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b. Compare the memory organization schemes of contiguous memory allocation, pure

segmentation, and pure paging with respect to thefollowing issues:

i. External fragmentation
11. Internal fragmentation (6) iii. Ability to share code across processes
18. a. What is the advantage of indexed allocation of disk space? (5)

b. What is an inode in UNIX? Consider a file system that uses inodes to represent
files. Disk blocks are 8 KB in size, and a pointer to a disk block requires 4 bytes.
This file system has 12 direct disk blocks, as well as single, double, and triple
indirect disk blocks. What is the maximum size of a file that can be stored in this
file system? (5)

19. a. The disk-scheduling algorithm should be written as a separate module of the

operating system. Why? (4)

b. Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4,999. The drive is
currently serving arequest at cylinder 2,150, and the previous request was at
cylinder 1,805. The queue of pendingrequests, in FIFO order, is:2,069, 1,212,
2,296, 2,800, 544, 1,618, 356, 1,523, 4,965, 3,681
Starting from the current head position, what is the total distance (in cylinders) that
the disk arm movesto satisfy all the pending requests for each of the following
disk-scheduling algorithms? (6)
i) FCFS ii) SSTF 111) SCAN

20. a. Define the terms i) Seek time ii) Rotational delay iii) Disk bandwidth. (3) b. Explain

how access matrix is used as a protection mechanism. (7)

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