- DevLib - Homebrew library for embedded development that includes a small multitasking kernel.
- uClinux - A Linux kernel and distribution targeting several MMU-less microcontrollers.
- Nut/OS - Nice OpenSource RTOS for 8/16/32bit systems. See software .
- FreeRTOS - Yet another OpenSource RTOS. See http://www.freertos.org/ .
- QNX - A microkernel RTOS with a wonderful system architecture.
- AmigaOS - Almost an embedded OS, and definitely an RTOS.