Performance Portability through Semi-explicit Placement in Distributed Erlang Dr Kenneth MacKenzie, University of St Andrews The Erlang language provides features which make it very easy to implement applications distributed over large networks. The problem then arises of how one should deploy such applications, particularly in networks where the individual nodes may have varying characteristics and where communication times may be non-uniform. In this talk, I'll describe some work from the RELEASE project at Glasgow where we designed and implemented libraries providing methods for "semi-explicit placement", where the programmer selects nodes for spawning remote processes based on properties of nodes and communication latencies. We claim that these methods will help programmers to achieve good performance in a portable way, without requiring detailed knowledge of the network in advance. I'll give an introduction to Erlang and the issues that arise in deploying distributed applications, and then describe our libraries, including some topological and statistical methods used in their design and validation. The Sao Tome shorttail and other birds will also put in an appearance.