Grub 2 Basics

[ranch hand]

What I do not understand about this is that there seems to be this same problem (I think from what I read in the testing forum) in grub1.97.

Why not throw grub 1.97 onto 9.10 and fix it there? Grub 1.97 is a little nicer than grub1.97beta4 and I do not understand why the folks in charge os the Ubuntu grub program do not use it in 9.10. I know that it runs fine there as that is what I am using in my 9.10 installs.

I particularly like being able to use "grub-mkconfig" to pull up my grub.cfg file in the terminal to check things. This is quicker than going to the file or pulling it up in gedit.

[ranch hand]

I have been following the theming discussion in the testing forum and everyone seems to think that the /etc/grub.d/10_linux file is where all your Ubuntu installs are picked up.

This is not the case as far as I can tell. Here is the grub.cfg file from my 9.10 respin on my test platform. As can be seen there is only on non-Ubuntu install and all installs can be seen to be Linux;

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
set have_grubenv=true
load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
set saved_entry=${prev_saved_entry}
save_env saved_entry
set prev_saved_entry=
save_env prev_saved_entry
fi
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
if loadfont /usr/share/grub/unicode.pf2 ; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
if terminal_output gfxterm ; then true ; else
# For backward compatibility with versions of terminal.mod that don't
# understand terminal_output
terminal gfxterm
fi
fi
set locale_dir=/boot/grub/locale
set lang=en
insmod gettext
if [ ${recordfail} = 1 ]; then
set timeout=-1
else
set timeout=100
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
insmod png
if background_image /usr/share/images/desktop-base/menu.png ; then
set color_normal=black/black
set color_highlight=magenta/black
else
set menu_color_normal=white/black
set menu_color_highlight=black/white
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/09_custom ###
menuentry "Stoner1.2 on sda12" {
set root=(hd0,12)
linux /vmlinuz root=/dev/sda12 so quiet splash
initrd /initrd.img
}
menuentry "Lounge on sda7" {
set root=(hd0,7)
linux /vmlinuz root=/dev/sda7 so quiet splash
initrd /initrd.img
}
menuentry "Lxde on sda8" {
set root=(hd0,8)
linux /vmlinuz root=/dev/sda8 ro quiet splash
initrd /initrd.img
}
menuentry "Daily on sda13" {
set root=(hd0,13)
linux /vmlinuz root=/dev/sda13 so quiet splash
initrd /initrd.img
}
menuentry "ISO-test on sda14" {
set root=(hd0,14)
linux /vmlinuz root=/dev/sda14 ro quiet splash
initrd /initrd.img
}
menuentry "Mini on sda15" {
set root=(hd0,15)
linux /vmlinuz root=/dev/sda15 ro quiet splash
initrd /initrd.img
}
menuentry "Throw on sda16" {
set root=(hd0,16)
linux /vmlinuz root=/dev/sda16 ro quiet splash
initrd /initrd.img
}
menuentry "Krap on sda17" {
set root=(hd0,17)
linux /vmlinuz root=/dev/sda17 ro quiet splash
initrd /initrd.img
}
menuentry "Zenix on sda11" {
set root=(hd0,11)
linux /vmlinuz root=/dev/sda11 so quiet splash
initrd /initrd.img
}
menuentry "Main, kernel 2.6.24-24-generic (sda6)" {
set root=(hd0,6)
search --no-floppy --fs-uuid --set e2e3cd65-bc09-487f-be96-a83fcc282e38
linux /boot/vmlinuz-2.6.24-24-generic root=UUID=e2e3cd65-bc09-487f-be96-a83fcc282e38 ro quiet vga=773
initrd /boot/initrd.img-2.6.24-24-generic
}
menuentry "Mandriva on sda10" {
set root=(hd0,10)
linux /vmlinuz root=/dev/sda10 so quiet splash
initrd /initrd.img
}
menuentry "Man-Both on sda10" {
linux (hd0,10)/boot/vmlinuz
initrd (hd0,10)/boot/initrd.img
}
### END /etc/grub.d/09_custom ###

### BEGIN /etc/grub.d/10_linux ###
menuentry "Ubuntu, with Linux 2.6.31-17-generic" {
set recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
set quiet=1
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
linux /boot/vmlinuz-2.6.31-17-generic root=UUID=d938681d-2c8e-47f7-9d0b-2ff29c760489 ro quiet splash
initrd /boot/initrd.img-2.6.31-17-generic
}
menuentry "Ubuntu, with Linux 2.6.31-17-generic (recovery mode)" {
set recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
linux /boot/vmlinuz-2.6.31-17-generic root=UUID=d938681d-2c8e-47f7-9d0b-2ff29c760489 ro single
initrd /boot/initrd.img-2.6.31-17-generic
}
menuentry "Ubuntu, with Linux 2.6.31-16-generic" {
set recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
set quiet=1
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
linux /boot/vmlinuz-2.6.31-16-generic root=UUID=d938681d-2c8e-47f7-9d0b-2ff29c760489 ro quiet splash
initrd /boot/initrd.img-2.6.31-16-generic
}
menuentry "Ubuntu, with Linux 2.6.31-16-generic (recovery mode)" {
set recordfail=1
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
insmod ext2
set root=(hd0,12)
search --no-floppy --fs-uuid --set d938681d-2c8e-47f7-9d0b-2ff29c760489
linux /boot/vmlinuz-2.6.31-16-generic root=UUID=d938681d-2c8e-47f7-9d0b-2ff29c760489 ro single
initrd /boot/initrd.img-2.6.31-16-generic
}
### END /etc/grub.d/10_linux ###

As you can see the only thing that 10_linux is picking up is the entries for partition sda12 which is StonerEdition1.2, the OS generating this grub.cfg. All scripts past 10_linux have been disabled.

Is this right? It is the way of all my many installs, both on my test platform and on my main drives with stable releases.

Does 30_os-prober read something from 10_linux in doing its thing for identifying OS'?

[drs305]

10_linux only picks up linux versions on the default partition. 30_os-prober will find linux kernels on other partitions. If you look at the script in 30_os-prober there are sections for windows (OS), Linux (linux) and OSX.

I have been told that 1.97beta4 will not be upgraded to 1.97 in Karmic, in keeping with the 'stable release' philosophy. I've also been told there are no huge improvements. I do know the GRUB devs are working very hard to improve GRUB 2. I asked if 1.98 would make it into the Lucid LTS and they are not sure.

[zika]

It seems I'm either having problems with grub-mkconfig or lacking patience. I start it with {sudo,gksu} grub-mkconfig and nothing happens for ages. I know, update-grub takes for ages also, but is it something wrong or am I inpatient?

[ranch hand]

OK, I thought maybe I was nuts. Well I probably am anyway.

I suspect that the impression I got was from reading posts from folks that have enough brains not to have lots of installs or at least just one of each type of OS (Linux, Mac, MS).

Thanks for clearing that up for me.

For those wondering, yes there are 2 entries in my menu for Mandriva 2009-1. I need to get rid of the first one "Mandriva" and just leave the "Man-both" entry. The Mandriva entry does not work, it was put in to see if it would. I knew the Man-both would work so it was put in too.

[drs305]

It seems I'm either having problems with grub-mkconfig or lacking patience. I start it with {sudo,gksu} grub-mkconfig and nothing happens for ages. I know, update-grub takes for ages also, but is it something wrong or am I inpatient?

On my machine, update-grub takes about 20 seconds. It searches all your partitions. You can speed it up by disabling scripts in /etc/grub.d/ that you don't need run, such as 30_os-prober if you don't have systems on other partitions or already have them in a custom file.

[ranch hand]

It seems I'm either having problems with grub-mkconfig or lacking patience. I start it with {sudo,gksu} grub-mkconfig and nothing happens for ages. I know, update-grub takes for ages also, but is it something wrong or am I inpatient?

It does take a while to come up. It basically is checking the entire thing before displaying it so it takes about the same time as "update-grub".

[ranch hand]

On my machine, update-grub takes about 20 seconds. It searches all your partitions. You can speed it up by disabling scripts in /etc/grub.d/ that you don't need run, such as 30_os-prober if you don't have systems on other partitions or already have them in a custom file.

Good point.

I assume everyone has a custom file of some kind. It just is too easy to maintain. I love it. I do leave the 10_linux file enabled on the test drive in case I need it for some reason. Haven't needed it yet so it may be going soon.

[zika]

It does take a while to come up. It basically is checking the entire thing before displaying it so it takes about the same time as "update-grub".

Thanks. So, as I suspected, it is, just, my impatience...
I'll stick with nano and editing those two files, it's much faster...

[ranch hand]

According to the grub project folks "grub-mkconfig" was supposed to take the place of "update-grub" in 1.97. I haven't checked recently so I do not know if they changed the plan or if the Ubuntu folks decided to have it work this way.