1. GRUB 2
Dave Soergel

2. GRUB – GRand Unified Bootloader
Latest version is GRUB 2
Still under development!
Original version now known as GRUB Legacy
New Features
Supports even more OSs and platforms..
More modular design
Better UUID support
Boot live CD .iso files
Scripting for menu generation
Menu password support
Allows splasher menus

3. GRUB Boot Sequence (Hard Disk)
boot.img
Installed in MBR
Loads and starts first block of core.img
core.img
Installed in space after MBR
Minimal image
Understands the file system
Includes GRUB kernel and required device specific modules
Installs other modules from file system as required
Processes grub.cfg

4. GRUB Changes Partition numbers now start at 1 (hd0,3) → /dev/sda3
GRUB Command line
Available at boot time only
No interactive command line from running system

5. GRUB 2 Key Runtime Files /boot/grub/grub.cfg
Generates the menu (replaces menu.lst)
Generated by grub-mkconfig or update-grub
Manual edits lost after each update
/boot/grub/device.map
Maps GRUB device names to system device names
Generated at initial install time
Can be edited if required

6. GRUB 2 Key Configuration Files
/etc/grub.d/##_...
Shell scripts to generate grub.cfg
## is 2 digit number indicating order of script execution (10_linux)
/etc/default/grub
Default and operational parameters
Used by scripts to generate grub.cfg
Meant to be edited

7. Installing GRUB Installation on system
Install package or build from sources
Installation on device
grub-install device
Installed in /boot/grub
Images installed to device as required