Live USB

A live USB is a portable USB-attached external data storage device containing a full operating system that can be booted from.

They are the evolutionary next step after live CDs, but with the added benefit of writable storage, allowing customizations to the booted operating system.

To set up a live USB system for commodity PC hardware, the following steps must be taken: Knoppix live CDs have a utility that, on boot, allows users to declare their intent to write the operating system's file structures either temporarily, to a RAM disk, or permanently, on disk or flash media to preserve any added configurations and security updates.

However, full installation is not without disadvantages; due to the additional write cycles that it requires, the life of the flash drive may be slightly reduced.

Beyond these, another factor to consider is that, if the transfer speed of the storage device is poor, then performance can be reduced to a rate more typical of legacy computers – even for machines with modern components.