The initial screening test took 2.5 hours. I felt like writing an exam.

Half of it was multiple-choice questions and trivial programming questions. The next half was more realistic programming questions. I did not have enough time to complete the final question in the second half of this test.

Nevertheless, they invited me in for an in-person interview. There were three guys in the interview asking general questions about programming, debugging, and networking.

I was not able to recall offhand what the typical flag is to pass to a common kernel function call.

The interview basically ended as soon as we talked about salary expectations. An interviewee should definitely research Glassdoor.com before talking to them.