Don't judge each day by the harvest you reap but by the seeds that you plant.
1. Consider the following two statements about the function f (x) = |x| :
P. f (x) is continuous for all real values of x
Q. f (x) is differentiable for all real values of x
Which of the following is TRUE?
(A) P is true and Q is false.
(B) P is false and Q is true.
(C) Both P and Q are true.
(D) Both P and Q are false.
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Correct Answer is A
2. Let S be a set of n elements. The number of ordered pairs in the largest and the
smallest equivalence relations on S are:
(A) n and n
(B) n2 and n
(C) n2 and 0
(D) n and 1
View/Hide Ans
Correct Answer is B
3. What is the maximum number of different Boolean functions involving n Boolean
variables?
(A) n2
(B) 2n
(C) 22n
(D) 2n2
View/Hide Ans
Correct Answer is C
4. Let G be the non-planar graph with the minimum possible number of edges. Then
G has
(A) 9 edges and 5 vertices
(B) 9 edges and 6 vertices
(C) 10 edges and 5 vertices
(D) 10 edges and 6 vertices
View/Hide Ans
Correct Answer is B
5. Consider the DAG with V={1,2,3,4,5,6}, shown below.
6. Which of the following problems is undecidable?
(A) Membership problem for CFGs
(B) Ambiguity problem for CFGs
(C) Finiteness problem for FSAs.
(D) Equivalence problem for FSAs.
View/Hide Ans
Correct Answer is B
7. Which of the following is TRUE?
(A) Every subset of a regular set is regular.
(B) Every finite subset of a non-regular set is regular.
(C) The union of two non-regular sets is not regular.
(D) Infinite union of finite sets is regular.
View/Hide Ans
Correct Answer is B
8. How many 3-to-8 line decoders with an enable input are needed to construct a 6-
to-64 line decoder without using any other logic gates?
(A) 7
(B) 8
(C) 9
(D) 10
View/Hide Ans
Correct Answer is C
9. Consider the following Boolean function of four variables:
f (w, x, y, z) = ∑(1,3,4,6,9,11,12,14).
The function is:
(A) independent of one variables.
(B) independent of two variables.
(C) independent of three variables.
(D) dependent on all the variables.
View/Hide Ans
Correct Answer is B
10. Consider a 4-way set associative cache consisting of 128 lines with a line size of
64 words. The CPU generates a 20-bit address of a word in main memory. The
number of bits in the TAG, LINE and WORD fields are respectively:
(A) 9, 6, 5
(B) 7, 7, 6
(C) 7, 5, 8
(D) 9, 5, 6
View/Hide Ans
Correct Answer isD
11. Consider a disk pack with 16 surfaces, 128 tracks per surface and 256 sectors
per track. 512 bytes of data are stored in a bit serial manner in a sector. The
capacity of the disk pack and the number of bits required to specify a particular
sector in the disk are respectively:
(A) 256 Mbyte, 19 bits
(B) 256 Mbyte, 28 bits
(C) 512 Mbyte, 20 bits
(D) 64 Gbyte, 28 bits
View/Hide Ans
Correct Answer is A
12. The height of a binary tree is the maximum number of edges in any root to leaf
path. The maximum number of nodes in a binary tree of height h is:
(A) 2h -1
(B) 2h-1 -1
(C) 2h+1 -1
(D) 2h+1
View/Hide Ans
Correct Answer is C
13. The maximum number of binary trees that can be formed with three unlabeled
nodes is:
(A) 1
(B) 5
(C) 4
(D) 3
View/Hide Ans
Correct Answer is B
14. Which of the following sorting algorithms has the lowest worst-case complexity?
(A) Merge sort
(B) Bubble sort
(C) Quick sort
(D) Selection sort
View/Hide Ans
Correct Answer is A
15. Consider the following segment of C-code:
int j, n;
j = 1;
while (j <=n)
j = j*2;
The number of comparisons made in the execution of the loop for any n > 0 is:
(A) ⌈log2 n⌉+1
(B) n
(C) ⌈log2n ⌉
(D) ⌊log2 n⌋+1
View/Hide Ans
Correct Answer is D
16. Group 1 contains some CPU scheduling algorithms and Group 2 contains some
applications. Match entries in Group 1 to entries in Group 2.
Codes:
Group I
Group II
(P) Gang Scheduling
(1) Guaranteed Scheduling
(Q) Rate Monotonic Scheduling
(2) Real-time Scheduling
(R) Fair Share Scheduling
(3) Thread Scheduling
(A) P - 3 Q - 2 R - 1
(B) P - 1 Q - 2 R - 3
(C) P - 2 Q - 3 R - 1
(D) P - 1 Q - 3 R - 2
View/Hide Ans
Correct Answer is A
17. Consider the following statements about user level threads and kernel level
threads. Which one of the following statements is FALSE?
(A) Context switch time is longer for kernel level threads than for user level
threads.
(B) User level threads do not need any hardware support.
(C) Related kernel level threads can be scheduled on different processors in a
multi-processor system.
(D) Blocking one kernel level thread blocks all related threads.
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Correct Answer is D
18. Which one of the following is a top-down parser?
(A) Recursive descent parser.
(B) Operator precedence parser.
(C) An LR(k) parser.
(D) An LALR(k) parser.
View/Hide Ans
Correct Answer is A
19. In Ethernet when Manchester encoding is used, the bit rate is:
(A) Half the baud rate
(B) Twice the baud rate.
(C) Same as the baud rate.
(D) None of the above
View/Hide Ans
Correct Answer is A
20. Which one of the following uses UDP as the transport protocol?
(A) HTTP
(B) Telnet
(C) DNS
(D) SMTP
View/Hide Ans
Correct Answer is C
21. How many different non-isomorphic Abelian groups of order 4 are there?
(A) 2
(B) 3
(C) 4
(D) 5
View/Hide Ans
Correct Answer is A
22. Let Graph(x) be a predicate which denotes that x is a graph. Let Connected(x) be
a predicate which denotes that x is connected. Which of the following first order
logic sentences DOES NOT represent the statement: “Not every graph is
connected” ?
(A) ∼∀x(Graph(x)⇒Connected(x))
(B) ∃x(Graph(x)∧∼Connected(x))
(C) ∼∀x(∼Graph(x)∨Connected(x))
(D) ∀x(Graph(x)⇒ ∼Connected(x))
View/Hide Ans
Correct Answer is D
23. Which of the following graphs has an Eulerian circuit?
(A) Any k-regular graph where k is an even number.
(B) A complete graph on 90 vertices.
(C) The complement of a cycle on 25 vertices.
(D) None of the above.
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Correct Answer is C
24. Suppose we uniformly & randomly select a permutation from the 20! permutations of 1, 2,3 ,…..,20. What is the probability that 2 appears at an
earlier position than any other even number in the selected permutation?
(A) 1/2
(B) 1/10
(C) 9!/20!
(D) None of these
View/Hide Ans
Correct Answer is D
25. Let A be a 4 × 4 matrix with eigenvalues -5, -2, 1, 4. Which of the following is an
eigenvalue of ,
where I is the 4 × 4 identity matrix?
(A) -5
(B) -7
(C) 2
(D) 1
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Correct Answer is C
26. Consider the set S = {a,b,c,d}. Consider the following 4 partitions ∏1, ∏2 ,∏3 ,∏4 on
S:
∏1={(abcd)'}
∏2={(ab)',(cd)'}
∏3={(abc)',(d)'}
∏2={a',b',c',d'}.
Let p be the partial
order on the set of partitions S'={∏1, ∏2 ,∏3 ,∏4} defined as follows: ∏i < ∏j
if and only if ∏i refines ∏j. The poset diagram for (S',<) is:
27. Consider the set of (column) vectors defined by
X={x∈R3 | x1+x2+x3=0, where xT=[x1+,2,x3]}T
Which of the following is
TRUE?
(A) {[1,-1,0]T , [1,0,-1]T } is a basis for the subspace X
(B) {[1,-1,0]T , [1,0,-1]T } is a linearlyindependent set, but it does not span X and therefore is not a basis of X.
(C) X is not a subspace of R3
(D) None of the above
View/Hide Ans
Correct Answer is A
28. Consider the series xn+1=(xn/2)+(9/ 8xn), x0= 0.5 obtained from the Newton-Raphson
method. The series converges to
(A) 1.5
(B) √2
(C) 1.6
(D) 1.4
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Correct Answer is A
29. A minimum state deterministic finite automaton accepting the language
L={w|w ∈ {0,1}*, number of 0's and 1's in w are divisible
by 3 and 5 respectively} has
(A) 15 states
(B) 11 states
(C) 10 states
(D) 9 states
View/Hide Ans
Correct Answer is A
30. The language L={0i 21i | i≥0}
over the alphabet {0, 1, 2} is
(A) not recursive
(B) is recursive and is a deterministic CFL.
(C) is a regular language.
(D) is not a deterministic CFL but a CFL.
View/Hide Ans
Correct Answer is B
31. Which of the following languages is regular?
(A) {wwR | w ∈ {0,1}+}
(B) {wwR x | x, w ∈ {0,1}+}
(C) {wxwR | x, w ∈ {0,1}+}
(D) {xwwR | x, w ∈ {0,1}+}
View/Hide Ans
Correct Answer is C
32. Let f (w, x, y, z) = Σ(0,4,5,7,8,9,13,15). Which of the following expressions are NOT equivalent to f ?
(p) x'y'z'+ w'xy'+ wy'z + xz (q) w'y'z' + wx'y' + xz (r) w'y'z' + wx'y' + xyz + xy'z (s) x'y'z' + wx'y' + w'y
(A) p only 33. Define the connective * for the Boolean variables X and Y as: X*Y= XY + X'Y'
Let Z = X *Y. Consider the following expressions P, Q and R.
P: X=Y*Z, Q:Y=X*Z , R:X*Y*Z=1
(A) Only P and Q are valid.
(B) Only Q and R are valid.
(C) Only P and R are valid.
(D) All P, Q, R are valid.
View/Hide Ans
Correct Answer is D
34. Suppose only one multiplexer and one inverter are allowed to be used to
implement any Boolean function of n variables. What is the minimum size of the
multiplexer needed?
(A) 2n line to 1 line
(B) 2n+1 line to 1 line
(C) 2n-1 line to 1 line
(D) 2n-2 line to 1 line
View/Hide Ans
Correct Answer is C
35. In a look-ahead carry generator, the carry generate function Gi and the carry
propagate function Pi for inputs Ai and Bi are given by:
Pi= Ai⊕Bi and Gi= AiBi
The expressions for the sum bit Si and the carry bit Ci+1 of the look-ahead carry
adder are given by:
Si= Pi⊕Ci and Ci+1= Gi+PiCi, where c0 is the input carry.
Consider a two-level logic implementation of the look-ahead carry generator.
Assume that all Pi and Gi are available for the carry generator circuit and that
the AND and OR gates can have any number of inputs. The number of AND gates
and OR gates needed to implement the look-ahead carry generator for a 4-bit
adder with S3,S2,S1,S0 and C0 as its outputs are respectively
(A) 6, 3
(B) 10, 4
(C) 6, 4
(D) 10, 5
View/Hide Ans
Correct Answer is B
36. The control signal functions of a 4-bit binary counter are given below (where X is
“don’t care”):
37. Consider a pipelined processor with the following four stages:
IF: Instruction Fetch
ID: Instruction Decode and Operand Fetch
EX: Execute
WB: Write Back
The IF, ID and WB stages take one clock cycle each to complete the operation.
The number of clock cycles for the EX stage depends on the instruction. The ADD
and SUB instructions need 1 clock cycle and the MUL instruction needs 3 clock
cycles in the EX stage. Operand forwarding is used in the pipelined processor.
What is the number of clock cycles taken to complete the following sequence of
instructions?
ADD R2, R1, R0 R2 <-- R1 + R0
MUL R4, R3, R2 R4 <-- R3 * R2
SUB R6, R5, R4 R6 <-- R5 - R4
(A) 7
(B) 8
(C) 10
(D) 14
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Correct Answer is B
38. The following postfix expression with single digit operands is evaluated using a
stack:
8 2 3 ∧/ 2 3 * + 5 1 * -
Note that ∧ is the exponentiation operator. The top two elements of the stack
after the first * is evaluated are:
(A) 6, 1
(B) 5, 7
(C) 3, 2
(D) 1, 5
View/Hide Ans
Correct Answer is A
39. The inorder and preorder traversal of a binary tree are
"d b e a f c g" and "a b d e c f g" , respectively
The postorder traversal of the binary tree is:
(A) d e b f g c a
(B) e d b g f c a
(C) e d b f g c a
(D) d e f g b c a
View/Hide Ans
Correct Answer is A
40. Consider a hash table of size seven, with starting index zero, and a hash function
(3x + 4)mod7. Assuming the hash table is initially empty, which of the following
is the contents of the table when the sequence 1, 3, 8, 10 is inserted into the
table using closed hashing? Note that − denotes an empty location in the table.
(A) 8, −, −, −, −, −, 10
(B) 1, 8, 10, −, −, −, 3
(C) 1, −, −, −, −, −, 3
(D) 1, 10, 8, −, −, −, 3
View/Hide Ans
Correct Answer is B
41. In an unweighted, undirected connected graph, the shortest path from a node S
to every other node is computed most efficiently, in terms of time complexity, by
(A) Dijkstra’s algorithm starting from S.
(B) Warshall’s algorithm
(C) Performing a DFS starting from S.
(D) Performing a BFS starting from S.
View/Hide Ans
Correct Answer is D
42. Consider the following C function:
int f(int n)
{static int r = 0;
if (n <= 0) return 1;
if (n > 3)
{ r = n;
return f(n-2)+2;
}
return f(n-1)+r;
}
What is the value of f(5)?
(A) 5
(B) 7
(C) 9
(D) 18
View/Hide Ans
Correct Answer is D
43. A complete n-ary tree is a tree in which each node has n children or no children.
Let I be the number of internal nodes and L be the number of leaves in a
complete n-ary tree. If L = 41, and I = 10, what is the value of n?
(A) 3
(B) 4
(C) 5
(D) 6
View/Hide Ans
Correct Answer is C
44. In the following C function, let n>=m.
int gcd(n,m)
{
if (n%m ==0) return m;
n = n%m;
return gcd(m,n);
}
How many recursive calls are made by this function?
(A) Θ(log2n)
(B) Ω(n)
(C) Θ(log2 log2n)
(D) Θ(√n)
View/Hide Ans
Correct Answer is A
45. What is the time complexity of the following recursive function:
int DoSomething (int n) {
if (n <= 2)
return 1;
else
return (DoSomething (floor(sqrt(n))) + n);
}
(A) Θ(n2)
(B) Θ(nlog2n)
(C) Θ(log2n)
(D) Θ(log2 log2n)
View/Hide Ans
Correct Answer is D
46. Consider the following C program segment where CellNode represents a node in a
binary tree:
struct CellNode {
struct CellNOde *leftChild;
int element;
struct CellNode *rightChild;
};
int GetValue (struct CellNode *ptr) {
int value = 0;
if (ptr != NULL) {
if ((ptr->leftChild == NULL) && (ptr->rightChild == NULL))
value = 1;
else
value = value + GetValue(ptr->leftChild)
}
return(value);
}
The value returned by GetValue when a pointer to the root of a binary tree is
passed as its argument is:
(A) the number of nodes in the tree
(B) the number of internal nodes in the tree
(C) the number of leaf nodes in the tree
(D) the height of the tree
View/Hide Ans
Correct Answer is C
47. Consider the process of inserting an element into a Max Heap, where the Max
Heap is represented by an array. Suppose we perform a binary search on the
path from the new leaf to the root to find the position for the newly inserted
element, the number of comparisons performed is:
(A) Θ(log2n)
(B) Θ(log2log2n)
(C) Θ(n)
(D) Θ(nlog2n)
View/Hide Ans
Correct Answer is B
48. Which of the following is TRUE about formulae in Conjunctive Normal Form?
(A) For any formula, there is a truth assignment for which at least half the
clauses evaluate to true.
(B) For any formula, there is a truth assignment for which all the clauses
evaluate to true.
(C) There is a formula such that for each truth assignment, at most one-fourth of
the clauses evaluate to true.
(D) None of the above.
View/Hide Ans
Correct Answer is A
49. Let w be the minimum weight among all edge weights in an undirected connected
graph. Let e be a specific edge of weight w . Which of the following is FALSE?
(A) There is a minimum spanning tree containing e.
(B) If e is not in a minimum spanning tree T, then in the cycle formed by adding
e to T, all edges have the same weight.
(C) Every minimum spanning tree has an edge of weight w .
(D) e is present in every minimum spanning tree.
View/Hide Ans
Correct Answer is D
50. An array of n numbers is given, where n is an even number. The maximum as
well as the minimum of these n numbers needs to be determined. Which of the
following is TRUE about the number of comparisons needed?
(A) At least 2n−c comparisons, for some constant c, are needed.
(B) At most 1.5n−2 comparisons are needed.
(C) At least nlog2n comparisons are needed.
(D) None of the above.
View/Hide Ans
Correct Answer is B
51. Consider the following C code segment:
int IsPrime(n)
{
int i,n;
for(i=2;i<=sqrt(n);i++)
if(n%i == 0)
{printf(“Not Prime\n”); return 0;}
return 1;
}
Let T (n)denote the number of times the for loop is executed by the program on
input n. Which of the following is TRUE?
(A) T(n)= O(√n) and T(n)= Ω(√n)
(B) T(n)= O(√n) and T(n)= Ω(1)
(C) T(n)= O(n) and T(n)= Ω(√n)
(D) None of the above
View/Hide Ans
Correct Answer is B
52. Consider the grammar with non-terminals N={S,C,S1}, terminals
T={a,b,i,t,e} with S as the start symbol, and the following set of rules:
S → iCtSS1|a
S1 → eS|ε
C → b
The grammar is NOT LL(1) because:
(A) it is left recursive
(B) it is right recursive
(C) it is ambiguous
(D) it is not context-free
View/Hide Ans
Correct Answer is C
53. Consider the following two statements:
P: Every regular grammar is LL(1)
Q: Every regular set has a LR(1) grammar
Which of the following is TRUE?
(A) Both P and Q are true
(B) P is true and Q is false
(C) P is false and Q is true
(D) Both P and Q are false
View/Hide Ans
Correct Answer is C
54. In a simplified computer the instructions are:
OP Rj ,Ri - Performs Rj OP Ri and stores the result in register Ri
OP m, Rj - Performs val OP Ri and stores the result in Ri val
denotes the content of memory location m.
MOV m, Rj - Moves the content of memory location m to register Ri
MOV Rj, m - Moves the content of register Ri to memory location m.
The computer has only to registers, and OP is either ADD or SUB. Consider the
following basic block:
t1=a+b
t2=c+d
t3=e-t2
t4=t1-t3
Assume that all operands are initially in memory. The final value of the
computation should be in memory. What is the minimum number of MOV
instructions in the code generated for this basic block?
(A) 2
(B) 3
(C) 5
(D) 6
View/Hide Ans
Correct Answer is B
55. An operating system uses Shortest Remaining Time first (SRT) process
scheduling algorithm. Consider the arrival times and execution times for the
following processes:
What is the total waiting time for process P2?
Process
Execution time
Arrival time
P1
20
0
P2
25
15
P3
10
30
P4
15
45
(A) 5
(B) 15
(C) 40
(D) 55
View/Hide Ans
Correct Answer is B
56. A virtual memory system uses First In First Out (FIFO) page replacement policy
and allocates a fixed number of frames to a process. Consider the following
statements:
P: Increasing the number of page frames allocated to a process sometimes
increases the page fault rate.
Q: Some programs do not exhibit locality of reference.
Which one of the following is TRUE?
(A) Both P and Q are true, and Q is the reason for P
(B) Both P and Q are true, but Q is not the reason for P.
(C) P is false, but Q is true
(D) Both P and Q are false.
View/Hide Ans
Correct Answer is B
57. A single processor system has three resource types X, Y and Z, which are shared
by three processes. There are 5 units of each resource type. Consider the
following scenario, where the column "alloc" denotes the number of units of each
resource type allocated to each process, and the column "request" denotes the
number of units of each resource type requested by a process in order to
complete execution. Which of these processes will finish "LAST"?
58. Two processes, P1 and P2, need to access a critical section of code. Consider the
following synchronization construct used by the processes:
59. Information about a collection of students is given by the relation
studinfo(studId, name, sex). The relation enroll(studId, courseId) gives which
student has enrolled for (or taken) what course(s). Assume that every course is
taken by at least one male and at least one female student. What does the
following relational algebra expression represent?
πcourseId(( πstudId(σsex="female" (studInfo)) * πcourseId(enroll)) - enroll)
(A) Courses in which all the female students are enrolled
(B) Courses in which a proper subset of female students are enrolled.
(C) Courses in which only male students are enrolled.
(D) None of the above
View/Hide Ans
Correct Answer is B
60. Consider the relation employee(name, sex, supervisorName) with name as the
key. supervisorName gives the name of the supervisor of the employee under
consideration. What does the following Tuple Relational Calculus query produce?
{e.name|employee(e) ∧
(∀ x)[∼ employee(x) ∨ x.supervisorName ≠ e.name ∨ x.sex="male"]}
(A) Names of employees with a male supervisor.
(B) Names of employees with a male supervisor.
(C) Names of employees with no immediate female subordinates.
(D) Names of employees with a female supervisor.
View/Hide Ans
Correct Answer is C
61. Consider the table employee(empId, name, department, salary) and the two
queries Q1 ,Q2 below.
Assuming that department 5 has more than one employee,
and we want to find the employees who get higher salary than anyone in the
department 5, which one of the statements is TRUE for any arbitrary employee
table?
Q1 : Select e.empId
From employee e
Where not exists
(Select * From employee s where s.department = “5” and s.salary >=e.salary)
Q2 : Select e.empId
From employee e
Where e.salary > Any
(Select distinct salary From employee s Where s.department = “5”)
(A) Q1 is the correct query
(B) Q2 is the correct query
(C) Both Q1 and Q2 produce the same answer.
(D) Neither Q1 nor Q2 is the correct query.
View/Hide Ans
Correct Answer is D
62. Which one of the following statements if FALSE?
(A) Any relation with two attributes is in BCNF
(B) A relation in which every key has only one attribute is in 2NF
(C) A prime attribute can be transitively dependent on a key in a 3NF relation.
(D) A prime attribute can be transitively dependent on a key in a BCNF relation.
View/Hide Ans
Correct Answer isD
63. The order of a leaf node in a B+-tree is the maximum number of (value, data
record pointer) pairs it can hold. Given that the block size is 1K bytes, data
record pointer is 7 bytes long, the value field is 9 bytes long and a block pointer
is 6 bytes long, what is the order of the leaf node?
(A) 63
(B) 64
(C) 67
(D) 68
View/Hide Ans
Correct Answer is A
64. Consider the following schedules involving two transactions. Which one of the
following statements is TRUE?
S1:r1(X); r1(Y); r2(X); r2(Y); w2(Y); w1(X)
S2:r1(X); r2(X); r2(Y); w2(Y); r1(Y); w1(X)
(A) Both S1 and S2 are conflict serializable.
(B) S1 is conflict serializable and S2 is not conflict serializable.
(C) S1is not conflict serializable and S2 is conflict serializable.
(D) Both S1 and S2 are not conflict serializable.
View/Hide Ans
Correct Answer is C
65. There are n stations in a slotted LAN. Each station attempts to transmit with a
probability p in each time slot. What is the probability that ONLY one station
transmits in a given time slot?
(A) np(1-p)n-1
(B) (1-p)n-1
(C) p(1-p)n-1
(D) 1-(1-p)n-1
View/Hide Ans
Correct Answer is B
66. In a token ring network the transmission speed is 107 bps and the propagation
speed is 200 metres/μs. The 1-bit delay in this network is equivalent to:
(A) 500 metres of cable.
(B) 200 metres of cable.
(C) 20 metres of cable.
(D) 50 metres of cable.
View/Hide Ans
Correct Answer is C
67. The address of a class B host is to be split into subnets with a 6-bit subnet
number. What is the maximum number of subnets and the maximum number of
hosts in each subnet?
(A) 62 subnets and 262142 hosts.
(B) 64 subnets and 262142 hosts
(C) 62 subnets and 1022 hosts.
(D) 64 subnets and 1024 hosts.
View/Hide Ans
Correct Answer is C
68. The message 11001001 is to be transmitted using the CRC polynomial x3 + 1 to
protect it from errors. The message that should be transmitted is:
(A) 11001001000
(B) 11001001011
(C) 11001010
(D) 110010010011
View/Hide Ans
Correct Answer is B
69. Match the following:
codes:
List I
List II
(P) SMTP
(1) Application layer
(Q) BGP
(2) Transport layer
(R) TCP
(3) Data link layer
(S) PPP
(4) Network layer
(5) Physical layer
(A) P-2 Q-1 R-3 S-5
(B) P-1 Q-4 R-2 S-3
(C) P-1 Q-4 R-2 S-5
(D) P-2 Q-4 R-1 S-3
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Correct Answer is C
70. The distance between two stations M and N is L kilometers. All frames are K bits
long. The propagation delay per kilometer is t seconds. Let R bits/second be the
channel capacity. Assuming that processing delay is negligible, the minimum
number of bits for the sequence number field in a frame for maximum utilization,
when the sliding window protocol is used, is:
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Correct Answer is B
71. Consider the following program segment. Here R1, R2 and R3 are the general purpose
registers.
72. Consider the following program segment. Here R1, R2 and R3 are the general purpose
registers.
73. Consider the following program segment. Here R1, R2 and R3 are the general purpose
registers.
Assume that the content of memory location 3000 is 10 and the content of the register
R3 is 2000. The content of each of the memory locations from 2000 to 2010 is 100. The
program is loaded from the memory location 1000. All the numbers are in decimal.
Assume that the memory is byte addressable and the word size is 32 bits. If an
interrupt occurs during the execution of the instruction “INC R3”, what return
address will be pushed on to the stack?
(A) 1005
(B) 1020
(C) 1024
(D) 1040
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Correct Answer is C
74. Consider the following Finite State Automaton:
75. Consider the following Finite State Automaton:
76. Suppose the letters a, b, c, d, e, f have probabilities
1/2, 1/4, 1/8, 1/16, 1/32, 1/32
respectively
Which of the following is the Huffman code for the letter a, b, c, d, e, f?
(A) 0, 10, 110, 1110, 11110, 11111
(B) 11, 10, 011, 010, 001, 000
(C) 11, 10, 01, 001, 0001, 0000
(D) 110, 100, 010, 000, 001, 111
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Correct Answer is A
77. Suppose the letters a, b, c, d, e, f have probabilities
1/2, 1/4, 1/8, 1/16, 1/32, 1/32
respectively
What is the average length of the correct answer to Q.76?
(A) 3
(B) 2.1875
(C) 2.25
(D) 1.9375
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Correct Answer is D
78. Consider the CFG with {S, A,B} as the non-terminal alphabet, {a,b}as the terminal
alphabet, S as the start symbol and the following set of production rules:
S → aB S → bA
B → b A → a
B → bS A → aS
B → aBB ` S →bAA
Which of the following strings is generated by the grammar?
(A) aaaabb
(B) aabbbb
(C) aabbab
(D) abbbba
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Correct Answer is C
79. Consider the CFG with {S, A,B} as the non-terminal alphabet, {a,b}as the terminal
alphabet, S as the start symbol and the following set of production rules:
S → aB S → bA
B → b A → a
B → bS A → aS
B → aBB S →bAA
For the correct answer strings to Q.78, how many derivation trees are there?
(A) 1
(B) 2
(C) 3
(D) 4
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Correct Answer is B
80. Consider a machine with a byte addressable main memory of 216 bytes. Assume that a
direct mapped data cache consisting of 32 lines of 64 bytes each is used in the system.
A 50 × 50 two-dimensional array of bytes is stored in the main memory starting from
memory location 1100H. Assume that the data cache is initially empty. The complete
array is accessed twice. Assume that the contents of the data cache do not change in
between the two accesses.
How many data cache misses will occur in total?
(A) 48
(B) 50
(C) 56
(D) 59
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Correct Answer is C
81. Consider a machine with a byte addressable main memory of 216 bytes. Assume that a
direct mapped data cache consisting of 32 lines of 64 bytes each is used in the system.
A 50 × 50 two-dimensional array of bytes is stored in the main memory starting from
memory location 1100H. Assume that the data cache is initially empty. The complete
array is accessed twice. Assume that the contents of the data cache do not change in
between the two accesses.
Which of the following lines of the data cache will be replaced by new blocks in
accessing the array for the second time?
(A) line 4 to line 11
(B) line 4 to line 12
(C) line 0 to line 7
(D) line 0 to line 8
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Correct Answer is A
82. A process has been allocated 3 page frames. Assume that none of the pages of the
process are available in the memory initially. The process makes the following sequence
of page references (reference string): 1, 2, 1, 3, 7, 4, 5, 6, 3, 1
If optimal page replacement policy is used, how many page faults occur for the
above reference string?
(A) 7
(B) 8
(C) 9
(D) 10
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Correct Answer is A
83. A process has been allocated 3 page frames. Assume that none of the pages of the
process are available in the memory initially. The process makes the following sequence
of page references (reference string): 1, 2, 1, 3, 7, 4, 5, 6, 3, 1
Least Recently Used (LRU) page replacement policy is a practical approximation
to optimal page replacement. For the above reference string, how many more
page faults occur with LRU than with the optimal page replacement policy?
(A) 0
(B) 1
(C) 2
(D) 3
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Correct Answer is C
84. Suppose that a robot is placed on the Cartesian plane. At each step it is allowed to move
either one unit up or one unit right, i.e., if it is at (i, j ) then it can move to either
(i + 1, j ) or (i, j + 1).
How many distinct paths are there for the robot to reach the point (10,10) starting from the initial position (0, 0)
(A) 20C10
(B) 220
(C) 210
(D) None of the above
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Correct Answer is A
85. Suppose that a robot is placed on the Cartesian plane. At each step it is allowed to move
either one unit up or one unit right, i.e., if it is at (i, j ) then it can move to either
(i + 1, j ) or (i, j + 1).
Suppose that the robot is not allowed to traverse the line segment from (4,4) to
(5,4). With this constraint, how many distinct paths are there for the robot to
reach (10,10) starting from (0,0)?
(A) 29
(B) 219
(C) 8C4*11C5
(D) 20C10-8C5*11C5
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Correct Answer is D
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