50. Which of the following is not the type of queue?
a) Ordinary queue
b) Single ended queue
c) Circular queue
d) Priority queue
Answer: b
Explanation: Queue always has two ends. So, single ended queue is not the type of queue.
Author: Wajahat Shah
49. Queues serve major role in __
a) Simulation of recursion
b) Simulation of arbitrary linked list
c) Simulation of limited resource allocation
d) Simulation of heap sort
Answer: c
Explanation: Simulation of recursion uses stack data structure. Simulation of arbitrary linked lists uses linked lists. Simulation of resource allocation uses queue as first entered data needs to be given first priority during resource allocation. Simulation of heap sort uses heap data structure.
48. A normal queue, if implemented using an array of size MAX_SIZE, gets full when?
a) Rear = MAX_SIZE – 1
b) Front = (rear + 1)mod MAX_SIZE
c) Front = rear + 1
d) Rear = front
Answer: a
Explanation: When Rear = MAX_SIZE – 1, there will be no space left for the elements to be added in queue. Thus queue becomes full.
47. A data structure in which elements can be inserted or deleted at/from both ends but not in the middle is?
a) Queue
b) Circular queue
c) Dequeue
d) Priority queue
Answer: c
Explanation: In dequeuer, we can insert or delete elements from both the ends. In queue, we will follow first in first out principle for insertion and deletion of elements. Element with least priority will be deleted in a priority queue.
46. If the elements “A”, “B”, “C” and “D” are placed in a queue and are deleted one at a time, in what order will they be removed?
a) ABCD
b) DCBA
c) DCAB
d) ABDC
Answer: a
Explanation: Queue follows FIFO approach. i.e. First in First Out Approach. So, the order of removal elements are ABCD.
45. Circular Queue is also known as __
a) Ring Buffer
b) Square Buffer
c) Rectangle Buffer
d) Curve Buffer
Answer:a
Explanation: Circular Queue is also called as Ring Buffer. Circular Queue is a linear data structure in which last position is connected back to the first position to make a circle. It forms a ring structure.
44. A queue follows __
a) FIFO (First In First Out) principle
b) LIFO (Last In First Out) principle
c) Ordered array
d) Linear tree
Answer: a
Explanation: Element first added in queue will be deleted first which is FIFO principle.
43. The data structure required for Breadth First Traversal on a graph is?
a) Stack
b) Array
c) Queue
d) Tree
Answer: c
Explanation: In Breadth First Search Traversal, BFS, starting vertex is first taken and adjacent vertices which are unvisited are also taken. Again, the first vertex which was added as an unvisited adjacent vertex list will be considered to add further unvisited vertices of the graph. To get the first unvisited vertex we need to follows First In First Out principle. Queue uses FIFO principle.
42. A linear list of elements in which deletion can be done from one end (front) and insertion can take place only at the other end (rear) is known as _
a) Queue
b) Stack
c) Tree
d) Linked list
Answer: a
Explanation: Linear list of elements in which deletion is done at front side and insertion at rear side is called Queue. In stack we will delete the last entered element first.
41. If the elements “A”, “B”, “C” and “D” are placed in a stack and are deleted one at a time, what is the order of removal?
a) ABCD
b) DCBA
c) DCAB
d) ABDC
Answer: b
Explanation: Stack follows LIFO(Last In First Out). So the removal order of elements are DCBA.
40. Assume that the operators +,-, X are left associative and ^ is right associative. The order of precedence (from highest to lowest) is ^, X, +, -. The postfix expression for the infix expression a + b X c – d ^ e ^ f is?
a) abc X+ def ^^ –
b) abc X+ de^f^ –
c) ab+c Xd – e ^f^
d) -+aXbc^ ^def
Answer: b
Explanation: Given Infix Expression is a + b X c – d ^ e ^ f.
(a b c X +) (d ^ e ^ f). ‘–‘ is present in stack.
(a b c X + d e ^ f ^ -). Thus the final expression is (a b c X + d e ^ f ^ -)
39. The type of expression in which operator succeeds its operands is?
a) Infix Expression
b) Prefix Expression
c) Postfix Expression
d) Both Prefix and Postfix Expressions
Answer: c
Explanation: The expression in which operator succeeds its operands is called postfix expression. The expression in which operator precedes the operands is called prefix expression. If an operator is present between two operands, then it is called infix expressions.
38. Which of the following is not an inherent application of stack?
a) Reversing a string
b) Evaluation of postfix expression
c) Implementation of recursion
d) Job scheduling
Answer: d
Explanation: Job Scheduling is not performed using stacks.
37. Consider the following operation performed on a stack of size
Push(1);
Pop();
Push(2);
Push(3);
Pop();
Push(4);
Pop();
Pop();
Push(5);
After the completion of all operation, the number of elements present in stack is?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: Number of elements present in stack is equal to the difference between number of push operations and number of pop operations. Number of elements is 5-4=1.
36. Which of the following statement(s) about stack data structure is/are NOT correct?
a) Linked List are used for implementing Stacks
b) Top of the Stack always contain the new node
c) Stack is the FIFO data structure
d) Null link is present in the last node at the bottom of the stack
Answer: c
Explanation: Stack follows LIFO.
35. Convert the following Infix expression to Postfix form using a stack.
x + y * z + (p * q + r) * s, Follow usual precedence rule and assume that the expression is legal.
a) xyz+pqr+s+
b) xyz+pqr+s+
c) xyz+pqr+s+
d) xyzp+qr+s+
Answer: a
Explanation: The Infix Expression is x + y * z + (p * q + r) * s.
(x y z ) + (p * q + r) * s. ‘+’, ‘*’ are present in stack.
(x y z * + p q * r) * s. ‘+’ is present in stack.
x y z * + p q * r + s * +. Thus Postfix Expression is x y z * + p q * r + s * +.
34. Convert the following infix expressions into its equivalent postfix expressions.
(A + B ⋀D)/(E – F)+G
a) (A B D ⋀ + E F – / G +)
b) (A B D +⋀ E F – / G +)
c) (A B D ⋀ + E F/- G +)
d) (A B D E F + ⋀ / – G +)
Answer: a
Explanation: The given infix expression is (A + B ⋀D)/(E – F)+G.
(A B D ^ + ) / (E – F) +G
(A B D ^ + E F – ) + G. ‘/’ is present in stack.
A B D ^ + E F – / G +. Thus Postfix Expression is A B D ^ + E F – / G +.
33. The result of evaluating the postfix expression 5, 4, 6, +, *, 4, 9, 3, /, +, * is?
a) 600
b) 350
c) 650
d) 588
Answer: b
Explanation: The postfix expression is evaluated using stack. We will get the infix expression as
(5*(4+6))*(4+9/3). On solving the Infix Expression, we get
(5*(10))*(4+3)
= 50*7
= 350.
32. Which data structure is used for implementing recursion?
a) Queue
b) Stack
c) Array
d) List
Answer: b
Explanation: Stacks are used for the implementation of Recursion.
31. The prefix form of an infix expression (p + q) – (r * t) is?
a) + pq – *rt
b) – +pqr * t
c) – +pq * rt
d) – + * pqrt
Answer: c
Explanation: Given Infix Expression is ((p+q)-(r*t))
(+pq)-(r*t)
(-+pq)(r*t)
-+pq*rt. Thus prefix expression is -+pq*rt.
30. What is the result of the following operation?
Top (Push (S, X))
a) X
b) X+S
c) S
d) XS
Answer: a
Explanation: The function Push(S,X) pushes the value X in the stack S. Top() function gives the value which entered last. X entered into stack S at last.
29. The prefix form of A-B/ (C * D ^ E) is?
a) -/^ACBDE
b) -ABCD^DE
c) -A/BC^DE
d) -A/BC^DE
Answer: c
Explanation: Infix Expression is (A-B)/(C*D^E)
(-A/B)(C*D^E)
-A/B*C^DE. Thus prefix expression is -A/B*C^DE.
28. Which data structure is needed to convert infix notation to postfix notation?
a) Branch
b) Tree
c) Queue
d) Stack
Answer: d
Explanation: The Stack data structure is used to convert infix expression to postfix expression. The purpose of stack is to reverse the order of the operators in the expression. It also serves as a storage structure, as no operator can be printed until both of its operands have appeared.
27. The postfix form of A*B+C/D is?
a) AB/CD+
b) ABCD/+
c) ABC+/D
d) ABCD+/
Answer: b
Explanation: Infix expression is (A*B)+(C/D)
AB*+(C/D)
AB*CD/+. Thus postfix expression is AB*CD/+.
26. The process of accessing data stored in a serial access memory is similar to manipulating data on a __
a) Heap
b) Binary Tree
c) Array
d) Stack
Answer: d
Explanation: In serial access memory data records are stored one after the other in which they are created and are accessed sequentially. In stack data structure, elements are accessed sequentially. Stack data structure resembles the serial access memory.
25. What data structure would you mostly likely see in non recursive implementation of a recursive algorithm?
a) Linked List
b) Stack
c) Queue
d) Tree
Answer: b
Explanation: In recursive algorithms, the order in which the recursive process comes back is the reverse of the order in which it goes forward during execution. The compiler uses the stack data structure to implement recursion. In the forwarding phase, the values of local variables, parameters and the return address are pushed into the stack at each recursion level. In the backing-out phase, the stacked address is popped and used to execute the rest of the code.
24. The data structure required to check whether an expression contains a balanced parenthesis is?
a) Stack
b) Queue
c) Array
d) Tree
Answer: a
Explanation: The stack is a simple data structure in which elements are added and removed based on the LIFO principle. Open parenthesis is pushed into the stack and a closed parenthesis pops out elements till the top element of the stack is its corresponding open parenthesis. If the stack is empty, parenthesis is balanced otherwise it is unbalanced.
23. The postfix form of the expression (A+ B)(CD- E)*F / G is?
a) AB+ CDE – FG /*
b) AB + CD* E – F *G /
c) AB + CD E – *F *G /
d) AB + CDE * – * F *G /
Answer: c
Explanation: (((A+ B)*(C*D- E)*F) / G) is converted to postfix expression as
(AB+(*(C*D- E)*F )/ G)
(AB+CD*E-*F) / G
(AB+CD*E-*F * G/). Thus Postfix expression is AB+CD*E-*F*G/
22. Here is an infix expression: 4 + 3(63-12). Suppose that we are using the usual stack algorithm to convert the expression from infix to postfix notation. The maximum number of symbols that will appear on the stack AT ONE TIME during the conversion of this expression?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: When we perform the conversion from infix to postfix expression +, *, (, * symbols are placed inside the stack. A maximum of 4 symbols are identified during the entire conversion.
21. What is the value of the postfix expression 6 3 2 4 + – *?
a) 1
b) 40
c) 74
d) -18
Answer: d
Explanation: Postfix Expression is (6*(3-(2+4))) which results -18 as output.
20. Consider the usual algorithm for determining whether a sequence of parentheses is balanced. The maximum number of parentheses that appear on the stack AT ANY ONE TIME when the algorithm analyzes: (()(())(()))?
a) 1
b) 2
c) 3
d) 4 or more
Answer: b
Explanation: In the entire parenthesis balancing method when the incoming token is a left parenthesis it is pushed into stack. A right parenthesis makes pop operation to delete the elements in stack till we get left parenthesis as top most element. 3 elements are there in stack before right parentheses comes. Therefore, maximum number of elements in stack at run time is 3.
19. Which of the following is not the application of stack?
a) A parentheses balancing program
b) Tracking of local variables at run time
c) Compiler Syntax Analyzer
d) Data Transfer between two asynchronous process
Answer: d
Explanation: Data transfer between the two asynchronous process uses the queue data structure for synchronisation. The rest are all stack applications.
18. Entries in a stack are “ordered”. What is the meaning of this statement?
a) A collection of stacks is sortable
b) Stack entries may be compared with the ‘<‘ operation
c) The entries are stored in a linked list
d) There is a Sequential entry that is one by one
Answer: d
Explanation: In stack data structure, elements are added one by one using push operation. Stack follows LIFO Principle i.e. Last In First Out(LIFO).
17. Pushing an element into stack already having five elements and stack size of 5, then stack becomes _
a) Overflow
b) Crash
c) Underflow
d) User flow
Answer: a
Explanation: The stack is filled with 5 elements and pushing one more element causes a stack overflow. This results in overwriting memory, code and loss of unsaved work on the computer.
16. In a stack, if a user tries to remove an element from an empty stack it is called _
a) Underflow
b) Empty collection
c) Overflow
d) Garbage Collection
Answer: a
Explanation: Underflow occurs when the user performs a pop operation on an empty stack. Overflow occurs when the stack is full and the user performs a push operation. Garbage Collection is used to recover the memory occupied by objects that are no longer used.
15. Process of removing an element from stack is called __
a) Create
b) Push
c) Evaluation
d) Pop
Answer: d
Explanation: Elements in the stack are removed using pop operation. Pop operation removes the top most element in the stack i.e. last entered element.
14. Process of inserting an element in stack is called __
a) Create
b) Push
c) Evaluation
d) Pop
Answer: b
Explanation: Push operation allows users to insert elements in the stack. If the stack is filled completely and trying to perform push operation stack – overflow can happen.
13. Elements in an array are accessed _
a) randomly
b) sequentially
c) exponentially
d) logarithmically
Answer: a
Explanation: Elements in an array are accessed randomly. In Linked lists, elements are accessed sequentially.
12. In general, the index of the first element in an array is __
a) 0
b) -1
c) 2
d) 1
Answer: a
Explanation: In general, Array Indexing starts from 0. Thus, the index of the first element in an array is 0.
11. Assuming int is of 4bytes, what is the size of int arr[15];?
a) 15
b) 19
c) 11
d) 60
Answer: d
Explanation: Since there are 15 int elements and each int is of 4bytes, we get 15*4 = 60bytes.
10. What are the disadvantages of arrays?
a) Data structure like queue or stack cannot be implemented
b) There are chances of wastage of memory space if elements inserted in an array are lesser than the allocated size
c) Index value of an array can be negative
d) Elements are sequentially accessed
Answer: b
Explanation: Arrays are of fixed size. If we insert elements less than the allocated size, unoccupied positions can’t be used again. Wastage will occur in memory.
9. What are the advantages of arrays ?
a) Objects of mixed data types can be stored
b) Elements in an array cannot be sorted
c) Index of first element of an array is 1
d) Easier to store elements of same data type
Answer: d
Explanation: Arrays store elements of the same data type and present in continuous memory locations.
8. Which of the following concepts make extensive use of arrays ?
a) Binary trees
b) Scheduling of processes
c) Caching
d) Spatial locality
Answer: d
Explanation: Whenever a particular memory location is referred to, it is likely that the locations nearby are also referred, arrays are stored as contiguous blocks in memory, so if you want to access array elements, spatial locality makes it to access quickly.
7. When does the Array Index Out Of Bounds Exception occur?
a) Compile-time
b) Run-time
c) Not an error
d) Not an exception at all
Answer: b
Explanation: ArrayIndexOutOfBoundsException is a run-time exception and the compilation is error-free.
6. What is the output of the following Java code?
public class array
{
public static void main(String args[])
{
int []arr = {1,2,3,4,5};
System.out.println(arr[5]);
}
}
a) 4
b) 5
c) ArrayIndexOutOfBoundsException
d) InavlidInputException
Answer: c
Explanation: Trying to access an element beyond the limits of an array gives ArrayIndexOutOfBoundsException.
What is the output of the following Java code?
5. public class array
{
public static void main(String args[])
{
int []arr = {1,2,3,4,5};
System.out.println(arr[2]);
System.out.println(arr[4]);
}
}
a) 3 and 5
b) 5 and 3
c) 2 and 4
d) 4 and 2
Answer: a
Explanation: Array indexing starts from 0
4. Which of the following is the correct way to declare a multidimensional array in Java?
a) int[] arr;
b) int arr[[]];
c) int[][]arr;
d) int[[]] arr;
Answer: c
Explanation: The syntax to declare multidimensional array in java is either int[][] arr; or int arr[][];
3. How do you instantiate an array in Java?
a) int arr[] = new int(3);
b) int arr[];
c) int arr[] = new int[3];
d) int arr() = new int(3);
Answer: c
Explanation: Note that int arr[]; is declaration whereas int arr[] = new int[3]; is to instantiate an array.
2. How do you initialize an array in C?
a) int arr[3] = (1,2,3);
b) int arr(3) = {1,2,3};
c) int arr[3] = {1,2,3};
d) int arr(3) = (1,2,3);
Answer: c
Explanation: This is the syntax to initialize an array in C.
1. Which of these best describes an array?
a) A data structure that shows a hierarchical behavior
b) Container of objects of similar types
c) Arrays are immutable once initialised
d) Array is not a data structure
Answer: B
Explanation: Array contains elements only of the same type.
51. Which of the following statements can be associated with OSI model?
a) A structured way to discuss and easier update system components
b) One layer may duplicate lower layer functionality
c) Functionality at one layer no way requires information from another layer
d) It is an application specific network model
Answer: c
Explanation: One layer may use the information from another layer, for example timestamp value. The information is contained in the header inserted by the previous layer. The headers are added as the packet moves from higher layers to the lower layers.
50. In the OSI model, as a data packet moves from the lower to the upper layers, headers are _
a) Added
b) Removed
c) Rearranged
d) Randomized
Answer: b
Explanation: In OSI reference model, when data packet moves from lower layers to higher layer, headers get removed. Whereas when the data packet moves from higher layer to lower layers, headers are added. These headers contain the essential control information for the protocols used on the specific layer.
49. In TCP IP Model, when data is sent from device A to device B, the 5th layer to receive data at B is __
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: a
Explanation: In TCP/IP model, the fifth layer is application layer. When data is sent from device A to device B, the 5th layer to receive data at B is application layer. Application layer provides the interface between applications and the network. The user interacts with only this layer.
47. In OSI model, when data is sent from device A to device B, the 5th layer to receive data at B is _
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: d
Explanation: In OSI reference model, the fifth layer is Session layer. Session layer provides the mechanism for opening, closing and managing a session between end-user application processes. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
48. Delimiting and synchronization of data exchange is provided by __
a) Application layer
b) Session layer
c) Transport layer
d) Link layer
Answer: b
Explanation: The session layer provides the mechanism for opening, closing and managing a session between end-user application processes. The session layer 5 is responsible for establishing managing synchronizing and terminating sessions. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
46. The functionalities of the presentation layer include __
a) Data compression
b) Data encryption
c) Data description
d) All of the mentioned
Answer: d
Explanation: Some functions of the presentation layer include character-code translation, data conversion, data encryption and decryption, and data translation. It connects the application layer with the layers below converting the human readable text and media to machine readable format and vice-versa.
45. Transport layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Signal transmission
Answer:a
Explanation: Application, Presentation, Session and Transport layer are implemented in the end system. The transport layer handles the process to process delivery of the packet through ports.
44. Application layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Packet transport
Answer: a
Explanation: Not only application layer, but presentation layer, session layer and transport layer are also implemented in the end system. The layers below are implemented outside the end system, for example, the network layer is implemented on the routers and the physical layer is implemented for the medium.
43. Which of the following layers is an addition to OSI model when compared with TCP IP model?
a) Application layer
b) Presentation layer
c) Session layer
d) Session and Presentation layer
Answer: d
Explanation: The only difference between OSI model and TCP/IP model is that the functions of Presentation and Session layer in the OSI model are handled by the transport layer itself in TCP/IP. OSI is a generalized model and TCP/IP is an application specific model.
42. The number of layers in ISO OSI reference model is __
a) 5
b) 7
c) 6
d) 10
Answer: b
Explanation: The seven layers in ISO OSI reference model is Application, Presentation, Session, Transport, Network, Data link and Physical layer. OSI stands for Open System Interconnect and it is a generalized model.
41. How many layers are present in the Internet protocol stack (TCP/IP model)?
a) 5
b) 7
c) 6
d) 10
Answer: a
Explanation: There are five layers in the Internet Protocol stack. The five layers in Internet Protocol stack is Application, Transport, Network, Data link and Physical layer. The internet protocol stack model is also called the TCP/IP model and it’s used in modern Internet Communication.
40. Which of the following networks extends a private network across public networks?
a) local area network
b) virtual private network
c) enterprise private network
d) storage area network
Answer: b
Explanation: A virtual private network extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.VPN provides enhanced security and online anonymity to users on the internet. It is also used to unblock websites which are unavailable in certain regions.
39. Network congestion occurs _
a) in case of traffic overloading
b) when a system terminates
c) when connection between two nodes terminates
d) in case of transfer failure
Answer: a
Explanation: Network congestion occurs when traffic in the network is more than the network could handle. To avoid network congestion, the network management uses various open-loop and closed-loop congestion control techniques.
39. A list of protocols used by a system, one protocol per layer, is called __
a) protocol architecture
b) protocol stack
c) protocol suite
d) protocol system
Answer: b
Explanation: A protocol stack refers to a group of protocols that are running concurrently that are employed for the implementation of network protocol suite. Each layer in the network model has to use one specific protocol from the protocol stack.
38. A __ is a device that forwards packets between networks by processing the routing information included in the packet.
a) bridge
b) firewall
c) router
d) hub
Answer: c
Explanation: A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. They make use of routing protocols like RIP to find the cheapest path to the destination.
37. Bluetooth is an example of __
a) personal area network
b) local area network
c) virtual private network
d) wide area network
Answer: a
Explanation: Bluetooth is a wireless technology used to create a wireless personal area network for data transfer up to a distance of 10 meters. It operates on 2.45 GHz frequency band for transmission.
36. Communication channel is shared by all the machines on the network in __
a) broadcast network
b) unicast network
c) multicast network
d) anycast network
Answer: a
Explanation: In a broadcast network, information is sent to all stations in a network whereas in a multicast network the data or information is sent to a group of stations in the network. In unicast network, information is sent to only one specific station. The broadcast address of the network is the last assigned address of the network.
35. In computer network nodes are _
a) the computer that originates the data
b) the computer that routes the data
c) the computer that terminates the data
d) all of the mentioned
Answer: d
Explanation: In a computer network, a node can be anything that is capable of sending data or receiving data or even routing the data to its destination. Routers, Computers and Smartphones are some examples of network nodes.
34. Which of the following computer networks is built on the top of another network?
a) prior network
b) chief network
c) prime network
d) overlay network
Answer: d
Explanation: An overlay network is a computer network that is built on top of another network. Some examples of an overlay network are Virtual Private Networks (VPN) and Peer-to-Peer Networks (P2P).
33. Two devices are in network if __
a) a process in one device is able to exchange information with a process in another device
b) a process is running on both devices
c) PIDs of the processes running of different devices are same
d) a process is active and another is inactive
Answer: a
Explanation: A computer network, or data network, is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections between nodes. The nodes have certain processes which enable them to share a specific type of data using a distinct protocol.
32. When collection of various computers seems a single coherent system to its client, then it is called _
a) computer network
b) distributed system
c) networking system
d) mail system
Answer: b
Explanation: A Computer network is defined as a collection of interconnected computers which uses a single technology for connection.
A distributed system is also the same as computer network but the main difference is that the whole collection of computers appears to its users as a single coherent system.
Example:- World wide web
31. Which of the following statements can be associated with OSI model?
a) A structured way to discuss and easier update system components
b) One layer may duplicate lower layer functionality
c) Functionality at one layer no way requires information from another layer
d) It is an application specific network model
Answer: c
Explanation: One layer may use the information from another layer, for example timestamp value. The information is contained in the header inserted by the previous layer. The headers are added as the packet moves from higher layers to the lower layers.
30. In the OSI model, as a data packet moves from the lower to the upper layers, headers are _
a) Added
b) Removed
c) Rearranged
d) Randomized
Answer: b
Explanation: In OSI reference model, when data packet moves from lower layers to higher layer, headers get removed. Whereas when the data packet moves from higher layer to lower layers, headers are added. These headers contain the essential control information for the protocols used on the specific layer.
29. In TCP IP Model, when data is sent from device A to device B, the 5th layer to receive data at B is __
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: a
Explanation: In TCP/IP model, the fifth layer is application layer. When data is sent from device A to device B, the 5th layer to receive data at B is application layer. Application layer provides the interface between applications and the network. The user interacts with only this layer.
28. In OSI model, when data is sent from device A to device B, the 5th layer to receive data at B is _
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: d
Explanation: In OSI reference model, the fifth layer is Session layer. Session layer provides the mechanism for opening, closing and managing a session between end-user application processes. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
27. Delimiting and synchronization of data exchange is provided by __
a) Application layer
b) Session layer
c) Transport layer
d) Link layer
Answer: b
Explanation: The session layer provides the mechanism for opening, closing and managing a session between end-user application processes. The session layer 5 is responsible for establishing managing synchronizing and terminating sessions. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
26. The functionalities of the presentation layer include __
a) Data compression
b) Data encryption
c) Data description
d) All of the mentioned
Answer: d
Explanation: Some functions of the presentation layer include character-code translation, data conversion, data encryption and decryption, and data translation. It connects the application layer with the layers below converting the human readable text and media to machine readable format and vice-versa.
25. Transport layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Signal transmission
Answer: a
Explanation: Application, Presentation, Session and Transport layer are implemented in the end system. The transport layer handles the process to process delivery of the packet through ports.
24. Application layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Packet transport
Answer: a
Explanation: Not only application layer, but presentation layer, session layer and transport layer are also implemented in the end system. The layers below are implemented outside the end system, for example, the network layer is implemented on the routers and the physical layer is implemented for the medium.
23. Which of the following layers is an addition to OSI model when compared with TCP IP model?
a) Application layer
b) Presentation layer
c) Session layer
d) Session and Presentation layer
Answer: d
Explanation: The only difference between OSI model and TCP/IP model is that the functions of Presentation and Session layer in the OSI model are handled by the transport layer itself in TCP/IP. OSI is a generalized model and TCP/IP is an application specific model.
22. The number of layers in ISO OSI reference model is __
a) 5
b) 7
c) 6
d) 10
Answer: b
Explanation: The seven layers in ISO OSI reference model is Application, Presentation, Session, Transport, Network, Data link and Physical layer. OSI stands for Open System Interconnect and it is a generalized model.
21. How many layers are present in the Internet protocol stack (TCP/IP model)?
a) 5
b) 7
c) 6
d) 10
Answer: a
Explanation: There are five layers in the Internet Protocol stack. The five layers in Internet Protocol stack is Application, Transport, Network, Data link and Physical layer. The internet protocol stack model is also called the TCP/IP model and it’s used in modern Internet Communication.
20. Which of the following networks extends a private network across public networks?
a) local area network
b) virtual private network
c) enterprise private network
d) storage area network
Answer: b
Explanation: A virtual private network extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.VPN provides enhanced security and online anonymity to users on the internet. It is also used to unblock websites which are unavailable in certain regions.
19. In TCP IP Model, when data is sent from device A to device B, the 5th layer to receive data at B is __
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: a
Explanation: Network congestion occurs when traffic in the network is more than the network could handle. To avoid network congestion, the network management uses various open-loop and closed-loop congestion control techniques.
18. In OSI model, when data is sent from device A to device B, the 5th layer to receive data at B is _
a) Application layer
b) Transport layer
c) Link layer
d) Session layer
Answer: d
Explanation: In OSI reference model, the fifth layer is Session layer. Session layer provides the mechanism for opening, closing and managing a session between end-user application processes. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
17. Delimiting and synchronization of data exchange is provided by __
a) Application layer
b) Session layer
c) Transport layer
d) Link layer
Answer: b
Explanation: The session layer provides the mechanism for opening, closing and managing a session between end-user application processes. The session layer 5 is responsible for establishing managing synchronizing and terminating sessions. In TCP/IP protocol stack, the functions of the session layer are handled by the transport layer itself and thus the session layer is missing from the TCP/IP model.
16. The functionalities of the presentation layer include __
a) Data compression
b) Data encryption
c) Data description
d) All of the mentioned
Answer: d
Explanation: Some functions of the presentation layer include character-code translation, data conversion, data encryption and decryption, and data translation. It connects the application layer with the layers below converting the human readable text and media to machine readable format and vice-versa.
15. Transport layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Signal transmission
Answer: a
Explanation: Application, Presentation, Session and Transport layer are implemented in the end system. The transport layer handles the process to process delivery of the packet through ports.
14. Application layer is implemented in __
a) End system
b) NIC
c) Ethernet
d) Packet transport
Answer: a
Explanation: Not only application layer, but presentation layer, session layer and transport layer are also implemented in the end system. The layers below are implemented outside the end system, for example, the network layer is implemented on the routers and the physical layer is implemented for the medium.
13. Which of the following layers is an addition to OSI model when compared with TCP IP model?
a) Application layer
b) Presentation layer
c) Session layer
d) Session and Presentation layer
Answer: d
Explanation: The only difference between OSI model and TCP/IP model is that the functions of Presentation and Session layer in the OSI model are handled by the transport layer itself in TCP/IP. OSI is a generalized model and TCP/IP is an application specific model.
12. The number of layers in ISO OSI reference model is __
a) 5
b) 7
c) 6
d) 10
Answer: b
Explanation: The seven layers in ISO OSI reference model is Application, Presentation, Session, Transport, Network, Data link and Physical layer. OSI stands for Open System Interconnect and it is a generalized model.
11. How many layers are present in the Internet protocol stack (TCP/IP model)?
a) 5
b) 7
c) 6
d) 10
Answer: a
Explanation: There are five layers in the Internet Protocol stack. The five layers in Internet Protocol stack is Application, Transport, Network, Data link and Physical layer. The internet protocol stack model is also called the TCP/IP model and it’s used in modern Internet Communication.
10. Which of the following networks extends a private network across public networks?
a) local area network
b) virtual private network
c) enterprise private network
d) storage area network
Answer: b
Explanation: A virtual private network extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network.VPN provides enhanced security and online anonymity to users on the internet. It is also used to unblock websites which are unavailable in certain regions.
9. Network congestion occurs _
a) in case of traffic overloading
b) when a system terminates
c) when connection between two nodes terminates
d) in case of transfer failure
Answer: a
Explanation: Network congestion occurs when traffic in the network is more than the network could handle. To avoid network congestion, the network management uses various open-loop and closed-loop congestion control techniques.
8. A list of protocols used by a system, one protocol per layer, is called __
a) protocol architecture
b) protocol stack
c) protocol suite
d) protocol system
Answer: b
Explanation: A protocol stack refers to a group of protocols that are running concurrently that are employed for the implementation of network protocol suite. Each layer in the network model has to use one specific protocol from the protocol stack.
7. A __ is a device that forwards packets between networks by processing the routing information included in the packet.
a) bridge
b) firewall
c) router
d) hub
Answer: c
Explanation: A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. They make use of routing protocols like RIP to find the cheapest path to the destination.
6. Bluetooth is an example of __
a) personal area network
b) local area network
c) virtual private network
d) wide area network
Answer: a
Explanation: Bluetooth is a wireless technology used to create a wireless personal area network for data transfer up to a distance of 10 meters. It operates on 2.45 GHz frequency band for transmission.
5. Communication channel is shared by all the machines on the network in __
a) broadcast network
b) unicast network
c) multicast network
d) anycast network
Answer: a
Explanation: In a broadcast network, information is sent to all stations in a network whereas in a multicast network the data or information is sent to a group of stations in the network. In unicast network, information is sent to only one specific station. The broadcast address of the network is the last assigned address of the network.
4. In computer network nodes are _
a) the computer that originates the data
b) the computer that routes the data
c) the computer that terminates the data
d) all of the mentioned
Answer: d
Explanation: In a computer network, a node can be anything that is capable of sending data or receiving data or even routing the data to its destination. Routers, Computers and Smartphones are some examples of network nodes.
3. Which of the following computer networks is built on the top of another network?
a) prior network
b) chief network
c) prime network
d) overlay network
Answer: d
Explanation: An overlay network is a computer network that is built on top of another network. Some examples of an overlay network are Virtual Private Networks (VPN) and Peer-to-Peer Networks (P2P).
2. Two devices are in network if __
a) a process in one device is able to exchange information with a process in another device
b) a process is running on both devices
c) PIDs of the processes running of different devices are same
d) a process is active and another is inactive
Answer: a
Explanation: A computer network, or data network, is a digital telecommunications network which allows nodes to share resources. In computer networks, computing devices exchange data with each other using connections between nodes. The nodes have certain processes which enable them to share a specific type of data using a distinct protocol.
1. When collection of various computers seems a single coherent system to its client, then it is called _
a) computer network
b) distributed system
c) networking system
d) mail system
Answer: b
Explanation: A Computer network is defined as a collection of interconnected computers which uses a single technology for connection.
A distributed system is also the same as computer network but the main difference is that the whole collection of computers appears to its users as a single coherent system.
Example:- World wide web
105. Scheduling is done so as to __
a) increase the waiting time
b) keep the waiting time the same
c) decrease the waiting time
d) none of the mentioned
Answer: c
Explanation: None.
104. What is Waiting time?
a) the total time in the blocked and waiting queues
b) the total time spent in the ready queue
c) the total time spent in the running queue
d) the total time from the completion till the submission of a process
Answer: b
Explanation: None.
103. Scheduling is done so as to __
a) increase the turnaround time
b) decrease the turnaround time
c) keep the turnaround time same
d) there is no relation between scheduling and turnaround time
Answer: b
Explanation: None.
102. What is Turnaround time?
a) the total waiting time for a process to finish execution
b) the total time spent in the ready queue
c) the total time spent in the running queue
d) the total time from the completion till the submission of a process
Answer: d
Explanation: None.
101. Scheduling is done so as to __
a) increase the throughput
b) decrease the throughput
c) increase the duration of a specific amount of work
d) none of the mentioned
Answer: a
Explanation: None.
100. Scheduling is done so as to __
a) increase CPU utilization
b) decrease CPU utilization
c) keep the CPU more idle
d) none of the mentioned
Answer: a
Explanation: None.
99. What is Dispatch latency?
a) the speed of dispatching a process from running to the ready state
b) the time of dispatching a process from running to ready state and keeping the CPU idle
c) the time to stop one process and start running another one
d) none of the mentioned
Answer: c
Explanation: None.
98. The switching of the CPU from one process or thread to another is called __
a) process switch
b) task switch
c) context switch
d) all of the mentioned
Answer:d
Explanation: None.
97. In the following cases non – preemptive scheduling occurs?
a) When a process switches from the running state to the ready state
b) When a process goes from the running state to the waiting state
c) When a process switches from the waiting state to the ready state
d) All of the mentioned
Answer: b
Explanation: There is no other choice.
96. A process is selected from the _ queue by the _ scheduler, to be executed.
a) blocked, short term
b) wait, long term
c) ready, short term
d) ready, long term
Answer: c
Explanation: None.
95. An I/O bound program will typically have __
a) a few very short CPU bursts
b) many very short I/O bursts
c) many very short CPU bursts
d) a few very short I/O bursts
Answer: c
Explanation: None.
94. What are the two steps of a process execution?
a) I/O & OS Burst
b) CPU & I/O Burst
c) Memory & I/O Burst
d) OS & Memory Burst
Answer: b
Explanation: None.
93. With multiprogramming __ is used productively.
a) time
b) space
c) money
d) all of the mentioned
Answer: a
Explanation: None.
92. CPU scheduling is the basis of _
a) multiprocessor systems
b) multiprogramming operating systems
c) larger memory sized systems
d) none of the mentioned
Answer: b
Explanation: None.
92. In multilevel feedback scheduling algorithm __
a) a process can move to a different classified ready queue
b) classification of ready queue is permanent
c) processes are not classified into groups
d) none of the mentioned
Answer: a
Explanation: None.
91. Process are classified into different groups in __
a) shortest job scheduling algorithm
b) round robin scheduling algorithm
c) priority scheduling algorithm
d) multilevel queue scheduling algorithm
Answer: d
Explanation: None.
90. Which algorithm is defined in Time quantum?
a) shortest job scheduling algorithm
b) round robin scheduling algorithm
c) priority scheduling algorithm
d) multilevel queue scheduling algorithm
Answer: b
Explanation: None.
89. In priority scheduling algorithm, when a process arrives at the ready queue, its priority is compared with the priority of __
a) all process
b) currently running process
c) parent process
d) init process
Answer: b
Explanation: None.
89. In priority scheduling algorithm __
a) CPU is allocated to the process with highest priority
b) CPU is allocated to the process with lowest priority
c) Equal priority processes can not be scheduled
d) None of the mentioned
Answer: a
Explanation: None.
88. Which scheduling algorithm allocates the CPU first to the process that requests the CPU first?
a) first-come, first-served scheduling
b) shortest job scheduling
c) priority scheduling
d) none of the mentioned
Answer: a
Explanation: None.
87. The interval from the time of submission of a process to the time of completion is termed as __
a) waiting time
b) turnaround time
c) response time
d) throughput
Answer: b
Explanation: None.
86. The processes that are residing in main memory and are ready and waiting to execute are kept on a list called _
a) job queue
b) ready queue
c) execution queue
d) process queue
Answer: b
Explanation: None.
85. Which operation is performed by an interrupt handler?Which module gives control of the CPU to the process selected by the short-term scheduler?
a) dispatcher
b) interrupt
c) scheduler
d) none of the mentioned
Answer: a
Explanation: None.
84. How does the Hardware trigger an interrupt?
a) Sending signals to CPU through a system bus
b) Executing a special program called interrupt program
c) Executing a special program called system program
d) Executing a special operation called system call
Answer: a
Explanation: None.
83. In the layered approach of Operating Systems __
a) Bottom Layer(0) is the User interface
b) Highest Layer(N) is the User interface
c) Bottom Layer(N) is the hardware
d) Highest Layer(N) is the hardware
Answer: b
Explanation: None.
82. In an interrupt driven input/output __
a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready
b) the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c) the CPU receives an interrupt when the device is ready for the next byte
d) the CPU runs a user written code and does accordingly
Answer: c
Explanation: None.
81. In a programmed input/output(PIO) __
a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready
b) the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c) the CPU receives an interrupt when the device is ready for the next byte
d) the CPU runs a user written code and does accordingly
Answer: a
Explanation: None.
80. In a memory mapped input/output __
a) the CPU uses polling to watch the control bit constantly, looping to see if a device is ready
b) the CPU writes one data byte to the data register and sets a bit in control register to show that a byte is available
c) the CPU receives an interrupt when the device is ready for the next byte
d) the CPU runs a user written code and does accordingly
Answer: b
Explanation: None.
79. DMA is used for __
a) High speed devices(disks and communications network)
b) Low speed devices
c) Utilizing CPU cycles
d) All of the mentioned
Answer: a
Explanation: None.
78. What is an interrupt vector?
a) It is an address that is indexed to an interrupt handler
b) It is a unique device number that is indexed by an address
c) It is a unique identity given to an interrupt
d) None of the mentioned
Answer: a
Explanation: None.
77. What is an ISR?
a) Information Service Request
b) Interrupt Service Request
c) Interrupt Service Routine
d) Information Service Routine
Answer: c
Explanation: None.
76. What is a trap/exception?
a) hardware generated interrupt caused by an error
b) software generated interrupt caused by an error
c) user generated interrupt caused by an error
d) none of the mentioned
Answer: b
Explanation: None.
76. How does the software trigger an interrupt?
a) Sending signals to CPU through bus
b) Executing a special operation called system call
c) Executing a special program called system program
d) Executing a special program called interrupt trigger program
Answer: b
Explanation: None.
75. The initial program that is run when the computer is powered up is called __
a) boot program
b) bootloader
c) initializer
d) bootstrap program
Answer: d
Explanation: None.
74. The remote method invocation __
a) allows a process to invoke memory on a remote object
b) allows a thread to invoke a method on a remote object
c) allows a thread to invoke memory on a remote object
d) allows a process to invoke a method on a remote object
Answer: b
Explanation: None.
73. What is the full form of RMI?
a) Remote Memory Installation
b) Remote Memory Invocation
c) Remote Method Installation
d) Remote Method Invocation
Answer: d
Explanation: None.
72 .To resolve the problem of data representation on different systems RPCs define _
a) machine dependent representation of data
b) machine representation of data
c) machine-independent representation of data
d) none of the mentioned
Answer: c
Explanation: None.
71. What is stub?
a) transmits the message to the server where the server side stub receives the message and invokes procedure on the server side
b) packs the parameters into a form transmittable over the network
c) locates the port on the server
d) all of the mentioned
Answer: d
Explanation: None.
70. RPC provides a(an) _ on the client-side, a separate one for each remote procedure.
a) stub
b) identifier
c) name
d) process identifier
Answer: a
Explanation: None.
69. To differentiate the many network services a system supports __ are used.
a) Variables
b) Sockets
c) Ports
d) Service names
Answer: c
Explanation: None.
68. Remote Procedure Calls are used __
a) for communication between two processes remotely different from each other on the same system
b) for communication between two processes on the same system
c) for communication between two processes on separate systems
d) none of the mentioned
Answer: c
Explanation: None.
67. The Zero Capacity queue __
a) is referred to as a message system with buffering
b) is referred to as a message system with no buffering
c) is referred to as a link
d) none of the mentioned
Answer: b
Explanation: The Zero capacity queue is referred to as a message system with no buffering. Zero capacity queue has maximum capacity of Zero; thus message queue does not have any waiting message in it.
66. In the Zero capacity queue __
a) the queue can store at least one message
b) the sender blocks until the receiver receives the message
c) the sender keeps sending and the messages don’t wait in the queue
d) none of the mentioned
Answer: b
Explanation: In the Zero capacity queue the sender blocks until the receiver receives the message. Zero capacity queue has maximum capacity of Zero; thus message queue does not have any waiting message in it.
65. In the non blocking send __
a) the sending process keeps sending until the message is received
b) the sending process sends the message and resumes operation
c) the sending process keeps sending until it receives a message
d) none of the mentioned
Answer: b
Explanation: In the non blocking send, the sending process sends the message and resumes operation. Sending process doesn’t care about reception. It is also known as asynchronous send.
64.In indirect communication between processes P and Q __
a) there is another process R to handle and pass on the messages between P and Q
b) there is another machine between the two processes to help communication
c) there is a mailbox to help communication between P and Q
d) none of the mentioned
Answer: c
Explanation: In indirect communication between processes P and Q there is a mailbox to help communication between P and Q. A mailbox can be viewed abstractly as an object into which messages can be placed by processes and from which messages can be removed.
63. Which of the following are TRUE for direct communication?
a) A communication link can be associated with N number of process(N = max. number of processes supported by system)
b) A communication link is associated with exactly two processes
c) Exactly N/2 links exist between each pair of processes(N = max. number of processes supported by system)
d) Exactly two link exists between each pair of processes
Answer: b
Explanation: For direct communication, a communication link is associated with exactly two processes. One communication link must exist between a pair of processes.
62. The link between two processes P and Q to send and receive messages is called __
a) communication link
b) message-passing link
c) synchronization link
d) all of the mentioned
Answer: a
Explanation: The link between two processes P and Q to send and receive messages is called communication link. Two processes P and Q want to communicate with each other; there should be a communication link that must exist between these two processes so that both processes can able to send and receive messages using that link.
61. Messages sent by a process __
a) have to be of a fixed size
b) have to be a variable size
c) can be fixed or variable sized
d) none of the mentioned
Answer: c
Explanation: Messages sent by a process can be fixed or variable size. If the message size of the process is fixed then system level implementation is straightforward but it makes the task of programming more difficult. If the message size of the process is variable then system level implementation is more complex but it makes the task of programming simpler.
60. Which of the following two operations are provided by the IPC facility?
a) write & delete message
b) delete & receive message
c) send & delete message
d) receive & send message
Answer: d
Explanation: Two operations provided by the IPC facility are receive and send messages. Exchange of data takes place in cooperating processes.
59. Message passing system allows processes to __
a) communicate with each other without sharing the same address space
b) communicate with one another by resorting to shared data
c) share data
d) name the recipient or sender of the message
Answer: a
Explanation: Message Passing system allows processes to communicate with each other without sharing the same address space.
58. What is Interprocess communication?
a) allows processes to communicate and synchronize their actions when using the same address space
b) allows processes to communicate and synchronize their actions
c) allows the processes to only synchronize their actions without communication
d) none of the mentioned
Answer: b
Explanation: Interprocess Communication allows processes to communicate and synchronize their actions. Interprocess Communication (IPC) mechanism is used by cooperating processes to exchange data and information.
57. The child process can __
a) be a duplicate of the parent process
b) never be a duplicate of the parent process
c) cannot have another program loaded into it
d) never have another program loaded into it
Answer: a
Explanation: The child process can be a duplicate of the parent process. The child process created by fork consists of a copy of the address space of the parent process.
56. In UNIX, the return value for the fork system call is _ for the child process and _ for the parent process.
a) A Negative integer, Zero
b) Zero, A Negative integer
c) Zero, A nonzero integer
d) A nonzero integer, Zero
Answer: c
Explanation: In Unix, the return value of the fork system call is Zero for the child process and Non-zero value for parent process. A fork system call returns the PID of a newly created (child) process to the parent and returns Zero to that newly created (child) process.
55. In UNIX, each process is identified by its __
a) Process Control Block
b) Device Queue
c) Process Identifier
d) None of the mentioned
Answer: c
Explanation: In Unix, each process is identified by its Process Identifier or PID. The PID provides unique value to each process in the system so that each process can be identified uniquely.
54. With _ only one process can execute at a time; meanwhile all other process are waiting for the processor. With __ more than one process can be running simultaneously each on a different processor.
a) Multiprocessing, Multi programming
b) Multi programming, Uni processing
c) Multi programming, Multi processing
d) Uni programming, Multi processing
Answer: d
Explanation: With Uniprogramming only one process can execute at a time; meanwhile all other processes are waiting for the processor. With Multiprocessing more than one process can run simultaneously each on different processors. The Uniprogramming system has only one program inside the core while the Multiprocessing system has multiple processes inside multiple cores. The core is one which executes instructions and stores data locally into registers.
53. Cascading termination refers to termination of all child processes if the parent process terminates __
a) Normally
b) Abnormally
c) Normally or abnormally
d) None of the mentioned
Answer: c
Explanation: Cascading termination refers to termination of all child processes if the parent process terminates Normally or Abnormally. Some systems don’t allow child processes to exist if the parent process has terminated. Cascading termination is normally initiated by the operating system.
52. A parent process calling _ system call will be suspended until children processes terminate.
a) wait
b) fork
c) exit
d) exec
Answer: a
Explanation: A parent process calling wait system call will be suspended until children processes terminate. A parameter is passed to wait system call which will obtain exit status of child as well as wait system call returns PID of terminated process.
51. Restricting the child process to a subset of the parent’s resources prevents any process from __
a) overloading the system by using a lot of secondary storage
b) under-loading the system by very less CPU utilization
c) overloading the system by creating a lot of sub-processes
d) crashing the system by utilizing multiple resources
Answer: c
Explanation: Restricting the child process to a subset of the parent’s resources prevents any process from overloading the system by creating a lot of sub-processes. A process creates a child process, child process requires certain resources to complete its task. A child process can demand required resources directly from the system, but by doing this system will be overloaded. So to avoid overloading of the system, the parent process shares its resources among children.
50. A monitor is a module that encapsulates __
a) shared data structures
b) procedures that operate on shared data structure
c) synchronization between concurrent procedure invocation
d) all of the mentioned
Answer: d
Explanation: A monitor is a module that encapsulates shared data structures, procedures that operate on shared data structure, synchronization between concurrent procedure invocation.
49. Process synchronization can be done on __
a) hardware level
b) software level
c) both hardware and software level
d) none of the mentioned
Answer: c
Explanation: Process synchronization can be done on both hardware and software level. Critical section problems can be resolved using hardware synchronization. But this method is not simple for implementation so software synchronization is mostly used.
48. When high priority task is indirectly preempted by medium priority task effectively inverting the relative priority of the two tasks, the scenario is called __
a) priority inversion
b) priority removal
c) priority exchange
d) priority modification
Answer: a
Explanation: When a high priority task is indirectly preempted by a medium priority task effectively inverting the relative priority of the two tasks, the scenario is called priority inversion.
47. Mutual exclusion can be provided by the __
a) mutex locks
b) binary semaphores
c) both mutex locks and binary semaphores
d) none of the mentioned
Answer: c
Explanation: Mutual exclusion can be provided by both mutex locks and binary semaphore. Mutex is a short form of Mutual Exclusion. Binary semaphore also provides a mechanism for mutual exclusion. Binary semaphore behaves similar to mutex locks.
46. A semaphore is a shared integer variable __
a) that can not drop below zero
b) that can not be more than zero
c) that can not drop below one
d) that can not be more than one
Answer: a
Explanation: A semaphore is a shared integer variable that can not drop below zero. In binary semaphore, if the value of the semaphore variable is zero that means there is a process that uses a critical resource and no other process can access the same critical resource until it is released. In Counting semaphore, if the value of the semaphore variable is zero that means there is no resource available.
45. Which one of the following is a synchronization tool?
a) thread
b) pipe
c) semaphore
d) socket
Answer: c
Explanation: Semaphore is a synchronization tool. Semaphore is a mechanism which synchronizes or controls access of threads on critical resources. There are two types of semaphores i) Binary Semaphore ii) Counting Semaphore.
44. If a process is executing in its critical section, then no other processes can be executing in their critical section. What is this condition called?
a) mutual exclusion
b) critical exclusion
c) synchronous exclusion
d) asynchronous exclusion
Answer: a
Explanation: If a process is executing in its critical section, then no other processes can be executed in their critical section. This condition is called Mutual Exclusion. Critical section of the process is shared between multiple processes. If this section is executed by more than one or all of them concurrently then the outcome of this is not as per desired outcome. For this reason the critical section of the process should not be executed concurrently.
43. When several processes access the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place is called __
a) dynamic condition
b) race condition
c) essential condition
d) critical condition
Answer: b
Explanation: When several processes access the same data concurrently and the outcome of the execution depends on the particular order in which access takes place is called race condition.
42. Which process can be affected by other processes executing in the system?
a) cooperating process
b) child process
c) parent process
d) init process
Answer: a
Explanation: A cooperating process can be affected by other processes executing in the system. Also it can affect other processes executing in the system. A process shares data with other processes, such a process is known as a cooperating process.
Which of the following need not necessarily be saved on a context switch between processes?
a) General purpose registers
b) Translation lookaside buffer
c) Program counter
d) All of the mentioned
Answer: b
Explanation: Translation Look-aside Buffer (TLB) need not necessarily be saved on a context switch between processes. A special, small, fast-lookup hardware cache is called Translation Look-aside Buffer. TLB used to reduce memory access time.
40. The context of a process in the PCB of a process does not contain __
a) the value of the CPU registers
b) the process state
c) memory-management information
d) context switch time
Answer: d
Explanation: The context of a process in the PCB of a process does not contain context switch time. When switching CPU from one process to another, the current context of the process needs to be saved. It includes values of the CPU registers, process states, memory-management information.
39. Suppose that a process is in “Blocked” state waiting for some I/O service. When the service is completed, it goes to the __
a) Running state
b) Ready state
c) Suspended state
d) Terminated state
Answer: b
Explanation: Suppose that a process is in “Blocked” state waiting for some I/O service. When the service is completed, it goes to the ready state. Process never goes directly to the running state from the waiting state. Only processes which are in ready state go to the running state whenever CPU allocated by operating system.
38. In a multiprogramming environment __
a) the processor executes more than one process at a time
b) the programs are developed by more than one person
c) more than one process resides in the memory
d) a single user can execute many programs at the same time
Answer: c
Explanation: In a multiprogramming environment more than one process resides in the memory. Whenever a CPU is available, one process amongst all present in memory gets the CPU for execution. Multiprogramming increases CPU utilization.
37. In a time-sharing operating system, when the time slot given to a process is completed, the process goes from the running state to the __
a) Blocked state
b) Ready state
c) Suspended state
d) Terminated state
Answer: b
Explanation: In a time-sharing operating system, when the time slot given to a process is completed, the process goes from the running state to the Ready State. In a time-sharing operating system unit time is defined for sharing CPU, it is called a time quantum or time slice. If a process takes less than 1 time quantum, then the process itself releases the CPU.
36. The only state transition that is initiated by the user process itself is __
a) block
b) wakeup
c) dispatch
d) none of the mentioned
Answer: a
Explanation: The only state transition that is initiated by the user process itself is block. Whenever a user process initiates an I/O request it goes into block state unless and until the I/O request is not completed.
35 . The primary distinction between the short term scheduler and the long term scheduler is __
a) The length of their queues
b) The type of processes they schedule
c) The frequency of their execution
d) None of the mentioned
Answer: c
Explanation: The primary distinction between the short-term scheduler and the long-term scheduler is the frequency of their execution. The short-term scheduler executes frequently while the long-term scheduler executes much less frequently.
34. What is a short-term scheduler?
a) It selects which process has to be brought into the ready queue
b) It selects which process has to be executed next and allocates CPU
c) It selects which process to remove from memory by swapping
d) None of the mentioned
Answer: b
Explanation: A short-term scheduler selects a process which has to be executed next and allocates CPU. Short-term scheduler selects a process from the ready queue. It selects processes frequently.
33. What is a medium-term scheduler?
a) It selects which process has to be brought into the ready queue
b) It selects which process has to be executed next and allocates CPU
c) It selects which process to remove from memory by swapping
d) None of the mentioned
Answer: c
Explanation: A medium-term scheduler selects which process to remove from memory by swapping. The medium-term scheduler swapped out the process and later swapped in. Swapping helps to free up memory.
32. If all processes I/O bound, the ready queue will almost always be _ and the Short term Scheduler will have a _ to do.
a) full, little
b) full, lot
c) empty, little
d) empty, lot
Answer: c
Explanation: If all processes are I/O bound, the ready queue will almost empty and the short-term scheduler will have a little to do. I/O bound processes spend more time doing I/O than computation.
31. What is a long-term scheduler?
a) It selects processes which have to be brought into the ready queue
b) It selects processes which have to be executed next and allocates CPU
c) It selects processes which heave to remove from memory by swapping
d) None of the mentioned
Answer: a
Explanation: A long-term scheduler selects processes which have to be brought into the ready queue. When processes enter the system, they are put in the job queue. Long-term scheduler selects processes from the job queue and puts them in the ready queue. It is also known as Job Scheduler.
30. What will happen when a process terminates?
a) It is removed from all queues
b) It is removed from all, but the job queue
c) Its process control block is de-allocated
d) Its process control block is never de-allocated
Answer: a
Explanation: When a process terminates, it removes from all queues. All allocated resources to that particular process are deallocated and all those resources are returned back to OS.
29. When the process issues an I/O request __
a) It is placed in an I/O queue
b) It is placed in a waiting queue
c) It is placed in the ready queue
d) It is placed in the Job queue
Answer: a
Explanation: When the process issues an I/O request it is placed in an I/O queue. I/O is a resource and it should be used effectively and every process should get access to it. There might be multiple processes which requested for I/O. Depending on scheduling algorithm I/O is allocated to any particular process and after completing I/O operation, I/O access is returned to the OS.
28. Which of the following do not belong to queues for processes?
a) Job Queue
b) PCB queue
c) Device Queue
d) Ready Queue
Answer: b
Explanation: PCB queue does not belong to queues for processes. PCB is a process control block which contains information related to process. Each process is represented by PCB.
27. A single thread of control allows the process to perform __
a) only one task at a time
b) multiple tasks at a time
c) only two tasks at a time
d) all of the mentioned
Answer: a
Explanation: A single thread of control allows the process to perform only one task at a time. In the case of multi-core, multiple threads can be run simultaneously and can perform multiple tasks at a time.
26. What is the degree of multiprogramming?
a) the number of processes executed per unit time
b) the number of processes in the ready queue
c) the number of processes in the I/O queue
d) the number of processes in memory
Answer: d
Explanation: Multiprogramming means the number of processes are in the ready states. To increase utilization of CPU, Multiprogramming is one of the most important abilities of OS. Generally, a single process cannot use CPU or I/O at all time, whenever CPU or I/O is available another process can use it. By doing this CPU utilization is increased.
25. The entry of all the PCBs of the current processes is in __
a) Process Register
b) Program Counter
c) Process Table
d) Process Unit
Answer: c
Explanation: The entry of all the PCBs of the current processes is in Process Table. The Process Table has the status of each and every process that is created in OS along with their PIDs.
24. What is a Process Control Block?
a) Process type variable
b) Data Structure
c) A secondary storage section
d) A Block in memory
Answer: b
Explanation: A Process Control Block (PCB) is a data structure. It contains information related to a process such as Process State, Program Counter, CPU Register, etc. Process Control Block is also known as Task Control Block.
23. Which of the following is not the state of a process?
a) New
b) Old
c) Waiting
d) Running
Answer: b
Explanation: There is no process state such as old. When a process is created then the process is in New state. When the process gets the CPU for its execution then the process is in Running state. When the process is waiting for an external event then the process is in a Waiting state.
22. The state of a process is defined by __
a) the final activity of the process
b) the activity just executed by the process
c) the activity to next be executed by the process
d) the current activity of the process
Answer: d
Explanation: The state of a process is defined by the current activity of the process. A process state changes when the process executes. The process states are as New, Ready, Running, Wait, Terminated.
21. The number of processes completed per unit time is known as __
a) Output
b) Throughput
c) Efficiency
d) Capacity
Answer: b
Explanation: The number of processes completed per unit time is known as Throughput. Suppose there are 4 processes A, B, C & D they are taking 1, 3, 4 & 7 units of time respectively for their executions. For 10 units of time, throughput is high if process A, B & C are running first as 3 processes can execute. If process C runs first then throughput is low as maximum only 2 processes can execute. Throughput is low for processes which take a long time for execution. Throughput is high for processes which take a short time for execution.
20. A Process Control Block(PCB) does not contain which of the following?
a) Code
b) Stack
c) Bootstrap program
d) Data
Answer: c
Explanation: Process Control Block (PCB) contains information related to a process such as Process State, Program Counter, CPU Register, etc. Process Control Block is also known as Task Control Block. Bootstrap program is a program which runs initially when the system or computer is booted or rebooted.
19. Which system call can be used by a parent process to determine the termination of child process?
a) wait
b) exit
c) fork
d) get
Answer: a
Explanation: wait() system call is used by the parent process to determine termination of child process. The parent process uses wait() system call and gets the exit status of the child process as well as the pid of the child process which is terminated.
18. A process stack does not contain __
a) Function parameters
b) Local variables
c) Return addresses
d) PID of child process
Answer: d
Explanation: Process stack contains Function parameters, Local variables and Return address. It does not contain the PID of child process.
17. A set of processes is deadlock if __
a) each process is blocked and will remain so forever
b) each process is terminated
c) all processes are trying to kill each other
d) none of the mentioned
Answer: a
Explanation: Deadlock is a situation which occurs because process A is waiting for one resource and holds another resource (blocking resource). At the same time another process B demands blocking a resource as it is already held by a process A, process B is waiting state unless and until process A releases occupied resource.
16. What is interprocess communication?
a) communication within the process
b) communication between two process
c) communication between two threads of same process
d) none of the mentioned
Answer: b
Explanation: Interprocess Communication (IPC) is a communication mechanism that allows processes to communicate with each other and synchronise their actions without using the same address space. IPC can be achieved using shared memory and message passing.
15. What is the ready state of a process?
a) when process is scheduled to run after some execution
b) when process is unable to run until some task has been completed
c) when process is using the CPU
d) none of the mentioned
Answer: a
Explanation: Ready state of the process means process has all necessary resources which are required for execution of that process when CPU is allocated. Process is ready for execution but waiting for the CPU to be allocated.
14. A process can be terminated due to __
a) normal exit
b) fatal error
c) killed by another process
d) all of the mentioned
Answer: d
Explanation: A process can be terminated normally by completing its task or because of fatal error or killed by another process or forcefully killed by a user. When the process completes its task without any error then it exits normally. The process may exit abnormally because of the occurrence of fatal error while it is running. The process can be killed or terminated forcefully by another process.
13. In Unix, Which system call creates the new process?
a) fork
b) create
c) new
d) none of the mentioned
Answer: a
Explanation: In UNIX, a new process is created by fork() system call. fork() system call returns a process ID which is generally the process id of the child process created.
12. In operating system, each process has its own __
a) address space and global variables
b) open files
c) pending alarms, signals and signal handlers
d) all of the mentioned
Answer: d
Explanation: In Operating Systems, each process has its own address space which contains code, data, stack and heap segments or sections. Each process also has a list of files which is opened by the process as well as all pending alarms, signals and various signal handlers.
11. The systems which allow only one process execution at a time, are called __
a) uniprogramming systems
b) uniprocessing systems
c) unitasking systems
d) none of the mentioned
Answer: b
Explanation: Those systems which allow more than one process execution at a time, are called multiprocessing systems. Uniprocessing means only one processor.
10. The OS X has __
a) monolithic kernel
b) hybrid kernel
c) microkernel
d) monolithic kernel with modules
Answer: d
Explanation: OS X has a hybrid kernel. Hybrid kernel is a combination of two different kernels. OS X is developed by Apple and originally it is known as Mac OS X.
9. Which one of the following is not a real time operating system?
a) VxWorks
b) QNX
c) RTLinux
d) Palm OS
Answer: d
Explanation: VxWorks, QNX & RTLinux are real-time operating systems. Palm OS is a mobile operating system. Palm OS is developed for Personal Digital Assistants (PDAs).
8. Which facility dynamically adds probes to a running system, both in user processes and in the kernel?
a) DTrace
b) DLocate
c) DMap
d) DAdd
Answer: a
Explanation: A facility that dynamically adds probes to a running system, both in user process and in the kernel is called DTrace. This is very much useful in troubleshooting kernels in real-time.
7. If a process fails, most operating system write the error information to a __
a) log file
b) another running process
c) new file
d) none of the mentioned
Answer: a
Explanation: If a process fails, most operating systems write the error information to a log file. Log file is examined by the debugger, to find out what is the actual cause of that particular problem. Log file is useful for system programmers for correcting errors.
6. In Operating Systems, which of the following is/are CPU scheduling algorithms?
a) Round Robin
b) Shortest Job First
c) Priority
d) All of the mentioned
Answer: d
Explanation: In Operating Systems, CPU scheduling algorithms are:
i) First Come First Served scheduling
ii) Shortest Job First scheduling
iii) Priority scheduling
iv) Round Robin scheduling
v) Multilevel Queue scheduling
vi) Multilevel Feedback Queue scheduling
All of these scheduling algorithms have their own advantages and disadvantages.
5. What is the main function of the command interpreter?
a) to get and execute the next user-specified command
b) to provide the interface between the API and application program
c) to handle the files in operating system
d) none of the mentioned
Answer: a
Explanation: The main function of command interpreter is to get and execute the next user-specified command. Command Interpreter checks for valid command and then runs that command else it will throw an error.
4. Which one of the following error will be handle by the operating system?
a) power failure
b) lack of paper in printer
c) connection failure in the network
d) all of the mentioned
Answer: d
Explanation: All the mentioned errors are handled by OS. The OS is continuously monitoring all of its resources. Also, the OS is constantly detecting and correcting errors.
3. Which one of the following is not true?
a) kernel is the program that constitutes the central core of the operating system
b) kernel is the first part of operating system to load into memory during booting
c) kernel is made of various modules which can not be loaded in running operating system
d) kernel remains in the memory during the entire computer session
Answer: c
Explanation: Kernel is the first program which is loaded in memory when OS is loading as well as it remains in memory till OS is running. Kernel is the core part of the OS which is responsible for managing resources, allowing multiple processes to use the resources and provide services to various processes. Kernel modules can be loaded and unloaded in run-time i.e. in running OS.
2. To access the services of operating system, the interface is provided by the _
a) System calls
b) API
c) Library
d) Assembly instructions
Answer: a
Explanation: To access services of the Operating System an interface is provided by the System Calls. Generally, these are functions written in C and C++. Open, Close, Read, Write are some of most prominently used system calls.
1. What is an operating system?
a) collection of programs that manages hardware resources
b) system service provider to the application programs
c) interface between the hardware and application programs
d) all of the mentioned
Answer: d
Explanation: An Operating System acts as an intermediary between user/user applications/application programs and hardware. It is a program that manages hardware resources. It provides services to application programs.
