Just a post of an indirect analogy here of the methodologies of function.
Your knee will jump if you tap it just in the right spot near and below you knee cap. This is called the Patellar reflex.
Striking the patellar ligament with a reflex hammer just below the patella stretches the muscle spindle in the quadriceps muscle. This produces a signal which travels back to the spinal cord and synapses (without interneurons) at the level of L3 in the spinal cord, completely independent of higher centres. From there, an alpha motor neuron conducts an efferent impulse back to the quadriceps femoris muscle, triggering contraction. This contraction, coordinated with the relaxation of the antagonistic flexor hamstring muscle causes the leg to kick. This is a reflex of proprioception which helps maintain posture and balance, allowing to keep one's balance with little effort or conscious thought.
The patellar reflex is a clinical and classic example of the monosynaptic reflex arc. There is no interneuron in the pathway leading to contraction of the quadriceps muscle. Instead the bipolar sensory neuron synapses directly on a motor neuron in the spinal cord. However, there is an inhibitory interneuron used to relax the antagonistic hamstring muscle (Reciprocal innervation).
A pacemaker (software/firmware) talks to the Purkinje fibers which is your second brain. A glitch here in software will kill you. I am not saying that it doesn't work here.
(Purkinje fibers are special fibers that are located in the atrioventricular, or AV, bundle of the heart. Their function is to send nerve impulses to the cells in the ventricles of the heart and cause them to contract and pump blood either to the lungs or the rest of the body.) Best methodology though is to beat the heart (literally) or shock the mini brain in to submission sometimes.
Simple and functional firmware in the aforementioned combination security / automation panels relates to speed of action or response time.
Adding slush to this via software is like thinking about a reflex and having to think about bypassing the pathway while concurrent checking it.
Today you drive a car or fly a plane which still utilizes a base of old serial bus (the meat) for vital communications mostly because it just works. (unrelated / related - read about an aerodynamic stall).
Air France Flight 447 (AF447/AFR447) was a scheduled passenger flight from Rio de Janeiro, Brazil to Paris, France, which crashed on 1 June 2009. The Airbus A330, operated by Air France, entered an aerodynamic stall from which it did not recover and crashed into the Atlantic Ocean at 02:14 UTC, killing all 228 passengers, aircrew and cabin crew aboard the aircraft.
The Brazilian Navy removed the first major wreckage and two bodies from the sea within five days of the accident, but the initial investigation by France's Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA) was hampered because the aircraft's black boxes were not recovered from the ocean floor until May 2011, nearly two years later.
The BEA's final report, released at a news conference on 5 July 2012, concluded that the aircraft crashed after temporary inconsistencies between the airspeed measurements – likely due to the aircraft's pitot tubes being obstructed by ice crystals – caused the autopilot to disconnect, after which the crew reacted incorrectly and ultimately caused the aircraft to enter an aerodynamic stall from which it did not recover. The accident was the deadliest in the history of Air France. It was also the Airbus A330's second and deadliest accident, and its first in commercial passenger service.