@Joseph, am I really ignorant in asking questions why a genius programmer so good as Linus, who probably would have created another computer language or even a better electric car or green energy would sit at his desk and write a reverse engineered code for a propreitary system at that time? What would drive such a talented person to do this? All the genius computer people of that time gave the world programming languages, am sure if they wanted to reverse engineer anything, it would be child's play for them.

@Muendo, thank you. Ken Kasina and what he did on BSD knows much much more than a bunch of linux operating system admins. I hope he will share his insights into this valuable thread as a coder. If only he was an active contributor to this list, he would be such a valuable contributor and an inspiration.