JP2009230369A - Synchronization method for shared data, program for synchronizing shared data, and network system for synchronizing shared data to be held - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronization method for a shared data, capable of distributing a load concerned in synchronization processing when a new information processor is joined, in a network system of synchronizing the shared data between a plurality of information processors. <P>SOLUTION: A Node 1 stores a list transmitted from other Node, as an up-to-date list (step S108). The Node 1 copies concurrently a list held by own into a list before updated, at transmission timing of a list transmission request. The Node 1 specifies the shared data of acquisition object, based on a difference between the list before updated and the up-to-date list (step S110). The Node 1 further determines a synchronization mode when acquiring the shared data of acquisition object, based on data information or the like (step S112). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shared data synchronization method, a program for synchronizing shared data among a plurality of information processing apparatuses, and a network system that can hold shared data in synchronization, and in particular, distributes a load related to synchronization processing. For the configuration.

  In the case of sharing data among a plurality of users, a so-called server / client configuration has been conventionally used. The server / client format is a format in which data (files) to be shared is stored in at least one file server, and a plurality of clients access the file server.

  In recent years, instead of such a server / client format, a so-called P2P (Peer to Peer) format configuration is often employed. In this P2P format, files are exchanged at any time between a plurality of information processing devices (each information processing device is also referred to as a “peer” or “node”), thereby synchronizing the same data with each other. The data is shared by this. By adopting such a P2P format, it is not necessary to arrange a file server and manage it. Further, data can be used even when the information processing apparatus is offline.

  On the other hand, in the P2P format, since each information processing apparatus holds data, when the information processing apparatus participates in the network system and tries to acquire data already shared by each information processing apparatus (so-called synchronization) A large number of data is transmitted from a specific information processing apparatus to the participating information processing apparatus. For this reason, the transmission source information processing apparatus may have a problem of consuming a large amount of resources during the execution of the transmission process.

Japanese Patent Laid-Open No. 2004-86800 (Patent Document 1) discloses a communication method by automatically starting data synchronization with an appropriate amount of data transmission so that a large amount of information is not transmitted and received once. A configuration for suppressing the possibility of errors during time increase and data synchronization is disclosed.
JP 2004-86800 A

  However, the configuration disclosed in Japanese Patent Application Laid-Open No. 2004-86800 (Patent Document 1) is mainly applied to the server / client format. In addition, in this configuration, the server stores database update contents as an update history, and adopts a configuration in which data synchronization is started when the number of update histories is greater than a threshold value, so even if applied to a P2P format system The problem that the processing related to data synchronization is concentrated on a specific server is not solved.

  Accordingly, the present invention has been made to solve such a problem, and the object thereof is to provide a case where an information processing apparatus participates in a network system in which shared data is synchronized among a plurality of information processing apparatuses. It is an object of the present invention to provide a shared data synchronization method capable of distributing a load related to synchronization processing. Another object of the present invention is to provide a program for synchronizing the shared data as described above and a network system capable of holding the shared data in synchronization.

  According to an aspect of the present invention, a shared data synchronization method is provided for synchronizing and holding shared data among a plurality of information processing apparatuses capable of data communication with each other. The synchronization method includes a step in which an information processing apparatus to synchronize shared data determines a situation when the synchronization is performed, and an information processing apparatus to synchronize the shared data determines the shared data to be acquired according to the determined situation. Select one of the first mode for acquiring the data from only one other information processing apparatus and the second mode for acquiring the acquisition-target shared data from a plurality of other information processing apparatuses in a distributed manner. A step of determining a previous information processing device, and a step of acquiring information to be acquired from the information processing device determined as the acquisition destination by the information processing device to which the shared data is to be synchronized.

  Preferably, the information processing apparatus holds a list for managing the shared data in addition to the shared data, and the shared data synchronization method is such that the information processing apparatus to synchronize the shared data has other information. The method further includes a step of acquiring a list from the processing device, and in the step of determining the situation, the situation is determined based on the contents of the acquired list.

  More preferably, in the step of determining the situation, the shared data to be acquired is determined based on a difference between a list held by the information processing apparatus to which the shared data should be synchronized and a list acquired from another information processing apparatus. Is done.

  More preferably, the selection between the first mode and the second mode is performed based on the size of the shared data to be acquired.

  Preferably, in the step of determining the situation, the situation is determined based on a response time from another information processing apparatus.

  Preferably, in the step of determining the situation, the situation is determined based on the magnitude of the data transmission rate of the response from another information processing apparatus.

  Preferably, the plurality of information processing apparatuses constitutes a network, and in the step of determining the situation, the situation is determined based on a length of a period during which the information processing apparatus to which the shared data is to be synchronized is disconnected from the network. Is done.

  Preferably, in the step of determining the information processing apparatus as the acquisition destination, when the first mode is selected, the candidate information processing apparatus with the fastest response is determined as the information processing apparatus as the acquisition destination.

  Preferably, in the step of determining the information processing apparatus as the acquisition destination, the information processing apparatus as the acquisition destination is determined with information processing apparatuses close to the information processing apparatus that should synchronize the shared data on the communication path as candidates.

  Preferably, in the step of determining an information processing apparatus as an acquisition destination, when the second mode is selected, a candidate group including information processing apparatuses close to the information processing apparatus that should synchronize the shared data on the communication path; Then, after distinguishing it from a candidate group consisting of other information processing devices, the acquisition destination of each shared data is selected from either one of the candidate groups according to the data information of the shared data to be acquired. The

  More preferably, the information processing apparatus close to the information processing apparatus that should synchronize the shared data includes an information processing apparatus that can receive a broadcast message from the information processing apparatus that should synchronize the shared data.

  More preferably, each of the information processing apparatuses has a network address including a network number and a host number, and the information processing apparatus close to the information processing apparatus to which the shared data should be synchronized should synchronize the shared data. An information processing apparatus having the same network number as the network number of the information processing apparatus is included.

  Preferably, the information processing apparatus to synchronize the shared data further includes a step of storing the acquired shared data in its own storage unit and updating the contents of the list.

  According to another aspect of the present invention, a program for synchronizing shared data among a plurality of information processing apparatuses connected so as to be capable of data communication with each other is provided. When the shared data should be synchronized with the information processing apparatus, the program determines the situation at that time, and acquires the shared data to be acquired from only one other information processing apparatus according to the determined situation Selecting one of a first mode to perform and a second mode for acquiring shared data to be acquired from a plurality of other information processing devices in a distributed manner, and determining an information processing device as an acquisition destination; And acquiring shared data to be acquired from the information processing apparatus determined as the acquisition destination.

  According to still another aspect of the present invention, a network system capable of holding shared data in synchronization among a plurality of information processing apparatuses capable of data communication with each other is provided. The information processing apparatus that should synchronize the shared data has a means for determining a situation when synchronizing the shared data, and acquires the shared data to be acquired from only one other information processing apparatus according to the determined situation. Means for selecting one mode and a second mode in which shared data to be acquired is acquired in a distributed manner from a plurality of other information processing devices, and determining an information processing device as an acquisition destination; Means for acquiring shared data to be acquired from the information processing apparatus determined as.

  According to the present invention, in a network system in which shared data is synchronized among a plurality of information processing apparatuses, synchronization of shared data capable of distributing a load related to synchronization processing when the information processing apparatus participates Is to provide a method.

  Embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment]
(Overall configuration of network system)
FIG. 1 is a schematic configuration diagram of a network system SYS according to an embodiment of the present invention.

  Referring to FIG. 1, network system SYS according to the present embodiment includes hierarchical routers RT1, RT2 and RT3, and a plurality of information processing devices PC1 to PC7 can communicate data with each other via these routers. Suppose that it is configured to a state. The plurality of information processing apparatuses PC1 to PC7 hold at least one shared data in synchronization according to a communication protocol of P2P (Peer to Peer) format.

  More specifically, the router RT2 and the router RT3 are connected to the uppermost router RT1, and the information processing devices PC1 to PC4 are connected to the ports of the router RT2, respectively. Are connected to information processing apparatuses PC5 to PC7. Each of the routers RT1 to RT3 and the information processing apparatuses PC1 to PC7 is assigned a network address (typically an IP address) including a network ID (network number) and a host ID (host number). In particular, the router RT2 and the information processing devices PC1 to PC4 connected to the router RT2 are assigned the same network ID, and the information processing devices PC5 to PC7 connected to the router RT3 and the router RT3 The same network ID is assigned to each other. Note that the network ID assigned to the router RT2 and the like and the network ID assigned to the router RT3 and the like are different from each other, and both can be logically identified. Of the network addresses, the network ID and the host ID are distinguished based on the value of the netmask.

  In this specification, “synchronization” means a state where each of a plurality of information processing apparatuses holds the same shared data without excess or deficiency. That is, each information processing apparatus collects shared data to be acquired by exchanging data (data copying) with other information processing apparatuses. By repeating such processing, each of the information processing apparatuses PC1 to PC7 included in the network system SYS can hold the same shared data without excess or deficiency. Note that the shared data is typically determined by a user newly generating using any personal computer or designating generated data as shared data.

  In the present embodiment, a specific information processing device (typically referred to as information processing device PC1 in the following description) has temporarily left (offline) from the network system SYS with respect to the network system SYS at a certain point in time. Later, a synchronization process in the case of rejoining (online) the network system SYS after a considerable period of time will be described.

  In the shared data synchronization method according to the present invention, an information processing device that does not hold all or part of the shared data in a network system SYS in which a plurality of information processing devices hold shared data in synchronization, that is, synchronization. It is directed to processing when an information processing apparatus that does not completely hold shared data in a state participates. Therefore, in addition to the case where the information processing apparatus that has participated in the network system SYS once leaves and rejoins as described in the present embodiment, a completely new information processing apparatus participates in the network system SYS. It is also applicable to cases where

  In this embodiment, a configuration using a personal computer is illustrated as a representative example of the information processing apparatuses PC1 to PC7 (hereinafter also collectively referred to as “information processing apparatus PC”), but a communication protocol and application in the P2P format can be implemented. Any device may be used as long as it is a simple device. More specifically, as the information processing apparatus PC, an MFP (Multi Function Peripheral), a mobile phone, a PDA (Personal Digital Assistance), a network facsimile, or the like equipped with a copying function or a facsimile function can be adopted.

  Further, the information processing apparatuses PC do not necessarily have to be physically connected to the same layer network as long as they can logically communicate with each other.

(Hardware configuration)
FIG. 2 is a schematic diagram showing a schematic hardware configuration of a personal computer which is a representative example of information processing apparatuses PC1 to PC7 according to the embodiment of the present invention.

  Referring to FIG. 2, information processing device PC according to the present embodiment includes a CPU 200 that executes various programs including an operating system, and a memory unit 212 that temporarily stores data necessary for the execution of the programs by CPU 200. And a hard disk unit (HDD) 210 that stores a program executed by the CPU 200 in a nonvolatile manner. Such a program is read from a CD-ROM 214a or a flexible disk 216a by a CD-ROM (Compact Disk-Read Only Memory) drive 214 or a flexible disk (FD: Flexible Disk) drive 216, respectively.

  The CPU 200 receives a user operation request via the input unit 208 such as a keyboard or a mouse, and outputs a screen output generated by executing the program to the display unit 204. The CPU 200 performs data communication with other information processing apparatuses via a network interface (I / F) unit 206 including a LAN card. These parts are connected to each other via the internal bus 202.

(Functional configuration of information processing device)
FIG. 3 is a schematic diagram showing a control structure in information processing apparatuses PC1 to PC7 according to the embodiment of the present invention. In the control structure shown in FIG. 3, the CPU 200 (FIG. 2) typically develops a program stored in the hard disk unit 210 (FIG. 2) in the memory unit 212 (FIG. 2) and executes each command. Provided.

  Referring to FIG. 3, each of the information processing apparatuses PC includes a data receiving unit 102, a data analyzing unit 104, a data operation unit 106, a list management unit 108, an authentication unit 110, a network application unit 112, The connection table management unit 114, the mode determination unit 118, the data storage unit 120, the data creation unit 122, and the data transmission unit 124 are included as functions. The data storage unit 120 is realized by securing a predetermined area in the hard disk unit 210 (FIG. 2).

  The data receiving unit 102 receives a data packet transmitted over the network NW, combines the dividedly transmitted data packets, restores them to a data string, and outputs them to the data analyzing unit 104. The data analysis unit 104 analyzes the contents of each data string (typically, address information of the header part), and determines whether or not the data string is addressed to the own apparatus. Then, the data analysis unit 104 selects only the data string determined to be destined for the own device from the data operation unit 106, the list management unit 108, the authentication unit 110, the network application unit 112, and the connection table management unit 114. To output.

  When the user newly generates data in the own information processing apparatus PC, or when new data is transmitted from another information processing apparatus PC, the data operation unit 106 transmits the data to the shared data in the data storage unit 120. The contents are stored in the holding unit (DB) 116 and changed contents such as addition or deletion of the shared data are notified to the list management unit 108. Further, the data operation unit 106 provides shared data stored in the shared data holding unit 116 in response to a request from another information processing apparatus PC.

  In addition, when the information processing device PC participates in the network system SYS, the data operation unit 106 follows the instruction of the list management unit 108 to be described later about the shared data specified by the specified other information processing device PC. Send a data transmission request. Further, when receiving the shared data transmitted in response to the data transmission request from the other information processing apparatus PC, the data operation unit 106 stores the data in the shared data holding unit 116 of the data storage unit 120 and the shared data The list management unit 108 is notified of data reception and storage.

  When the list management unit 108 receives the notification of the change of the shared data from the data operation unit 106 described above, the list management unit 108 updates the list 134 of the data storage unit 120 based on the content. The list 134 includes data for managing shared data stored in the shared data holding unit 116 of the data storage unit 120. More specifically, the list 134 includes, in addition to the shared data stored in the shared data holding unit 116, the data name (or file name), size, update date / time, creation date / time, importance, file of the shared data. The type, data creator, accessible user (or access control information), and other attribute information are included. An example of the list 134 will be described later.

  When the list management unit 108 receives a list transmission request from the information processing apparatus PC that has participated in the network system SYS via the network application unit 112 described later, the list management unit 108 receives the list 134 stored in the data storage unit 120. To the information processing apparatus PC.

  In addition, when the information processing apparatus PC participates in the network system SYS, the list management unit 108 copies the list 134 at the time of participation to the pre-update list 136 and the list 134 transmitted by the other information processing apparatus PC. Is stored in the data storage unit 120 as the latest list 138. Further, the list management unit 108 identifies the acquisition target shared data based on the difference between the pre-update list 136 and the latest list 138. Then, an instruction for acquiring the shared data to be acquired is given to the mode determination unit 118 and the data operation unit 106. That is, the list management unit 108 synchronizes the shared data with the information processing apparatus PC belonging to the network system SYS based on the list 134 (the latest list 138 of the own information processing apparatus PC) held by the other information processing apparatus PC. To do.

  The mode determination unit 118 determines a synchronization mode for acquiring the acquisition target shared data based on data information such as the number and total size of the acquisition target shared data necessary for synchronization. More specifically, the mode determination unit 118 includes “single mode” in which shared data is acquired from one information processing device PC, and “multiple mode” in which shared data is acquired in a distributed manner from a plurality of information processing devices PC. Is configured to be selectable. The “single mode” is a mode in which the shared data is acquired from one information processing apparatus PC that is close on the communication path mainly when the shared data to be acquired is relatively small. The “multiple mode” is mainly This is a mode for acquiring shared data in a distributed manner from a plurality of information processing apparatuses PC when there is a relatively large amount of shared data to be acquired. The processing related to the determination of the synchronous mode and the processing in each mode will be described later. The determination result of the synchronization mode determined by the mode determination unit 118 is output to the data operation unit 106.

  The authentication unit 110 determines connection refusal for access from another information processing apparatus PC. More specifically, the authentication unit 110 rejects the connection by performing an authentication process based on the user ID and password attached to the access request of the other information processing apparatus PC or the apparatus ID of the other information processing apparatus PC. to decide. Alternatively, a black list and / or a white list is stored in advance, and connection to the information processing apparatus PC that is the source of the access request is permitted only when the black list does not correspond to the white list or the white list. May be.

  The network application unit 112 transmits an access request to another information processing apparatus PC belonging to the network system SYS when the information processing apparatus PC intends to participate in the network system SYS in response to a user operation or the like. In addition, when the information processing apparatus PC tries to leave the network system SYS in response to a user operation or the like, the network application unit 112 transmits a leave notification to another information processing apparatus PC belonging to the network system SYS. .

  The data creation unit 122 shapes the shared data read by the data operation unit 106, the list 134 read by the list management unit 108, the access request issued by the network application unit 112, and the like into a predetermined data packet, and the data transmission unit 124 Output to.

  The data transmission unit 124 refers to the connection table 132 of the data storage unit 120, acquires unique information (typically, a network address such as an IP address) for specifying the transmission destination of each data packet, and Transmit via NW.

  The connection table 132 stores information for specifying the information processing apparatuses PC1 to PC7 included in the network system SYS. Specifically, the connection table 132 includes an IP address, a MAC address, a netmask, and the like in addition to at least the information processing apparatus PC configuring the P2P format network system SYS.

  When any information processing apparatus PC newly joins the network system SYS, or when any information processing apparatus PC leaves the network system SYS, the connection table management unit 114 connects the connection table of the data storage unit 120. The contents of 132 are updated.

(Synchronization process when participating)
First, with reference to FIG. 4 to FIG. 7, processing that is commonly executed when an information processing apparatus participates in the network system SYS according to the present embodiment will be described. In the following description, as an example, a description will be given of a synchronization process when the information processing apparatus PC1 once leaves (offline) from the network system SYS and rejoins (online) the network system SYS after a considerable period of time has elapsed.

  In the following description, paying attention to logical connections between information processing apparatuses PC that are logically formed, the information processing apparatuses PC1 to PC7 are also referred to as “Node (or nodes) 1 to Node7”, respectively.

  FIG. 4 is a diagram illustrating a state of the network system SYS immediately before Node 1 leaves. FIG. 5 is a diagram illustrating a state of the network system SYS immediately after Node1 rejoins.

  As shown in FIGS. 4 and 5, as an example, it is assumed that the network address of the router RT1 is “10.100.1.100” and the network address of the router RT2 is “10.100.2.100”. The network address of the router RT3 is assumed to be “10.100.3.100”. In the present embodiment, among these network addresses, “10.100.1”, “10.100.2”, and “10.100.3” at the head portion indicate the network ID, and “100” in the latter half portion. "Indicates a host ID. Of the network addresses of Node 1 to Node 4, the network ID is the same as the network ID of the router RT2 that is the connection destination (ie, “10.100.2”), and the host ID is set to a unique value. Suppose that Similarly, among the network addresses of Node5 to Node7, the network ID is the same as the network ID of the router RT3 that is the connection destination (ie, “10.100.3”), and the host ID is set to a unique value. Suppose that

  By the way, since the broadcast message transmitted from any one of the nodes is transferred to a device having the same network ID, when a network configuration as shown in FIGS. The transmitted broadcast message is transferred only to the router to which the Node is connected and to other Nodes commonly connected to the router. As an example, a broadcast message transmitted from Node1 is transferred to Node2, Node3, and router RT2, but is not transferred to Node5 to Node7 and routers RT1, RT2.

  Referring to FIG. 4, assume that Node 1 to Node 7 hold data A and data B in synchronization as an initial state. Each of Node 1 to Node 7 also holds a list for managing these data. In the state shown in FIG. 4, it is assumed that Node 1 is changed from online to offline in response to a user operation or the like, and then a state after a considerable period of time has passed is shown in FIG.

  Referring to FIG. 5, shared data held in synchronization in network system SYS is added in a period in which Node 1 is offline, and data A to data are shared between other Nodes except Node 1 that is offline. Assume that a total of 6 shared data of F are synchronized. As the shared data is added, the contents of the list held by each of Node 2 to Node 7 are also updated, so that the contents of the list held by Node 1 are different.

  In such a state, a description will be given of the shared data synchronization processing when Node 1 is changed from offline to online and rejoins the network system SYS.

  FIG. 6 is a diagram illustrating a process executed immediately after Node1 rejoins. FIG. 7 is a diagram showing a state of the network system SYS after the execution of the processing shown in FIG.

  Referring to FIG. 6, Node 1 that rejoined first transmits a list transmission request to another Node. The list transmission request may be transmitted to at least one Node. Further, the transmission method may be direct transmission to a specific node, broadcast transmission that transmits to a node having the same network ID at a time, or multicast transmission that specifies a plurality of specific nodes. Good.

  Any other Node that has received this list transmission request returns its own list to Node 1 that is the list transmission request source. When the list transmission request is broadcast, the transmission destination does not need to be known, and the existing Node may be confirmed based on the list returned in response to the list transmission request. In this case, Node 1 can receive a plurality of lists, but it is only necessary to store only the list with the latest update date.

  Referring to FIG. 7, Node 1 copies the list held at that time as the pre-update list, along with the transmission of the list transmission request. This pre-update list serves as a reference for specifying the shared data to be acquired (to be synchronized), and it is preferable to prohibit overwriting at the same time as copying. Node1 stores the list received from the other Node as the latest list.

  FIG. 8 is a diagram illustrating an example of a list held by Node1. FIG. 8A shows an example of the pre-update list (list immediately after rejoining), and FIG. 8B shows an example of the latest list acquired from another Node.

  As shown in FIG. 8, attribute information such as “data name”, “size”, and “update date / time” is defined for each of the list, the pre-update list, and the latest list, in addition to the shared data held in synchronization. Suppose that These pieces of attribute information are generated or added when shared data to be synchronized is added. The attribute information stored in the list is not limited to such information, and may include other attribute information such as “importance”.

  When Node 1 receives a list from another Node, Node 1 specifies shared data to be acquired based on the difference between the pre-update list (FIG. 8A) and the latest list (FIG. 8B). In the example illustrated in FIG. 8, it is specified that data C to data F are shared data to be acquired. Then, Node 1 determines whether to acquire these shared data in “single mode” or “multiple mode” based on data information such as the number of shared data to be acquired and the total size. .

(Synchronous mode selection process)
Hereinafter, the selection processing of “single mode” and “multiple mode” will be described.

  As described above, the synchronization mode can be selected based on the data information such as the number of shared data to be acquired and the total size, but in this embodiment, based on the total size of the shared data to be acquired. An example of a method for determining the synchronization mode will be described.

  Specifically, the synchronization mode is determined based on the ratio of the total size of the shared data to be acquired to the size of the storage area of the shared data holding unit 116 (FIG. 3) of the data storage unit 120. This is because the size of the shared data holding unit 116 (FIG. 3) is considered to be set according to the capability of each Node, so by comparing the acquisition target shared data with reference to the capability of each Node, The number of nodes from which shared data is acquired is determined.

  In the present embodiment, as an example, the threshold of this ratio is 20%. Therefore, for example, if the shared data holding unit 116 of the data storage unit 120 has a storage area of 10,000 KB, the “single mode” if the total size of the shared data to be acquired is less than 2,000 KB. Is selected, and the “multiple mode” is selected if the total size of the shared data to be acquired is 2,000 KB or more.

  In the example shown in FIG. 8, the total size of the shared data to be acquired is 1,880 KB, and “single mode” is selected under the above conditions.

  As a matter of course, it is preferable to set the above-mentioned ratio threshold value to an appropriate value in consideration of the network environment and each Node environment. The synchronization mode may be selected based on other data information such as the number of shares to be acquired, the file type, the number of accesses, and the importance.

(Single mode)
“Single mode” is a mode in which shared data to be acquired is acquired from any one node. In particular, the present embodiment is a mode in which shared data of an acquisition destination is acquired from a candidate group including a Node that requests shared data and a Node that is adjacent on the communication path. In addition, as a method for specifying a neighboring node on a communication path, it can be determined based on a known network address. However, in this embodiment, a range in which a broadcast message reaches (that is, the network ID is the same). Nodes in are identified as neighboring Nodes.

  Furthermore, in the present embodiment, when there are a plurality of adjacent Nodes, the Node having the highest processing capacity (or the most leeway) at each time point is identified, and the acquisition target is determined from the identified Node. Get shared data. More specifically, a specific command (typically, a ping command) is transmitted from the node that acquires the shared data to each candidate node, and the one with the earliest response is acquired in the single mode. Decide as a destination.

  FIG. 9 is a diagram for explaining processing for determining a shared data acquisition destination in the single mode. FIG. 10 is a diagram for explaining processing during acquisition of shared data in the single mode. FIG. 11 is a diagram illustrating a state in which the shared data acquisition process in the single mode is completed.

  Referring to FIG. 9, when Node 1 determines that the synchronization mode of the shared data to be acquired is “single mode”, Node 1 transmits a ping command to Node 2, Node 3, and Node 4 having the same network ID. In addition, when a Node having the same network ID is not known, a broadcast message is transmitted from Node 1, and a Node having the same network ID may be specified based on a response to the broadcast message.

  Each of Node 2, Node 3, and Node 4 that has received the ping command from Node 1 transmits a predetermined response to Node 1. Node 1 measures the time until a response is received from each of Node 2, Node 3, and Node 4 after transmitting the ping command, and identifies the Node with the fastest response. As an example, if the order of responses to the ping command is Node2, Node3, and Node4, Node1 determines Node2 as the acquisition source of shared data in the single mode.

  When the acquisition destination of the shared data is determined in this way, Node1 transmits a request for transmission of the acquisition-target shared data to Node2, as shown in FIG. When the node 2 receives the data transmission request from the node 1, the node 2 reads the specified shared data and sequentially transmits the read shared data to the node 1.

  Node 1 stores the shared data transmitted from Node 2 in its own shared data holding unit 116 (FIG. 3), and updates the contents of the list for managing the shared data.

  When the series of processes as described above is completed, the network system SYS is in a state as shown in FIG. When all the shared data to be acquired is stored, Node 1 deletes or invalidates the pre-update list and the latest list.

  As shown in FIG. 8, when there are a plurality of pieces of shared data to be acquired, the target shared data may be acquired by any method of batch acquisition, divided acquisition, and sequential acquisition. In addition to the case where these transmission methods are determined in advance, an optimal method may be dynamically determined according to the network environment and the Node environment (CPU, frequency of use, etc.). In addition, the order in which shared data is acquired sequentially is determined appropriately based on the data information of the shared data, such as the most recent update date, the most important order, and the most frequently accessed user. May be. Alternatively, the node from which the data is acquired may be uniquely determined.

  In the above example, the method of determining the node from which data is acquired based on the speed of response to a specific command is illustrated, but the determination is made based on the network environment, the node environment, the user access status (usage status, etc.), etc. May be. Alternatively, the user may manually determine the data acquisition node. Furthermore, a plurality of methods as described above may be combined and determined.

(Multiple mode)
“Multiple mode” is a mode in which shared data to be acquired is acquired in a distributed manner from a plurality of Nodes.

  FIG. 12 is a diagram illustrating another example of the list held by the Node. FIG. 12A shows an example of a pre-update list (list immediately after rejoining), and FIG. 12B shows an example of the latest list acquired from another Node.

  The content of the latest list shown in FIG. 12B is obtained by changing the update date and time for data B as compared to the latest list shown in FIG. That is, FIG. 12B illustrates a case where data C to data F are added as shared data and data B is updated in a period in which Node1 is offline.

  According to the difference between the pre-update list (FIG. 12A) and the latest list (FIG. 12B), the added data C to F are shared data to be acquired due to the difference in data names. The data B is specified as the acquisition target shared data based on the difference in the update date and time (or size).

  In the example shown in FIG. 12, the total size of the shared data to be acquired is 3,559 KB, and the ratio is 35.59%. Therefore, “multiple mode” is selected under the above conditions.

  When “multiple mode” is selected, Node 1 determines a plurality of Nodes from which shared data is acquired. The acquisition destination candidates can be all Nodes belonging to the same network system SYS. For these candidates, the acquisition destinations of the acquisition target shared data can be distributed to the candidate Nodes in a predetermined order, whereby the acquisition destinations can be distributed.

  In particular, when the number of candidate nodes is large compared to the number of pieces of shared data to be acquired as in the present embodiment, a more appropriate process is performed according to the procedure shown below among the candidate nodes. It is preferable to determine the source of the shared data.

  First, Node1 rearranges the contents of the latest list. The rearrangement here is performed so that the size of each data is in descending order. This is because the acquisition destination Node is determined based on the size of the shared data to be acquired.

  More specifically, based on a predetermined threshold, the shared data is relatively large (size is greater than or equal to the threshold) and the size is relatively small (size is less than the threshold). ) Distinguish from shared data, and share data with a relatively large size is obtained from one of the candidate groups consisting of adjacent Nodes. Obtained from one of candidate groups consisting of Nodes (remote Nodes). As a result, for shared data with a large network load, the transmission distance is relatively small, and for shared data with a small network load, the transmission distance is relatively large, so that the entire network system SYS The load balance can be adjusted.

  The determination of proximity or remote in the network can be made based on the network address (network ID). That is, Node 2 to Node 4 connected to the same router RT 2 as Node 1 can be determined as neighboring Nodes, and Node 5 to Node 7 connected to a router RT 3 different from Node 1 can be determined as remote Nodes. Alternatively, it is possible to transmit a broadcast message and determine that a node that is within a reachable range (that is, the same network ID) is a neighboring node.

  FIG. 13 is a diagram illustrating a state after rearrangement of the latest list illustrated in FIG. The list shown in FIG. 13 is obtained by rearranging the latest list shown in FIG. 12B based on the size, and the files are arranged in order from the largest size. Note that the data A that is not the acquisition target is not the rearrangement target.

  In the latest list after rearrangement shown in FIG. 13, when the predetermined threshold is 1,000 KB, data B and data E exceeding the threshold are acquired from any of the adjacent Node groups, The other data F, data C, and data D are determined to be acquired from any of the remote node groups.

  As described above, when the data to be acquired from the neighboring Node group (Node 2 to Node 4) and the remote Node group (Node 5 to Node 7) are distinguished, Node 1 transmits shared data to any Node of each Node group. Decide whether to request. More specifically, a specific command (typically, a ping command) is transmitted to each node included in each node group in the same manner as the acquisition destination node is determined in the single mode described above. And based on the speed of the response, the acquisition destination is dynamically determined from each Node group.

  As an example, assuming that the order of responses to the ping command in the neighboring Node group is Node2, Node3, and Node4, Node1 sets Node2 as data B according to the arrangement order (FIG. 13) of the data assigned to the neighboring Node. And Node3 is determined as the data E acquisition source. On the other hand, if the order of responses to the ping command in the remote Node group is Node5, Node6, and Node7, Node1 sets Node5 as the acquisition destination of data F according to the arrangement order of the data assigned to the remote Node. Then, Node 6 is determined as the acquisition destination of data C, and Node 7 is determined as the acquisition destination of data D.

  In the above-described example, the method for determining the node of the data acquisition destination in each Node group based on the speed of response to a specific command is exemplified, but the network environment, Node environment, user access status (usage status, etc.), etc. You may judge based on. Alternatively, the user may manually determine the data acquisition node. Furthermore, a plurality of methods as described above may be combined and determined.

  FIG. 14 is a diagram for explaining processing for requesting transmission to each Node in a plurality of modes. FIG. 15 is a diagram for describing processing for acquiring shared data from each Node in a plurality of modes.

  Referring to FIG. 14, when the acquisition destination for the acquisition target shared data is determined according to the above-described processing, Node 1 transmits a shared data transmission request to each of the acquisition destination Nodes. As illustrated in FIG. 15, each Node that has received the data transmission request reads the specified shared data and transmits the read shared data to Node 1.

  Node 1 sequentially stores the shared data transmitted from each node of the acquisition destination in its own shared data holding unit 116 (FIG. 3), and updates the contents of the list for managing the shared data.

  When the series of processes as described above is completed, the network system SYS is in a state as shown in FIG. When all the shared data to be acquired is stored, Node 1 deletes or invalidates the pre-update list and the latest list.

  In addition, when there are a plurality of pieces of shared data requested from each node, the target shared data may be acquired by any one of collective acquisition, divided acquisition, and sequential acquisition.

  In addition, a data transmission request to which instruction information indicating the transmission timing of the target shared data is added may be transmitted to each of the acquisition destination Nodes. That is, it is possible to specify the transmission timing from each acquisition destination Node so that Node 1 can receive the shared file in a predetermined order. By shifting the timing in this way, it is possible to suppress a rapid increase in load in the network system SYS.

  Further, when the size of the shared data is large, it may be requested to transmit after dividing one shared file into a plurality of pieces.

(Processing procedure)
The above processing can be summarized as a processing sequence as shown in FIG.

FIG. 16 is a sequence diagram relating to the synchronization processing according to the embodiment of the present invention.
Referring to FIG. 16, when the user operates Node1 to rejoin the network system SYS (Step S100), Node1 creates a list transmission request (Step S102) and sends it to another Node of the network system SYS. The created list transmission request is transmitted (step S104).

  In response to this list transmission request, at least one Node configuring the network system SYS transmits a list held by the Node itself to Node 1 (Step S106).

  Node1 stores the list transmitted from the other Node as the latest list (step S108). At the same time, Node 1 copies the list held by itself at the transmission timing of the list transmission request to the pre-update list. Then, Node 1 identifies the shared data to be acquired based on the difference between the pre-update list and the latest list (step S110). Further, Node 1 determines a synchronization mode for acquiring the acquisition target shared data based on data information such as the number of acquisition target shared data and the total size (step S112).

  When “single mode” is selected in step S112, Node1 transmits a ping command to each candidate node to which the shared data transmission is requested (step S120). When each candidate Node receives this ping command, it transmits a response to Node 1 (Step S122).

  Node 1 measures the time until a response is received from each of the candidate nodes after transmitting the ping command, and determines the node with the fastest response as the transmission request destination node (step S124).

  After determining the transmission request destination Node, Node 1 transmits a data transmission request designating corresponding shared data to the transmission request destination Node (step S126). In response to this data transmission request, the transmission request destination Node reads the designated shared data held by itself and transmits the read shared data to Node 1 (step S128).

  The Node 1 that has received the shared data from the transmission request destination Node stores the shared data in its own shared data holding unit 116 (FIG. 3) (step S130). Node 1 updates the contents of the list for managing the shared data.

  On the other hand, when “multiple mode” is selected in Step S112, Node 1 sorts the contents of the latest list, and then classifies the shared data to be acquired into a proximity Node group and a remote Node group, and for each group, The candidate node of the transmission request destination is determined (step S140). Further, Node 1 transmits a ping command to each candidate node of the shared data transmission request destination for each Node group (step S142). When each candidate Node receives this ping command, it transmits a response to it to Node 1 (step S144).

  After transmitting the ping command, Node 1 measures the time until receiving a response from each of the candidate Nodes, and determines the node with the fastest response as the transmission request destination Node for each Node group (step S146).

  After determining the transmission request destination Node, Node 1 transmits a data transmission request specifying the corresponding shared data to the transmission request destination Node, respectively (step S148). In response to each data transmission request, the transmission request destination Node reads the designated shared data held by itself, and transmits the read shared data to Node 1 (step S150).

  The Node 1 that has received the shared data from the transmission request destination Node stores the shared data in its own shared data holding unit 116 (FIG. 3) (step S152). Node 1 updates the contents of the list for managing the shared data.

(Shared data addition process)
Next, a process for adding shared data held in network system SYS according to the present embodiment will be described with reference to FIG.

  In the following description, as an example, a case where data G is added to Node 2 as shared data when the network system SYS is in the state shown in FIG.

  FIG. 17 is a sequence diagram relating to shared data addition processing according to the embodiment of the present invention.

  Referring to FIG. 17, when data G is generated at Node 2 or given to Node 2 by a user operation or the like, Node 2 stores the data G in its own shared data holding unit 116 (FIG. 3). (Step S200) and update or generate a list for managing the shared data (step S202). That is, Node 2 adds an entry for data G to its list. Furthermore, Node2 transmits an update message to each of the other Node3 to Node7 (Step S204), and notifies that shared data has been added.

  Each of Node3 to Node7 that has received this update message generates a transmission request for the updated data (step S206), and transmits the generated data transmission request to Node2 (step S208). When Node 2 receives a data transmission request from any one of Node 3 to Node 7, Node 2 reads data G stored in its own shared data holding unit 116 (FIG. 3) and generates a difference in a list corresponding to data G. (Step S210). Furthermore, Node2 transmits the data G and the list difference to the node (Node3 to Node7) that is the transmission source of the data transmission request (step S212).

  The Nodes (Node 3 to Node 7) that have received the data G and the list difference store the data G in their shared data holding unit 116 (FIG. 3) (step S214) and list the list for managing the shared data Update according to the difference (step S216). Each Node that has completed Step S214 and Step S216 transmits a data update completion notification to Node 2 (Step S218).

  In step S204 and step S208 described above, an update message is transmitted from the transmission node (Node 2) to the reception nodes (Node 3 to Node 7), and is added only when the transmission node receives a data transmission request from the reception node. The transmission of the shared data is started because the shared data is not forcibly transmitted to the receiving node when new shared data cannot be added, such as when the receiving node is in a high load state. Therefore, after transmitting an update message from Node2, for other Nodes that could not receive the data transmission request, Node 2 manages the elapsed time from the transmission of the update message, and the Node that cannot receive the data transmission request even after a lapse of a corresponding time. For Node 2, the update message is retransmitted (step S220).

  Note that instead of the configuration in which the update message is retransmitted as in step S220 described above, the node 2 may continue to wait until it receives data transmission requests from all other nodes.

  Further, in the above-described steps S210 and S212, the configuration in which the list difference for the shared data to which Node2 has been added is transmitted to other Nodes is illustrated, but the updated list, that is, Node2 after data G has been added is retained. The list itself may be transmitted to another Node. Or in each Node which receives the data G added from Node2, when updating the content of the list about the shared data, it is not necessary to transmit the list difference or the list itself. In the present embodiment, a configuration including the importance of shared data as a list item is adopted. In such a case, when data G is transmitted from Node2, attribute information (importance) of the shared data is transmitted. May be added to the data G and transmitted to each Node. Then, the list may be updated based on the attribute information added to the data G at each Node that has received the data G.

(Conflict between synchronous processing and shared data addition processing)
In the above description of the synchronization process, it is assumed that no shared data is added during the process, but these processes may conflict. That is, in the network system SYS shown in FIG. 5, processing when Node 1 receives an update message as shown in step S <b> 204 in FIG. 17 in a state where shared data synchronization processing is executed after Node 1 rejoins. explain.

  As an example of processing in the case of such a conflict, Node 1 completes the shared data synchronization processing based on the pre-update list and the latest list acquired before receiving the update message, and then step S208 in FIG. A data transmission request as shown in FIG. Since the list difference is transmitted from Node 2, Node 1 acquires necessary shared data based on the list difference.

  As another example of processing in the case of contention in this way, Node 1 transmits a data transmission request to Node 2 as soon as possible when it receives an update message. And Node1 acquires required shared data in parallel based on the temporary list acquired before receiving the update message and the list difference received from Node2. At this time, it is preferable to adjust the amount of data requested to be transmitted to another node according to the network status and the load status of the data transmission request destination node. In addition, when the shared data is acquired after updating the temporary list based on the list difference, it is preferable to rearrange the updated temporary list and re-determine the transmission request destination.

  As described above, in the process of adding shared data, when the list itself is transmitted, the latest list is distributed when any shared data is added, so steps S102 and S104 in FIG. The creation and transmission of a list transmission request as shown in FIG. By reducing the processing in this way, the efficiency can be further increased.

(Effect in embodiment)
According to an embodiment of the present invention, when an information processing apparatus participates in a network system that synchronizes shared data among a plurality of information processing apparatuses, the shared data to be acquired for synchronization is added. In response, the information processing apparatus as the acquisition destination can be dynamically determined to be either single or plural. When acquiring shared data from a single information processing device, the synchronization process can be completed quickly, whereas when acquiring shared data from a plurality of information processing devices, it is related to the synchronization processing in the network system. The load concentration can be avoided. Therefore, it is possible to avoid the load related to the synchronization process from being concentrated on a specific information processing apparatus.

  Further, according to the embodiment of the present invention, based on data information such as the size of shared data, relatively large size shared data is acquired from an information processing apparatus adjacent to the information processing apparatus that requires the shared data. On the other hand, relatively small-sized shared data is acquired from an information processing apparatus that is remote from the information processing apparatus that requires the shared data. Thereby, the load balance as the whole network system can be adjusted.

[First Modification of Embodiment]
In the above-described embodiment, the configuration in which the synchronization mode is determined based on the number of shared data to be acquired and the like is illustrated. However, in the following, the configuration in which the state of the network system SYS is taken into account when determining the synchronization mode. Illustrate. The schematic configuration of network system SYS according to the first modification of the embodiment of the present invention is the same as that of FIG. 1, and the hardware configuration and control structure of information processing apparatus PC are the same as those of FIGS. Therefore, detailed description will not be repeated.

  In the first modification, as in the above-described embodiment, when Node 1 rejoins the network system SYS, Node 1 acquires the pre-update list 136 and the latest list 138 (similar to FIG. 7).

  After the state shown in FIG. 7 is reached, Node 1 transmits a ping command to all the Nodes constituting the network system SYS. And Node1 measures the response time until it receives a response from each Node after transmission of a ping command, respectively. It is assumed that the amount of response data is the same.

  If the measured response time for each Node is less than a predetermined target value, Node 1 determines the synchronization mode as “single mode”. Then, the node having the shortest response time is designated as the shared data transmission request destination. In other cases, the synchronization mode is determined as “multiple modes”.

  Since other processes are the same as those in the above-described embodiment, detailed description will not be repeated.

  According to the first modification of the embodiment of the present invention, the synchronization mode and the transmission request destination can be determined more reflecting the state of the network system SYS.

[Second Modification of Embodiment]
In the above-described embodiment, the configuration in which the synchronization mode is determined based on the number of shared data to be acquired and the like is illustrated. However, in the following, the configuration in which the state of the network system SYS is taken into account when determining the synchronization mode. Illustrate. The schematic configuration of network system SYS according to the second modification of the embodiment of the present invention is the same as that in FIG. 1, and the hardware configuration and control structure of information processing apparatus PC are the same as those in FIGS. 2 and 3, respectively. Therefore, detailed description will not be repeated.

  In the second modification, as in the above-described embodiment, when Node 1 rejoins the network system SYS, Node 1 acquires the pre-update list 136 and the latest list 138 (similar to FIG. 7).

  After the state shown in FIG. 7 is reached, Node 1 transmits a ping command to all the Nodes constituting the network system SYS. At this time, a command for returning a response of a predetermined data amount is added to the ping command. And Node1 measures the response time until it receives a response from each Node after transmission of a ping command, respectively. Furthermore, Node1 calculates the data transmission rate (typically Bit / sec) between Node1 and each Node in the network system SYS. That is, when the response data amount is B [Bit] and the corresponding response time is t [sec], the Node 1 sets the respective data transmission rates according to the relational expression of data transmission rate = B / t, respectively. calculate.

  Next, Node 1 divides the total size of the shared data to be acquired (see FIG. 8) by the data transmission rate, and calculates the expected time required to acquire all the shared data to be acquired between Node 1 and each Node. Calculate each. Then, Node 1 compares the expected time for each Node with a predetermined target acquisition completion time, and if the expected time for any Node is less than the target acquisition completion time, the synchronization mode is determined as “single mode”. To do. Then, the node with the shortest expected time is designated as the shared data transmission request destination.

  On the other hand, if the expected time for any Node is equal to or longer than the target acquisition completion time, Node 1 determines the synchronization mode as “multiple modes”. Then, Node 1 determines the transmission request destinations of the acquisition target data in a distributed manner so that the time required for acquisition of all shared data falls within the target acquisition completion time.

  Since other processes are the same as those in the above-described embodiment, detailed description will not be repeated.

  According to the second modification of the embodiment of the present invention, the synchronization mode and the transmission request destination can be determined more reflecting the state of the network system SYS.

[Third Modification of Embodiment]
There is a high possibility that the number of shared data added or changed during a period in which the rejoined Node is offline is substantially proportional to the offline period. Therefore, when any node rejoins the network system, the synchronization mode may be determined based on the length of the offline period immediately before the rejoining.

  That is, the longer the offline period, the higher the possibility that the number of shared files to be acquired will increase. In such a case, it is preferable to select “multiple modes” as the synchronization mode.

  Therefore, each Node starts time measurement after leaving the network system, and if the time at the time of rejoining the network system (the length of the offline period) is less than the predetermined threshold time, the synchronization mode is set. Decide on “Single mode”. In other cases, the synchronization mode is determined as “multiple mode”.

  Since other processes are the same as those in the above-described embodiment, detailed description will not be repeated.

  According to the third modification of the embodiment of the present invention, the synchronization mode can be quickly determined when the Node rejoins the network system.

[Fourth Modification of Embodiment]
In the above-described embodiment, the configuration in which the synchronization mode is determined based on the number of pieces of shared data to be acquired has been illustrated, but it may be comprehensively determined from a plurality of items.

  Specifically, each item of data information of the data to be acquired is weighted and then the sum is calculated. If the sum is less than a predetermined threshold, the synchronization mode is set to “single mode”. In other cases, the synchronization mode is determined as “multiple modes”.

  Specific examples of such weighting calculations include the importance of each shared data, the number of user accesses to each shared data (the value increases as the number of accesses increases), the update date / time of each shared data (the value increases as the update date is newer) Large).

  According to the fourth modified example of the embodiment of the present invention, the synchronization mode can be determined in consideration of the shared data to be acquired.

[Fifth Modification of Embodiment]
In the above-described embodiment, the configuration in which the synchronization process is executed according to the synchronization mode once the synchronization mode is determined once the offline Node rejoins the network system has been illustrated. However, after the “single mode” is selected, when the network environment or the Node environment changes and the load on the node to which the shared data is requested is increased, the synchronization process is distributed to other Nodes. It is preferable.

  Specifically, when the Node that is the transmission destination of shared data determines that the shared data cannot be properly transmitted, a part of the request content is transferred to another Node, and the Node of the transfer destination is the content of the request. To continue sending shared data. It should be noted that the request contents to be transferred include the specific information of the shared data and the transmission destination of the shared data.

  Alternatively, the Node that requested the transmission of the shared data monitors the time required for transmitting the shared data from the request destination, and if the time required for the transmission exceeds a predetermined threshold, the node sends a data transmission request. Retransmit to another Node. Note that the Node to which the data transmission request is retransmitted can be determined based on a response to the ping command or the like.

  According to the fifth modification of the embodiment of the present invention, the synchronization mode can be appropriately determined according to the change in the status of the network system.

[Other embodiments]
The program according to the present invention may be a program module that is provided as part of an operating system (OS) of a computer and that calls necessary modules in a predetermined arrangement at a predetermined timing to execute processing. . In that case, the program itself does not include the module, and the process is executed in cooperation with the OS. A program that does not include such a module can also be included in the program according to the present invention.

  The program according to the present invention may be provided by being incorporated in a part of another program. Even in this case, the program itself does not include the module included in the other program, and the process is executed in cooperation with the other program. Such a program incorporated in another program can also be included in the program according to the present invention.

  The provided program product is installed in a program storage unit such as a hard disk and executed. Note that the program product includes the program itself and a storage medium in which the program is stored.

  Furthermore, part or all of the functions realized by the program according to the present invention may be configured by dedicated hardware.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic configuration diagram of a network system according to an embodiment of the present invention. It is a schematic diagram showing a schematic hardware configuration of a personal computer that is a representative example of the information processing apparatus according to the embodiment of the present invention. It is the schematic which shows the control structure in the information processing apparatus according to embodiment of this invention. It is a figure which shows the state of the network system just before Node1 leaves | separates. It is a figure which shows the state of the network system immediately after Node1 rejoins. It is a figure which shows the process performed immediately after Node1 rejoins. It is a figure which shows the state of the network system after execution of the process shown in FIG. It is a figure which shows an example of the list | wrist which Node1 hold | maintains. It is a figure for demonstrating the process for determining the acquisition destination of the shared data in single mode. It is a figure for demonstrating the process in the shared data acquisition in single mode. It is a figure which shows the state which the acquisition process of the shared data in single mode completed. It is a figure which shows another example of the list | wrist hold | maintained by Node. It is a figure which shows the state after rearrangement of the newest list shown in FIG.12 (b). It is a figure for demonstrating the process which performs the transmission request to each Node in multiple modes. It is a figure for demonstrating the process which acquires shared data from each Node in multiple modes. It is a sequence diagram concerning the synchronization processing according to the embodiment of the present invention. It is a sequence diagram concerning the shared data addition processing according to the embodiment of the present invention.

Explanation of symbols

  102 data reception unit, 104 data analysis unit, 106 data operation unit, 108 list management unit, 110 authentication unit, 112 network application unit, 114 connection table management unit, 116 shared data holding unit, 118 mode determination unit, 120 data storage unit 122 data creation unit, 124 data transmission unit, 132 connection table, 134 list, 136 list before update, 138 latest list, 200 CPU, 202 internal bus, 204 display unit, 206 network interface (I / F) unit, 208 input Section, 210 hard disk section, 212 memory section, 214 CD-ROM drive, 216 flexible disk drive, NW network, PC, PC1 to PC7 information processing apparatus, RT1, RT2, RT3 router, SYS Network system.

Claims (15)

A shared data synchronization method for synchronizing and holding shared data between a plurality of information processing devices capable of data communication with each other,
An information processing device that is to synchronize the shared data, and determining a situation when the information is synchronized;
A first mode in which the information processing apparatus to synchronize the shared data acquires the acquisition target shared data only from one other information processing apparatus according to the determined situation, and the acquisition target shared data. Selecting one of the second modes acquired in a distributed manner from a plurality of other information processing devices, and determining an information processing device as an acquisition destination;
A method of synchronizing shared data, comprising: an information processing device that is to synchronize the shared data, acquiring the acquired shared data from an information processing device that has been determined as an acquisition destination. The information processing apparatus holds a list for managing the shared data in addition to the shared data,
The method for synchronizing the shared data further includes a step in which an information processing device to synchronize the shared data acquires the list from another information processing device,
The shared data synchronization method according to claim 1, wherein in the step of determining the situation, the situation is determined based on the contents of the acquired list.   In the step of determining the situation, the shared data to be acquired is determined based on a difference between the list held by the information processing apparatus to which the shared data is to be synchronized and a list acquired from another information processing apparatus. The method for synchronizing shared data according to claim 2.   4. The shared data synchronization method according to claim 3, wherein the selection between the first mode and the second mode is performed based on a size of the shared data to be acquired.   5. The shared data synchronization method according to claim 1, wherein, in the step of determining the situation, the situation is determined based on a response time from another information processing apparatus.   The shared data synchronization according to claim 1, wherein in the step of determining the situation, the situation is determined based on a data transmission rate of a response from another information processing apparatus. Method. The plurality of information processing devices constitutes a network,
The step of determining the situation determines the situation based on a length of a period during which an information processing apparatus that should synchronize the shared data has left the network. The shared data synchronization method described in 1.   In the step of determining the information processing apparatus as the acquisition destination, when the first mode is selected, the candidate information processing apparatus with the fastest response is determined as the information processing apparatus as the acquisition destination. The method for synchronizing shared data according to claim 1.   In the step of determining the information processing apparatus of the acquisition destination, the information processing apparatus of the acquisition destination is determined with information processing apparatuses close to the information processing apparatus that should synchronize the shared data on a communication path as candidates. Item 9. The shared data synchronization method according to any one of Items 1 to 8.   In the step of determining the information processing apparatus as the acquisition destination, when the second mode is selected, a candidate group consisting of information processing apparatuses close to the information processing apparatus that is to synchronize the shared data on the communication path; In addition to distinguishing it from a candidate group consisting of other information processing devices, the acquisition source of each shared data selects an information processing device from one of the candidate groups according to the data information of the shared data to be acquired The shared data synchronization method according to claim 1, wherein the shared data synchronization method is performed.   The information processing device close to the information processing device to synchronize the shared data includes an information processing device to which a broadcast message from the information processing device to synchronize the shared data can be reached. How to synchronize shared data. Each of the information processing devices has a network address composed of a network number and a host number,
The information processing apparatus close to the information processing apparatus to synchronize the shared data includes an information processing apparatus having the same network number as the network number of the information processing apparatus to synchronize the shared data. 2. The shared data synchronization method according to claim 1.   The information processing apparatus to which the shared data is to be synchronized further includes a step of storing the acquired shared data in its own storage unit and updating the contents of the list. How to sync your shared data. A program for synchronizing shared data between a plurality of information processing devices connected to each other so that data communication is possible,
The program is stored in the information processing apparatus.
Determining the situation at the time when the shared data is to be synchronized;
According to the determined situation, a first mode in which the acquisition target shared data is acquired from only one other information processing apparatus, and the acquisition target shared data is acquired in a distributed manner from a plurality of other information processing apparatuses. Selecting any one of the second modes to be performed, and determining an information processing apparatus as an acquisition destination;
A program for synchronizing shared data, causing the information processing apparatus determined as an acquisition destination to execute the step of acquiring the acquisition-target shared data. A network system capable of holding shared data synchronously among a plurality of information processing devices capable of data communication with each other,
An information processing apparatus that synchronizes the shared data is:
Means for determining a situation when synchronizing the shared data;
According to the determined situation, a first mode in which the acquisition target shared data is acquired from only one other information processing apparatus, and the acquisition target shared data is acquired in a distributed manner from a plurality of other information processing apparatuses. Selecting a second mode to determine, and determining an information processing apparatus as an acquisition destination;
A network system capable of holding shared data synchronously, including means for acquiring the shared data to be acquired from an information processing apparatus determined as an acquisition destination.

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