11. Define the terms virtual memory and page fault. 12. Show the memory layout of a multiprogramming system with an appropriate diagram. 13. Define the terms swapping, paging, and segmentation  14. Briefly describe the sequential and random file access mechanisms. 15. What is fragmentation? Show the compaction process with a diagram. 16. Write the difference between deadlock and starvation  17. Describe the necessary condition of deadlock. 18. Write and explain the resource request algorithm