Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Simple question, I have two drives, Drive A and Drive B. I have Windows XP installed to Drive A and I want to install Ubuntu to Drive B. Is there a way to install Ubuntu to Drive B without it modifying (like updating the boot loader) to Drive A?

I want each OS to have no knowledge of the other at boot time. I know that Windows and Ubuntu will be able to see all drives on the system, etc.


@Ryan & @tj111: This a work machine so I really don't want to update Drive A in any way. I have no problem going into the BIOS and updating the boot order manually

@EvilChookie: Yes, Drive A and Drive B are physically separate hard drives (A is 100GB and B is 1TB). They are NOT partitions.

share|improve this question
I don't think it can be possible, because when you turn on pc how should it know how many OS you install and where it's boot loader? then one of you installed operating system must have all boot information. – Am1rr3zA Aug 28 '09 at 20:53
Are drives A and B physically separate drives? If not, you may want to edit your question to say you have two partitions, for greater accuracy and less confusion. – EvilChookie Aug 28 '09 at 20:58
You should be able to follow the instructions in my answer then, but just turn off A in the bios without physically unplugging it. It's still more paranoid than you need to be, but it will guarantee that ubuntu won't modify drive A at all. – Ryan Aug 28 '09 at 21:02
@Chris: I am pretty sure you can use Ryan's answer and just skip the part where you add grub to be a boot manager. Then you should just be able to go into the BIOS and change the boot order. Be sure you unplug the WinXP drive, though, during the install. – Jared Harley Aug 28 '09 at 21:02

I disagree with the other answers, in that "no knowledge of each other" is well possible. It might not be very practical though.

A configuration I ran in the old times was like this.

  • Windows on Drive A, booted by windows bootloader as usual
  • Linux on Drive B, no boot loader

A 3.5" diskette with the bootloader for Linux on Drive B. I used the diskette as a boot "switch". When it was in the diskette drive my machine booted Linux, when it was not in the drive the machine booted windows. It is probably possible to do the same with an USB drive.

In the old days there have also been boot diskettes that were able to swap the boot drive order. They offered a menu which allowed you to boot from the first or the second harddrive without knowing anything about the installed OS.

What I have nowadays is a machine with no internal harddisks at all. I have a bunch of eSATA drives I connect ad libitum.

share|improve this answer
Good idea (as long as the computer has a disk drive, as so few today seem to!). If your machine is new enough, you should be able to use a small USB key to the same effect by telling your bios to prefer USB drives first. – Jared Harley Aug 28 '09 at 21:04
It's possible to store the Linux boot loader on drive B without affecting drive A. Thus bot OSs are completely unaware of each other. You only need to change the boot order in BIOS to boot from the correct drive. I did this a while ago but found it a bit annoying: if you miss the time window to enter the BIOS your need to reboot which is time consuming. – wierob Aug 28 '09 at 21:48
@wierob: exactly – Ludwig Weinzierl Aug 29 '09 at 9:05

"no knowledge of each other" is impossible, depending on how you define it. Something has to be aware of both OS installs.

You definitely can install to Drive B without touching Drive A, though.

Basically, you need to make Drive B first in your BIOS boot loader, then configure GRUB (a small boot-loader program) to know about the windows installation on Drive A.

If you want to make super-duper sure that Drive A isn't touched during the install, I'd do the following:

  1. Unplug Drive A, physically remove it from the case.
  2. Give Drive B boot priority in the BIOS
  3. Use the Ubuntu CD to install it on drive B.
  4. Plug Drive A back in, make sure that it still has lower boot priority in the BIOS
  5. Use any of the many fine GRUB tutorials out there to tell GRUB where windows is.

Then your bios will Boot GRUB, which will give you a choice of either Windows or Ubuntu.

share|improve this answer
This might not work because of different references of the drive. – txwikinger Aug 28 '09 at 21:01
Your BIOS may even give you the option to prompt for a boot device, making the process a whole lot easier - each drive can consider itself the only drive, no nasty boot loaders or anything like that. – EvilChookie Aug 28 '09 at 21:04

Ubuntu by default will install it's own boot-loader (grub), and add any other OS's it detects to it's boot menu, there by allowing you to dual boot easily. They don't know anything about eachother, and it won't affect the windows boot sequence in any way. Just out of curiosity, how do you plan on booting to the other OS without a change in the boot-loader?

share|improve this answer

It depends if your BIOS allows you to boot from drive B. If it does, you install Ubuntu as normal, but after the partitioning there is an advanced option allowing you to define where the boot loader is to be saved. Put in the reference for Drive B.

If your BIOS does not allow you to boot from Drive B, but the boot loader on a floppy or usb stick and boot from there instead.

share|improve this answer

I would remove the drive you do not want to touch and install Ubuntu then re-connect the windows drive.

At this point you will have two bootable drives but your computer can only boot from one at a time.

So now you can either manually adjust BIOS to boot from the correct disk each time you want to change OSs or configure GRUB to offer a selection of which OS to boot. If using GRUB/Ubuntu to handle the boot you'd obviously need to have your computer's BIOS set to boot from the Ubuntu disk.

This process will not change your Windows drive at all.

share|improve this answer

When I was still trying out different distros I once had this setup: I installed linux on an external hard drive and told the bios to boot from that. If the external drive wasn't connected at boot time, the bios would boot from the internal one. The only thing you need to do is tell linux to install itself on the external drive. If something goes wrong there, you can always restore windows' mbr and install grub manually.

share|improve this answer

Just a thought but would the EFiX devices that are used to build hackintoshes allow this, as I understand these devices they extend the bios to allow it to control things like multiple OSes independently that's how they allow OSX to cohabit with other OSes on hackintoshes.

share|improve this answer

If you have no problem going into the BIOS everytime, just disable the "other" drive in the BIOS and no operating system in the world will be able to "see" it. Hardly worth the effort, though. It is not like Windows and Linux hate each other and try to destroy their "enemy" when they see that another OS is installed.

Adding Linux to the windows bootloader is not a mayor thing, it just means adding a bin file to C:\ and editing the bootloader configuration. There are tons of howtos on the web and there is not a lot that can go wrong if you are careful.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .