NixOS 14.12
http://nixos.org/
.669NixOS is an independent, functional and usable GNU/Linux distribution that uses the KDE Plasma Workspaces and Applications as its default desktop environment. It is called NixOS because it’s based on Nix, a purely functional package management system.
Nix is similar to APT and YUM

Similar to APT and YUM, the Nix package manager makes sure that no package is broken during upgrades. It also manages boot scripts, configuration files, and other similar files that are involved in the package management of a Linux distribution.
It can only be installed, no live mode!