Summary

In this chapter, we explored the typical components of an embedded operating system by implementing one from scratch, with the only purpose of studying the internals of the system, how the various mechanisms can be integrated into the scheduler, and how blocking calls, driver APIs, and synchronization mechanisms can be provided to tasks.

We then analyzed the components of two of the many very popular open-source, real-time operating systems for embedded microcontrollers, namely FreeRTOS and Riot OS, to highlight the differences in the design choices, implementation, and APIs provided for the applications to work with threads and memory management.

At this point, we can select the most appropriate OS for our architecture, and even write one ourselves when needed, by implementing our favorite scheduling, priority mechanisms, privilege separation between tasks and the kernel itself, and memory segmentation.

In the next chapter, we will take a closer look at Trusted Execution...