http://pecl.php.net/package/APC
http://php.net/manual/en/book.apc.php
http://www.lecentre.net/blog/archives/1311
http://rtcamp.com/wordpress-nginx/tutorials/php/apc-cache-with-web-interface
http://www.if-not-true-then-false.com/2012/php-apc-configuration-and-usage-tips-and-tricks
http://docs.moodle.org/22/en/Installing_APC_in_Windows