A novel software updating method is provided. A target file is divided into segments, where some segments are updated by patching, while other segments are updated by archiving. The segmentation of the update allows very large files such as DYLD shared caches to be patched in-place, i.e., by using free space available within the file to perform patching rather than requiring enough free space on disk to store both the new version and the old version of the file. The segmentation of the update also allows each segment to be updated individually by the most optimal update method (copy, patch, or archive) so that the size of the update file can be minimized.