IPython Kernel for Jupyter
Linux Kernel Manager and Activity Monitor
Hobby operating system, bootloader, kernel, drivers, C library
AO RTOS is small real time OS based on Active Object concurrency model
Thread Scheduler with custom asynchronous messaging in VC++
An little operating system
Open-source RTOS and Embedded Systems Toolkit for C++ and C
Java dwarf library
Forth & Lisp Operating System
A microkernel, capability-based operating system for the Cloud.