GATE IT 2006

Question 11

In the working-set strategy, which of the following is done by the operating system to prevent thrashing?

1. It initiates another process if there are enough extra frames.
2. It selects a process to suspend if the sum of the sizes of the working-sets exceeds the total number of available frames.

• I only
• II only
• Neither I nor II
• Both I and II

Question 12

The process state transition diagram of an operating system is as given below.

Which of the following must be FALSE about the above operating system?

• It is a multiprogrammed operating system
• It uses preemptive scheduling
• It uses non-preemptive scheduling
• It is a multi-user operating system

Question 13

Consider the relations r₁(P, Q, R) and r₂(R, S, T) with primary keys P and R respectively. The relation r₁ contains 2000 tuples and r₂ contains 2500 tuples. The maximum size of the join r₁⋈ r₂ is :  

• 2000
• 2500
• 4500
• 5000

Question 14

Which of the following relational query languages have the same expressive power?

1. Relational algebra
2. Tuple relational calculus restricted to safe expressions
3. Domain relational calculus restricted to safe expressions

• II and III only

• I and II only

• I and III only

• I, II and III

Question 15

The cyclomatic complexity of the flow graph of a program provides  

• an upper bound for the number of tests that must be conducted to ensure that all statements have been executed at most once

• a lower bound for the number of tests that must be conducted to ensure that all statements have been executed at most once

• an upper bound for the number of tests that must be conducted to ensure that all statements have been executed at least once

• a lower bound for the number of tests that must be conducted to ensure that all statements have been executed at least once

Question 16

With respect to software testing, consider a flow graph G with one connected component. Let E be the number of edges, N be the number of nodes, and P be the number of predicate nodes of G. Consider the following four expressions:

1. E - N + P
2. E - N + 2
3. P +  2
4. P + 1

The cyclomatic complexity of G is given by

• I or III
• II or III
• II or IV
• I or IV

Question 17

HELO and PORT, respectively, are commands from the protocols  

• FTP and HTTP
• TELNET and POP3
• HTTP and TELNET
• SMTP and FTP

Question 18

Which of the following statements is TRUE?  

• Both Ethernet frame and IP packet include checksum fields
• Ethernet frame includes a checksum field and IP packet includes a CRC field
• Ethernet frame includes a CRC field and IP packet includes a checksum field
• Both Ethernet frame and IP packet include CRC fields

Question 19

Which of the following statement(s) is TRUE?

1. A hash function takes a message of arbitrary length and generates a fixed length code.
2. A hash function takes a message of fixed length and generates a code of variable length.
3. A hash function may give the same hash value for distinct messages.

• I only

• II and III only

• I and III only

• II only

Question 20

Consider the following first order logic formula in which R is a binary relation symbol. ∀x∀y (R(x, y)  => R(y, x)) The formula is  

• satisfiable and valid
• satisfiable and so is its negation
• unsatisfiable but its negation is valid
• satisfiable but its negation is unsatisfiable