ISRO CS 2015

Question 31

Semaphores are used to solve the problem of I. Race Condition II. Process Synchronization III. Mutual Exclusion IV. None of the above

• I and II
• II and III
• All of the above
• None of the above

Question 32

If there are 32 segments, each size 1 k bytes, then the logical address should have

• 13 bits
• 14 bits
• 15 bits
• 16 bits

Question 33

In a lottery scheduler with 40 tickets, how we will distribute the tickets among 4 processes and such that each process gets 10%, 5%, 60% and 25% respectively?

     P1   P2   P3   P4
a)   12   4    70   30
b)   7    5    20   10
c)   4    2    24   10
d)   8    5    40   30

• a
• b
• c
• d

Question 34

Suppose a system contains n processes and system uses the round-robin algorithm for CPU scheduling then which data structure is best suited for ready queue of the process

• stack
• queue
• circular queue
• tree

Question 35

A hard disk system has the following parameters : Number of tracks = 500 Number of sectors/track = 100 Number of bytes /sector = 500 Time taken by the head to move from one track to adjacent track = 1 ms Rotation speed = 600 rpm. What is the average time taken for transferring 250 bytes from the disk ?

• 300.5 ms
• 255.5 ms
• 255 ms
• 300 ms

Question 36

At a particular time of computation the value of a counting semaphore is 7. Then 20 P operations and 15 V operations were completed on this semaphore. The resulting value of the semaphore is :

• 42
• 2
• 7
• 12

Question 37

Increasing the RAM of a computer typically improves performance because:

• Virtual Memory increases
• Larger RAMs are faster
• Fewer page faults occur
• Fewer segmentation faults occur

Question 38

Consider the following program. main() { fork(); fork(); fork(); } How many new processes will be created?

• 8
• 6
• 7
• 5

Question 39

Suppose two jobs, each of which needs 10 minutes of CPU time, start simultaneously. Assume 50% I/O wait time. How long will it take for both to complete, if they run sequentially?

• 10
• 20
• 30
• 40

Question 40

If a node has K children in Btree, then the node contains exactly _____ keys.

• K²
• K - 1
• K + 1
• K^1/2