On Friday 14 March 2008 07:15 pm, Agnello George wrote:
now suppose i have Two OS install -- debian Etch and the centos ...and grub is the default boot loader ( and grub file is located in /etc/grub.conf ..which has instruction / menu screen for booting the various OS ) but i don't seem to understand one thing - How is /etc/grub.conf made available to the boot loader even before a OS is selected ( explanation not very clear in the article )
Grub is almost an os with a shell and fs reader. once stage2 is loaded it can recognise partitions and most filesystems.
-- Regards Agnello Dsouza www.linux-vashi.blogspot.com
On 3/14/08, jtd jtd@mtnl.net.in wrote:
On Friday 14 March 2008 07:15 pm, Agnello George wrote:
now suppose i have Two OS install -- debian Etch and the centos ...and grub is the default boot loader ( and grub file is located in /etc/grub.conf ..which has instruction / menu screen for booting the various OS ) but i don't seem to understand one thing - How is /etc/grub.conf made available to the boot loader even before a OS is selected ( explanation not very clear in the article )
Grub is almost an os with a shell and fs reader. once stage2 is loaded it can recognise partitions and most filesystems.
So let me guess when we install linux we have the follow in the partition table
in hd0 we have / /boot swap
and hd1 we have / /boot swap
and in hd0 we have the grub.conf file located in /boot/grub/grub.conf
and in hd1 we have the grub.conf file located in /boot/grub/grub.conf
so ultimately which conf file is read ??
Agnello George wrote:
On 3/14/08, jtd jtd@mtnl.net.in wrote:
On Friday 14 March 2008 07:15 pm, Agnello George wrote:
now suppose i have Two OS install -- debian Etch and the centos ...and grub is the default boot loader ( and grub file is located in /etc/grub.conf ..which has instruction / menu screen for booting the various OS ) but i don't seem to understand one thing - How is /etc/grub.conf made available to the boot loader even before a OS is selected ( explanation not very clear in the article )
Grub is almost an os with a shell and fs reader. once stage2 is loaded it can recognise partitions and most filesystems.
So let me guess when we install linux we have the follow in the partition table
in hd0 we have / /boot swap
and hd1 we have / /boot swap
and in hd0 we have the grub.conf file located in /boot/grub/grub.conf
and in hd1 we have the grub.conf file located in /boot/grub/grub.conf
so ultimately which conf file is read ??
There may be 10 different linux partitions with grub and conf files each. It is up to you to set which partition is the root for grub. This is done automatically by the last OS that is installed or manually by re-installing grub with custom preference.
On Fri, Mar 14, 2008 at 10:26 PM, Agnello George agnello.dsouza@gmail.com wrote:
So let me guess when we install linux we have the follow in the partition table
in hd0 we have / /boot swap
and hd1 we have / /boot swap
and in hd0 we have the grub.conf file located in /boot/grub/grub.conf
and in hd1 we have the grub.conf file located in /boot/grub/grub.conf
so ultimately which conf file is read ??
To install grub, if you do a grub-install /dev/hda, the file in /dev/hda is read.
While installing a second distro for multibooting, you will be asked if you need to install a fresh copy of grub, if you say yes, it will be re-installed in the MBR and will point to the grub.conf of that distro's /boot partition. This is sufficient only to get the initial grub boot menu screen. After that what kernel to boot is taken from the root and kernel parameters of grub.conf.
BTW, when you do a df -k after booting to any one distro of your multiboot system, have you ever seen two /boot, two / and two swap partitions?
Regards, NMK.
On 3/14/08, Agnello George agnello.dsouza@gmail.com wrote:
in hd0 we have / /boot swap
and hd1 we have / /boot swap
and in hd0 we have the grub.conf file located in /boot/grub/grub.conf
and in hd1 we have the grub.conf file located in /boot/grub/grub.conf
so ultimately which conf file is read ??
The one installed on MBR of the first bootable drive.
-
Agnello George -
jtd -
Mehul Ved -
Nadeem M. Khan -
Rony