With the theory heavy portion of the series out of the way, we can begin to explore the various implementation possibilities. In this part, we will examine implementing Asynchronous Processing using a child process, i.e. a separate PHP process we create from our application during a request. We'll analyse this implementation option before introducing the source code so we may understand its advantages and disadvantages.

He looks at both the advantages and disadvantages of processing with child processes and suggests a method to get a handle on the processes rather than just spawning new processes - forking. Some basic code examples are included, using the popen function to open the new child process and a Zend Framework example.