Dual distros on a drive already devoted wholly to 1
Say I got Fedora on a USB and wanted to do a dual install. My drive is already set to have my Dreamlinux on it. The whole thing. If I were to do an install so I could have both fedora and Dreamlinux, Would it re-partition (I assume yes cause it has to go somewhere) and if so would I lose data or suffer any kind of loss, and how do I know what will be altered so I can back it up beforehand?