GRUB 2

GRUB 2 is a Multiboot boot loader. It's derived from GRUB (GRand Unified Bootloader), originally designed and developed by Erich Stefan Boleyn.

Shortly the boot loader is the first programm that starts when a PC starts. It loads the first stage of the operative system and give to it the control so that it can initialize all the system.

Configuration
The configuration of GRUB 2 in openmamba is possible editing the file

/etc/sysconfig/grub

which default content is: GRUB_OTHER_TITLES=("Windows 98") GRUB_OTHER_DEVICES=(/dev/hda3)
 * 1) grub2 configuration file
 * 2) Uncomment the following lines to configure other systems (chainloaded)
 * 3) to appear in grub2 boot menu.
 * 1) Uncomment the following lines to configure other systems (chainloaded)
 * 2) to appear in grub2 boot menu.
 * 1) to appear in grub2 boot menu.

h=silent,fadein console=tty1"
 * 1) Define an alternative command line for linux entries
 * 2) GRUB_CMDLINE_LINUX="resume2= video=uvesafb:1024x768-32,ywrap,mtrr:3 quiet splas
 * 1) GRUB_CMDLINE_LINUX="resume2= video=uvesafb:1024x768-32,ywrap,mtrr:3 quiet splas

GRUB_DEFAULT=1
 * 1) Define default menu entry

GRUB_TIMEOUT=1
 * 1) Define boot menu timeout before loading default menu entry


 * 1) Definitions for serial console
 * 2) GRUB_TERMINAL=
 * 3) GRUB_SERIAL_COMMAND=
 * 1) GRUB_SERIAL_COMMAND=


 * 1) Apply changes with:
 * 2) update-grub
 * 1) update-grub

The modify done to the file are applied running the following command:

/usr/sbin/update-grub

that create the true configuration file used by grub:

/boot/grub/grub.cfg

Note: It'is advised to not edit that file because it's rewrited at every kernel update. The correct way to apply the modify is to use the update-grub.

Booting a non Linux operative system
To configure the boot of a non Linux operative System (for example a Windows version), you must identify the partition in which the system is, as Linux know it, for example

/dev/hda1

is the firts partition of the first IDE hard disk. Now we can add the following lines to the configuration file '/etc/sysconfig/grub:

GRUB_OTHER_TITLES=("Windows 98") GRUB_OTHER_DEVICES=(/dev/hda1)

The following example shows the case in which there are more then one alternative system:

GRUB_OTHER_TITLES=("Windows 98" "FreeBSD") GRUB_OTHER_DEVICES=(/dev/hda1 /dev/hda4)

How to set the default boot system
Normally GRUB starts a default system if, after 5 seconds from the boot menu, the user don't touch any key. To set a default system other than the first (know as number 0) add (or uncomment) the following line in /etc/sysconfig/grub:

GRUB_DEFAULT=1

In that case the default boot system is the one in the second line of the boot menu.

How to change the timeout of the boot menu
To modify the boot menu timeout, set the following line in /etc/sysconfig/grub:

GRUB_TIMEOUT=30

That example set the timeout to 30 seconds.