File synchronization (or syncing) in computing is the process of ensuring that computer files in two or more locations are updated via certain rules.In one-way file synchronization, also called mirroring, updated files are copied from a 'source' location to one or more 'target' locations, but no files are copied back to the source location. In two-way file synchronization, updated files are copied in both directions, usually with the purpose of keeping the two locations identical to each other.