Cambridge A Level Computer Science 9608 — 2018 Oct/Nov Paper 1 · Variant 1

* 8 9 3 1 1 6 5 4 3 6 * This document consists of 15 printed pages and 1 blank page. DC (ST) 144490/3 © UCLES 2018 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level COMPUTER SCIENCE 9608/11 Paper 1 Theory Fundamentals October/November 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.

2 9608/11/O/N/18 © UCLES 2018 1 A student is creating a short video and needs to record music to play in the background. (a) The student uses a microphone to capture the music. Explain how the microphone captures the music. … … … … … …[3] (b) An analogue-to-digital converter uses sampling to encode the sound. Explain how different sampling resolutions affect the sound file and the sound it represents. … … … … … …[3] (c) The student needs to edit the sound file. Describe two features of sound editing software that can be used to edit the sound file. Feature 1 … … … … Feature 2 … … … … [4]

3 9608/11/O/N/18 © UCLES 2018 [Turn over (d) The video is recorded with a frame rate of 60 frames per second (fps) and uses progressive encoding. (i) Describe what is meant by a frame rate of 60 fps. … …[1] (ii) Describe what is meant by progressive encoding in video recording. … … … …[2] (e) MP4 multimedia container format is used to save the video. State what is meant by multimedia container format. … …[1]

4 9608/11/O/N/18 © UCLES 2018 2 Computer A needs to access a web page. (a) State how Computer A could access the web page without using a Domain Name Service (DNS). … …[1] (b) (i) The following table shows four IPv6 addresses. State if each address is valid or invalid. IP address Valid or invalid 21E5:69AA:FFFF:1:E100:B691:1285:F56E ::255.255.255.255 59FB::1005:CC57:6571 56FE::2159:5BBC::6594 [4] (ii) The following table shows four statements about either public or private IP addresses. Tick (3) one box in each row to indicate whether each statement refers to a public or a private IP address. Statement Public Private 192.168.2.1 is an example of this type of address Assigned by the Internet Service Provider (ISP) IP address cannot be duplicated in different networks Network Address Translation (NAT) is necessary to access the Internet directly [4] (c) One type of transmission media is copper cable. Give two additional types of transmission media. 1 … 2 … [2]

5 9608/11/O/N/18 © UCLES 2018 [Turn over 3 Hugo has produced a program (app) for mobile phones. He needs to decide whether to use an Open Source licence or to distribute the app as shareware. (a) Describe what is meant by Open Source licence and shareware. Open Source … … … … Shareware … … … … [4] (b) Tick (3) one box to indicate the licence Hugo should use. Justify your choice. Open Source Shareware Justification … … … … …[2]

6 9608/11/O/N/18 © UCLES 2018 4 The table shows assembly language instructions for a processor which has one general purpose register, the Accumulator (ACC) and an index register (IX). Instruction Explanation Op code Operand LDD <address> Direct addressing. Load the contents of the location at the given address to ACC. LDX <address> Indexed addressing. Form the address from <address> + the contents of the Index Register. Copy the contents of this calculated address to ACC. LDR #n Immediate addressing. Load the number n to IX. STO <address> Store contents of ACC at the given address. ADD <address> Add the contents of the given address to ACC. INC <register> Add 1 to the contents of the register (ACC or IX). DEC <register> Subtract 1 from the contents of the register (ACC or IX). CMP <address> Compare contents of ACC with contents of <address>. JPE <address> Following a compare instruction, jump to <address> if the compare was True. JPN <address> Following a compare instruction, jump to <address> if the compare was False. JMP <address> Jump to the given address. OUT Output to the screen the character whose ASCII value is stored in ACC. END Return control to the operating system. (a) (i) State what is meant by direct addressing and indirect addressing. Direct addressing … … Indirect addressing … … [2] (ii) Explain how the instruction ADD 20 can be interpreted as either direct or indirect addressing. Direct addressing … … Indirect addressing … … [2]

7 9608/11/O/N/18 © UCLES 2018 [Turn over (b) The assembly language instructions in the following table use either symbolic addressing or absolute addressing. Tick (3) one box in each row to indicate whether the instruction uses symbolic or absolute addressing. Instruction Symbolic Absolute ADD 90 CMP found STO 20 [2] (c) The current contents of a general purpose register (X) are: X 1 0 1 1 1 0 1 0 (i) The contents of X represent an unsigned binary integer. Convert the value in X into denary. …[1] (ii) The contents of X represent an unsigned binary integer. Convert the value in X into hexadecimal. …[1] (iii) The contents of X represent a two’s complement binary integer. Convert the value in X into denary. …[1]

8 9608/11/O/N/18 © UCLES 2018 (d) The current contents of the main memory, Index Register (IX) and selected values from the ASCII character set are provided with a copy of the instruction set. Address Instruction 70 LDX 200 71 OUT 72 STO 203 73 LDD 204 74 INC ACC 75 STO 204 76 INC IX 77 LDX 200 78 CMP 203 79 JPN 81 80 OUT 81 LDD 204 82 CMP 205 83 JPN 74 84 END … 200 130 201 133 202 130 203 0 204 0 205 2 IX 0 ASCII code table (selected codes only) ASCII code Character 127 ? 128 ! 129 “ 130 * 131 $ 132 & 133 % 134 / Instruction Explanation Op code Operand LDD <address> Direct addressing. Load the contents of the location at the given address to ACC. LDX <address> Indexed addressing. Form the address from <address> + the contents of the Index Register. Copy the contents of this calculated address to ACC. LDR #n Immediate addressing. Load the number n to IX. STO <address> Store contents of ACC at the given address. ADD <address> Add the contents of the given address to ACC. INC <register> Add 1 to the contents of the register (ACC or IX). DEC <register> Subtract 1 from the contents of the register (ACC or IX). CMP <address> Compare contents of ACC with contents of <address>. JPE <address> Following a compare instruction, jump to <address> if the compare was True. JPN <address> Following a compare instruction, jump to <address> if the compare was False. JMP <address> Jump to the given address. OUT Output to the screen the character whose ASCII value is stored in ACC. END Return control to the operating system. Instruction set

9 9608/11/O/N/18 © UCLES 2018 [Turn over Complete the trace table for the given assembly language program. Instruction address ACC Memory address IX OUTPUT 200 201 202 203 204 205 70 130 130 133 130 0 0 2 0 [8]

10 9608/11/O/N/18 © UCLES 2018 5 For each of the following scenarios, tick (3) one box for each scenario to indicate whether you think the person’s behaviour is ethical or unethical. Justify your choice. (a) Kevin is a software engineer who has recently started a job with a new company. He is using program code from his previous employer in his new employer’s programs. Ethical Unethical Justification … … … …[2] (b) Nadya is a software developer. She has accepted a new job. She has never worked with the programming languages used by this new company. Nadya is planning to increase her knowledge of these programming languages before she starts her new job. Ethical Unethical Justification … … … …[2] (c) Maria finds that one of her team members has produced some inventive code. She presents this to her manager, stating that it was produced by the team. She does not mention the individual’s name. Ethical Unethical Justification … … … …[2]

11 9608/11/O/N/18 © UCLES 2018 [Turn over 6 A web page includes the following PHP and HTML code. 01 <?php 02 if(isset($_GET['age'])) { 03 echo "Result: ", allowed($_GET['age']); 04 } else { 05 ?> 06 07 <form action="#" method="get"> 08 Enter Age: <input type="text" name="age" /><br/> 09 <input type="submit" value="Calculate" /> 10 </form> 11 12 <?php 13 } 14 function allowed($age) { 15 if($age <= 16) $message = "You need permission"; 16 else if($age > 30) $message = "You are too old"; 17 else $message = "Allowed"; 18 return $message; 19 } 20 ?> (a) Name two identifiers used in the PHP code. 1 … 2 … [2] (b) Write the value assigned to $message if the user types 30 in the text box. …[1] (c) Explain the purpose of the code in line 18. … … … …[2]

12 9608/11/O/N/18 © UCLES 2018 (d) The PHP code in a web page uses server-side scripting. List the sequence of events that take place when a user requests a web page containing PHP code. … … … … … … … …[4]

13 9608/11/O/N/18 © UCLES 2018 [Turn over Question 7 begins on the next page.

14 9608/11/O/N/18 © UCLES 2018 7 A movie theatre has a relational database that stores the movie schedule, and information about the movies. The theatre has several screens that play movies at the same time. The database has three tables to store information about the movies, the screens and the movie schedule. MOVIE(MovieID, Title, Length, Rating) SCREEN(ScreenNumber, NumberSeats) MOVIESCHEDULE(ScheduleID, MovieID, ScreenNumber, Time) (a) Complete the entity-relationship (E-R) diagram to show the relationships between these tables. MOVIE SCREEN MOVIESCHEDULE [2] (b) Explain how primary and foreign keys are used to link the tables in the movie theatre database. … … … … … … …[4]

15 9608/11/O/N/18 © UCLES 2018 (c) The database needs to store the name of the company that produced each movie, for example, Rocking Movies. Write an SQL script to add the attribute ProductionCompany to the MOVIE table. … … … … …[2] (d) Write an SQL script to display the title and rating of all movies scheduled to play on screen number 3. … … … … … … … … … …[4]

16 9608/11/O/N/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

This document consists of 10 printed pages. © UCLES 2018 [Turn over Cambridge Assessment International Education Cambridge International Advanced Subsidiary and Advanced Level COMPUTER SCIENCE 9608/11 Paper 1 Written Paper October/November 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 October/November 2018 series for most Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 2 of 10 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.

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 3 of 10 Question Answer Marks 1(a) 1 mark per bullet point to max 3 • The microphone has a diaphragm • The incoming sound waves cause vibrations • « causing a coil to move past a magnet (dynamic microphone) // changing the capacitance (condenser microphone) • An electric current is generated / changed 3 1(b) 1 mark per bullet point • The sampling resolution number of bits used to store each sample • Increasing the (sampling) resolution means a larger file size // Decreasing the (sampling) resolution means a smaller file size • Increasing the (sampling) resolution gives a more accurate representation of the analogue sound // Decreasing the (sampling) resolution gives a less accurate representation of the analogue sound • Increasing the (sampling) resolution means a greater range of values can be stored // Decreasing the (sampling) resolution gives a smaller range of values that can be stored • Increasing the (sampling) resolution reduces the quantization errors // Decreasing the (sampling) resolution causes greater quantization errors 3 1(c) For 2 features 1 mark for identifying feature, 1 mark for describing what it does. For example: • Cut/delete • ... Remove part of the sound file • Copy and paste • ... Replicate part of the sound • Amplify • ... Increase the volume of a section of sound 4 1(d)(i) 60 images are recorded per second 1 1(d)(ii) 1 mark per bullet point to max 2 • Each frame contains (all the lines for) the complete image • All the frame data is recorded at the same time • Each frame contains all the scan lines • The number of images stored is the same as the frame rate 2 1(e) 1 mark per bullet point to max 1 • A meta file / wrapper • Contains various different types of data 1

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 4 of 10 Question Answer Marks 2(a) Use the IP address instead of the URL 1 2(b)(i) 1 mark per correct answer IP Address Valid or invalid 21E5:69AA:FFFF:1:E100:B691:1285:F56E Valid ::255.255.255.255 Valid 59FB::1005:CC57:6571 Valid 56FE::2159:5BBC::6594 Invalid 4 2(b)(ii) 1 mark per correct row Statement Public Private 192.168.2.1 is an example of this type of address 3 Assigned by the Internet Service Provider (ISP) 3 IP address cannot be duplicated in different networks 3 Network Address Translation (NAT) is necessary to access the Internet directly 3 4 2(c) 1 mark per example to max 2 • Fibre-optic • Wi-Fi / Radio waves • Microwave • Infrared 2

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 5 of 10 Question Answer Marks 3(a) 1 mark per bullet point, max 2 marks per licence Open Source • The source code is released with program • Users can edit the source code to suit their needs • Users re-release their version under the same terms • Can be cost-free but may also need payment Shareware • Users get a free trial of the software • « which may be limited in features • No access to source code // Program cannot be edited • Then they have to pay / sign-up after the expiry date // Then they have to pay / sign-up to get full functionality // Then they have to pay / sign-up to stop unwanted pop-ups, etc. 4 3(b) 1 mark per bullet point to max 2 marks for chosen licence Open Source For example: • Hugo does not have to set up ways to take funds • Others may enhance / improve the program • Hugo can charge a fee for the App Or Shareware For example: • Hugo can charge for the App • Not giving away the code/people can't copy the code • « Hugo gets the sole recognition for the program • Possible legal consequences if someone does copy the code • If users need to sign up, their data can be used for marketing etc. • Customers have peace of mind that the software hasn’t been maliciously edited / bugs introduced 2 Question Answer Marks 4(a)(i) 1 mark for each type of addressing Direct addressing • The operand is the address where the data is stored Indirect addressing • The operand is an address, that address holds another address where the data is stored 2

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 6 of 10 Question Answer Marks 4(a)(ii) 1 mark per bullet point Direct addressing: • 20 is the address of the data Indirect addressing: • 20 is an address which holds the address where the data is stored 2 4(b) 1 mark for 1 correct tick 2 marks for 3 correct ticks Instruction Symbolic Absolute ADD 90 9 CMP found 9 STO 20 9 2 4(c)(i) 186 1 4(c)(ii) BA 1 4(c)(iii) –70 1 4(d) 1 mark per bullet point • Outputting * (instruction 71) • Storing 130 in 203 (instruction 72) • Loading, incrementing accumulator and storing in 204 (instructions 73, 74 and 75) • Incrementing Index Register (instruction 76) • Loading 133, comparing and jumping to 81 (instructions 77, 78 and 79) • Loading, comparing and jumping to 74 (instructions 81, 82 and 83) • Incrementing accumulator, storing in 204 and incrementing index register, loading 130 (instructions 74–79) • Outputting * to end (instructions 80–84) 8

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 7 of 10 Instruction address ACC Memory address IX (Index Register) OUTPUT 200 201 202 203 204 205 70 130 130 133 130 0 0 2 0 71 * 72 130 73 0 74 1 75 1 76 1 77 133 78 79 81 1 82 83 74 2 75 2 76 2 77 130 78 79 80 * 81 2 82 83 84

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 8 of 10 Question Answer Marks 5(a) 1 mark per bullet point for each justification, to max 2 Either Unethical • Work belongs to the company it was created for // copyright • « Kevin cannot use it without permission • It reduces the integrity of the person / profession / new company • Reference to IEEE standards in context Or Ethical • The program code could be open source • Kevin might own the copyright of code • Kevin may have permission to use the code • Reference to IEEE standards in context 2 5(b) 1 mark per bullet point for each justification, to max 2 Either Unethical • Nadya has accepted a role / work she knows she cannot do • This reduces the integrity of the person • She may let down the new organisation who are expecting her to be able to do the work • Reference to IEEE standards in context Or Ethical • She is taking steps to prepare for the role • « Without expecting the company to do it • Nadya may have told the company that she didn’t know the languages but that she would learn them • Reference to IEEE standards in context 2 5(c) 1 mark per bullet point for each justification, to max 2 Either Ethical • The individual works as part of the team « • « therefore, the team should / will get the credit • Maria is not lying about who produced it • Reference to IEEE standards in context Or Unethical • Maria should identify who / where the idea originated • It prevents the individual getting recognition • Maria is not being supportive of the individual • Reference to IEEE standards in context 2

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 9 of 10 Question Answer Marks 6(a) 1 mark per bullet point to max 2 • $age • $message • allowed 2 6(b) Allowed 1 6(c) 1 mark per bullet point • Passes the value in $message / message variable « • « back to the code that called it // « to replace the function call 2 6(d) 1 mark per bullet point to max 4 • The (client web) browser requests the web page from the web server • The web server accesses the page (from its hard drive) • The web server processes / executes the PHP code « • « and produces the HTML for the web page // « the web server creates the web page • The web server returns the (HTML) web page to the client web browser 4 Question Answer Marks 7(a) 1 mark for each correct join 2 7(b) 1 mark per bullet point • MovieID is the Primary Key in MOVIE • « links to MovieID which is the Foreign Key in MOVIESCHEDULE • ScreenNumber is the Primary Key in SCREEN • « links to ScreenNumber which is the Foreign Key in MOVIESCHEDULE 4 7(c) 1 mark per bullet point • ALTER TABLE MOVIE • ADD (COLUMN)ProductionCompany VARCHAR(25); 2 MOVIE SCREEN MOVIESCHEDULE

9608/11 Cambridge International AS/A Level – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 10 of 10 Question Answer Marks 7(d) 1 mark per bullet point Answer 1: • SELECT Title, Rating • FROM MOVIE, MOVIESCHEDULE • WHERE MOVIE.MovieID = MOVIESCHEDULE.MovieID • AND MOVIESCHEDULE.ScreenNumber = 3; Or Answer 2: • SELECT Title, Rating • FROM MOVIE INNER JOIN MOVIESCHEDULE • ON MOVIE.MovieID = MOVIESCHEDULE.MovieID • WHERE MOVIESCHEDULE.ScreenNumber = 3; 4