Suppose that a disk drive has the cylinder numbered, 0 to 199 is currently serving a request at cylinder 143. The request queue is kept in the FIFO order 25, 17, 119, 197, 194, 15, 182, 115, and 183. What is the total head movement needed to satisfy these request for the following disk scheduling algorithm. a) FCFS b) SSTF [5]
2.
What is memory mapped I/O? Explain about device independent I/O software. [5]
Memory Management and File Systems
1.
Why Optimal Page Replacement is best but not practically feasible page replacement algorithm? Calculate the number of page faults for Optimal, LRU and FIFO replacement algorithm for the reference string: 1, 3, 4, 2, 3, 5, 4, 3, 1, 2, 4, 6, 3, 2, 1, 4, 2 using 3 page frames. [10]
2.
Why virtual memory technique is used in the computer system? What is logical address? Explain the process of conversion of logical address to physical address using TLB. [10]
3.
A 2 GB disk has a 4-KB block size, calculate the size of the file allocation table if each entry of the table is 4 bytes. [5]
4.
Write down the basic difference between coalescing and compaction with diagram. [5]
Process Management and Synchronization
1.
Find Average waiting time and turn-around time for following example using FIFO, SRTF and Round Robin scheduling algorithm. Assume quantum as 4 ms.