Cambridge A Level Computer Science 9608 — 2017 May/June Paper 1 · Variant 2

* 0 2 1 5 2 4 6 1 4 4 * This document consists of 13 printed pages and 3 blank pages. DC (CE/FC) 129908/3 © UCLES 2017 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level COMPUTER SCIENCE 9608/12 Paper 1 Theory Fundamentals May/June 2017 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 9608/12/M/J/17 © UCLES 2017 1 Some shops belong to the Rainbow Retail buying group. They buy their goods from one or more suppliers. Each shop has: • a unique shop ID • a single retail specialism (for example, food, electrical, garden). Each supplier has: • a unique supplier ID • a similar single specialism recorded. Rainbow Retail creates a relational database to record data about the shops and their suppliers. The entity-relationship (E-R) diagram for the relationship between the SHOP and SUPPLIER tables is shown. SHOP SUPPLIER (a) Explain what the degree of relationship is between the entities SHOP and SUPPLIER. … …[1] The database design is as follows: SHOP(ShopID, ShopName, Location, RetailSpecialism) SUPPLIER(SupplierID, SupplierName, ContactPerson, RetailSpecialism) SHOP-SUPPLIER(ShopID, SupplierID) The SHOP–SUPPLIER table stores the suppliers that each shop has previously used. Primary keys are not shown. (b) (i) Label the entities and draw the relationships to complete the revised E-R diagram. SUPPLIER [3]

3 9608/12/M/J/17 © UCLES 2017 [Turn over (ii) Complete the following table to show for each database table: • the primary key • the foreign key(s) (if any): ° Each table may contain none, one or more foreign key(s). ° For a table with no foreign key, write ‘None’. • an explanation for the use of any foreign key. Table Primary key Foreign key(s) (if any) Explanation SHOP SUPPLIER SHOP–SUPPLIER [5] (iii) The database designer has implemented SUPPLIER.ContactPerson as a secondary key. Describe the reason for this. … … … …[2] (c) (i) Write an SQL query to display the shop ID and location of all shops with a ‘GROCERY’ specialism. … … …[3] (ii) The existing shop with ID 8765 has just used the existing supplier SUP89 for the first time. Write an SQL script to add this data to the database. … … …[3]

4 9608/12/M/J/17 © UCLES 2017 2 (a) The first column of the following table gives features of different types of printer. Put a tick (3) in the cells to show which features describe a laser and an inkjet printer. Type of printer Laser Inkjet Impact printer Non-impact printer Line printer Page printer [2] (b) Two of the components of an inkjet printer are a stepper motor and a print head. Describe how each component is used when printing a page. (i) Print head … … … … … … … … …[5] (ii) Stepper motor … … …[2]

5 9608/12/M/J/17 © UCLES 2017 [Turn over (c) A student has an old working laptop computer. It has a small capacity internal disk drive with almost all the storage space taken up by the operating system and application programs. She needs to buy an external storage device to store her data files. (i) List two suitable devices. Device 1 … Device 2 … [2] (ii) Describe one advantage of choosing one of the devices. Advantage of choosing device 1 / 2 (circle) … …[1]

6 9608/12/M/J/17 © UCLES 2017 3 (a) A computer has a microphone and captures a voice recording using sound editing software. The user can select the sampling resolution before making a recording. Define the term sampling resolution. Explain how the sampling resolution will affect the accuracy of the digitised sound. Sampling resolution … … … Explanation … … [3] (b) The computer also has bitmap software. (i) Define the term image resolution. … …[1] (ii) A picture is drawn and is saved as a 16-colour bitmap image. State how many bits are used to encode the data for one pixel. …[1] (iii) A second picture has width 8192 pixels and height 256 pixels. It is saved as a 256-colour bitmap. Calculate the file size in kilobytes. Show your working. … … … … …[3] (iv) The actual bitmap file size will be larger than your calculated value as a bitmap file has a file header. State two items of data that are stored in the file header. 1 … 2 …[2]

7 9608/12/M/J/17 © UCLES 2017 [Turn over 4 (a) (i) Explain why a personal computer (PC) needs an operating system (OS). … … …[2] (ii) One of the tasks carried out by the OS is the management of the use of the processor. Name and describe two other management tasks that the OS performs. 1 … … … 2 … … … [4] (b) A user has the following issues with the use of their personal computer (PC). For each case, state the utility software which should provide a solution. (i) The user wants to send a large file as an attachment to an email. The user knows that the recipient’s Internet Service Provider (ISP) has a limit of 2MB for file attachments. Utility software solution: …[1] (ii) The user is writing a book and is worried that the document files could get damaged or deleted. Utility software solution: …[1] (iii) The computer has recently been slow to load large files. The user has deleted a large number of small files to try to solve the problem. A friend has advised that there is a procedure which should be regularly carried out to reorganise file storage on the hard disk. Utility software solution: …[1] (iv) The user clicked on an attachment in an unsolicited email. Since then, the computer has shown some unexplained behaviours. Utility software solution: …[1]

8 9608/12/M/J/17 © UCLES 2017 5 The following 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 (mnemonic) Operand Op code (binary) LDD <address> 0001 0011 Direct addressing. Load the contents of the location at the given address to the Accumulator (ACC). LDI <address> 0001 0100 Indirect addressing. The address to be used is at the given address. Load the contents of this second address to ACC. LDX <address> 0001 0101 Indexed addressing. Form the address from <address> + the contents of the Index Register. Copy the contents of this calculated address to ACC. LDM #n 0001 0010 Immediate addressing. Load the denary number n to ACC. LDR #n 0001 0110 Immediate addressing. Load denary number n to the Index Register (IX). STO <address> 0000 0111 Store the contents of ACC at the given address. The following diagram shows the contents of a section of main memory and the Index Register (IX). (a) Show the contents of the Accumulator (ACC) after each instruction is executed. IX 0 0 0 0 0 1 1 0 (i) LDD 355 ACC … [1] (ii) LDM #355 ACC … [1] (iii) LDX 351 ACC … [1] (iv) LDI 355 ACC … [1] Address Main memory contents 350 351 86 352 353 354 355 351 356 357 22 358

9 9608/12/M/J/17 © UCLES 2017 [Turn over (b) Each machine code instruction is encoded as 16 bits (8-bit op code followed by an 8-bit operand). Write the machine code for these instructions: LDM #67 LDX #7 [3] (c) Computer scientists often write binary representations in hexadecimal. (i) Write the hexadecimal representation for the following instruction. 0 0 0 1 0 1 0 0 0 1 0 1 1 1 1 0 …[2] (ii) A second instruction has been written in hexadecimal as: 16 4D Write the assembly language for this instruction with the operand in denary. …[2]

10 9608/12/M/J/17 © UCLES 2017 6 Downloading a file from a website is an example of a client-server application. (a) Describe what is meant by the term client-server for this application. … … … …[2] (b) The following sequence of steps (1 to 5) describes what happens when someone uses their personal computer (PC) to request a web page. The web page consists of HTML tags and text content only. Four of the statements from A, B, C, D, E and F are used to complete the sequence. A Browser software interprets the script, renders the page and displays. B Browser software renders the page and displays. C Browser software compiles the script, renders the page and displays. D The web server retrieves the page. E The Domain Name Service (DNS) uses the domain name from the browser to look up the IP address of the web server. F The web server sends the web page content to the browser. Write one of the letters A to F in the appropriate row to complete the sequence. 1. The user keys in the Uniform Resource Locator (URL) into the browser software. 2. … 3. … 4. … 5. … [4]

11 9608/12/M/J/17 © UCLES 2017 [Turn over Question 6(c) begins on the next page.

12 9608/12/M/J/17 © UCLES 2017 (c) The following web page used for data capture consists of: • two text boxes for the entry of: ° a race runner’s ID code ° their finishing position in a race. • a button that the user clicks to submit this runner’s result. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 <html> <head> <title>Untitled Document</title> <script language="JavaScript"> function myButton_onmousedown() { var Output1 = "Runner ID OK"; var Output2 = "ERROR – entry refused"; var Runner ID = document.forms["form1"]["txtRunnerID"].value; // || in Javascript is the 'OR' operator if (RunnerID.substr(0,3) == "VAR" || RunnerID.substr(0,3) == "CAM") { alert(Output1) } else { alert(Output2) } } </script> </head> <body> <form name = form1> <label>Runner ID: </label> <input type="text" name="txtRunnerID" > <label>Position: </label> <input type="text" name="txtPosition" size = "5" > <p> <label>Save data: </label> <input type="button" name="btnSubmit" Value = "Submit" onMouseDown = "myButton_onmousedown()" > </p> </form> </body> </html>

13 9608/12/M/J/17 © UCLES 2017 (i) The developer has used three variables in the JavaScript code. State the identifiers used. 1. … 2. … 3. … [2] (ii) The button has an event whose identifier is onMouseDown. When the mouse button is clicked, some code is run. State the line numbers which contain this code. From line … to line … [1] (iii) The JavaScript code uses a selection statement. State the line number which contains its condition. Line number: … [1] (iv) Describe the purpose of the validation check that the code performs. … …[1] (v) Name and describe two other types of validation check which could be appropriate for this data capture form. Validation check: … Description … … Validation check: … Description … … [4]

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® IGCSE is a registered trademark. This document consists of 7 printed pages. © UCLES 2017 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level COMPUTER SCIENCE 9608/12 Paper 1 Written Paper May/June 2017 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 will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2017 series for most Cambridge IGCSE®, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 2 of 7 Question Answer Marks 1(a) Many-to-many relationship 1 1(b)(i) Both entities correctly labelled 1 Correct relationship between SHOP and SHOP-SUPPLIER 1 Correct relationship between SUPPLIER and SHOP-SUPPLIER 1 3 1(b)(ii) Table Primary key Foreign keys(s) (if any) Explanation SHOP ShopID None SUPPLIER SupplierID None SHOP-SUPPLIER ShopID AND SupplierID ShopID OR SupplierID (or both) To create a link with the SHOP or SUPPLIER table. • SHOP has primary key ShopID and SUPPLIER has primary key SupplierID 1 • SHOP-SUPPLIER has primary key ShopID + SupplierID 1 • Both SHOP and SUPPLIER show foreign key as ‘None’ 1 • SHOP-SUPPLIER shows foreign key ShopID or SupplierID 1 • Explanation for SHOP-SUPPLIER foreign key describes ShopID or SupplierID creating a link 1 5 1(b)(iii) Two from: • The database user will frequently want to search on contact name 1 • The contact name attribute has been indexed 1 • It allows for a fast/faster search using contact name 1 Max 2 1(c)(i) SELECT ShopID, Location 1 FROM SHOP 1 WHERE RetailSpecialism = 'GROCERY'; 1 3 1(c)(ii) INSERT INTO SHOP-SUPPLIER 1 (ShopID, SupplierID) 1 VALUES (8765, 'SUP89'); 1 3

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 3 of 7 Question Answer Marks 2(a) One mark for each pair of rows Type of printer Laser Inkjet Impact printer 1 Non-impact printer 9 9 Line printer 9 1 Page printer 9 2 2(b)(i) Five from: • The print head contains a large number of very small nozzles 1 • Ink is fed to each nozzle from a reservoir 1 • The print head fires droplets of ink onto the paper 1 • The print head moves horizontally across the paper 1 Either: • Tiny resistors create heat inside each nozzle 1 • The heat vaporises ink to create a bubble 1 • When the bubble pops the ink is deposited on the page 1 • The collapsing bubble creates a partial vacuum in the nozzle 1 • And ink is drawn from the reservoir ready for printing the next dot 1 Or: • There is a piezo crystal at the back of the ink reservoir of each nozzle 1 • The crystal vibrates when it receives a tiny electric charge 1 • Ink is forced out of the nozzle by the inward vibration 1 • The outward vibration creates a partial vacuum in the nozzle 1 • Replacement ink is pulled into the reservoir 1 Max 5 2(b)(ii) Two from: • The (print head) stepper motor is connected to the print head by a belt 1 • The (print head) stepper motor moves the print head across the paper 1 • The (parking) stepper motor parks the print head assembly when not in use 1 • The (paper feed)stepper motor turns the rollers that provide the paper feed // The (paper feed)stepper motor moves the paper in small increments 1 Max 2 2(c)(i) Two from: • External hard drive // External HDD 1 • External flash drive // External SSD 1 • Pen drive 1 Max 2

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 4 of 7 Question Answer Marks 2(c)(ii) One from: (External) Hard drive Inexpensive per unit of storage 1 Larger storage capacity than flash drive 1 Or: Pen drive // (External) flash drive No moving parts / noise 1 Low latency // fast access times 1 Robust 1 Max 1 Question Answer Marks 3(a) Definition: Max two from: • The number of distinct values available to encode/represent each sample 1 • Specified by the number of bits used to encode the data for one sample 1 • Sometimes referred to as bit depth 1 Explanation: Max two from: • A larger sampling resolution will mean there are more values available to store each sample 1 • A larger sampling resolution will improve the accuracy of the digitised sound // A larger sampling resolution will decrease the distortion of the sound 1 • Increased sampling resolution means a smaller quantization error 1 Max 3 3(b)(i) One from: • The number of pixels per unit measurement 1 • The number of pixels in an image 1 • The number of pixels wide by the number of pixels high 1 • Number of pixels per row by the number of rows 1 1 3(b)(ii) 4 1 3(b)(iii) Working: Max two from: • Number of pixels is 8192 × 256 1 • One pixel will be stored as one byte 1 • Number of kilobytes = (8192 × 256) / 1024 1 Answer: One mark: Number of kilobytes = 2048 KB 1 3 3(b)(iv) Two from: • Confirmation that the file is a BMP 1 • File size 1 • Location/offset of image data within the file 1 • Dimensions of the image (in pixels) // image resolution 1 • Colour depth (bits per pixel, 1, 4, 8, 16, 24 or 32) 1 • Type of compression used, if any 1 Max 2

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 5 of 7 Question Answer Marks 4(a)(i) Two from: • The hardware is unusable without an OS // hides complexity of hardware from user 1 • Acts as an interface/ controls communications between user and hardware / hardware and software // or by example 1 • Provides software platform / environment on which other programs can be run 1 2 4(a)(ii) One mark for the name and one mark for description. Max two management tasks. • Provides the Human Computer Interface (HCI) 1 Controls communications between user and hardware// or by example 1 • Main memory management 1 Memory protection to ensure that two programs do not try to use the same space // Use of virtual memory // Location of processes within the memory // By example 1 • File / Secondary storage management 1 Maintains directory structures // Provides file naming conventions // Controls access 1 • Peripheral / hardware / device / Input-Output management 1 Installation of appropriate driver software // Controls access to data being sent to/from hardware/peripherals // Controls access to hardware/peripherals // manages communication between devices. 1 • Interrupt handling 1 Identifies priorities of interrupts // Saves data on power outage // Loads appropriate Interrupt Service Routine (ISR) // By example 1 • Security management 1 Makes provision for recovery when data is lost // Provides usernames and passwords // Prevents unauthorised access // Ensures privacy of data 1 Max 4 4(b)(i) File compression software 1 4(b)(ii) Backup software 1 4(b)(iii) Disk defragmenting software 1 4(b)(iv) Anti-virus software 1 Question Answer Marks 5(a)(i) 351 1 5(a)(ii) 355 1 5(a)(iii) 22 1

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 6 of 7 Question Answer Marks 5(a)(iv) 86 1 5(b) Op code Operand 0 0 0 1 0 0 1 0 0 1 0 0 0 0 1 1 0 0 0 1 0 1 0 1 0 0 0 0 0 1 1 1 Both correct op codes 1 Operand 0100 0011 1 Operand 0000 0111 1 3 5(c)(i) 14 5E 14 1 5E 1 2 5(c)(ii) LDR #77 LDR 1 #77 1 2

9608/12 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2017 © UCLES 2017 Page 7 of 7 Question Answer Marks 6(a) Two from: • The file is made available from a web/email/FTP server 1 • The user’s browser is the client software 1 • The client (software browser) requests the file from the server 1 • The desired file is returned to the client computer 1 Max 2 6(b) 1. The user keys in the Uniform Resource Locator (URL) into the browser Software. 2. E // The Domain Name Service (DNS) uses the domain name from the browser to look up the IP address of the web server. 1 3. D // The web server retrieves the page 1 4. F // Sends the web page content to the browser 1 5. B // Browser software renders the page and displays 1 4 6(c)(i) Output1, Output2 1 RunnerID // Runner ID 1 2 6(c)(ii) 6 – 21 1 6(c)(iii) 13 1 6(c)(iv) Checks that the RunnerID entered starts with the characters CAM or VAR only 1 6(c)(v) Two checks from: One mark for check and one mark for description • Format check 1 RunnerID is three letter characters followed by two digit characters //Position is digit characters only 1 • Length check 1 RunnerID has exactly five characters 1 • Range check 1 The value for Position is between1 and (say) 50 1 • Presence check 1 The text box for RunnerID or Position is not empty 1 • Existence check 1 To ensure that RunnerID has been registered 1 • Uniqueness check 1 To ensure no two runners have the same number 1 Max 4