In this paper, the authors present a Hardware-Real Time Operating System (Hw-RTOS) for multiprocessors. A virtual platform (SystemC) and prototyping platform (FPGA board) have been designed to be generic, modular and to support multiprocessor architectures and the Hw-RTOS. Thus, they can customize functionalities and scope of platforms according to the needs of an application. The Hw-RTOS offers classical OS services, new services to improve multiprocessor management (migration of tasks) and possibilities of scheduling analysis. Indeed, these platforms can be also used to develop new scheduling algorithms to improve the load balancing but also to take into account others parameters such as low power parameters.