HartOS - a Hardware Implemented RTOS for Hard Real-time Applications

This paper introduces HartOS, a hardware-implemented, micro-kernel-structured RTOS targeted for hard real-time embedded applications running on FPGA based platforms. Historically hardware RTOSs have been too inflexible and have had limited features and resources. HartOS is designed to be flexible and supports most of the features normally found in a software-based RTOS. To ensure fast, low latency and jitter-free communication between the CPU and RTOS, HartOS uses the ARM AXI4-Stream bus recently supported by the MicroBlaze softcore processor. Compared to μC/OS-II, HartOS has up to 3 orders of magnitude less mean error in generating the correct period for a periodic task, and around 1 order of magnitude less jitter, while having up to 100% less overhead depending on the tick frequency.