Installing onto an external HD

The best way to do it is to install it from the CD. Burn Ubuntu 10.04.1 on a CD, put it in your CD ROM, than plug in your external hard drive into the USB port. Than restart your computer, set your CD as a first boot device in BIOS, and when installation begins, just set that Ubuntu installs on your external drive, and that´s it.

Actually there is one important step during install that you need to follow! Grub needs to be installed onto the external drive as well! By default it is going to install onto your first hard drive and NOT the external! During install there is a button to get advanced options for Grub, it's right near the end of configuration, before the copy/install starts - you need to manually select to install Grub onto your external drive.

Best of luck,
George

No need to shout George;-)

Allison, here is that step where you have to specify where to install Grub bootloader:

http://img718.imageshack.us/img718/2167/prikazzaslonau.png

So you can do as I said earlier, but will have to manually select to install Grub on your external drive too, as George said.

Grub comes in many pieces:
a) three hundred bytes copied into MBR (first disk sector) of first disk by default
b) two disk sectors at start of Ubuntu partition
c) a folder in Ubuntu partition
The joke with external drive is, if you not do properly, the MBR of internal disk is modified and the others boot files are on external media.
So:
1) When you try to boot alone internal disk, it can not load files of "/boot" partition and you have no boot at all (including local Windows OS)
2) When you try to boot alone removable media, is has not the right MBR, and stop immediately.
It's why George is shouting a little, because you will have problem on BOTH computers.

Sorry, I did not know that.. Well it is a complicated procedure a bit.

Maybe the solution would be to unplug the internal hard drive, and do the installation only with external drive plugged in.

Or start Ubuntu Live CD, and install Ubuntu on the external hard drive using System>Administration>USB Startup Disk Creator. But, if he installs Ubuntu using USB Startup disk creator, the external drive will act as a Live CD, and Ubuntu will not really be installed on the external hard drive.

First solution should work. And second one also. For second one, Ubuntu installer will have no choice but to install all on external drive. And this external drive will be used as a internal drive to boot. Only difference is that it will be name sdg instead of sda. So you have choice. Personally, I will choose second one, as installation is done directly on the right hardware.