ITJungle.com has posted another article in their series looking at PHP on IBM's i5/OS platform that's already included an overview of System i and a very basic look at PHP's structure.
This article provides an overview of the API toolkit, and a collection of Application Programming Interfaces (APIs) that facilitate PHP programs accessing and working with i5/OS objects.
The article comes complete with diagrams of the stacks for both LAMP and iADP as well as an overview of the Zend Core API and a code example of how to make a connection to the backend and send off a message (SNDMSG) to the local system.