Before Red Hat Linux can run, it must be loaded into memory by a special program called a boot loader. A boot loader usually exists on the system's primary hard drive (or other media device) and has the sole responsibility of loading the Linux kernel with its required files or (in some cases) other operating systems into memory.
Each architecture capable of running Red Hat Linux uses a different boot loader. For example, the Alpha architecture uses the aboot boot loader, while the Itanium architecture uses the ELILO boot loader.
This chapter discusses commands and configuration options for the two boot loaders supplied with Red Hat Linux for the x86 architecture: GRUB and LILO.