title: How does PHP actually work?
body: <p>Is there some guide out there that describes how the PHP internals?</p>
  
  <ul>
  <li>How files are loaded (required, included)?</li>
  <li>How they are parsed and executed?</li>
  <li>How memory is allocated?</li>
  <li>How objects are created/destroyed?</li>
  <li>How external modules are loaded?</li>
  <li>How the stack/heap works?</li>
  <li>How opcode caching actually work?</li>
  <li>Common hacks and performance tips?</li>
  </ul>