Sierraware interview questions

Written round: Section I: 1.How to find 2^x quickly? 2.How to find middle node in a linked list? 3.Explain bubble sort and merge sort.Which is better. 4.What are stack and heap data structures? 5.Explain use of Volatile keyword in C 6.What is a Mutex,Semaphore and a Spin Lock? 7.What is the execve system call? 8.How to declare and use function pointers in C? 9.What is BFS and DFS.Explain 10.How will you search for an integer in a sorted array Section II: 1.Write are malloc() and free() implemented in C? write an algorithm 2.write a fuction or macro to implement setbit, clearbit and togglebit operations to set,clear or toggle the 10th bit of a 32 bit integer. 3.Write a C program to implement Red Black tree 4.Write a C program to implement pipe 5.Write a C program to implement ring buffer 6.Write a C program to implement a Shell . 7.Write a C program to print all possible anagrams of a string First Technical Interview: In this round the interviewer saw my answer sheet and said that he was impressed with my answers in section I but he expected me to perform section II also well.So he asked me to write either the full code for a linked list or Binary search tree. I wrote the full code for a BST implementing all operations like insert,delete and search.He examined my code and asked me to explain it.I explained each module to him.But he told my code was full of recursive type and asked me to modify it to reduce stack size. Modified it by using a current pointer to point to root and update it suitably with some help from him Then he asked about my buffer allocation project and wat n all i remember in OS.i told him about paging,virtual memory......and when i said virtual memory he asked me wat is virtualization and to give an example about it.I told him about VMware manager and he told me like vmware they named their company as sierraware as such :P he asked me which OS i am comfortable with Asked me also if given offer when i can join nu He told that i l join on Aug :P He asked me why? I blabbered that i had booked my tickets to ma native he told that for freshers the salary wud be around 4L but working hours wer 12 hours and u need to study all the time to improve ur knowledge :P he finally told that i was put on waiting list and they will inform me soon about the results. Second Technical Interview: They called me again on 10th aug for another tech interview.This time i was interviewed by one of the Employees working there.He first asked me to write down a simple Hello World program in C and asked many questions regarding it. Then he moved on to my Final year project which i had done on CUDA and queried several questions regarding what is the aim,what was the problems that i faced in implementing the project.He also asked me to demonstrate parallelism in the multiplication of 123456 and 437123.I suggested by multiplying 123456 with each of the second number’s digits in 6 separate GPUs each. Simple code on Inorder traversal of a tree. What is the height of a balanced BST.He wanted a simple formula and explanation for that. An array of n numbers is given in which one of the numbers is repeated.Find that number. Finally i was escorted to the HR.He asked me to join from 16th august itself and introduced me to the 3 employees who were working there.Salary was 4lpa with some deduction on tax.Work was based on ARM systems development and Open Systems Virtualization.