[zamalek]

> For example, running ten programs at once with only a single CPU. Concurrency is effectively CPU scheduling with maybe some other concepts of communication between processes for coordination.

This is called preemptive multitasking. This is like declaring that "sorting a list is quicksort." This can realize concurrency.

The reason that this is important is that cooperative multitasking (async/cps/fibers/safe points) is also concurrency. And I'm sure there are other exotic forms of concurrency that I'm not aware of beyond multitasking.

Concurrency is a property of a program/system, not a mechanism.