A simple single board computer using a Motorola 68010 CPU, which can connect to a host computer via USB/TTL-Serial. It has a bus for connecting a supervisor arduino or expansion devices, but it can operate standalone using the onboard UARTs. It has 1MB of onboard Flash, 1MB of onboard SRAM, and a 68681 Dual UART chip with GPIO. Some of the GPIO pins are wired to 4 general purpose LEDs and 2 general purpose buttons. The SMT version has a CompactFlash socket directly interfaced to the CPU.
Along with it is a Unix-like OS that can do preemptive multitasking using the 68681 timer. It also has an implementation of the Minix version 1 filesystem, which uses RAM (through a device driver) to store the data, or a Compact Flash card connected as an IDE device. The second serial port can be configured as a SLIP device, with a basic implementation of UDP and TCP through a BSD sockets-style API, and an NTP command is provided for updating the system time on boot (when booting from disk).
I've been working on an emulator written in Rust called Moa which is capable of emulating Computie. It will open two pseudoterminals on the host linux computer for the TTY and SLIP connections that Computie OS uses, and launches a terminal emulator to connect to the TTY. Check it out on github for more info