Patent ID: 6574657
Filing Date: 2003-06-03
Classification: G06F,Y10S

Abstract:
A method for a server computer to generate an update file for transmission to a client computer that permits the client computer to generate a copy of a current version of a subscription file comprised of a first plurality of file segments from a copy of an earlier version of the subscription file comprised of a second plurality of file segments, such that each file segment corresponds to a portion of its respective subscription file, the method comprising the steps of:for each segment of the current version of the subscription file, (a) searching an earlier version of a signature list corresponding to an earlier version of the subscription file for an old segment signature which matches a new segment signature corresponding to the segment; (b) if step (a) results in a match, writing a command in the update file for the client computer to copy an-old segment of the client computer's copy of the earlier version of the subscription file into the client computer's copy of the current version of the subscription file, wherein the old segment corresponds to the segment for which a match was detected in step (a); and (c) if step (a) results in no match, writing a command in the update file for the client computer to insert a new segment of the current version of the subscription file into the client computer's copy of the current version of the subscription file; wherein the new segment of the current version of the subscription file is written into the update file and the unchanged segment is excluded from the update file; and wherein steps (a) through (c) are performed by the server computer, without interaction with the client computer, in response to the server computer detecting a change between the current version of the subscription file and the earlier version of the subscription file.