Many moons ago, I had a friend who was a nuclear engineer at a power plant. His plant didn't have a separate computer network for the reactor simply because computers weren't allow to connect to the reactor. Anything piece of hardware with enough complexity to achieve Turing completeness was forbidden. When he wanted to add a monitoring circuit somewhere that included more than some piddly number of transistors, he had to document ever possible state that the system could enter.

We also occassionally use "light" as an antonym for "heavy".