This is an age old interview question and a very pertinent one. I first came across this two years ago and was very impressed with the explanation given by the author. But I am not able to get hold of the link now. I was doing some googling today and came across these resources.

github.com/alex/what-happens-when

plus.google.com/+JeanBaptisteQueru/posts/dfydM2Cn…

superuser.com/questions/31468/what-exactly-happen…

These are good resources but nowhere close to what I had ready. So am reaching out to the community. What are the best responses you have read for this question?