os8088: A Mac-like OS for the IBM XT, 286, 386

Os8088: A powerful Mac-like OS for the IBM XT, 286, 386

os8088 is a graphical operating system for the IBM PC XT, written entirely in real-mode assembly and booted from a floppy. It brings a Macintosh System 1-style desktop to 8086/8088 machines, featuring overlapping windows, pull-down menus, a serial mouse, and pre-emptive multitasking—something the original 1984 Macintosh lacked. The kernel fits in 52,718 bytes, runs in 256K of RAM, and supports VGA, Hercules, or CGA displays. Programs load from a second floppy and run concurrently, with a Task Manager showing CPU usage. It runs on real hardware, including a 1981 IBM 5150, and is a hobby project with source available.