KNOPPIX is a bootable Live system on CD, DVD, or USB flash drives, consisting of a representative collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices, and other peripherals.
KNOPPIX can be used as a productive Linux system for the desktop, educational CD, rescue system, or adapted and used as a platform for commercial software product demos.
It is not necessary to install anything on a hard disk. Due to on-the-fly decompression, the CD can have up to 2 GB of executable software installed on it (over 9GB on the DVD "Maxi" edition).
MultiBootUSB is a software installer that allows the user to install multiple Live Linux Distros to a single USB drive/Pendrive/Flash drive and boot from it.