AO RTOS is small real time OS based on Active Object concurrency model
freeRTOS for Arduino Uno, Goldilocks 1284p & Mega 2560
The smallest and the most powerful operating system.
Linux kernel driver for Xbox One and Xbox Series X|S accessories
Open-source RTOS and Embedded Systems Toolkit for C++ and C
Tool allowing you to put a Linux distro on a USB drive.