GRUB 2 is the next generation of the GRand Unified Bootloader (GRUB). Ubuntu has used GRUB 2 as the boot loader since 9.10 (Karmic Koala). Commonly referred to as simply "GRUB".

What questions should have this tag?:

  • Questions on how to edit, repair, or troubleshoot GRUB 2
  • Questions on how GRUB 2 works

Some basic definitions:

Bootloader - This is a program which loads the operating system (OS) or other software, after POST (power-on self-test).

Boot Record - Contains information on which OS(s)/program(s) to "boot", and information about where these are located.

Brief introduction to the subject:

From the Ubuntu Wiki page for GRUB 2:

GRUB 2's major improvements over the original GRUB include:

  • Scripting support including conditional statements and functions
  • Dynamic module loading
  • Rescue mode
  • Custom Menus
  • Themes
  • Graphical boot menu support and improved splash capability
  • Boot live CD ISO images directly from hard drive
  • New configuration file structure
  • Non-x86 platform support (such as PowerPC)
  • Universal support for UUIDs (not just Ubuntu)

Important links for learning more: