LiveUSBs

A LiveUSB is a bootable USB flash drive that contains a complete operating system capable of running directly from the drive without installing software on a computer’s internal storage. It is commonly used to test new systems, recover or repair machines, or carry a portable environment for use on multiple computers. Many LiveUSBs include a read-only base system and, optionally, a writable persistence layer that records user data and changes across reboots.

How it works can vary with the distribution. Typically, the USB drive holds a bootloader and a Linux kernel with an initial ramdisk. When the computer starts from the USB, the system loads the kernel and mounts the filesystem from the USB device. If persistence is enabled, a separate writable area or file stores changes so they remain after reboot. Without persistence, changes are lost when the system is shut down. Some distributions also support encrypted persistence for added security.

Creating a LiveUSB usually involves selecting an ISO image and a target USB drive with a tool such as Rufus, UNetbootin, balenaEtcher, or dd. The process may require enabling legacy BIOS or compatible UEFI settings and choosing the appropriate boot mode. The resulting device may vary in performance based on USB speed, drive reliability, and hardware compatibility, and some devices may not boot in certain environments.

Common uses include testing and evaluating a new OS, performing system maintenance or recovery, and providing a portable, privacy-focused or troubleshooting environment. Popular examples include Ubuntu, Debian Live, Fedora Live, Knoppix, Puppy Linux, and Tails.