How System Calls Work in Linux @ OSWeekly.com

A guide to some fundamentals of a Linux-based OS.

Every GNU/Linux programmer here reading this article must have
used system calls to code their programs. GNU/Linux programming is
incomplete without system calls. System calls are initiated by software
interrupts. Before we delve into that, however, let’s define system
calls. A system call is the mechanism used by an application program to
request service from the operating system, or more specifically, the
operating system kernel.

Source: OS Weekly