That was 3 years ago. Maybe if you had told me I would have to answer that question I would have reviewed it before showing up. In truth, the system they were askign about is a very different sort of animal than I was interviewing for. That system was an industrial automation project. Such projects are subject to extremely agressive timelines, and do not use accepted web application development practices. . . primarily because they have little to do with web development. The fact that I received the question seemed to me to betray a bit of naivete of the industrial automation world on the part of the interviewer. They definitely wanted me to talk about N-tier architecture, and though that project separated the database code from the application code, it is kind of unfair to even call it "code" because it is python typed into large text fields, giving the impression you're creating files, when in fact you are not.