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 teach