JP2001325140A - File transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a conventional file transfer device can transmit only a difference file of one generation and can not carry out efficient transmission based on the transfer of a difference file when changes of two generations or more are generated. SOLUTION: A server device 1 is provided with a difference storage part 12 for storing difference files in each version and a file synthesis/transmission part 14 for synthesizing and transmitting a difference file when the transmission of a difference file of two generation or more is necessary and constituted so as to synthesize the difference files stored in the difference storage part 12 on the basis of the version information of files stored in a client device 2 which is transmitted when the client device 2 is requested as necessity and transmit the synthesized file to the client device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a file transfer apparatus for efficiently transferring files that frequently change between computer systems connected by a network.

[0002]

2. Description of the Related Art As a means for efficiently transferring files that frequently change between computer systems connected by a network, there is a file transfer apparatus that improves the file transfer efficiency by utilizing the difference between changed files. . FIG. 11 is a functional block diagram showing a conventional file transfer apparatus using a difference between files disclosed in Japanese Patent Application Laid-Open No. 11-242588. In FIG. 11, reference numeral 101 denotes a central station that is a file transfer source, 102 is a base station that is a file transfer destination, and 103 is a central station 101.
And a communication line connecting the base station 102 with the base station 102. Central Office 10
Reference numeral 1 denotes a version storage unit 111 that stores the version of the program of the base station 102, a version monitoring unit 112 that monitors the version of the latest program, and a difference program that stores a difference program between the latest program and the program one generation before. The storage unit 113 and the base station 10
2 includes a transmission / reception control unit 114 for transmitting / receiving data to / from the PC 2 and a program storage unit 115 for storing the latest program. The base station 102 has a memory 12 for storing programs.
1 and a transmission / reception control unit 12 for transmitting / receiving to / from the central office 101
2, a download control processing unit 123, a version analysis unit 124, and a version storage unit 125.

Next, the operation will be described. Central Office 10
The first program storage unit 115 stores the latest program, the difference program storage unit 113 stores the difference program between the latest program and the previous generation program, and the version storage unit 111 stores the program stored in the memory 121 of the base station 102. Remember each version. The version monitoring unit 112 monitors the program stored in the program storage unit 115 and, when detecting that the program has been updated to a new program, when the version stored in the version storage unit 111 differs from the latest version by one generation. Transmits the difference program stored in the difference program storage unit 113 to the base station 102 via the transmission / reception control unit 114. The transmission / reception control unit 122 of the base station 102 receives the difference program, supplies the difference program to the download control processing unit 123, and reflects the difference program on the program stored in the memory 121.

[0004]

In a conventional file transfer apparatus for improving file transfer efficiency using a difference, a difference 1
Efficient transmission can be realized only in the case of the generation, but if the transmitting device has changed by two or more generations before the receiving device receives the data, the efficiency is improved by transferring the difference. Can not do. Small changes in the file occur frequently, and the file difference is stored in the difference program storage unit 1.
13, when the data receiving apparatus is not ready for immediate reception, or when the data receiving apparatus issues a file acquisition request due to the necessity of the data receiving apparatus, two or more generations of change are likely to occur. Thus, the situation where the file transfer can be efficiently performed by the differential transfer is limited. Further, in a file transfer device that can handle only one-generation differences, when the file is changed, the entire file is not registered in the transmission-side device, and the transfer method in which only the difference or the changed part is the target of the file transfer is more than two generations. Not available because changes may have occurred. Areas where it is effective to use transfer of only file differences or changed portions include a database change history, an edit history, an operation history, and the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. Even when file differences are accumulated over a plurality of generations, the differences are transmitted without sending the entire data. Accordingly, a first object is to obtain a file transfer device that realizes efficient data transmission.

It is a second object of the present invention to provide a file transfer apparatus that transfers only a changed portion in response to a change of a plurality of generations.

[0007]

In a file transfer apparatus according to the present invention, a server device having a difference storage unit for storing a difference file for each version of a file;
The server device is provided with a client device that notifies the server device of version information of the file stored therein and requests file transfer, and the server device responds to a difference between the version of the file stored by the client device and the version of the file to be transmitted. A transmission difference file is created using the difference file stored in the difference storage unit, and the created transmission difference file is transmitted to the client device. Further, when the difference between the version of the file stored by the client device and the version of the file to be transmitted is two or more generations, the server device combines and transmits the difference files stored in the difference storage unit. .

The server device has a client version information storage unit for storing version information of the file transmitted to the client device, and stores the version information in the difference storage unit using the version information stored in the client version information storage unit. This is to delete the specified difference file. The server device further includes a server device having a change information storage unit for storing change information for each version of the file, and a client device for notifying the server device of the version information of the file stored therein and requesting a file transfer. Creates transmission change information using the change information stored in the change information storage unit in accordance with the difference between the version of the file stored in the client device and the version of the file to be transmitted, and generates the generated transmission change information. Is transmitted to the client device.

[0009] When the difference between the version of the file stored in the client device and the version of the file to be transmitted is two or more generations, the server device combines and transmits the change information stored in the change information storage unit. Is what you do. In addition, the file that the server device transmits to the client device is the latest version of the file. In addition, the client device has a version selection unit that obtains version information of a file held by the server device from the server device and selects a version of a file requested to be transferred from the obtained version information. Requesting the server device to transfer the file of the specified version.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described. FIG. 1 is a diagram showing a configuration of a file transfer device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a server device that stores and transmits files, and 2 denotes a client device that receives and uses files from the server device 1. 3 is a server device 1,
This is a communication line for connecting the client device 2. Although a plurality of client devices 2 can be connected to the communication line 3, the first embodiment will be described with one client device 2 as one.

Next, the configuration of the server device 1 will be described. Reference numeral 11 denotes a file storage unit that stores a combination of a file and a file identifier, and the file identifier is configured by, for example, a file name or a numerical value that is distinguished from other files. Reference numeral 12 denotes a difference storage unit that stores a set of a file identifier, a version, and a difference between files, and the version is a numerical value or a character string that can indicate the order in which the file was updated, such as a number, a date, and the like. Description will be made using an integer value starting from 1. Reference numeral 13 compares the file identifier and the file input to the server device 1 with a file having the same file identifier in the file storage unit 11, updates the version and creates a difference file, and stores the file identifier and the version in the difference storage unit 12. And a file comparison and registration unit that stores the input file identifier, file, and version in the file storage unit 11 while storing the file identifier and the difference file. Reference numeral 14 denotes a file synthesizing transmission unit that creates a specified file or a difference file or a synthesis result of a difference file in response to a file acquisition request that specifies a file identifier and a version of the client device 2, and transmits the created file to the client device 2.

Next, the configuration of the client device 2 will be described. Reference numeral 21 denotes a received file / version storage unit that stores a file, a file identifier, and a version received by the client device 2. 22 retrieves a file identifier and a version from the received file / version storage unit 21 in response to a file acquisition request by inputting a file identifier, and
, A file acquisition request is made by designating a file identifier and a version, a file is acquired from the file synthesizing transmission unit 14, and the acquired file and the file in the reception file / version storage unit 21 are used to output a file. (Transmission difference file).

FIG. 2 is a flowchart showing the operation of the file comparison and registration unit of the file transfer device according to the first embodiment of the present invention. FIGS. 3 and 4 are flowcharts showing a file acquisition request of the file transfer device according to the first embodiment of the present invention.

First, the server 1 according to the first embodiment
Will be described with reference to FIG. The file and the file identifier are input to the file comparison and registration unit 13 (step S101), and the file and version corresponding to the input file identifier are searched from the files stored in the file storage unit 11 (step S102). . If there is no search result in step S103, the input file identifier and version are set to 1 (step S104), and the input file, file identifier, and version are stored in the file storage unit 11.
(Step S109), and the process ends. If the corresponding file exists in step S103, a difference file between the input file and the searched file is created (step S105). If the difference file is empty in step S106, the input file and the searched file are the same, and the process ends. When the difference file is extracted in step S106, the version is incremented by one (step S107), and the file identifier, the difference file extracted in step S105, and the updated version are stored in the difference storage unit 12 (step S107).
108), the input file, the file identifier, and the updated version are stored in the file storage unit 11 (step S109), and the process ends.

Next, an operation of requesting a file from the client device 2 to the server device 1 will be described with reference to FIGS.
This will be described with reference to FIG. FIGS. 3 and 4 are flowcharts illustrating the transmission and reception of files between the file reception / synthesis unit 22 of the client device 2 and the file synthesis / transmission unit 14 of the server device 1. First, when a file identifier of a requested file is input to the file receiving / synthesizing unit 22 of the client device 2 (step S201), a version corresponding to the input file identifier is searched from the received file / version storage unit 21 (step S201). S20
2). If there is no search result in step S203, the reference version is set to 0 (step S204), and step S204 is performed.
In 203, if there is a search result, the version of the search result is set as a reference version (step S205), and the reference version and the file identifier are transmitted to the file synthesizing transmission unit 14 of the server device 1 (step S206). Upon receiving the reference version and the file identifier from the client device 2 (step S207), the file synthesizing and transmitting unit 14 of the server device 1 searches for a file and a version corresponding to the file identifier received by the file storage unit 11, and (Step S208).

If the reference version is 0 at the time of comparison in step S209, the result data is regarded as the whole, and a file having the same identifier is designated as a result file in the file storage unit 11 (step S210). If the comparison in step S209 is not satisfied and the versions are equal at the time of comparison in step S211, the result data is updated and the result file is empty (step S212). If the comparison in step S211 is not established and the reference version is smaller by one in the comparison in step S213, the result data is regarded as a difference,
Among the difference files stored in the difference storage unit 12, a difference file having the same file identifier and matching the reference version is set as a result file (step S214).

When the comparison in step S213 is not satisfied,
The result data is set as a difference, and the difference storage unit 12 combines the difference files from the version retrieved in step S208 to the reference version + 1 to obtain a result file (step S215). The result file and the file storage unit The sizes of the files having the same identifier 11 are compared with each other (step S216).
When the size of the result file is large, the result data is regarded as the whole, and the file having the same file identifier in the file storage unit 11 is regarded as the result file (step S218).
Step S210, step S212, step S21
4. After each processing of step S218 or step S218
When the comparison at 217 is not established, the result data, the result file, and the searched version are set as the result version.
The file is transmitted to the file receiving / combining unit 22 of the client device 2 (step S219).

The file receiving / synthesizing unit 22 of the client device 2 waits until receiving the result from the file synthesizing and transmitting unit 14 of the server device 1 (step S220).
After the reception, the received result data is determined (step S2).
21). If the result data is the latest in step S222, a file corresponding to the input identifier is extracted from the received file / version storage unit 21 and is set as an output file (step S223). In step S224, when the result data is the whole, the received result file and the result version are stored in the received file / version storage unit 21 together with the file identifier, and the received file is set as the output file (step S225). Step S224
When the result data is not the latest data or the entire data, the received result file and the received file / version storage unit 21
The output file, the identifier, and the result version are stored in the received file / version storage unit 21 (step S226). Step S223, Step S22
5. After each processing in step S226, the file reception / combination unit 22 outputs an output file (step S22).
7).

According to the first embodiment, when the versions are equal at the time of requesting a file, the client apparatus 2 uses the file held in the client apparatus 2 as the requested file, so that the transmission amount is minimized. When one version is different, only the difference file is transmitted, so that the transmission amount is reduced. When two or more versions are different and the synthesis result of the difference file is smaller than the latest file, the synthesized difference is transmitted. In addition, the transmission amount is reduced, and in many cases, the transmission amount can be reduced, and as a result, high speed can be realized.

Embodiment 2 FIG. 5 is a diagram showing a configuration of the file transfer device according to the second embodiment of the present invention.
5, 1-3, 11-14, 21, and 22 correspond to FIG.
Are the same as those in. Reference numeral 15 denotes a client version information storage unit that stores the file acquisition status of the client device 2.

In the first embodiment, each time a file is registered in the server device 1, a difference file is accumulated in the difference storage unit 12. In the second embodiment, as shown in FIG. The client version information storage unit 15 for storing the file acquisition status of the client device 2 is added, and the client device 2 is provided with a function of automatically deleting the acquired difference file. Is prevented from accumulating. The client version information storage unit 15 according to the second embodiment stores a file identifier of a file transmitted to the client device 2, a version transmitted last, and a client device identifier for identifying the client device 2.

Next, the operation of the file transfer device according to the second embodiment will be described. The file registration operation is the same as that shown in FIG. 2 of the first embodiment. After transmitting the result data, the result file, and the result version to the client device 2 in step S219 of FIG. 4 showing the file transmission / reception operation of the first embodiment, the client device information storage unit 15 transmits the transmitted client device 2
, A file identifier corresponding to the transmitted file, and a result version set are updated. Next, all versions corresponding to the changed file identifier are searched from the client version information storage unit 15, and the oldest version is extracted. The difference storage unit 12 determines whether the file identifier is equal and the version is equal to or greater than the version of the search result. If there is an old file identifier / version / difference file pair,
delete.

According to the second embodiment, the differential file that has been transmitted to all the client devices 2 is not left, and no unnecessary files are left in the server device 1. Storage efficiency is improved. In addition, since the version of the file acquired by each client device 2 remains in the server device 1, the administrator of the server device 1 refers to the acquisition status of the latest file of each client device 2 on the server device 1 side. However, if there is a problem, extension such as prompting the client device 2 to acquire a file can be performed.

Embodiment 3 FIG. FIG. 6 is a diagram showing a configuration of a file transfer device according to Embodiment 3 of the present invention.
6, 1-3, 11-14, 21, and 22 correspond to FIG.
Are the same as those in. Reference numeral 23 denotes a version selection unit that acquires a list of versions held by the server device 1 corresponding to the input file identifier, and selects an arbitrary version from the list. FIGS. 7 and 8 are flowcharts showing a file acquisition request of the file transfer device according to the third embodiment of the present invention. Embodiments 1 and 2
In the third embodiment, the latest file is transmitted to the client device 2. In the third embodiment, as shown in FIG. 6, the client device 2 is provided with a version selection unit 23, and the server device 1 corresponding to the specified file identifier is provided. , An arbitrary version is selected from a list of each version existing in, and a file of the selected version can be obtained.

Next, the operation of the file transfer device according to the second embodiment will be described with reference to FIGS. The operation of the file comparison and registration unit 13 of the server device 1 is the same as that of the first embodiment. FIGS. 7 and 8 are flowcharts illustrating file transmission / reception performed between the file reception / synthesis unit 22 and the version selection unit 23 of the client device 2 and the file synthesis / transmission unit 14 of the server device 1.
First, in the client device 2, a file identifier to be acquired is input to the version selecting unit 23 (step S301), and the file receiving / synthesizing unit 22 specifies the file identifier and sends a version list request to the file of the server device 1. (S30)
2). Upon receiving the file identifier and the version list request (step S303), the file synthesizing transmission unit 14 of the server device 1 searches for all the versions corresponding to the file identifier requested from the file storage unit 11 (step S304), and The search result is transmitted to the data reception / synthesis unit 22 of the client device 2 (Step S)
305).

Data receiving / synthesizing unit 2 of client device 2
2 waits for the reception of the result from the server device 1 (step S
306), upon reception, the received result is passed to the version selection unit 23 (step S307), and the version selection unit 23 displays a version list (step S30).
8) Then, a necessary version is selected (step S).
309), the data receiving / synthesizing unit 22 searches the received file / version storage unit 21 for a version corresponding to the file identifier (Step S310). Step S3
In step 11, if there is no search result, the reference version is set to 0 (step S312). If there is a search result, the reference version is set to the version of the search result (step S31).
3) The file identifier, the reference version, and the selected version are transmitted to the file synthesizing transmission unit 14 of the server device 1 (Step S314). The file synthesizing transmission unit 14 of the server device 1 receives the file identifier, the selected version, and the reference version (Step S315), and compares the selected version with the reference version.

At step S316, it is checked whether the selected version and the reference version are equal. If they are equal, the result data and the result file are omitted (step S317).
If they are not equal, in step S318, it is compared whether the selected version is larger than the reference version. If the selected version is larger, the difference file from the reference version +1 to the selected version is taken out from the difference storage unit 12 and combined as a result file. The result data is upgraded (step S319). If the reference version is larger than the selected version in step S318, the difference file from the selected version to the reference version -1 is taken out from the difference storage unit 12, synthesized to be a result file, and the result data is downgraded (step S3).
20). After the processing of steps S317, S319, and S320, the result data and the result file are transmitted to the file reception / combination unit 22 of the client device 2 (step S321).

The file receiving / synthesizing unit 22 of the client device 2 receives the result data and the result file from the server device 1 (Step S322). In step S323,
It is checked whether there is no result data. If there is no result data, a file corresponding to the file identifier is extracted from the received file / version storage unit 21 and output as an output file (step S324). Check if it is up (Step S3
25) When the version is upgraded, the received file
The file corresponding to the file identifier is extracted from the version storage unit 21, combined with the result file, and a version-upgraded file is generated as an output file (step S326). The file corresponding to the file identifier is fetched from the storage unit 21 and combined with the result file in a reverse manner, and a version-downgraded file is generated as an output file (step S327).
After the processing in steps S326 and S327, the output file and the selected version are stored in the received file / version storage unit 21 (step S328). Step S
324 and step S328, the output file is output from the version selection unit 23 (step S32).
9).

According to the third embodiment, since the version can be selected, it can be used when the client device 2 wants to acquire a file older than the latest one, or wants to acquire a file reflecting one generation at a time. In addition, when a problem occurs after the acquisition of a file, a version down operation for reverting to a previous version can be similarly realized only by transmitting a difference between files.

Embodiment 4 In the first, second, and third embodiments, the file comparison / registration unit 13 handles a difference file obtained by comparing files.
As shown in (1), the server device 1 registers change information instead of the file difference, and
Also, change information is acquired and used. Here, the change information is represented by a set of information before and after the change, such as when data A is changed to data B.

FIG. 9 is a diagram showing a configuration of a file transfer device according to the fourth embodiment of the present invention. In FIG.
1 to 3 are the same as those in FIG. Reference numeral 31 denotes a change information storage unit that stores a set of a file identifier, a version, and change information. The version in the fourth embodiment is also a numerical value or a character string that can indicate the same order as in the first embodiment. In the following description, the version will be described as an integer value starting from 1. A change information registration unit 32 changes the version corresponding to the file identifier when the file identifier and the change information are input, and stores the file identifier, the updated version, and the change information in the change information storage unit 31. Reference numeral 33 denotes a change synthesizing transmission unit that synthesizes and transmits change data (transmission change information) in response to a request from the client device 2, and 31 to 33 configure the server device 1. Reference numeral 41 denotes a reflection version storage unit that stores the file identifier and the version received by the client device 2. 42, when the file identifier is input, the file identifier is transmitted to the change synthesizing transmission unit 33 of the server device 1.
And a change receiving / combining unit that receives the result and outputs the change information, and configures the client device 2 together with the reflected version storage unit 41.

Next, the operation of the file transfer device according to the fourth embodiment will be described. First, an operation when registering change information in the server device 1 according to the fourth embodiment will be described. When a set of a file identifier and change information is input to the change information registration unit 32 of the server device 1, the maximum version corresponding to the file identifier is searched from the change information storage unit 31, and 1 is added to the version. A set of the version, the file identifier, and the change information is registered in the change information storage unit 31.

Next, the operation of requesting and receiving a file from the client device 2 to the server device 1 will be described. When the file identifier is input, the change reception combining unit 42 of the client device 2
Read the version corresponding to the file identifier from
It requests the change combining transmission unit 33 of the server device 1 to transmit the change information by designating the file identifier and the version. The change synthesizing transmission unit 33 of the server device 1
, A file identifier and a version are received from the change information storage unit 31, a version corresponding to the file identifier is searched for a version and a file subsequent to the received version, change information is synthesized from the searched file, and the synthesized change The information and the maximum version are transmitted to the change reception synthesis unit 42 of the client device 2. Here, when synthesizing a plurality of pieces of change information, the change synthesizing transmission unit 33 combines, for example, change information for changing data A to data B and change information for changing data B to data C, and C is changed so that the size of the change information can be minimized during data synthesis. The change reception synthesis unit 42 of the client device 2 receives the change information and the maximum version from the server device 1, stores the file identifier and the version in the reflection version storage unit 41, and outputs the change information.

According to the fourth embodiment, the server 1
Since the change information is output instead of the latest file, it can be used when there is a mechanism for performing processing using the change information on the client device 2 side. For example, using the change information indicating that data A has been changed to data B, all data A used by
The change can be reflected by replacing with. Further, since the amount of change information is reduced by combining the change information a plurality of times at the time of combining, it is possible to reduce the amount of data transmission and the amount of change reflected in the client device.

Embodiment 5 FIG. FIG. 10 is a diagram showing a configuration of a file transfer device according to the fifth embodiment of the present invention. In FIG. 10, 1-3, 31-33, 41, 42
Are the same as those in FIG. Reference numeral 43 denotes a version selection unit for acquiring a list of versions held by the server device 1 corresponding to the input file identifier and selecting an arbitrary version therefrom. In the fourth embodiment,
Although the latest data change information is acquired, in the fifth embodiment, as shown in FIG. 10, a version selecting unit 43 is provided in the client device 2, and the server device 1 corresponding to the specified file identifier is provided. , An arbitrary version is selected from a list of each version existing in the list, and a file of the selected version can be obtained.

Next, the operation of the file transfer device according to the fifth embodiment will be described. Change information registration unit 3 of server device 1
The operation of registering the change information to the second is the same as the operation of the fourth embodiment. Next, from the client device 2 to the server device 1
Next, the operation of requesting and receiving a file will be described. The operation of the version selection unit 43 is similar to that of FIGS. 7 and 8 in the third embodiment, in which a version list request is made, a required version is selected from the obtained version list, and a file identifier and a version are specified. As in the third embodiment, change data is acquired from the server device 1.

According to the fifth embodiment, since the latest version can be selected instead of automatically acquiring the latest version, the client apparatus 2 may want to acquire information before the latest, or may reflect the information one generation at a time. This can be used when it is desired to acquire change information, and can be used in a wider range than in the fourth embodiment. Further, when there is a problem after the change information is reflected, it is possible to return to the past data.

[0038]

Since the present invention is configured as described above, it has the following effects. A server device having a difference storage unit for storing a difference file for each file version, and a client device for notifying the server device of version information of the file to be stored and requesting a file transfer; According to the difference between the version of the file stored in the device and the version of the file to be transmitted, a transmission difference file is created using the difference file stored in the difference storage unit, and the created transmission difference file is transmitted to the client device. Since the transmission is performed, the transmission amount of the file to be transmitted can be reduced.

When the difference between the version of the file stored in the client device and the version of the file to be transmitted is two or more generations, the server combines and transmits the difference files stored in the difference storage unit. So
The transmission amount of the file to be transmitted can be further reduced. Further, the server device has a client version information storage unit that stores version information of the file transmitted to the client device, and is stored in the difference storage unit using the version information stored in the client version information storage unit. Since the difference file is deleted, unnecessary difference files can be prevented from being stored.

Further, a server device having a change information storage unit for storing change information for each version of a file, and a client device for notifying the server device of the version information of the file to be stored and requesting file transfer are provided. The server device creates transmission change information by using the change information stored in the change information storage unit in accordance with the difference between the version of the file stored by the client device and the version of the file to be transmitted. Since the transmission change information is transmitted to the client device, the transmission amount of the file to be transmitted can be reduced.

If the difference between the version of the file stored in the client device and the version of the file to be transmitted is two or more generations, the server device combines and transmits the change information stored in the change information storage unit. So
The transmission amount of the file to be transmitted can be further reduced. In addition, since the file transmitted from the server device to the client device is the latest version file, the latest version file can be transferred. In addition, the client device has a version selection unit that obtains version information of a file held by the server device from the server device and selects a version of a file requested to be transferred from the obtained version information. Since the server is requested to transfer the file of the specified version, the file can be requested by designating the version.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a file transfer device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a file comparison and registration unit of the file transfer device according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating a file acquisition request of the file transfer device according to the first embodiment of the present invention.

FIG. 4 is a flowchart showing a file acquisition request of the file transfer device according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a file transfer device according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a file transfer device according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing a file acquisition request of a file transfer device according to a third embodiment of the present invention.

FIG. 8 is a flowchart showing a file acquisition request of a file transfer device according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a file transfer device according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a file transfer device according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a conventional file transfer device.

[Explanation of symbols]

1 server device, 2 client device, 3 communication line, 11 file storage unit, 12 difference storage unit, 13
File comparison registration unit, 14 File synthesis transmission unit, 15
Client version information storage unit, 21 received file / version storage unit, 22 file reception synthesis unit,
23 Version selection part, 31 Change information storage part, 32
A change information registration unit, 33 a change synthesis transmission unit, 41 a reflection version storage unit, 42 a change reception synthesis unit, 43 a version selection unit;

Claims (7)

[Claims] 1. A file transfer device for transferring a frequently updated file between two devices via a communication line, a server device having a difference storage unit for storing a difference file for each file version, and the server device A client device that requests file transfer by notifying the version information of the file stored by itself, and the server device, according to the difference between the version of the file stored by the client device and the version of the file to be transmitted,
A file transfer device, wherein a transmission difference file is created using a difference file stored in a difference storage unit, and the created transmission difference file is transmitted to the client device. 2. When the difference between the version of the file stored by the client device and the version of the file to be transmitted is two or more generations, the server device combines and transmits the difference file stored in the difference storage unit. The file transfer device according to claim 1, wherein: 3. The server device has a client version information storage unit for storing version information of a file transmitted to the client device, and stores the version information stored in the client version information storage unit in a difference storage unit. 3. The file transfer device according to claim 1, wherein the stored difference file is deleted. 4. A server device having a change information storage unit for storing change information for each version of a file in a file transfer device for transferring a frequently updated file between two devices via a communication line. A client device that requests the file transfer by notifying the device of the version information of the file stored therein, the server device according to a difference between the version of the file stored by the client device and the version of the file to be transmitted,
A file transfer device, wherein transmission change information is created using change information stored in a change information storage unit, and the created transmission change information is transmitted to the client device. 5. When the difference between the version of the file stored in the client device and the version of the file to be transmitted is two or more generations, the server device combines and transmits the change information stored in the change information storage unit. The file transfer device according to claim 4, wherein the file transfer is performed. 6. The file transfer device according to claim 1, wherein the file transmitted from the server device to the client device is a latest version of the file. 7. The client device has a version selection unit that obtains version information of a file held by the server device from the server device and selects a version of a file requested to be transferred from the obtained version information, The file transfer device according to any one of claims 1 to 5, wherein the file transfer device requests the server device to transfer a file of a version selected by the version selection unit.