How do I boot from an external hard drive that has ubuntu on an imac?

Question

I just installed ubuntu(hardy 8.04) into my external hard drive and I am trying to boot ubuntu from that external hard drive on my imac but every time i pressed C, command-option-shift-delete, command-option-shift-delete-#, command-option-esc but nothing happens except that it loads on the mac os x.

I also tried pressing the option key and all i get is a choice between mac and windows but nothing else. Is there a way to access that external hard drive while booting? And I would prefer a mac user to answer this question or ubuntu user to answer this question.

Answer 1

Go into the BIOS and set your computer to boot from the F, G, ect driver (the one the external hdd is) than restart your computer and it should boot from that.