ACSBR 2020 Computing P1 with solution

This paper has 13 pages, inclusive of the cover page. Name: Class: 4S3 Index Number: Anglo-Chinese School (Barker Road) PRELIMINARY EXAMINATION 2020 SECONDARY FOUR EXPRESS COMPUTING PAPER 1 7155/01 2 HOURS INSTRUCTIONS TO CANDIDATES: Do not open this booklet until you are told to do so. Write your name and index number clearly in the spaces at the top of this page. Write in dark blue or black pen. You may use soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Approved calculators are allowed. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part of question. You should show all your working. The total mark for this paper is 80. TOTAL 80

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 2 Secondary 4 Express Computing 7155/01

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 3 Secondary 4 Express Computing 7155/01 1 The diagram show four types of computer or network identifiers and six types of representation on the right. Draw one line between each identifier to its correct representation. Identifiers Representation • sequence of six hexadecimal numbers, one for each byte of the address, separated by hyphens or colons IPv4 • • two byte number assigned in a range from 0 to 65,535. Media Access Control (MAC) • • sequence of four denary numbers, one for each byte of the address, separated by dots. Port • • sequence of three bytes, one for each component SSID • • thirty-two byte string • sequence of sixteen hexadecimal digits, one for each byte of the address, separated by dots. [4]

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 4 Secondary 4 Express Computing 7155/01 2 (a) Convert the binary number 1011 1101 into a positive whole denary number. [1] (b) In a signed byte, the leftmost bit in one byte of data can be used as a sign bit, i.e. 0 or 1 to represent positive or negative numbers respectively. State the biggest positive whole denary number that can be represented by one signed byte of data. [1] 3 Memory addresses can be represented in hexadecimal codes. (a) 6EF50A50 is an example of a hexadecimal memory address. Complete the table below to convert each unique hexadecimal digit to its binary value. Hexadecimal 6 E F 5 0 A Binary ………… ………… ………… ………… ………… ………… [3] (b) Convert the denary number 1258 into hexadecimal number. Show your working. [2] (c) Explain why hexadecimal numbers are commonly used to represent binary numbers. [1]

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 5 Secondary 4 Express Computing 7155/01 4 (a) Draw the logic circuit to represent the following Boolean statement. Do not simplify the statement. X = NOT A OR (B NOR C) NAND (A OR C) A B C X [4] (b) Complete the truth table for the Boolean statement: X = NOT A OR (B NOR C) NAND (A OR C) A B C Working space X

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 6 Secondary 4 Express Computing 7155/01 [4] 5 Technology is currently an area of growth in the financial industry. (a) Give two benefits to the consumers of using technology to manage their finances. 1 2 [2] (b) It is imperative that financial institutions are secured against cyberattacks. Describe the following terms and how they could be used in cyberattacks. Pharming Malware [4] 6 There are different types of software licenses. (a) FOSS stands for software. [1] (b) Proprietary software can be categorised as freeware or shareware. State one similarity and difference between the two types of software. Similarity Difference

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 7 Secondary 4 Express Computing 7155/01 [2] 7 Computers need to process data and follow instructions. (a) CPU stands for . [1] (b) Describe and state the function(s) of the following parts found in the CPU. Arithmetic Logic Unit Control Unit [2] (c) (i) Explain the use of a bus in a computer. [1] (ii) State the two types of buses found in a computer. 1 2 [1]

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 8 Secondary 4 Express Computing 7155/01 8 A local university is located on two campus within a city. It has a computing network to facilitate data transfer. (a) Identify the geographical network of the university. [1] (b) State two advantages of a computer network. 1 2 [2] (c) State two disadvantages in using a computer network. 1 2 [2] (d) The university deploys a hybrid system of wired and wireless networks. Describe one possible use of each network and explain why it is used. Wired network Wireless network [4]

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 9 Secondary 4 Express Computing 7155/01 9 The Grade Point Average (GPA) of a group of students are shown in a spreadsheet. (a) State the type of data that is held in each of the following cells. A2 D8 E3 [3] (b) The year of admission in Column C can be taken from the first four digits of the Student ID in Column B. Identify the most appropriate function that will need to be entered in cell C2. [1] (c) Cell B14 needs to display the highest GPA. Identify the most appropriate function that will need to be entered in cell B14. [1] (d) Cell B15 needs to display the number of students who has a GPA above 4. Identify the most appropriate function that will need to be entered in cell B15. [1] (e) Cells E2 to E12 need to display a red background if the number is less than 3. State how the cells can be set to automatically change colour depending on the values inside them. [1]

Anglo-Chinese School (Barker Road) Preliminary Examination 2020 10 Secondary 4 Express Computing 7155/01 10 A programmer is designing a point of sale (POS) system for a retail store. He wants to write an algorithm that calculates the total cost a customer has to pay for shopping at a retail store. Customers who are members of the store’s loyalty program gets a 5% discount. (a) The algorithm requires a number of input variables, e.g. number of items, cost of each item, member’s name and validity of membership etc. Tick (✔) one box to identify the most appropriate data type for each variable. Variable String Integer Float Boolean member_name valid_membership number_of_items cost_of_each_item [4] (b) State the output(s) and the processes required to find the total cost of a customer’s shopping. Output(s): Processes required: [4]