I have already been through such interview, and 1st hour was a ad-hoc technical conversation, with last 30 mins questions of the candidate about the workplace.

I have already been through such interview, and 1st hour was a ad-hoc technical conversation, with last 30 mins questions of the candidate about the workplace. I don't think the length should be the problem. On the other hand, I wouldn't mind short-circuiting the interview.