Knoppix is a Debian-based operating system that can be run directly from a CD, DVD, or USB stick. It is a Linux distribution that is popular for its live CD/DVD functionality, which allows users to boot into a full-featured desktop environment without the need to install an operating system. It is a great choice for those who need a fast and easy way to try out a Linux-based operating system without any hassle. Knoppix includes a wide range of open-source software packages from the Debian repositories, as well as a variety of tools for system administration, hardware detection, and troubleshooting. It is also often used as a tool for recovering data from crashed systems or as a rescue disc.
Raspbian cannot work completely from RAM
FalconFour discontinued seems to be abandoned, no more updates since 2013.
Discontinued The program seems to be no longer updated. The latest version, 2.9.4, released in September 2015, can still be downloaded from the official website.