Abstract: In a data communication method, when packet data are sent and received among a plurality of computers connected each other via the network, communications are established by using a unicast connection. Then, the packet data are sent by selectively using a multicast communication and the unicast communication for at least one computer to which the communication is established. As a result, it is possible to reduce an amount of network traffic under a peer-to-peer network without intermediation of a server and improve reliability of the multicast communication.

Abstract: A data communication method is used to exchange data among a plurality of computers which are mutually coupled via a network. Each of the computers has a program which causes the computer to have a communicating function to transmit and receive data to and from one or more other computers, a data processing function to process data which are transmitted and received, and an output function to output data to an output section depending on a process of the data processing function. The data communication method includes a storing step to store data received by the communicating function by the data processing function in one computer when receiving data from one or more other computers by the communicating function, and a mode judging step to judge whether or not to output the received data to the output function of the one computer depending on a mode attribute of the received data and a communication mode of the one computer.

Abstract: A technique is disclosed for enabling collaborative creation of a document by plural persons. The collaborative document creation involves setting an editing method for a document created by a first terminal apparatus, setting an editing function for realizing the editing method to the document created by the first terminal apparatus, and disclosing to a second terminal apparatus the document created by the first terminal apparatus with the editing function set thereto.

Abstract: An electronic document producing, distributing and accessing system prevents a malicious program from being mixed into an electronic document without being influenced by an operating environment of a computer by providing a document producing application and a document accessing application by the same application provider. In the electronic document having an encapsulated document structure, a document information file stores document information that is a substance of expression of a document. An operating program file stores an operating program that materializes the document information, a limitation being given to the operating program by a security function when the operating program is interpreted and executed by a computer. The document information file and the operating program file are encapsulated as a single document.

Abstract: A data communication method is used to exchange data among a plurality of computers which are mutually coupled via a network. Each of the computers has a program which causes the computer to have a communicating function to transmit and receive data to and from one or more other computers, a data processing function to process data which are transmitted and received, and an output function to output data to an output section depending on a process of the data processing function. The data communication method includes a storing step to store data received by the communicating function by the data processing function in one computer when receiving data from one or more other computers by the communicating function, and a mode judging step to judge whether or not to output the received data to the output function of the one computer depending on a mode attribute of the received data and a communication mode of the one computer.

Abstract: In a data communication method, when packet data are sent and received among a plurality of computers connected each other via the network, communications are established by using a unicast connection. Then, the packet data are sent by selectively using a multicast communication and the unicast communication for at least one computer to which the communication is established. As a result, it is possible to reduce an amount of network traffic under a peer-to-peer network without intermediation of a server and improve reliability of the multicast communication.

Abstract: In a file structure, it is possible to properly assist a user of a computer to operate a file without the use of an extension of the file and overcome some problems caused by the difference of the development time between an operating system and application programs in the computer. In the file structure, a file comprises file content information formed of a program code or data processed by the computer and a management program code performing processes for assisting the user to operate the file corresponding to the file content information. Unlike conventional file creation and display methods depending on the extension, it is possible to properly aid user's file operations such as a file selection by calling the management program code from the operating system.

Abstract: An encapsulated document includes digital information files of substance of document, a display information file for indicating a display state of the digital information files on the document, an operation program file read and executed by a computer for displaying the information files according to the display state indicated by the display information file. The digital information files and operation program files are encapsulated into one document.