CSS Computer Science Past Paper 2018

Instructions specific to this paper

• Attempt ONLY FOUR questions from PART-II by selecting TWO questions from EACH
• Attempt ONLY FOUR questions from PART-II by selecting TWO questions from EACH

Questions

1. Q. 24 marks

   (a) How many layers are in the TCP/IP stack? What are the names? (b) How digital evidences can be preserved from a crime scene. Write in details by taking (4) examples of digital devices commonly used these days. (c) What are the responsibilities of Operating system kernel? (3) (d) List down any four best practices for coding standards. (3) (e) Why do modern processors use more power when their clock frequency is increased? (2) (f) Ali is telling Ahmad that he is representing a -ve number and its most significant bit is 1, (2) Ahmad immediately shouted you are representing numbers using 2's compliment. True or False. And why? (g) If time slice is of 50 milliseconds and context switch requires a microsecond, how many (2) processes can the machine service in a second?

2. Q. 36 marks

   (A) Differentiate between hub, bridge, switch and router. (8) (B) Discuss how Network Address Translation (NAT) works and why is it useful? (C) Elaborate the working of multiplexing/de-multiplexing at the transport layer. (6)

3. Q. 45 marks

   Consider the inheritance hierarchy shown below. Each part of this question is independent. (a) In which class(es) would it make most sense to have protected members? Which class(es) would be able to access those protected members directly? (b) Which class(es) can access private members of class C directly? (5) (c) Suppose class C contains a pure virtual function. Suppose we wish to instantiate objects of (5) this hierarchy. Which class(es) are or could be abstract and which are concrete? (d) Consider the following list of classes: Car, SteeringWheel, Vehicle, Van, Minivan, (5) AudioSystem, ParkingLot. Your task is to describe all of the is-a and has-a relationships between these classes. Include an inheritance hierarchy for all classes that fit. Fill in the table with is-a or has-a relationship while leaving the cells empty where no relation is applicable. Mini Steering Audio Parking Vehicle Car Van Van Wheel System Lot Vehicle Car is-a Van Mini Van Steering Wheel Audio System Parking Lot

4. Q. 53 marks

   (a) What is dangling pointer? (b) What data structure would employ to build a text editor and why? (5) (c) Random insertion of nodes into a binary search tree would result in what types of tree (7) shape. Elaborate. (d) How would you modify a link list based queue so that first and last node can be accessed (5) in a constant time regardless of data nodes in the queue?

5. Q. 65 marks

   (a) Define balanced tree both for AVL and Binary search tree. (4) (b) What is informed or heuristic search what type of algorithm is used to do such a search? (6) (c) Differentiate between graph and trees. Which is special case of the other? (d) Explain what type of problems can be solved by genetic algorithm. (5)

6. Q. 74 marks

   (a) Outline the difference between software verification and software validation. (b) Give an outline of the unit testing process for verification. (4) (c) Agile Development is a process that values responding to change over following a plan. (4) Discuss three issues a Software Engineer should be mindful of when adopting this approach during software development. (d) What type of project is not suited to incremental methods? (4) (e) Outline the difference between Black box and White box testing. (4)

7. Q. 85 marks

   (a) What is the difference between lexers and parsers? (b) Write a grammar (BNF) for the language of palindromes. (5) (c) Here DFA is given for the language L find the DFA for L2 (5) (d) Convert the following DFA to a RE: (5)

Standard FPSC instructions

Printed on this and every CSS paper.

• Part-II is to be attempted on the separate Answer Book.
• All the parts (if any) of each question must be attempted at one place instead of at different places.
• Write Q. No. in the Answer Book in accordance with Q. No. in the question paper.
• No page/space be left blank between the answers. All the blank pages of the Answer Book must be crossed.
• Extra attempt of any question or any part of the attempted question will not be considered.