Information Technology 9626/12 February/March 2023: question paper and mark scheme

Mark scheme

1(a) ONE from: 1 • Information should be/that is free from errors/mistakes (1) • Information should be/that is true/correct (1) • Information that is provable/proven to be correct (1) 1(b) SIX from: 6 • People might not answer the questionnaire truthfully (1) • People might answer the interview truthfully (1) • People may be biased (1) • The questions might be badly phrased (1) • Interviews can clarify the answer (1) • Interviews can ask questions based on previous answers (1) • Questionnaires cannot expand on what the question means (1) • Interviews include open ended questions that are hard to quantify (1) • In a multi choice type question there may not be a sufficient number of alternatives//answers restricted to those provided (1) • There is the possibility that the people collecting the data may make errors when collecting it (1) 1(c) ONE from: 1 • User is in communication with a central computer (1) • Where a process is carried out on the internet/WWW (1) 1(d) Five from: 5 • Go to the website (1) • Log on (by entering username and password) (1) • Choose goods category (1) • Choose/select item (to examine the product) (1) • Add (items) to shopping basket/cart //click on buy button//pick up item (1) • Check good in basket/cart//make changes to goods in basket/cart (1) • Click on/proceed/go to checkout (1) • Confirm billing address (1) • Confirm/enter delivery address (1) • Choose method of delivery (1) • Select/use payment method (1) • Type in credit card/debit card number (1) • Enter card security code/last three digits of CVV/CVC/CSC (1) • Confirm order//click checkout button//click pay (1) (NO further marks to be given after this mark given, unless candidate clearly states that the action happens before this point)

Mark scheme

2 Up to Six marks available: 6 Benefits Max 5 • Programs can be written in modules (1) – …which requires less RAM (1) – ... so saving cost of memory (1) • Whole program and compiler don’t need to be in memory at the same time (1) – …which requires less RAM (1) – ... so saving cost of memory (1) Both extension marks above may be given twice (once per first mark item) where used appropriately. • A number of programmers can be used to write separate modules … (1) – …which saves time compared to one person writing the whole code (1) • If there is an error in the code only that module has to be corrected (1) Drawbacks • Variable names can cause problems... (1) – ...the same variable may have been given different variable names in different modules (1) • Documentation has to be more detailed … (1) – … so takes longer to write (1) Max. five marks if bullets/list of points

Mark scheme

3 SIX marks available: 6 Benefits (MAX 4) • Protects from computer viruses/malicious code (accept either ‘finds’ or ‘stops new infections’ (1) • Prevents data/files (in files) becoming corrupted/deleted (1) • Can prevent passwords from being changed (1) • Can prevent user’s email account sending out spam (1) • Can prevent computer from crashing (1) • User can select how regularly the anti-virus scan is to take place (1) • User can select which files to scan (1) • Quarantines any infected files (removes BOD) (1) Drawbacks (MAX 4) • Anti-virus software can cost//has to be purchased (any awareness of cost or expense) (1) • Only purchase for one year (1) • Anti-virus needs to be kept up to date …(1) – …because there always new virri to be countered (1) • Anti-virus can only detect a virus if it is listed in the AV database (1) • Anti-virus background scans can slow a computer down//slow down download process (1) • Can give a false sense of security/does not give 100% coverage (1) • Can result in false positives (award as a concept, not necessarily these words) …(1) – …what appears to be suspicious activity turns out to be harmless (1) • Needs expertise to personalise (1) Accept examples such as – “Can take a long time to customise account/settings”. • Takes up space on the hard drive (1) • Can only delete the whole file that is infected (1) Max. five marks if bullets/list of points

Mark scheme

4(a) Start Is the no system activated? Yes MP1 Input mlevel Stop no is mlevel > dry? yes no is sprinkler no is sprinkler off? on? R yes yes (send signal to (send signal to actuator to) actuator to) switch switch sprinkler off sprinkler on SIX marks available: • Yes/No in correct position off first decision box (1) • Two other Yes/No used (off a decision) (1) – A further Yes/No used (off a decision) (1) • Input MLevel in correct place (1) • Is sprinkler on/is sprinkler off added in correct place (1) MLevel>dry NO branch: • Is Sprinkler OFF – YES – switch Sprinkler ON in correct place (1) OR • Is Sprinkler ON – NO – switch Sprinkler ON in correct place (1) MLevel >dry YES branch • Is Sprinkler ON -YES- switch Sprinkler OFF in correct place (1) OR • Is Sprinkler OFF – NO – switch Sprinkler OFF in correct place (1) For final four mark points, marks may only be awarded where the logic leading up to the decision matches that given here and is shown in full. 4(b)(i) 1 4(b)(ii) ONE from: 1 • The name of the subroutine (1) • Start (1)

Mark scheme

5 FOUR from: 4 • (Using data encryption is) a way to keep their data secure//to protect their information from a hacker //to safely exchange data (1) • Information needs to be impossible to understand/unreadable/indecipherable (1) • Information needs to be useless to a 3rd party if intercepted/hacked/they should not have it (1) • Only authorised people/people with the key can understand the information (1) • Encrypted data needs to be decrypted which is hard/impossible (without the key) (1) • To make hacking not worthwhile (1)

Mark scheme

6(a)(i) One mark for description, one mark for example: 2 • Measures/detects light intensity//how much light hitting a surface//level of light (1) • Any suitable example of use – e.g. Used in weather stations to measure the amount of sunshine – Test match cricket to see if its bright enough to play (1) 6(a)(ii) One mark for description, one mark for example: 2 • Measures temperature value (1) • Any suitable example of use – Used in weather stations to measure the temperature (1) 6(b) SIX from: 6 One point calibration Max 2 • Is the easiest method to carry out (1) • Only one point of data is used (1) • Can only be used when measuring set/constant physical variables… (1) – …therefore has a limited use (1) • Two-point calibration Max 3 • Is more complex than one point calibration (accept less complex answer)… (1) – …because is needed when a range of values is being monitored (1) • Two points of data are used (1) • Needs to be used where a linear relationship between sensor readings and the variable being monitored exists… (1) – …therefore, cannot be used when the relationship is a curve (1) • Multi point calibration Max 3 • Multi-point calibration is the most complex method… (1) – used for non-linear, multipoint relationships (1) • Multiple points of data are used (1) • Multi-point calibration is the most complex method… (1) – …greater knowledge of maths is needed (1) Max. five marks if all three methods not covered Max. five marks if bullets/list of points

Mark scheme

7 FIVE from: 5 • Uses email to collect/gather/persuade to give personal information/data (award any concept of 3rd party getting access to personal data) (1) • Any statement that email or website look legitimate/real, but is/are in fact fake/from a hacker/criminal (1) • The email usually contains something that demands the target's (immediate) attention (1) • Any suitable example of a message/scenario demanding attention (1) – EITHER • The email may ask customer to reply (1) • Target asked to enter their information (1) – OR • The email includes a website URL/link (inviting the receiver to go to the site) (1) • Clicking on/opening the link takes them to a fake/malicious website (1) • Target asked to enter their information (1)

Mark scheme

8 FIVE from: 5 • Some people in developing countries have no actual postal address making the delivery of goods which are purchased online difficult (1) • Many people in developing countries have no access to broadband so speed of purchase is slower (1) • Many people in developing countries have no PCs/laptops/smartphones/tablet computers so need to borrow a PC/go to a library (1) • In developing countries power outages can mean that connection is lost during the process and so have to start again/lose the sale (1) • Many people in developing countries do not have bank accounts and credit cards so have to organise for someone else to buy the product on their behalf (1) • In many developing countries, goods bought using the internet are not covered by consumer-protection laws so people have no protection from unscrupulous sellers (1)

Mark scheme

9(a) FOUR from: 4 • A (standalone) malicious computer program/code (1) • A program that replicates itself in order to spread to other computers (1) • Does not need to attach itself to an existing program/file (1) • Worms consume bandwidth, slowing down the (traffic in a) network (1) • Worms consume processing power, therefore (e.g.) slowing down computer operation/system//stopping the computer from operating (1) • A worm exploits (security) holes in networks/computers (1) • They replicate themselves occupying (more) space (1) • Can modify/delete files//bring other (malicious) software//install backdoor (1) 9(b) FOUR from: 4 • A malicious computer program which is used to hack into a computer (1) • Misleads users of its true intent/disguises itself as authentic software (1) • Enables the person who created it to take control of the computer it has infected (1) • Trojans (generally) do not attempt to infect other files (1) • They do not attempt to self-replicate themselves (1) • Has to be/is activated by (e.g.) the target person (1) ONE mark for any further action a Trojan may perform (1) e.g. • Provide a backdoor onto your computer so a 3rd party can take control • Delete files from the hard disk • Copies data/files • Can corrupt data (damage = TV) • Can be used to download other malware

Mark scheme

10 Max four from: 5 • A format used for storing data, for anyone to use (1) • An open-source file format can be used by both proprietary and (free and) open-source software (1) • Open source formats are often called free file formats if they are not covered by any copyrights/patents (1) • Anyone may use them at no cost (1) for any desired purpose (1) • Code is open to inspection (1) • Code can be amended without breach of copyright (1) Max three from: • Needed because not everyone can afford proprietary software (1) • Needed so users can work on files in different locations without the need for the same software (1) • Provides a standard file type (1)