Before we start

In this article there isn't a single line of code and it's not aimed at teaching the intricacies of multithreaded programming in any given programming language but to give a short introduction, focusing primarily on how and especially why and when multithreaded programming will be useful.

So, what is multithreaded programming?

Nowadays all operating systems (except maybe the educational ones) are multitasking operating systems. This means they can run multiple tasks or processes at the same time. This has not always been so, the ms-dos was a monotasking system which means that only one task could run on the system simultaneously.

Before rushing to explain multithreaded programming is desirable to review certain features common to operating systems.

Multitasking and multiprocessing. The Scheduler.

When we talk about multitasking operating systems we say they can run multiple tasks simultaneously in parallel. This is not entirely true, just multiprocessor systems (with more than one processor) can make real multitasking, in a system with one processor we talk about the illusion of multitasking.