Abstract: In order to perform format conversion between the formats of a plurality of files without any work by a user, a file system stores a relation between a conversion originating file and a conversion destination file, and synchronously with an issue of a file operation API, the format conversion processes are executed. A user performs only the tasks essential for an application, without taking into consideration various necessary format conversions (either one-step or multi-step). During the user task, it is not necessary to designate a conversion originating file and a timing of format conversion. A user can use always a latest conversion destination file.

Abstract: Information management system on the WWW for improving the compatibility of metadata on the WWW, locally managing metadata, which is dispersed, in a manner facilitating search, and thus improving efficiency and precision in search. Domain administration servers are included for acquiring metadata, which is dispersedly saved in servers interconnected over a computer network, from associated managing domains. Each domain administration server includes a metadata management database in which acquired data is recorded, and a search engine that searches the database. The search engine searches the database in response to a query that specifies as known data an identifier, that is, a URI of a resource and an attribute name of the resource, and returns an attribute value as the result of search.

Abstract: In order to perform format conversion between the formats of a plurality of files without any work by a user, a file system stores a relation between a conversion originating file and a conversion destination file, and synchronously with an issue of a file operation API, the format conversion processes are executed. A user performs only the tasks essential for an application, without taking into consideration various necessary format conversions (either one-step or multi-step). During the user task, it is not necessary to designate a conversion originating file and a timing of format conversion. A user can use always a latest conversion destination file.

Abstract: In order to perform format conversion between the formats of a plurality of files without any work by a user, a file system stores a relation between a conversion originating file and a conversion destination file, and synchronously with an issue of a file operation API, the format conversion processes are executed. A user performs only the tasks essential for an application, without taking into consideration various necessary format conversions (either one-step or multi-step). During the user task, it is not necessary to designate a conversion originating file and a timing of format conversion. A user can use always a latest conversion destination file.

Abstract: In order to perform format conversion between the formats of a plurality of files without any work by a user, a file system stores a relation between a conversion originating file and a conversion destination file, and synchronously with an issue of a file operation API, the format conversion processes are executed. A user performs only the tasks essential for an application, without taking into consideration various necessary format conversions (either one-step or multi-step). During the user task, it is not necessary to designate a conversion originating file and a timing of format conversion. A user can use always a latest conversion destination file.

Abstract: In order to effectively make the grasp of operating conditions of a plurality of servers and a cache management in an information system without increasing a time/labor taken by an administrator, the plurality of servers forms a multi-cast hierarchy dynamically reconstructed by virtue of mutual support and the communication of server status, cache directory and validation is performed on the hierarchy. The administrator has not a need of management for cooperation between servers excepting the designation of some other servers for startup thereof. A cache between servers is shared through the exchange of a cache directory and a validation time is reduced, thereby shortening the response time for users.

Abstract: In order to perform format conversion between the formats of a plurality of files without any work by a user, a file system stores a relation between a conversion originating file and a conversion destination file, and synchronously with an issue of a file operation API, the format conversion processes are executed. A user performs only the tasks essential for an application, without taking into consideration various necessary format conversions (either one-step or multi-step). During the user task, it is not necessary to designate a conversion originating file and a timing of format conversion. A user can use always a latest conversion destination file.

Abstract: Irregular and unstable natures of the Internet to be caused by an increase in Internet accessing users are alleviated and services of an information system more comfortable to users are provided. To this end, each servers among a plurality of servers cooperating to provide services stores the past communications line state (throughput and latency), and in accordance with the stored communications lines state, cache reference and prefetch are preformed between optional servers.