From DeveloperWorks, WebSphere Process Server operational architecture: Part 1: Base architecture and infrastructure components

Part 1 of this two-part article series dives deeply into the operational
architecture of IBM WebSphere Process Server. This article introduces you to concepts, such as Service Component Architecture (SCA), Business Process
Choreographer (BPC) and Service Integration Bus (SIB) in the context of WebSphere
Process Server, and shows you how they work together to build a secure
transactional runtime environment for your SOA. In this respect, you will be able to
better articulate the technical architecture of WebSphere Process Server, which will
improve your ability to operate WebSphere Process Server in your organization..

Theres always a desire to understand the architecture and implementation of complicated software that makes your life ‘easier’. This is a great article that delves into the layers that compose Process Server and WebSphere Integration Developer.