Google

Coding problems, then system design questions. Walk through your solution. Clarify with the interviewer. System design questions: How would you build a hypothetical architecture? Discuss the pros and cons of your chosen solution.

Around 5+ hours, with a few minutes in between sessions. Pretty straightforward, nice people. It's paramount that you ask questions and keep the interviewer involved during the process. If you have to speak your thoughts out loud, do that. It is be

I had two back-to-back interviews at one of Google's offices. The first interviewer was awesome, but the second was very reluctant in answering questions I had about the parameters of the questions.