A method and system for updating an archive of a computer file to reflect changes made to the file includes selecting one of a plurality of comparison methods as a preferred comparison method. The comparison methods include a first comparison method wherein the file is compared to an archive of the file and a second comparison method wherein a first set of tokens statistically representative of the file is computed and compared to a second set of tokens statistically representative of the archive of the file. The method further includes carrying out the preferred comparison method to generate indicia of differences between the file and the archive of the file for updating the archive of the file.