I had to give a quick explanation of how Moodle works to a group of non-developers at the OU. This was my attempt.

1. A ‘lies to children’ introduction to how Moodle works http://en.wikipedia.org/wiki/Lie-to-children

2. UI Libraries DB libs DB User HTTP PHP function calls PHP function calls SQL Moodle Using a web browser Moodle follows a fairly classic three-layer architecture. But it is not strongly enforced. Developers can make a mess if they try. File libs Files moodledata

3. Core UI Libs (formslib, commenting, YUI, …) Core libraries (for handling roles, categories, courses, users, …) DB libs File libs Forum UI Quiz UI … Plugins Moodle core Core UI roles, categories, courses, users, … Forum lib Quiz lib … Core data Forum data Quiz data Plugins implement specific functionality. They slice through all three layers. The use the facilities provided by Moodle core.

6. Being a Student does let you attempt quizzes Is Paul allowed to attempt Quiz 1? User (Paul) Context (Course PM100) Context (Category OUBS) Context (Site OU VLE) Capability (Attempt quiz) Role (Logged-in) Role (Student) Paul is logged in to the VLE Paul is a student in PM100 Just being logged-in does not let you attempt quizzes So: Paul can do this quiz  Context (Activity Quiz 1)