data is N (index database interval) -1 times. In addition, when an instruction for rewinding a movie is instructed, the link destination is not traced from the top data of the file as in the past, but only the link destination is traced from the cluster specified by the index database. Even when all the included link information cannot be cached in the semiconductor memory 22 at a time, the number of times of re-reading the FAT link information when following the link can be reduced.

  In the present embodiment, the index database registration interval N is set to 100 clusters. However, the present invention is not limited to this. As the registration interval N is reduced, the number of links to be traced decreases, so that access can be speeded up. However, since the data capacity of the index database increases, the amount of memory used increases. Therefore, it is preferable to determine the registration interval N based on the relationship between the file size and the cluster size. For example, it is preferable to determine the registration interval N based on the ratio between the file size and the cluster size.

  Further, when accessing a storage medium when playing back a moving image or the like, access is often made from the same data many times. Accordingly, when access is made based on the registration contents of the index database by an instruction such as a rewinding operation, it is also preferable to update the registration contents of the index database with the cluster number in which the data designated as the rewind destination is recorded. It is. As a result, it is possible to access the data once designated as the rewinding destination at a higher speed when the rewinding instruction is given again.

  In this embodiment, the recording medium is a disc. However, any device that accesses data using a FAT or similar format is applicable to the present invention.

  In this embodiment, the index database is registered together with the reading process of data from the disc. However, the index database created in advance together with the FAT information is recorded on the recording medium and recorded on the recording medium. It is also preferable to access by referring to the index database. Such a form is suitable for speeding up access in a rewrite-inhibited recording medium such as a CD-ROM in which a large amount of electronic information such as a moving image is recorded.

It is a block diagram which shows the structure of the electronic information management system in embodiment of this invention. It is a figure which shows the flowchart of the electronic information management method in embodiment of this invention. It is a figure which shows the example of registration of the index database in embodiment of this invention. It is a figure which shows the example of the file entry information of a file allocation table (FAT). It is a figure which shows the example of the link information of a file allocation table (FAT).

Explanation of symbols

  10 disc, 12 read head, 14 recording head, 16 head drive circuit, 18 decoder, 20 encoder, 22 semiconductor memory, 24 semiconductor memory control circuit, 26 spindle motor, 28 motor drive circuit, 30 main processing circuit.

Claims (10)

For a storage medium in which data is recorded for each given cluster,
An electronic information management system for sequentially accessing electronic information for each cluster using link information in which information for identifying a cluster to be linked from each cluster is registered,
An electronic information management system for accessing electronic information by using an index database in which information for identifying a cluster in which each data is recorded at a predetermined interval from the top data of the electronic information to be accessed is registered. . The electronic information management system according to claim 1,
An electronic information management system that performs access using the index database when accessing an unlinked cluster from a currently accessed cluster. In the electronic information management system according to claim 1 or 2,
The electronic information management system according to claim 1, wherein the predetermined interval is determined based on at least one of a size of electronic information and a size of clusters. A storage medium in which data is recorded for each predetermined cluster,
Link information in which information identifying the cluster to be linked from each cluster is registered,
An index database that registers information for identifying clusters in which each data is recorded at predetermined intervals from the top data of electronic information to be accessed;
A storage medium on which is recorded. For a storage medium in which data is recorded for each given cluster,
An electronic information management method for sequentially accessing electronic information for each cluster using link information in which information specifying a cluster to be linked from each cluster is registered,
An electronic information management method for accessing electronic information by using an index database in which information for specifying a cluster in which each data is recorded at predetermined intervals from the top data of the electronic information to be accessed is registered. . The electronic information management method according to claim 5,
An electronic information management method comprising: accessing an unlinked cluster from a currently accessed cluster using the index database. The electronic information management method according to claim 5 or 6,
The electronic information management method, wherein the predetermined interval is determined based on at least one of a size of electronic information and a size of a cluster. Computer
Electronic information management that sequentially accesses electronic information for each cluster using link information in which information for identifying a cluster that is a link destination from each cluster is registered to a storage medium in which data is recorded for each predetermined cluster A system,
To function as an electronic information management system for accessing electronic information using an index database in which information for identifying a cluster in which each data is recorded at a predetermined interval from the first data of electronic information to be accessed is registered. A featured electronic information management program. The electronic information management program according to claim 8,
The computer,
An electronic information management program that functions as an electronic information management system that uses the index database to access an unlinked cluster from a currently accessed cluster. The electronic information management program according to claim 8 or 9,
The electronic information management program, wherein the predetermined interval is determined based on at least one of a size of electronic information and a size of a cluster.

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