When the computer system starts, the computer's BIOS locates and runs the bootstrap program on the MBR (Master Boot Record). A series of programs (of Grub) are run provide the user with a selection of operating system to boot. For example, the user can select a version of Linux to load the Linux Kernel, or the user can select another operating system (like Windows) to load in the boot-loader (eg. NTLDR). This process of loading boot loaders for other non-Linux operating systems is referred to as chainloading.

== Advantages of Dual / Multiple Boot ==