The Boot process

Booting on a PC POST –Hardware test – may not run CPU ie fan not working CPU start-up –Jumps to fixed location to execute BIOS code BIOS –Initialises hardware –allows user interaction Bootloader –Allows selection of OS and parameters

Booting with GRUB Grand Unified Bootloader Part of the GNU development Currently changing from GRUB1 to GRUB2 Currently seen as the replacement for LILO

GRUB 3 stage booting process –Stages 1, 1.5 & 2 GRUB can be file system aware –Can ignore that stage Can run GRUB from the OS (LINUX) MBR resident code Linux resident Kernel Stage 1 Stage 1.5 Stage 2 File system Aware code

Why use GRUB? Although LILO works and has a huge Linux user base, many are changing to GRUB –More robust Does use maps which can easily change –Lower maintenance Don’t need to run lilo/silo –Easier maintenance Can run from OS –More features/command line options Bash style shell