What is a Boot Loader and How Does it Work?

Probably at least eight out of ten people have never installed an operating system in a computer before, so it really wasn't until Apple released something called "Boot Camp" that the concept of a "boot loader" even entered the technology marketplace for most people.

A boot loader is a very simple piece of software that mediates between computer firmware: the largely permanent instructions that tell a computer what hardware is installed in it, and computer software, which is usually an operating system.

Every disk has a small part of it set aside called the "boot sector." When a computer is turned on, the firmware looks for a "bootable" disk, or a disk with a boot sector that has something written on it. That "something" is called a "boot loader" and what it does is load enough operating system instructions so the operating system can start up correctly.

Boot loaders have become more popular recently because the new Intel-based Mac computers are capable of running nearly any current commercial operating system, including Windows.