How does Drupal work?
A. Drupal is written in the PHP programming language and consists of a core Content Management System that stores content in a MySQL database and keeps track of users and permissions. This core functionality is extended by modules which are like plugins or extensions. They can be easily loaded into Drupal and automatically modify the database and add administration screens and functionality. Drupal is not a web server so it needs Apache, nginx (which is what we use), lighthttpd or some other web server which mediates the browser to web server connection. The web server executes Drupal’s index.php file using a PHP engine. From there, many Drupal PHP files will be called, as many as are required by the nature of the request made by the browser. This is referred to as the Drupal bootstrap process. After executing all necessary PHP files and database queries, Drupal presents the web server with a response to send to the browser.
