BLSS 2018 Computing P1

BOON LAY SECONDARY SCHOOL PRELIMINARY EXAMINATION 2018 Name ( ) Class Subject : COMPUTING Paper No : 1 Subject Code : 7155/01 Level : SECONDARY FOUR EXPRESS Date/Day : 18 SEPTEMBER 2018 (TUESDAY) Time : 0800 – 1000 Duration : 2 HOURS Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Before you start your exam, check that you have received the correct paper and the number of printed pages are correct. Write your name, index number and class in the spaces at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, 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 question. You should show all your working. The total number of marks for this paper is 80.

2 [Turn over This document consists of 12 printed pages. 1 A computer system stores and retrieves data from a few types of memory. Name three types of memory that are commonly found in a computer system and describe each of them in terms of their speed, size, and/or location. Type 1…………………………………………………………………………..…………...…… Description……………………………………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… Type 2…………………………………………………………………………..…………...…… Description……………………………………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… Type 3…………………………………………………………………………..…………...…… Description……………………………………………………………………..…………...…… ...........…………………...……………………………………………………...……..………[6] 2 (a) A network is to be setup to allow internet access in the school canteen. Mr Tan is considering between setting up a wired, or a wireless network. Describe two differences between wired and wireless networks. Difference 1…….……………………………………………………..………….....…… ..……………………………………………………………………………..…………..... ..……………………………………………………………………………..…...……….. Difference 2…….……………………………………………………..………….....…… ..……………………………………………………………………………..…………..... ..……………………………………………………………………………..…...…..…[2] (b) What advantage and disadvantage does wireless networks have compared to wired networks for the case in part(a)? Advantage….……………..…………………………………………..………….....…… ..……………………………………………………………………………..…………..... ..……………………………………………………………………………..…...……….. Disadvantage……………..…………………………………………..………….....…… ..……………………………………………………………………………..………….....

3 [Turn over ..……………………………………………………………………………..…...…..…[2] 3 The spreadsheet data below shows the contributions of students for a class party. (a) Write down a formula that will count the number of students who are bringing more than 2 family members. = ..…………………………………………………………………………..…...…..…[2] (b) Write down a formula that has been entered in cell C4 and has been used to complete the calculation for column Amount. Note that the student will have to contribute as well. = ..…………………………………………………………………………..…...…..…[2] (c) Name the data type for column Name and column Amount. Data type for Name ……..…………………………………………..………….....…… Data type for Amount …..…………………………………………..………….....…[2]

4 [Turn over 4 (a) Write down the largest possible value for a one-byte binary number. Convert it to a denary number. Show your working. ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[2] (b) Convert the hexadecimal number B3 into a binary number. Show your working. ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[2] (c) Convert the denary number 26 into a binary number. Show your working. ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[2] 5 Unauthorised access occurs whenever data owned by someone is used by someone else, such as an intruder, or an unknowing individual, without permission. (a) State two reasons why unauthorised access occurs. Reason 1...……………………………………………………………..…………...…… ....………………………………………………………………………..…………...…… Reason 2...……………………………………………………………..…………...…… ...........……………………………………………………………………………….…[2] (b) Describe two safety measures to prevent unauthorised access. Safety measure 1.……………………………………………………..…………...…… ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… Safety measure 2.……………………………………………………..…………...…… ....………………………………………………………………………..…………...……

5 [Turn over ...........……………………………………………………………………………….…[2] 6 Across the world, the music, television and film industries have been hit hard by acts of piracy. (a) Describe two economic effects on the music and film industries if piracy is not curbed. 1..………………………………………………………………………..…………...…… ....………………………………………………………………………..…………...…… 2.........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[2] (b) Siti enjoys watching a television series that is only available on an online video site. After some research, she realises that she can download the television series onto her computer hard drive so that she can watch the videos without going online. Explain why her act is considered copyright infringement. ....………………………………………………………………………..…………...…… ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[1] (c) Describe a situation where music can be downloaded legally without copyright infringement. ....………………………………………………………………………..…………...…… ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[1] 7 (a) Describe what is meant by data validation in programming. ....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..………… ...........……………………………………………………………………………….…[2] (b) Name two common checks that are performed in data validation.

6 [Turn over 1.........…………………………………………………………………………..………… 2.........……………………………………………………………………………….…[2] 8 Insert four of the following words about data flow in the correct place in the text below. an input device an output device processor register ALU ROM control unit When using input and output devices, the following data flow may occur. ● The data is entered using …...…………………………...….. and converted into a form that the computer can understand. This data may be temporarily stored in a …...…………………………...…… ● Instructions from the running application are interpreted by the …...…………………………...…… These instructions may request the data to be processed by the …...…………………………...….. . [4] 9 A shop owner wants to use a computer to find out the bestselling title in 2017. There were 480 books titles for sale in 2017 and the number of copies sold for each book title was different. State the inputs, the outputs and processes required to find the title of the bestselling book and the number of copies sold for this title. Inputs.....………………………………………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… Outputs..………………………………………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… Processes required ….…………….………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… ...........…………………………………………………………………………..…………...…… ...........…………………...……………………………………………………...……..………[6]

7 [Turn over 10 An algorithm is required to retrieve up to 20 numbers stored from an array and add them together. It stops reading the data, and output the total when the total exceeds 100. The input is provided in an array called “Number” and the output is pr