ErlangTW is a parallel/distributed simulation middleware based on the Time Warp synchronization protocol. ErlangTW is entirely written in Erlang, a concurrent, functional programming language specifically targeted at building distributed systems. We argue that writing parallel simulation models in Erlang is considerably easier than using conventional programming languages. Moreover, ErlangTW allows simulation models to be executed either on single-core, multicore and distributed computing architectures. We have developed a complete implementation of Time Warp and to evaluate the performance of ErlangTW we used a synthetic benchmark called PHOLD, that is a model specifically designed for the performance evaluation of Time Warp impleme...