Patent ID: 7222137
Filing Date: 2007-05-22
Classification: G06F,Y10S

Abstract:
1. A difference updating method comprising: a difference data reception step, with a difference data reception unit, receiving difference data of all the segments which is generated for each segment by dividing a new one of two old and new files into a plurality of segments of the same size and searching for a data row matching a data row in each segment within the range from the position which is one segment before the starting position of a target segment of the old file to the endmost of the old file and storing the received difference data into a nonvolatile memory; a restoration processing step, with a restoration processing unit, storing the restoration process segment number (X) indicative of a current process segment into the nonvolatile memory, thereafter restoring segment data from one segment of the difference data and storing the restored segment data into the nonvolatile memory; and an overwrite processing step, with an overwrite processing unit, storing the overwrite processing segment number (X−1) indicative of an immediately preceding process segment into the nonvolatile memory, thereafter reading from the nonvolatile memory the restored data which has been restored on the immediately preceding segment and overwriting the read restored data onto data to be rewritten in a nonvolatile memory.