Traditionally in CS, concurrent != parallel. If you have a blocking operation (say a database read) your program can do something else while it waits for a resp

Traditionally in CS, concurrent != parallel. If you have a blocking operation (say a database read) your program can do something else while it waits for a response from the DB (this gives you pseudo-parallelism). That is the concurrency that evented frameworks like Node or EventMachine are usually associated with.