Writing tiny apps for small constrained systems isn't difficult at all. That's what we did thirty years ago. One neat trick is to use threaded interpretive lan

Writing tiny apps for small constrained systems isn't difficult at all. That's what we did thirty years ago. One neat trick is to use threaded interpretive languages (FORTH). https://en.wikipedia.org/wiki/Apollo_Guidance_Computer https://en.wikipedia.org/wiki/Apollo_Guidance_Computer https://en.wikipedia.org/wiki/IBM_System/4_Pi https://en.wikipedia.org/wiki/IBM_System/4_Pi https://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html https://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature... The minute you start touching modern languages and OS's things become significantly more difficult to shrink into small platforms.