Cambridge A Level Computer Science 9608 — 2021 May/June Paper 1 · Variant 1

This document has 20 pages. Any blank pages are indicated. Cambridge International AS & A Level COMPUTER SCIENCE 9608/11 Paper 1 Theory Fundamentals May/June 2021 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. * 7 0 0 0 4 4 5 1 9 6 * DC (LK/CGW) 205103/2 © UCLES 2021 [Turn over

2 9608/11/M/J/21 © UCLES 2021 1 Draw one line from each software licence to its correct description. Software licence Description A limited version of the software could be released and downloaded by anyone, but users would need to pay to unlock additional features. Shareware A licence must be purchased to use the software. Open Source Users cannot download the software over the Internet. Commercial The original source code is made available for other developers who can then modify and improve the software. [3]

3 9608/11/M/J/21 © UCLES 2021 [Turn over 2 Zak designs a logo for his company. He uses vector graphics software to create the logo. (a) One of the drawing objects in the logo is a circle. Identify four properties of the circle. 1 … 2 … 3 … 4 … [4] (b) Describe what is meant by a drawing list using the logo as an example. … … … … [2]

4 9608/11/M/J/21 © UCLES 2021 (c) Zak could have used a bitmapped image for the logo. Describe two drawbacks of using a bitmapped image for the logo instead of a vector graphic. Drawback 1 … … … … Drawback 2 … … … … [4] (d) Zak’s company holds details about clients in a database. Give three security measures that Zak can implement to make sure that only authorised employees can access the data. 1 … 2 … 3 … [3]

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6 9608/11/M/J/21 © UCLES 2021 3 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 LDD <address> Direct addressing. Load the content of the location at the given address to ACC. LDI <address> Indirect addressing. The address to be used is at the given address. Load the contents of this second address to ACC. DEC <register> Subtract 1 from the contents of the register (ACC or IX). CMP <address> Compare the contents of ACC with the contents of <address>. JMP <address> Jump to the given address. JPE <address> Following a compare instruction, jump to <address> if the compare was True. STO <address> Store the contents of ACC at the given address. END Return control to the operating system. The current contents of the main memory are: Address Instruction 100 LDD 200 101 CMP 201 102 JPE 106 103 DEC ACC 104 STO 200 105 JMP 101 106 END … 200 2 201 0 202 200

7 9608/11/M/J/21 © UCLES 2021 [Turn over (a) Trace the program currently in memory using the following trace table. Instruction address ACC Memory address 200 201 202 2 0 200 [3] (b) The instruction in memory address 100 needs to be changed. It needs to use indirect addressing to load the contents of memory address 200. Give the new instruction to replace LDD 200. … [1]

8 9608/11/M/J/21 © UCLES 2021 (c) Each instruction in the assembly language program is encoded in 16 bits (8-bit op code followed by an 8-bit operand). (i) The instruction CMP 201 has the operand 201. Convert the operand 201 into 8-bit binary. [1] (ii) State the maximum number of op codes that can be represented using eight bits. … [1] (d) The status register contains condition flags. Identify three condition flags that can be set in the status register. 1 … 2 … 3 … [3]

9 9608/11/M/J/21 © UCLES 2021 [Turn over 4 Consider the following logic circuit: A B C X (a) Complete the truth table for the logic circuit. 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] (b) Identify three logic gates not used in the logic circuit. Gate 1 … Gate 2 … Gate 3 … [1]

10 9608/11/M/J/21 © UCLES 2021 5 A company runs activity courses. It is creating a relational database to store details of the courses it runs. The database has five tables: EMPLOYEE(EmployeeID, FirstName, LastName, Role, Language) BOOKING(BookingID, CustomerID, CourseID) CUSTOMER(CustomerID, FirstName, LastName) COURSE(CourseID, Title, Level, Date) COURSE_EMPLOYEE(CourseID, EmployeeID) (a) Complete the entity relationship (E-R) diagram for the database. COURSE BOOKING CUSTOMER COURSE_EMPLOYEE EMPLOYEE [4] (b) Describe what is meant by referential integrity. Give an example from the CUSTOMER and BOOKING tables in your answer. … … … … [2]

11 9608/11/M/J/21 © UCLES 2021 [Turn over (c) A Data Definition Language (DDL) is used to create the structure of the database. One item that can be created is the database. Identify three other items that can be created in the database using the DDL. 1 … 2 … 3 … [3] (d) Part of the EMPLOYEE table is shown. EmployeeID FirstName LastName Role Language 001 Jasmine Chen Leader French 002 Kenton Archer Leader English 003 Michael Roux Cook French 004 Conrad Slavorski Leader Russian Write a Data Manipulation Language (DML) statement to return the first name and last name of all employees, who are leaders, and speak either French or English. … … … … … … [4]

12 9608/11/M/J/21 © UCLES 2021 6 A web page includes HTML, JavaScript and PHP code. 01 <html> 02 <body> 03 04 <p> 05 <?PHP 06 $message = "Enter the current time" 07 echo $message 08 ?> 09 </p> 10 11 24 hour clock hour<input id = "Time" value = ""> 12 <button onclick = "timeOfDay()">Enter</button> 13 14 <script> 15 function timeOfDay() { 16 var hour, greeting; 17 hour = document.getElementById("Time").value; 18 if (hour < 18) { 19 greeting = "Good day"; 20 } else { 21 greeting = "Good evening"; 22 } 23 alert(greeting); 24 } 25 </script> 26 27 </body> 28 </html> (a) The page is loaded and the value 16 is entered. State the output when the enter button is clicked. … [1] (b) Give the line number where the JavaScript function is called. … [1] (c) Give the identifier names of two variables used in the JavaScript code. 1 … 2 … [1]

13 9608/11/M/J/21 © UCLES 2021 [Turn over (d) Tick (3) one box in each row to indicate whether each of the following statements is true or false. Statement True False The program contains client-side and server-side code The PHP code in the program will run on the client-side Line 19 of the code outputs the message "Good day" Line 18 of the code contains a conditional statement [2] (e) Examine the following list of terms: bandwidth browser compiler HTML interpreter JavaScript PHP router server server-side transmission validation Complete the following sentences by filling in the missing terms from the list. Some terms may be used more than once. Some terms are not used. … can be performed both client-side and server-side. It is performed more rapidly by the … because there is no delay in transmitting and receiving data to and from the … . It is also performed on the server-side, because the client’s … may not support … , so the data will still need checking to avoid errors. [5]

14 9608/11/M/J/21 © UCLES 2021 7 This question presents three scenarios. Tick (3) one box for each scenario to indicate whether you think the behaviour shown is ethical or unethical. Justify your choice. (a) Marina has a very short deadline to create a piece of software for a client. Algorithm A is quick to code and simpler to test but has an inefficient run time. Algorithm B is more complex to code and test but has a more efficient run time. She decides to implement algorithm A. Ethical Unethical Justification … … … … … [2] (b) Doug is managing a project for a client that has fallen behind schedule. He asks all members of the project team to work extra hours and to cancel any holiday plans to get the project back on schedule. Ethical Unethical Justification … … … … … [2]

15 9608/11/M/J/21 © UCLES 2021 [Turn over (c) Debbie is programming a car safety management system. She thinks that the test plan she has been given is not adequate. She decides to discuss her concerns on a public internet forum. Ethical Unethical Justification … … … … … [2]

16 9608/11/M/J/21 © UCLES 2021 8 Jay is developing a computer game that allows users to create stories. (a) Jay uses a language translator to develop the computer game. (i) Tick (3) one or more boxes in each row to identify the language translator(s) each statement describes. Statement Assembler Interpreter Compiler Translates and executes each line of source code one line at a time Translates low-level source code into machine code Must be present in memory to execute the code Translates high-level source code into low-level code [4] (ii) Jay decides to use a compiler to develop the game. Identify two benefits of using a compiler. Benefit 1 … … Benefit 2 … … [2]

17 9608/11/M/J/21 © UCLES 2021 [Turn over (b) The game generates a story which is stored as a text file. Jay compresses the text file using lossless compression before sending it by email to his friend. (i) Identify two reasons for compressing the text file. 1 … … 2 … … [2] (ii) Explain the reasons why Jay compresses the text file with lossless compression instead of lossy compression. … … … … [2]

18 9608/11/M/J/21 © UCLES 2021 9 (a) Identify two differences between a public IP address and a private IP address. 1 … … 2 … … [2] (b) Complete the table by identifying the most appropriate term for each description. Each term must be different. Description Term Receives data packets from a network and forwards them onto a similar network Manages access to a centralised resource Joins networks that use different sets of rules to transmit data Monitors and controls incoming and outgoing network traffic based on set criteria [4]

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20 9608/11/M/J/21 © UCLES 2021 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. BLANK PAGE

This document consists of 10 printed pages. © UCLES 2021 [Turn over Cambridge International AS & A Level COMPUTER SCIENCE 9608/11 Paper 1 Theory Fundamentals May/June 2021 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 2021 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 May/June 2021 © UCLES 2021 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 May/June 2021 © UCLES 2021 Page 3 of 10 Question Answer Marks 1 1 mark for each licence correctly identified 3 Question Answer Marks 2(a) 1 mark per bullet point to max 4 • The position/coordinate of the centre of the circle • Radius • Line width • Line colour • Line style • Fill colour 4 2(b) 1 mark per bullet point • A list that stores each separate object in the logo // a list that stores the command/description required to draw each object • Each shape has its own drawing list • Example related to logo, e.g. Three triangles, one square and one circle 2 2(c) 1 mark per drawback, 1 mark for expansion (max 2 each) • A bitmap file is likely to take up more storage space • …because the colour of each pixel needs to be stored • A bitmap image cannot be enlarged // difficult to use in different types of document • …without the image pixelating • A bitmap would be more difficult to edit • …because each pixel would need to be edited separately 4

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 4 of 10 Question Answer Marks 2(d) 1 mark per bullet point to max 3 • Password • Biometrics • Access rights • Swipe cards • Physical access measures, e.g. security guards • Implement a firewall/proxy to monitor remote access requests • Two-step authentication 3 Question Answer Marks 3(a) 1 mark for each set of shaded rows Instruction Address ACC Memory Address 200 201 202 2 0 200 100 2 101 102 103 1 104 1 105 101 102 103 0 104 0 105 101 102 106 3 3(b) LDI 202 1 3(c)(i) 1100 1001 1 3(c)(ii) 256 1

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 5 of 10 Question Answer Marks 3(d) 1 mark per bullet point to max 3 e.g. • Zero • Carry • Overflow • Sign/negative • Compare results • Parity 3 Question Answer Marks 4(a) 1 mark per pair of outputs (shaded) A B C Working space X 0 0 0 0 0 0 1 1 0 1 0 0 0 1 1 0 1 0 0 0 1 0 1 1 1 1 0 0 1 1 1 0 4 4(b) 1 mark for all three gates: OR XOR NOT 1

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 6 of 10 Question Answer Marks 5(a) 1 mark for each link: • 1 CUSTOMER to many BOOKING • 1 COURSE to many BOOKING • 1 COURSE to many COURSE_EMPLOYEE • 1 EMPLOYEE to many COURSE_EMPLOYEE 4 5(b) 1 mark for description and 1 mark for application to the given tables e.g. (2 marks) • each value stored in the CustomerID (FK) field in the Booking table must have a corresponding value (1) in the CustomerID (PK) field in the Customer table (1) e.g. (1 mark) • Each foreign key value must have a matching value in the primary key of the linked table (1) 2 5(c) 1 mark each (max 3) e.g. • Tables • Fields/attributes • Indexes • Users • Primary Key • Foreign Key • Relationships • Views 3

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 7 of 10 Question Answer Marks 5(d) 1 mark per syntactically correct bullet point: • Select correct fields • From correct table • Correct criteria for Role • Correct criteria for Language Example: SELECT FirstName, LastName FROM EMPLOYEE WHERE Role = "Leader" AND (Language = "French" OR Language = "English"); 4 Question Answer Marks 6(a) Good day 1 6(b) 12 1 6(c) 1 mark for both answers hour greeting 1 6(d) 1 mark for each pair of correct answers (shaded): Statement True False The program contains client-side and server-side code  The PHP code in the program will run on the client-side  Line 19 of the code outputs the message "Good day"  Line 18 of the code contains a conditional statement  2 6(e) 1 mark for each correctly completed term Validation can be performed both client-side and server-side. It is performed more rapidly by the browser because there is no delay in transmitting and receiving data, to and from the server. It is also performed server-side because the client's browser may not support JavaScript, so the data will still need checking to avoid errors. 5

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 8 of 10 Question Answer Marks 7(a) 1 mark per bullet point for each justification, to max 2 Either Unethical • Marina knowingly produces a solution that is not as efficient as it could be • …and this does not enhance the reputation of the person/company • Reference to IEEE standards in context Or Ethical • Marina acts in the best interests of the employer to complete a working product on time • …that is more likely to be correct as the coding is simpler • Reference to IEEE standards in context 2 7(b) 1 mark per bullet point for each justification, to max 2 Either Unethical • Doug has a management responsibility • …to be fair to his colleagues • …but is showing a lack of personal integrity by applying pressure • Reference to IEEE standards in context Or Ethical • Doug is trying to act in the best interests of his employer/client • …and may be asking employees to voluntarily offer to work additional hours • …he may be paying them extra • Reference to IEEE standards in context 2 7(c) 1 mark per bullet point for each justification, to max 2 Either Unethical • Debbie may be breaking company policy discussing current projects // confidentiality • …and has a duty to act in the best interests of his company • …and should have raised her concerns internally • Reference to IEEE standards in context Or Ethical • Debbie may feel that in the public interest the problem should be discussed • …to ensure that a safety critical system is fully tested • …so as to prevent potential loss of life • Reference to IEEE standards in context 2

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 9 of 10 Question Answer Marks 8(a)(i) 1 mark per correct row Statement Assembler Interpreter Compiler Translates and executes each line of source code one line at a time  Translates low-level source code into machine code  Must be present in memory to execute the code  Translates high-level source code into low-level code   4 8(a)(ii) 1 Mark per bullet point to max 2 • The compiler is not required to run the program • The program can be distributed without the source code • A compiler produces code that executes faster than the equivalent for an interpreter 2 8(b)(i) 1 mark per bullet point to max 2 • To reduce the storage space required to store the file • To reduce the time it would take to transmit the file • Because they have to email it and have limited file sizes for sending/receiving 2 8(b)(ii) 1 mark per bullet point • All of the original data needs to be retained/recoverable • … because otherwise the file contents would not make sense 2 Question Answer Marks 9(a) 1 mark per difference • Private IP is only known within the LAN // Public IP is known outside of the LAN/ on Internet • Public is allocated by ISP // Private is allocated by the router • Public addresses are unique throughout the Internet, private addresses are unique only within the LAN • Private IP addresses are more secure than public IP addresses 2

9608/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 10 of 10 Question Answer Marks 9(b) 1 mark for each correct term Description Term Receives data packets from a network and forwards them onto a similar network Router Manages access to a centralised resource Server Joins networks that use different sets of rules to transmit data Gateway Monitors and controls incoming and outgoing network traffic based on set criteria Firewall 4