Unbeknownst to most users, computer operating systems have a core section that loads before everything else. Known as a kernel, it plays a fundamental role in nearly all operating systems, including Windows. When you boot up your computer, the kernel will load first. Only after loading the kernel will you see the icons and files associated with the operating system.

What Is a Kernel?

A kernel is native program in operating systems that provides functionality for all other aspects of the respective operating system. Among other things, it manages Central Processing Unit (CPU) time, random access memory (RAM) usage and device or peripheral connections.

Regardless of what operating system your computer uses, it probably has a kernel. As previously mentioned, the kernel loads first — and it continues to run until the computer is turned off. The kernel runs in your computer’s RAM where it provides instructions to your computer on how to perform various tasks, specifically the interactions between hardware and software.

Why Operating Systems Use Kernels

Kernels serve several purposes, one of which is to maximize performance. Without a kernel, programs may consume an excessive amount of CPU time or RAM. As a result, you may encounter lag or other performance problems. A kernel helps to maximize performance by dictating the way in which your computer uses CPU and RAM resources.

In addition to maximizing performance, kernels also protect hardware from damage caused by malware or other cyber threats. Some types of cyber threats are designed to harm or destroy computer hardware components. A virus, for example, may consume your computer’s RAM to the point where it overheats. Kernels protect against hardware damage such as this by placing restrictions on how much RAM — or other resources — programs can use.

Kernel vs BIOS: What’s the Difference?

It’s important to note that a kernel isn’t the same as a Basic Input-Output System (BIOS). A BIOS is a type of program that runs before the operating system. It’s coded directly into a computer’s motherboard where it loads the OS.

The BIOS tells your computer to load the OS. The purpose of the BIOS is to provide a failsafe in case the OS stops working. If your computer’s OS becomes corrupted or otherwise fails to load, you should still be able to access the BIOS. From the BIOS, you can then attempt to either troubleshoot the OS or delete and install a new OS.