U.G.C. NET Exam. December 2023 Paper II (COMPUTER SCIENCE)

Total Questions: 100

51. Which of the following statements is/are NOT CORRECT about NUMA?

(A) LOAD and STORE instructions are used to access remote memory.
(B) There is a single address space visible to all CPU.
(C) Access to local memory is slower than access to remote memory.
(D) When the access time to remote memory is hidden, the system is called NC - NUMA.
(E) In CC - NUMA, Coherent caches are present.
Choose the correct answer from the options given below :

Correct Answer: (d) (C) and (D) Only
Solution:

Non-Uniform Memory Access (NUMA) is a computer memory design used in multiprocessing. where the memory access time depends or the memory location relative to the processor. under NUMA, a processor can access its own local memory faster than non-local memory. In NC-NUMA systems, remote memory access times are not hidden by cache mechanisms. So, if the access time to remote memory is not hidden, the system is called NC- NUMA. Thus, the statements (c) and (d) are not correct.

52. Indexed/grouped allocation is useful as:

(A) It supports both sequential and direct access.
(B) Entire block is available for data.
(C) It does not require lots of space for keeping pointers.
(D) No external fragmentation.
Choose the correct answer from the options given below.

Correct Answer: (d) (A), (B) and (D) Only
Solution:

Indexed/grouped allocation typically supports both sequential and direct access. Entire block is available for data. It helps prevent external fragmentation as all files have their own index block that keeps track of the blocks associated with it. Indexed allocation actually needs space to store pointers in the index block for each file.

53. Which of the following statements are CORRECT?

(A) A process always check state of currently executing process to enter critical schema.
(B) Spin locks uses busy waiting.
(C) Periodically testing a variable until some value appear is known as busy waiting.
(D) Critical region is a part of program, where shared memory is kept.
(E) Printer daemon, continuously checks to see if there are any file to be printed.
Choose the correct answer from the options given below:

Correct Answer: (c) (B) and (D) Only
Solution:

(A) A process does not always need to check the state of the currently executing process to enter the critical section.
(B) Spin locks uses busy waiting.
(C) Busy waiting, also known as spinning, is a technique where a process continuously checks for a condition to be true in a tight loop, without yielding the CPU to other processes.
(d) Critical region is a part of program, where shared memory is kept.

54. Three address codes can be represented in special structures known as:

(A) Quadruples
(B) Triples
(C) Patterns
(D) Indirect Triples
Choose the correct answer from the options given below:

Correct Answer: (b) (A), (B) and (D) Only
Solution:

Three address codes can be represented in special structures known as.
1. Quadruples – Quadruples are a type of three address code representation. They consist of four field: operator, operand 1, operands2, and result.
2. Triples– Triples are another form of three address code representation. They consist of three fields: operator, operand1, and operand2.
3. Indirect Triples– indirect triples are similar to triples but with an added feature of indirect addressing. In indirect triples, the operands can be memory location instead of just values. Patterns and other structures and not typically used to represent three address codes in compilers.

55. Which of the statement is/are CORRECT?

(A) Moore and Mealy machines are finite state machines with output capabilities.
(B) Any given Moore machine has an equivalent Mealy machine.
(C) Any given Mealy machine has an equivalent Moore machine.
(D) Moore machine is not a finite state machine.
Choose the correct answer form the options given below :

Correct Answer: (b) (A), (B) and (C) Only
Solution:

Let's break down each statements-
(A) Moore and Mealy machines are finite state machine with output capabilities. This statement is correct, Both Moore and Mealy machine are types of finite state machine that have the ability to produce output based on their current state.
(B) Any given Moore machine has an Equivalent Mealy machine. This statement is correct. It's possible to correct to convert any Moore machine into an equivalent Mealy machine.
(C) Any given Mealy machine has an equivalent Moore machine. This statement is incorrect. Unlike converting from Moore to Mealy. It's not always possible to convert a Mealy machine into an equivalent Moore machine.
(D) Moore machine is not a finite state machine. This statement is incorrect. Moore machines are indeed a type of finite state machine.
So, the correct answer is (b).

56. The statement P(x): "x = x² ", If the universe of disclosure consists of integers, what are the following have truth values:

(A) P(0)
(B) P(1)
(C) P(2)
(D) ∃x P(x)
(E) ∀x P(x)
Choose the correct answer form the options given below:

Correct Answer: (c) (A), (B) and (D) Only
Solution:

Let's evaluate each of the options-
(A)- P(0)- Substituting 0 for x, we get 0 = 0² , which is true. So, P(0) is true.
(B) P(1)- Substituting 1 for x, we get 1 = 1² , which is true. So, P(2) is true.
(C) P(2)- Substituting 2 for x we get 2 = 2² .Which is false. So, P(2) is false.
(D) ∃x P(x)- This statement means ''There exits an integer x such that x = x² . ''Since this is not true for any integer except 0 and 1, This statements is false.
(E) ∀x P(x)- This statement ''for all integer x, x = x² . ''Since this is only true for x = 0 and 1, and false for all other integer, this statement is false.
So, the correct option is (c).

57. Which of the following statement are truth statements if universe of disclosure is set of integers:

(A) ∀n (n² ≥0)
(B) ∃n (n² = 2)
(C) ∀n (n² ≥ n)
(D) ∃n (n² < 0)
Choose the correct answer from the options given below :

Correct Answer: (d) (A) and (C) Only
Solution:

58. Which of the following graphs are trees?


Correct Answer: (a) (A) and (B) Only
Solution:

In graph Theory a tree is a type of undirected graph where any two vertices are connected by exactly one path.
Trees have several properties
1. Connected, Every pair of vertices in a tree is connected by a unique path.
2. Acyclic A true has no cycles or loops. Adding any edge to a tree would Create a cycle.
3. N–1 Edges and
4. Maximally Acyclic.
So A and B graphs trees.

59. Which of the following are example of CSMA channel sensing methods?

(A) 1-persistent
(B) 2-persistent
(C) p-persistent
(D) o-persistent
Choose the correct answer from the options given below:

Correct Answer: (b) (A), (C) and (D) Only
Solution:

CSMA (Carrier Sense Multiple Access) has different access methods- including.
1. 1- persistent CSMA
2. Non- persistent CSMA
3. P - Persistent CSMA
4. Q- persistent CSMA

60. The selection of Spiral Model based on characteristics of requirements:

(A) Are requirements easily understandable and defined?
(B) Do we change requirements quite often?
(C) Can we define requirements early in the cycle?
(D) Requirements are indicating a complex to be built
Choose the correct answer from the options given below :

Correct Answer: (c) (B) and (D) Only
Solution:

The spiral Model in software development is a risk. driven model which involves four phases, planning, risk analysis, engineering and evaluation. This model is ideal for large. complex and innovation projects where the requirement might not be clearly defined up front or are highly likely to evolve during the course of the project.
(2) Do we change requirements quite often? This indeed aligns with the spiral model as changes can be introduced in the system in the subsequent phases, making it highly flexible. (4) Requirements are indicating a complex to be built spiral model is suitable for conflux projects are the risk analysis phase allows for identification and mitigation of any potential issues, especially important in a complex project.