Turing Prep | Previous Year Questions

Question : 1

The man who is now Municipal Commissioner worked as ____________________.

the security guard at a university

a security guard at the university

a security guard at university

the security guard at the university

Correct Answer : B

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 2

Nobody knows how the Indian cricket team is going to cope with the difficult and seamer-friendly wickets in Australia.

Choose the option which is closest in meaning to the underlined phrase in the above sentence.

put up with

put in with

put down to

put up against

Correct Answer : A

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 3

Find the odd one in the following group of words.

mock, deride, praise, jeer

mock

deride

praise

jeer

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 4

Pick the odd one from the following options.

CADBE

JHKIL

XVYWZ

ONPMQ

Correct Answer : D

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 5

In a quadratic function, the value of the product of the roots (α, β) is 4. Find the value of

\(\dfrac{\alpha^{n}+\beta^{n}}{\alpha^{-n}+\beta^{-n}}\)

\(n^4\)

\(4^n\)

\(2^{2n-1}\)

\(4^{n-1}\)

Correct Answer : B

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 6

Among 150 faculty members in an institute, 55 are connected with each other through Facebook^® and 85 are connected through WhatsApp^®. 30 faculty members do not have Facebook^® or WhatsApp^® accounts. The number of faculty members connected only through Facebook^® accounts is ______________.

35

45

65

90

Correct Answer : A

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 7

Computers were invented for performing only high-end useful computations. However, it is no understatement that they have taken over our world today. The internet, for example, is ubiquitous. Many believe that the internet itself is an unintended consequence of the original invention. With the advent of mobile computing on our phones, a whole new dimension is now enabled. One is left wondering if all these developments are good or, more importantly, required.

Which of the statement(s) below is/are logically valid and can be inferred from the above paragraph?

(i) The author believes that computers are not good for us.

(ii) Mobile computers and the internet are both intended inventions

(i) only

(ii) only

both (i) and (ii)

neither (i) nor (ii)

Correct Answer : D

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 8

All hill-stations have a lake. Ooty has two lakes.

Which of the statement(s) below is/are logically valid and can be inferred from the above sentences?

(i) Ooty is not a hill-station.

(ii) No hill-station can have more than one lake.

(i) only

(ii) only

both (i) and (ii)

neither (i) nor (ii)

Correct Answer : D

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 9

In a 2 × 4 rectangle grid shown below, each cell is a rectangle. How many rectangles can be observed in the grid?

21

27

30

36

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 10

Choose the correct expression for \(f(x)\) given in the graph.

\(𝑓(𝑥) = 1 − |𝑥 − 1|\)

\(𝑓(𝑥) = 1 + |𝑥 − 1| \)

\(𝑓(𝑥) = 2 − |𝑥 − 1| \)

\(𝑓(𝑥) = 2 + |𝑥 − 1| \)

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 11

Consider the following expressions:

(i) \(false\)

(ii) \(Q\)

(iii) \(true\)

(iv) \(P∨Q\)

(v) \(¬Q∨P\)

The number of expressions given above that are logically implied by \(P ∧ (P ⇒ Q)\) is .

Correct Answer : 4

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 12

Let \(f(x)\) be a polynomial and \(g(x)=f'(x)\) be its derivative. If the degree of \((f(x)+f(-x))\) is 10, then the degree of \((g(x) - g(-x))\) is ________ .

Correct Answer : 9

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 13

The minimum number of colours that is sufficient to vertex-colour any planar graph is _____________ .

Correct Answer : 4

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 14

Consider the systems, each consisting of m linear equations in n variables.

I. If \(m < n\), then all such systems have a solution

II. If \(m > n\), then none of these systems has a solution

III. If \(m = n\), then there exists a system which has a solution

Which one of the following is CORRECT?

I, II and III are true

Only II and III are true

Only III is true

None of them is true

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 15

Suppose that a shop has an equal number of LED bulbs of two different types. The probability of an LED bulb lasting more than 100 hours given that it is of Type 1 is 0.7, and given that it is of Type 2 is 0.4. The probability that an LED bulb chosen uniformly at random lasts more than 100 hours is ____________ .

Correct Answer : 0.55

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 16

Suppose that the eigenvalues of matrix A are 1,2,4. The determinant of (A⁻¹ )^T is _____________ .

Correct Answer : 0.124 to 0.126

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 17

Consider an eight-bit ripple-carry adder for computing the sum of A and B, where A and B are integers represented in 2’s complement form. If the decimal value of A is one, the decimal value of B that leads to the longest latency for the sum to stabilize is _________________ .

Correct Answer : -1

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 18

Let, \(x_1⊕x_2⊕x_3⊕x_4 = 0\) where \(x_1, x_2, x_3, x_4\) are Boolean variables, and ⊕ is the XOR operator. Which one of the following must always be TRUE?

\(x_1x_2x_3x_4 = 0\)

\(x_1x_3 +x_2 = 0\)

\(\overline x_1 ⊕ \overline x_3 = \overline x_2 ⊕ \overline x_4\)

\(x_1 +x_2 +x_3 +x_4 = 0\)

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 19

Let \(X\) be the number of distinct 16-bit integers in 2’s complement representation. Let \(Y\) be the number of distinct 16-bit integers in sign magnitude representation.

Then \(X −Y\) is ____________ .

Correct Answer : 1

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 20

A processor has 40 distinct instructions and 24 general purpose registers. A 32-bit instruction word has an opcode, two register operands and an immediate operand. The number of bits available for the immediate operand field is __________________ .

Correct Answer : 16

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 21

Breadth First Search (BFS) is started on a binary tree beginning from the root vertex. There is a vertex \(t\) at a distance four from the root. If t is the \(n\)-th vertex in this BFS traversal, then the maximum possible value of \(n\) is _____________ .

Correct Answer : 31

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 22

The value printed by the following program is __________________ .


    void f (int * p, int m) { 

           m = m + 5; 

          *p = *p + m; 

           return; 

      }  



      void main () { 

       int i=5, j=10; 



       f (&i, j); 

       printf ("%d", i+j); 

     }

Correct Answer : 30

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 23

Assume that the algorithms considered here sort the input sequences in ascending order. If the input is already in ascending order, which of the following are TRUE?

I. Quicksort runs in \(Θ(n^2)\) time

II. Bubblesort runs in \(Θ(n^2)\) time

III. Mergesort runs in \(Θ(n)\) time

IV. Insertion sort runs in \(Θ(n)\) time

I and II only

I and III only

II and IV only

I and IV only

Correct Answer : D

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 24

The Floyd-Warshall algorithm for all-pair shortest paths computation is based on

Greedy paradigm.

Divide-and-Conquer paradigm.

Dynamic Programming paradigm.

neither Greedy nor Divide-and-Conquer nor Dynamic Programming paradigm.

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 25

\(N\) items are stored in a sorted doubly linked list. For a \(delete\) operation, a pointer is provided to the record to be deleted. For a \(decrease-key\) operation, a pointer is provided to the record on which the operation is to be performed.

An algorithm performs the following operations on the list in this order: \(Θ(N)\) \(delete\), \(O(logN)\) \(insert\), \(O(logN)\) \(find\), and \(Θ(N)\) \(decrease-key\). What is the time complexity of all these operations put together?

\(O(log^2N)\)

\(O(N)\)

\(O(N^2) \)

\(Θ(N^2logN)\)

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 26

The number of states in the minimum sized DFA that accepts the language defined by the regular expression

\((0+1)^∗ (0+1)(0+1)^∗\)

is ___________ .

Correct Answer : 2

Question Type : NAT

Max Marks : 1

Negative Marks : 0

Question : 27

Language \(L_1\) is defined by the grammar: \(S_1 → aS_1b|ε\)

Language \(L_2\) is defined by the grammar: \(S_2 → abS_2|ε\)

Consider the following statements:

\(P\): \(L_1\) is regular

\(Q\): \(L_2\) is regular

Which one of the following is TRUE?

Both \(P\) and \(Q\) are true

\(P\) is true and \(Q\) is false

\(P\) is false and \(Q\) is true

Both \(P\) and \(Q\) are false

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 28

Consider the following types of languages: \(L_1\) : Regular, \(L_2\) : Context-free, \(L_3\) : Recursive, \(L_4\) : Recursively enumerable. Which of the following is/are TRUE?

I. \(\overline L_3 \cup L_4\) is recursively enumerable

II. \(L_2 \cup L_3\) is recursive

III. \(L_1^* \cup L_2\) is context-free

IV. \(L_1 \cup \overline L_2\) is context-free

I only

I and III only

I and IV only

I, II and III only

Correct Answer : D

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 29

Match the following:

(P) Lexical analysis	(i) Leftmost derivation
(Q) Top down parsing	(ii) Type checking
(R) Semantic analysis	(iii) Regular expressions
(S) Runtime environments	(iv) Activation records

P ↔ i, Q ↔ ii, R ↔ iv, S ↔ iii

P ↔ iii, Q ↔ i, R ↔ ii, S ↔ iv

P ↔ ii, Q ↔ iii, R ↔ i, S ↔ iv

P ↔ iv, Q ↔ i, R ↔ ii, S ↔ iii

Correct Answer : B

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 30

In which one of the following page replacement algorithms it is possible for the page fault rate to increase even when the number of allocated frames increases?

LRU (Least Recently Used)

OPT (Optimal Page Replacement)

MRU (Most Recently Used)

FIFO (First In First Out)

Correct Answer : D

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 31

B+ Trees are considered BALANCED because

the lengths of the paths from the root to all leaf nodes are all equal.

the lengths of the paths from the root to all leaf nodes differ from each other by at most 1.

the number of children of any two non-leaf sibling nodes differ by at most 1.

the number of records in any two leaf nodes differ by at most 1.

Correct Answer : A

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 32

Suppose a database schedule S involves transactions \(T_1, ..., T_n\). Construct the precedence graph of \(S\) with vertices representing the transactions and edges representing the conflicts. If \(S\) is serializable, which one of the following orderings of the vertices of the precedence graph is guaranteed to yield a serial schedule?

Topological order

Depth-first order

Breadth-first order

Ascending order of transaction indices

Correct Answer : A

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 33

Anarkali digitally signs a message and sends it to Salim. Verification of the signature by Salim requires

Anarkali’s public key.

Salim’s public key.

Salim’s private key

Anarkali’s private key.

Correct Answer : A

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 34

In an Ethernet local area network, which one of the following statements is TRUE?

A station stops to sense the channel once it starts transmitting a frame.

The purpose of the jamming signal is to pad the frames that are smaller than the minimum frame size.

A station continues to transmit the packet even after the collision is detected.

The exponential backoff mechanism reduces the probability of collision on retransmissions.

Correct Answer : D

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 35

Identify the correct sequence in which the following packets are transmitted on the network by a host when a browser requests a webpage from a remote server, assuming that the host has just been restarted.

HTTP GET request, DNS query, TCP SYN

DNS query, HTTP GET request, TCP SYN

DNS query, TCP SYN, HTTP GET request

TCP SYN, DNS query, HTTP GET request

Correct Answer : C

Question Type : MCQ

Max Marks : 1

Negative Marks : 0.33

Question : 36

A binary relation \(R\) on \(\mathbb{N} \times \mathbb{N}\) is defined as follows: \((a, b) R(c, d)\) if \(a \leq c\) or \(b \leq d\). Consider the following propositions:

P: \(R\) is reflexive

Q: \(R\) is transitive

Which one of the following statements is TRUE?

Both P and Q are true.

P is true and Q is false.

P is false and Q is true.

Both P and Q are false.

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 37

Which one of the following well-formed formulae in predicate calculus is NOT valid?

\((∀x p(x) ⇒ ∀x q(x)) ⇒ (∃x¬p(x) ∨ ∀x q(x))\)

\((∃x p(x) ∨ ∃x q(x)) ⇒ ∃x (p(x) ∨ q(x))\)

\(∃x (p(x) ∧ q(x)) ⇒ (∃x p(x) ∧ ∃x q(x))\)

\(∀x (p(x) ∨ q(x)) ⇒ (∀x p(x) ∨ ∀x q(x)) \)

Correct Answer : D

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 38

Consider a set \(U\) of 23 different compounds in a Chemistry lab. There is a subset \(S\) of \(U\) of 9 compounds, each of which reacts with exactly 3 compounds of \(U\). Consider the following statements:

I. Each compound in \(U \setminus S \) reacts with an odd number of compounds.

II. At least one compound in \(U \setminus S \) reacts with an odd number of compounds.

III. Each compound in \(U \setminus S \) reacts with an even number of compounds.

Which one of the above statements is ALWAYS TRUE?

Only I

Only II

Only III

None

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 39

The value of the expression 13⁹⁹(mod 17), in the range 0 to 16, is __________ .

Correct Answer : 4

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 40

Suppose the functions \(F\) and \(G\) can be computed in 5 and 3 nanoseconds by functional units \(U_F\) and \(U_G\), respectively. Given two instances of \(U_F\) and two instances of \(U_G\), it is required to implement the computation \(F(G(X_i)) \) for \(1 ≤ i ≤ 10\). Ignoring all other delays, the minimum time required to complete this computation is _____________ nanoseconds.

Correct Answer : 28

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 41

Consider a processor with 64 registers and an instruction set of size twelve. Each instruction has five distinct fields, namely, opcode, two source register identifiers, one destination register identifier, and a twelve-bit immediate value. Each instruction must be stored in memory in a byte-aligned fashion. If a program has 100 instructions, the amount of memory (in bytes) consumed by the program text is __________ .

Correct Answer : 500

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 42

The width of the physical address on a machine is 40 bits. The width of the tag field in a 512 KB 8-way set associative cache is _________ bits.

Correct Answer : 24

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 43

Consider a 3 GHz (gigahertz) processor with a three-stage pipeline and stage latencies \(τ_1, τ_2\), and \(τ_3\) such that \(τ_1 = 3τ_2/4 = 2τ_3\). If the longest pipeline stage is split into two pipeline stages of equal latency, the new frequency is ___________ GHz, ignoring delays in the pipeline registers.

Correct Answer : 3.9 to 4.1

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 44

A complete binary min-heap is made by including each integer in [1,1023] exactly once. The depth of a node in the heap is the length of the path from the root of the heap to that node. Thus, the root is at depth 0. The maximum depth at which integer 9 can appear is _________ .

Correct Answer : 8

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 45

The following function computes X^Y for positive integers X and Y.


int exp (int X, int Y) { 

     int res =1, a = X, b = Y;

   

     while (b != 0) { 

         if (b % 2 == 0) {a = a * a; b = b/2; } 

         else         {res = res * a; b = b - 1; } 

     } 

     return res; 

}

Which one of the following conditions is TRUE before every iteration of the loop?

X^Y = a^b

(res ∗ a)^Y = (res ∗ X)^b

X^Y = res ∗ a^b

X^Y = (res ∗ a)^b

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 46

Consider the following New-order strategy for traversing a binary tree:

Visit the root;
Visit the right subtree using New-order;
Visit the left subtree using New-order;

The New-order traversal of the expression tree corresponding to the reverse polish expression 3 4 * 5 - 2 ˆ 6 7 * 1 + - is given by:

+ - 1 6 7 * 2 ˆ 5 - 3 4 *

- + 1 * 6 7 ˆ 2 - 5 * 3 4

- + 1 * 7 6 ˆ 2 - 5 * 4 3

1 7 6 * + 2 5 4 3 * - ˆ -

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 47

Consider the following program:


int f (int * p, int n) 

{ 

    if (n <= 1) return 0; 

    else return max (f (p+1, n-1), p[0] - p[1]); 

}

 int main () 

{

    int a[] = {3, 5, 2, 6, 4}; 

    printf(" %d", f(a, 5)); 

}

Note: max(x,y) returns the maximum of x and y.

The value printed by this program is .

Correct Answer : 3

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 48

Let \(A_1,A_2,A_3\), and A4 be four matrices of dimensions 10 × 5,5 × 20,20 × 10, and 10 × 5, respectively. The minimum number of scalar multiplications required to find the product \(A_1A_2A_3A_4\) using the basic matrix multiplication method is .

Correct Answer : 1500

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 49

The given diagram shows the flowchart for a recursive function \(A(n)\). Assume that all statements, except for the recursive calls, have \(O(1)\) time complexity. If the worst case time complexity of this function is \(O(n^α )\), then the least possible value (accurate up to two decimal positions) of \(α\) is ____________ .

Correct Answer : 2.2 to 2.4

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 50

The number of ways in which the numbers 1, 2, 3, 4, 5, 6, 7 can be inserted in an empty binary search tree, such that the resulting tree has height 6, is ____________ .

Note: The height of a tree with a single node is 0.

Correct Answer : 64

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 51

In an adjacency list representation of an undirected simple graph \(G = (V,E)\), each edge \((u, v)\) has two adjacency list entries: [\(v\)] in the adjacency list of \(u\), and [\(u\)] in the adjacency list of \(v\). These are called twins of each other. A twin pointer is a pointer from an adjacency list entry to its twin. If |\(E\)| = \(m\) and |\(V\)| = \(n\), and the memory size is not a constraint, what is the time complexity of the most efficient algorithm to set the twin pointer in each entry in each adjacency list?

\(Θ(n^2)\)

\(Θ(n+m) \)

\(Θ(m^2)\)

\(Θ(n^4)\)

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 52

Consider the following two statements:

I. If all states of an NFA are accepting states then the language accepted by the NFA is \(Σ^∗\) .

II. There exists a regular language \(A\) such that for all languages \(B\), \(A \cap B\) is regular.

Which one of the following is CORRECT?

Only I is true

Only II is true

Both I and II are true

Both I and II are false

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 53

Consider the following languages:

\(L_1 = {a^n b^m c^{n+m} : m,n ≥ 1}\)

\(L_2 = {a^n b^n c^{2n} : n ≥ 1}\)

Which one of the following is TRUE?

Both \(L_1\) and \(L_2\) are context-free.

\(L_1\) is context-free while \(L_2\) is not context-free.

\(L_2\) is context-free while \(L_1\) is not context-free.

Neither \(L_1\) nor \(L_2\) is context-free.

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 54

Consider the following languages.

\(L_{1} = \left\{\left\langle M \right\rangle \mid M \text{ takes at least 2016 steps on some input} \right\}\)

\(L_{2} = \left\{\left\langle M \right\rangle \mid M \text { takes at least 2016 steps on all inputs} \right\}\)

\(L_{3} = \left\{\left\langle M \right\rangle \mid M \ \text {accepts }\epsilon\right\}\)

where for each Turing machine \(M\), \(M, \left\langle M \right\rangle\) denotes a specific encoding of \(M\). Which one of the following is TRUE?

\(L_1\) is recursive and \(L_2,L_3\) are not recursive

\(L_2\) is recursive and \(L_1,L_3\) are not recursive

\(L_1,L_2\) are recursive and \(L_3\) is not recursive

\(L_1,L_2,L_3\) are recursive

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 55

Which one of the following grammars is free from left recursion?

S → AB

A → Aa | b

B → c

S → Ab | Bb | c

A → Bd | ε

B → e

S → Aa | B

A → Bb | Sc | ε

B → d

S → Aa | Bb | c

A → Bd | ε

B → Ae | ε

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 56

A student wrote two context-free grammars G1 and G2 for generating a single C-like array declaration. The dimension of the array is at least one. For example,

int a[10] [3];

The grammars use D as the start symbol, and use six terminal symbols int ; id [ ] num.

Grammar G1	Grammar G2
D → intL;	D → intL;
L → id[E	L → idE
E → num]	E → E[num]
E → num][E	E → [num]

Which of the grammars correctly generate the declaration mentioned above?

Both G1 and G2

Only G1

Only G2

Neither G1 nor G2

Correct Answer : A

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 57

Consider the following processes, with the arrival time and the length of the CPU burst given in milliseconds. The scheduling algorithm used is preemptive shortest remaining-time first.

\(\begin{array}{|c|c|c|} \hline \text{Process} & \text{Arrival Time} & \text{Burst Time} \\ P_{1} & 0 & 10 \\ P_{2} & 3 & 6 \\ P_{3} & 7 & 1 \\ P_{4} & 8 & 3 \\ \hline \end{array}\)

The average turn around time of these processes is __________ milliseconds.

Correct Answer : 8.2 to 8.3

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 58

Consider the following two-process synchronization solution.

Process 0
---------
Entry: loop while (turn == 1);
(critical section)
Exit: turn = 1;

Process 1
----------
Entry: loop while (turn == 0);
(critical section)
Exit: turn = 0;

The shared variable turn is initialized to zero. Which one of the following is TRUE?

This is a correct two-process synchronization solution.

This solution violates mutual exclusion requirement.

This solution violates progress requirement.

This solution violates bounded wait requirement.

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 59

Consider a non-negative counting semaphore \(S\). The operation \(P(S)\) decrements \(S\), and \(V(S)\) increments \(S\). During an execution, 20 \(P(S)\) operations and 12 \(V(S)\) operations are issued in some order. The largest initial value of \(S\) for which at least one \(P(S)\) operation will remain blocked is __________ .

Correct Answer : 7

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 60

A file system uses an in-memory cache to cache disk blocks. The miss rate of the cache is shown in the figure. The latency to read a block from the cache is 1 ms and to read a block from the disk is 10 ms. Assume that the cost of checking whether a block exists in the cache is negligible. Available cache sizes are in multiples of 10 MB.

The smallest cache size required to ensure an average read latency of less than 6 ms is __________ MB.

Correct Answer : 30

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 61

Consider the following database schedule with two transactions, \(T_1\) and \(T_2\).

\(S= r_{2}\left(X\right); r_{1}\left(X\right); r_{2} \left(Y\right); w_{1} \left(X\right); r_{1} \left(Y\right); w_{2} \left(X\right); a_{1}; a_{2}\)

where \(r_i(Z)\) denotes a read operation by transaction \(T_i\) on a variable \(Z\), \(w_i(Z)\) denotes a write operation by \(T_i\) on a variable \(Z\) and ai denotes an abort by transaction \(T_i\) .

Which one of the following statements about the above schedule is TRUE?

\(S\) is non-recoverable

\(S\) is recoverable, but has a cascading abort

\(S\) does not have a cascading abort

\(S\) is strict

Correct Answer : C

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 62

Consider the following database table named water_schemes :

\(\overset{\text{Water_schemes}}{\begin{array}{|c|c|c|}\hline \textbf{scheme_no}& \textbf{district_name}& \textbf{capacity} \\\hline 1& \text{Ajmer}& 20 \\ 1& \text{Bikaner}& 10 \\ 2& \text{Bikaner}& 10 \\ 3& \text{Bikaner}&20 \\ 1& \text{Churu}& 10 \\ 2& \text{Churu}& 20 \\ 1& \text{Dungargarh}& 10 \\\hline \end{array}}\)

The number of tuples returned by the following SQL query is _____________ .


with total (name, capacity) as 

    select district_name, sum (capacity) 

    from water_schemes

    group by district_name 

with total_avg (capacity) as 

   select avg (capacity) 

   from total 

select name 

   from total, total_avg 

   where total.capacity ≥ total_avg.capacity

Correct Answer : 2

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 63

A network has a data transmission bandwidth of 20×10⁶ bits per second. It uses CSMA/CD in the MAC layer. The maximum signal propagation time from one node to another node is 40 microseconds. The minimum size of a frame in the network is bytes.

Correct Answer : 200

Question Type : NAT

Max Marks : 2

Negative Marks : 0

Question : 64

For the IEEE 802.11 MAC protocol for wireless communication, which of the following statements is/are TRUE?

I. At least three non-overlapping channels are available for transmissions.

II. The RTS-CTS mechanism is used for collision detection.

III. Unicast frames are ACKed.

All I, II, and III

I and III only

II and III only

II only

Correct Answer : B

Question Type : MCQ

Max Marks : 2

Negative Marks : 0.67

Question : 65

Consider a 128×10³ bits/second satellite communication link with one way propagation delay of 150 milliseconds. Selective retransmission (repeat) protocol is used on this link to send data with a frame size of 1 kilobyte. Neglect the transmission time of acknowledgement. The minimum number of bits required for the sequence number field to achieve 100% utilization is _____________ .

Correct Answer : 4

Question Type : NAT

Max Marks : 2

Negative Marks : 0

GATE 2016 CS SET - 2