JP2003288253A - Data communication method, data communication system, information processing device, and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a processing speed for sharing data between information processing devices. <P>SOLUTION: The information processing device A requires peer-to-peer communication from the information processing device B for establishing connection (S11, S21). In this process, the information processing device A compares levels showing computing processing in both devices for determining one having higher computing ability level in the information processing devices (S12). As the information processing device B has higher level, the information processing device B compares message file lists of the information processing devices A and B for forming a differential list between them (S24). The information processing device B extracts differential data on the basis of the differential list and transmits it to the information processing device A (S25). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peer-to-peer communication technique, and more particularly to a technique for high-speed peer-to-peer data sharing.

[0002]

BACKGROUND OF THE INVENTION As a form of an information processing system, a plurality of information processing devices respectively manage data, and each information processing device is managed by a client / server system in which all data is centrally managed by a server. Peer-to-Peer (hereinafter P) operating in cooperation
2P) method.

In the P2P system, when one information processing device shares data with another information processing device, the other device acquires data which the other device holds but does not hold, and the data is synchronized. Must be taken. At this time, both the own device and the partner device create lists of data held by the respective devices, compare these, and extract difference data.

Here, when the number of data held by each information processing device is small, it does not become a problem so much, but as the number of data increases, the load of the process of comparing the lists and extracting the difference data becomes heavy. It will take time.

Therefore, an object of the present invention is to speed up the processing for an information processing apparatus to share data with another information processing apparatus.

[0006]

A data communication system according to one embodiment of the present invention includes a first information processing device,
And a second information processing device. When the second information processing device has better processing performance than the first information processing device, the first information processing device displays the first list indicating the data stored in the first information processing device as the first list. Second information processing device, the second information processing device is configured to transmit to the first information processing device.
And a first difference data stored in the second information processing device and not stored in the first information processing device, based on the first data list. And means for transmitting the first difference data to the first information processing apparatus.

In a preferred embodiment, the first information processing device is a difference data list indicating second difference data stored in the first information processing device and not stored in the second information processing device. And means for receiving the second difference data based on the difference data list, and means for transmitting the second difference data to the second information processing apparatus. The second information processing apparatus further includes means for generating the difference data list based on the first data list, and means for transmitting the difference data list to the first information processing apparatus.

An information processing apparatus according to another embodiment of the present invention includes a storage section for storing information indicating the processing performance of its own apparatus,
Comparing means for acquiring information indicating the processing performance of the communication partner device from the communication partner device and comparing the processing performance of the own device with the processing performance of the communication partner device; and the result of the comparison, the own device. Is superior in processing performance, a list of data stored in the device of the communication partner is acquired, and a difference list indicating difference data between data stored in the device of the communication partner and data stored in the own device is created. Means, and means for acquiring the difference data from the communication partner device based on the difference list.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A network communication system for data sharing according to an embodiment to which the present invention is applied will be described below with reference to the drawings. The present system is a system for performing distributed processing by a so-called peer-to-peer method in which information processing apparatuses connected via a network directly communicate with each other without using an intermediary server. In the first embodiment shown in FIG. 1, the information processing devices 1, 1, ... Are connected to the network 9. In the following description, the information processing apparatus A and the information processing apparatus B communicate with each other by P2P, and data (message described later in this embodiment)
To share.

The information processing devices 1, 1, ...
It is configured by a general-purpose computer system having a U, a memory, an external storage device, and the like, and the constituent elements or functions described below are realized by executing a computer program, for example.

The functional configuration of the information processing device 1 is shown in FIG.
The information processing device 1 is connected to an input device 2 such as a keyboard or a pointing device, and an output device 3 such as a CRT or a liquid crystal display device. The information processing device 1 includes a network interface unit 11,
A message storage unit 12, a personal information storage unit 13 that stores individual information of the information processing device, and an input / output device control unit 14
And the arithmetic processing unit 15 as its internal functions.

The network interface section 11 controls communication with another information processing apparatus connected to the network 9. For example, the network interface unit 11 performs control for establishing a connection for communicating with another information processing device, and control for disconnecting the connection when terminating communication. Further, the network interface unit 11 sends and receives data such as message files.

The message storage unit 12 stores posted message files. In the present embodiment, two information processing apparatuses exchange files by P2P to share the message file stored in the message storage unit 12. An example of the data structure of the message file 20 stored in the message storage unit 12 is shown in FIG.
The message file 20 has a header 21 and a body 25 as data items. The header 21 further includes
Contributor's email address (From) 211, newsgroup name (Newsgroup) 212, and subject (Subject) 21 indicating the subject of the message
3, the posting date / time (Date) 214 of the message, and the message ID (Me) for uniquely identifying the message.
message-ID) 215 and a reference message ID (Reference) when another message is referenced
216 and. Body 25 is message body 251
It is composed of

Returning to FIG. 2, the storage unit 13 stores individual information of the information processing apparatus itself. For example, a device ID 131 for uniquely identifying the device itself on the network
And processing level 1 indicating the performance of the processing of its own device
32 is stored. As the device ID 131, for example, an IP address or a MAC address can be used. The calculation processing level 132 is determined based on the calculation capability of the MIPS value of the own device, for example. In this embodiment, the arithmetic processing level 132 is set to five levels from level 1 to level 5, and the processing performance increases as the number increases.

The input / output device controller 14 controls the input device 2 and the output device 3.

The arithmetic processing unit 15 performs various arithmetic operations. For example, the arithmetic processing unit 15 creates a list of message files stored in the message storage unit 12. In the present embodiment, the message file list includes at least the message ID 215.

Further, the arithmetic processing unit 15 determines the superiority or inferiority of the arithmetic processing performance of its own apparatus and the arithmetic processing performance of another information processing apparatus which is a communication partner. This determination of superiority or inferiority is performed, for example, with reference to the arithmetic processing level 132. As a result of this superiority or inferiority determination, the information processing device having excellent processing performance creates the next difference list.

The arithmetic processing unit 15 further compares the message file list of the other information processing apparatus as the communication partner with the message file list of its own apparatus to create a difference list. For example, the arithmetic processing unit 15 sorts the message IDs of both message file lists and compares them with each other to create a difference list. The difference list is, for example, a list of message files (type 1) that is stored in the information processing apparatus that has made the connection request but not stored in the information processing apparatus that has received the connection request. On the contrary, a list of message files (type 2) stored in the information processing apparatus that has received the connection request but not stored in the information processing apparatus that has made the connection request, or both of these ( It may be type 3). Which type of difference list the arithmetic processing unit 15 creates can be determined from time to time. Furthermore, the arithmetic processing unit 15
Extracts a message file (difference file) corresponding to the difference from the message storage unit 12 based on the difference list.

Next, a processing procedure when the information processing apparatus A and the information processing apparatus B exchange messages to synchronize data will be described with reference to FIGS. 4 and 5. Since both the information processing apparatus A and the information processing apparatus B have the same configuration (see FIG. 2), in the following description, A or B may be added after the reference numeral to distinguish them. .

First, the network interface section 11A of the information processing apparatus A sends a connection request to the information processing apparatus B (S101). In this connection request, the device ID 131B of the information processing device B is designated as the transmission destination, and the device ID 131A of the information processing device A is included as the transmission source.

The network interface unit 11B of the information processing apparatus B receives the connection request and performs a reception process for establishing the connection. At this time, the network interface unit 11B transmits the arithmetic processing level 132B of its own device to the information processing device A (S201).
Here, the arithmetic processing level 132B of the information processing apparatus B is set to "level 5".

The arithmetic processing unit 15A of the information processing apparatus A compares the arithmetic processing level 132B of the information processing apparatus B with the arithmetic processing level 132A of its own apparatus to determine superiority or inferiority (S).
102). Here, the arithmetic processing level 132A of the information processing apparatus A is set to "level 3". As a result of this comparison, it can be seen that the information processing apparatus B has a higher arithmetic processing level than the information processing apparatus A. Therefore, the difference list is created by the information processing apparatus B, which is superior in arithmetic processing performance.

Therefore, first, the arithmetic processing unit 15A of the information processing apparatus A creates a list of message files stored in the message storage unit 12A (S10).
3). Then, the list is transmitted to the information processing apparatus B, and the creation of the difference list is requested (S104).

In the information processing apparatus B, the arithmetic processing unit 15B
A list of message files stored in the message storage unit 12B is created (S202). Then, the arithmetic processing unit 15B compares the list of the information processing device B created here with the list of the information processing device A to create a difference list (S203). The type of the difference list created here is type 1 or type 2. Here, type 2 is a difference between files stored in the information processing apparatus (information processing apparatus B) that has received the connection request but not stored in the information processing apparatus (information processing apparatus A) that has made the connection request. A list (insufficient list of information processing apparatus A) is created.

The arithmetic processing unit 15B extracts a difference file from the message file storage unit 12B based on this difference list and transmits it to the information processing apparatus A (S20).
4).

When the information processing apparatus A completes the reception of the difference message file (S105), it disconnects the connection with the information processing apparatus B and the communication is completed (S1).
06, S205).

In the example shown in FIG. 4, the information processing apparatus A only acquires the message file held by the information processing apparatus B, and the information processing apparatus B does not acquire the message file held by the information processing apparatus A. Therefore, in the example shown in FIG. 5, both the information processing apparatuses A and B acquire the message file held by the partner apparatus.

Steps S101 to S1 of the information processing apparatus A
04 and steps S201 to S20 of the information processing apparatus B
Up to 2 is the same as in the case of FIG.

The arithmetic processing unit 15B of the information processing apparatus B compares the list of the information processing apparatus B created in step 202 with the list of the information processing apparatus A to create a type 3 difference list (S211). . That is, the difference list of files stored in the information processing apparatus A and not stored in the information processing apparatus B (insufficient list of the information processing apparatus B) and the information processing apparatus B stored in the information processing apparatus B A difference list of files not stored in A (a lack list of information processing apparatus A) is created. Arithmetic processing unit 1
5B extracts the difference file stored in its own device and not stored in the information processing device A from the message file storage unit 12B (S212). Then, the difference file and the difference list are transmitted to the information processing apparatus A (S2).
13). The difference list transmitted at this time may be only the list of message files that the information processing apparatus B lacks.

The information processing apparatus A receives this difference file and the difference message (S111). Then, the arithmetic processing unit 15A extracts the difference file stored in the information processing apparatus A and not stored in the information processing apparatus B from the message file storage unit 12A, and the information processing apparatus B
(S112).

When the information processing device B completes the reception of the difference file (S214), the information processing device A and the information processing device B disconnect the connection and terminate the communication (S).
113, S215).

In the example of FIGS. 4 and 5, the information processing apparatus B is used.
When the processing performance of the information processing apparatus A is superior, the information processing apparatus A
Acquires the message file list from the information processing apparatus B, and the information processing apparatus A performs the processing corresponding to the creation of the difference list in steps S203 and S211.

As a result, the information processing apparatus having a high processing capability performs the heavy file comparison, so that the processing for file sharing in P2P can be speeded up.

Next, a second embodiment will be described.
In the description of the present embodiment, parts different from the first embodiment will be mainly described, and description of common parts may be omitted.

In the communication system according to this embodiment, as shown in FIG. 6, information processing devices 1, 1 ... And a support server 5 are connected to a network 9, respectively.

The support server 5 is composed of, for example, a general-purpose computer system having a CPU, a memory, an external storage device, etc., and the components or functions described below are realized by executing a computer program, for example. To be done.

The support server 5 includes the information processing devices 1, 1
When they communicate with each other in P2P, they provide a service for supporting communication. For example, in the first embodiment,
When the information processing apparatuses share the file in P2P communication, one of the information processing apparatuses compares the message file lists and creates the difference list. In the present embodiment, the support server 5 does this. . Therefore, the support server 5 can perform file sharing in P2P at high speed by providing a configuration capable of performing the process of comparing the lists at high speed.

Further, the support server 5 provides various additional services other than the above. The support server 5 will be described below.

The support server 5, as shown in FIG.
As its internal function, the network interface unit 5
1, a calculation processing unit 52, a billing processing unit 53, a user information storage unit 54, an additional service information storage unit 55, and a history storage unit 56.

The network interface section 51 controls communication with other devices connected to the network 9. For example, the information processing apparatus 1 connected to the network 9 receives the ID of the information processing apparatus that is the transmission source and the list of message files, and returns the difference list created in the process described below. Alternatively, the network interface unit 51 receives a request for an additional service, which will be described later, and returns predetermined information corresponding to the request.

Here, the message file list 6 received by the network interface unit 51 in the present embodiment.
An example of 0 is shown in FIG. Message file list 60
Includes, for example, a message ID 61, a contributor's mail address 62, and a subject 63.

The arithmetic processing section 52 is a difference list creation process,
And processing for providing an additional service described later is performed. In the difference list creating process, for example, when the information processing apparatuses A and B exchange files by P2P, the support server 5 acquires the message file list from each of the information processing apparatuses A and B, and compares the lists. To create a difference list. Further, the arithmetic processing unit 52 executes processing for various additional services, and a specific example of the additional services will be described later together with the storage content of the additional service information storage unit 55.

In the user information storage section 54, personal information of each user is registered in advance. For example, as shown in FIG. 9, the user information storage unit 54 has a user's mail address 541, a keyword 542, and billing information 543 as data items.

The user's mail address 541 is identification information for uniquely identifying the user in this system.

The keyword 542 is a keyword representing the characteristics of each user, and is, for example, a keyword associated with a field in which the user is interested or a matter for which information is desired to be collected. The keyword is created by each user by himself / herself and is registered in advance, or is learned by the support server 5 by a learning processing unit (not shown) as the user repeatedly uses the keyword.

The billing information 543 is information required for billing each user, and is, for example, a credit card number, a bank account number, a member ID, or any other unique information for identifying an individual. Information.

When the above service is provided for a fee, the charge processing unit 53 charges the user of the service. For example, the charging processing unit 53 determines the amount of money according to the type of service provided or the time required for processing to provide the service, and charges each user based on the charging information 543.

The additional service information storage section 55 stores information for use in additional services. Specific examples of data stored in the additional service information storage unit 55 will be described together with specific examples of the additional services A to D described below.

The additional service A is a service for weighting the difference list in accordance with the user's preference when the arithmetic processing unit 52 compares the message file lists and creates the difference list. The weighting is performed, for example, by sorting the records in the difference list based on the user information storage, as described below.

The difference list has the same data items as the message file list 60 (see FIG. 8). The destination email address of the difference list is defined. Here, the arithmetic processing unit 52 uses the mail address 541 as a key to determine the subject 6 of the records included in the difference list.
3 is compared with the keyword 542 of the user information storage unit 54. When the subject 63 and the keyword 542 match, a score is given to each record according to the number of matching keywords. Then, the records in the difference list are sorted in the descending order of scores, that is, in the order of matching the characteristics of the user.

Here, the case where the subject and the keyword match includes not only the case where the subject and the keyword completely match, but also the case where the subject and the keyword match with each other using morphological analysis or thesaurus. May be.

The additional service B is a service in which the arithmetic processing unit 52 translates the subjects included in the difference list using a translation dictionary (not shown). The type or number of languages that can be translated is determined according to the type and number of translation dictionaries included in the support server 5.

The additional service C is a service for filtering a difference list to remove a predetermined record. The record to be removed is, for example, the ID of a message that may contain a virus or the like.

The additional service information storage unit 55 stores information to be deleted, which is a list of message IDs of messages that may include information such as viruses and antisocial messages. The arithmetic processing unit 52 checks whether the message ID registered in the deletion target information is included in the difference list. Then, when the message list registered in the deletion target information is included in the difference list, the arithmetic processing unit 52 deletes the message ID from the difference list.

The additional service D is a service for each information processing apparatus 1 to delete the message stored in the message storage unit 12. This function can be used, for example, when the contributor himself / herself wants to delete a message posted for some reason, or when a person who has the authority deletes a message even if the message is posted by another person.

The additional service information storage unit 55 stores a deletion list which is a list of message IDs of messages to be deleted. The user can register the message ID to be deleted in the deletion list at any time, but the contents to be registered are different between a privileged user having a predetermined authority and a normal user having no authority.

First, when a normal user registers in the deletion list, the message ID to be deleted and the mail address of the registrant are registered.

The arithmetic processing unit 52 compares the message file list sent from each information processing device 1 with the deletion list before performing the list comparison for creating the difference list. Then, when both the message ID 61 of the message file list and the mail address 62 of the contributor match those registered in the deletion list, the arithmetic processing unit 52 retrieves the record of the message ID from the message file list. delete. When only one of the message ID 61 and the mail address 62 of the poster matches, the arithmetic processing unit 52 does not delete the record of the message ID from the message file list. By doing so, the normal user can delete only the message posted by himself, and cannot delete the other messages.

Next, when a privileged user registers in the deletion list, a predetermined simple password or a systematic encryption key is input to confirm whether the registrant is a privileged privileged user. . When it is confirmed that the user is a privileged user, only the message ID is registered in the deletion list.

At this time, as in the case described above, the arithmetic processing unit 52, before performing the list comparison for creating the difference list, sends the message file list sent from each information processing device 1 and the deletion list. Compare with. If the message ID 61 of the message file list matches that registered in the deletion list, the arithmetic processing unit 52
Deletes the record with that message ID from the message file list. That is, in this case, no matter who posted the message, if the message IDs match, the arithmetic processing unit 52 deletes the record from the message file list. This allows privileged users to delete from the message file list, not just messages posted by themselves.

As a result, when the message to be deleted is registered in the deletion list, the message to be deleted will not be extracted as a difference file, so that it should be transferred to another information processing device at least after that point. Disappears.

Further, in the message file list sent from the information processing device 1, the message ID to be deleted is set.
When the message includes, the support server 5 may instruct the information processing device of the transmission source to delete this message. As a result, the deletion target message is deleted from the information processing device that has transferred the message file list to the support server 5.

In addition, P2P using the support server 5
If the information processing apparatus 1 that shared the file in step 1 holds the message to be deleted registered in the deletion list, the arithmetic processing unit 52 creates a deletion request and sends it to the information processing apparatus to delete it. You may do it. When performing this process, the history storage unit 56 is used.

The history storage unit 56 stores the history of services provided by the support server 5. The history storage unit 56 is
For example, as shown in FIG. 11, the mail addresses 561 of the two information processing apparatuses that have performed P2P communication and the difference list 562 that has been transmitted to each mail address are stored in association with each other.

The arithmetic processing unit 52 compares the deletion list with the transmitted difference list 562 stored in the history storage unit 56, and determines whether the deletion list includes a registered message ID. The sent difference list 56 including the message IDs registered in the deletion list
If there is 2, it is associated with the difference list 562,
The deletion request is transmitted to the destination mail address 561.

As a result, the message to be deleted can be deleted from the information processing device 1 that has used the support server 5 in the past.

By appropriately setting the privilege of the privileged user, it is possible to limit the range that can be deleted for each privileged user.

In the above process, the process of comparing the message file list and the deletion list can be replaced with the process of comparing the difference list and the deletion list and deleting the deletion target message ID.

Next, a typical processing procedure of this embodiment will be described with reference to FIG.

First, the network interface unit 11A of the information processing apparatus A sends a connection request to the information processing apparatus B, and the network interface unit 1 of the information processing apparatus B.
1B performs the acceptance process and establishes a connection between both devices (S31, S41).

Next, the information processing devices A and B respectively create a list 60 of message files stored in the message storage units 12A and 12B, and the user's mail address of each device and the device IDs 131A and 131B.
And also send to the support server 5 (S32, S4
2). At this time, a request for additional services is also made if necessary.

In the support server 5, the arithmetic processing section 52 compares the message file lists (S51). Then, the difference list is created and returned to the information processing apparatuses A and B (S52). The difference list at this time is a type 3 including the shortage list of the information processing apparatus A and the shortage list of the information processing apparatus B.

When the support server 5 receives the request for the additional service, the support server 5 performs the predetermined processing as described above in response to the request. When providing these services for a fee, the billing processing unit 53 performs billing processing.

In the information processing apparatus A, the arithmetic processing unit 15A extracts the difference file which the information processing apparatus B lacks based on the difference list (S33). Similarly, in the information processing apparatus B, the arithmetic processing unit 15B extracts the difference file that the information processing apparatus A lacks based on the difference list (S42). Then, the information processing devices A and B exchange the respective difference files (S34, S43).

When the information processing devices A and B have respectively completed the reception of the difference file, they disconnect each other's connection and the communication is completed (S35, S44).

According to this embodiment, in the P2P communication, the support server can provide various functions to the information processing apparatus with which the support server communicates, thereby providing abundant functions.

The above-described embodiments of the present invention are examples for explaining the present invention, and are not intended to limit the scope of the present invention only to those embodiments. Those skilled in the art can implement the present invention in various other modes without departing from the gist of the present invention.

For example, the support server can be realized integrally with any of the information processing devices capable of performing P2P communication.

[0079]

According to the present invention, it is possible to speed up the processing when an information processing apparatus shares data with another information processing apparatus by P2P.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a network communication system for data sharing according to a first embodiment to which the present invention is applied.

FIG. 2 is a diagram showing a functional configuration of an information processing device.

FIG. 3 is a diagram showing an example of a data structure of a message.

FIG. 4 is a flowchart showing a processing procedure in the first embodiment.

FIG. 5 is a flowchart showing a processing procedure in the first embodiment.

FIG. 6 is a diagram showing a configuration of a network communication system that performs data sharing according to a second embodiment to which the present invention is applied.

FIG. 7 is a diagram showing a functional configuration of a support server.

FIG. 8 is a diagram showing an example of a data structure of a message file list.

FIG. 9 is a diagram showing an example of user information stored in a user information storage unit.

FIG. 10 is a flowchart showing a processing procedure in the second embodiment.

FIG. 11 is a diagram showing an example of a data structure of a history storage unit.

[Explanation of symbols]

1 ... Information processing device, 2 ... Input device, 3 ... Display device, 5 ...
Support server, 11 ... Network interface unit, 12 ... Message storage unit, 13 ... Storage unit, 14 ... Input / output device control unit, 15 ... Arithmetic processing unit, 20 ... Message, 51 ... Network interface unit, 52 ... Arithmetic processing unit, 53 ... Charge processing unit, 54 ... User information storage unit,
55 ... Additional service information storage unit, 56 ... History storage unit.

Claims (10)

[Claims] 1. A method for performing data communication between a first information processing device and a second information processing device, which has a processing performance superior to that of the first information processing device, wherein the first information processing device comprises: The second list of data to be stored
And a process of extracting the first difference data stored in the second information processing device and not stored in the first information processing device, based on the data list. , A data communication method between information processing devices, which includes a process of transmitting the extracted first difference data to the first information processing device. 2. A process of generating a list of second difference data stored in the first information processing device and not stored in the second information processing device, based on the data list, A second information processing device extracted from the first information processing device based on the process of transmitting the second difference data list to the first information processing device and the second difference data list. The data communication method according to claim 1, further comprising: a process of acquiring the differential data of No. 2. 3. A data communication system having a first information processing device and a second information processing device, wherein the second information processing device has a processing performance superior to that of the first information processing device. , The first information processing apparatus is a first information processing apparatus that indicates data stored in the first information processing apparatus.
Means for transmitting the list of No. 1 to the second information processing apparatus, the second information processing apparatus, based on the first data list, means for receiving the first data list, second information Means for extracting first difference data stored in the processing device and not stored in the first information processing device; and means for transmitting the first difference data to the first information processing device. A data communication system provided. 4. The first information processing device receives the difference data list indicating the second difference data stored in the first information processing device and not stored in the second information processing device. And a means for extracting the second difference data based on the difference data list, and a means for transmitting the second difference data to the second information processing apparatus. The data communication system according to claim 3, further comprising: a unit that generates the difference data list based on the first data list; and a unit that transmits the difference data list to a first information processing device. . 5. The first and second information processing devices each hold information indicating the processing performance of the device itself, and either the first or second information processing device stores the information of the respective devices. The data communication system according to claim 3, further comprising a determination unit that determines the superiority or inferiority of the processing performance of the first and second information processing devices based on the information indicating the processing performance. 6. The second extracting means indicates the data stored in the second information processing apparatus.
4. The data communication system according to claim 3, wherein the difference data is extracted by creating a list of, and comparing the first and second lists. 7. A storage unit that stores information indicating the processing performance of its own device, and information indicating the processing performance of the device of the communication partner from the device of the communication partner to obtain the processing performance of the own device and the communication partner. Comparing means for comparing the processing performance of the device of, the result of the comparison, if the processing performance of the own device is superior, obtain a list of data stored by the device of the communication partner, the device of the communication partner stores Information processing apparatus including means for creating a difference list indicating difference data between data to be stored and data stored in the own apparatus, and means for acquiring the difference data from the communication partner apparatus based on the difference list . 8. As a result of the comparison, if the processing performance of the device of the communication partner is superior, means for creating and transmitting a list of data stored in the device itself, and the data stored in the device of the communication partner The information processing apparatus according to claim 7, further comprising: a unit that acquires difference data from data stored in the apparatus. 9. A process for acquiring information indicating the processing performance of the device of the communication partner from the device of the communication partner when executed by a computer, the processing performance of its own device and the processing performance of the device of the communication partner. If the processing performance of the device itself is superior as a result of the comparison process and the comparison result, a list of data stored in the device of the communication partner is acquired, and the data stored in the device of the communication partner and the device itself are stored. A computer program for data communication, which performs a process of creating a difference list indicating difference data with respect to data, and a process of acquiring the difference data from the device of the communication partner based on the difference list. 10. As a result of the comparison, when the processing performance of the device of the communication partner is superior, a process of creating and transmitting a list of data stored in the device itself, The computer program for data communication according to claim 9, further comprising: a process of obtaining difference data from data stored in the device.