AO RTOS is small real time OS based on Active Object concurrency model
A multi-threading framework using a prime sieve to do work
Simplest kernel for cooperative multithreading
Real time preemptive embedded multi-thread kernel
Ping-Pong-like game in Assembly that works without OS
A UNIX-like kernel for the i386 architecture
Mulithreading Arduno library
Embedded Real-Time Operating System (RTOS)
Operating System in 512bytes.
A cross-platform «Boulder Dash»-like game in Oberon/Component Pascal