A few weeks ago, I wrote an article on How To Run Multiple X Sessions Without Virtualization, which demonstrated how you can run multiple desktop environments at the same time on the same computer, and switch between them at the push of a button. I admit, this was somewhat of a warmup for the real show – how to run multiple Linux distributions at the same time without having to deal with the drawbacks of virtualization software. Today, we’re going to be using chroot to treat certain parts of your Linux filesystem as (almost) completely isolated systems. This can let you do all kinds of interesting things, like run a full Gentoo system from inside your Ubuntu system with little to no performance loss.