title: Synchronizing file system, how to detect if a file has changed?
body: <p>I have the needs to write a simple backup component to synchronize a folder and its sub folders to a server. For incremental backup I only want to upload the changed files. What would be the best way to track the changes in the file system? Some existing software like tortoisesvn and office groove have such capability to detect file changes. I wonder what is the best way to implement a similar thing. </p>
  
  <p>Thanks!</p>