Concurrency for Parallelism?

So, following up on the previous post, what is the difference between concurrent programming and parallel programming?

In my view, concurrent programming is concerned with coordination, whereas parallel programming is concerned with efficiency. In a way, you could say parallel programming is about avoiding coordination to the extent possible for the sake of performance. It seems reasonable to assume that concurrency and parallelism call for different tools.

Concurrent languages such as Go support parallelism basically out of the box: create a number of independent tasks and make sure they are scheduled by a pool of worker threads. Done in a few lines of code. Problem solved?

I agree that a single set of concurrency constructs is too limiting for the kind of parallel programs we’d want to write. Consider parallel loops, for example. Relatively straightforward to implement in Go, but starting a goroutine for each iteration? Hardly practical. This is not to say that goroutines and channels can’t be used to implement parallel loops efficiently; they can, it’s just more work. But programmers shouldn’t have to worry about goroutines and channels when all they want to do is run some iterations of a loop in parallel.