APC, which stands for Alternative PHP Cache, is a framework used for caching the compiled source code of a given script app, that can boost a database-driven site several times. Each time a PHP webpage is opened, the script pulls the website content that has to be loaded from a database, parses and compiles the program code, then the result is shown to the site visitor. While this is necessary for Internet sites with routinely changing content, it's a waste of processing time and system resources for a site that doesn't change, for instance an informational portal which shows the same content at all times. When the web pages for such a site are compiled, APC caches them and delivers them every time a user accesses them. As this saves the time to obtain content from the database and to parse and compile the program code, your Internet site will load considerably faster. APC is very useful especially for scripts with massive source code.
