Get to Know Code Igniter -- 1

first of all, sorry for disapear almost 2 years even if there is nobody waiting here but at least it must be a waste of  the space resource.
recently i'm involved in PHP development, now let's start to introduce an easy use toolkit - code igniter. it's a light weight, open source and MVC based framework runs on php4 with simple footprint.

1. Install
a.Download it from: http://www.codeigniter.com/download_files/CodeIgniter_1.6.3.zip
b.Unzip it to your sever
c.Open the application/config/config.php file with a text editor and set your base URL.
d.Open the application/config/database.php file with a text editor and set your database settings.

2. Principle











a.The index.php serves as the front controller, initializing the base resources needed to run CodeIgniter.
b.The Router examines the HTTP request to determine what should be done with it.
cIf a cache file exists, it is sent directly to the browser, bypassing the normal system execution.
d.Security. Before the application controller is loaded, the HTTP request and any user submitted data is filtered for security.
e.The Controller loads the model, core libraries, plugins, helpers, and any other resources needed to process the specific request.
f.The finalized View is rendered then sent to the web browser to be seen. If caching is enabled, the view is cached first so that on subsequent requests it can be served.