Rank the disk scheduling algorithms (FCFS, SSTF, SCAN, and C-SCAN) in terms of their fairness in servicing a continuous stream of disk requests; order them from the most fair to the least fair. Consider a general stream of random disk requests, not a particular workload. (Verify your answer with reasons) OSSTF, SCAN, C-SCAN, FCFS O None of these O FCFS, SSTF, SCAN, C-SCAN OSCAN, C-SCAN, SSTF, FCFS Let's say the reference string is 04142434 2404142434 and we have 3 frames. By using clock algorithm the fault rate is . O 0.3 O 0.2 O 0.4 O 0.6 0.5

Suppose following sequence of disk track requests: 27, 129, 110, 186, 147, 41,10, 64, 120. Assume the disk head is initially positioned over track 100 and is moving in the direction of decreasing track number.a. Compare the disk scheduling algorithms with respect to the next accessed track and number of traversed tracks for FIFO, SSTF, SCAN and C-SCAN.b. What is the average seek length time for each of the algorithms?   PLEASE DO FOR FIFO, SSTF, SCAN and C-SCAN. NOT FOR C-LOOK. The previous answer you gave me was for C-LOOK. Thanks.

Requests are not usually uniformly distributed. For example, a cylinder containing the file system FAT or inodes can be expected to be accessed more frequently than a cylinder that only contains files. Suppose you know that 50 percent of the requests are for a small, fixed number of cylinders. a. Would any of the scheduling algorithms discussed in this chapter be particularly good for this case? Explain your answer. b. Propose a disk-scheduling algorithm that gives even better performance by taking advantage of this "hot spot" on the disk. c. File systems typically find data blocks via an indirection table, such as a FAT in DOS or inodes in UNIX. Describe one or more ways to take advantage of this indirection to improve the disk performance.