BEAM, the virtual machine for Erlang, was built by Ericsson to handle internet traffic. Today Erlang is used in many high volume settings like gaming, messaging and financial services. For example, WhatsApp uses Erlang to handle close to a 100 billion messages per day.

The language and the machine was designed from the ground up to be robust, maintainable, and scalable.

In this talk we will look at the BEAM in detail to see how it is implemented. We will look at the motivation behind the Erlang design and how it has affected the virtual machine. We will look closely at how the most central concepts, processes and concurrency, are implemented. We will also look at memory management, instruction dispatching, and some pragmatic optimizations.