title: What does it mean to run a virtual OS in "headless mode"?
body: <p>I've been hearing a lot about about how the new version of VMWare Fusion can run virtual operating systems in "headless mode". </p>
  
  <p>A Google search makes it clear that other virtualisation products also have similar features, however, I have not been able to find a good description of what this actually means? What is happening when you do this?</p>