Yes they are. iirc, they run a modified kernel that is closer to realtime, and everything is a single thread for determinism. Code runs on a dual core processor

Yes they are. iirc, they run a modified kernel that is closer to realtime, and everything is a single thread for determinism. Code runs on a dual core processor, with one copy on each core, to detect bitflips. Three such modules are connected together in most places. I believe this is the setup they use for the main stabilization computer on each stage, as well as the engine controllers for each engine.