APC
PHP Manual

Introduction

The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.

Warning

This extension is considered unmaintained and dead. However, the source code for this extension is still available within PECL GIT here: http://git.php.net/?p=pecl/caching/apc.git.

Note:

Alternatives to this extension are OPcache, APCu, Windows Cache for PHP and the Session Upload Progress API.