In the aftermath of Hurricane Katrina the humble CD proved a vital implement in the recovery effort - in a triumph of fundamental technology over multi-million dollar solutions. But they weren't just ordinary CDs, they were Linux-based operating systems known as LiveCDs. If you're not familiar with LiveCDs, they are simply an entire OS, and usually additional applications, that boot from removable media without requiring any installation, leaving the hard drive (if any) untouched.