Boot Loader

The Boot Loader is just a program that knows, either by searching the hard disks for bootable partitions or by some config file, where Operating Systems are installed on the machine. Usually the Boot Loader will present you with options to boot all of the various operating systems on your machine. When the selection of OS is chosen, the Boot Loader will load the OS. This can be done in a couple of different ways. We will talk about GRUB, the GRand Unified Bootloader, since that is the one we have suggested to use in the previous meetings. Loading the Window$ kernel with GRUB employs a technique known as chainloading. This means that GRUB loads the boot sector from the partition that Window$ is located on and executes the code found there. This code knows how to find the Window$ kernel so it loads and executes it. When loading the Linux kernel, GRUB can take advantage of it's knowledge of filesystems to load the selected Linux kernel directly from within the filesystem that Linux resides on. This takes us the the Kernel boot process.