Information Technology 9626/32 February/March 2023: question paper and mark scheme

Mark scheme

1(a) Four from: 4 • Increased rate of data transfer/higher bandwidth – provides faster download/more buffering capacity/less waiting for data to download – Web pages/content loads faster – due to use of higher range of frequencies – due to use of Multiple input and multiple output (MIMO) using multiple transmit/receive antenna to increase capacity/use of transmission channels – connections use (frequency/time/code) multiplex division to share – due to use of spread spectrum technology to allow multiple connections on same (set of) frequencies • Handovers between base stations are ‘smoother’/less subject to interruptions/loss of connection • Use (only) packet switching technology instead of circuit switching (as in 3G) – so IP packets can be carried/based on IP packet switched technology • Packet switching allows data/voice packets to be multiplexed/interleaved with other packets (give increased rates of data flow) 1(b) Two from: 2 • Very large capacity for connection of devices/up to a million devices per km2 • Very high bandwidth for transferring data between multiple devices • Very low latency in the connections for fast/instant responses • Seamless handover between base stations • Use of ‘beam-forming’ techniques (by base stations) to direct signal/improve connections to (specific) devices.

Mark scheme

2 Six from: 6 • Wi-Fi data transfer speeds are lower than those of cabled/wired Ethernet • Wi-Fi has a higher latency than cabled/wired Ethernet • Wi-Fi requires negotiation/recognition of connection between devices whereas cabled/wired Ethernet does not/Ethernet devices listen for/send signals onto transmission media and ‘hope’ destination device is listening/receives them • Security using Wi-Fi requires that the connection be encrypted whereas cabled/wired Ethernet does not • Connection to Wi-Fi requires user input of credentials whereas connection to cabled/wired Ethernet does not • Encrypted data in Wi-Fi signals is easier to intercept than data carried by cabled/wired/physical Ethernet connections • Wi-Fi is easier/cheaper to install than cabled/wired Ethernet which requires installation of infrastructure/cables/disturbance of existing structures • Wi-Fi can suffer from signal interference from other devices/environment whereas cabled/wired Ethernet does not • Devices using Wi-Fi can be mobile/portable/connected/disconnected easily whereas Ethernet requires devices to be physically connected.

Mark scheme

3 Six from: 6 Similarities: • Used in routers/routing devices to determine next node/router/device/hop to send data packet/datagram/frame • Algorithms create a ‘forwarding table’/routing table for use when choosing next hop/preferred route • Routing tables stored in non-volatile memory of router hardware • Both provide default route for packet if no route can be determined Differences: • Static routing tables created by network administrators whereas dynamic routing tables are created by algorithms • Static routing does not (automatically) take into account network conditions/changes whereas dynamic routing protocols create a table of routing information from real-time logical network layouts/ changes/issues/problems • Static routes are fixed whereas dynamic routing allows packets to take different routes depending on network conditions/take different routes to make more efficient use of network connections/allows as many routes as possible to be kept • Static routing tables not updated/amended when network conditions/device change whereas dynamic routing are updated/can adjust to changing network conditions • Static routing table/info does not ‘time out’ whereas dynamic routes can be time-limited/have time-to-live data/dynamic routes have a time-to-live after which the database/table will be updated • Dynamic routing changes are automatically/shared between routers/devices where static routes are not • Dynamic routing can be used to limit the number of ‘hops’ that a packet can take to its destination whereas static routing cannot. Must be 1 of each for full marks.

Mark scheme

4(a) Four from: 4 • The installation procedures to check if these are easy to follow/carry out • The start-up procedures to check if they are easy to carry out/follow/work • If the end-users can access and use the system as required • If the users find it easy to navigate/access the system/screens • The systems’ ability to (accurately) produce the required results/outputs – with frequency of errors/incorrect results/output • The structure/details/working/use of the features/functions to check if they are accessible/easy to find/use/learn • Assessment of user acceptance/satisfaction/attitudes to the use of the new system • Trouble-shooting advice/guide to check if users can make use of them/solve problems with them • The user documentation to check if it is well-structured/easy to understand/covers all the systems features. 4(b) Two from: 2 • Whether or not the new system meets the specifications set out by the analysts and designer • Whether or not the new system meets the designs • Determine if the system is working as it was designed to do and is behaving as expected • Determine if the system has any problems and how these could affect its functioning • Determine the opportunities for developers to add more features/functions in the future.

Mark scheme

5 Discuss: write about issue(s) or topic(s) in depth in a structured way. 8 Eight from: Pilot running is one department trying out/implementing the new system before implementing in all other departments. Benefits: • If the new system fails/does not work properly then only a part/section/department is affected while the others are not • Implementation is easier to manage as on smaller scale/affects less users/staff/employees at once than a full direct changeover/other methods of implementation • Staff/users/employees can be trained in small groups/by department/section • Staff/users/users/employees will/can learn from mistakes made by group using pilot system • Trained staff can assist/support training of other staff • Only one part of the company is changed over so the implementation costs can be phased over a longer period of time – which may save the company money/having to pay large sums at once/cost of complete shut down during changeover/cost of parallel running Drawbacks • Full implementation in all departments/sections of company takes a longer period of time compared to e.g., direct changeover • Can cause more disruption to company business than other methods • Support/IT staff have to support two systems at the same time unlike direct changeover • Old and new system have to interact as data is/may be exchanged between departments – so data is at risk of loss/corruption/staff have to use two systems • If the new system fails in a department/section its data may be lost/inaccessible by other departments/sections. Must be at least two of each for full marks. Max 6 marks if bullets/list of points.

Mark scheme

6 Six from: 6 • Posting of news reports/videos for public viewing at any time/anywhere • Used to reach local/specialised/targeted audiences (more quickly) with more relevant news/news can be targeted at specific/local populations • Used to reach a much wider/global audience than possible by other means • Social media is sole/only source of news for many so giving wider influence amongst different demographics • Social media accessed more often than print/TV news reporting giving more regular updates/news reports can be updated more often • Social media comments/reports can act of source of news/information/images for other news organisations • Social media news reports can be used to spread news more quickly than other media reports • Social media reports can be used to influence more people with ideas/views/opinions • Can be used to target specific audiences • Provide links to main web site/article.

Mark scheme

7(a) Two from: 2 • Hierarchical/layered/graphical description of the scope of a project/project scope to show to e.g., stakeholders/project participants/developers/management/team leaders • Describes in detail all the work required in all the stages of a project so that everyone knows what is/has to be done • Describes the planned outcomes of the project so that they can be tested/evaluated in later stages • Each layer describes all/100% of layers below/following it so that it is known what is/has been done to reach the stage. 7(b) Four from: 4 • Content/descriptions can be easily understood by all participants • Content/work can be managed/divided into manageable units – Content/work units independent/separate from each other o so work/responsibility can be assigned to individuals o so can be clearly assigned to individuals • Duration of work can be estimated/shown giving time for completion/allowing costs to be determined • Content/work is measurable allowing start/end dates/time to be estimated calculated • Content/work units can be integrated/collected together with other units to create whole project • WBS is adaptable to cope with amendments/alterations/changes to project scope.

Mark scheme

8(a) Four from: 4 • Variable is declared to store a specified condition • Switch () used to gather/hold/collect data to be tested against the variable • Use of case to enumerate/number condition/create blocks of code that could/may be executed • Variable with the condition listed for testing (against case) • Use of break to end/jump out of switch () when variable matches case/case matches variable • Use of default at end of code block to specify code to be executed if no match (by case) 8(b) Six from: 6 • Used in if/switch statements to test if conditions are true • Compare/determine the logic between (two or more) variables/values • Can be used with any data type producing a result of any data type • Can be used in a more complex manner than in other languages/valid example e.g. use of OR/|| to select from lists of variables • Represented by symbols not words (in JavaScript) • Double ‘not’/!! can be used to convert a value to Boolean data type • ‘not’ has higher precedence to ‘and’ which has higher precedence than ‘or’ in statements/’not’ is executed before ‘and’ which is executed before ‘or’ in statements • ‘and’/&& used to determine if both/all conditions are true and if so/all, are true returns true, if (any one condition) is not then it returns false • ‘or’/||/pipe symbol used to determine if one or other/either conditions are true and if so it returns true, else it returns false when both/all operands are false • ‘not’/! used to determine if values are the same/equal and if so it returns true, if not it returns false.

Mark scheme

9 Evaluate: judge the quality, importance, amount of something 8 Eight from: Pros: • Customers/clients can request/need changes – so anticipate any higher costs/decide whether or not to implement the changes • Quality/detail of specifications/requirements provided to customers/clients can be improved by examining/testing prototypes • Avoidance of potential disasters at end of project/development – as these are discovered in early prototypes rather than in final product • Discovery of problems/issues in prototypes – results in lower costs/reduced time taken for development • Prototyping requires greater customer/client involvement in development/at all stages of development – so enables clients to see/use/interact with a working model of their project – means clients are more aware/involved with development • Customers/clients can provide immediate feedback/request project changes/alter model specifications – resulting in product that more closely meets their requirements • Prototyping helps eliminate/reduce misunderstandings/miscommunications between developer and client during the development process – so end product more closely meets requirements • Prototyping can reduce project time/costs by early determination of/avoiding late changes/alterations required by client Cons: • Focus on prototyping can result in reduced/inadequate/insufficient analysis of project – which may overlook potential problems/better solutions – overlooking better solutions (due to inadequate analysis) can result in incomplete/poor specifications – which results in poorly engineered/developed final projects that are hard to maintain. • Users can confuse protypes with final products/wrongly assume that the protype is the finished product – resulting is acceptance of features that may not/will not appear in the final product/assume the final product is not properly finished/not what they expected • User may require that all proposed features of a prototype are included in the final product – resulting in team/project mission conflicts and slowed/stalled development • Prototypes take time to develop/redevelop to add/remove features – resulting in project time overrun/increased costs/missed deadlines. Must be at least two of each for full marks. Max 6 marks if bullets/list of points.

Mark scheme

10(a) Two from: 2 • (Clearly defined black/white/colour) areas in the bitmap are automatically traced (in graphics software) to create objects in the vector image • Nodes/anchors/control points are added to the objects • Object manually corrected by user to merge shapes/redefine areas/adjust borders of shapes • Colour resolution/number of bits (may be) reduced by user/software to reduce file size/more clearly define areas. 10(b) Discuss: write about issue(s) or topic(s) in depth in a structured way 6 Six from: Benefits: • Vector images are easier to edit/modify by moving/amending nodes/pathways • Editing/resizing/scaling a vector image does not affect the quality of the image/does not pixelate on enlarging/zooming into an area • Vector images can have smaller file size (for a given image size) – do not use/require as much disk space for storage – download faster than bitmap image – so can be used/displayed on low-power/small storage space devices/tablets • Edges/lines are smooth(er) in vector images/can be edited/moved without jagged/pixelated appearance – producing a higher quality image/lines Drawbacks: • Photographs do not appear realistic – because vector images/gradations of colour/surfaces are unrealistic in photographs • Small/minor drawing/editing errors/mistakes are more visible in vector images than in bitmap images – which reduces the image quality • Adding special effects is more difficult when editing vector graphics compared to bitmap images • High performance computing devices are required to carry out the calculations/recalculations when edits are made in vector images Must be at least one of each for full marks. Max 4 marks if bullets/list of points.