title: Change Journal for Blocks in Windows(NTFS)
body: <p>I have written a backup tool that is able to backup files and images of volumes for Windows. To detect which files have changed I use the Windows Change Journal. I already use the shadow copy functionality to do a consistent copy of both the files and the volume images.</p>
  
  <p>To detect which blocks have changed I use hashes at the moment. This means the whole volume has to be read once (because to see which block has changed hashes of all blocks have to be calculated).
  The backup integrated into Windows 7 is able to create incremental volume images without checking all blocks. I wasn't able to find an API for a kind of block level change journal.</p>
  
  <p>Does anybody know how to access this information?
  (I'm willing to dive deep into NTFS internals - even reading and parsing special files)</p>