Concurrency in Go

Chapter 1. An Introduction to Concurrency

Concurrency is an interesting word because it means different things to different people in our field. In addition to “concurrency,” you may have heard the words, “asynchronous,” “parallel,” or “threaded” bandied about. Some people take these words to mean the same thing, and other people very specifically delineate between each of those words. If we’re to spend an entire book’s worth of time discussing concurrency, it would be beneficial to first spend some time discussing what we mean when we say “concurrency.”

We’ll spend some time on the philosophy of concurrency in Chapter 2, but for now let’s adopt a practical definition that will serve as the foundation of our understanding.

When most people use the word “concurrent,” they’re usually referring to a process that occurs simultaneously with one or more processes. It is also usually implied that all of these processes are making progress at about the same time. Under this definition, an easy way to think about this are people. You are currently reading this sentence while others in the world are simultaneously living their lives. They are existing concurrently to you.

Concurrency is a broad topic in computer science, and from this definition spring all kinds of topics: theory, approaches to modeling concurrency, correctness of logic, practical issues—even theoretical physics! We’ll touch on some of the ancillary topics throughout the book, but we’ll mostly stick to the practical issues ...