title: How does Git save space and is fast at the same time?
body: <p>I just saw the first <a href="http://en.wikipedia.org/wiki/Git_%28software%29" rel="noreferrer">Git</a> tutorial at <a href="http://blip.tv/play/Aeu2CAI" rel="noreferrer">http://blip.tv/play/Aeu2CAI</a>.</p>
  
  <p>How does Git store all the versions of all the files, and how can it still be more economical in space than <a href="http://en.wikipedia.org/wiki/Apache_Subversion" rel="noreferrer">Subversion</a> which saves only the latest version of the code?</p>
  
  <p>I know this can be done using compression, but that would be at the cost of speed, but this also says that Git is much faster (though where it gains the maximum is the fact that most of its operations are offline).</p>
  
  <p>So, my guess is that</p>
  
  <ul>
  <li>Git compresses data extensively</li>
  <li>It is still faster because <code>uncompression + work</code> is still faster than <code>network_fetch + work</code></li>
  </ul>
  
  <p>Am I correct? Even close?</p>