Atos Graduate Trainee Engineer interview questions

aptitude test(logical,maths ,quants,grammer) technical (The interview round was a bit tricky. They asked me about the general OOPS concept, then they switched to OS, there were questions such as what is cache, multi-core architecture, multi programming, the difference between process and thread, explain thread in detail. They asked me basic DBMS questions such as how to write update queries, also they asked me to write a C or C++ program on reversing a string which was quite easy. ( Be clear with entire logic) . Also one question on how to insert an element at a specific position in the array ( what will be the logic for this). Then they asked me about HTML. The basic tags. What is an iframe tag? What is the syntax of img tag? The difference between <tr> <td> <th> tag. Which tag doesn’t require closing tag etc.) hr round