title: When exactly PHP interpreter is launched?
body: <p>So, when exactly PHP interpreter is working?</p>
  
  <p>As I understood, the flow is something like this:</p>
  
  <p>Request -> CGI ( e.g php-fpm ) or server module ( e.g mod_apache ) -> server -> output</p>
  
  <p>Is it run by interfaces/modules? If yes, does it mean that it is inside those interfaces/modules? Or somewhere else?</p>