10 mb Linux with GUI Desktop. It is based on Linux 2.6 kernel, Busybox, Tiny X, and Fltk. The core runs entirely in ram and boots very quickly. Also offered are Micro Core, a 6 MB image that is the console based engine of Tiny Core, and Multi Core, which includes Tiny Core, Micro Core, networking tools and an installer. Micro Core contains CLI versions of Tiny Core's programs allowing the same functionality of Tiny Core's extensions, only starting with a console based system. It is not a complete desktop nor is all hardware completely supported. It represents only the core needed to boot into a very minimal X desktop typically with wired internet access .....(free).....