Enter PHP 4

The PHP 3 engine, although extremely popular and sufficiently fast, was starting to suffer from growing pains as more and more people used it for increasingly complex applications. Therefore, the creators of the PHP 3 engine, Zeev Suraski and Andi Gutmans, decided that a complete rewrite was due.

The result of that rewrite is the Zend engine (named after Zeev and Andi). The Zend engine is the core of PHP 4, which offers greatly improved performance and a host of new features. It expands PHP's viability, making it an excellent tool for complex Web applications as well as small-to-medium size Web sites.