An anonymous reader writes "Have you ever heard of an OS which fit inside a Floppydisk ? Maybe Not. But there is.It is known as KolibriOS. KolibriOS (also known as KOS and Kolibri) is a free operating system with a monolithic preemptive, real-time kernel, video drivers, for 32-bit x86 architecture computers, developed and maintained by The KolibriOS Project Team. Its only 2.4 MB in size."