Magento initialization steps

1. myMageStore.com is entered on a browser, the request is sent to the server.
2. The server runs the file index.php
3. index.php will try to load Mage.php

if it doesn’t exist, redirect to downloader of magento
else call Mage::run($mageRunCode, $mageRunType);

4. Mage::run($mageRunCode, $mageRunType) calls app/code/core/Mage/Core/Model/App::run($mageRunCode, $mageRunType)
6. App::run($mageRunCode, $mageRunType)

a. Loads config files in app/etc/modules
b. Loads config files in each module (app/code/core/Mage/Customer/etc/)
c. Update/create version of modules in core_resource
d. Update/create database of modules
e. Calls Mage_Core_Controller_Varien_Front::dispatch()

7. Mage_Core_Controller_Varien_Front::dispatch()

a. Uses routers to define the controller and action requested
b. Calls dispatch() of the controller that is requested
c. Calls action of the controller that is requested
d. Returns html page on the browser