HP R & D Labs Interview Experience | Set 7 (For Experienced)

I would like to share my recent interview experience with HP R&D Labs banglore. I have experience of 4 years into network protocol development. The opening position is for network protocol developer (Layer2/Layer3). Selected people were called for the drive.
Totally, there are 5 rounds happened in a single day. (4 technical (1 written + 3 face to face), HR)

Written test (objective):
Questions in written test are to test the basic knowledge of C language and OS.
Mainly stressed on bitwise operators, little endian and big endian.

Technical Round 1:
This round is completely for c . Interviewer has asked question on bitwise operator and linked lists.
Memory layout of a c program.

1. How to set,unset and toggle bits using bitwise operators?
2. Stack implementation using linked lists?
3. Reversing of a linked list?
4. Memory layout of c program? How to findout the starting address of each segment (Data,stack,code)?

I could clear the first round and called for the second round.

Technical Round 2:
In this round, interviewer evaluated my knowledge in network protocols and the work, Operating systems and C.

After going through my resume, interviewer asked the protocol operations whichever i worked on and practical scenarios.

Mostly stressed on operating systems.

1. Difference between semaphore and mutex?
2. What are race conditions? How to avoid them?
3. What is a dead lock? how to detect it?
4. What flavours of operating system were used in your projects?
5. What are x-factors of these operating systems?

In C,
1. Swap two nodes of a linked list(not data)?
2. Malloc to allocate memory for 2-D array?
3.

int main() {
        chat *p=NULL;
        p++;
        printf("%d",p);
    }

Output of the above program?
4. What is a NULL pointer crash? how to detect it?
5. How memory leaks happen? how to find out them?

Technical Round 3 (Manager+technical):

This round was taken by the manager. He tried to test everything from C basics, networking, operating systems and software methodologies. And as expected, other questions from manager.

HR round:
This is the final round. Just a casual discussion happened regarding the notice period, hr questions, salary negotiations etc.