2021 SST S4 Computing Prelim P1 QP final

SECONDARY 4 PRELIMINARY EXAMINATION COMPUTING Paper 1 Written 7155/01 27 August 2021 (Friday) 2 hours CANDIDATE NAME CLASS INDEX NUMBER READ THESE INSTRUCTIONS FIRST Do not turn over the page until you are told to do so. Write your name, class, and index number in the spaces provided above. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. Approved calculators are allowed. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. You should show all your working. The total number of marks for this paper is 80. This document consists of 18 printed pages, including this Cover Page. For Examiner’s Use 1 8 2 3 3 6 4 6 5 4 6 10 7 6 8 14 9 9 10 6 11 8 Total /80

Page 2 of 18 1 (a) Computers use collections of wires called buses to transport data from one part of the computer to another. Draw one or more lines from each type of bus on the left to the description that applies to it on the right. Type of bus Description Transports information from memory to processor when reading data from memory Data bus Transports information from memory to processor when writing data to memory Transports information from processor to memory when reading data from memory Address bus Transports information from processor to memory when writing data to memory [2] (b) Computers also require one or more hardware devices for input and output. (i) State what is meant by an input device. ……………………………………………………………………………… ……………………………………………………………………………… [1] (ii) Besides the mouse and keyboard, name two input devices that are required when making a video conference call on a computer. ……………………………………………………………………………… ……………………………………………………………………………… [2]

Page 3 of 18 [Turn over (c) The operating system of a computer is usually stored on its hard drive. However, its data and instructions are loaded into the random access memory (RAM) after booting up the computer. (i) Suggest why the operating system is not stored in the RAM. ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… [2] (ii) Explain why the operating system's data and instructions are loaded into the RAM instead of the read-only memory (ROM) after booting up the computer. ……………………………………………………………………………… ……………………………………………………………………………… [1] 2 IP and MAC addresses are used to identify individual computers so that data transmitted over a network can be directed to the correct destination. The table contains statements about IP and MAC addresses. Tick (ü) one or more boxes in each row to indicate if the statement is about IPv4, IPv6 or MAC addresses. Statement IPv4 Address IPv6 Address MAC Address Also known as a physical address. Used to direct data transmitted over the Internet to a device. Used by a switch to forward data to the intended recipient device. Represented by more than 4 bytes. Usually represented in hexadecimal. [3]

Page 4 of 18 3 Technology has made it easy for people to remain connected and communicate with one another no matter where their physical location is. (a) Give one social benefit and one social drawback of using technology to communicate. Benefit ………………………………………………………………………….. …………………………………………………………………………………... Drawback ……………………………………………………………………….. …………………………………………………………………………………... [2] (b) The rise of the use of social media to share original content such as photos and videos has also led to an increase in plagiarism and violation of intellectual property rights. (i) Define the term intellectual property. ……………………………………………………………………………… ……………………………………………………………………………… [1] (ii) Plagiarism is often confused with copyright infringement. By comparing the difference between plagiarism and copyright infringement, conclude whether a social media influencer who uploads a public domain photo onto his own social media account and pretends it was taken by himself is guilty of plagiarism, copyright infringement, or both. ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… [3]

Page 5 of 18 [Turn over 4 Malicious software, or malware, refers to software that is intentionally used to damage, disrupt or gain unauthorised access to a computer system. (a) Name two types of malware and describe their distinguishing features. Malware 1 ………………………………………………………………………. Description ……………………………………………………………………… …………………………………………………………………………………... …………………………………………………………………………………... Malware 2 ………………………………………………………………………. Description ……………………………………………………………………… …………………………………………………………………………………... …………………………………………………………………………………... [4] (b) Explain the role of updating software regularly in preventing attacks from malware. …………………………………………………………………………………... …………………………………………………………………………………... …………………………………………………………………………………... …………………………………………………………………………………... [2]

Page 6 of 18 5 Web addresses follow the syntax rules of a Uniform Resource Locator (URL) so that a web browser can extract various pieces of information from it. A web address may contain several reserved characters that need to be URL encoded. URL encoding comes in the form "%XX", where XX are hexadecimal digits. (a) State what the hexadecimal digits in the URL encoding represent. …………………………………………………………………………………... …………………………………………………………………………………... [1] (b) The URL encoding for the semicolon character (";") is %3B. Convert the number into denary. …………………………………………………………………………………... …………………………………………………………………………………... [1] (c) The URL encoding for the right curly brace ("}") is %7D. Convert the number into a 2-byte binary number. Answer ……………………………………………………………………… [2]

Page 7 of 18 [Turn over 6 Mr Yeo is the founder of a new company, SSTea Inc, which sells bubble tea and offers discounts to customers who are registered on their membership programme. He wants to set up a company network for his head office that allows him and his four employees to share files easily and yet is secure from external threats. Mr Yeo has plans to hire more employees as he sets up more retail stores. (a) When setting up a firewall for his network, Mr Yeo considers the option to configure it such that a private network is set up. While a private network is secure from external threats, it is still vulnerable to internal threats. (i) State the purpose of a firewall. ……………………………………………………………………………… ……………………………………………………………………………… [1] (ii) Describe the ethical principles that the employees must abide by to ensure the security of a private network from within. ……………………………………………………………………………… ……………………………………………………………………………… [1] (b) Mr Yeo must also decide between using a wired or wireless setup for his head office. (i) By considering the needs of Mr Yeo's office and comparing each type of network, suggest which one he should choose. ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… [2] (ii) Give one disadvantage of the type of network you have suggested in part (i). ……………………………………………………………………………… ……………………………………………………………………………… [1]

Page 8 of 18 (c) Complete the following paragraph by filling in the missing words. A/an ……………………………………… should be connected to a modem. This device forwards packets between the office network and the Internet. The ……………………………………… of the