uSmartx is a non-preemptive, multitasking, priority based kernel for use in embedded designs. Its major features are task and time control over system resources, inter task communication and simple memory management.
ftRTOS is a tiny realtime kernel for microcontrollers focused on minimal RAM usage. Fixed priority scheduling, preemptive or cooperative multitasking, no dynamic task and memory management, all objects are defined at compile time.