Cambridge IGCSE Computer Studies 0420 — 2013 Oct/Nov Paper 1 · Variant 3

This document consists of 20 printed pages. IB13 11_0420_13/4RP © UCLES 2013 [Turn over *9205514197* For Examiner's Use UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education COMPUTER STUDIES 0420/13 Paper 1 October/November 2013 2 hours 30 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, 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. www.XtremePapers.com

2 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 1 (a) Name three features of a typical data protection act. 1 2 3 [3] (b) Data being held is often referred to as Personal or Sensitive Personal data. Give two examples of each type of data. Personal Data 1 2 Sensitive Personal Data 1 2 [4]

3 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use 2 (a) The training department of an international airline has introduced computer based training (CBT) to teach foreign languages to its cabin crew. Give two advantages of using CBT. 1 2 [2] (b) The airline also trains its pilots. (i) What type of training is most appropriate to train pilots to manage dangerous situations? [1] (ii) Give two benefits of using this type of training. 1 2 [2]

4 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 3 Dmitry’s car is fitted with a Global Positioning System (GPS) navigation system. (a) Explain how the GPS system knows the exact location of Dmitry’s car. [3] (b) Dmitry’s GPS system gives out verbal instructions. (i) Give one benefit and one drawback of doing this. benefit drawback [2] (ii) Dmitry turns his car onto a main road. His GPS system tells him that he is not on a road. Give a possible explanation. [2]

5 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use 4 A customer logs on to a bank website so that she can access her account. (a) The first thing she was asked to do was to give the 3rd, 4th and 7th character of her password. This was done using drop-down boxes: Give two reasons why the customer was asked to supply only 3 characters from her password. 1 2 [2] (b) Authentication is a technique used in bank security to check that the customer is who they say they are. This involves three pieces of information, other than the password, all related to the customer. Give three examples of suitable information: 1 2 3 [3]

6 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 5 A website has been set up allowing users to access the Periodic Table. Part of the table is shown below. H Li Na K He Ne Ar Kr Be Mg Ca B Al Ga C Si Ge N P As O S Se F Cl Br Sc Ti V Cr Mn Fe Co Ni Cu Zn A user selects an element from the table and is then directed to another web page where details of the chosen element can be found. (a) (i) What would be the most suitable input device for this application? [1] (ii) Describe how your chosen input device would interact with the table. [1] (b) Give two advantages of this system when compared to finding the same information from books. 1 2 [2] (c) Apart from security issues, give two disadvantages of this system compared to using books. 1 2 [2]

7 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use 6 Patients in a hospital are monitored for vital signs (for example, heart beat and temperature) by sensors and a computer system. Results are displayed on a monitor in the form of numbers and graphs. (a) Describe how the sensors and computer system are used to monitor the patients and to alert doctors and nurses of a possible problem. [3] (b) Give two advantages of using this system rather than 24 hour monitoring by nurses. 1 2 [2] (c) Why is the output shown in both graphical and numerical form? [2]

8 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 7 (a) Describe what is meant by streaming when watching a video on a computer screen. [2] (b) What is the difference between true (real time) streaming and on demand streaming? true on demand [2] (c) To allow high quality video playback during streaming, computers need special software and a way of temporarily saving the data. Describe one piece of software needed and also how the data can be stored temporarily. software temporary storage [2]

9 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use (d) Give one benefit and one drawback of using streaming to play videos. benefit drawback [2]

10 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 8 A company decides to offer a computer aided design (CAD) service. (a) Give two advantages and two disadvantages to the designer of using CAD rather than using manual, paper-based systems. Advantages: 1 2 Disadvantages: 1 2 [4] (b) The company sets up call centres overseas to help give customers advice. (i) Give two benefits to the company. 1 2 [2] (ii) Give two drawbacks to the company. 1 2 [2]

11 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use 9 A database was set up to keep track of goods in a shop. A section of the database is shown below. Item code Number in stock Re-order level Price of item ($) Value of stock ($) Items ordered 1113 155 200 1.50 232.50 Yes 1124 84 50 2.50 210.00 No 1200 30 60 5.00 150.00 Yes 1422 600 500 1.00 600.00 No 1515 90 100 2.00 180.00 No 1668 58 50 4.00 232.00 No 1801 60 100 8.00 480.00 No 1844 195 200 1.50 292.50 Yes (a) How many records are shown in this section of database? [1] (b) (i) Using Item code only, what would be output if the following search was carried out: (Number in stock < Re-order level) AND (Items ordered = “No”) [2] (ii) What useful information does this search produce? [1] (c) Write a search condition to locate items costing more than $2.00 or have a stock value exceeding $300.00. [2]

12 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 10 (a) The following pseudocode was written to input 1000 dates. 1 count = 1 2 repeat 3 input day, month, year 4 count = count + 1 5 until count = 1000 (i) Describe why the loop only inputs 999 dates instead of 1000. [1] (ii) What needs to be changed or added to the above code to make sure 1000 dates are input? [1] (b) Errors in code can be found using test data. Name three different types of test data. Using month from the pseudocode above, give an example of each type of test data. test data type 1 example test data type 2 example test data type 3 example [6]

13 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use 11 (a) Draw the logic circuit for the following logic statement: X = 1 if [ A is NOT 1 AND B is 1 ] AND [ B is 1 OR C is 1 ] A B X C [4] (b) Complete the truth table for the above 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]

14 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 12 A spreadsheet was set up to compare fuel prices in dollars per litre over three years. Part of the spreadsheet is shown below. A B C D E F 1 Year 1 ($/litre) Year 2 ($/litre) Year 3 ($/litre) Average ($/litre) Above world average in year 3? 2 country 1 2.00 2.40 2.75 2.38 3 country 2 2.50 2.70 2.90 2.70 4 country 3 2.00 2.10 2.30 2.13 5 country 4 1.00 1.25 1.40 1.22 6 country 5 2.00 2.20 2.50 2.23 7 country 6 2.20 2.80 3.00 2.67 8 country 7 2.15 2.45 2.80 2.47 9 country 8 1.50 1.70 2.00 1.73 10 Max value: 3.00 (a) What formulas must be in column E to calculate the average values for years 1 to 3? E 1 Average ($/litre) 2 = 3 = 4 = 5 = 6 = 7 = 8 = 9 = [2] (b) What formula must be in cell D10 to find the highest fuel value in $/litre for year 3? = [1] (c) (i) If the following formula was typed into cell F2, what would be output? = IF (D2 > 2.20, “Y”, “N”) [1]

15 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use (ii) If the formula from part (c)(i) was replicated all the way down to F9, what values would be shown in cells F2 to F9? F 1 Above world average in year 3? 2 3 4 5 6 7 8 9 [2] (d) (i) If the following formula was typed into cell E10, what would be output? = COUNTIF (E2:E9, “> 2.20”) [1] (ii) What formula would need to be in cell F10 to count the number of “Y” entries in column F? = [1]

16 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 13 A touch screen is divided up into a number of locations: 0 0 1 1 61 62 63 2 2 30 31 … … x values y values Each x-position is shown in a 6-bit register: 32 16 8 4 2 1 and each y-position is shown in a 5-bit register: 16 8 4 2 1 Thus, 0 32 1 16 1 8 1 4 1 2 0 1 1 16 0 8 1 4 0 2 1 1 refers to screen position: (30, 21) (a) Give the screen position referred to if the two registers contain: 1 32 1 16 0 8 1 4 0 2 0 1 0 16 1 8 1 4 1 2 0 1 ( , ) [2]

17 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use (b) Three options (A, B, C) are shown on the touch screen below: position (40, 11) position (20, 11) B A position (30, 25) C If the two registers contain: 1 32 0 16 1 8 0 4 0 2 0 1 0 16 1 8 0 4 1 2 1 1 what option (A, B or C) has been chosen? [1] (c) Each box A, B, C is made up of 128 x 64 pixels. (i) What is meant by the term pixel? [1] (ii) The value of each pixel is stored in 1 byte of memory. How much memory is needed to store one of these boxes? Give your answer in kilobytes. [2]

18 © UCLES 2013 0420/13/O/N/13 For Examiner's Use 14 A microprocessor controls the opening and closing of automatic doors to a supermarket. Customers are detected using pressure sensors. The flowchart on the next page shows how the sensors and microprocessor interact to control the opening and closing of the doors. However, several of the stages in the process have been missed out. Using item number only, complete the flowchart using items from the following list: Item number Item description 1 ADC changes analogue signal into digital signal 2 are the doors already open? 3 DAC changes digital signal into analogue signal 4 DAC changes digital signal into analogue signal 5 doors are closed 6 microprocessor sends signal 7 microprocessor sends signal 8 no action is required 9 wait for 10 seconds

19 © UCLES 2013 0420/13/O/N/13 [Turn over For Examiner's Use START has sensor detected a customer? doors are opened has sensor detected a customer? Yes No No No Yes Yes [5]

20 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. University of 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. © UCLES 2013 0420/13/O/N/13 For Examiner's Use 15 5000 numbers are being input which should have either 1 digit (e.g. 5), 2 digits (e.g. 36), 3 digits (e.g. 149) or 4 digits (e.g. 8567). Write an algorithm, using pseudocode or flowchart only, which • inputs 5000 numbers • outputs how many numbers had 1 digit, 2 digits, 3 digits and 4 digits • outputs the % of numbers input which were outside the range [6]

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2013 series 0420 COMPUTER STUDIES 0420/13 Paper 1; maximum raw mark 100 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 October/November 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components. www.XtremePapers.com

Page 2 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 1 (a) Any three from: – data should be obtained/processed fairly/lawfully – data should be obtained only for one or more specified purposes – data should be adequate/relevant/not excessive (in relation to its purpose) – data should be accurate/up to date – data should be held no longer than necessary (for the purpose for which it was obtained) – data should be processed in accordance with the rights of the data subjects – data should be kept securely/safely (with adequate levels of protection) – data should only be transferred to countries with an adequate level of protection (safe harbour) – data subjects have the right to see data about them and/or have it altered/removed if incorrect [3] (b) Personal data: any two from: e.g. – name (surname and/or forename) – address – telephone/mobile number – passport/id number – date of birth – email address Sensitive personal data: any two from: e.g. – racial/ethnic origin – political opinions – religious beliefs – Trades Union membership – physical/mental health – sexual life/orientation – criminal convictions [4] 2 (a) Any two from: – user can work at their own speed – user can learn in their own time/when/where they want – user can re-run sections of training package whenever they wish – user can pause the training at any point – user gets immediate feedback/analysis (on their performance) – there is no need to have teachers or classrooms – less expensive for the airline/ training department [2] (b) (i) flight simulator/simulating/simulation [1] (ii) Any two from: – can be much safer – less expensive than building/crashing the real thing – repetition of scenarios (e.g. potential crashes) – different scenarios/situations available – no need for an instructor [2]

Page 3 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 3 (a) Any three from: – satellites transmit signals (to the GPS in the car) – the computer receives/interprets these signals – the system depends on very accurate timing/atomic clocks – each satellite transmits its location and time – computer in the vehicle calculates its position based on at least 3 satellite signals – system makes use of triangulation (to pinpoint its exact location) – position of vehicle accurate to within 1 metre – at least 24 satellites in operation [3] (b) (i) benefits (any one from) – safer because e.g. driver can keep their eyes on the road – verbal instructions can be easier/quicker to understand by driver – a comparative safety issue drawbacks (any one from) – can be distracting to the driver – may not hear instructions (clearly) – inappropriate words [2] (ii) Any two from: – maps in GPS (sat nav) may be out of date/new road – position of the car is in error – fault in software in device – interference/loss of signal e.g. due to weather [2] 4 (a) Any two from: – hackers only get part of the password – can ask for different characters/combinations each time – helps to “defeat” spyware [2]

Page 4 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 (b) Any three from: customer knows: e.g. – PIN – Name/user name – date last logged on – memorable word/phrase/graphic – memorable personal data e.g. mother’s maiden name – date of birth – email address – recent activities – telephone number – customer number – account number belongs to customer: – bank card (number) unique to customer: – biometrics (e.g. fingerprints) [3] 5 (a) (i) Any one from: – touch screen – mouse/trackerball/touch pad – keyboard [1] (ii) Any one from: – touch required element on screen with finger (and go to relevant web page) – pointer moved and element selected (mouse/trackerball/touch pad) – use arrow keys on keyboard to select required element and then press [ENTER] key OR key characters and press [ENTER] [1] (b) Any two from: – much faster/easier to access information – more up to date (since easier to modify than books) – more convenient than carrying around many text books – many people can access the data at the same time – using multi-media (possible to improve learning environment) – easier to import information into an “essay” (for example) [2]

Page 5 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 (c) Any two from: – Accuracy issues e.g. anyone can write a web page, information is limited to author’s knowledge – health and safety risks from prolonged use of computer – risk of finding undesirable web sites – possibility of information overload when doing searches – Internet access required – Power source required [2] 6 (a) Any three from: – sensors for oxygen, heart/pulse rate (etc.) send signals to computer – converted (by ADC) into digital data – computer compares this data with stored data/pre-set values sends vital signs data to monitors – if the new information is out of range, computer sends signals – to sound an alarm/warn doctors and nurses – signals need to be first converted into analogue (by DAC) – monitoring is continuous (until machine is switched off) [3] (b) Any two from: – nurse issues e.g. nurses get tired, need breaks – can show immediate trends (automatically) – faster response to a given set of conditions – less expensive because e.g. leaves nurses free to do other tasks while computer monitors patients, less wages [2] (c) Any two from: – easier to see immediate trends in data using a graph – “OK” graph and “not OK” graph may be easier to recognise at a glance – numbers are easier to read in some cases (e.g. temperature) – no need to interpret/understand numbers [2] 7 (a) Any two from: – data sent in a compressed form – over the Internet – displayed to user in real time – makes use of buffering [2] (b) true (any one from) – information sent straight to user’s computer – no need to save information first on servers’ hard disk – data is live (in real time) on demand (any one from) – files saved on servers’ hard disk first – then played back to user as required [2]

Page 6 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 (c) software (any one from) – media player – decompression software – CODEC temporary storage – use of buffers [2] (d) benefit (any one from) – no need to store the files/saves on memory space – can be sent directly to any receiving device – available anytime drawback (any one from) – slow due to e.g. buffering, broadband speed – video “gaps”/jumps as data is streamed – video withdrawn [2] 8 (a) Advantages (any two from) – easier to modify the drawings – can keep a “library of parts” – special features available e.g. zoom, rotation – can do automatic costings – easier to create a model from the design – easier to do ergonomic studies on new designs – can automatically carry out stress/loading calculations – direct link into CAM is possible Disadvantages (any two from) – possible need for training – higher costs e.g. start-up, on-going [4] (b) (i) benefits (any two from) – reduced costs in countries where labour costs are lower – reduced costs in countries where incentives are given to set up companies – round the clock (24/7) customer support is possible – if workers on strike in one country, can move work somewhere else [2] (ii) drawbacks (any two from) – language and culture problems can make it difficult for company – possible negativity to overseas call centres (loss of customers) – need for (expensive) training programmes – start-up costs – possible unreliability of infrastructure [2]

Page 7 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 9 (a) 8 [1] (b) (i) 1515 1801 (–1 mark for each error) [2] (ii) – checks whether new goods have (yet) to be ordered – to maintain stock levels [1] (c) (Price of item ($) > 2) OR (Value of stock ($) > 300) < - - - - 1 mark - - - - > < - - - - - - - - - 1mark - - - - - - - - > or (Value of stock ($) > 300) OR (Price of item ($) > 2) < - - - - - - 1 mark - - - - - -> < - - - - - - - 1mark - - - - - - > [2] 10 (a) (i) – value of count starts at 1 so only 999 iterations – value of count reaches 1000, but before 1000th input (ii) – line 1 should read count = 0 – line 5 should read count = 1001 (or count >1000) – change to appropriate loop structure [2] (b) – 1 mark for naming data type + 1 mark for example related to month – normal/valid (test data) – any value in given range (1 to 12) e.g. 4 – abnormal/invalid (test data) – any value which is outside the range/any value not acceptable – i.e. letters, negative numbers, values > 12 e.g. adfrk, -20, 36 – extreme/boundary (test data) – data which is on the boundaries/edges of the acceptable range – i.e. 1 or 12 for extreme; 0, 1, 12 or 13 for boundary – Month names, instead of values, are acceptable e.g. April [6]

Page 8 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 11 (a) (1 mark for EACH correct logic gate) [4]

Page 9 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 (b) A B C X 0 0 0 0 0 0 1 0 0 1 0 1 0 1 1 1 1 0 0 0 1 0 1 0 1 1 0 0 1 1 1 0 [4] } } } } 1 mark 1 mark 1 mark 1 mark

Page 10 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 12 (a) [2] (b) MAX (D2:D9) [1] E 1 Average ($/litre) 2 = AVERAGE (B2:D2) 3 = AVERAGE (B3:D3) 4 = AVERAGE (B4:D4) 5 = AVERAGE (B5:D5) 6 = AVERAGE (B6:D6) 7 = AVERAGE (B7:D7) 8 = AVERAGE (B8:D8) 9 = AVERAGE (B9:D9) –1 for each error Working equivalents acceptable Allow follow through

Page 11 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 (c) (i) Y or “Y” [1] (ii) [2] (d) (i) 5 [1] (ii) = COUNTIF (F2:F9, “Y”) [1] 13 (a) (52, 14) 1 mk 1 mk [2] (b) B [1] (c) (i) – smallest element that makes up a picture – short for picture element [1] (ii) 128 × 64 = 8192 bytes of memory = 8 kilobytes (2 marks for correct answer, 1 mark for good attempt at calculation) [2] F 1 Above world average in year 3? 2 Y 3 Y 4 Y 5 N 6 Y 7 Y 8 Y 9 N 1 mark 1 mark

Page 12 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 14 [5] has sensor detected a customer? 9 No Yes Yes No Yes No 1 mark 1 mark 1 mark 1 mark 1 mark 1 2 8 6/7 3/4 doors are opened 7/6 4/3 5 START has sensor detected a customer?

Page 13 Mark Scheme Syllabus Paper IGCSE – October/November 2013 0420 13 © Cambridge International Examinations 2013 15 marking points: – initialisation 1 mark – correct loop structure (1 to 5000) 1 mark – input numbers (INSIDE a loop) 1 mark – test for how many digits in all input numbers 1 mark – increment all relevant totals 1 mark – increment error total as appropriate 1 mark – calculate % errors in input numbers 1 mark – output ALL four totals + percent value (OUTSIDE a loop) 1 mark sample coding: single = 0: two = 0: three = 0: four = 0: error = 0 1 mark for x = 1 to 5000 1 mark input number 1 mark if number > 999 and number < 10000 then four = four + 1 } else if number > 99 then three = three + 1 } 2 else if number > 9 then two = two + 1 } marks else if number > 0 then single = single + 1 } else error = error + 1 1 mark next x percent = error/50 1 mark print single, two, three, four, percent 1 mark [6]