“The stack on an iPhone is so deep. But in the early systems, you were closer to the metal. To really understand, you have to know how it works," he said. “My generation had such a leg up, evolving with this knowledge, as the computer gained complexity. There is so much young people can learn when they see how this evolved, about how people dealt with enormous technical constraints.” That’s how the building-size mainframes of old evolved into handheld internet phones with more computing power than NASA used to plant men on the moon.