Third grade textbooks in late 90s in Kochi, India teach us that a CPU has an Arithemetic Logic Unit and a Control Unit. A light pen is an input device that can

Third grade textbooks in late 90s in Kochi, India teach us that a CPU has an Arithemetic Logic Unit and a Control Unit. A light pen is an input device that can be held againt a Video Display Unit. They repeat this for a few years.