A distinct feature of the Erlang VM is the ability to trace and debug on a live system. In this tutorial we want to give people an overview of the facilities in the Erlang VM that helps a developer or administrator figure out errors in programs while they are running. The ability to operate on a live production system is a valuable trait of concurrent systems. Apart from Tracing and debugging, we will also be covering match specifications and we will introduce the "Restricted debugger" from the "eper" suite by Mats Cronqvist.

Erlang is perfectly suited for a modern distributed world. Part of this world is also a relatively new kind of client/server paradigm, namely Peer-to-Peer communication. We believe that this kind of communication is important to the modern internet and hence, the eTorrent project was born to gauge the usefulness of Erlang in a heavily distributed Peer-to-peer setting.

This talk is about using Erlang for implementing Peer-to-Peer clients. I claim Erlang made us write an efficient BitTorrent client in a fraction of the effort compared to other clients. I claim our client is more robust than the competition for normal operation. And I claim the Erlang mentality fits the Peer-to-Peer model well. I also explain how we utilize the Erlang platform to implement the client in an OTP-idiomatic way, and how we differ from the mainstream implementations.

Target audience: People with a keen interest in network protocols and Erlang.

Talk objectives: Explain how etorrent is designed and built.