I recently interviewed with a startup. They had all 6 engineers interview me one by one. Each interview had a whiteboard/tech question component. At no point

I recently interviewed with a startup. They had all 6 engineers interview me one by one. Each interview had a whiteboard/tech question component. At no point in time was I restricted to a language or expected to use an API. The questions measured an understanding of algorithms (data structures and big-O notation), an understanding of operating systems (concurrency, memory allocation, etc.) and object oriented programming. There was even a gross bithack, which I really struggled with. After a half hour the interviewer was laughing, saying "I love this problem because everyone just goes bananas with it". It wasn't to make me look stupid, it was to see how I approached a problem that was apparently unsolvable. With each question I was free to ask any questions, whether it was a clarification on pthreads or a question about problem constraints. I did not feel like my "off the cuff" knowledge of programming was being tested, but rather my experience and understanding of programming. My only complaint with the interview was that it was long (11am - 7pm with a lunch break). That was mostly due to the fact they wanted me to meet with the entire team one at a time, as well as the fact that I was only in town for the day.