ISRO CS 2016

Question 41

At a particular time of computation the value of a counting semaphore is 7. Then 20 P operations and xV operations were completed on this semaphore. If the new value of semaphore is 5 ,x will be

• 18
• 22
• 15
• 13

Question 42

A system has 3 processes sharing 4 resources. If each process needs a maximum of 2 units, then

• Deadlock can never occur
• Deadlock may occur
• Deadlock has to occur
• None of these

Question 43

Determine the number of page faults when references to pages occur in the following order: 1, 2, 4, 5, 2, 1, 2, 4 Assume that the main memory can accommodate 3 pages and the main memory already has the pages 1 and 2, with page one having brought earlier than page 2. (LRU page replacement algorithm is used)

• 3
• 5
• 4
• None of these

Question 44

Working Set at an instant of time is

• the set of future references that the OS will make
• the set of future references that the OS will make in next unit of time
• the set of references with high frequency
• the set of pages that have been referenced in the last time units

Question 45

A CPU generates 32-bit virtual addresses. The page size is 4 KB. The processor has a translation look-aside buffer (TLB) which can hold a total of 128 page table entries and is 4-way set associative. The minimum size of the TLB tag is:

• 11 bits
• 13 bits
• 15 bits
• 20 bits

Question 46

For the real time operating system, which of the following is the most suitable scheduling scheme?

• Round robin
• Pre-emptive
• First come first serve
• Random scheduling

Question 47

In which one of the following page replacement policies, Belady\'s anomaly may occur?

• FIFO
• Optimal
• LRU
• MRU

Question 48

Consider the join of a relation R , with a relation S . If R has m number of tuples and S has n number of tuples then the maximum and minimum sizes of the join respectively are:

• m + n & 0

• mn & 0

• m + n & | m - n |

• mn & m + n

Question 49

Let R(a, b, c) and S(d, e, f) be two relations in which d is the foreign key of S that refers to the primary key of R. Consider the following four operations R and S. I. Insert into R II. Insert into S III. Delete from R IV. Delete from S Which of the following can cause violation of the referential integrity constraint above?

• Both I and IV
• Both II and III
• All of these
• None of these

Question 50

The relation book (title,price) contains the titles and prices of different books. Assuming that no two books have the same price, what does the following SQL query list? select title from book as B where (select count(*) from book as T where T.price>B.price)<5

• Titles of the four most expensive books
• Title of the fifth most inexpensive book
• Title of the fifth most expensive book
• Titles of the five most expensive books