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] 2. Briefly describe two techniques for managing IO in a computer. [4] 3. What is cache memory? [4] 4. In a CPU what is the function of the Control Unit (CU)? [4] 5. 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] 2. Briefly describe the disk storage technique known as RAID. [2] 3. What is a file extension? How they are used by an operating system? [2] 4. 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] 5. What is the difference between a binary and a text file? [2] 6. 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] 2. 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] 3. What is search engine optimisation? What things can you do to a website in order to improving the website’s search engine ranking? [3] 4. 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]. 5. 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] 2. Convert the hexadecimal number ABC into decimal. [2] 3. What are the results of the following bitwise operations on 8-bit variables with no carry: a. 15 OR 31 b. 15 AND 31 c. NOT 15 d. 255 XOR 16 [8] 4. Why was Unicode invented? [3] 5. 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] 2. Describe two data structures with which you are familiar. [4] 3. 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] 4. 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]