Patent ID: 7404201
Filing Date: 2008-07-22
Classification: G06F,H04N

Abstract:
1. A network system, comprising: a distribution computer including a distribution storage device; a distribution request computer configured to issue a send request to obtain contents stored in said distribution storage device; a plurality of copy computers, each copy computer including a copy storage device configured to store as copy contents a copy of selected contents of said contents stored in said distribution storage device, the distribution computer being configured to designate a selected one of the plurality of copy computers to store a copy of the selected contents in the storage device under control thereof, the plurality of copy computers being located at positions closer to the distribution request computer than the distribution computer; and a search computer in communication with the distribution computer and one of the plurality of copy computers, the search computer including a contents search module configured to send a contents search request to the first copy computer based on said send request, wherein each copy computer further includes a server list configured to store information indicating another copy computer, wherein the distribution computer further includes a contents registration module which, when the contents in the distribution storage device are updated, sends a copy request and copy contents of the updated contents to the designated one of said plurality of copy computers, the copy request giving an instruction to create the copy contents in the copy storage device of the designated copy computer, wherein, when receiving a copy request from the distribution computer, the copy computer receiving the request creates a copy of the updated contents in the storage device under control thereof, wherein, when receiving a send request from said distribution request computer, the search computer sends a contents search request to the one of the plurality of copy computers, wherein, when receiving the contents search request from the search computer, the copy computer receiving the request searches the copy storage device under control thereof to determine whether a copy of the contents being searched exists in the copy storage device, returns the copy of the contents to the search computer if the copy of the contents exists, determines whether the information indicating another copy computer of the plurality of copy computers is stored in the server list if the copy of the contents does not exist, forwards the contents search request to the another copy computer indicated by the information if the information is stored in the server list, and sends an error notification to the search computer if the information is not stored in the server list, wherein the search computer sends the contents to the distribution request computer upon receiving the contents from the copy computer, wherein the search computer sends the send request to the distribution computer upon receiving the error notification from the copy computer, wherein the contents registration module sends the copy request and the copy contents to the designated one of the plurality of copy computers when receiving the send request from the search computer, wherein said send request issued by said distribution request computer is based on a transmission protocol selected from HTTP and RTSP, wherein each of the distribution computer, search computer, and plurality of copy computers include a distribution module programmed to communicate using a distribution protocol that is independent of the transmission protocol, such that contents are able to be written to, and read from, said distribution storage device regardless of a difference between the transmission protocol and the distribution protocol and without setting a disk capacity for each server application accessing said contents, wherein the distribution computer further periodically activates the contents registration module to determine whether new contents are to be stored from a storage device, and when new contents are to be stored, read the new contents and send the new contents and a contents registration request to the plurality of copy computers, and wherein the contents registration module when activated controls a time to send the new contents to the plurality of copy computers according to one of a state of the network system and a type of the new contents.