Being very painfully pedantic (very precise in the use of terminology)… there is a difference between “concurrency” and “parallelism”. “Concurrency” involves the means the establishment of more than one independent process composed together to form a solution. You can create concurrent solutions and execute them on a system with a only a single CPU.
Parallelism refers to the ability to execute two or more concurrent processes simultaneously. You must have more than one processing core to execute two processes in parallel.
Erlang is built for concurrency and will run concurrent solutions (even with a single CPU). Given multiple execution cores, it can also execute processes in parallel.
