Erlang's concurrency model has been used in commercial systems for well over 15 years, but what differentiates it from other technologies? What are the constructs, what makes them so powerful and scalable, and when using them, what change in mindset is required from the developers? What makes Erlang an excellent choice when developing with SMP in mind?

This talk, based on 15 years of concurrent functional programming in Erlang, attempts to answer all these questions. It covers the constructs which provide the concurrency model and the fault tolerance built around it.

With live demos, we will be providing benchmarks on process creation and message passing. We will give practical examples of IM and SMS based systems which make the correct use of the concurrency model, providing case studies of systems that work, and ones that don't.

The talk will conclude with our experiences of using Erlang on multi-processor machines, and the challenges this boost in performance is giving our developers.