SST 2020 S4 Computing P1

SECONDARY 4 PRELIM EXAMINATION COMPUTING Paper 1 Written 7155/01 28 August 2020 (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. 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. For Examiner’s Use 1 4 2 9 3 4 4 5 5 4 6 5 7 7 8 4 9 8 10 10 11 6 12 9 13 5 Total /80

Page 2 of 18 1 Draw a line to match the computer parts to their correct description. [4] Computer Parts arithmetic logic unit • address bus • control unit • data bus • process register • RAM • ROM • Description • Data storage space that is extremely fast but small. It is physically located inside the processor and cannot be changed without changing the processor. • Transports required memory location from processor to memory; uni-directional. • Where data and instructions are stored temporarily so that they can be quickly accessed by the processor when needed. • Part of the processor that follows instructions and decides when data should be stored, received or transmitted by different parts of the computer. 2 The hexadecimal numbering system is widely used in computing. Some examples of usage include representing common characters in the ASCII code format, as well as network addresses such as the Internet Protocol (IP) addresses. (a) State what the acronym “ASCII” stands for. ……………………………………………………………………………………… [1] (b) The character “|” is represented by the hexadecimal number 7C in ASCII. Convert 7C into a binary number. Show your working. Answer: …………………………………… [2]

Page 3 of 18 [Turn over (c) The backslash character “\” is represented by the binary number 1011100 in ASCII. Convert 1011100 into a denary number. Show your working. Answer: …………………………………… [2] (d) The character “m” is represented by the denary number 109 in ASCII. Convert 109 into a hexadecimal number. Show your working. Answer: …………………………………… [2] (e) Two well-used IP addresses systems are IPv4 and IPv6 addresses. State the number of bytes an IPv4 address and an IPv6 address use respectively. Answer: IPv4 uses …..………………. bytes IPv6 uses …….……………. bytes [2]

Page 4 of 18 3 The rise of technology and the internet has transformed the education landscape in Singapore. The Ministry of Education reports that more schools have experimented with technology for learning and teaching. More research is also being done to develop ICT innovations that can be adopted by schools.1 However, the use of technology in education also comes with its own threats. (a) State one positive and one negative social impact of technology on education. (i) Positive impact ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (ii) Negative impact ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... [1] [1] (b) Viruses and worms are two examples of cyberattacks. State a similarity and a difference between viruses and worms. (i) Similarity ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (ii) Difference ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... [1] [1] 1 https://www.straitstimes.com/singapore/education/more-schools-tap-tech-tools-for-learning (Accessed in August 2020)

Page 5 of 18 [Turn over 4 Data can be lost or stolen due to unauthorised access by individuals or groups. (a) The table below shows some measures to prevent unauthorised access to data. Classify these measures by putting a tick (✓) in the most appropriate category for each row. Measures Access Control / Authorisation Authentication Understanding of Private Policies Biometrics Cloud Services Encryption Firewalls Passwords Social Networking sites [3] (b) State what 2FA stands for, and explain how it works to prevent theft of data. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... [2] 5 Boon Lay East Secondary School (BLESS) is organising a cross-country event for its 1000 students. It plans to use a computerised system to find the fastest runners for girls and for boys. State the inputs and processes required to find the name and the timing of fastest runner in each category. Inputs:………………………………………………………………………………. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Processes: ................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... [4]

Page 6 of 18 6 A company is building a new office. They need to build a wireless computer network from scratch. Each employee will be equipped with a desktop and must be able to connect to the internet easily. (a) Give two reasons why the company is building a computer network as opposed to setting up stan