The Interview Question That Tells Me Everything (opens in new tab)

I would love to be asked this question in an interview. For context, I first learned to program in BASIC, Logo and assembly on an Apple IIe. I have a computer science degree where we studied CPU architectures, operating system implementations, etc. I worked in telecommunications for many years. I have a hobby interest in electronics. I also have a hobby interest in physics, especially quantum physics. If I had a whiteboard to keep track of what I was talking about, I think I could comfortably talk for well over an hour. For example, did you know that when an electrical signal flows through a wire, the majority of the energy flows outside the wire rather than via the movement of electrons within the wire? Did you know that electromagnetism is actually part of the electroweak force and that fact was proved by the LHC's discovery of the Higg's boson? Did you know that activity in someone's motor cortex is already spiking before they are consciously aware that they have "decided" to press the enter key? Did you know that twisted pair ethernet cables are twisted to reduce the effect of interference? Did you know that most ethernet hubs these days are actually switches and so CSMACD is rarely needed anymore? If it's https then the browser is validating the server's public key. The TLS connection is established by a key exchange protocol but most traffic is encrypted my symmetric encryption because it less CPU intensive? Most CPUs these days have special instructions for speeding up crypto calculations. It's probably a TCP connection. Some websites (like google) put a lot of effort into sending the landing page in few enough bytes that TCP flow control won't kick in and oblige the client to acknowledge receipt of any packets before the whole page is sent (although some rules are bent here to achieve this). Data is usually compressed by the server before encryption, gzip compression uses lempel ziv and huffman. Images are probably JPEG with a very interesting compression scheme. If there's javascript in the page I can talk about the implementation of language in a browser. On so on.

> You can’t fake this answer. There’s no leetcode trick, no memorized regurgitation. You either have the paint drips or you don’t. And if you don’t, maybe this question sparks your first one.

https://github.com/alex/what-happens-when

This question is well known and people do indeed prepare for it.