Today, real-time applications with critical constraints are usually run in an environment with Real-Time Operating System (RTOS). Services provided by RTOSs are severely exposed to faults which affect both functional and timing of the tasks running on the RTOS based system. In this paper, we introduce a new architecture for RTOS provides more robust services in term of Soft Errors (SEs). We evaluate and analyze robustness of the services due to SEs in two architectures, i.e. SW-RTOS and HW/SW-RTOS. Experimental results show more robust services were provided by HW/SW-RTOS versus purely SW-RTOS regarding SEs.