Master boot record

A master boot record, or MBR, is like a map that tells your computer where to look to find the different parts it needs to start up. When you turn on your computer, it reads the MBR to figure out which program it needs to run first. This program is called the boot loader and it will then look for the operating system like Windows or Mac OS so it knows how to help you use your computer. The MBR is like the starting point on a map that your computer needs to find its way.