Cambridge A Level Computer Science 9608 — 2018 May/June Paper 1 · Variant 3

This document consists of 15 printed pages and 1 blank page. DC (NH/SW) 144489/2 © UCLES 2018 [Turn over * 6 1 8 6 1 5 1 0 2 7 * COMPUTER SCIENCE 9608/13 Paper 1 Theory Fundamentals May/June 2018 1 hour 30 minutes Candidates answer on the Question Paper. No Additional Materials are required. No calculators allowed. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name 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, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. No marks will be awarded for using brand names of software packages or hardware. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. The maximum number of marks is 75. Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level

2 9608/13/M/J/18 © UCLES 2018 1 A web page includes the following HTML and PHP code. 01 <?php 02 if(isset($_GET['mark'])) { 03 echo "Grade: " . calculateGrade($_GET['mark']); 04 } else { 05 ?> 06 07 <form action="#" method="get"> 08 Enter Mark: <input type="text" name="mark" /><br /> 09 <input type="submit" value="Calculate" /> 10 </form> 11 12 <?php 13 } 14 15 function calculateGrade($inputMark) { 16 $gradeChar = "U"; 17 if($inputMark >= 80) $gradeChar = "A"; 18 else if($inputMark >= 70) $gradeChar = "B"; 19 else if($inputMark >= 60) $gradeChar = "C"; 20 else if($inputMark >= 50) $gradeChar = "D"; 21 else if($inputMark >= 40) $gradeChar = "E"; 22 return $gradeChar; 23 } 24 ?> (a) Give the identifier of two variables used in the PHP code. Identifier 1 … Identifier 2 … [2] (b) Give the line number where the PHP code produces an output. …[1] (c) Describe the purpose of the expression $_GET['mark'] in line 03. … … … …[2] (d) State whether this PHP code will run client-side or server-side. …[1]

3 9608/13/M/J/18 © UCLES 2018 [Turn over 2 A company writes applications (apps) for smartphones. The company has a relational database, PURPLEGAME, which stores the information for one of its online game apps. The database has three tables to store player’s details, dates when they have logged into the app and in-app purchase details. LOGIN(LoginID, PlayerID, Date) PURCHASE(PurchaseID, PlayerID, PurchaseDate, Cost) PLAYER(PlayerID, PlayerName, SkillLevel) (a) Draw the entity-relationship (E-R) diagram to show the relationships between the three tables. [2] (b) The database manager is concerned about data integrity. State what is meant by data integrity. Give an example of how the manager can ensure data integrity in the PURPLEGAME database. … … … …[2]

4 9608/13/M/J/18 © UCLES 2018 (c) The database designer states that the PURPLEGAME database is in Third Normal Form (3NF). Tick (3) one box to indicate whether this statement is true or false. True False Justify your choice. … … … … … …[3] (d) (i) The following table shows some sample data for the PLAYER table. PlayerID PlayerName SkillLevel fly918 Kylie 3 elephant11 Mehrdad 9 candy22 Suzi 15 greenGrass Jason 22 Write an SQL script to create the PLAYER table. … … … … … … … … … …[5]

5 9608/13/M/J/18 © UCLES 2018 [Turn over (ii) The table, PLAYER, needs to be altered. A new field, DateOfBirth, needs to be added. Write an SQL script to add the DateOfBirth field to the PLAYER table. … … … …[2]

6 9608/13/M/J/18 © UCLES 2018 3 A computer is designed using the Von Neumann model. (a) Describe the role of the Arithmetic and Logic Unit (ALU) and Control Unit (CU) in the Von Neumann model. ALU … … … … CU … … … … [4] (b) Describe the role of the Status Register and Program Counter (PC). Status Register … … … … PC … … … … [4]

7 9608/13/M/J/18 © UCLES 2018 [Turn over (c) H is a register. The current contents of H are: 1 1 0 0 0 0 0 1 The current contents of register H represent an unsigned binary integer. (i) Convert the value in register H into denary. …[1] (ii) Convert the value in register H into hexadecimal. …[1] (iii) The current contents of register H represent a two’s complement binary integer. Convert the value in register H into denary. …[1] (iv) State why register H does not currently contain a Binary Coded Decimal (BCD). … …[1]

8 9608/13/M/J/18 © UCLES 2018 4 Parity bits can be used to verify data. (a) The following binary number is transmitted using odd parity. Add the missing parity bit. Parity bit 0 1 1 1 0 1 0 [1] (b) In the following parity block, the first column contains the parity bits, and the last row contains the parity byte. A device transmits the data using even parity. Circle the error in the data being transmitted. Parity bit Data 0 0 1 1 0 1 0 1 1 1 1 1 1 0 0 1 1 0 1 0 1 0 0 0 0 0 0 1 1 0 1 1 Parity byte 0 1 1 1 1 1 0 1 [1] (c) Four error detection measures are shown. Draw one line from each error detection measure to indicate whether it is verification or validation. Verification Validation Type check Proof reading Check digit Checksum Error detection measure [4]

9 9608/13/M/J/18 © UCLES 2018 [Turn over Question 5 begins on the next page.

10 9608/13/M/J/18 © UCLES 2018 5 (a) A student needs to design a logic circuit to model the requirements for membership of a snooker club. Membership (X) depends on four criteria, as shown in the table: Parameter Description of parameter Binary value Condition A Over 18 1 True 0 False B Recommended 1 True 0 False C Full-time 1 True 0 False D Retired 1 True 0 False Membership is approved (X = 1) if the person: • is over the age of 18 and has been recommended by a pre-existing member and • either is working full-time or is retired, but not both. Draw a logic circuit to represent the membership requirements. A B C X D [3]

11 9608/13/M/J/18 © UCLES 2018 [Turn over (b) Complete the truth table for the logic expression: X = (A XOR B) AND NOT C A B C Working space X 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 [4]

12 9608/13/M/J/18 © UCLES 2018 6 A black and white bitmap image is shown. (a) State the minimum number of bits needed to represent each pixel in this image. …[1] (b) Run-length encoding (RLE) is used to store the image with the following colour codes. Colour Code Black 1A White 3B Show how run-length encoding is used to store the image. … … …[3] (c) An image has 30 different colours. State the minimum number of bits needed to represent each pixel in the 30-colour image. …[1]

13 9608/13/M/J/18 © UCLES 2018 [Turn over (d) When the image is saved, a header is added to the file. State the purpose of the file header. Give two examples of the file header contents. Purpose … … Example 1 … … Example 2 … … [3] (e) Graphics software is used to edit a digital photograph. Give three features of graphics software that can be used to edit the photograph. Describe the effect each has on the photograph. Feature 1 … Effect … … … Feature 2 … Effect … … … Feature 3 … Effect … … … [6]

14 9608/13/M/J/18 © UCLES 2018 7 A zoo has a computer system for the visitors to access multimedia content about the zoo and its animals. (a) The users interact with the computer system through touchscreens. Describe the internal operation of a touchscreen. … … … … … … … … … …[4] (b) (i) Give one output device, other than a touchscreen, that may be part of this computer system. …[1] (ii) Give two input devices, other than a touchscreen, that may be part of this computer system. State how each device will be used by the visitors. Device 1 … Use … … Device 2 … Use … … [4]

15 9608/13/M/J/18 © UCLES 2018 (c) Give the most appropriate secondary storage device for this computer system. Describe two reasons for your choice. Device … Reason 1 … … … … Reason 2 … … … … [5] (d) This computer system has Random Access Memory (RAM) and Read Only Memory (ROM). State what will be stored in RAM and ROM for this computer system. RAM … … ROM … … [2]

16 9608/13/M/J/18 © UCLES 2018 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. BLANK PAGE

IGCSE™ is a registered trademark. This document consists of 9 printed pages. © UCLES 2018 [Turn over Cambridge Assessment International Education Cambridge International Advanced Subsidiary and Advanced Level COMPUTER SCIENCE 9608/13 Paper 1 Written Paper May/June 2018 MARK SCHEME Maximum Mark: 75 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2018 series for most Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 2 of 9 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors. GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind.

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 3 of 9 Question Answer Marks 1(a) 1 mark for each variable name $gradeChar $inputMark 2 1(b) 03 1 1(c) • Gets the value stored in the text box / input field “mark”... • To be used as a parameter in calculateGrade 2 1(d) Server-side 1 Question Answer Marks 2(a) 1 mark for each correct relationship 2 2(b) 1 mark for description • Ensure data is consistent / accurate // keep data consistent / accurate 1 mark for example from: e.g. • Validation rules • Referential integrity • Verification • Input masks • Setting data types • Removing redundant data • Backup data • Access controls • Audit trail 2 2(c) 1 mark for the correct box ticked True False 9 1 mark per bullet for justification, max 2 • No repeated attributes // data is atomic // No partial dependencies (no dual keys) • No non-key / transitive dependencies 3

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 4 of 9 Question Answer Marks 2(d)(i) 1 mark per bullet • CREATE TABLE PLAYER and (); • PlayerID and PlayerName as VARCHAR and commas • SkillLevel as INT and comma • PRIMARY KEY(PlayerID) • An appropriate NOT NULL CREATE TABLE PLAYER( PlayerID: varchar NOT NULL, PlayerName: varchar, SkillLevel: int, PRIMARY KEY(PlayerID), ); 5 2(d)(ii) 1 mark per bullet • ALTER TABLE PLAYER • ADD DateOfBirth Date; 2 Question Answer Marks 3(a) 1 mark per bullet to max 2 for each group • ALU performs arithmetic operations • And logical operations / comparisons • Control Unit sends / receives signals • Synchronises operations • to control operations // execution of instructions • Accept by example e.g. Input output // flow of data 4 3(b) 1 mark per bullet to max 2 for each group • Status Register is interpreted as independent bits / flags • Each flag is set depending on an event • An example: addition overflow / result of operation is zero etc. • Program Counter stores the address • of the next instruction to be fetched 4 3(c)(i) 193 1 3(c)(ii) C1 1 3(c)(iii) − 63 1 3(c)(iv) The first 4 bits / first nibble (would give 12 which) is > 9 / 2 digits (which is not valid for BCD) 1

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 5 of 9 Question Answer Marks 4(a) Parity bit 1 0 1 1 1 0 1 0 1 4(b) 1 mark for correctly circled bit Parity bit Data 0 0 1 1 0 1 0 1 1 1 1 1 1 0 0 1 1 0 1 0 1 0 0 0 0 0 0 1 1 0 1 1 Parity byte 0 1 1 1 1 1 0 1 1 4(c) 1 mark for each correct line Error detection measure 4 Proof reading Validation Type check Verification Check digit Checksum

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 6 of 9 Question Answer Marks 5(a) 1 mark per correct gate with correct inputs 3 5(b) 1 mark for each correct pair of lines A B C Working space X 0 0 0 0 0 0 1 0 0 1 0 1 0 1 1 0 1 0 0 1 1 0 1 0 1 1 0 0 1 1 1 0 4 Question Answer Marks 6(a) 1 1 6(b) 1 mark for correct method (colour code and number of pixels) 1 mark for first 7 groups correct 1 mark for remainder correct • 3B9 1A3 3B3 1A2 3B1 1A2 3B2 • 1A1 3B3 1A1 3B2 1A2 3B1 1A2 3B3 1A3 3B9 3 6(c) 5 1

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 7 of 9 Question Answer Marks 6(d) 1 mark for purpose • Stores data about the file contents/image/metadata Max 2 marks for examples of contents • Confirmation that the file is a BMP // confirmation of file type • File size • Location / offset of image data within the file • Dimensions of the image (in pixels) // image resolution • Colour depth (bits per pixel, 1, 4, 8, 16, 24 or 32) • Type of compression used (if any) 3 6(e) 1 mark for naming tool, 1 mark for describing effect on the photograph e.g. • Resize • Increase / decrease the size of the image • Crop • Remove part of the image • Blur • Reduce the focus • Red eye reduction • Reduces red (light reflected from human eyes) 6 Question Answer Marks 7(a) 1 mark per bullet to max 4 • Resistive (screen) consists of two charged plates • Pressure causes the plates to touch • Completing the circuit • Point of contact registered • Coordinates used to calculate the position • Capacitive (screen) made from materials that store electric charge • When touched charge transferred to the finger • Sensors at the (screen) corners detect the change • Point of contact registered • Coordinates used to calculate the position 4 7(b)(i) 1 mark for suitable device e.g. • Speaker • Headphones 1

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 8 of 9 Question Answer Marks 7(b)(ii) 1 mark for naming input device 1 mark for use in this scenario, for max 2 devices e.g. • Microphone • ...visitor says commands / search criteria for the computer to respond to • Keyboard • ...visitor types key words to look for • Mouse • ...visitor controls cursor to navigate / select • Trackpad • ...visitor uses finger to control cursor to navigate / select 4 7(c) 1 mark for device (Internal) hard drive / solid state drive 1 mark per bullet. Max 2 marks for each reason, max two reasons e.g. Hard drive • Large capacity... • to store videos / images / sound files with large file sizes • Reasonably fast access speed... • Users will not have to wait for videos to load • Inexpensive per unit storage... • If a large number of needed for different exhibits, the cost can be kept low • Does not need to be moved « • So moving parts unlikely to be damaged • Slower degradation of data « • So will last longer / be more reliable under heavy use Solid state • Large capacity« • To store videos/images/sound files with large file sizes • Fast access speed... • Users will not have to wait for videos to load • Reliable... • Can be dropped/damaged and will likely still work / no moving parts • Quiet... • No moving parts 5

9608/13 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 9 of 9 Question Answer Marks 7(d) 1 mark for a correct reason for RAM, 1 mark for a correct reason for ROM RAM • Currently running data / video / music / images / software ROM • Boot up instructions / OS kernel 2