Debian Packages: grub

Grub (the GRand Unified Bootloader) is a boot loader designed to address the limitations of lilo. It makes up for numerous deficiencies in many PC BIOSs while providing full-featured command line and graphical interfaces. Grub recognises fdisk partitions, can dynamically read Linux ext2fs, and MSDOS FAT16 and FAT32 filesystems, and can boot multiboot-compliant kernels (such as GNU Mach), as well as standard Linux and MSWindows kernels.

A good introduction to grub is available from http://www.gnu.org/software/grub/grub.html and a good guide to multi-boot setup is http://www.tldp.org/HOWTO/Multiboot-with-GRUB.html. This latter resource looks at multi-booting four operating systems although the information is still useful if all you want is to multiboot just two.

To switch from lilo to grub simply install it with:

# wajig install grub # grub-install /dev/hda # update-grub

This creates a /boot/grub/menu.lst file which you might like to review just to make sure it looks okay. For most simple situations it should be fine.

For a dual boot with MSWindows/NT on the first partition and Linux on the second (like Mint), you may need to change the default locations of Linux. Look at /boot/grub/menu.lst to see if the following two lines have been changed:

# kopt=root=/dev/hda1 ro # groot=(hd0,0)

to

# kopt=root=/dev/hda2 ro
# groot=(hd0,1)

Also, add to the end of the file:

title           Windows NT
rootnoverify    (hd0,0)
makeactive
chainloader     +1

Once it looks okay, run update-grub then reboot!

When installing new kernels you can have the new kernel automatically added to the menu by adding the following lines to /etc/kernel-img.conf (and in fact making the file look the same as) :

# Turn off Lilo stuff do_symlinks = no do_bootloader = no # Initrds are OK for GRUB do_initrd = yes # Run cool GRUB stuff postinst_hook = /sbin/update-grub postrm_hook = /sbin/update-grub

If you start having problems booting, at the grub menu type c to get the command line. Try:

root (hd0,4) (/dev/hda5) kernel /boot/vmlinuz-2.4.18-bf2.4 root=/dev/hda5 ro boot

More information on using grub is available from the Linux Journal.