Grub issues + not entirely sure of bios boot order sequence

dime2000 · n00b Joined: 28 Jan 2006 Posts: 2

Hi all, so far i seem to be able to make it all the way through install until i have to write my own grub script -

Here goes....
I have 4 sata disks on my system. Fdisk says Windows is on sdc1 and i am installing on sdd - not sure firstly why it's not sda for windows since it's connected to the first sata point on my motherboard (A8N-SLI). Suppose it doesn't matter. My motherboard is set to boot my sdc drive first, and then sdd.

Here's what i wrote for my grub.conf

default 0
timeout 30
splashimage=(hd3,0) /boot/grub/splash.xpm.gz

title=Gentoo Linux 2.6.15
root (hd3,0)
kernel /boot/kernel-2.6 root=/dev/sdd3

title=Windows XP
rootnoverify (hd2,0)
makeactive
chainloader +1

I then ran #grep -v rootfs /proc/mounts > /etc/mtab
_________#grub-install /dev/sdd <=Is this right? I imagine the grub script would put the chainloader into windows boot using this.

Then when i reboot with current boot order pref windows boots as normal with no grub load. If i change the boot pref order, then the grub does load but only to a black screen which counts to 30. And this is where i'm really confused? Any suggestions would be really appreciated as i really want to try out gentoo.

Plus, i also wanted to point out then when i go into into the grub command line and press tab with various directories to reference from, the tab function doesn't work but just creates a tabbed space. Any ideas? It's really odd and also hence why i am discussing my /dev/ locations using fdisk.

I've tried looking through various posts and reading around a bit but nothing's really clicked - when i perform install it never says there's any errors; probably means my script is way off :cry:

Cheers to all in advance

Jaglover · Posted: Sat Jan 28, 2006 9:43 pm Post subject:

Once upon time the only disk order in a computer was the physical order. The very first HDD was the only one to boot from. Period. One could have more operating systems on other disks, but the MBR and boot loader on first HDD was a must.
Nowadays there is a clever option in the BIOS - boot drive setting. So what do you think how this is done? Simple - BIOS swaps the drives and lies about physical order. Now, if OS relies on BIOS information it thinks your third drive is first physical drive. All utilities and operating systems what do not use BIOS think otherwise.
In other words - let BIOS to fake your drive order and you are asking for trouble.

widan

dime2000 · n00b Joined: 28 Jan 2006 Posts: 2

Hey thanks for your help though i still can't seem to fathom all this,

i checked my BIOS and it reads port one as my windows C hard drive, port 2 as the linux one and the other two as 3 and 4 respectively - does this mean they're numbered correctly? And further my boot order in BIOS corresponds to this exact sequence.

I then looked in windows and it said that my windows harddisk is on Location 0 (secondary ATA channel) and linux on Location 0 (primary channel). Urggh!

Then loaded grub - again the TAB functions not working - and probed it with root and it still says that gentoo is on hd3 and windows on hd2. So i added this stuff to my conf file so the end now reads

title=Windows XP
rootnoverify (hd2,0)
map (hd2) (hd0)
map (hd0) (hd2)
makeactive
chainloader +1

and then exec #grub-install /dev/sdd <-is this right?

And yes it didn't work. when you say i should try (hd0,0) do you mean to consider Windows to be on this /dev/hd0 but leave the rest of the dev paths the same or should i change their paths to correspond as well by knocking off 3 to their part scheme?

cheers

Jaglover · Posted: Sun Jan 29, 2006 8:08 pm Post subject:

Look. Whatever disk is set to boot in BIOS is going to be hd0 for GRUB. And this is also the disk where to install GRUB.