If you want to try out a new Linux distro, be it the latest Ubuntu 11.04 Natty Narwhal daily ISO or any other (I’ve only tested it with Ubuntu though !) and don’t want to burn a CD each time you want to try a new daily build (and you don’t have an USB memory stick around), you can use a cool GRUB 2 feature that lets you boot a live CD ISO directly from your hard disk. You can also use this method to boot varous utilities such as Super Grub Disk, SystemRescueCD, Parted Magic and so on.

Usually, setting up GRUB 2 to boot an ISO can be quite a difficult process (well, not that difficult but for some reason it always failed for me) but you can do this with just a few clicks thanks to Unetbootin.

In Ubuntu, simply run the following command to install it :

sudo apt-get install unetbootin

If you’re not using Ubuntu and Unetbootin is not in your distro official repositories, download it from HERE.

In Unetbootin, select the "Diskimage" option, then browse for an ISO and under "Type" select "Hard Disk" and leave "/" for the "Drive", then click OK :

Once Unetbootin finishes, restart your computer and select "Unetbootin" in the GRUB2 menu. If the Grub2 menu doesn’t show up, press and hold the SHIFT key.

Because Unetbootin extracts the ISO, you’ll have to run it again when you want to boot a new ISO, even if it has the same name and is placed in the same location as the old one.

The next time you’ll launch Unetbootin, it will ask you the following : "Unetbootin is currently installed. Remove the existing version ?" - this isn’t about removing Unetbootin but about removing the Grub2 menu entry for Unetbootin (and the ISO). Select "OK" and the ISO will be removed from the menu.