Patent Publication Number: US-6337864-B1

Title: Information transmission apparatus, information transmission method, and medium recorded with information transmission program, in store-and-forward type of electronic conference system

Description:
FIELD OF THE INVENTION 
     The present invention relates to a store-and-forward type of electronic conference system, and particularly to a technique for improving the reliability of the electronic conference system, by minimizing the quantity of informations to be transmitted, or by assuring the sequence of informations to be transmitted. 
     RELATED ART OF THE INVENTION 
     Generally, an “electronic conference system” designates or specifies those systems constituted for information-exchange between unspecified number of users. In a large-scale electronic conference system, the users of the electronic conference system are registered at each of geographically separated areas (hereinafter called “site”). The registered user can use only the site at which he has been registered. 
     In such an electronic conference system, there is generally adopted a store-and-forward type of communication system, such as in view of transmission speed of communication lines connecting between the sites. That is, the information generated at each of the sites is once stored into a transmission queue which stores informations to be transmitted, and then collectively or batch transmitted at each of a predetermined time of period. The information received at each sites other than the transmitting sites is once stored into a reception queue for storing received informations, and then processed by that background which has processing ability to spare. 
     Typically, electronic conference systems utilize those unit containers named “forum”. Further, the forums include hierarchical messages as informations. 
     However, in such an electronic conference system, there is adopted the store-and-forward type of communication system, so that there may occur such disadvantage, upon transmission of informations which have been stored in the transmission queue, as follows. 
     (1) In case that the informations are stored in the transmission queue in a sequence or order of “message creation, message modification, and message deletion” for a certain message, no effects will occur at the site which will receive these informations. Namely, when this series of informations comprising “message creation, message modification, and message deletion” are processed in this order or sequence, the message at issue will be resultantly deleted. This means that no processings have been executed for the message. As described above, the informations to be transmitted may include meaningless or wasteful informations, so that the communication efficiency may be deteriorated due to such wasteful increase of information quantity. 
     (2) When the transmission queue is stored such as with informations in a sequence of “creation of forum” and “writing (i.e., creation) of a message into the forum”, these informations should be transmitted in the order of “creation of forum” and “creation (or writing) of message”. However, upon transmission of the information designating “creation of forum”, there may occur a communication error such as due to trouble of a communication circuit. In this case, if the information designating “creation of message” is normally transmitted, there occurs such a trouble that the message is to be written into or created in a “not created forum”. 
     SUMMARY OF THE INVENTION 
     In view of the aforementioned problems in the conventional technique, it is therefore a purpose of the present invention to dissolve the aforementioned defects to thereby improve the reliability of the electronic conference system, by optimizing the informations or assuring the sequence of the informations, stored in the transmission queue which realizes the store-and-forward type of communication system. 
     It is another purpose of the present invention to distribute those mediums which are recorded with the information transmission program according to the present invention, to thereby promote those persons, who have obtained such mediums, to easily constitute an information transmission apparatus. 
     A first solution for achieving the above purposes is constituted by: an information transmission apparatus in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored in a queue and the stored operational informations are batch transmitted between information administrating devices which administrate the various objects, the apparatus comprising an information deletion device for deleting the series of informations in the operational informations stored in the queue, which do not cause any resultant changes. 
     According to such a constitution, there are deleted, from those operational informations stored in the queue, the series of informations which do not cause any resultant changes. Namely, there is reduced the quantity of informations to be transmitted between information administrating devices, so that the optimization of informations is performed. Thus, the communication efficiency is improved by virtue of decrease of the quantity of informations, so that the reliability of the electronic conference system can be improved. 
     Concretely, the information deletion device may be constituted to delete, when a deletion operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the deletion operational information. 
     According to such a constitution, when a deletion operational information of a certain object exists in the queue, it can be judged that no resultant changes will be caused by update processings performed before the object deletion. Thus, by deleting the update operational informations for the certain object from the queue, there can be further reduced the quantity of informations to be transmitted between the information administrating devices. 
     Further, the information deletion device may be constituted to delete, when a creation operational information for the certain object which is an operation target of the deletion operational information is stored in the queue, the creation operational information and the deletion operational information. 
     According to such a constitution, when a creation operational information for the certain object exists in the queue, it can be judged that the certain object has not been created yet in other information administrating devices. Thus, by deleting the creation operational information and the deletion operational information from the queue, there can be further reduced the quantity of informations to be transmitted between the information administration devices. 
     Further, the information deletion device may be constituted to delete, when an update operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the update operational information. 
     According to such a constitution, even when the update of the certain object is performed for several times, it is possible for other information administrating devices to update the certain object to the latest contents by virtue of the latest update operational information only. Namely, it can be said that the truly necessary update operational information for the certain object is the latest one. As such, by deleting those update operational informations for the certain object which informations have been stored before the latest update operational information for the certain object, there can be further reduced the quantity of informations to be transmitted between the information administrating devices. 
     A second solution for achieving the above purposes is constituted by: an information transmission apparatus in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored into a queue and the stored operational informations are batch transmitted between information administrating devices which administrate the various objects, the apparatus comprising a transmission state registration device for registering the transmission state of the operational information, an error detection device for detecting as to whether a transmission error has occurred or not, a registration controlling device for registering into the transmission state registration device, when an occurrence of transmission error is detected by the error detection device, the information administrating means which is the destined information administrating device and for which the transmission error has occurred, a skipping device for retrieving the transmission state registration device, and for skipping the transmission of the operational information to the information administrating device which is registered in the transmission state registration device. 
     According to such a constitution, upon occurrence of a transmission error, there is registered into the transmission state registration device the information administrating device which is the destined information administrating device and for which the transmission error has occurred. Further, by the skipping device, there is skipped the transmission of operational informations toward the information administrating device which is registered in the transmission state registration device. Namely, those operational informations after occurrence of a transmission error are not transmitted to the information administrating device for which the transmission error has occurred, so that the sequence assurance of informations can be realized. Thus, even when the operational informations of objects have not been correctly transmitted, the sequence of the informations can be guaranteed, so that the reliability of the electronic conference system can be improved. Further, the communication efficiency can be also improved, since there is avoided the transmission to the information administrating device for which the transmission error has occurred. 
     The apparatus may further comprise an initializing device for initializing the transmission state registration device, upon transmission of the operational informations. 
     According to such a constitution, the transmission state registration device is initialized before transmission of operational informations. Namely, the operational informations are not transmitted to the information administrating device for which the transmission error has occurred, only within the period of time during which the series of operational informations stored in the queue are transmitted. Accordingly, such as in case that the cause of transmission error has been dissolved during the period of time between the last transmission and the transmission at this time, it is again tried to transmit the operational informations toward the information administrating device toward which the last transmission was not performed. Thus, toward the information administrating device for which the transmission error has occurred, the operational informations are transmitted after the cause of transmission error has been dissolved, so that the reliability of the electronic conference system can be further improved. 
     A third solution for achieving the above purposes is constituted by: an information transmission method in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored in a queue and the stored operational informations are batch transmitted between information administrating processes which administrate the various objects, the method comprising an information deletion process for deleting the series of informations in the operational informations stored in the queue, which do not cause any resultant changes. 
     According to such a constitution, there are deleted, from those operational informations stored in the queue, the series of informations which do not cause any resultant changes. Namely, there is reduced the quantity of informations to be transmitted between information administrating processes, so that the optimization of informations is performed. Thus, the communication efficiency is improved by virtue of decrease of the quantity of informations, so that the reliability of the electronic conference system can be improved. 
     Concretely, the information deletion process may be constituted to delete, when a deletion operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the deletion operational information. 
     According to such a constitution, when a deletion operational information of a certain object exists in the queue, it can be judged that no resultant changes will be caused by update processings performed before the object deletion. Thus, by deleting the update operational informations for the certain object from the queue, there can be reduced the quantity of informations to be transmitted between the information administrating processes. 
     Further, the information deletion process may be constituted to delete, when an update operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the update operational information. 
     According to such a constitution, even when the update of the certain object is performed for several times, it is possible for other information administrating processes to update the certain object to the latest contents by virtue of the latest update operational information only. Namely, it can be said that the truly necessary update operational information for the certain object is the latest one. As such, by deleting those update operational informations for the certain object which informations have been stored before the latest update operational information for the certain object, there can be further reduced the quantity of informations to be transmitted between the information administrating process. 
     A fourth solution for achieving the above purposes is constituted by an information transmission method in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored in a queue and the stored operational informations are batch transmitted between information administrating processes which administrate the various objects, the method comprising a transmission state registration process for registering the transmission state of the operational information, an error detection process for detecting as to whether a transmission error has occurred or not, a registration controlling process for registering into the transmission state registration process, when an occurrence of transmission error is detected by the error detection process, the information administrating process which is the destined information administrating process and for which the transmission error has occurred, a skipping process for retrieving the transmission state registration process, and for skipping the transmission of the operational information to the information administrating process which is registered in the transmission state registration process. 
     According to such a constitution, upon occurrence of a transmission error, there is registered into the transmission state registration process the information administrating process which is the destined information administrating process and for which the transmission error has occurred. Further, by the skipping process, there is skipped the transmission of operational informations toward the information administrating process which is registered in the transmission state registration process. Namely, those operational informations after occurrence of a transmission error are not transmitted to the information administrating process for which the transmission error has occurred, so that the sequence assurance of informations can be realized. Thus, even when the operational informations of objects have not been correctly transmitted, the sequence of the informations can be guaranteed, so that the reliability of the electronic conference system can be improved. Further, the communication efficiency can be also improved, since there is avoided the transmission to the information administrating process for which the transmission error has occurred. 
     A fifth solution for achieving the above purposes is constituted by: a medium recorded with an information transmission program in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored into a queue and the stored operational informations are batch transmitted between information administrating functions which administrate the various objects, wherein the medium is recorded with a program for realizing an information deletion function for deleting that series of informations in the operational informations stored in the queue, which do not cause any resultant changes. 
     In this respect, the term “medium” is readable such as onto paper card (punch card), paper tape, magnetic tape, magnetic disk, magnetic drum, CD-ROM, IC card, which can assuredly record various informations which can be assuredly read out if required. 
     According to such a constitution, the medium is recorded with the program for realizing the information deletion function for deleting the series of informations in the operational informations stored in the queue, which do not cause any resultant changes. As such, the information transmission program according to the present invention can be distributed, and those, who have obtained such a medium, can easily constitute an information transmission apparatus, making use of a general electronic computer. 
     Concretely, the information deletion function may be constituted to delete, when a deletion operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the deletion operational information. 
     According to such a constitution, when a deletion operational information of a certain object exists in the queue, it can be judged that no resultant changes will be caused by update processings performed before the object deletion. Thus, by deleting the update operational informations for the certain object from the queue, there can be further reduced the quantity of informations to be transmitted between the information administrating functions. 
     Further, the information deletion function may be constituted to delete, when an update operational information for a certain object is stored in the queue, those update operational informations for the certain object which update operational informations have been stored before the update operational information. 
     According to such a constitution, even when the update of the certain object is performed for several times, it is possible for other information administrating functions to update the certain object to the latest contents by virtue of the latest update operational information only. Namely, it can be said that the truly necessary update operational information for the certain object is the latest one. As such, by deleting those update operational informations for the certain object which informations have been stored before the latest update operational information for the certain object, there can be further reduced the quantity of informations to be transmitted between the information administrating functions. 
     A sixth solution for achieving the above purposes is constituted by a medium recorded with an information transmission program in a store-and-forward type of electronic conference system in which operational informations representing operations performed for various objects are stored in a queue and the stored operational informations are batch transmitted between information administrating functions which administrate the various objects, wherein the medium is recorded with a program for realizing a transmission state registration function for registering the transmission state of the operational information, an error detection function for detecting as to whether a transmission error has occurred or not, a registration controlling function for registering into the transmission state registration function, when an occurrence of transmission error is detected by the error detection function, the information administrating function which is the destined information administrating function and for which the transmission error has occurred, a skipping function for retrieving the transmission state registration function, and for skipping the transmission of the operational information to the information administrating function which is registered in the transmission state registration function. 
     According to such a constitution, the medium is recorded with the program for realizing the transmission state registration function, the error detection function, the registration controlling function, and the skipping function. As such, the information transmission program according to the present invention can be distributed, and those, who have obtained such a medium, can easily constitute the information transmission apparatus, making use of a general electronic computer. 
    
    
     Further purposes, advantages and details of the present invention will become more apparent from the following description of the preferred embodiments when read in conjunction with the accompanying drawings. 
     BRIEF EXPLANATION OF THE DRAWINGS 
     FIG. 1 is a schematic view showing an electronic conference system according to one embodiment of the present invention; 
     FIG. 2 is an explanatory diagram showing a hierarchy structure of the forums in the system; 
     FIG. 3 is an explanatory diagram showing a hierarchy structure of the messages in the system; 
     FIG. 4 is an explanatory diagram of the objects registered in a database in the system; 
     FIG. 5 is an explanatory diagram of an object ID for specifying the object in the system; 
     FIG. 6 is an explanatory diagram of destination-informations for specifying the information-exchange-destination, in the system; 
     FIG. 7 is a process flow diagram showing a flow of information-exchange in the system; 
     FIG. 8 is a flow chart describing a process for editing objects; 
     FIG. 9 is a flow chart describing a process for creating objects; 
     FIG. 10 is a flow chart describing a process for deleting objects; 
     FIG. 11 is a flow chart describing a process for updating objects; 
     FIG. 12 is a flow chart describing a process for moving objects; 
     FIG. 13 is an explanatory diagram showing a necessity of the process for moving objects; 
     FIG. 14 is a flow chart showing a process for optimizing the information; 
     FIG. 15 is a flow chart showing a deletion process of a message on a queue; 
     FIG. 16 is a flow chart showing a update process of a message on a queue; 
     FIG. 17 is a flow chart showing a deletion process of a forum on a queue; 
     FIG. 18 is a flow chart showing a update process of a forum on a queue; 
     FIG. 19 is a flow chart showing a process for assuring information sequence; 
     FIG. 20 is a flow chart showing a process of a received information; 
     FIG. 21 is a flow chart showing a process for checking a destination inconsistency; 
     FIG. 22 is a flow chart showing a process for checking an inconsistency of information contents; 
     FIG. 23 is a flow chart showing a process for registration into the database; 
     FIG. 24 is a flow chart showing a process for updating a recovery information; 
     FIG. 25 is a flow chart also showing a process for updating a recovery information; and 
     FIG. 26 is a flow chart showing a recovery process. 
    
    
     PREFERRED EMBODIMENTS 
     The present invention will be described in detail hereinafter, with reference to the accompanying drawings. 
     FIG. 1 shows a system architecture in which an electronic conference system according to one embodiment of the present invention is constituted between four sites A, B, C, and D which are geographically separated from one another. Namely, the electronic conference system is attained by a client/server model in which the sites A, B, C and D are connected to one another via communication line. Each of the servers and clients is constituted of an electronic computer which is provided with at least a central processing unit (CPU) and a suitable memory, and executes a program on the memory. 
     Each of the sites is constituted to include one server  10  (information administrating device, information administrating process, information administrating function), and at least one client  30 . The sites are mutually connected via communication lines  40 . The information-exchange between the sites are conducted by means of a store-and-forward type of communication system, such as in view of a transmission speed of the communication line  40 . Namely, the information occurred at the client  30  of site A is not transmitted upon its occurrence towards sites B, C and D, but stored once for a while in site A and then batch transmitted at each of a predetermined time of period. 
     Each of the servers  10  is constituted to include a database  12  (information storing device, information storing process, information storing function), a server software  14 , a command queue  16 , a transmission queue  18 , and a reception queue  20 . Each server software  14  is adapted for referring to and updating its accompanying database  12 . Each command queue  16  stores the operational contents of information occurred within the accompanying site, each transmission queue  18  stores information to be transmitted to other sites, and each reception queue  20  stores information received from other sites. These command queue  16 , transmission queue  18  and reception queue  20  are constituted of files which form FIFO (First In First Out) type of queues or waiting lines, respectively. 
     By means of programs, each server software  14  provides information deletion device, transmission state registration device, error detection device, registration controlling device, skipping device, initializing device, information deletion process, transmission state registration process, error detection process, registration controlling process, skipping process, information deletion function, transmission state registration function, error detection function, registration controlling function and skipping function. 
     Prepared in each database  12  are forums serving as units (containers) for conducting information-exchange. As shown in FIG. 2, forums can be constituted in a hierarchy structure, in which the forum A at the highest level is called “main forum” while each of remaining forums B 1 , B 2 , C is called “sub-forum”. The sub-forums can be created in a plural manner at the same level. For example, the forum B 1  and forum B 2  have been created at the same level. 
     As shown in FIG. 3, each of the forums includes messages in a hierarchy structure. The message A at the highest level is called “topic”, and has its subject (heading, or title) such as “About . . . ”. Each of other messages B, C 1 , C 2  and D are called “reply” which defines a response or answer to a certain message. In this concern, it is possible to assign a plurality of replies to a certain message. In FIG. 3, the replies for the message B are the messages C 1  and C 2 . 
     Stored in the site, at which the forums are created, are original ones of the forums (original), while the duplications (replica) of the forums are stored in other sites. The users of the forums in the electronic conference system are to perform a working job such as creation of messages for the forum (no matter whether this forum is an original or a replica), to which forum the users belong. The working jobs performed for the forums are transmitted to other sites via communication line  40  by means of the store-and-forward type of communication system, so as to be reflected to the forums of the other sites. As such, there occur time-wise lags between the contents of each sites. 
     For detailed explanation of the contents of database  12 , FIG. 4 shows that the database  12  includes a forum object  50 , a message object  52 , a user object  54  and a site object  56 . Each of these objects is assigned with an object ID (identification number) which is unique in the whole of the electronic conference system. Namely, the object ID is determined by a combination of a unique server ID, which is uniquely established in the whole of the electronic conference system, and a unique object ID, which is uniquely assigned to each object in each site. As shown in FIG. 5, such as in case of representing the object ID in a 32-bit manner, there is established a unique ID in the whole of the electronic conference system, by providing upper 16 bits with a server ID, and lower 16 bits with an ID which is uniquely assigned to each objects in each site. 
     The forum object  50 , which defines a forum, contains a name of forum, a name of a person who created this forum, a creation date and an explaining text, as well as a structural information for defining the hierarchy structure of the forum. The structural information includes an object ID and another object ID, representing a one-level higher forum object and the highest-level of forum (main forum) object, respectively. 
     The message object  52 , which defines a message, contains a subject (heading such as “About . . . ”), a name of a person who created this message, a creation date and a message text (contents of message), as well as a structural information for defining the hierarchy structure of the message. The structural information includes: an object ID of one-level higher message object which this message  52  is to reply to; another object ID of a topic object which this message  52  belongs to; and a further object ID of a forum object which this message  52  belongs to. 
     The user object  54 , which defines users of the electronic conference system, contains: client names of the clients  30  which are allowed to use the data base  12 ; and information such as a password for each of the clients  30  to log on. Thus, when a request for referring to the database  12  is issued from the client  30 , it can be judged as to whether this client  30  is such as authorized to refer to the database  12  or not, by checking the contents of the user object  54 . 
     The site object  56 , which defines a site, contains: client ID&#39;s designating those clients  30  which can use the database  12 ; and object ID&#39;s designating other available sites. 
     Further, each of the forums is registered with a destination-information which defines as to which site the information-exchange is to be conducted with. For example, in case that an information-exchange is to be conducted between the forum A of the site A and the forum A of the site B as shown in FIG. 6, the forum A of site A and the forum A of site B are registered with the site B as the destination-information  58  and the site A as the destination-information  58 , respectively. Thus, an information occurred at the site A is transmitted, in the example noted just above, to the site B, by referring to the registered destination-information  58  to thereby judge as to which site the information is to be transmitted to. 
     There will be explained hereinafter the operation of the electronic conference system having such a constitution as described above. 
     There is firstly explained an outline of information-exchange to be conducted between the sites, with reference to a process flow diagram of FIG.  7 . For expediency of explanation, the information-exchange is supposed to be conducted between the site A and site B, in the electronic conference system shown in FIG.  7 . 
     When the user of the electronic conference system creates, deletes, updates or moves a forum or a message (hereinafter called “object”) at the client  30  of the site A, its server software  14  functions to perform a registration processing to its accompanying database  12 , correspondingly to the user&#39;s working job to the object (processing ( 1 )). At the same time, the server software  14  retrieves from its accompanying database  12  such as an object ID of the object to be worked (processing ( 2 )), creates a command object to be noted later, and registers this command object to the accompanying command queue  16  (processing ( 3 )). 
     The command object is constituted to contain: a type of operation (such as creation of object); an object ID representing the information transmitter site; an object ID designating a transmittee site as a destination to which the information is to be transmitted; an object ID representing an object to be operated; and an information unique to each operation type. Such as in case of move of objects, the “information unique to each operation” does mean an information representing a move origination and a move destination, while in case of creation of objects, it does mean an information representing a creation position. 
     The command object registered in the command queue  16  is taken out from this queue  16 , by the background which has processing ability to spare in the accompanying server  10  (processing ( 4 )). Then, the body (text sentence, such as in case of message) of object to be processed is retrieved from the accompanying database  12  (processing ( 5 )), if necessary, and thereafter the command object and object body (hereinafter called communicative information) are registered into the transmission queue  18  (processing ( 6 )). 
     At this time, a “processing for optimizing information” is executed. Namely, this “processing for optimizing information” is a processing to minimize the quantity of information transmission between the sites, by eliminating those command objects registered in the command queue  16  which objects do not have any effects eventually. 
     The communicative informations registered in the transmission queue  18  are taken out from the queue  18  at each of a predetermined time of period. Then, the site B is determined as a transmittee or destined site based on the command object included in the taken out communicative information, and this communicative information is transmitted to the site B via the communication line  40  (processing ( 7 )). In this concern, the predetermined time of period may be arbitrarily determined by the administrator of the electronic conference system, such that the communicative informations are transmitted during at midnight or early in the morning where the communication line  40  usually has a sufficient time to spare. 
     At this time, a “processing for assuring sequence” is executed. Namely, this “processing for assuring information sequence” is a processing for avoiding occurrence of such an inconsistency in the sequence of information transmission, that is caused due to the store-and-forward type of communication system. 
     Meanwhile, the communicative information transmitted from the site A toward the site B is not immediately processed at the site B, but once stored into the reception queue  20  in the site B. The communicative information stored in the reception queue  20  is taken out therefrom at the background of the accompanying server  10  (processing ( 8 )), and a registration processing to the accompanying database  12  is executed correspondingly to the communicative information (processing ( 9 )). 
     At this time, there are executed such as “judgment processing and correction processing of destination inconsistency”, “judgment processing and correction processing of inconsistency in information contents”, and “move processing of objects”. Namely, the “judgment processing and correction processing of destination inconsistency” are processings for automatically judging and correcting an occurrence of inconsistency in the destination-information  58  registered in the site which has received the communicative information, respectively. The “judgment processing and correction processing of inconsistency in information contents” are processings for automatically judging and correcting an occurrence of inconsistency in the contents of the information registered in the site which has received the communicative information. The “move processing of objects” is a processing for rendering the objects be correctly moved regardless of the sequence of information transmission in case of moving the objects between those forums which have different transmission paths. 
     Further, in case of occurrence of trouble such as system down due to a certain cause (for example, cut-off of power such as due to power failure) in the server  10  of each site, there is performed an update by a recovery disk for recovering the server  10  to the state just before the occurrence of trouble. The update of recovery disk itself is performed at each site: upon creation, deletion, update, or move of the objects in or to the database  12 ; or based on the instructions of the system administrator. In case of occurrence of trouble such as system down, the server  10  is recovered to the state just before the occurrence of the trouble, such as by the manual operation of the system administrator and based on the contents of the recovery disk. 
     The above explained information-exchange is carried out by those processings executed by each of the server software  14 . 
     Shown in FIGS. 8 through 12 are those processings which are executed at each sites, when processing of creation, deletion, update, or move of object is requested from the client  30  to the server  10 . 
     FIG. 8 shows a main routine. 
     At step  1  (abbreviated as “S 1 ” in the figure, and the same rule is applied to hereinafter), it is judged as to whether the client  30  has requested a processing of object creation, or not. If the processing of object creation has been requested (Yes), the flow branches to step  10  so as to call a sub-routine (see FIG. 9) for performing a creation processing of a due object. The flow branches to step  2 , if the processing of object creation has not been requested (No). 
     At step  2 , it is judged as to whether the client  30  has requested a processing of object deletion, or not. If the processing of object deletion is requested (Yes), the flow branches to step  20  so as to call a sub-routine (see FIG. 10) for performing a deletion processing of a due object. The flow branches to step  3 , if the processing of object deletion is not requested (No). 
     At step  3 , it is judged as to whether the client  30  has requested a processing of object update, or not. If the processing of object update is requested (Yes), the flow branches to step  30  so as to call a sub-routine (see FIG. 11) for performing an update processing of a due object. The flow branches to step  4 , if the processing of object update is not requested (No). 
     At step  4 , it is judged as to whether the client  30  has requested a processing of object move, or not. If the processing of object move is requested (Yes), the flow branches to step  40  so as to call a sub-routine (see FIG. 12) for performing a move processing of a due object. The flow branches to step  5 , if the processing of object move is not requested (No). 
     At step  5 , it is judged that the processing request is in error, since the processing request from the client  30  is not anyone of creation, deletion, update, and move of objects. Further, there is effected an error treatment such as for indicating to the operator of client  30  that whose operation is in error. 
     FIG. 9 shows a subroutine for performing the creation processing of the due object. 
     At step  11 , the due object is created in the database  12  at the site which the client  30  belongs to, which client  30  has requested the object creation processing. 
     At step  12 , it is judged as to whether the object creation is successfully performed or not. If the creation is successful, the flow branches to step  13  (Yes). If failed, the flow branches to step  14  (No). 
     At step  13 , there is created a command object which designates an object creation, and this command object is registered to the command queue  16 . 
     At step  14 , there is effected an error treatment such as for indicating to the operator of client  30  that the object creation has failed. 
     FIG. 10 shows a subroutine for performing the deletion processing of the due object. 
     At step  21 , the due object is deleted from the database  12  at the site which that client  30  belongs to, which client  30  has requested the object deletion processing. 
     At step  22 , it is judged as to whether the object deletion is successfully performed or not. If the deletion is successful, the flow branches to step  23  (Yes). If failed, the flow branches to step  24  (No). 
     At step  23 , there is created a command object which designates an object deletion, and this command object is registered to the command queue  16 . 
     At step  24 , there is effected an error treatment such as for indicating to the operator of client  30  that the object deletion has failed. 
     FIG. 11 shows a subroutine for performing the update processing of the due object. 
     At step  31 , the due object is updated in the database  12  at the site which the client  30  belongs to, which client  30  has requested the object update processing. 
     At step  32 , it is judged as to whether the object update is successfully performed or not. If the update is successful, the flow branches to step  33  (Yes). If failed, the flow branches to step  34  (No). 
     At step  33 , there is created a command object which designates an object update, and this command object is registered to the command queue  16 . 
     At step  34 , there is effected an error treatment such as for indicating to the operator of client  30  that the object update has failed. 
     FIG. 12 shows a subroutine for performing the move processing of the due object. 
     At step  41 , the due object in the database  12  is moved at the site which the client  30  belongs to, which client  30  has requested the object move processing. 
     At step  42 , it is judged as to whether the object move is successfully performed or not. If the move is successful, the flow branches to step  43  (Yes). If failed, the flow branches to step  46  (No). 
     At step  43 , it is judged as to whether the object move is to be exclusively performed within a single or sole main forum, or not. If the move is within a single main forum, the flow branches to step  44  (Yes). If not within a single main forum, the flow branches to step  45  (No). 
     At step  44 , there is created a command object which designates an object move, and this command object is registered to the command queue  16 . This command object, which designates the object move, is added with an information which represents a move origination and a move destination. 
     At step  45 , there are created command objects which designate an object creation and an object deletion, respectively, and these command objects are registered to the command queue  16 . Namely, the object move processing is substituted by an object creation processing and an object deletion processing, so as to avoid such disadvantage to be described later. In this concern, the command object, which designates the object creation, is added with an information designating a creation position of the object, i.e., move destination of the object. The command object, which designates the object deletion, is added with an information designating a deletion position of the object, i.e., move origination of the object. 
     At step  46 , there is effected an error treatment such as for indicating to the operator of client  30  that the object move has failed. 
     According to the above explained processings of FIGS. 8 through 12, when processing of creation, deletion, update, or move of object is requested from the client  30  to the server  10 , the contents of processing request is analyzed to thereby call the subroutine which corresponds to appropriate one of the respective processings. At each of the corresponding subroutines for executing respective processings, there is executed the object processing in a real time manner in the site at which the request of object processing has occurred, while a command object representing each processing contents is substantially concurrently registered into the command queue  16 . 
     The reason why the move processing is performed in such a manner shown in FIG. 12, is as follows: 
     As shown in FIG. 13, it is now supposed that a main forum A and a main forum B have been established in the site A, and a sub-forum C has been established at the lower level of the main forum B. In addition, an information transmission path for the main forum A of site A is supposed to be established, so that the information is linearly transmitted to sites B, C, D and E. Further, it is supposed that, for the main forum B of site A, an information transmission path is established to a site D via site B, and another information transmission path is established to a site E via site C. 
     It is now assumed that the sub-forum C is moved to a lower level of the main forum A. This move of sub-forum C to the lower level of the main forum A does mean a creation of a sub-forum C for the main forum A. Contrary, this is nothing other than deletion of sub-forum C for the main forum B. Then arises such a situation that the site D is transmitted with both informations, i.e., a creation of sub-forum C by an information via the information transmission path originated from the main forum A, and a deletion of sub-forum C by another information via the information transmission path originated from the main forum B. 
     However, the site D is not necessarily transmitted with these informations, in the order or sequence of “deletion and creation” of the sub-forum C. As such, if the site D is transmitted with these informations in the order of “creation and deletion” of the sub-forum C, the result is that the sub-forum C does not exist in the site D. Due to this reason, it is not always possible to regard a move of object between forums having different information transmission paths, as being a move of object. Thus, it is necessary to perform different processings depending on as to whether the move is to be performed within a single main forum or not. 
     Shown in FIGS. 14 through 18 are those processings which are executed at each site, when the command objects are taken out from the command queue  16  at the background of the server  10 , and registered to the transmission queue  18 . These processings shown in FIGS. 14 through 18 are the aforementioned information optimizing processing, and correspond to information deletion device, information deletion process and information deletion function. 
     FIG. 14 shows a main routine of the information optimization processing. 
     At step  50 , the command objects registered in the command queue  16  are readout to be spread on the memory. Namely, there is created a duplication of command queue  16  onto the memory. 
     At step  51 , a searching is started from the latest item (“item” means the “command object”, and the same rule is applied to hereinafter) in the command queue spread onto the memory (hereinafter called “command queue on the memory”). Namely, the latest item is considered in the first processing loop, and the remaining items are considered one after another in the processing loops after the second loop inclusive, in a retroacting manner, or in the older direction or sequence. 
     At step  52 , it is judged as to whether the currently considering item is a command object designating a message deletion, or not. Such a judgment (as well as the judgment on an update of message, a deletion or update of forum, to be explained later) is performed by checking the type of operation included in the command object. If it is a deletion of message, the flow branches to step  60  (Yes) to call a subroutine (FIG. 15) for performing a queue processing for message deletion. Contrary, if it is not a deletion of message, the flow branches to step  53  (No). 
     At step  53 , it is judged as to whether the currently considering item is a command object designating a message update, or not. If it is an update of message, the flow branches to step  80  (Yes) to call a subroutine (FIG. 16) for performing a queue processing for message update. Contrary, if it is not an update of message, the flow branches to step  54  (No). 
     At step  54 , it is judged as to whether the currently considering item is a command object designating a forum deletion, or not. If it is a deletion of forum, the flow branches to step  90  (Yes) to call a subroutine (FIG. 17) for performing a queue processing for forum deletion. Contrary, if it is not a deletion of forum, the flow branches to step  55  (No). 
     At step  55 , it is judged as to whether the currently considering item is a command object designating a forum update, or not. If it is an update of forum, the flow branches to step  110  (Yes) to call a subroutine (FIG. 18) for performing a queue processing for forum update. Contrary, if it is not an update of forum, the flow branches to step  56  (No). 
     At step  56 , it is judged as to whether all items included in the command queue on the memory have been treated, or not. If all items have been treated, this routine is terminated (Yes). If all items have not been treated, the flow goes back to step  50  (No). 
     FIG. 15 shows a subroutine for performing a command object processing according to message deletion to be executed in the processing for optimizing information. 
     At step  61 , there is executed an initialization for setting a flag to “0”. This flag indicates as to whether the command queue on the memory is registered with a command object designating a message creation, or not. 
     At step  62 , from the item next to the item which relates to the message to be deleted, there is searched for an item having an object ID identical with that of the message to be deleted. Namely, the item next to the item related to the deletee message (i.e., message to be deleted) is considered in the first processing loop, and the remaining items are considered one after another in the processing loops after the second loop inclusive, in a retroacting manner. 
     At step  63 , it is judged as to whether the currently considering item is a command object designating a creation of the message, or not. If it is such a message creation, the flow branches to step  64  (Yes) to set the flag to “1”. If it is not such a message creation, the flow branches to step  65  (No). 
     At step  65 , it is judged as to whether the currently considering item is a command object designating an update of the same message, or not. If it is such a message update, the flow branches to step  66  (Yes) to eliminate, from the command queue  16  on the files, a command object designating the message update. If it is not such a message update, the flow branches to step  67  (No). 
     At step  67 , it is judged as to whether the deletee message is a topic or not. Such a judgment can be effected by checking as to whether, the object ID designating an operatee target which is included in the command object, is identical with the object ID designating a topic object, which is included in the message object. The flow branches to step  68  (Yes) if the deletee target is a topic, or to step  71  if the deletee target is not a topic (No). 
     At step  68 , there are searched for command objects relating to a message (i.e., “reply”) at the lower level of the deletee “topic”, in the command queue on the memory. 
     At step  69 , it is judged as to whether a command object relating to a message at the lower level of topic has been found or not. If the command object relating to such a message is found, the flow branches to step  70  (Yes) to eliminate this command object relating to such a message, from the command queue  16  on the files. If a command object relating to such a message is not found, the flow branches to step  71  (No). 
     At step  71 , it is judged as to whether a treatment up to the final item, i.e., the oldest item in the command queue on the memory, has been completed or not. The flow branches to step  72  (Yes) if the final item has been treated, but branchingly goes back to the step  62  if the final item has not been treated (No). 
     At step  72 , it is judged as to whether the flag is “1” or not, i.e., whether a command object designating a creation of the message existed in the command queue on the memory or not. If the flag is “1”, the flow branches to step  73  (Yes), to eliminate the command objects designating message creation and deletion, respectively, from the command queue  16  on the files. If the flag is “0” (No), this routine is terminated. 
     According to those processings at steps  61  through  73  as explained above, if the command queue  16  on the files includes a command object designating a message deletion, it can be decided that no affects are eventually made by an update processing for the message to be executed before deletion of the message. Thus, by eliminating, from the command queue  16  on the files, those command objects designating such message update, the information quantity to be transmitted toward other sites is reduced. Contrary, if any command objects designating message creation are not found in the command queue  16 , it can be decided that a creation of the message at issue has been already performed. In this case, it is not performed to eliminate from the command queue  16  a command object designating a message deletion, to thereby avoid disadvantage. Further, in case that the deletee message is a topic, there are eliminated all of the command objects related to those messages (replies) at the lower levels of the topic, so that the information quantity to be transmitted toward other sites is further reduced. 
     FIG. 16 shows a subroutine for performing a queue processing according to message update to be executed in the processing for optimizing information. 
     At step  81 , in the command queue on the memory, from the item next to the item which relates to the message to be updated, there are searched for those items, each of which has an object ID identical with that of the message to be updated, and which designates a message update. Namely, the item next to the item related to the updatee message is considered in the first processing loop, and the remaining items are considered one after another in the processing loops after the second loop inclusive, in a retroacting manner. 
     At step  82 , it is judged as to whether a command object designating an update of the message has been found or not. If the command object designating the message update is found, the flow branches to step  83  (Yes) to eliminate this command object designating the message update, from the command queue  16  on the files. If a command object designating such a message update is not found, the flow branches to step  84  (No). 
     At step  84 , it is judged as to whether a treatment up to the final item, i.e., the oldest item in the command queue on the memory has been completed or not. This routine is terminated (Yes) if the final item has been treated, but the flow branchingly goes back to the step  81  if the final item has not been treated (No). 
     According to those processings at steps  81  through  84  as explained above, except for the latest command object designating a message update, the remaining command objects designating the update of the same message are eliminated from the command queue  16  on the files. Namely, even if a plurality of processings for updating a certain message have been performed, the pertinent forum can be updated to the latest contents by the latest command object only. As such, by eliminating those command objects from the command queue  16  which objects do not have any effects eventually, the quantity of information to be transmitted to other sites can be reduced. 
     FIG. 17 shows a subroutine for performing a command object processing according to forum deletion to be executed in the processing for optimizing information. 
     At step  91 , there is executed an initialization for setting a flag to “0”. This flag indicates as to whether the command queue on the memory is registered with a command object designating a forum creation, or not. 
     At step  92 , in the command queue on the memory, from the item next to the item which relates to the forum to be deleted, there is searched for an item having an object ID identical with that of the forum to be deleted. Namely, the item next to the item related to the deletee forum is considered in the first processing loop, and the remaining items are considered one after another in the processing loops after the second loop inclusive, in a retroacting manner. 
     At step  93 , it is judged as to whether the currently considering item is a command object designating a creation of the forum, or not. If it is such a forum creation, the flow branches to step  94  (Yes) to set the flag to “1”. If it is not such a forum creation, the flow branches to step  95  (No). 
     At step  95 , it is judged as to whether the currently considering item is a command object designating an update of the forum, or not. If it is such a forum update, the flow branches to step  96  (Yes) to eliminate, from the command queue  16  on the files, a command object designating the forum update. If it is not such a forum update, the flow branches to step  97  (No). 
     At step  97 , there is searched for a command object relating to a message included in the deletee forum, in the command queue on the memory. 
     At step  98 , it is judged as to whether a command object relating to a message included in the deletee forum has been found or not. If the command object relating to the message included in the deletee forum is found, the flow branches to step  99  (Yes) to eliminate this command object relating to the message, from the command queue  16  on the files. If a command object relating to the message is not found, the flow branches to step  100  (No). 
     At step  100 , it is judged as to whether a treatment up to the final item, i.e., the oldest item in the command queue on the memory has been treated or not. The flow branches to step  101  (Yes) if the final item has been treated, but branchingly goes back to the step  92  if the final item has not been treated (No). 
     At step  101 , it is judged as to whether the flag is “1” or not, i.e., whether a command object designating a creation of the forum existed in the command queue on the memory or not. If the flag is “1”, the flow branches to step  102  (Yes), to eliminate the command objects designating forum creation and deletion, respectively, from the command queue  16  on the files. If the flag is “0” (No), this routine is terminated. 
     According to those processings at steps  91  through  102  as explained above, if the command queue  16  on the files includes a command object designating a forum deletion, it can be decided that no affects are eventually made by an update processing of the forum to be executed before deletion of the forum. Thus, by eliminating, from the command queue  16  on the files, those command objects designating such forum update, the information quantity to be transmitted toward other sites is reduced. Contrary, if any command objects designating creation of the forum are not found in the command queue  16 , it can be decided that a creation of the forum at issue has been already performed. In this case, it is not performed to eliminate from the command queue  16  a command object designating a forum deletion, to thereby avoid disadvantage. Further, a deletion of forum does mean a deletion of those messages included in this deletee forum. Thus, by eliminating command objects related to such messages, the information quantity to be transmitted toward other sites is further reduced. 
     FIG. 18 shows a subroutine for performing a queue processing according to forum update to be executed in the processing for optimizing information. 
     At step  111 , in the command queue on the memory, from the item next to the item which relates to the forum to be updated, there is searched for an item, which has an object ID identical with that of the forum to be updated, and which designates an update of the forum. Namely, the item next to the item related to the updatee forum is considered in the first processing loop, and the remaining items are considered one after another in the processing loops after the second loop inclusive, in a retroacting manner. 
     At step  112 , it is judged as to whether a command object designating such a forum update has been found or not. If the command object designating the forum update is found, the flow branches to step  113  (Yes) to eliminate this command object designating the forum update, from the command queue  16  on the files. If a command object designating such a forum update is not found, the flow branches to step  114  (No). 
     At step  114 , it is judged as to whether a treatment up to the final item, i.e., the oldest item in the command queue on the memory has been completed or not. This routine is terminated (Yes) if the final item has been treated, but the flow branchingly goes back to the step  111  if the final item has not been treated (No). 
     According to those processings at steps  111  through  114  as explained above, except for the latest command object designating a forum update, the remaining command objects designating the update of the forum are eliminated from the command queue  16  on the files. Namely, even if a plurality of processings for updating a certain forum have been performed, the pertinent forum can be updated to the latest contents by the latest command object only. As such, by eliminating those command objects from the command queue  16  which objects do not have any effects eventually, the quantity of information to be transmitted to other sites can be reduced. 
     Thus, according to the processing for optimizing information shown in FIGS. 14 through 18, the quantity of information to be transmitted to other sites can be remarkably reduced without any disadvantage concerning information transmission, resulting in a drastic improvement in transmission efficiency. 
     FIG. 19 shows a processing for assuring an information sequence, to be executed when the communicative information is taken out and transmitted in each of the sites. 
     At step  120 , there is initialized a control table (transmission state registration device, transmission state registration process, and transmission registration function). Namely, the control table is registered with those sites which the information could not be transmitted to, such as due to trouble of the communication line  40  at the time of transmission. The processing at step  120  corresponds to initializing device. 
     At step  121 , one of the command objects is read out from the transmission queue  18 , to obtain a transmittee-destination for specifying a destination. Concerning this reading out of command objects, the latest item is read out in the first processing loop, and the remaining items are read out one after another in the processing loops after the second loop inclusive, in a retroacting manner, or in the older direction or sequence. 
     At step  122 , it is judged as to whether the obtained destination is registered in the control table or not. The flow branches to step  126  (Yes) if the destination is registered in the control table, and to step  123  (No) if the destination is not registered in the control table. The processing at step  122  corresponds to skipping device, skipping process, and skipping function. 
     At step  123 , the communicative information is transmitted via communication line  40  toward the destination obtained from the command object. 
     At step  124 , it is judged as to whether the transmission has failed or not. If the transmission has failed, the flow branches to step  125  (Yes) to register the failed destination into the control table. Contrary, the flow branches to step  126  (No), if the transmission has succeeded. It is noted that the communicative information of failed transmission is not deleted from the transmission queue  18 , and its transmission is tried again in the next processing. The processing at step  124  corresponds to error detection device, error detection process and error detection function. The processing at step  125  corresponds to registration controlling device, registration controlling process and registration controlling function. 
     At step  126 , it is judged as to whether all of the command objects in the transmission queue  18  have been treated or not. This routine is terminated if all of the command objects have been treated (Yes), but the flow branchingly goes back to step  121  if all of the command objects have not been treated (No). 
     According to the above explained processing of steps  120  through  126 , there are registered those destinations, the communicative information transmission to which have failed, into the control table. Further, for those destinations to which the transmissions have failed, the communicative informations are not transmitted and not deleted from the transmission queue  18 . Thus, even in case that the communicative information has not been transmitted such as due to trouble of the communication line  40 , the sequence of informations is assured, to avoid occurrence of disadvantage. As an additional effect, no transmissions are performed during the current transmission processing, toward those destinations in which communication errors have occurred. Thus, useless transmissions can be omitted, attaining reduction in occupancy time of the communication line  40 . Those communicative informations, which have not been transmitted during the current processing, are tried to be transmitted in the next processing after lapse of a predetermined time of period. This is because, such as trouble of the communication line  40  may be recovered by the lapse of the predetermined time of period. 
     FIGS. 20 through 23 show those processings which are executed when one of the communicative informations is taken out from the reception queue  20  at the background of the server  10  at each site. 
     FIG. 20 shows a main routine. 
     At step  130 , one of the communicative informations is taken out from the reception queue  20 . 
     At step  140 , there is called a subroutine (FIG. 21) for performing a processing for checking destination inconsistency. 
     At step  150 , there is called a subroutine (FIG. 22) for performing a processing for checking inconsistency in information contents. 
     At step  170 , there is called a subroutine (FIG. 23) for performing a registration processing to the database  12 . 
     FIG. 21 shows the subroutine for performing the processing for checking destination inconsistency. 
     At step  141 , there are analyzed those objects ID&#39;s which are included in one communicative information taken out from the reception queue  20 , to thereby obtain a transmitter site and a treatee forum (forum to be treated). 
     At step  142 , it is checked as to whether the transmitter site obtained at step  141  exists in the destination-information for the treatee forum registered in the database  12 , or not. 
     At step  143 , there is performed a branching processing. Namely, this routine is terminated if the transmitter site exists in the destination-information of the treatee forum (Yes). Contrary, the flow branches to step  144  if the transmitter site does not exist in the destination-information for the treatee forum (No). 
     At step  144 , the transmitter site obtained at step  141  is additionally registered into the destination-information for the treatee forum registered in the database  12 . It is possible, together with this processing, such as to indicate to the client  30  that an inconsistency has occurred in the destination so that the administrator of the electronic conference system can recognize the occurrence of inconsistency, at an early stage. 
     The processings at steps  141  through  143  correspond to the destination inconsistency judgment device, process and function. Further, the processing at step  144  corresponds to the destination inconsistency correction device, process and function. 
     According to the processings at steps  141  through  144  as explained above, automatically performed based on the communicative information are the inconsistency judgment and inconsistency correction of destination-information, even when an inconsistency has occurred in the destination-information at a certain site due to a certain reason. Thus, there is avoided an occurrence of such a situation that the information to be transmitted is not transmitted. As a result, the reliability of the electronic conference system can be considerably improved. 
     FIG. 22 shows a subroutine for performing a processing of inconsistency check for information contents. 
     In this respect, inconsistency in information contents occurs such as in the following cases. It is now assumed that the electronic conference system is constituted of sites A, B, C, D and E. Further, there are considered the information transmission paths in which the informations are transmitted from the site A to the site C via the site B, and from the site A to the site E via the site D, respectively. In this case, there may occur such a situation that the database  12  at the site D is recovered based on a recovery disk, but the database  12  returns, due to oldness of the recovery disk, to a state in which the site E is not registered as an information-exchange-destination of the site D. Then, the information is not transmitted from the site D to the site E. However, it is likely that the users of the site E do not find out that the information is not transmitted, resulting in failure of transmission of important information. 
     Thus, it is attained to improve the reliability of the electronic conference system, by automatically judging and correcting an occurrence of inconsistency in information contents, making use of inconsistency check processing for information contents, to be explained hereinafter. 
     At step  151 , by analyzing the appropriate object ID included in the communicative information taken out from the reception queue  20 , it is judged as to whether the processing is a forum creation, or not. This routine is terminated if it is the forum creation (Yes), but the flow branches to step  152  if it is not a forum creation (No). 
     At step  152 , there is obtained an object ID of a treatee forum, by analyzing object ID&#39;s included in the communicative information which has been taken out from the reception queue  20 . Namely, there is performed a processing such as creation or update of objects, for the forum which is designated by the obtained object ID of the forum. 
     At step  153 , it is judged as to whether the treatee forum exists in the database  12 , or not. The flow branches to step  155  if the forum exists (Yes), or to step  154  if the forum does not exist (No). 
     At step  154 , it is judged as to whether the object ID of treatee forum exists in the deletion information to be explained later, or not. This routine is terminated if the object ID of forum exists in the deletion information (Yes). If the object ID of forum does not exist, it is judged that an inconsistency has occurred in the information contents, so that the flow branches to step  162  (No). 
     The deletion information is an information for specifying a deleted object, in case that a deletion treatment of object is performed for the database  12  of a certain site. Concretely, a deletion information is created on the database  12 , and registered with an object ID for specifying the deleted object. In case that the object ID of the treatee forum exists in the deletion information, the forum has been deleted before information transmission thereto from other sites. Thus, it can be judged that no inconsistency in information has occurred. The same consideration can be adopted, in case that the treatee target is a message. 
     At step  155 , by analyzing the appropriate object ID included in the communicative information taken out from the reception queue  20 , it is judged as to whether the processing is a topic creation, or not. This routine is terminated if it is the topic creation (Yes), but the flow branches to step  156  if it is not a topic creation (No). 
     At step  156 , there is obtained an object ID of a treatee topic, by analyzing the appropriate object ID included in the communicative information taken out from the reception queue  20 . 
     At step  157 , it is judged as to whether the treatee topic exists in the treatee forum, or not. The flow branches to step  159  if the topic exists (Yes), or to step  158  if the topic does not exist (No). 
     At step  158 , it is judged as to whether the object ID of treatee topic exists in the deletion information, or not. This routine is terminated if the object ID of topic exists in the deletion information (Yes). If the object ID of topic does not exist, it is judged that an inconsistency has occurred in the information contents, so that the flow branches to step  162  (No). 
     At step  159 , there is obtained an object ID of a “parent message of the treatee message” (hereinafter merely called “parent message”), by analyzing an appropriate object ID included in the communicative information taken out from the reception queue  20 . 
     At step  160 , it is judged as to whether the parent message designated by the obtained parent message ID exists in the treatee forum, or not. This routine is terminated if the parent message exists (Yes), or the flow branches to step  161  if the parent message does not exist (No). 
     At step  161 , it is judged as to whether the object ID of treatee parent message exists in the deletion information, or not. This routine is terminated if the object ID of parent message exists in the deletion information (Yes). If the object ID of parent message does not exist, it is judged that an inconsistency has occurred in the information contents, so that the flow branches to step  162  (No). 
     At step  162 , there is obtained an object ID designating a transmitter site, by analyzing the appropriate object ID included in the communicative information. Further, there is obtained the whole of treatee forum from the transmitter site, by specifying the transmitter site based on the obtained object ID. 
     At step  163 , there is conducted an update registration of the database  12 , while merging the forums registered in the database  12  with the forum obtained from the transmitter site. 
     According the above explained processings at steps  151  through  163 , it is judged that an inconsistency has occurred in the information contents, if the treatee target object designated by the communicative information is not registered in the database  12  and does not exist in the deletion information, in case that the treatment content is not a forum creation nor topic creation. If it is judged that an inconsistency in the information contents has occurred, there is obtained the whole of forum from the transmitter site and there is conducted an update treatment for the database  12  together by mergence, to thereby correct the information contents. Thus, an inconsistency in the information contents can be automatically judged and corrected, so that the reliability of the electronic conference system can be also improved. 
     FIG. 23 shows a subroutine for performing a registration processing to the database. 
     At step  171 , there is obtained a type of operation (classification of creation, deletion, update or move of object; the same rule applies correspondingly to the following), by analyzing the appropriate object ID included in the communicative information taken out from the reception queue  20 . 
     At step  172 , it is judged as to whether the operation type is an object creation, or not. The flow branches to step  173  if it is the object creation (Yes), or to step  179  if it is not an object creation (No). 
     At step  173 , it is judged as to whether the createe object already exists in the database  12 , or not. The flow branches to step  174  if already exists (Yes), or to step  178  to create the object if not exists yet (No). 
     At step  174 , there is retrieved an ID of parent object of the createe object, from the database  12 . 
     At step  175 , the retrieved parent object ID is compared with the parent object ID included in the communicative information, i.e., creation information. 
     At step  176 , it is judged as to whether the retrieved parent object ID is identical with the parent object ID included in the communicative information, or not. This routine is terminated if the parent object ID&#39;s are identical with each other (Yes), but the flow branches to step  177  if the parent object ID&#39;s are not identical (No). 
     At step  177 , there is performed an object move processing. Namely, in this object move processing, the createe object, which already exists, is moved to a lower level of the parent object designated by the transmitted creation information. 
     At step  179 , it is judged as to whether the operation type is a deletion of object, or not. The flow branches to step  180  if it is the object deletion (Yes), or to step  184  if it is not an object deletion (No) to execute a processing corresponding to the operation type. 
     At step  180 , there is obtained an ID of parent object of the deletee object, from the database  12 . 
     At step  181 , the obtained parent object ID is compared with the parent object ID included in the communicative information. 
     At step  182 , it is judged as to whether the obtained parent object ID is identical with the parent object ID included in the communicative information, or not. The flow branches to step  183  if the parent object ID&#39;s are identical with each other (Yes), to perform an object deletion. Contrary, this routine is terminated while neglecting the command object, if the parent object ID&#39;s are not identical (No). 
     According to the above explained processings of steps  171  through  184 , even in case of an object move between forums having information transmission paths different from each other, the object deletion and the object creation are executed at the move origination of the object and at the move destination of the object, respectively. As a result, regardless of the sequence of information transmission, the object move can be assuredly carried out. 
     FIG. 24 shows an update processing for a recovery information. 
     At step  190 , there is obtained a type of operation, by analyzing the appropriate object ID included in the communicative information taken out from the reception queue  20 . 
     At step  191 , it is judged as to whether the operation type is an object creation, or not. If it is the object creation (Yes), the flow branches to step  192  to record, to a recovery disk, an object ID designating a createe object, and a destination-information designating its information-exchange-destination. The flow branches to step  193 , if it is not an object creation (No). 
     At step  193 , it is judged as to whether the operation type is an object deletion or not. If it is the object deletion, the flow branches to step  194  (Yes) to delete from the recovery disk: the object ID designating the deletee object; and the destination-information designating its information-exchange-destination. If it is not an object deletion (No), this routine is terminated. 
     According to the above explained processings at steps  190  through  194 , the update of recovery disk is performed whenever such as an object creation is effected onto the database  12 , so that the recovery disk is continuously kept at the latest state. In this concern, the recovery disk is recorded with not an object body itself but an object ID which designates such an object body, so that the update of recovery disk is quickly carried out. Thus, the response speed of the electronic conference system is never decreased. 
     In this embodiment, the update of recovery disk is executed whenever such as creation of object is performed to the database  12 . However, it is possible that the update of recovery disk is executed according to instructions such as of the administrator of the electronic conference system, as will be described later. Further, it is advisable that the recovery disk is to be prepared in a manner physically different from the disk which constitutes the database  12 . 
     FIG. 25 shows an update processing of the recovery disk. This update processing of recovery disk is executed such as by the instructions of the administrator of electronic conference system. 
     At step  200 , there are searched for all of the forums registered in the database  12 . 
     At step  201 , there are obtained those destinations which are information-exchange-destinations of the searched forums, and those object ID&#39;s, which designate these forums. Further, the obtained destinations and object ID&#39;s are registered into the recovery disk. 
     At step  202 , there are searched for all of the messages included in the searched forums. 
     At step  203 , the object ID&#39;s designating all of the searched messages are registered into the recovery disk. 
     According to the processing at steps  200  through  203  as explained above, upon update instructions such as from the administrator of the electronic conference system, there are recorded into the recovery disk, the destinations and object ID&#39;s of forums and the object ID&#39;s of messages included in the forums which are registered in the database  12 . Namely, the recovery disk is recorded with not the true bodies of objects but the object ID&#39;s designating the objects, so that the update of recovery disk can be quickly carried out. Thus, regardless of the quantity of information, the administrator of the electronic conference system is allowed to conduct the update of recovery disk at appropriate time points, to thereby keep it at the latest state. 
     FIG. 26 shows a recovery processing of the database  12 . This recovery processing of database  12  is executed such as by the instructions of the administrator of electronic conference system. 
     At step  210 , there is searched for the ID of forum registered in the recovery disk. 
     At step  211 , there are read out ID&#39;s of destinations which are information-exchange-destinations recorded in the recovery disk, and there is connected to the site which is specified by the read out ID of destination. Namely, in case that the ID&#39;s of destinations of forum A are the sites A and B, there is connected to the site A or to the site B. The connectee site may be determined such as in view of the vacancy or availability of the communication line  40 . 
     At step  212 , there are obtained all of the objects included in the forum searched for at step  210 , from the connected site. 
     At step  213 , there are deleted, from the obtained objects, those objects which are not registered in the recovery disk. 
     At step  214 , it is judged as to whether all of the ID&#39;s of forums registered in the recovery disk have been processed or not. This routine is terminated, if all of the ID&#39;s of forums have been processed (Yes). Contrary, the flow branchingly goes back to step  210  to repeat the processings of steps  210  through  213 , if all of the ID&#39;s of forums have not been processed (No). 
     According to the processing at steps  210  through  214  as explained above, upon instructions to conduct a recovery of the database  12  such as from the administrator of the electronic conference system, there is obtained the whole of the required forum from other site via communication line  40 . Further, there are deleted, from the obtained forums, those objects which are not registered in the recovery disk. This is because, there remains such a possibility that an operation at a certain site is not reflected to other site, due to the adoption of the store-and-forward type of communication system. 
     Based on the above, the database can be rapidly recovered to the state at the time of update of the recovery disk, i.e., the state just before the occurrence of trouble. 
     The recovery processing of the database  12  may be executed such that the objects included in a forum are obtained from other site after creating the forum based on the information registered in the recovery disk. 
     If those programs, which attain each of the above explained functions, respectively, are recorded in a medium such as paper card (punch card), paper tape, magnetic tape, magnetic disk, magnetic drum, IC card, or CD-ROM, it becomes possible to distribute the information transmission program according to the present invention. Then, those, who have obtained such a medium, can easily constitute the information transmission apparatus, making use of a general electronic computer.