> "Typically these are brittle C/C++ programs, with lots of state and branching logic, and further they become extremely hard to refactor because their function

> "Typically these are brittle C/C++ programs, with lots of state and branching logic, and further they become extremely hard to refactor because their function is so integral to running the facility" Switching to Erlang won't inherently make those issues disappear. Erlang could definitely save you some C/C++ boilerplate code, but if your business logic is still stateful, it's not necessarily going to be easier to implement any of that with Erlang. Erlang is probably more forgiving on the developers than C/C++ are, but that can be said of many other languages (ie. Python, Java). If you're looking to pass messages around between processes/threads, there are plenty of libraries you can use today to start refactoring that C/C++ code: http://nanomsg.org/ http://nanomsg.org/ http://zeromq.org/ http://zeromq.org/ https://www.rabbitmq.com/ https://www.rabbitmq.com/ (most likely an overkill for the specific use-case you described, will be more relevant in a distributed computing scenario)