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.  2. Briefly describe two techniques for managing IO in a computer.  3. What is cache memory?  4. In a CPU what is the function of the Control Unit (CU)?  5. What is the function of the kernel of an operating system?  Section B – Files and File Systems 1. What is the difference between lossless and lossy file compression?  2. Briefly describe the disk storage technique known as RAID.  3. What is a file extension? How they are used by an operating system?  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. What is the difference between a binary and a text file?  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.  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.  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. What is search engine optimisation? What things can you do to a website in order to improving the website’s search engine ranking?  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. . 5. Describe the TCP/IP layered protocol model.  Section D - Data Representation and Computer Logic 1. Convert the binary number 1001 0111 into decimal.  2. Convert the hexadecimal number ABC into decimal.  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  4. Why was Unicode invented?  5. Explain how the two’s complement system can be used to represent negative integer values. Illustrate your answer with an example.  Section E – Programming 1. Procedural programs are constructed using sequencing, iteration and selection. Explain the meaning of these three terms.  2. Describe two data structures with which you are familiar.  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. 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.