Sulfur dioxide (SO2) is irritating to eyes, skin and respiratory system. Volcanic Smog (vog) is produced from SO2 gas and is a hazard in Hawaii. Scientists monitor SO2 emission rates at KÄ«lauea volcano. Gas Plume during the 1984 eruption of Mauna Loa, Hawaii blocks out the sun.
Control Unit (CU) A control unit (CU) handles all processor control signals. It directs all input and output flow, fetches code for instructions from microprograms and directs other units and models by providing control and timing signals.
Engine Control Unit - Controls only the engine and that is it. Power Train Control Module - Controls the engine, transmission, and other pieces. May still have slave modules that are external to the master module such as the Transmission Control Module for automatic transmissions. The distinction here with PCM is that typically the TCM is useless without the PCM.