Computing Scholarship 2014

Answer all questions

2 hours

Each section is worth 20%.

Section A - Computer Architecture and Operating Systems

  1. List four output devices. [4]
  1. Briefly describe two techniques for managing IO in a computer. [4]
  1. What is cache memory? [4]
  1. In a CPU what is the function of the Control Unit (CU)? [4]
  1. What is the function of the kernel of an operating system? [4]

Section B – Files and File Systems

  1. What is the difference between lossless and lossy file compression?[4]
  1. Briefly describe the disk storage technique known as RAID. [2]
  1. What is a file extension? How they are used by an operating system? [2]
  1. Explain what is meant by a sequential file, and describe how records are added and how records are deleted from a sequential file. Why is an indexed sequential file often used in preference to a standard sequential file? [5]
  1. What is the difference between a binary and a text file?[2]
  1. Records within a file can be fixed length or variable length. Describe the difference between fixed and variable length records. Give an advantage and disadvantage of variable length records. [5]

Section C – The Internet, Networking and Security

  1. Briefly explain the meaning of the following terms:
  • HTTP
  • IP
  • HTML
  • WWW

In each case your answer should specify what the letters in the term stand for as well as a brief explanation of the technology being referenced. [8]

  1. Routers are used in computer networks. Explain what is meant by the term router and describe the function of a router in a computer network. [3]
  1. What is search engine optimisation? What things can you do to a website in order to improving the website’s search engine ranking? [3]
  1. Explain what is meant by circuit switching and packet switching in a computer network and give one advantage of packet switching over circuit switching.[3].
  1. Describe the TCP/IP layered protocol model. [3]

Section D - Data Representation and Computer Logic

  1. Convert the binary number 1001 0111 into decimal. [2]
  1. Convert the hexadecimal number ABC into decimal. [2]
  1. What are the results of the following bitwise operations on 8-bit variables with no carry:
  1. 15 OR 31
  2. 15 AND 31
  3. NOT 15
  4. 255 XOR 16 [8]
  1. Why was Unicode invented? [3]
  1. Explain how the two’s complement system can be used to represent negative integer values. Illustrate your answer with an example. [5]

Section E – Programming

  1. Procedural programs are constructed using sequencing, iteration and selection. Explain the meaning of these three terms.[6]
  1. Describe two data structures with which you are familiar.[4]
  1. Briefly explain the terms below as they are used in object oriented programming:
  • Encapsulation
  • Classes
  • Methods
  • Inheritance

You may illustrate your answer with examples from any object oriented language with you are familiar. [4]

  1. Write a program in any language with which you are familiar to display the first n Fibonacci numbers. The value of n should be supplied at run-time by the user.

Output for the program should resemble the following:

Fibonacci Numbers

*****************

How many Fibonacci numbers do you wish to generate? :> 10

The first ten Fibonacci numbers are 1, 1, 2, 3, 5, 8, 13, 21, 34, 55

The rule for generating Fibonacci numbers is simple: the first two numbers in the Fibonacci sequence are 1 and 1, and then each subsequent number is the sum of the previous two.

Indicate which programming language you have used. [6]