An old joke in hardware engineering circles says, contrary to popular belief, electronic gizmos don’t run on electricity. They run on smoke. When something goes wrong, the smoke (sometimes accompanied by flames) escapes, and the device stops working.

What’s a computer?

Ask anyone that question, and you’ll probably get variations of, “A machine with a screen and a keyboard and pointing device, used for running various software programs.” This has been the general “high-level” definition since the personal computer became popular in homes and businesses in the early 1980s.