While most operating systems are written in C and C++, KolibriOS is written in pure x86 assembly and as a result small and lightweight enough to run off a standard 1.44 MB floppy disk, as ...
It has a 386DX running at 25MHz, 4MB of RAM, a 300 MB hard drive, VGA, and an Ethernet NIC. Gathering the requisite CRT monitor, PS/2 keyboard, and an AUI to a more modern Ethernet connector.