What is concurrency?

Modern cars have become highly intricate machines that provide not only transportation but also various other functionalities. These functionalities include infotainment systems, which allow users to play music and videos, and heating and air conditioning systems, which regulate the temperature for passengers. Consider a scenario in which these features did not work simultaneously. In such a case, the driver would have to choose between driving the car, listening to music, or staying in a comfortable climate. This is not what we expect from a car, right? We expect all of these features to be available at the same time, enhancing our driving experience and providing a comfortable trip. To achieve this, these features must operate in parallel.

But do they really run in parallel, or do they just run concurrently? Is there any difference?

In computer systems, concurrency and parallelism are similar in certain ways, but they are not the same. Imagine you have...