This question is from Operating System.

Suppose that a disk drive has 6,000 cylinders, numbered 0 to 5999. The drive is currently serving a request at cylinder 2350, and the previous request was at cylinder 1800. The queue of pending requests, in FIFO order, is: 2069, 1212, 3296, 2800, 244, 1618, 3856, 1523, 965, 3681 Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for SCAN and C-SCAN disk- scheduling algorithms? Show all the intermediate steps. Consider a disk drive with 10,000 cylinders. Suppose that 50 percent of the disk access requests are for a small set of cylinders between 100 and 800. Which of the following algorithms will take greater advantage of the given situation? Justify your answer. a) Shortest Seek Time First (SSTF) b) First Come First Serve (FCFS) Which of the following instructions should be privileged? Give reasons. a) Modify entries in the open-file table. b) Read the clock. c) Access I/O device.

8 Suppose that a disk drive has 6,000 cylinders, numbered 0 to 5999. The drive is currently serving a request at cylinder 2350, and the previous request was at cylinder 1800. The queue of pending requests, in FIFO order, is: 2069, 1212, 3296, 2800, 244, 1618, 3856, 1523, 965, 3681 Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for SCAN and C-SCAN disk- scheduling algorithms? Show all the intermediate steps. Consider a disk drive with 10,000 cylinders. Suppose that 50 percent of the disk access requests are for a small set of cylinders between 100 and 800. Which of the following algorithms will take greater advantage of the given situation? Justify your answer. 6 a) Shortest Seek Time First (SSTF) b) First Come First Serve (FCFS) Which of the following instructions should be privileged? Give reasons. 4. a) Modify entries in the open-file table. b) Read the clock. c) Access I/O device