JP6506050B2 - Terminal electronics - Google Patents

Description

The present invention relates to a terminal electronic device , and more particularly to a terminal electronic device provided with a cache file system that can effectively use local storage.

  A distributed file system has been proposed in which a plurality of terminal electronic devices share the file of the host device (server) via the network, but the terminal electronic device has its own storage device (local storage) Access to files is speeded up by keeping it in). Therefore, the terminal electronic device is required to have a sufficient storage capacity for the file to be taken.

  If a game machine is taken as an example of a terminal electronic device, recently, the game program executed on the game machine has become more sophisticated and complicated, and while the amount of programs increases, the storage capacity required for the local storage tends to increase. It is in.

  For example, Patent Document 1 discloses a configuration for securing a storage capacity by purging a file having a low priority or a file having an old reference time when the storage capacity in the terminal is insufficient.

  In addition, in the terminal electronic device, in order to keep the file updated, the host device needs to be accessed periodically to update the file, but the cost increases as the file to be updated becomes larger.

  Patent Document 2 discloses a system in which a server and a terminal interact with each other to exchange information on change points of a file in order to update the file efficiently.

JP-A-7-182220 Patent No. 4794143

  As described above, in the distributed file system, the storage capacity required of the terminal electronic device tends to increase, but until now, when the storage capacity is increased according to the request or when the storage capacity is insufficient. The only measures taken were to purge some files. In addition, when updating files, an inefficient method has been adopted such that the server and the terminal repeatedly interact with each other.

The present invention has been made to solve the above-mentioned problems, and it is possible to cope with an increase in required storage capacity and to provide a terminal electronic device provided with a cache file system capable of efficiently updating files. Intended to be provided.

A first aspect of the terminal electronic device according to the present invention is a terminal electronic device having a cache file system for downloading file data in a host device via a network and managing data cached in an internal storage device. The cache file system includes a management table which is provided in the storage device and manages chain information indicating the connection between minimum management units constituting the file, and the management table is the storage device of the storage device. The storage device has the number of rows capable of managing the storage capacity exceeding the storage capacity, and the rows for exceeding the storage capacity of the storage device are allocated to the management of the data of the file in the host device, to the storage device It also manages the data of the file in the host device along with the cached data.

In a second aspect of the terminal electronic device according to the present invention, the cache file system downloads the data of the file for each of the minimum management units, and the management table includes the host device for each of the minimum management units. Managing the data of the file and the data cached in the storage device.

In a third aspect of the terminal electronic device according to the present invention, the cache file system sequentially downloads the data of the file in the host device.

In a fourth aspect of the terminal electronic device according to the present invention, the management table is divided into a management area of in-storage data and a management area of in-host data, and the data cached in the storage is: The data in the file in the host device managed in the management area of the data in the storage device is managed in the management area of the data in the host device.

A fifth aspect of the terminal electronic device according to the present invention is that the cache file system deletes a line for managing the data cached in the storage device of the management area of the storage device data of the management table. To delete the data cached in the storage device.

According to a sixth aspect of the terminal electronic device of the present invention, the cache file system deletes, of the data cached in the storage device, data that has been used for the longest time.

According to a seventh aspect of the terminal electronic device of the present invention, the cache file system deletes, of the data cached in the storage device, data whose number of times of use is lower than a specified value.

In an eighth aspect of the terminal electronic device according to the present invention, in the management area of the data in the storage device, the management table includes a number assigned to each of the minimum management units, and a number subsequent to the minimum management unit. The number and the number are recorded in one line, and in the management area of the data in the host device, when the minimum management unit is continuous, the continuous number of the minimum management unit in the first line of the minimum management unit Is described.

In a ninth aspect of the terminal electronic device according to the present invention, when there is a change in the file, the host device creates an update list indicating the contents of the change, adds a revision number and manages it, and the cache file The system confirms the revision number managed by the host device when accessing the host device, and if the revision number has been changed, refers to the update list to change the management table Do.

In a tenth aspect of the terminal electronic device according to the present invention, in the cache file system, when the file is updated, all data of the corresponding file or data of the updated portion is a management area of the in-host device data Change the management table as in

In an eleventh aspect of the terminal electronic device according to the present invention, when the cache file system adds the file, the management table is set so that all data of the file is in the management area of the data in the host device. Change

In a twelfth aspect of the terminal electronic device according to the present invention, the cache file system changes the management table so as to delete all data of the file when the file is deleted.

According to the terminal electronic device according to the present invention, obtained with it corresponding to the increase in the storage capacity required for the storage device of the terminal the electronic device, the terminal electronic device including the efficient file cache file systems can be updated Be

It is a block diagram which shows the structure of the terminal electronic device provided with the cache file system which concerns on this invention. It is a figure which shows an empty state of local storage. FIG. 5 is a diagram showing an initial FAT entry and directory entry created by a terminal electronic device. It is a figure explaining reading of the file from a server. FIG. 6 is a diagram showing an example of writing of a FAT entry when downloading sequentially from a server, and an example of data to be written in a data area. It is a figure explaining the example of update of a file, addition, and deletion. It is a figure explaining the example of update of a file, addition, and deletion. It is a figure explaining the example of update of a file, addition, and deletion. It is a figure explaining the example of update of a file, addition, and deletion. It is a figure explaining the modification of writing of a FAT entry. It is a figure explaining the modification of writing of a FAT entry. It is a figure explaining the conventional FAT entry.

<Introduction>
Prior to the description of the invention, a conventional file allocation table (FAT) file system will be described. In the FAT file system, chain information of actual data stored in the storage device is stored in the management table.

  That is, although the file is configured with the cluster as the minimum management unit, the physical positions of the cluster in the storage device are not necessarily continuous. Therefore, the FAT manages information (chain information) on how each cluster is connected and configures one file, and each entry of the FAT corresponds to one cluster. The file name of the file and the cluster number of the first cluster of the file are recorded in the directory entry.

  An example of the FAT entry and the directory entry will be described below with reference to FIG.

  In FIG. 12, file a. The case where bin starts from the cluster number 1000 is shown, and in the management table (FAT entry), chain information on clusters with cluster number 1000 or less is stored.

  That is, in the FAT entry, the cluster number where data is stored in the storage device and the value of the cluster number of the next succeeding cluster are recorded.

  Files shown in FIG. The bin data is stored in the storage device in the order of cluster numbers 1000, 1001, 1002, 2000, 2001, 2002, 3000, 3001, 3002.

  In other words, the cluster number of the cluster following cluster number 1000 is 1001, the cluster number of the cluster following cluster number 1001 is 1002, and the cluster number of the cluster following cluster of cluster number 1002 is 2000. There is. In FIG. 12, the connections of the clusters are represented by arrows for the sake of convenience.

  It is also shown that the cluster number of the cluster following cluster number 2000 is 2001, the cluster number of the cluster following cluster number 2001 is 2002, and the cluster number of the cluster following cluster of cluster number 2002 is 3000. There is.

  Furthermore, the cluster number of the cluster following the cluster number 3000 is 3001, the cluster number of the cluster following the cluster number 3001 is 3002, and the cluster of the cluster number 3000 is shown to be EOC (End Of Cluster chain) There is.

  Usually, this table has an area enough to manage the storage capacity of the local storage, for example, if the local storage is 10000 clusters, it is a table of 10000 rows (elements) or more.

  Thus, the FAT file system prepares a table capable of managing the storage capacity of the local storage, but as described above, the storage capacity required for the local storage tends to increase, but Accordingly, it is difficult in terms of cost to increase the storage capacity of the local storage, and there is a physical limit to the expansion of the storage capacity in the terminal electronic device even if the cost is ignored.

  Therefore, according to the present invention, even if there is no local storage that can store all the data necessary for program execution etc., the management table for managing the chain information is managed beyond the storage capacity of the local storage. The management table in the local storage can be managed by providing the possible number of lines (number of elements) and allocating the lines for the amount exceeding the storage capacity of the local storage to the management of data of files in the host device (server). It also manages data of files in it. Then, data necessary for program execution and the like are downloaded sequentially from the server via the network and provided with a cache file system.

Embodiment
An embodiment of a cache file system according to the present invention will be described below with reference to FIGS.

<Device configuration>
FIG. 1 is a block diagram showing the configuration of a terminal electronic device EQ provided with a cache file system according to the present invention. As shown in FIG. 1, the terminal electronic device EQ is an electronic device connected to a network NW such as the Internet. The network NW is not limited to the Internet, and includes a Local Area Network (LAN), a Wide Area Network (WAN), a public network, and the like.

  Also connected to the network NW is a server SV serving as a host device of the terminal electronic device EQ, and the terminal electronic device EQ accesses the server SV via the network NW to set a file set from the storage device MR in the server SV. to download. The server SV also shares files with a plurality of terminal electronic devices EQ.

  The terminal electronic equipment EQ caches data of the file set downloaded from the server SV in the data area 12 in the local storage 10, but when downloading, the data of the file in the file set is not downloaded in file units. Download and cache only the necessary data in cluster units. In order to perform such processing, the local storage 10 is managed by the cache file system 20 according to the present invention.

  The cache file system 20 includes, for example, a central processing unit (CPU), a random access memory (RAM), and a read only memory (ROM) (not shown), and reads a cache file program stored in the ROM into the RAM. This is realized by the CPU executing the program. Further, the local storage 10 is configured by a storage device such as a flash memory. The CPU may have a function of executing an application program of the terminal electronic device EQ.

<File system operation>
The operation of the cache file system will be described below. Although the following description is given taking the case of application to the FAT file system as an example, the application of the present invention is not limited to the FAT file system.

<Initial state>
In the initial state, the local storage is empty, or only the management information of all the files in the server SV is stored, and all the actual data exists only in the server. In FIG. 2, the local storage 10 (FIG. 1) is shown empty, and nothing is written in either the directory entry in the management area 11 or the FAT entry (management table). This indicates that the data of all files are in the server SV.

  Here, as a characteristic configuration of the cache file system according to the present invention, the FAT entry has the number of manageable lines (number of elements) beyond the storage capacity of the local storage, and the FAT entry is By dividing the management area and the management area of data in the server, the FAT entry is used not only for management of data in the local storage but also for management of data in the server. Therefore, in the FA entry of FIG. 2, the management area of the data in the local storage is provided on the upper side, and the management area of the data in the server is provided on the lower side.

  In addition, as shown in FIG. 2, the server SV includes files a. bin, file b. bin and file c. bin is stored.

  When the terminal electronic device EQ accesses the server SV, it downloads the file name, file size, revision number, etc. from the server SV, and based on them, creates the initial stage FAT entry and directory entry, and the initial state local storage Write to 10 The revision number is changed when there is a change in the file and file configuration in the server, and the terminal electronic device EQ can detect that the file and the file configuration have been changed by changing the revision number.

  FIG. 3 shows an initial FAT entry and directory entry created by the terminal electronics EQ. As shown in FIG. 3, the directory entry contains files a. bin, file b. bin and file c. The cluster numbers 11000, 12000 and 13000 of the respective leading clusters of bin are written.

  Also, the FAT entry contains files a. bin, file b. bin and file c. The cluster number of the cluster that constitutes each bin and the value of the cluster number of the subsequent cluster are written. These are written in the management area of data in the server, and nothing is written in the management area of data in the local storage. This is because the file is not downloaded at the time of creation of the FAT entry in the initial stage, and the data of all the files are still in the server SV.

  Therefore, the FAT entry only manages data in the server. For example, nine clusters from cluster number 11000 to cluster number 11008 are files a. It is a cluster that configures bin, and the cluster with cluster number 11008 is EOC.

  In the FAT entry of FIG. 3, for example, the value for the cluster number 11000 is set to 11001, and it is understood that the cluster number of the cluster following the cluster of the cluster number 11000 is 11001. The connection of clusters up to cluster number 11008 is similarly shown below. In FIG. 3, the connection of each cluster is represented by an arrow for convenience.

  Also, nine clusters from cluster number 12000 to cluster number 12008 are files b. 9 clusters from cluster number 13000 to cluster number 13008, which are clusters configuring bin, are files c. It is a cluster that configures bin.

  Here, for example, file a. It is the terminal electronic device EQ that the clusters constituting the bin are from the cluster number 11000 to the cluster number 11008 are the files downloaded from the server SV by the terminal electronic device EQ a. This is the result of calculating the number of clusters based on the file size of bin and assigning the number to each cluster, and this cluster number does not correspond to the cluster number in the server SV. This is the same for the cluster number of the first cluster written in the directory entry.

  As described above, the configuration has been described in which the terminal electronic device EQ determines the cluster number and the like based on the file size downloaded from the server SV and creates the FAT entry in the initial stage. The number may be downloaded and written to the FAT entry. Also in this case, since the data of all the files are in the server SV, the result is a FAT entry similar to FIG.

<Read file from server>
The terminal electronic device EQ accesses the server SV as shown in FIG. 4 when the FAT entry in the initial stage is obtained. Thereafter, the file set is downloaded from the storage device MR in the server SV. At this time, it is not the entire file that is downloaded but only the portion that is currently required to be downloaded.

  That is, as described above, the file stored in the server SV is being enlarged, but there may be cases where only a part of the file is actually required. For example, in the case of a file of a game program, unnecessary data changes as the game progresses, and necessary data (stage data, character data, movie data) in one stage becomes unnecessary in the next stage. In other words, unnecessary data in the next stage may be downloaded, for example, immediately before the end of the current stage, and need not be downloaded in the current stage.

  As described above, by downloading only the necessary part sequentially when downloading the file from the server SV, the amount of data to be downloaded is reduced, the time required for file acquisition is shortened, and the minimum necessary data is obtained. Are stored in the local storage 10, the local storage 10 can be used effectively. Also, the load on the server SV can be reduced. That is, although a plurality of terminal electronic devices EQ may simultaneously access the server SV, even in such a case, if the amount of data downloaded by each terminal electronic device EQ is small, the server SV is overloaded. It is possible to suppress the server SV from becoming dysfunctional.

  FIG. 5 shows an example of writing of a FAT entry in the case of sequential downloading, and an example of data to be written in the data area 12.

  As shown in FIG. 5, the directory entry contains files a. bin, file b. bin and file c. The cluster numbers 1000, 2000 and 3000 of the first cluster of each bin are written.

  Also, in the management area of data in the local storage of the FAT entry, files a. bin, file b. bin and file c. The cluster number of the necessary part of the cluster in the bin and the value of the cluster number of the subsequent cluster are written.

  In the example of FIG. Of the nine clusters constituting the bin, six clusters are downloaded and exist in the local storage 10, and the remaining three clusters are illustrated as being present in the server. This is the file b. bin and file c. The same is true for bin.

  That is, data corresponding to cluster number 1000 to cluster number 1002 exist in the local storage 10, the value for cluster number 1002 is set to 11003, and the cluster number of the cluster following the cluster of cluster number 11002 is 11003. The data corresponding to the cluster number 11003 exists in the server SV, and the data corresponding to the cluster numbers 11003 to 11005 exist in the server SV. The value for the cluster number 11005 is 1500, and the cluster number of the cluster following the cluster with the cluster number 11005 is 1500.

  Data corresponding to the cluster number 1500 exists in the local storage 10, data corresponding to cluster numbers 1500 to 1502 exist in the local storage 10, and a cluster with the cluster number 1502 is EOC.

  Thus, by managing data in cluster units, caching in cluster units can be realized. That is, the data area in FIG. 5 shows a state in which data downloaded from the server is cached in cluster units. For example, as data corresponding to cluster number 1000 to cluster number 1002, file a. The data of the first cluster to the third cluster of bin are stored, and as data corresponding to cluster number 1500 to cluster number 1502, file a. Data from the seventh cluster to the ninth cluster of bin are stored.

  In the above, the file a. An example is shown in which six clusters are downloaded and present in the local storage 10 out of the nine clusters constituting the bin, but data not stored in the local storage 10 are downloaded from the server SV.

  Applications executed on the terminal electronics EQ, eg from the game a. If access occurs to the first three clusters of bin, the cache file system reads the data from the local storage and gives it to the application, but then the file a. When access to data from the fourth cluster to the sixth cluster of bin occurs, the cache file system downloads data of the corresponding cluster from the server based on the writing of the FAT entry.

  For example, when an access occurs to data corresponding to cluster number 11003 to cluster number 11005, the cache file system determines from the writing of the FAT entry that they exist in the server SV, File a. Request data from 4th cluster to 6th cluster of bin. The requested server SV transmits the requested data to the terminal electronic equipment EQ, and the cache file system provides the application with the data received from the server SV. In this case, the received data may be stored (cached) in the local storage 10 once.

  When the local storage 10 runs out of space, the newly downloaded data can be cached by deleting the data in the local storage.

<Updating, Adding, and Deleting Files in the Server>
If there is a change in the file and file configuration in the server SV, it is necessary to reflect it in the cache file system in the terminal electronic device EQ. A revision number is set to the file set stored in the server SV, and the revision number is updated each time the file and file configuration in the server SV are changed. Also, for each revision, an update list is created to indicate which files have been updated, added, or deleted.

  On the other hand, the terminal electronic device EQ also manages the revision number, and the terminal electronic device EQ manages the revision number of the file set managed by the server SV when accessing the server SV and the revision managed by the local storage 10 Compare with the number. If the revision numbers are different, refer to the file update list and do the following:

<Operation on updated file>
Delete all caches of corresponding files in local storage, update FAT entry to indicate that all data of the corresponding file is in the server, or indicate that updated data is in the server Update to In the latter case, deletion of the cache of the local storage is only the cache corresponding to the updated part.

  At the time of file update, update information may be managed not on a file basis but on a cluster basis. A difference is taken between the pre-update file and the post-update file, and a FAT entry is created to indicate that only the cluster with the difference has data in the server. When the number of update locations is small, update is performed in cluster units, but when the number of update locations is large, update in file units and update in cluster units may be mixed, such as updating in the entire file. This enables more efficient caching.

<Operation on added file>
Add the file to the management information of the local storage. It also creates a FAT entry to indicate that all data in the file is in the server.

<Operation on deleted file>
Delete the corresponding file from the management information of the local storage.

  These operations make it possible to realize a transparent file system between the server SV and the local storage 10. As described above, making the revision numbers the same for the server SV and the local storage 10 is called “synchronization”.

  The minimum necessary update content is written in the file update list in the server SV. Such an update list may be created each time a revision is updated, or the updated contents of all the revisions may be written. Therefore, regardless of the revision number of the local storage 10, it is possible to synchronize to the latest revision number.

  Hereinafter, specific examples of file update, addition, and deletion will be described with reference to FIGS. After writing the FAT entry as shown in FIG. 5, there is a change in the file and file configuration in the server SV as shown in FIG. 6, and the revision number of the file set is updated from r1 to r2 I assume.

  In the file set of revision number r2, file c. bin is deleted and file d. There is a file configuration change that bin is added, and file b. As bin is generally changed, file a. The third cluster of bin has been changed. These changes are listed in the update list.

  FIG. 7 shows directory entries and FAT entries created based on the file set of revision number r2 downloaded from the server SV via the network NW and the update list.

  As shown in FIG. 7, the directory entry contains files a. bin, file b. bin and file d. The cluster numbers 1000, 15000 and 16000 of the respective leading clusters of bin are written.

  Also, in the management area of data in the local storage of the FAT entry, files a. The cluster number of the necessary part of the cluster in the bin and the value of the cluster number of the subsequent cluster are written.

  In the example of FIG. Of the nine clusters constituting the bin, five clusters are downloaded and exist in the local storage 10, and the remaining four clusters are illustrated in the server SV. File a. The third cluster of bin is present in the server SV in place of the cluster number 14000.

  That is, data corresponding to cluster number 1000 and cluster number 1001 is present in local storage 10, the value for cluster number 1001 is 14000, and data corresponding to cluster number 14000 is present in server SV.

  The cluster number of the cluster following the cluster of cluster number 14000 is 11003, the data corresponding to cluster number 11003 exists in server SV, and the data corresponding to cluster number 11003 to cluster number 11005 exist in server SV There is. The value for the cluster number 11005 is 1500, and the cluster number of the cluster following the cluster with the cluster number 11005 is 1500.

  Further, data corresponding to the cluster number 1500 exists in the local storage 10, data corresponding to the cluster numbers 1500 to 1502 exist in the local storage 10, and the cluster with the cluster number 1502 is EOC.

  File b. bin is changed from 9 clusters to 3 clusters as a whole is changed, and all 3 clusters exist in the server SV, and are written in the management area of the data in the server of the FAT entry There is.

  That is, data corresponding to cluster number 15000 to cluster number 15002 exist in the server SV. The value for the cluster number 15000 is 15001, and the cluster number of the cluster following the cluster with the cluster number 15000 is 15001. Further, the value for the cluster number 15001 is 15002, the cluster number of the cluster following the cluster with the cluster number 15001 is 15002, and the cluster with the cluster number 15002 is EOC.

  File d. The bin has a one-cluster configuration, and the one cluster exists in the server SV, and is written in the management area of the data in the server of the FAT entry.

  That is, data corresponding to the cluster of cluster number 16000 is present in the server SV, and the cluster is EOC.

  As described above, since data is managed in cluster units, it is possible to cope with changes in some clusters in the file, and the change is made to the cache file system in the terminal electronic device EQ. It can be reflected.

  Next, as shown in FIG. 8, the case where the file and file configuration in the server SV are further changed and the file set revision number is updated from r2 to r3 will be described.

  In the file set of revision number r3, file b. There is a file configuration change that bin is deleted, and file a. bin has been changed to be extended by 2 clusters. These changes are listed in the update list.

  FIG. 8 shows directory entries and FAT entries created based on the file set of revision number r3 downloaded from the server SV via the network NW and the update list.

  As shown in FIG. 8, the directory entry contains files a. bin and file d. The cluster numbers 1000 and 16000 of the respective leading clusters of bin are written.

  Also, in the management area of data in the local storage of the FAT entry, files a. The cluster number of the necessary part of the cluster in the bin and the value of the cluster number of the subsequent cluster are written.

  In the example of FIG. Of the eleven clusters constituting the bin, five clusters are downloaded and exist in the local storage 10, and the remaining six clusters are illustrated in the server SV. File a. The tenth and eleventh clusters of bin exist in the server SV as data corresponding to cluster number 12500 and cluster number 12501, respectively.

  That is, data corresponding to cluster number 1000 and cluster number 1001 exist in the local storage 10, the value for cluster number 1001 is 14000, and a cluster with cluster number 14000 exists in the server SV.

  The cluster number of the cluster following the cluster of cluster number 14000 is 11003, the data corresponding to cluster number 11003 exists in server SV, and the data corresponding to cluster number 11003 to cluster number 11005 exist in server SV There is. The value for the cluster number 11005 is 1500, and the cluster number of the cluster following the cluster with the cluster number 11005 is 1500.

  Also, data corresponding to cluster number 1500 exists in the local storage 10, and a cluster with a cluster number 1500 to a cluster number 1502 exists in the local storage 10, and the value for the cluster number 1502 is 12500, and the cluster number 12500 The data corresponding to exist in the server SV.

  The cluster number of the cluster following the cluster of cluster number 12500 is 12501, the data corresponding to cluster number 12501 exists in the server SV, and the cluster of cluster number 12501 is EOC.

  File d. The bin has a one-cluster configuration, and the one cluster exists in the server SV, and is written in the management area of the data in the server of the FAT entry.

  That is, data corresponding to the cluster number 16000 is present in the server SV, and the cluster is EOC.

  In the above description, an example was described in which the FAT entry is changed in the order of update in the case where the revision number of the file set is updated from r1 to r2 and further changed to r3, but the processing load on the terminal electronic device EQ It is good also as composition of updating to the latest revision at a stretch in order to reduce.

  That is, in order to synchronize with the file of the revision number r3 in the server SV, the terminal electronic device EQ having the information of the revision number r1 acquires the contents of change from the revision list r1 to the revision number r3 from the update list Need to be synchronized.

  On the other hand, if the update list from revision number r1 to revision number r3 is created in the server in advance, the terminal electronic equipment EQ having the information of revision number r1 is updated list from revision number r1 to revision number r3. This can be referred to, and the processing load can be reduced.

  FIG. 9 shows an example of downloading the update list from the revision number r1 to the revision number r3 from the server SV via the network NW to change the FAT entry.

  In the example of FIG. The third cluster of bin is changed to be expanded by two clusters as well as the file b. bin and file c. bin is deleted and file d. The file configuration change that bin is added is described in the update list. The directory entry and the FAT entry created based on such an update list are the same as in FIG.

  The method of confirming the change of the file and the file configuration in the server SV may be performed when the terminal electronic device EQ is activated or when the access from the terminal electronic device EQ in operation to the server SV occurs. For example, in the case of a file of a game program, the server SV is accessed when it is necessary to download data according to the progress of the game, so the change may be confirmed and updated at that time.

<About deleting cache>
Since the storage capacity of the local storage 10 is limited, it is necessary to delete the cache as appropriate. In the case of a normal file system, deletion of the cache is deletion of the file, but in the cache file system of the present invention, the corresponding file is operated by operating the FAT entry and deleting the line for managing the corresponding file from the FAT entry. You just need to indicate that all of the data is in the server.

  Also, as to which cache to delete, for example, there is a method of deleting a cache that has been used for the longest time. This is a simple method because it is easy to determine which cache is the oldest by referring to the time stamp information.

  Also, there is a method of saving the number of times of use of each file and deleting a cache whose number of times of use is lower than a specified value.

  Also, the cache to be deleted may be determined based on an instruction from the server. For example, in the case of a program for a game, there is unnecessary data due to the progress of the game, but such data is known in advance, and it is possible to respond based on instructions from the server according to the game progress. The cache may be deleted, or the correspondence list of the game progress status and the necessary / unnecessary files may be prepared in the server, and the terminal electronic device EQ may delete the cache as needed by referring to it.

  Moreover, although deletion object can not be decided, when the storage capacity of the local storage 10 is likely to run short, it may be deleted at random. The erase unit may be a file unit or a cluster unit.

  The determination of deletion of the cache of the local storage 10 may be made when the free capacity of the local storage 10 becomes smaller than the specified value or when accessing the server.

  In addition, when a certain unauthorized operation, for example, a modification of a program or the like is found for the cache file of the local storage 10, an instruction to delete the file may be given from the server SV. The detection of the unauthorized operation can be performed by CRC (Cyclic Redundancy Check) or the like of the cache file by the server SV.

<Modification of writing of FAT entry>
Hereinafter, a modified example of the writing of the FAT entry will be described with reference to FIGS.

  In the management area of the data in the server of the FAT entry, as for the data in the server, when the clusters are continuous, the value of the cluster number of the next following cluster is omitted, and the number of continuous clusters is recorded. Also good.

  For example, in the FAT entry shown in FIG. Of the nine clusters constituting the bin, three clusters are downloaded and exist in the local storage 10, and the remaining six clusters are illustrated as being present in the server.

  That is, data corresponding to cluster number 1000 to cluster number 1002 exist in the local storage 10, the value for cluster number 1002 is 11000, and the cluster number of the cluster following the cluster with cluster number 1002 is 11000. The data corresponding to the cluster number 11000 is present in the server SV.

  In the data corresponding to the cluster number 11000 of the management area of the in-server data, the number of consecutive points 6 is written and it is written that the next cluster is EOC. Thus, the file a. The fourth to ninth clusters of bin are in the server, and the ninth cluster is represented as EOC (end of file).

  Also, in the FAT entry shown in FIG. Of the nine clusters constituting the bin, six clusters are downloaded and exist in the local storage 10, and the remaining three clusters are illustrated as being present in the server.

  That is, data corresponding to cluster number 1000 to cluster number 1002 exist in the local storage 10, the value for cluster number 1002 is 11000, and the cluster number of the cluster following the cluster with cluster number 1002 is 11000. The data corresponding to the cluster number 11000 is present in the server SV.

  In the data corresponding to the cluster number 11000 in the management area of the in-server data, the number of consecutive 3s is written and that the next cluster is 3000 is written. Thus, the file a. It is shown that the fourth to sixth clusters of bin are in the server, and the seventh cluster is present in the cluster number 3000 of the local storage 10.

  By adopting the writing as described above, the display of the FAT entry can be simplified, and the storage capacity of the local storage 10 can be effectively used.

<Other application example>
In the embodiment described above, although the cache file system according to the present invention is applied to the FAT file system as an example, the application of the present invention is not limited to the FAT file system.

  For example, the present invention is also applicable to inodes used in Linux (registered trademark) file systems ext2 (second extended file system), ext3 (third extended file system), and ext4 (fourth extended file system).

  In the inode, a cluster is referred to as a block, and for example, "an array of a plurality of disk block addresses" in the inode represents a block number in which actual data is stored.

  It is the same as the FAT file system in that it creates a map indicating where in the file the data is located in the storage, and the cache file system according to the present invention can be applied.

  For example, if 11000 blocks exist in the local storage, if the block number in the inode has a value of 11000 or more (for example, the 11001st block), the data of that block is stored in the local storage Rather, it will only exist in the server.

  Thus, the application of the present invention is possible as long as it is a cache file system that creates a map indicating where in the local storage the data of the file is located.

  In the present invention, within the scope of the invention, the embodiment can be appropriately modified or omitted.

10 Local Storage 20 Cache File System EQ Terminal Electronics SV Server NW Network

Claims (12)

A terminal electronic device comprising a cache file system for downloading data of a file in a host device via a network and managing data cached in an internal storage device,
The cache file system is
A management table which is provided in the storage device and manages chain information indicating a connection between minimum management units constituting the file;
The management table is
By having the number of rows capable of managing the storage capacity exceeding the storage capacity of the storage device, and allocating the lines for the amount exceeding the storage capacity of the storage device to the management of the data of the file in the host device; Terminal electronic equipment that manages the data of the file in the host device as well as the data cached in the storage device. The cache file system is
Download the data of the file for each minimum management unit;
The management table is
The terminal electronic device according to claim 1, wherein the data of the file in the host device and the data cached in the storage device are managed for each of the minimum management units. The cache file system is
The terminal electronic device according to claim 1, wherein the data of the file in the host device is downloaded sequentially. The management table is
Divided into a management area of data in storage and a management area of data in host,
The data cached in the storage device is managed in a management area of the data in the storage device,
The terminal electronic device according to claim 3, wherein the data of the file in the host device is managed in a management area of the data in the host device. The cache file system is
The data cached in the storage device is deleted by deleting a line for managing the data cached in the storage device in the management area of the storage device data in the management table. Terminal electronics . The cache file system is
The terminal electronic device according to claim 5, wherein among the data cached in the storage device, data which has been used for a longest time since use is deleted. The cache file system is
The terminal electronic device according to claim 5, wherein among the data cached in the storage device, data whose usage count is lower than a specified value is deleted. The management table is
In the management area of data in the storage device,
The number assigned to each minimum management unit and the number of the next minimum management unit are recorded in one row.
In the management area of data in the host device,
When the minimum management unit is continuous,
5. The terminal electronic device according to claim 4, wherein the number of consecutive minimum management units is described in the first row of consecutive minimum management units. When there is a change in the file, the host device creates an update list indicating the contents of the change, adds a revision number, and manages it.
The cache file system is
When accessing the host device, the revision number managed by the host device is confirmed, and when the revision number is changed, the management table is changed with reference to the update list. The terminal electronic device according to Item 4 . The cache file system is
10. The terminal electronic device according to claim 9, wherein, when the file is updated, the management table is changed such that all data of the corresponding file or data of an updated part is in a management area of the in-host device data. The cache file system is
10. The terminal electronic device according to claim 9, wherein, when the file is added, the management table is changed such that all data of the corresponding file is in a management area of the data in the host device. The cache file system is
10. The terminal electronic device according to claim 9, wherein when the file is deleted, the management table is changed to delete all data of the corresponding file.

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