Introducing concurrency

Concurrency simply means having multiple pieces of logic within a program being executed simultaneously. Modern software systems are often concurrent, as programs need to run various pieces of logic at the same time. As such, concurrency is something that every program today is using to a certain extent.

We can say that concurrency is a powerful tool that lets you write programs that can manage different tasks at the same time, and the support for it usually lies in the kernel, which is at the heart of the operating system.

There are numerous examples in which an ordinary program manages multiple jobs simultaneously. For example, you can surf the web while downloading files. In this case, tasks are being executed in the context of the browser process concurrently. Another notable example is in a video streaming scenario, such as when you are watching a video on YouTube. The video player might be in the middle of downloading future chunks...