April 21, 2019

Grub2 Worms Into Ubuntu (part 1)

Why Switch, GRUB2 Structure

  • February 11, 2010
  • By Akkana Peck

Part I: Configuration Overview

Grub, n.

  1. an informal term for a meal
  2. a soft thick wormlike larva of certain beetles and other insects
  3. GRand Unified Bootloader

figure 1
figure 1

What is Grub2?

Grub -- the GRand Unified Bootloader -- is the program in charge of booting your computer. When you start up your computer and get a menu asking you whether you want Windows or Linux -- that's grub.

Most of the time it just does its job quietly. But a change is coming: Ubuntu has switched to a new version called grub2 starting with the current 9.10 "Karmic koala" release, and other distros may eventually follow suit.

Why the Switch?

Reading the grub2 project's website, it's hard not to conclude that grub2 exists mainly because everybody was tired of hacking on the old grub1 code, and decided it would be more fun to write a new toy from scratch.

But to give people a reason to switch, they did add some new features:

  • Scripting
  • Better graphics support
  • Internationalization
  • Rescue mode
  • Better support for non-PC architectures, like Macs

This seems to have won the Ubuntu folks over. Most other distros are more cautious, and have not yet seen a reason to switch. So for now, grub2 is really only an issue for Ubuntu users.

Getting Grub2 ... or Avoiding It

If you install Ubuntu 9.10 from a CD, the installer will replace your current "legacy" grub with grub2.

However, it won't duplicate what was in your existing grub configuration. So if you've customized your boot menu, you'll have some work to do. Fortunately, grub2 won't remove the old files, so you'll still have the information you need to restore that menu.

If you're not quite ready to deal with that, fear not: the switch isn't mandatory yet. You have two options:

  1. Upgrading in place from an earlier Ubuntu version will not replace grub.
  2. From the LiveCD install, look for the "Ready to install" screen just after disk partitioning. Click on Advanced, then deselect "Install boot loader" (Figure 1). You'll have to update menu.lst once the install is finished.

But let's assume you did install grub2. How do you configure it?

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