Dual Boot on Two Drives

EDIT:This thread is now largely irrelevant, as 7.04 has an "Advanced" button at the Grub installation stage, which when pressed gives the option to enter a different location for Grub to be written to.

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Generally in Ubuntu EDIT: up to6.10? the usual way to install a dual-boot system involves overwriting the Master Boot Record of the Windows hard drive.

On one hard drive this is pretty much unavoidable.

However,

If you are dual-booting with TWO hard drives it is not necessary to write Grub over the MBR if you can access a "Boot Device Selection Menu" by pressing F8
(or whatever key depending on BIOS)

You can thus keep both installations entirely separate.

To do it this way:

Disconnect the Windows drive and install Ubuntu and Grub on the second drive. Reconnect first drive after installing Ubuntu.

Windows on master, Ubuntu & Grub on slave if using two IDE drives.

(This method will also work on SATA drives, or a mix of SATA & IDE)

Press F8 (or whatever key depending on BIOS version) at boot time to bring up the Boot Device Selection Menu.

Choose OS by selecting which drive to boot from.

Select desired default OS by re-arranging boot order in BIOS.

Only need to press F8 to select non-default OS.

Re-boots are as quick as using traditional Grub-in-MBR option.

Always disconnect other OS's drive if re-installing.

This process will also work for adding Windows to an Ubuntu system

Access to files on either drive can be configured later on, once you've got a safe installation organised.


Edit: The following information will allow dual-booting on two drives with all BIOS versions, with a little editing of Grub. Thanks are due to Anaconda and Bulldog


Yep all good and so, but..

it would be even better if the hd with ubuntu is the master and windows hd is the slave.

Everything would work just like in your example (no grub in windows drives mbr), but you wouldn't have to do anything in the bios, and in all bios:s it propably even isn't possible to select the booting drive..

But if you have ubuntu in master, then when you boot you would go to grub, and you can select which os is booted. The only thing you would have to do is edit /boot/grub/menu.lst and add windows to your grub..

title Windows NT/2000/XP (loader)
map (hd0,0) (hd1,0)
map (hd1,0) (hd0,0)
rootnoverify (hd1,0)
makeactive
chainloader +1

remapping hd:s when booting to windows from slave drive is nesessary, because windows wants to think it is in the master drive..

and if you remove either hd from your machine, the other one would work normally like in your example...
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anaconda

gn2: The end result is the same, Grub is kept off the Windows MBR.

Bulldog has also made posts advocating this method.

Definitely a very good thing.


GUI Grub Editor Info: http://www.ubuntuforums.org/showthread.php?t=228104.

Duplicate post from merged threads.

I did pretty much a similar thing, but as my BIOS had some strange issues about ignoring the HD boot order after the boot menu had been used I just changed the GRUB menu.list to also include Windows in the boot selection.

This way I can boot into either Ubuntu or Windows, and Grub/MBR problems only bring down one OS.

Quote:

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Originally Posted by Mojosdad

I did pretty much a similar thing, but as my BIOS had some strange issues about ignoring the HD boot order after the boot menu had been used I just changed the GRUB menu.list to also include Windows in the boot selection.

This way I can boot into either Ubuntu or Windows, and Grub/MBR problems only bring down one OS.

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I reckon that so long as you keep Grub on the Ubuntu drive your Windows should be safe enough.

thanks for the link to this gn2, but i don't think it would help me, given my situation right now.
i need the two OSs to be able to communicate, so i can back my windows stuff up on the linux drive, format the windows one and then restore the data again. having them ignore each other wouldn't help me too much. i get what you're saying though, which is a relief heheh

i'm more interested to hear how Mojosdad edited his grub menu.list to include windows heheh

I just had a read of your (weird_c00kie) other thread, and this one also..I'm having isssues with our desktop, and the kids hate having to select windows from grub (they're lazy).

This suggestion does seem like a workable one for 2 HDD's...The 2 OS's won't actually ignore each other, and once you have the whole mounting NTFS/Making Ext3 visible in Windows issues sorted, they should be able to communicate.

The only difference this should make is that, instead of having to select your OS through grub, you have to select it through the Boot Menu popup from bios.

Going to give this a try later and see how it goes methinks.

i'd personally find it more of a hassle having to go into the bios everytime than i would having to pick it at the grub screen, but maybe that's just me heheh

Quote:

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i'd personally find it more of a hassle having to go into the bios everytime than i would having to pick it at the grub screen, but maybe that's just me heheh

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Na, I totally agree with you.

Also considering not all BIOS' are the same or even have this F8 boot menu you are speaking of, Its alot easier just to install GRUB to the MBR of hd0. If there are any problems pop in a repair disk. 2 Minute fix. :D

Quote:

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Originally Posted by Khaotik

If there are any problems pop in a repair disk. 2 Minute fix. :D

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Only quick fix if all goes well......

And that doesn't always happen sadly.

Hey, I have the same problem. 2 hardiscks - 2 operating systems. First is Ubuntu, 2nd is WinXP. I waited for Grub to show the menu in which I would choose the OS but it only tells me to press ESC to enter the menu. I did so and WinXP it's not even listed! I'm a fresh Ubuntu/Linux user, I didn't even knew till today that there should have been a menu... I booted different OS by changing info in BIOS!:( Please, is there anyone there who could help me? Maybe enlight me a little bit? And, something else: I read somewhere else that is not a good idea to install Windows after Ubuntu (but I just found out that too...) Is it true? Help, help, help!