PPSC Lecturer of Computer Science Past Paper Questions

1. The network layer concerns with

a) bits

b) frames

c) packets

d) none of the mentioned

Answer:c

2. Which one of the following is not a function of network layer?

a) routing

b) inter-networking

c) congestion control

d) none of the mentioned

Answer:d

3. The 4 byte IP address consists of

a) network address

b) host address

c) both (a) and (b)

d) none of the mentioned

Answer:c

4. In virtual circuit network each packet contains

a) full source and destination address

b) a short VC number

c) both (a) and (b)

d) none of the mentioned

Answer:b

5. Which one of the following routing algorithm can be used for network layer design?

a) shortest path algorithm

b) distance vector routing

c) link state routing

d) all of the mentioned

Answer:d



6. 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) none of the mentioned

Answer:a

7. 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

8. Communication channel is shared by all the machines on the network in

a) broadcast network

b) unicast network

c) multicast network

d) none of the mentioned

Answer:a



9. Bluetooth is an example of

a) personal area network

b) local area network

c) virtual private network

d) none of the mentioned

Answer:a



10. 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) all of the mentioned

Answer:c



11. A list of protocols used by a system, one protocol per layer, is called

a) protocol architecture

b) protocol stack

c) protocol suit

d) none of the mentioned

Answer:b



12. Network congestion occurs

a) in case of traffic overloading

b) when a system terminates

c) when connection between two nodes terminates

d) none of the mentioned

Answer:a



13. Which one of the following 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



14. 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



15. 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



16. 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



17. 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



18. 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



19. 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



20. Time quantum is defined in

a) shortest job scheduling algorithm

b) round robin scheduling algorithm

c) priority scheduling algorithm

d) multilevel queue scheduling algorithm

Answer:b



21. 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



22. 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



23. Which one of the following can not be scheduled by the kernel?

a) kernel level thread

b) user level thread

c) process

d) none of the mentioned

Answer:b

Explanation:User level threads are managed by thread library and the kernel in unaware of them.



24) A process refers to 5 pages, A, B, C, D, E in the order : A, B, C, D, A, B, E, A, B, C, D, E. If the page replacement algorithm is FIFO, the number of page transfers with an empty internal store of 3 frames is :

a) 8

b) 10

c) 9

d) 7

Answer: c

Explanation: None.



25) A memory page containing a heavily used variable that was initialized very early and is in constant use is removed, then the page replacement algorithm used is :

a) LRU

b) LFU

c) FIFO

d) None of these

Answer: c

Explanation: None.

26) Users _______ that their processes are running on a paged system.

a) are aware

b) are unaware

c) None of these

Answer: b

Explanation: None.



27) The aim of creating page replacement algorithms is to :

a) replace pages faster

b) increase the page fault rate

c) decrease the page fault rate

d) to allocate multiple pages to processes

Answer: c

Explanation: None.



28) A FIFO replacement algorithm associates with each page the _______

a) time it was brought into memory

b) size of the page in memory

c) page after and before it

d) All of these

Answer: a

Explanation: None.



29) Optimal page – replacement algorithm is :

a) Replace the page that has not been used for a long time

b) Replace the page that has been used for a long time

c) Replace the page that will not be used for a long time

d) None of these

Answer: c

Explanation: None.



30) Optimal page – replacement algorithm is difficult to implement, because :

a) it requires a lot of information

b) it requires future knowledge of the reference string

c) it is too complex

d) it is extremely expensive

Answer: b

Explanation: None.



31) LRU page – replacement algorithm associates with each page the ______

a) time it was brought into memory

b) the time of that page’s last use

c) page after and before it

d) All of these

Answer: b

Explanation: None.



32) For 3 page frames, the following is the reference string :

7 0 1 2 0 3 0 4 2 3 0 3 2 1 2 0 1 7 0 1

i) How many page faults does the LRU page replacement algorithm produce ?

a) 10

b) 15

c) 11

d) 12

Answer: d

Explanation: None.



33. Build & Fix Model is suitable for programming exercises of ___________ LOC (Line of Code).

a) 100-200

b) 200-400

c) 400-1000

d) above 1000

Answer:a

Explanation: Build & Fix Model is suitable for small projects & programming exercises of 100 or 200 lines.



34. RAD stands for

a) Relative Application Development

b) Rapid Application Development

c) Rapid Application Document

Answer:b

Explanation: None.



35. Which one of the following models is not suitable for accommodating any change?

a) Build & Fix Model

b) Prototyping Model

c) RAD Model

d) Waterfall Model

Answer:d

Explanation: Real projects rarely follow the sequential flow that the Waterfall Model proposes.



36. Which one of the following is not a phase of Prototyping Model?

a) Quick Design

b) Coding

c) Prototype Refinement

d) Engineer Product

Answer:b

Explanation: A prototyping model generates only a working model of a system.



37. RAD Model has

a) 2 phases

b) 3 phase

c) 5 phases

d) 6 phases

Answer:c

Explanation: RAD Model consists of five phases namely:Business modeling,Data modeling,Process modeling,Application generation and Testing & Turnover.



38. What is the major drawback of using RAD Model?

a) Highly specialized & skilled developers/designers are required.

b) Increases re-usability of components.

c) Encourages customer/client feedback.

d) Both a & c.

Answer:d

Explanation: The client may create an unrealistic product vision leading a team to over or under-develop functionality.Also, the specialized & skilled developers are not easily available.



39. SDLC stands for

a) Software Development Life Cycle

b) System Development Life cycle

c) Software Design Life Cycle

d) System Design Life Cycle

Answer:a

Explanation: None.



40. Which model can be selected if user is involved in all the phases of SDLC?

a) Waterfall Model

b) Prototyping Model

c) RAD Model

d) both b & c

Answer:c

Explanation: None.

This set of Database Questions & Answers focuses on “Relational Database and Database Schema”



41. A relational database consists of a collection of

a) Tables

b) Fields

c) Records

d) Keys

Answer:a

Explanation:Fields are the column of the relation or tables.Records are each row in relation.Keys are the constraints in a relation .



42. A ________ in a table represents a relationship among a set of values.

a) Column

b) Key

c) Row

d) Entry

Answer:c

Explanation:Column has only one set of values.Keys are constraints and row is one whole set of attributes.Entry is just a piece of data.



43. The term _______ is used to refer to a row.

a) Attribute

b) Tuple

c) Field

d) Instance

Answer:b

Explanation:Tuple is one entry of the relation with several attributes which are fields.



44. The term attribute refers to a ___________ of a table.

a) Record

b) Column

c) Tuple

d) Key

Answer:b

Explanation:Attribute is a specific domain in the relation which has entries of all tuples.



45. For each attribute of a relation, there is a set of permitted values, called the ________ of that attribute.

a) Domain

b) Relation

c) Set

d) Schema

Answer:a

Explanation:The values of the attribute should be present in the domain.Domain is a set of values permitted .



46. Which forms has a relation that possesses data about an individual entity:

a) 2NF

b) 3NF

c) 4NF

d) 5NF

Answer:c

Explanation: A Table is in 4NF if and only if, for every one of its non-trivial multivalued dependencies X \twoheadrightarrow Y, X is a superkey—that is, X is either a candidate key or a superset thereof.



47. Which forms are based on the concept of functional dependency:

a) 1NF

b) 2NF

c) 3NF

d) 4NF

Answer:c

Explanation: The table is in 3NF if every non-prime attribute of R is non-transitively dependent (i.e. directly dependent) on every superkey of R.



48. _____________ can help us detect poor E-R design.

a) Database Design Process

b) E-R Design Process

c) Relational scheme

d) Functional dependencies

Answer:d

Explanation:For eg.,Suppose an instructor entity set had attributes dept name and dept address, and there is a functional dependency dept name -> dept address.



49. Which of the following has each related entity set has its own schema and there is an additional schema for the relationship set.

a) A many-to-many relationship set

b) A multivalued attribute of an entity set

c) A one-to-many relationship set

d) Both a and b

Answer:a

Explanation:If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from this source.



50. In which of the following , a separate schema is created consisting of that attribute and the primary key of the entity set.

a) A many-to-many relationship set

b) A multivalued attribute of an entity set

c) A one-to-many relationship set

d) Both a and b

Answer:b

Explanation:If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from this source.



51. What is the best way to represent the attributes in a large database?

a) Relational-and

b) Concatenation

c) Dot representation

d) All of the above

Answer:b

Explanation: Example inst sec and student sec.



52. Designers use which of the following to tune performance of systems to support time-critical operations?

a) Denormalization

b) Redundant optimization

c) Optimization

d) Realization

Answer:a

Explanation:The process of taking a normalized schema and making it nonnormalized is called denormalization.



53. The lexical analyzer takes_________as input and produces a stream of_______as output.

a) Source program, tokens

b) Token, source program

c) Either of the two

d) None of the mentioned

Answer: a

Explanation: As per the definition of Lexical Analyser which states that lexical analysis is the process of converting a sequence of characters into tokens.



54. Parsing is also known as

a) Lexical Analysis

b) Syntax Analysis

c) Semantic Analysis

d) Code Generation

Answer: b

Explanation: Parsing or syntactic analysis is the process of analysing a string of symbols and conforming to the rules of grammar.



55. A compiler program written in a high level language is called

a) Source Program

b) Object Program

c) Machine Language Program

d) None of the mentioned


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