Embedded processors are widely used in critical applications such as space missions, where reliability is mandatory for the success of missions. Due to the increasing application complexity, the number of systems using Real-Time Operating Systems (RTOSs) is quickly growing to manage the execution of multiple applications and meet timing constraints. However, whether operating systems or bare-metal applications provide higher reliability is still being determined. We present a comprehensive reliability analysis of software applications running on a device with bare-metal and FreeRTOS against the same faults based on fault models derived from a proton test. Additionally, the FreeRTOS system has been evaluated with a set of software applications dedicated to evaluating specific RTOS functions, providing an additional evaluation for operations crucial for a real-time operating system
