NVIDIA Systems Programmer interview questions

I had 3 telephone rounds. First interview is about job decription and attitude round. They described some situation and How I would react to them etc. Mostly about intra-office issues. The next two were Technical rounds. The focus of second round is on Operating systems fundamentals and C/C++. The foucs of third round is on programming. Asked simple programming questions and asked me to explaing the code over the telephone. I cleared these rounds. Then they invited me to onsite. I was asked to take a test on C/C++, OS, DS and aptitude. I had two more rounds of face to face interviews. They concentrated on my math skills like probability etc