Cambridge A Level Computer Science 9608 — 2020 May/June Paper 1 · Variant 2

This document has 16 pages. Blank pages are indicated. DC (RW/FC) 183148/3 © UCLES 2020 [Turn over * 8 9 6 4 5 1 8 2 1 7 * COMPUTER SCIENCE 9608/12 Paper 1 Theory Fundamentals May/June 2020 1 hour 30 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use an HB pencil for any diagrams, graphs or rough working. ● Calculators must not be used in this paper. INFORMATION ● The total mark for this paper is 75. ● The number of marks for each question or part question is shown in brackets [ ]. ● No marks will be awarded for using brand names of software packages or hardware. Cambridge International AS & A Level

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3 9608/12/M/J/20 © UCLES 2020 [Turn over 1 Samira is creating an interactive, multimedia presentation for the entrance to her hotel. (a) The presentation will be on a device that has a resistive touchscreen for user input. Complete the following paragraph about the basic operation of a resistive touchscreen. The resistive touchscreen has two layers with … between the layers. When a finger touches the screen, the … moves to touch the … ; this creates a point of contact. The … and … position of this point is calculated. [4] (b) Samira uses a computer to draw a logo for her hotel and saves it as a vector graphic. The logo will be placed on the multimedia presentation and elsewhere, such as on signs at the entrance of the hotel. Samira emails the logo to a company that prints signs, and other documentation for the hotel. (i) Describe how the logo is represented by the computer. … … … … … … … … [3] (ii) State two reasons why the hotel logo is saved as a vector graphic instead of a bitmapped graphic. 1 … … 2 … … [2]

4 9608/12/M/J/20 © UCLES 2020 2 Amir has created a sound file using his desktop computer. (a) Complete the table by writing the missing definitions and term about sound. Term Definition Sampling … … … … … … The number of samples per unit time Sampling resolution … … … … [3] (b) The file is too large to be emailed and the file size needs to be reduced. (i) Name one lossless compression technique that can be used to reduce the size of the sound file. … … [1] (ii) Describe one lossy compression technique that can be used to reduce the size of the sound file. … … … … [2]

5 9608/12/M/J/20 © UCLES 2020 [Turn over (c) Amir’s computer has system software, including utility software and an operating system. (i) Explain how the disk formatter, disk contents analysis and disk repair utilities work together. … … … … … … [3] (ii) Amir’s computer has several peripheral devices connected to it. State three peripheral management tasks performed by the operating system. Task 1 … … Task 2 … … Task 3 … … [3] (iii) The peripheral devices are plugged into USB ports of the computer. Describe two benefits of connecting the peripheral devices using a USB port. 1 … … … … 2 … … … … [4]

6 9608/12/M/J/20 © UCLES 2020 3 The following is a logic expression. X = NOT (A AND B) OR NOT (NOT B OR C) Draw the logic circuit for the given expression using a maximum of four gates. X B A C [4]

7 9608/12/M/J/20 © UCLES 2020 [Turn over 4 Sophie is about to start a new job as a junior software developer. (a) She is worried about joining a new team of people. (i) State one ethical action that Sophie can take to help her to feel more confident about starting work. … … [1] (ii) State two ethical actions that Sophie’s manager can take to help Sophie to feel more confident about starting work. 1 … … 2 … … [2] (iii) State one ethical action that Sophie’s new colleagues can take to help Sophie to feel more confident about starting work. … … [1] (b) Explain why Sophie is asked to sign a professional code of conduct before starting work. … … … … … … [3]

8 9608/12/M/J/20 © UCLES 2020 5 (a) The steps 1 to 6 describe the first pass of a two‑pass assembler. The following three statements are used to complete the sequence of steps. A If it is already in the symbol table, it checks to see if the absolute address is known B When it meets a symbolic address, it checks to see if it is already in the symbol table C If it is known, it is entered Write one of the letters A, B or C in the appropriate step to complete the sequence. 1. The assembler reads the assembly language instructions 2. … 3. If it is not, it adds it to the symbol table 4. … 5. … 6. If it is not known, it is marked as unknown. [2]

9 9608/12/M/J/20 © UCLES 2020 [Turn over (b) The assembler translates assembly code into machine code. The table shows the denary values for three assembler op codes. Op code Denary value LDD 194 ADD 200 STO 205 (i) Convert the denary value for the op code LDD into 8‑bit binary. [1] (ii) Convert the denary value for the op code STO into hexadecimal. … [1] (iii) State why the denary value for the op code ADD cannot be represented in 8‑bit two’s complement form. Justify your answer. … … … … [2]

10 9608/12/M/J/20 © UCLES 2020 (c) The table shows part of the instruction set for a processor. The processor has one general purpose register, the Accumulator (ACC), and an Index Register (IX). Instruction Explanation Op code Operand LDM #n Immediate addressing. Load the denary number n to ACC 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 denary 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) CMP <address> Compare contents of the address given with the contents of ACC 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 screen the character whose ASCII value is stored in ACC END Return control to the operating system

11 9608/12/M/J/20 © UCLES 2020 [Turn over Complete the trace table for the following assembly language program. The first instruction has been completed for you. Address Instruction 20 LDD 103 21 CMP 101 22 JPE 30 23 LDD 100 24 ADD 101 25 STO 100 26 LDD 103 27 INC ACC 28 STO 103 29 JMP 20 30 END … 100 1 101 2 102 3 103 0 Instruction address ACC Memory address 100 101 102 103 1 2 3 0 20 0 [6]

12 9608/12/M/J/20 © UCLES 2020 6 A software development company has a relational database, SOFTWARE_MANAGEMENT. The database stores details of the customers who have purchased software, as well as the software and licences that customers have purchased. The SOFTWARE_MANAGEMENT database has the following tables: CUSTOMER_DETAILS(CustomerID, CompanyName, Address1, Address2, City) SOFTWARE_PURCHASED( SoftwareName, SoftwareDescription, CustomerID, LicenceType, LicenceCost, RenewalDate) (a) Explain why this database is not in Third Normal Form (3NF). Refer to the tables in your answer. Do not attempt to normalise the tables. … … … … … … [2] (b) Give an example from the database SOFTWARE_MANAGEMENT for each of the following database terms. Term Example Entity Foreign key Attribute [3]

13 9608/12/M/J/20 © UCLES 2020 [Turn over (c) The company also develops computer games. They extend the relational database SOFTWARE_MANAGEMENT by adding a new table. The new table, GAME_DEVELOPMENT, stores details about the games and the software development teams creating them. The table shows example data in GAME_DEVELOPMENT. GameName Genre TeamNumber DevelopmentStage ManagerID Bunny Hop Platform 4 Analysis 23KP Fried Eggs Retro 2 Programming stage 1 9RTU Create‑a‑game Action 1 Acceptance testing 11TF (i) Complete the Data Definition Language (DDL) statement to create the table GAME_DEVELOPMENT. CREATE ………………………………………………………… ………………………………………………………… ( GameName VarChar, Genre VarChar, ………………………………………………………… ………………………………………………………… , DevelopmentStage VarChar, ManagerID VarChar, ………………………………………………………… (GameName) ); [5] (ii) Another table, PRODUCT_MANAGER, is created. PRODUCT_MANAGER(ManagerID, FirstName, LastName) Complete the Data Manipulation Language (DML) statement to return the game name, genre and team number of all games managed by the product manager with the first name ‘James’ and the last name ‘Fitz’. ………………………………………………………… GameName, Genre, TeamNumber FROM GAME_DEVELOPMENT, PRODUCT_MANAGER WHERE PRODUCT_MANAGER.FirstName = "James" AND PRODUCT_MANAGER.LastName = "Fitz" AND ………………………………………………………………………………………………… = …………………………………………………………………………………………………… ; [3]

14 9608/12/M/J/20 © UCLES 2020 7 A company allows customers to stream music from its servers over the Internet. The company’s internet connection is currently provided through copper cables. (a) Identify two pieces of hardware, other than the cables, that enable the servers to connect to the Internet. Describe the purpose of each device. Device 1 … Purpose … … … Device 2 … Purpose … … … [4] (b) The company wants to upgrade their internet connection to fibre‑optic cables. Give one benefit and one drawback to the company of upgrading to fibre‑optic cables. Benefit … … … Drawback … … … [2]

15 9608/12/M/J/20 © UCLES 2020 [Turn over (c) A customer enters a song title into a web page to listen to the song. The design of the web page is shown: Company Name Navigation Bar Enter song title: Search The web page will make use of both client‑side and server‑side scripting. (i) Explain how client‑side scripting will be used in this web page. … … … … … … [3] (ii) Explain how server‑side scripting will be used after the customer clicks the ‘Search’ button. … … … … [2]

16 9608/12/M/J/20 © UCLES 2020 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 Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge. (d) The company needs to keep the data on its servers secure from online threats. (i) Describe how a firewall will help to protect the data on the servers from online threats. … … … … [2] (ii) Give one additional security measure that the company can use to protect the data on the servers from online threats. … [1]

This document consists of 9 printed pages. © UCLES 2020 [Turn over Cambridge International AS & A Level COMPUTER SCIENCE 9608/12 Paper 1 Written Paper May/June 2020 MARK SCHEME Maximum Mark: 75 Published Students did not sit exam papers in the June 2020 series due to the Covid-19 global pandemic. This mark scheme is published to support teachers and students and should be read together with the question paper. It shows the requirements of the exam. The answer column of the mark scheme shows the proposed basis on which Examiners would award marks for this exam. Where appropriate, this column also provides the most likely acceptable alternative responses expected from students. Examiners usually review the mark scheme after they have seen student responses and update the mark scheme if appropriate. In the June series, Examiners were unable to consider the acceptability of alternative responses, as there were no student responses to consider. Mark schemes should usually be read together with the Principal Examiner Report for Teachers. However, because students did not sit exam papers, there is no Principal Examiner Report for Teachers for the June 2020 series. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the June 2020 series for most Cambridge IGCSE™ and Cambridge International A & AS Level components, and some Cambridge O Level components.

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 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.

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 3 of 9 Question Answer Marks 1(a) 1 mark for each correct term The resistive touchscreen has two layers with a gap / an air gap between the layers. When a finger touches the screen, the top layer moves to touch the bottom layer; this creates a point of contact. The horizontal and vertical position of this point is calculated. 4 1(b)(i) 1 mark per bullet point to max 3 • It is a series of (geometric) shapes / lines / objects • Stored coordinates • Contains a drawing list • Commands / formulae for creating each individual object • and the attributes/property for that object • E.g. the colour, thickness of line etc. 3 1(b)(ii) 1 mark per bullet point to max 2 • Needs to be large for the signs without becoming pixelated. • Smaller file size means faster transfer rates are possible. • Smaller file size reduces storage requirements when stored many times (on multiple documents). 2 Question Answer Marks 2(a) 1 mark for each correct term/definition Term Definition Sampling The amplitude of the analogue sound wave is recorded at regular/set intervals Sampling rate The number of samples per unit time Sampling resolution The number of bits used to store each sample 3 2(b)(i) 1 mark only from: • Run-length encoding • Huffman Coding • Any other valid encoding method 1 2(b)(ii) 1 mark per bullet point to max 2 • Reduce sampling rate • ... fewer samples taken per second means less data is being stored Or • Reduce sample resolution • ... fewer bits are used to represent each sample, so less data is stored 2

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 4 of 9 Question Answer Marks 2(c)(i) 1 mark per bullet point to max 3 • Disk contents analysis checks for errors/problems with the disk • Disk repair attempts to fix the errors • The disk formatter prepares the disk for (initial) use (again). 3 2(c)(ii) 1 mark per bullet point to max 3 • Installation of device driver software • Managing interrupts / signals from the device • Sending control signals to the device • Control of buffers • Management of queues 3 2(c)(iii) 1 mark for benefit, 1 mark for expansion for max 2 benefits • Fast data transfer • … useful when transferring large files such as video files • Automatic connection / plug-and-play • … so usually there is no need to install separate device drivers • USB is a standard adopted by many manufacturers • … meaning all new computers will be equipped with USB ports • Devices may be powered or charged through USB • … so external devices may be charged while working at the computer 4 Question Answer Marks 3 1 mark for each correct gate X = NOT (A AND B) OR NOT (NOT B OR C) 4 4(a)(i) 1 mark only e.g. • Read about the languages she will be using • Visits the office prior to starting • Speaks to her manager about concerns 1

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 5 of 9 Question Answer Marks 4(a)(ii) 1 mark per action to max 2 For example: • Prepare an induction • Invite Sophie in before starting • Introduce Sophie to the team • Give Sophie a mentor 2 4(a)(iii) 1 mark only e.g. • Prepare a greeting/introduction • Provide structured support • Invite Sophie to social event(s) before/at the start to meet people 1 4(b) 1 mark per bullet point to max 3 • Sophie is confirming that she understands the code of conduct • To make sure Sophie knows what behaviour is expected of her • To make sure Sophie understands there may be consequences of some actions • To ensure all employees adhere to the same standards 3 Question Answer Marks 5(a) 1 mark for one letter in the correct place, 2 marks for all three correct 2 B 4 A 5 C 2 5(b)(i) 11000010 1 5(b)(ii) CD 1 5(b)(iii) 1 mark per bullet point to max 2 • The maximum range for an 8-bit two's complement binary number is −128 to +127 • … 200 is outside of the maximum range 2

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 6 of 9 Question Answer Marks 5(c) 1 mark for each highlighted section block Instruction address ACC Memory address 100 101 102 103 1 2 3 0 20 0 21 22 23 1 24 3 25 3 26 0 27 1 28 1 29 20 1 21 22 23 3 24 5 25 5 26 1 27 2 28 2 29 20 2 21 22 30 6

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 7 of 9 Question Answer Marks 6(a) 1 mark per bullet point to max 2 • There are partial dependencies in the SOFTWARE_PURCHASED table // SoftwareDescription is dependent only on SoftwareName and not both SoftwareName and CustomerID • There is a non-key dependency in the SOFTWARE_PURCHASED table // LicenceCost is dependent on LicenceType 2 6(b) 1 mark for a suitable example for each Term Example Entity SOFTWARE_PURCHASED //CUSTOMER_DETAILS Foreign Key CustomerID (in SOFTWARE_PURCHASED table) Attribute Any valid example of an attribute from the tables 3 6(c)(i) 1 mark for each correct entry (in bold) CREATE TABLE GAME_DEVELOPMENT ( GameName VarChar, Genre VarChar, TeamNumber Integer, DevelopmentStage VarChar, ManagerID VarChar, PRIMARY KEY (GameName) ); 5 6(c)(ii) 1 mark for each correct entry (shown in brackets) SELECT (1) GameName, Genre, TeamNumber FROM GAME_DEVELOPMENT, PRODUCT_MANAGER WHERE PRODUCT_MANAGER.FirstName = "James" AND PRODUCT_MANAGER.SecondName = "Fitz" AND PRODUCT_MANAGER.ManagerID (1) = GAME_DEVELOPMENT.ManagerID (1) ; 3

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 8 of 9 Question Answer Marks 7(a) 1 mark for device, 1 mark for matching purpose. Max 2 devices. • Router • To connect (devices) / the servers to the Internet // to transmit data between the servers and the Internet // to forward data towards its destination • Gateway • To connect a server that uses a different protocol to the Internet // to join two different types of network • Modem • To connect (the servers) to the Internet over a telephone line • Network interface card // NIC • To enable the servers to connect to the (company) network 4 7(b) 1 mark per bullet point, max 1 for benefit, max 1 for drawback Benefit: • (Consistently) faster data transmission • More stable connection Drawback: • High initial cost as new hardware will be needed • Expertise required to complete connections 2 7(c)(i) 1 mark per bullet point to max 3 • The web page may have interactive features • Created using JavaScript • E.g. text box, buttons • Validates the input client-side • Handles the data returned from the server-side script 3 7(c)(ii) 1 mark per bullet point to max 3 • Database on the server is accessed • Using PHP • Searches for the data the user entered • Returns the song // Returns a message to say song not found 2 7(d)(i) 1 mark per bullet point to max 2 • Prevents unauthorised access to the data • Monitors incoming and outgoing traffic • Blocks transmissions from unauthorised sources / websites / ports • Maintains an allow list / deny list of IP addresses 2

9608/12 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2020 © UCLES 2020 Page 9 of 9 Question Answer Marks 7(d)(ii) 1 mark only from: • Running up-to-date antivirus software • Use of proxy server • Strong / Biometric passwords • Etc. 1