One round of phone screening
3-4hrs of second round technical (on-site)
3-4 sessions, each sessions -> 40-60min
2-3 interviewers each session, multiple technical questions, but only fundamental questions
40% C programming
30% OS
20% TCP/IP network questions
10% behavior/previous experience
The interview was long, so most of the important knowledge points will be covered.
There is no weird questions, most questions are straightforward. Be careful on the details. Interviewer would judge based on your thinking process and your ability to deal with the details..