2022 MSHS S4 Prelims Paper 1 Answers_final

Class/ Index Number / Centre Number/ ‘O’ Level Index Number / Name MARIS STELLA HIGH SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR COMPUTING 7155/01 Paper 1 Written 23 August 2022 2 hours Candidates answer on the Question Paper. No Additional Materials are required. MARKING SCHEME For Examiner’s Use This document consists of 16 printed pages. 80

2 1 Five data loss issues are shown on the left. Six possible methods of data recovery or protection are shown on the right. Draw one line to link each issue to its correct method . Data Loss Issues Methods Data loss caused by hard disk head crash Anti-virus software Hacking into files and changing or deleting data Encryption A computer program that attaches itself to a harmless program and modifies it Read policy privacy An intruder with physical access to a storage device accessing files or folders Anti-spyware software Software that logs/records all key presses on your computer without you knowing Create back-up files Use of passwords and firewall [5]

3 2 There are five stages in developing a program. Identify three stages and elaborate the process of each stage. 1 mark to identify the stage, 1 mark for explaining what happens at that stage 1 – Gather Requirements • Determine the nature of the problem by interviewing the intended audience of the program • Identifying a set of input necessary and how input will be collected • Identifying what outputs are required and how output will be given 2 – Plan Solutions • Manually solving different simplified examples of the problem and generalising the steps needed to produce the required output (apply generalising to solve problem and plan solution) • Trying different ways to break down the problem into smaller parts such that the intended output of each part gets closer and closer to what is needed to solve the problem(apply decomposition to solve problem and plan solution) • Comparing the problem to other problems that have been solved before and identifying which algorithms can be used. • Estimating the amount of effort needed to write the code or the time needed to complete the algorithm before making a definite choice ( plan logistics and project timeline) • Writing possible algorithms using either flowcharts or pseudo-code 3 – Write code • Write code that performs the algorithm as planned in the previous stage as efficiently as possible. 4 – Test and Refine Code • Running the code through one or more test cases to evaluate whether the written code adequately satisfies the gathered requirements and is ready to be used. 5 – Deploy Code • To allow program to be used by intended audience by training users to use the program. • Transitioning from an old program or sys