Patent ID: 6219818
Filing Date: 2001-04-17
Classification: G06F,Y10S

Abstract:
A change-detection web server comprising:a network connection for transmitting and receiving packets from a remote client and a remote document server;a responder, coupled to the network connection, for communicating with the remote client, the responder registering a document for change detection by receiving from the remote client a uniform-resource-locator (URL) identifying the document, the responder fetching the document from the remote document server and generating an original checksum for a checked portion of the document, the checked portion being less than the entire document;archival storage means, coupled to the responder, for receiving the URL and the original checksum from the responder when the document is registered by the remote client, the archival storage means for storing a plurality of records each containing a URL and a checksum for a registered document;a periodic fetcher, coupled to the archival storage means and the network connection, for periodically re-fetching the document from the remote document server by transmitting the URL from the archival storage means to the network connection, the periodic fetcher receiving a fresh copy of the document from the remote document server,a checksum generator, coupled to receive the fresh copy of the document from the periodic fetcher, for generating a fresh checksum of a portion of the fresh copy of the document and comparing the fresh checksum to the original checksum, the checksum generator signaling a detected change to the remote client when the fresh checksum does not match the original checksum,whereby a change in the document is detected by comparing a checksum for the checked portion of the document, wherein changes in portions of the document outside the checked portion are not signaled to the remote client.