UGC NET CS 2015 Dec - II

Question 21

Which of the following fields in IPV₄ datagram is not related to fragmentation?

• Type of service
• Fragment offset
• Flags
• Identification

Question 22

In a typical mobile phone system with hexagonal cells, it is forbidden to reuse a frequency band in adjacent cells. If 840 frequencies are available, how many can be used in a given cell?

• 280
• 110
• 140
• 120

Question 23

Using p = 3, q = 13, d = 7 and e = 3 in the RSA algorithm, what is the value of ciphertext for a plain text 5 ?

• 8
• 16
• 26
• 33

Question 24

A virtual memory has a page size of 1K words. There are eight pages and four blocks. The associative memory page table contains the following entries: Which of the following list of virtual addresses (in decimal) will not cause any page fault if referenced by the CPU ?

• 1024, 3072, 4096, 6144
• 1234, 4012, 5000, 6200
• 1020, 3012, 6120, 8100
• 2021, 4050, 5112, 7100

Question 25

Suppose that the number of instructions executed between page fault is directly proportional to the number of page frames allocated to a program. If the available memory is doubled, the mean interval between page faults is also doubled. Further, consider that a normal instruction takes one microsecond, but if a page fault occurs, it takes 2001 microseconds. If a program takes 60 sec to run, during which time it gets 15,000 page faults, how long would it take to run if twice as much memory were available?

• 60 sec
• 30 sec
• 45 sec
• 10 sec

Question 26

Consider a disk with 16384 bytes per track having a rotation time of 16 msec and average seek time of 40 msec. What is the time in msec to read a block of 1024 bytes from this disk?

• 57 sec
• 49 sec
• 48 sec
• 17 sec

Question 27

A system has four processes and five allocatable resources. The current allocation and maximum needs are as follows:

	        Allocated	Maximum	       Available
Process A	1 0 2 1 1	1 1 2 1 3	0 0 x 1 1
Process B	2 0 1 1 0	2 2 2 1 0	
Process C	1 1 0 1 0	2 1 3 1 0	
Process D	1 1 1 1 0	1 1 2 2 1	
The smallest value of x for which the above system in safe state is __________.

• 1
• 3
• 2
• Not safe for any value of x.

Question 28

In Unix, the login prompt can be changed by changing the contents of the file __________.

• crontab

• init

• gettydefs

• inittab

Question 29

A data cube C, has n dimensions, and each dimension has exactly p distinct values in the base cuboid. Assume that there are no concept hierarchies associated with the dimensions. What is the maximum number of cells possible in the data cube, C?

• pⁿ
• p
• (2ⁿ - 1)p+1
• (p + 1)ⁿ

Question 30

Suppose that from given statistics, it is known that meningitis causes stiff neck 50% of the time, that the proportion of persons having meningitis is 1 / 50000 , and that the proportion of people having stiff neck is 1 / 20. Then the percentage of people who had meningitis and complain about stiff neck is:

• 0.01%
• 0.02%
• 0.04%
• 0.05%