GRUB2 is the next generation of the GRand Unified Bootloader (GRUB). Ubuntu has used GRUB2 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 GRUB2
- Questions on how GRUB2 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 GRUB2:
GRUB 2's major improvements over the original GRUB include:
- Scripting support including conditional statements and functions
- Dynamic module loading
- Rescue mode
- Custom Menus
- Graphical boot menu support and improved splash capability
- Boot LiveCD ISO images directly from hard drive
- New configuration file structure
- Non-x86 platform support (such as PowerPC)
- Universal support for UUIDs (not just Ubuntu)