Processes and threads
Throughout this book, we are mainly interested in task scheduling within computer systems. In an operating system, tasks are either processes or threads. We'll explain them and their differences in the upcoming chapters, but for now, you should know that most operating systems treat both in basically the same way: as some tasks that need to be executed concurrently.
An operating system needs to use a task scheduler to share the CPU cores among the many tasks, be they processes or threads, that are willing to use the CPU for their execution. When a new process or a new thread is created, it enters the scheduler queue as a new task, and it waits to obtain a CPU core before it starts running.
In cases in which a time-sharing or preemptive scheduler is in place, if the task cannot finish its logic in a certain amount of time, then the CPU core will be taken back forcefully by the task scheduler and the task enters the queue again, just like in...
