Multi booting is the act of installing multiple operating systems on a single computer, allowing the user to choose which OS to boot into at startup. This can be useful for a variety of reasons, such as running different software that is only compatible with certain OSes, testing different OSes, or having a backup OS in case the primary OS fails.
There are a few different ways to multi boot, but the most common is to use a boot loader. A boot loader is a small program that is installed on the computer’s hard drive and is responsible for loading the operating system into memory. When the computer starts up, the boot loader will display a list of the available operating systems and allow the user to choose which one to boot into.