title: What are "transactional" file operations?
body: <p>I was browsing the Win32 API functions for file and directory management operations. I saw that some of those functions has their so called "transactional" counterparts.</p>
  
  <p>Examples:<br>
  <a href="http://msdn.microsoft.com/en-us/library/aa363855%28v=vs.85%29.aspx" rel="noreferrer">CreateDirectory</a> and <a href="http://msdn.microsoft.com/en-us/library/aa363857%28v=vs.85%29.aspx" rel="noreferrer">CreateDirectoryTransacted</a><br>
  <a href="http://msdn.microsoft.com/en-us/library/aa365488%28v=vs.85%29.aspx" rel="noreferrer">RemoveDirectory</a> and <a href="http://msdn.microsoft.com/en-us/library/aa365490%28v=vs.85%29.aspx" rel="noreferrer">RemoveDirectoryTransacted</a><br>
  <a href="http://msdn.microsoft.com/en-us/library/aa363858%28v=vs.85%29.aspx" rel="noreferrer">CreateFile</a> and <a href="http://msdn.microsoft.com/en-us/library/aa363859%28v=vs.85%29.aspx" rel="noreferrer">CreateFileTransacted</a><br>
  <a href="http://msdn.microsoft.com/en-us/library/aa363851%28v=vs.85%29.aspx" rel="noreferrer">CopyFile</a> and <a href="http://msdn.microsoft.com/en-us/library/aa363853%28v=vs.85%29.aspx" rel="noreferrer">CopyFileTransacted</a></p>
  
  <p>I read explanations of these transacted functions, the Wikipedia article <a href="http://en.wikipedia.org/wiki/Transactional_NTFS" rel="noreferrer">Transactional NTFS</a> and <a href="http://msdn.microsoft.com/en-us/magazine/cc163388.aspx" rel="noreferrer">this MSDN Magazine page</a>. But because of the heavy terminology (for me) in these pages, I didn't clearly understand these explanations. They all come to a common consensus that these functions are "atomic". But as far as I understand from the word "atom", it is a nucleus with spinning electrons around it...</p>
  
  <p>Can you please explain me in basic and simple English sentences, what are the purposes and operations of these functions? Why and when would one prefer transacted version of an API function?</p>