Image via WikipediaBoot and run Linux from a USB flash memory stick | USB Pen Drive Linux
USB Linux installation enables you to install a portable Linux operating system on a flash drive or USB key no larger than your thumb (thumbdrive). This portable Linux operating system can then be run from any computer that can boot from a flash device, allowing you to bring your operating system, desktop, applications, files, email, personal settings, favorites, games and more with you. It’s your own personal operating system you can carry in your pocket. On Pendrivelinux.com, we provide many simplified portable Linux flash drive installation tutorials. Making is easy for anyone to install, boot and run Linux portably from a Pen drive!