US Patent 7499930 Data processing apparatus, data processing method, and data processing program

This invention provides a technique that deletes data at high speed, and prevents discontinuous cluster chains from being produced due to data deletion. To accomplish this, when data included in the data file is partially deleted from the head of the data file, the location of header information is moved for respective clusters, and the size of the header information is changed, so as to start head data after data deletion from the location immediately after the moved header information.