UnoDOS

UnoDOS is a family of graphical operating systems designed to run across multiple platforms, from vintage machines like the IBM PC/XT to modern 64-bit computers. The project began as a 16-bit real-mode OS written entirely in x86 assembly that fit on a 1.44 MB floppy, and has since expanded to support 22 different machines including home computers, consoles, handhelds, and mobile devices. The flagship version, pc64, runs bare-metal on modern 64-bit PCs with its own drivers, network stack, browser, office suite, compiler, and hypervisor.