I want to backup my Macbook Pro and Windows/Ubuntu machine. Here's what I'd ideally like to do: back them up to a cross platform readable file (ISO?), so I can access the data on any machine, be it Mac or PC. I could also if I wanted simply boot from the Mac ISO if I was on a Mac or the Ubuntu or Windows ISO if I was on my other machine. So the question: How do I do it? I tried creating a .dmg image of my Macbook Pro last night, but when I double clicked it it said that no mountable systems were found. Did I do anything wrong? Also, I don't want to burn anything to a CD. I simply want to store the three ISO files on an external hard drive.