UnoDOS: One OS, 22 Machines, From 8088 to Modern Laptops

UnoDOS is a contract-driven family of graphical operating systems that boots on 22 platforms, from an IBM PC/XT with an 8088 to modern x86-64 PCs. Its flagship, pc64, runs bare-metal on any UEFI PC with its own drivers, network stack, browser, office suite, compiler, and even a hypervisor that boots a real Ubuntu kernel. The original 16-bit real-mode OS fits a kernel, window manager, two filesystems, and 19 apps on a single 1.44 MB floppy.