snyder_24

Hello,

I am wondering if there is a way to put Ubuntu on my external hard drive. But I also want to be able to choose which OS to use when I start my computer. I am using Vista on a laptop right now. I don't know anything about partitions and what not, so any advice and/or walk-through would be welcome!

Bartender

Does your BIOS support booting from an external drive? Most modern BIOS'es do. You'll have to research this a bit. There should be a keystroke or keystroke combination that you hit while the computer is starting up that lets you choose which device to boot from. If you see the Windows logo you missed it, hit the wrong keys, or it doesn't exist. Let's assume it does exist, you googled around a little bit and found the keystroke(s) for your BIOS, and you figured out when to hit the key(s).

Wait, wait, another thing to do is start up the PC with the external plugged in, and actually go into BIOS. Whatever keystrokes are involved to do that. Once you're into BIOS, find your way to "Bootable Devices". If you see the external in the list, then your BIOS supports booting from an external and you should be able to use the keystroke combination described above to choose which device to boot from.

OK, so back to the first part: if your BIOS supposts boot from external, you should be able to hit the keystroke combo and a list of bootable devices will show up. If Ubuntu (and GRUB the bootloader) was installed to the external correctly you should be able to pick the external, tap "Enter" and the BIOS will be directed to boot from that device.

There must be a million threads on the nuts-and-bolts of installing Ubuntu to the external. Just be aware that you need to make a decision on how to install GRUB, which is the bootloader for Linux.

Windows won't start without its Master Boot Record, a small scrap of code that has to be installed to the front of the HDD. By the same token, Linux won't start without its bootloader. Ubuntu uses GRUB.

GRUB will by default tweak the Windows Master Boot Record so that you have a choice of operating systems at startup. This works fine when both operating systems are on the main HDD inside the PC. That's because both OS'es are right there at start-up.

In your case, letting GRUB auto-install to the Windows MBR is probably not the right choice. Once GRUB has been installed to the Windows MBR both operating systems have to be installed and visible to GRUB! If you let GRUB auto-install to the Windows MBR, then try to start the PC without the external plugged in, all you'll get is a GRUB error. Nothing's gonna work.

So, although I've never done what you want to do, I'd imagine the way most people do it is install Linux and the Linux bootloader, the whole enchilada, to the external. Then they use their BIOS to choose which device to boot. That way Windows will still work when you don't have the external plugged in.

Also, I imagine that unless you have eSATA, running an operating system from an external on the USB interface will probably seem a bit slow.