These thoughts are based on mine and my buddies' experiences in the interviews. Thoughts and comments are welcome.
One kind of interview: The interviewer's focus is mainly on testing what the candidate know and what he/she doesn't know rather than testing what he /she is capable of doing. The questions are mainly like Do you know this, what is this, whats the purpose of so and so API?... etc.
Another kind of interview: Consists of the questions like Given this situation how will you solve this problem? or Whats your approach to develop a module which can do so and so? Tell me some interesting situation you encountered in your prior experience or in your college? ... etc.
There are more differences, If the candidate failed to answer some question, the first kind of interviewer gives an insulting look which says "See, I have asked something which you are not able to answer?".
But on the other side second kind of interviewer tries to put the question in a different way, guides the candidate to what exactly the candidate is capable of doing in that context. Here the interviewer always try to focus on how the candidate is exploiting his prior knowledge and resources available, to produce the intended result.
Irrespective of the result, In the end, in the first kind of interview, the candidate comes out with a feeling that Oh my, I don't even know these simple things, I may not fit this job. But in the other situation, he comes out with a feeling that wow!, I discovered one more way of solving so and so problem.
One of the reason for the first kind of interviewers are more in our society is our education system which always focuses on what we know rather than what we can do in a given situation.
In my view there is no point in knowing or proving what a candidate doesn't know? But it will be very useful to know what he is good at and what he is capable of doing in a given situation.
