Installation on a Mac

[sbredflag]

Hi, I'm an absolute beginner to the linux scene, and I'm trying to install Ubuntu. I've looked in many places, and searched these forums, but no topics answer my questions exactly.

Here is my situation:

I have an iMac with a 250GB Hard Drive, of which I am using around 70GB. I also have a 150GB external USB drive (unfortunately, I found that you can't boot off of a USB drive) I have a Ubuntu CD I burned, as well as the 2 OS X discs that came with my computer.

My question is: How can I set it up so that I can choose on the boot screen by holding down 'alt' which OS I will load (so both OS's will be in my hard drive),ubuntu or mac os x without losing any memory from my computer hard drive (my external hard drive can be erased as needed)? I can partition my hard drive, but I need to know how to back up all of the information on my hard drive to my external drive, and then restore it.

Feel free to ask me any questions about my computer specs or anything else (that is relevant) if more information is required.

Since I'm a newbie, detailed help is appreciated. (So no technical talk for me :-P)

Thanks in advance for any help you might be able to offer:)

[alexandro121]

http://refit.sourceforge.net/

install it using mac... then when you strat up you mac the refit logo will apear and it will give you the option to choose with op sys want to use ......

check for tutorial

[sbredflag]

Ok, yeah, but does it let me partition my drive and install ubuntu? Or does refit let me boot from my USB? That's what I need help with.

[Kooothor]

Yeah refit is good, and it'll let you boot from an usb key also.

[sbredflag]

So this is how I'll do it?
1.Install Ubuntu to my USB drive (How would I do this? Can I just use the installer and select which drive to install it to?)
2. Install refit
3. reboot, and using refit, boot Ubuntu

Or am I not understanding something?

[sbredflag]

Sorry for the double-post, but I decided to do it on my main hard drive using boot camp. I used this website as a guide. (In case anyone else was looking for the same thing as me)

http://www.helium.com/items/421906-how-to-install-linux-on-an-intel-mac-with-boot-camp