DHS 2024 Y6 H2 Computing Prelim Paper 1 final

This document consists of 6 printed pages. Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 COMPUTING (Higher 2) 9569/01 Paper 1 Written 18 September 2024 3 hours READ THESE INSTRUCTIONS FIRST Write your name, index number and class on the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all the questions. Approved calculators are allowed. You are reminded of the need for good English and clear presentation in your answers. Please ask the invigilator if you require additional paper. The number of marks is given in brackets [ ] at the end of each question or part question. The total number of marks for this paper is 100. [Turn over

2 DHS 2024 Year 6 H2 Computing Preliminary Examination Paper 1 1. The rules that are used when deciding whether to offer insurance to customers and whether to offer discounts are as follows: • If the customer has been refused insurance by another company and their car is over 10 years old then insurance is refused. • If the customer has been refused insurance by another company and their car is not more than 10 years old then insurance without any discount is available. • If the customer has not been refused insurance by another company and their car is over 10 years old then insurance without any discount is available. • If the customer has not been refused insurance by another company and their car is less than 10 years old and they have made not more than three claims previously then insurance with a discount is available. (a) Copy and complete the decision table showing all the possible outcomes and results.[4] (b) Simplify your decision table by removing redundancies. [2] 2. Guests stay at holiday homes in the Changi Holiday Park for a week at a time. When a guest wants to book an activity (swimming, dining, etc), a computer-based activity booking system will be used. It will contain all the information described below. It will allow guests to book their activities on the Changi Holiday Park 's intranet. When a booking is made, the following details are always required: • hNo: holiday home number, e.g., 02-14: room 14 of level 2 • aCode: code of activity, e.g., D1800 The following are also required: • sGuest: Status of guest. (M) Member, (N) Non-member • nVisits: Number of visits for member • nmVoucher: a e-voucher worth $2 will be given to non-member for each activity Member will be given 10% discount if number of visits is more than 5 times. (a) Draw a diagram that shows suitable classes and their relationships for a solution to different payment type for guests of different activity that uses OOP techniques. Include appropriate attributes and methods in each class. [6] Discuss the following with the class diagram from (a) and the appropriate attributes and methods in each class. (b) What are the benefits of using OOP? [2] Condition 1 2 3 4 5 6 7 8 Has customer been refused insurance by another company? Is car over 10 years old? Has customer make more than 3 claims previously? Action

3 DHS 2024 Year 6 H2 Computing Preliminary Examination Paper 1 (c) The three key features of the object-oriented approach are often quoted as: [6] (i) Encapsulation (ii) Inheritance (iii) Polymorphism What do these three features mean? 3. Decomposition and modularity are important concepts in software development. Explain what they mean and how do they benefit in software development. [4] 4. The following questions are not related to each other. (a) State the meaning of privacy of data. [1] (b) State the meaning of integrity of data. [1] (c) What is the difference between back up and archive? [1] (d) What is the advantage of version control in software development? [2] 5. A bank has a number of offices all over the world. Each office has a local area network (LAN). The LANs are connected together to create a wide area network (WAN) for use by its staff. A Local Area Network (LAN) contains a number of devices: • a router • twenty laptop computers • a server. (a) The server has the IP address 192.168.3.2 Explain why this is not an IPv6 address. [2] (b) The LAN is set up as a star topology as follow: Describe the function of a router in the network. [2] (c) Explain how data is transmitted between the two laptops in the LAN. [2] (d) What does protocol define in computer networks? [2] (e) Explain the importance of protocol in computer network. [2] [Turn over

4 DHS 2024 Year 6 H2 Computing Preliminary Examination Paper 1 (f) Explain the TCP/IP model and the function of each layer with examples. [4] (g) A new online (web) form is to be designed to gather data from customers. Describe the features that must be considered when designing a new form. [3] (h) Explain with any two techniques how the bank could use encryption techniques to attempt to prevent its data from being read by unauthorised people. [2] (i) Identity theft means one of the following: • Unauthorised use of personal information so that perpetrator can pretend to be another person/use their identity • Using the information (in an unauthorised manner) for personal gain • Using the information to cause harm/loss/disadvantage to victim • Combining valid identity data with false/fabricated data to create a new/synthetic identity. Describe two impacts of identity theft on individuals. [2] 6. (a) Describe, with the aid of a diagram, the data structure called a linked list. [4] (b) Describe, with the aid of diagrams, an algorithm to add a new data item into the linked list, so that this new data item occupies position n. You may assume that the linked list contains at least n - 1 items before the addition. [6] (c) An alternative type of list structure is one whose data items are always held in a contiguous area of store (an array). Give one advantage and one disadvantage that this has over the linked list organisation. [2]

5 DHS 2024 Year 6 H2 Computing Preliminary Examination Paper 1 7. A stack Abstract Data Type (ADT) is to be implemented using pseudocode, with procedures to initialise it, to push new items onto the stack and pop an item from stack. A 1D array Stack stores the decimal numbers of the stack. CONSTANT MaxSize = 40 DECLARE BasePointer : INTEGER // Points to the bottom of the stack DECLARE TopPointer : INTEGER // Points to the top of the stack DECLARE Stack : ARRAY[1:40] OF REAL // initialisation of stack PROCEDURE Initialise() BasePointer  1 TopPointer  0 ENDPROCEDURE (a) Copy and complete the pseudocode procedure Push() to push an item into Stack. [3] // adding an item onto the stack PROCEDURE Push(NewItem : REAL) : : ENDPROCEDURE (b) Copy and complete the pseudocode function Pop() to pop an item from Stack. [5] // popping an item from the stack FUNCTION Pop() : : ENDFUNCTION (c) Justify the use of a linked list instead of an array to implement a stack. [2] (d) Explain how to make use of a stack when translating recursive programming code. [3] (e) Compare and contrast the queue and stack Abstract Data Types (ADT). [3] 8. The location of a record in a random file is determined using a hashing algorithm. A collision may occur during the process of adding a record. (a) Outline what is meant by the term collision in this context. [2] (b) Explain how a collision can be dealt with when writing records to