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.
Contents
Configuration
The configuration of GRUB 2 in openmamba is possible editing the file
/etc/sysconfig/grub
which default content is:
# # grub2 configuration file # # # Uncomment the following lines to configure other systems (chainloaded) # to appear in grub2 boot menu. # GRUB_OTHER_TITLES=("Windows 98") GRUB_OTHER_DEVICES=(/dev/hda3) # Define an alternative command line for linux entries # #GRUB_CMDLINE_LINUX="resume2= video=uvesafb:1024x768-32,ywrap,mtrr:3 quiet splas h=silent,fadein console=tty1" # Define default menu entry # GRUB_DEFAULT=1 # Define boot menu timeout before loading default menu entry # GRUB_TIMEOUT=1 # Definitions for serial console # #GRUB_TERMINAL= #GRUB_SERIAL_COMMAND= #Apply changes with: # # 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.
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.