Understanding the Difference Between Concurrency and Parallelism

Concurrency refers to managing multiple tasks that can overlap, whereas parallelism specifically refers to tasks executing simultaneously. Some folks dive deeper into the differences, but the main thing is understanding that concurrency can happen even without parallelism, as long as the tasks have the potential to interfere with one another.

At its core, concurrency is about managing tasks that can overlap in time, while parallelism is about executing multiple tasks at once. So yes, the tasks running on different cores at the same time would typically be described as parallelism, not just concurrency.

Absolutely, it's fair to view parallelism as a way to achieve concurrency, or even a subset of it. Parallelism involves tasks literally running at the same time, while concurrency is more about overlapping execution that allows multiple tasks to make progress, whether that's through context switching on a single core or parallel execution on multiple cores.

Parallelism essentially involves dividing work into chunks that can run independently. For instance, if you have three tasks and three processors, they can run simultaneously, drastically reducing the time taken. Concurrency is more about switching between tasks, like how an operating system can make it seem like two tasks are happening at once, even if they are just context switching on a single processor.

You're on the right track with your understanding! Think of concurrency as being about structuring a program so that it can handle multiple tasks making progress at the same time. Parallelism, on the other hand, is all about executing those tasks simultaneously using different hardware resources. So yes, you can have concurrency without parallelism, but a parallel program is specifically concurrent since multiple flows are happening at once.