I attended off campus drive. There are 6 colleges were participated including my college. The first round is rejection round with 27 questions. 11 from C aptitude, 9 from Data Structures and OS then 7 from Quantitative apptitude.
Then results are announced after 4 days. Next round is they asked to design a system for baby kid and that question contains problem definition, requirements, pre defined methods. Based on our solutions they shortlisted 6 students including me from whole crew.
Then there are normal two technical interview rounds and one personal interview. Technical interviews concentrated on OS concepts, OOPs concepts.
Interviewer asked me to draw flowchart for particular event performed by accelerometer sensor.
Please concentrate more on process synchronization in OS and solving real world problems. You should know basics and real time applications of OOPs and DS.