PHP does not natively provide a way to create a true multi-threaded application. Yet, with the right combination of technologies it is possible to emulate multiple threads. If PHP is running inside of a web server, and has either read/write access to the file system or your application has access to a database then it is possible to open a socket, create a HTTP request which contacts itself and thus creates a segment in memory to run the new PHP task. The file system or database service as the IO for the thread to create a monitor or pass events back and forth to the new memory space.