The Core of an Operating System is the Kernel

At a low level, the “kernel” is the core computer program at the heart of your operating system. This single program is one of the first things loaded when your operating system starts up. It handles allocating memory, converting software functions to instructions for your computer’s CPU, and dealing with input and output from hardware devices.

The kernel is generally run in an isolated area to prevent it from being tampered with by other software on the computer. The operating system kernel is very important but is just one part of the operating system.

The lines here can be a little fuzzy, too. For example, Linux is just a kernel. However, Linux is still often called an operating system. Android is also called an operating system, and it’s built around the Linux kernel. Linux distributions like Ubuntu take the Linux kernel and add additional software around it. They’re referred to as operating systems, too.