As a rule, he or she who has the most information will have the greatest success in life.
1. Consider the following C function.
float f,(float x, int y) {
float p, s;
int i;
for (s=1, p=1, i=1; i<y; i++) {
p*= x/i;
s+=p;
}
return s;
}
For large values of y, the return value of the function f best approximates
(A) XY
(B) eX
(C) ln(1+x)
(D) XX
View/Hide Ans
Correct Answer is B
2. Assume the following C variable declaration
int *A[10], B[10][10];
of the following expressions:
I. A[2]
II. A[2][3]
III. B[1]
IV. B[2][3]
Which will not give compile-time errors if used as left hand sides of assignment
statements in a C program?
(A) I,II, and IV only
(B) II, III, and IV only
(C) II and IV only
(D) IV only
View/Hide Ans
Correct Answer is A
3. Let P(E) denote the probability of the event E.
Given P(A) = 1, P(B) = 1/2, the values of P(A|B) and P(B|A) respectively are
(A) 1/4, 1/2
(B) 1/2, 1/4
(C) 1/2, 1
(D) 1, 1/2
View/Hide Ans
Correct Answer is D
4. Let A be a sequence of 8 distinct integers sorted in ascending order. How many
distinct pairs of sequences, B and C are there such that
(i) each is sorted in ascending order
(ii) B has 5 and C has 3 elements, and
(iii) the result of merging B and C gives A?
(A) 2
(B) 30
(C) 56
(D) 256
View/Hide Ans
Correct Answer is C
5. n couples are invited to a party with the condition that every husband should be
accompanied by his wife. However, a wife need not be accompanied by her
husband.
The number of different gatherings possible at the party is
View/Hide Ans
Correct Answer is B
6. Let T(n) be the number of different binary search trees on n distinct elements.
Then
where x is
(A) n-k+1
(B) n-k
(C) n-k-1
(D) n-k-2
View/Hide Ans
Correct Answer is B
7. Consider the set ∑* of all strings over the alphabet
∑={0, 1}. ∑* with the
concatenation operator for strings
(A) does not form a group
(B) forms a non-commutative group
(C) does not have a right identity element
(D) forms a group if the empty string is removed from ∑*
View/Hide Ans
Correct Answer is A
8. Let G be an arbitrary graph with n nodes and k components. If a vertex is
removed from G, the number of components in the resultant graph must
necessarily lie between
(A) k and n
(B) k-1 and k+1
(C) k-1 and n-1
(D) k+1 and n-k
View/Hide Ans
Correct Answer is C
9. Assuming all numbers are in 2’s complement representation, which of the
following numbers is divisible by 11111011?
(A) 11100111
(B) 11100100
(C) 11010111
(D) 11011011
View/Hide Ans
Correct Answer is A
10. For a pipelined CPU with a single ALU, consider the following situations
I. The j+1st instruction uses the result of the jth instruction as an operand
II. The execution of a conditional jump instruction
III. The jth and j+1st instructions require the ALU at the same time
Which of the above can cause a hazard?
(A) I and II only
(B) II and III only
(C) III only
(D) All the three
View/Hide Ans
Correct Answer is D
11. Consider an array multiplier for multiplying two n bit numbers.
If each gate in the
circuit has a unit delay, the total delay of the multiplier is
(A) θ(1)
(B) θ(log n)
(C) θ(n)
(D) θ(n2)
View/Hide Ans
Correct Answer is C
12. Ram and Shyam have been asked to show that a certain problem Π is NP complete.
Ram shows a polynomial time reduction from the 3-SAT problem to Π,
and Shyam shows a polynomial time reduction from Π to 3-SAT.
Which of the
following can be inferred from these reductions?
(A) Π is NP-hard but not NP-complete
(B) Π is in NP, but is not NP-complete
(C) Π is NP-complete
(D) Π is neither NP-hard, nor in NP
View/Hide Ans
Correct Answer is C
13. Nobody knows yet if P = NP. Consider the language L defined as follows.
Which of the following statements is true?
(A) L is recursive
(B) L is recursively enumerable but not recursive
(C) L is not recursively enumerable
(D) Whether L is recursive or not will be known after we find out if P=NP
View/Hide Ans
Correct Answer is A
14. The regular expression 0*(10*)* denotes the same set as
(A) (1*0)*1*
(B) 0+(0+10)*
(C) (0+1)*10(0+1)*
(D) None of the above
View/Hide Ans
Correct Answer is A
15. If the strings of a language L can be effectively enumerated in lexicographic (i.e.,
alphabetic) order, which of the following statements is true?
(A) L is necessarily finite
(B) L is regular but not necessarily finite
(C) L is context free but not necessarily regular
(D) L is recursive but not necessarily context free
View/Hide Ans
Correct Answer is D
16. Which of the following suffices to convert an arbitrary CFG to an LL(1) grammar?
(A) Removing left recursion alone
(B) Factoring the grammar alone
(C) Removing left recursion and factoring the grammar
(D) None of the above
View/Hide Ans
Correct Answer is D
17. Assume that the SLR parser for a grammar G has n1 states and the LALR parser
for G has n2 states.
The relationship between n1 and n2 is
(A) n1 is necessarily less than n2
(B) n1 is necessarily equal to n2
(C) n1 is necessarily greater than n2
(D) None of the above
View/Hide Ans
Correct Answer is B
18. In a bottom-up evaluation of a syntax directed definition, inherited attributes can
(A) always be evaluated
(B) be evaluated only if the definition is L-attributed
(C) be evaluated only if the definition has synthesized attributes
(D) never be evaluated
View/Hide Ans
Correct Answer is B
19. Suppose the numbers 7, 5, 1, 8, 3, 6, 0, 9, 4, 2 are inserted in that order into an
initially empty binary search tree. The binary search tree uses the usual ordering
on natural numbers.
What is the in-order traversal sequence of the resultant
tree?
(A) 7 5 1 0 3 2 4 6 8 9
(B) 0 2 4 3 1 6 5 9 8 7
(C) 0 1 2 3 4 5 6 7 8 9
(D) 9 8 6 4 2 3 0 1 5 7
View/Hide Ans
Correct Answer is C
20. Consider the following three claims
I. (n+k)m = Θ(nm) where k and m are constants
II. 2n+1 = O(2n)
III. 22n+1 = O(2n)
Which of these claims are correct?
(A) I and II
(B) I and III
(C) II and III
(D) I, II, and III
View/Hide Ans
Correct Answer is A
21. Consider the following graph
22. The usual Θ(n2) implementation of Insertion Sort to sort an array uses linear
search to identify the position where an element is to be inserted into the already
sorted part of the array.
If, instead, we use binary search to identify the position,
the worst case running time will
(A) remain Θ(n2)
(B) become Θ(n (log n)2)
(C) become Θ(n log n)
(D) become Θ(n)
View/Hide Ans
Correct Answer is A
23. In a heap with n elements with the smallest element at the root, the 7th smallest
element can be found in time
(A) Θ(n log n)
(B) Θ(n)
(C) Θ(log n)
(D) Θ(1)
View/Hide Ans
Correct Answer is D
24. Which of the following statements is FALSE?
(A) In statically typed languages, each variable in a program has a fixed type
(B) In un-typed languages, values do not have any types
(C) In dynamically typed languages, variables have no types
(D) In all statically typed languages, each variable in a program is associated
with values of only a single type during the execution of the program
View/Hide Ans
Correct Answer is A
25. Using a larger block size in a fixed block size file system leads to
(A) better disk throughput but poorer disk space utilization
(B) better disk throughput and better disk space utilization
(C) poorer disk throughput but better disk space utilization
(D) poorer disk throughput and poorer disk space utilization
View/Hide Ans
Correct Answer is A
26. In a system with 32 bit virtual addresses and 1 KB page size, use of one-level
page tables for virtual to physical address translation is not practical because of
(A) the large amount of internal fragmentation
(B) the large amount of external fragmentation
(C) the large memory overhead in maintaining page tables
(D) the large computation overhead in the translation process
View/Hide Ans
Correct Answer is C
27. Which of the following assertions is FALSE about the Internet Protocol(IP)?
(A) It is possible for a computer to have multiple IP addresses
(B) IP packets from the same source to the same destination can take different
routes in the network
(C) IP ensures that a packet is discarded if it is unable to reach its destination
within a given number of hops
(D) The packet source cannot set the route of an outgoing packets; the route is
determined only by the routing tables in the routers on the way
View/Hide Ans
Correct Answer is D
28. Which of the following functionalities must be implemented by a transport
protocol over and above the network protocol?
(A) Recovery from packet losses
(B) Detection of duplicate packets
(C) Packet delivery in the correct order
(D) End to end connectivity
View/Hide Ans
Correct Answer is D
29. Which of the following scenarios may lead to an irrecoverable error in a database
system?
(A) A transaction writes a data item after it is read by an uncommitted
transaction
(B) A transaction reads a data item after it is read by an uncommitted
transaction
(C) A transaction reads a data item after it is written by a committed transaction
(D) A transaction reads a data item after it is written by an uncommitted
transaction
View/Hide Ans
Correct Answer is D
30. Consider the following SQL query
select distinct a1, a2, ..., an
from r1, r2, ..., rm
where P
For an arbitrary predicate P, this query is equivalent to which of the following
relational algebra expressions?
View/Hide Ans
Correct Answer is A
31. Let (S, ≤) be a partial order with two minimal elements a and b, and a maximum
element c. Let P: S → {True, False} be a predicate defined on S.
Suppose that
P(a) = True, P(b) = False and P(x) ⇒ P(y) for all x, y ∈ S satisfying x≤, where ⇒ stands for logical implication.
Which of the following statements
CANNOT be true?
(A) P(x) = True for all x ∈ S such that x ≠ b
(B) P(x) = False for all x ∈ S such that x ≠ a and x ≠ c
(C) P(x) = False for all x ∈ S such that b ≤ x and x ≠ c
(D) P(x) = False for all x ∈ S such that a ≤ x and b ≤ x
View/Hide Ans
Correct Answer is D
32. Which of the following is a valid first order formula?
(Note: Here ∝ and β are first order
formulae with x as their only free variable)
View/Hide Ans
Correct Answer is D
33. Consider the following formula and its two interpretations I1 and I2
Which of the following statements is true?
(A) I1 satisfies a, I2 does not
(B) I2 satisfies a, I1 does not
(C) Neither I2 nor I1 satisfies ∝
(D) Both I1 and I2 satisfy ∝
View/Hide Ans
Correct Answer is C
34. m identical balls are to be placed in n distinct bags. You are given that m ≥ kn,
where k is a natural number ≥1.
In how many ways, can the balls be placed in the
bags if each bag must contain at least k balls?
View/Hide Ans
Correct Answer is B
35. Consider the following recurrence relation
T(1) = 1
T(n + 1) = T(n) + ⌊(√n+1)⌋ for all n ≥ 1
The value of T(m2) for m ≥ 1 is
View/Hide Ans
Correct Answer is B
36. How many perfect matching are there in a complete graph of 6 vertices?
(A) 15
(B) 24
(C) 30
(D) 60
View/Hide Ans
Correct Answer is A
37. Let f : A → B be an injective(one-to-one) function.
Define g : 2A → 2B as: g(C) = {f(x) | x ∈ C}, for all subsets C of A.
Define h : 2B → 2A as: h(D) = {x | x ∈ A, f(x) ∈ D}, for all subsets D of B.
Which of the following statements is always true?
(A) g(h(D)) ⊆ D
(B) g(h(D)) ⊇ D
(C) g(h(D)) ∩ D = ∅
(D) g(h(D)) ∩ (B-D) ≠ ∅
View/Hide Ans
Correct Answer is A
38. Consider the set {a, b, c} with binary operators + and × defined as follows.
39. Let ∑ = {a, b, c, d, e} be an alphabet. We define an encoding scheme as follows:
g(a) = 3, g(b) = 5, g(c) = 7, g(d) = 9, g(e) = 11.
Which of the following numbers is the encoding, h, of a non-empty sequence of
strings?
(A) 273757
(B) 283858
(C) 293959
(D) 210510710
View/Hide Ans
Correct Answer is B
40. A graph G = (V, E) satisfies |E| ≤ 3|V|-6. The min-degree of G is defined as min{degree(v)}.
Therefore, min-degree of G cannot be
(A) 3
(B) 4
(C) 5
(D) 6
View/Hide Ans
Correct Answer is D
41. Consider the following system of linear equations
42. A piecewise linear function f(x) is plotted using thick solid lines in the figure
below (the plot is drawn to scale).
43. The following is a scheme for floating point number representation using 16 bits.
44. A 1-input, 2-output synchronous sequential circuit behaves as follows:
Let zk, nk denote the number of 0’s and 1’s respectively in initial k bits of the
input (zk+nk=k).
The circuit outputs 00 until one of the following conditions holds:
i) zk-nk=2. In this case, the output at the k-th and all subsequent clock ticks
is 10.
ii) nk-zk = 2. In this case, the output at the k-th and all subsequent clock ticks
is 01.
What is the minimum number of states required in the state transition graph of
the above circuit?
(A) 5
(B) 6
(C) 7
(D) 8
View/Hide Ans
Correct Answer is B
45. The literal count of a Boolean expression is the sum of the number of times each
literal appears in the expression. For example, the literal count of (xy + xz’) is 4.
What are the minimum possible literal counts of the product-of-sum and sum-ofproduct
representations respectively of the function given by the following
Karnaugh map? Here, X denotes "don’t care".
46. Consider the ALU shown below.
47. Consider the following circuit composed of XOR gates and non-inverting buffers.
48. Consider the following assembly language program for a hypothetical processor
A, B, and C are 8 bit registers. The meanings of various instructions are shown as
comments.
49. Consider the following assembly language program for a hypothetical processor
A, B, and C are 8 bit registers. The meanings of various instructions are shown as
comments.
50. Consider the following deterministic finite state automaton M.
51. Let G = ({S},{a,b},R,S) be a CFG where the rule set R is S → a S b | S S | ε
Which of the following statements is true?
(A) G is not ambiguous
(B) There exist x, y ∈ L(G) such that xy ∉ L(G)
(C) There is a deterministic pushdown automaton that accepts L(G)
(D) We can find a deterministic finite state automaton that accepts L(G)
View/Hide Ans
Correct Answer is C
52. Consider two languages L1 and L2, each on the alphabet ∑.
Let f: ∑* → ∑* be a
polynomial time computable bijection such that (∀x)[x ∈ L1 iff f(x) ∈ L2].
Further, let f-1 be also polynomial time computable.
Which of the following CANNOT be true?
(A) L1 ∈ P and L2 is finite
(B) L1 ∈ NP and L2 ∈ P
(C) L1 is undecidable and L2 is decidable
(D) L1 is recursively enumerable and L2 is recursive
View/Hide Ans
Correct Answer is C
53. A single tape Turing Machine M has two states q0 and q1, of which q0 is the
starting state. The tape alphabet of M is {0, 1, B} and its input alphabet is {0,
1}. The symbol B is the blank symbol used to indicate end of an input string. The
transition function of M is described in the following table.
54. Define languages L0 and L1 as follows:
L0 = {<M, w, 0> | M halts on w}
L1 = {<M, w, 1> | M does not halt on w}
Here <M, w, i> is a triplet, whose first component, M, is an encoding of a Turing
Machine, second component, w, is a string, and third component, i, is a bit.
Let L = L0∪L1. Which of the following is true?
(A) L is recursively enumerable, but L' is not
(B) L' is recursively enumerable, but L is not
(C) Both L and L' are recursive
(D) Neither L nor L' is recursively enumerable
View/Hide Ans
Correct Answer is A
55. Consider the NFA M shown below.
56. Consider the grammar shown below
S → i E t S S' | a
S' → e S |ε
E → b
In the predictive parse table, M, of this grammar, the entries M[S', e] and M[S', $] respectively are
(A) {S' → e S} and {S' →ε}
(B) {S' → e S} and { }
(C) {S' → ε} and {S' → ε}
(D) {S' → e S, S' → ε} and {S' → ε}
View/Hide Ans
Correct Answer is D
57. Consider the grammar shown below.
S → C C
C → c C | d
This grammar is
(A) LL(1)
(B) SLR(1) but not LL(1)
(C) LALR(1) but not SLR(1)
(D) LR(l) but not LALR(1)
View/Hide Ans
Correct Answer is A
58. Consider the translation scheme shown below.
S → T R
R → + T {print(’+’);} R|ε
T → num {print(num.val);}
Here num is a token that represents an integer and num.val represents the
corresponding integer value.
For an input string ‘9 + 5 + 2’, this translation
scheme will print
(A) 9 + 5 + 2
(B) 9 5 + 2 +
(C) 9 5 2 + +
(D) + + 9 5 2
View/Hide Ans
Correct Answer is B
59. Consider the syntax directed definition shown below.
i) S → id : = E {gen(id.place = E.place;);}
ii) E → E1 + E2 {t = newtemp( ); gen(t = E1.place + E2.place;); E.place = ti;}
iii) E → id {E.place = id.place;}
Here, gen is a function that generates the output code, and newtemp is a
function that returns the name of a new temporary variable on every call.
Assume that ti’s are the temporary variable names generated by newtemp.
For the statement 'X : = Y + Z', the 3-address code sequence generated by this
definition is
(A) X = Y + Z
(B) t1 = Y + Z; X = t1
(C) t1 = Y; t2 = t1 + Z; X = t2
(D) t1 = Y; t2 = Z; t3 = t1 +
t2; X = t3
View/Hide Ans
Correct Answer is B
60. A program consists of two modules executed sequentially. Let f1(t) and f2(t)
respectively denote the probability density functions of time taken to execute the
two modules.
The probability density function of the overall time taken to execute
the program is given by
View/Hide Ans
Correct Answer is C
61. In a permutation a1 ... an, of n distinct integers, an inversion is a pair (ai, aj) such that
i < j and ai > aj
If all permutations are equally likely, what is the expected number of inversions
in a randomly chosen permutation of 1. . . n?
(A) n(n-1)/2
(B) n(n-1)/4
(C) n(n+1)/4
(D) 2n[log2n]
View/Hide Ans
Correct Answer is B
62. In a permutation a1 ... an, of n distinct integers, an inversion is a pair (ai, aj) such that
i < j and ai > aj
What would be the worst case time complexity of the Insertion Sort algorithm, if
the inputs are restricted to permutations of 1. . . n with at most n inversions?
(A) Θ(n2)
(B) Θ(n log n)
(C) Θ(n1.5)
(D) Θ(n)
View/Hide Ans
Correct Answer is D
63. A data structure is required for storing a set of integers such that each of the
following operations can be done in O(log n) time, where n is the number of
elements in the set.
I. Deletion of the smallest element.
II. Insertion of an element if it is not already present in the set.
Which of the following data structures can be used for this purpose?
(A) A heap can be used but not a balanced binary search tree
(B) A balanced binary search tree can be used but not a heap
(C) Both balanced binary search tree and heap can be used
(D) Neither balanced binary search tree nor heap can be used
View/Hide Ans
Correct Answer is B
64. Let S be a stack of size n≥1. Starting with the empty stack, suppose we push the
first n natural numbers in sequence, and then perform n pop operations.
Assume that Push and Pop operations take X seconds each, and Y seconds elapse
between the end of one such stack operation and the start of the next operation.
For m≥1, define the stack-life of m as the time elapsed from the end of Push(m)
to the start of the pop operation that removes m from S.
The average stack-life
of an element of this stack is
(A) n(X + Y)
(B) 3Y + 2X
(C) n(X + Y) - X
(D) Y + 2X
View/Hide Ans
Correct Answer is C
65. Consider the following 2-3-4 tree (i.e., B-tree with a minimum degree of two) in
which each data item is a letter. The usual alphabetical ordering of letters is used
in constructing the tree.
What is the result of inserting G in the above tree?
(A)
(B)
(C)
(D) None of the above
View/Hide Ans
Correct Answer is B
66. The cube root of a natural number n is defined as the largest natural number m
such that m3≤n.
The complexity of computing the cube root of n (n is represented
in binary notation) is
(A) O(n) but not O(n0.5)
(B) O(n0.5) but not O((log nk)) for any constant k > 0
(C) O((log n)k) for some constant k > 0, but not O((log log n)m) for any constant m > 0
(D) O((log log n)k) for some constant k > 0.5,
but not O((log log n)0.5)
View/Hide Ans
Correct Answer is C
67. Let G = (V, E) be an undirected graph with a subgraph G1 = (V1, E1). Weights are
assigned to edges of G as follows.
A single-source shortest path algorithm is executed on the weighted graph
(V, E, w) with an arbitrary vertex v1 of V1 as the source.
Which of the following can
always be inferred from the path costs computed?
(A) The number of edges in the shortest paths from v1 to all vertices of G
(B) G1 is connected
(C) V1 forms a clique in G
(D) G1 is a tree
View/Hide Ans
Correct Answer is B
68. What is the weight of a minimum spanning tree of the following graph?
69. The following are the starting and ending times of activities A, B, C, D, E, F, G
and H respectively in chronological order: "as bs cs ae ds es fs be de gs ee fe hs ge
he".
Here, xs denotes the starting time and xe denotes the ending time
of activity X. We need to schedule the activities in a set of rooms available to us. An activity can be scheduled in a room only if the room is reserved for the activity for its
entire duration.
What is the minimum number of rooms required?
(A) 3
(B) 4
(C) 5
(D) 6
View/Hide Ans
Correct Answer is B
70. Let G = (V, E) be a directed graph with n vertices. A path from vi to vj in G is a
sequence of vertices (vi, vi+1, ....., vj) such that (vk, vk+1) ∈ E for all k in i through
j - 1. A simple path is a path in which no vertex appears more than once.
Consider the following algorithm.
for i = 1 to n
for j = 1 to n
for k = 1 to n
A[j,k] = max(A[j,k], A[j,i] + A[i,k]);
Which of the following statements is necessarily true for all j and k after
termination of the above algorithm?
(A) A[j, k] ≤ n
(B) If A[j, j] ≥ n-1, then G has a Hamiltonian cycle
(C) If there exists a path from j to k, A[j, k] contains the longest path length from j to k
(D) If there exists a path from j to k, every simple path from j to k
contains at most A[j, k] edges
View/Hide Ans
Correct Answer is D
71. Consider the following logic program P
A(x) ← B(x, y), C(y)
← B(x,x)
Which of the following first order sentences is equivalent to P?
(A) (∀x) [(∃y) [B(x,y) ∧ C(y)] ⇒ A(x)] ∧ ¬(∃x)[B(x,x)]
(B) (∀x) [(∀y) [B(x,y) ∧ C(y)] ⇒ A(x)] ∧ ¬(∃x)[B(x,x)]
(C) (∀x) [(∃y) [B(x,y) ∧ C(y)] ⇒ A(x)] ∨ ¬(∃x)[B(x,x)]
(D) (∀x) [(∀y) [B(x,y) ∧ C(y)] ⇒ A(x)] ∧ (∃x)[B(x,x)]
View/Hide Ans
Correct Answer is C
72. The following resolution rule is used in logic programming.
Derive clause (P ∨ Q) from clauses (P ∨ R), (Q ∨ ¬R).
Which of the following statements related to this rule is FALSE?
(A) ((P ∨ R) ∧ (Q ∨ ¬R)) ⇒ (P ∨ Q) is logically valid
(B) (P ∨ Q) ⇒ ((P ∨ R) ∧ (Q ∨ ¬R)) is logically valid
(C) (P ∨ Q) is satisfiable if and only if (P ∨ R) ∧ (Q ∨ ¬R) is satisfiable
(D) (P ∨ Q) ⇒ FALSE if and only if both P and Q are unsatisfiable
View/Hide Ans
Correct Answer is B
73. The following program fragment is written in a programming language that allows global
variables and does not allow nested declarations of functions.
global int i = 100, j = 5;
void P(x) {
int i = 10;
print(x + 10);
i = 200;
j = 20;
print (x);
}
main() {P(i + j);}
If the programming language uses static scoping and call by need parameter
passing mechanism, the values printed by the above program are
(A) 115, 220
(B) 25, 220
(C) 25, 15
(D) 115, 105
View/Hide Ans
Correct Answer is D
74. The following program fragment is written in a programming language that allows global
variables and does not allow nested declarations of functions.
global int i = 100, j = 5;
void P(x) {
int i = 10;
print(x + 10);
i = 200;
j = 20;
print (x);
}
main() {P(i + j);}
If the programming language uses dynamic scoping and call by name parameter
passing mechanism, the values printed by the above program are
(A) 115, 220
(B) 25, 220
(C) 25, 15
(D) 115, 105
View/Hide Ans
Correct Answer is A
75. Consider the following class definitions in a hypothetical Object Oriented
language that supports inheritance and uses dynamic binding. The language
should not be assumed to be either Java or C++, though the syntax is similar.
Now consider the following program fragment:
Class P {
Class Q subclass of P {
void f(int i) {
void f(int i) {
print(i);
print(2*i);
}
}
}
}
Px = new Q()
Qy = new Q();
Pz = new Q();
x.f(1); ((P)y).f(1); z.f(1);
Here ((P)y) denotes a typecast of y to P.
The output produced by executing the
above program fragment will be
(A) 1 2 1
(B) 2 1 1
(C) 2 1 2
(D) 2 2 2
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Correct Answer is D
76. Which of the following is NOT an advantage of using shared, dynamically linked
libraries as opposed to using statically linked libraries?
(A) Smaller sizes of executable files
(B) Lesser overall page fault rate in the system
(C) Faster program startup
(D) Existing programs need not be re-linked to take advantage of newer versions
of libraries
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Correct Answer is C
77. A uni-processor computer system only has two processes, both of which alternate
10 ms CPU bursts with 90 ms I/O bursts. Both the processes were created at
nearly the same time. The I/O of both processes can proceed in parallel.
Which of
the following scheduling strategies will result in the least CPU utilization (over a
long period of time) for this system?
(A) First come first served scheduling
(B) Shortest remaining time first scheduling
(C) Static priority scheduling with different priorities for the two processes
(D) Round robin scheduling with a time quantum of 5 ms
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Correct Answer is D
78. A processor uses 2-level page tables for virtual to physical address translation. Page
tables for both levels are stored in the main memory. Virtual and physical addresses are
both 32 bits wide. The memory is byte addressable. For virtual to physical address
translation, the 10 most significant bits of the virtual address are used as index into the
first level page table while the next 10 bits are used as index into the second level page
table. The 12 least significant bits of the virtual address are used as offset within the
page. Assume that the page table entries in both levels of page tables are 4 bytes wide.
Further, the processor has a translation look-aside buffer (TLB), with a hit rate of 96%.
The TLB caches recently used virtual page numbers and the corresponding physical page
numbers. The processor also has a physically addressed cache with a hit rate of 90%.
Main memory access time is 10 ns, cache access time is 1 ns, and TLB access time is
also 1 ns.
Assuming that no page faults occur, the average time taken to access a virtual
address is approximately (to the nearest 0.5 ns)
(A) 1.5 ns
(B) 2 ns
(C) 3 ns
(D) 4 ns
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Correct Answer is D
79. A processor uses 2-level page tables for virtual to physical address translation. Page
tables for both levels are stored in the main memory. Virtual and physical addresses are
both 32 bits wide. The memory is byte addressable. For virtual to physical address
translation, the 10 most significant bits of the virtual address are used as index into the
first level page table while the next 10 bits are used as index into the second level page
table. The 12 least significant bits of the virtual address are used as offset within the
page. Assume that the page table entries in both levels of page tables are 4 bytes wide.
Further, the processor has a translation look-aside buffer (TLB), with a hit rate of 96%.
The TLB caches recently used virtual page numbers and the corresponding physical page
numbers. The processor also has a physically addressed cache with a hit rate of 90%.
Main memory access time is 10 ns, cache access time is 1 ns, and TLB access time is
also 1 ns.
Suppose a process has only the following pages in its virtual address space: two
contiguous code pages starting at virtual address 0×00000000, two contiguous
data pages starting at virtual address 0×00400000, and a stack page starting at
virtual address 0×FFFFF000. The amount of memory required for storing the page
tables of this process is
(A) 8 KB
(B) 12 KB
(C) 16 KB
(D) 20 KB
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Correct Answer is C
80. Suppose we want to synchronize two concurrent processes P and Q using binary
semaphores S and T.
The code for the processes P and Q is shown below
Synchronization statements can be inserted only at points W, X, Y, and Z
Process P:
Process Q:
while (1) {
while (1) {
W:
Y:
print ‘0’;
print ‘1’;
print ‘0’;
print ‘1’;
X:
Z:
}
}
Which of the following will always lead to an output staring with ‘001100110011’?
(A) P(S) at W, V(S) at X, P(T) at Y, V(T) at Z, S and T initially 1
(B) P(S) at W, V(T) at X, P(T) at Y, V(S) at Z, S initially 1, and T initially 0
(C) P(S) at W, V(T) at X, P(T) at Y, V(S) at Z, S and T initially 1
(D) P(S) at W, V(S) at X, P(T) at Y, V(T) at Z, S initially 1, and T initially 0
View/Hide Ans
Correct Answer is B
81. Suppose we want to synchronize two concurrent processes P and Q using binary
semaphores S and T.
The code for the processes P and Q is shown below
Synchronization statements can be inserted only at points W, X, Y, and Z
Process P:
Process Q:
while (1) {
while (1) {
W:
Y:
print ‘0’;
print ‘1’;
print ‘0’;
print ‘1’;
X:
Z:
}
}
Which of the following will ensure that the output string never contains a
substring of the form 01n0 or 10n1 where n is odd?
(A) P(S) at W, V(S) at X, P(T) at Y, V(T) at Z, S and T initially 1
(B) P(S) at W, V(T) at X, P(T) at Y, V(S) at Z, S and T initially 1
(C) P(S) at W, V(S) at X, P(S) at Y, V(S) at Z, S initially 1
(D) V(S) at W, V(T) at X, P(S) at Y, P(T) at Z, S and T initially 1
View/Hide Ans
Correct Answer is C
82. The subnet mask for a particular network is 255.255.31.0.
Which of the following
pairs of IP addresses could belong to this network?
(A) 172.57.88.62 and 172.56.87.233
(B) 10.35.28.2 and 10.35.29.4
(C) 191.203.31.87 and 191.234.31.88
(D) 128.8.129.43 and 128.8.161.55
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Correct Answer is D
83. A 2 km long broadcast LAN has 107 bps bandwidth and uses CSMA/CD. The signal
travels along the wire at 2×108 m/s.
What is the minimum packet size that can be
used on this network?
(A) 50 bytes
(B) 100 bytes
(C) 200 bytes
(D) None of the above
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Correct Answer is D
84. Host A is sending data to host B over a full duplex link. A and B are using the
sliding window protocol for flow control. The send and receive window sizes are 5
packets each. Data packets (sent only from A to B) are all 1000 bytes long and
the transmission time for such a packet is 50 μs Acknowledgement packets (sent
only from B to A) are very small and require negligible transmission time. The propagation delay over the link is 200 μs.
What is the maximum achievable
throughput in this communication?
(A) 7.69×106 bps
(B) 11.11×106 bps
(C) 12.33×106 bps
(D) 15.00×106 bps
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Correct Answer is B
85. Consider the following functional dependencies in a database.
Date_of_Birth → Age
Age → Eligibility
Name → Roll_number
Roll_number → Name
Course_number → Course_name
Course_number → Instructor
(Roll_number, Course_number) → Grade
The relation (Roll_number, Name, Date_of_birth, Age) is
(A) in second normal form but not in third normal form
(B) in third normal form but not in BCNF
(C) in BCNF
(D) in none of the above
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Correct Answer is D
86. Consider the set of relations shown below and the SQL query that follows.
Students: (Roll_number, Name, Date_of_birth)
Courses: (Course number, Course_name, Instructor)
Grades: (Roll_number, Course_number, Grade)
select distinct Name
from Students, Courses, Grades
where Students. Roll_number = Grades.Roll_number
and Courses.Instructor = Korth
and Courses.Course_number = Grades.Course_number
and Grades.grade=A
Which of the following sets is computed by the above query?
(A) Names of students who have got an A grade in all courses taught by Korth
(B) Names of students who have got an A grade in all courses
(C) Names of students who have got an A grade in at least one of the courses
taught by Korth
(D) None of the above
View/Hide Ans
Correct Answer is C
87. Consider three data items D1, D2, and D3, and the following execution schedule
of transactions T1, T2, and T3. In the diagram, R(D) and W(D) denote the actions
reading and writing the data item D respectively.
88. In the following C program fragment, j, k, n and TwoLog_n are integer variables,
and A is an array of integers. The variable n is initialized to an integer ≥3, and
TwoLog_n is initialized to the value of 2*⌊log2 n⌋
for (k=3; k <= n; k++)
A[k] = 0;
for (k=2; k <= TwoLog_n; k++)
for (j=k+1; j <= n; j++)
A[j] = A[j] || (j%k);
for (j=3; j <= n; j++)
if (!A[j]) printf("%d ",j);
The set of numbers printed by this program fragment is
(A) {m| m ≤ n, (∃i)[m=i!]}
(B) {m| m ≤ n, (∃i)[m=i2]}
(C) {m| m ≤ n, m is prime}
(D) { }
View/Hide Ans
Correct Answer is B
89. Consider the C program shown below.
#include <stdio.h>
#define print(x) printf(”%d “, x)
int x;
void Q(int z) {
z += x; print(z);
}
void P(int *y) {
int x = *y+2;
Q(x); *y = x-1;
print(x);
}
main(void) {
x = 5;
P(&x)
print(x);
}
The output of this program is
(A) 12 76
(B) 22 12 11
(C) 14 66
(D) 7 6 6
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Correct Answer is A
90. Consider the function f defined below.
struct item {
int data;
struct item * next;
};
int f(struct item *p) {
return ((p==NULL)||(p->next==NULL)||
((p->data<=p->next->data)&&f(p->next)));
}
For a given linked list p, the function f returns 1 if and only if
(A) the list is empty or has exactly one element
(B) the elements in the list are sorted in non-decreasing order of data value
(C) the elements in the list are sorted in non-increasing order of data value
(D) not all elements in the list have the same data value
View/Hide Ans
Correct Answer is B
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