title: what is the difference between semaphore and critical region?
body: <p>the only thing i understood is </p>
  
  <ul>
  <li>semaphore is a primitive way</li>
  <li>critical region has a GUARD variable  (semaphore also does but the name is not GUARD!)</li>
  </ul>
  
  <p>??</p>
  
  <p>so whats the difference?</p>