Shawn Hymel takes a look at real time operating systems for hardware focusing on Zephyr and FreeRTOS.

Every time I mention Zephyr, I inevitably get a few responses along the lines of “just use FreeRTOS.” I admit, FreeRTOS is amazing, but it might not be the right tool for the job. In the rest of the post, I’ll analyze each to hopefully help give you a better idea of what kinds of jobs each is better suited for.

The first question you should be asking is if you even need a real-time operating system (RTOS). I covered this in a previous post, but the basic answer is that if your embedded project is complex enough, it might be worth looking at using an RTOS.

At a basic level, an RTOS gives you deterministic scheduling, task isolation, synchronization primitives, and timing guarantees. Many modern embedded systems demand more than just a scheduler, especially once connectivity, security, portability, and long-term maintenance enter the picture. Connectivity, security, portability, and long-term maintenance often end up mattering just as much as real-time performance.

See the analysis in the post here.