opeating-system-questions
I need to clearly answer these questions.
10.9 None of the disk-scheduling disciplines, except FCFS, is truly fair (starvation may occur).
a. Explain why this assertion is true.
b. Describe a way to modify algorithms such as SCAN to ensure fairness.
c. Explain why fairness is an important goal in a time-sharing system.
d. Give three or more examples of circumstances in which it is important that the operating system be unfair in serving I/O requests.
10.10 Explain why SSDs often use an FCFS disk-scheduling algorithm.
10.11 Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. The drive is currently serving a request at cylinder 2,150, and the previous request was at cylinder 1,805. The queue of pending requests, in FIFO order, is:
2,069, 1,212, 2,296, 2,800, 544, 1,618, 356, 1,523, 4,965, 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 each of the following disk-scheduling algorithms?
a. FCFS
‘b. SSTF
c. SCAN
d. LOOK
e. C-SCAN
f. C-LOOK
