[alphakappa]

I hope all interviewers are not like you. Not every web developer comes with a rigorous CS background. Some very excellent web developers I know come from various backgrounds and are good at what they do because they understand web development itself really well even though they may not know low level compiler and OS stuff.

It's always better to align the interview with the job (and future tasks they may be involved in), not some idealized CS background that you think everyone should have.

[burgerbrain]

I find it hard to believe that somebody with no knowledge of "low level compiler and OS stuff" that did know the basics of caching (generalized) and had strong problem solving skills (which all developers regardless of specialization should have) would have a hard time puzzling something approximating a correct diagnosis.

I think that you are not giving your average "web developer" enough credit.