2023 CCEA AS-Level Digital Technology 2650 Practice Paper with Answers

1. The systems analyst investigates the existing system, gathers and analyses user requirements, and produces the system specification.
2. The project manager plans the project, allocates resources and staff, sets deadlines and monitors progress against the schedule.
3. The programmer writes, tests and debugs the program code from the design specification.
4. Time and cost are the two main factors, besides user needs, that affect systems development; either is acceptable.
Final answer: 1. investigates/analyses requirements; 2. plans/schedules the project; 3. writes/tests code; 4. time or cost.

1 mark: any valid systems-analyst task (e.g. fact-finding, requirements analysis, producing specification). 1 mark: any valid project-manager task (e.g. scheduling, resource allocation, monitoring progress). 1 mark: any valid programmer task (e.g. writing code, testing/debugging). 1 mark: 'time' or 'cost' (reject 'user needs' as it is excluded by the question). Accept other syllabus-consistent equivalents.

An IDE brings together several tools a programmer needs into one application. Typical features include: a source-code editor for writing and formatting code; a debugger for locating and stepping through errors at run time; a translator (compiler or interpreter) for converting source code into executable form; and syntax highlighting/checking, which flags syntax errors as the code is typed.
Final answer: any four of editor, debugger, translator (compiler/interpreter), syntax highlighting/checking.

1 mark for each distinct valid IDE feature named, up to 4 marks. Accept: source-code editor, debugger, compiler, interpreter, translator, syntax highlighting/checker, run-time environment for testing. Do not credit the same feature twice under different names.

1. Algorithm: a precise, ordered sequence of steps/instructions that solves a problem or completes a task.
2. Syntax: the set of rules governing the correct structure and spelling of statements in a programming language.
3. Data type: a classification that determines what kind of value (e.g. integer, real, character, string, Boolean) a piece of data can hold and what operations can be performed on it.
4. Variable: a named storage location in memory whose value can be changed while the program is running.
Final answer: as defined above for algorithm, syntax, data type and variable.

1 mark for each correct definition, up to 4. Algorithm: must convey 'ordered steps/instructions to solve a problem'. Syntax: must convey 'rules for writing valid code/statements'. Data type: must convey 'classification of kind of data/value held'. Variable: must convey 'named memory location holding a changeable value'.

1. A resource is something the project needs in order to be carried out, e.g. programmers, analysts, hardware, software licences or budget.
2. A constraint limits how the project can be run, e.g. a fixed deadline, a fixed budget, or restricted staff availability.
3. A risk is an event that could negatively affect the project, e.g. a key team member leaving, or requirements changing partway through.
4. Gantt charts (or critical path analysis) are standard project-management tools used to schedule and sequence tasks.
5. Version management is important because it keeps track of different versions of code/documents, preventing loss of work, allowing changes to be reverted and enabling several developers to work on the system without overwriting one another's work.
Final answer: 1. e.g. staff/budget; 2. e.g. fixed deadline; 3. e.g. staff leaving; 4. Gantt chart; 5. prevents lost/overwritten work and allows tracking of changes.

1 mark each for: 1. any valid resource; 2. any valid constraint; 3. any valid risk; 4. 'Gantt chart' or 'critical path analysis' (reject vague answers such as 'a plan'); 5. any valid reason referencing tracking changes / preventing lost or overwritten work / enabling collaboration.

Requirements 1, 3, 5 and 7 describe specific tasks/functions the system must perform (booking, sending reminders, viewing history, generating a report), so they are Functional (F). Requirements 2, 4, 6 and 8 describe qualities or constraints on how the system operates (response time, availability, security, usability) rather than a specific task, so they are Non-functional (NF).
(b) A functional requirement specifies what the system must do, i.e. a feature or process it must carry out, such as requirement 1 (booking, amending or cancelling an appointment). A non-functional requirement specifies a quality, standard or constraint the system must meet while performing its functions, such as requirement 2 (responding within 2 seconds) — it is not a task in itself but a condition on how tasks are carried out.
Final answer: 1F, 2NF, 3F, 4NF, 5F, 6NF, 7F, 8NF; functional = what the system does, non-functional = how well/under what constraints it does it.

1 mark for each correct classification (8 marks total): 1-F, 2-NF, 3-F, 4-NF, 5-F, 6-NF, 7-F, 8-NF. Part (b): 1 mark for a correct statement that a functional requirement describes a task/function the system must perform, with valid reference to an F item from the table; 1 mark for a correct statement that a non-functional requirement describes a quality/constraint (e.g. speed, security, availability, usability) on how the system operates, with valid reference to an NF item from the table.

(a) Processes:
1.0 Register Loan - records that a member has borrowed a book, checking the book is available and the member's account is in good standing.
2.0 Process Return - records that a borrowed book has been returned and updates its availability.
3.0 Send Overdue Reminder - checks loan due dates and generates a reminder message for any overdue books.

(b) Data stores:
D1 Member Records - holds member details, such as name, contact details and membership number.
D2 Loan Records - holds details of current and past loans, such as book, member, loan date and due date.
D3 Book Catalogue - holds details of each book title held by the library and its availability.

(c) Data flows (at least six):
1. Member details flows from Library Member to Process 1.0 Register Loan.
2. Book availability data flows from D3 Book Catalogue to Process 1.0 Register Loan.
3. New loan details flows from Process 1.0 Register Loan to D2 Loan Records.
4. Returned book details flows from Library Member to Process 2.0 Process Return.
5. Updated availability data flows from Process 2.0 Process Return to D3 Book Catalogue.
6. Due-date data flows from D2 Loan Records to Process 3.0 Send Overdue Reminder.
7. Reminder message flows from Process 3.0 Send Overdue Reminder to Library Member.
8. Loan confirmation flows from Process 1.0 Register Loan to Library Member.
Final answer: three numbered processes, three lettered data stores and at least six correctly directed data flows as listed above.

(a) 1 mark for each correctly numbered process (1.0, 2.0, 3.0) with an accurate description of its function, up to 3. (b) 1 mark for each correctly labelled data store (D1, D2, D3) with an accurate description of the data it holds, up to 3. (c) 1 mark for each distinct, correctly directed data flow between an entity/process/data store, up to 6 (accept any of the flows shown in the solution or other logically valid flows, provided direction and endpoints are both correct); do not credit flows with no stated direction or flows between two data stores (not permitted on a DFD).

(a) Alpha testing takes place within the developing organisation, usually performed by the developers or an in-house test team, before the software is released to anyone outside the company. Beta testing takes place after alpha testing, when a limited group of real, external users trials the software in their own real-world environment and reports faults back to the developer.
(b) A test plan typically records, for each test: the test data (normal, extreme and erroneous), the expected result, the actual result obtained, and the purpose/objective of the test (what feature is being checked). Any two of these are acceptable.
(c) Testing throughout development (rather than only at the end) means faults are caught close to the point where they were introduced, which makes them cheaper and easier to locate and fix, and prevents errors in one part of the system affecting other parts later in development.
Final answer: (a) alpha = in-house testing, beta = testing by real external users; (b) any two of test data/expected result/actual result/objective; (c) earlier, cheaper detection and correction of faults.

(a) 1 mark for correct description of alpha testing (in-house/by developers); 1 mark for correct description of beta testing (by real/external users before release). (b) 1 mark each for any two of: test data, expected result, actual result, test objective/description (max 2). (c) 1 mark for any valid reason, e.g. cheaper/easier to fix errors early, prevents errors propagating, ensures quality throughout.

(a) Normal test data are valid values that a user would typically enter and that the program is expected to accept and process correctly, e.g. 65. Extreme test data are valid values that lie exactly on the boundary of the accepted range, testing that the boundary itself is handled correctly, e.g. 0 or 100. Erroneous test data are invalid values that fall outside the accepted range or are of the wrong type/format, which the program should detect and reject, e.g. 150, -5 or a non-numeric entry such as 'abc'.
(b) Acceptance testing is carried out, typically by or with the end user/client, to confirm that the finished system meets the agreed requirements and performs correctly in the real working environment, before the client formally accepts (and pays for) the system.
Final answer: normal = valid typical value (e.g. 65); extreme = valid boundary value (e.g. 0 or 100); erroneous = invalid value that should be rejected (e.g. 150); acceptance testing confirms the system meets user requirements and is fit for purpose before sign-off.

(a) 1 mark each for correct explanation with a valid example of: normal data (typical valid value in range, e.g. 65); extreme data (valid value at the boundary, e.g. 0 or 100); erroneous data (invalid value outside range/wrong type, e.g. 150, -5, 'abc'). (b) 2 marks for a description that captures both: (i) checking the system meets user requirements/is fit for purpose, and (ii) that this is done by/with the user before sign-off/acceptance; 1 mark if only one element is present.

(a) Storyboarding involves producing a series of annotated sketches or mock-up screens that show what each screen of the app will look like and how the user navigates from one screen to another (e.g. from the login screen to the account-balance screen). It lets designers and users visualise and discuss the interface's layout and flow early on, and identify problems, before any programming effort is spent, saving time and cost.
(b) Prototyping a data model involves building a simplified, working draft of the proposed data structures (e.g. sample tables/fields) and showing it to the user. The user gives feedback on whether it captures the data correctly and completely, and the designer refines the model iteratively based on this feedback until it is an accurate representation of the data required by the system.
Final answer: (a) storyboard = sequence of screen sketches showing layout/navigation, reviewed with users before coding; (b) prototype data model = draft data structures shown to users and refined iteratively based on feedback.

(a) 1 mark for identifying storyboarding as a sequence of screen sketches/mock-ups; 1 mark for reference to showing navigation/flow between screens; 1 mark for reference to reviewing with users/getting feedback before coding, or identifying issues early. Max 3. (b) 1 mark for describing a prototype data model as a draft/simplified version of the data structures; 1 mark for reference to user feedback leading to refinement/iteration. Max 2.

(a) In direct changeover, the old system is stopped and the new system is started immediately in its place, with no period of overlap; this is fast and cheap but risky if the new system fails. In parallel changeover, the old and new systems operate simultaneously for a period of time, with their outputs compared/cross-checked for accuracy, and the old system is only switched off once confidence in the new system is established; this is safer but more expensive (double running costs, more staff time) and slower.
(b) Phased changeover introduces the new system module by module or function by function. Advantage: because only one part changes at a time, any faults are limited to that part, reducing overall risk and disruption. Disadvantage: it takes considerably longer overall to complete the changeover than a direct changeover, and requires the old and new systems' modules to interface with each other during the transition, which can be technically complex.
(c) Pilot changeover introduces the new system in one branch, department or site first; once it is shown to work successfully there, it is rolled out to the rest of the organisation.
Final answer: (a) direct = immediate full switch, parallel = both systems run together then old is dropped; (b) advantage = contained risk, disadvantage = takes longer overall; (c) pilot changeover.

(a) 1 mark for correct description of direct changeover (immediate, no overlap); 1 mark for correct description of parallel changeover (both run together, cross-checked, then old is dropped). (b) 1 mark for any valid advantage of phased changeover (e.g. reduced/contained risk, easier to isolate faults, easier for staff to adapt gradually); 1 mark for any valid disadvantage (e.g. takes longer overall, modules must interface with old system during transition, more complex to manage). (c) 1 mark for 'pilot' (changeover).

(a) User documentation is aimed at the end users who will operate the system day to day; it explains, in non-technical language, how to carry out tasks such as logging in, entering data or producing reports, often including screenshots and troubleshooting/FAQ sections. Technical documentation is aimed at IT/technical staff (including future programmers who may need to maintain the system); it includes material such as the system design/specification, program code with comments, data dictionaries and network/hardware configuration details, which allow the system to be understood, fixed and updated in future.
(b) Data conversion is the process, carried out during implementation, of taking the data held by the old system (which may be on paper or in an incompatible format) and converting/transferring it into the format required by the new system, so that the new system has the data it needs to operate from day one.
Final answer: user documentation supports end users (e.g. step-by-step task guide); technical documentation supports developers/maintainers (e.g. system specification or data dictionary); data conversion = transferring/reformatting old data to work with the new system.

(a) 1 mark for correct description of user documentation (aimed at end users, explains how to use the system) + 1 mark for a valid example of its content (e.g. user guide, step-by-step instructions, FAQs). 1 mark for correct description of technical documentation (aimed at technical staff, explains how the system works for maintenance) + 1 mark for a valid example (e.g. specification, code listing, data dictionary). Max 4. (b) 1 mark for correctly stating that data conversion means transferring/reformatting existing data into a format usable by the new system.

(a) Corrective maintenance fixes errors or faults discovered in the system after it has gone live, e.g. correcting a bug that causes an invoice total to be calculated incorrectly. Adaptive maintenance changes the system so it continues to work correctly when its environment changes, e.g. updating the software to run on a new version of an operating system, or to comply with a change in the law such as a new VAT rate. Perfective maintenance improves the system beyond its original specification, such as by improving performance or usability, e.g. optimising a report that has become slow to generate as data volumes have grown.
(b) The overall purpose of system maintenance is to ensure that, once implemented, the system continues to operate correctly, efficiently, securely and in line with users' changing needs, thereby extending the system's useful working life rather than requiring a costly full redevelopment.
Final answer: corrective = fixing faults (e.g. bug fix); adaptive = adjusting to a changed environment (e.g. new OS/law); perfective = improving beyond spec (e.g. speed/usability improvement); overall purpose = keep the system correct, efficient and up to date, extending its useful life.

(a) 1 mark each for a correct description with a valid example of: corrective maintenance (fixing an existing fault/bug); adaptive maintenance (changing to suit a new environment/external requirement); perfective maintenance (improving/enhancing beyond original spec). Max 3. (b) 2 marks for a full statement of purpose covering keeping the system correct/efficient/up to date and extending its useful life; 1 mark for a partial statement (e.g. only 'to fix problems').

(a) Systems design takes the requirements produced during analysis and translates them into a detailed technical plan showing exactly how the system will be built — including the design of inputs, outputs, data structures/data model, processing/algorithms and the user interface — so that programmers have a clear blueprint to develop the system from.
(b) Testing is carried out to find and remove faults/errors in the system, and to confirm that the system behaves as intended and meets the requirements identified during analysis, before it is released. This reduces the risk of faults being encountered by real users or corrupting real data once the system goes live, protecting the organisation's reputation and operations.
Final answer: (a) design converts requirements into a detailed build plan (inputs/outputs/data/processes/interface); (b) testing finds/removes faults and confirms the system meets requirements before release, protecting users and data.

(a) 1 mark for reference to turning requirements/analysis into a detailed plan; 1 mark for naming at least one design element (inputs, outputs, data structures, processing, user interface). Max 2. (b) 1 mark for reference to finding/removing errors; 1 mark for reference to confirming the system meets requirements or protecting users/data once live. Max 2.

(a) Data conversion is necessary because the data held by the old system (which may be on paper, in a different file format, or structured differently) is very unlikely to be directly compatible with the new system's data structures. Converting it ensures the new system has access to complete, correctly formatted historical data from the moment it goes live, rather than the organisation having to start with no data at all.
(b) If data conversion is carried out poorly, data can be lost, corrupted, duplicated or incorrectly mapped between the old and new formats. This means the new system could begin operation with inaccurate or incomplete records, which could lead to poor decisions being made or errors affecting customers (e.g. an incorrect account balance).
Final answer: (a) conversion is needed because old data is not directly compatible with the new system's format/structure; (b) risk = data loss, corruption or duplication leading to inaccurate/incomplete records in the new system.

(a) 1 mark for stating old data is in an incompatible format/structure; 1 mark for stating conversion allows the new system to use/process it correctly (i.e. avoids starting with no data). Max 2. (b) 2 marks for a clear, specific risk (e.g. data loss/corruption/duplication leading to inaccurate or incomplete records); 1 mark for a vague answer (e.g. just 'errors').

(a) Trace with a=4, b=9, c=6: line 2 sets max = a = 4. Line 3: is b (9) > max (4)? Yes, true, so line 4 runs; but line 4 sets max = a, so max stays at 4. After line 5, max = 4. Line 6: is c (6) > max (4)? Yes, true, so line 7 runs, setting max = c = 6. After line 8, max = 6. Line 9 outputs 6.
(b) The true largest of 4, 9 and 6 is 9, but the algorithm outputs 6 — an incorrect result. This happens because line 4 incorrectly assigns max = a when it should assign max = b; the condition on line 3 correctly detects that b is bigger than the current max, but the assignment on line 4 fails to actually store b's value, so the larger value of b is lost.
(c) Changing line 4 to 'max = b' fixes the error: re-tracing, after line 5 max would correctly become 9 (since b=9>4), and after line 8, c=6 is not > 9, so max remains 9, and the algorithm would correctly output 9.
Final answer: (a) max after line 5 = 4, max after line 8 = 6, output = 6; (b) line 4 wrongly assigns max = a instead of max = b; (c) corrected line: max = b.

(a) 1 mark for max = 4 after line 5; 1 mark for max = 6 after line 8; 1 mark for stating the final output is 6. Error-carried-forward applies if an arithmetic/tracing slip is made consistently. (b) 1 mark for correctly identifying that line 4 assigns 'max = a' (should be 'max = b'); 1 mark for explaining that this means the larger value of b is never stored/is lost, giving the wrong (too small) result. (c) 2 marks for the correct line 'max = b' (or equivalent correct pseudocode); 1 mark if the general idea is right but syntax/variable name is imprecise.

Direct changeover would switch the call-centre staff onto the new system immediately, with the old system withdrawn at the same time. This is the cheapest and quickest option, requiring no double running costs, but it is very high risk for this organisation: if the new claims-processing system has an undetected fault, staff would have no working fallback system, causing the very downtime, lost income and customer dissatisfaction the company is trying to avoid.

Parallel changeover would run the old and new claims-processing systems side by side for a period, with staff (or the system) cross-checking that both produce the same results for the same claims. If the new system fails or produces incorrect output, staff can continue working on the trusted old system with no loss of service, which directly protects availability and customer satisfaction. The drawback is that parallel running is more expensive (staff must effectively do the work twice, or maintain two systems/licences) and takes longer before the old system can finally be retired.

For this insurance company, where continuous availability and accuracy of claims processing are critical to income and customer trust, the benefit of having a safe fallback outweighs the extra cost and time of parallel running. Direct changeover's speed and low cost are less important here than avoiding a scenario in which the company has no working system at all.
Final answer: parallel changeover is recommended, because it eliminates the risk of a period with no working system, which is essential given the company's need for continuous call-centre availability, even though it costs more and takes longer than direct changeover.

Level 3 (6-7 marks): Accurate, detailed description of both direct and parallel changeover; explicit evaluation that links each method's advantages/disadvantages to the company's specific context (continuous availability, cost of downtime); clear justified recommendation; precise technical terminology; high standard of written communication.
Level 2 (3-5 marks): Correct description of both changeover methods; some evaluation/comparison, but limited or generic contextual justification; a recommendation is given; mostly clear terminology and expression.
Level 1 (1-2 marks): Description of only one changeover method, or a superficial/generic treatment of both with little evaluation or no clear recommendation; minimal use of technical terminology.
0 marks: No creditable response.

The waterfall model develops a system through a strict sequence of stages (analysis, design, implementation, testing), with each stage completed and signed off before the next begins. Its main strength is that it is well structured, easy to manage and document, and works well when requirements are stable and fully understood from the outset. However, it assumes requirements do not change once analysis is complete; going back to an earlier stage to accommodate a change is difficult and costly, which is a serious weakness for this banking app, since the client's requirements are expected to evolve as users try the app.

Agile develops the system through short, repeated cycles (iterations/sprints), each producing a small working piece of the app that is reviewed with the client/users, whose feedback shapes the next iteration. This makes Agile well suited to projects where requirements are uncertain or likely to change, as here, since new or changed requirements can be incorporated into a future iteration rather than requiring a costly restart. Its main weaknesses are that it can be harder to produce fixed, complete documentation and to give the client an accurate fixed cost/timescale at the outset, since the full scope may not be known until later iterations.

Given that the client's requirements for the banking app are not yet fixed and are expected to change based on user feedback, Agile's flexibility and continuous feedback loop make it clearly more suitable than the waterfall model's rigid, sequential structure, even though it may make the overall cost and timescale less predictable at the start.
Final answer: Agile is recommended over the waterfall model, because its iterative, feedback-driven cycles can absorb the app's evolving requirements, which the waterfall model's fixed, sequential stages cannot easily accommodate.

Level 3 (6-7 marks): Accurate, detailed description of both the waterfall model and Agile; explicit evaluation linking each approach's strengths/weaknesses to the changing-requirements context of the app; clear justified recommendation; precise technical terminology; high standard of written communication.
Level 2 (3-5 marks): Correct description of both approaches; some evaluation/comparison but limited contextual justification; a recommendation is given; mostly clear terminology and expression.
Level 1 (1-2 marks): Description of only one approach, or a superficial/generic treatment with little evaluation or no clear recommendation; minimal technical terminology.
0 marks: No creditable response.

In an object-oriented approach, each vehicle in the simulation would be represented as an object: a self-contained unit combining data (attributes, such as registration number and current location) and the methods (procedures) that act on that data (such as calculateJourneyTime() or updateLocation()). A general Vehicle class could define the attributes and methods common to all vehicles. More specific classes, Car, Van and Truck, could then inherit from the Vehicle class, automatically gaining its shared attributes and methods, while adding their own extra attributes and methods, such as a maxLoadCapacity attribute and a checkOverload() method that only apply to Truck. Inheritance therefore avoids rewriting the shared code three times, and encapsulation (bundling each vehicle's data with the methods that use it) makes it clear which code is responsible for which object, reducing the chance of one part of the program accidentally interfering with another's data.

A procedural (non-object-oriented) approach would instead store vehicle data in separate variables or arrays/records and write separate functions to operate on cars, vans and trucks. Because there is no inheritance mechanism, shared behaviour (e.g. updating location) would typically need to be written once for each vehicle type, or handled with more complex conditional logic (e.g. IF vehicleType = 'truck' THEN...) scattered through the program, which is more repetitive, harder to extend (e.g. if a new vehicle type, such as a motorbike, is added) and more error-prone to maintain, since a change to shared behaviour must be found and updated in multiple places.

For this fleet simulation, where vehicle types clearly share a common set of features but also need their own specialised behaviour, the object-oriented approach's use of classes and inheritance is better suited than the procedural approach, since it models the real-world relationship between vehicle types directly, reduces code duplication and makes the system easier to extend with new vehicle types in future.
Final answer: the object-oriented approach is recommended over a procedural approach, because classes, objects, methods and inheritance let Car, Van and Truck share common Vehicle code while each still defining its own specialised behaviour, giving less duplicated and more maintainable/extensible code than the procedural alternative.

Level 3 (7-8 marks): Accurate, detailed description of the object-oriented approach using all four required terms (objects, classes, methods, inheritance) correctly applied to the vehicle-fleet scenario; explicit, well-justified evaluation/comparison against a procedural approach; clear conclusion; precise technical terminology; high standard of written communication.
Level 2 (4-6 marks): Correct description of the object-oriented approach using most of the required terms correctly; some comparison with a procedural approach, but with limited or generic justification; a conclusion is present; mostly clear terminology and expression.
Level 1 (1-3 marks): Superficial or partial description of the object-oriented approach, using few of the required terms correctly, and/or little or no comparison with a procedural approach; minimal technical terminology.
0 marks: No creditable response.

(a) The number of different values representable with n bits is given by \( 2^n \).
(b) With n = 6: \( 2^6 = 64 \), so 64 different values can be represented using 6 bits.
(c) 1 kilobyte = 1024 bytes, so 4 kilobytes = \( 4 \times 1024 = 4096 \) bytes.
Final answer: (a) \( 2^n \); (b) 64; (c) 4096 bytes.

(a) 1 mark for \( 2^n \). (b) 1 mark for the correct value 64, with working shown (\( 2^6 = 64 \)); error-carried-forward allowed if (a) is wrong but applied correctly. (c) 1 mark for 4096 (accept correct working \( 4 \times 1024 \) even if final arithmetic slip, per ECF).

Using place values \( 128, 64, 32, 16, 8, 4, 2, 1 \):
173 - 128 = 45, so bit 128 = 1.
45 - 64: too small, so bit 64 = 0.
45 - 32 = 13, so bit 32 = 1.
13 - 16: too small, so bit 16 = 0.
13 - 8 = 5, so bit 8 = 1.
5 - 4 = 1, so bit 4 = 1.
1 - 2: too small, so bit 2 = 0.
1 - 1 = 0, so bit 1 = 1.
This gives \( 10101101 \). Check: \( 128+32+8+4+1 = 173 \). Correct.
Final answer: \( 173 = 10101101_2 \).

1 mark for correct method (place-value/repeated subtraction) shown. 1 mark for correct binary digits derived. 1 mark for the final 8-bit answer 10101101 (must be exactly 8 bits, leading zeros included). ECF: if working shows one place-value slip but is applied consistently, allow marks for method and consistent digits, but not for the final answer mark unless it equals 10101101.

The leading bit is 1, so the number is negative. To find its magnitude: invert all the bits, then add 1.
Invert 11101011: 00010100.
Add 1: 00010100 + 1 = 00010101.
Convert 00010101 to denary: \( 16 + 4 + 1 = 21 \).
Since the original leading bit was 1, the value is negative: \( -21 \).
Check: 21 in 8-bit binary is 00010101; inverting gives 11101010, adding 1 gives 11101011, which matches the original number, confirming -21 is correct.
Final answer: \( 11101011_2 = -21 \).

1 mark for correctly inverting the bits (00010100). 1 mark for correctly adding 1 to get the magnitude in binary (00010101) or its denary equivalent (21). 1 mark for the correct final signed answer, -21 (must include the negative sign). ECF applies if a single bit-inversion slip is carried through consistently but the final numeric answer mark requires -21 exactly.

(a) An 8-bit code can represent \( 2^8 = 256 \) different values, so extended ASCII can represent 256 different characters.
(b) ASCII (particularly standard 7-bit ASCII) can only represent a limited character set, largely the Latin alphabet, digits and basic symbols. Unicode uses more bits and can represent a vastly larger number of characters, including those needed for many different world languages/scripts and symbols, which ASCII cannot represent.
Final answer: (a) 256; (b) Unicode supports far more characters/scripts (e.g. non-Latin languages) than ASCII can.

(a) 1 mark for 256 (accept working \( 2^8 \)). (b) 1 mark for any valid advantage, e.g. supports more characters/a much larger character set, or supports multiple languages/non-Latin scripts, that ASCII does not support.

1 megabyte = 1024 kilobytes, so 6 megabytes = \( 6 \times 1024 = 6144 \) kilobytes.
Final answer: 6144 KB.

1 mark for correct method shown (\( 6 \times 1024 \)). 1 mark for the correct final answer, 6144 KB.

(a) Multiply each digit by its weight:
4 x 7 = 28
3 x 6 = 18
9 x 5 = 45
1 x 4 = 4
7 x 3 = 21
2 x 2 = 4
Sum = 28 + 18 + 45 + 4 + 21 + 4 = 120.
Divide by 11: \( 120 \div 11 = 10 \) remainder \( 10 \) (since \( 11 \times 10 = 110 \), and \( 120 - 110 = 10 \)).
Check digit = 11 - 10 = 1.
Final check digit = 1, so the full code including check digit is 4391721.
(b) A check digit is designed to catch transcription errors such as a single mistyped digit, or transposition errors where two adjacent digits are swapped (e.g. entering 4931 72 instead of 4391 72), since these would normally produce a different weighted sum and therefore a different, mismatching check digit.
(c) A limitation is that a check digit can only signal that an error is present (the entered check digit does not match the calculated one); it cannot say which digit is wrong or what the correct value should be, and it is not guaranteed to catch every possible error (for example, certain combinations of compensating errors could coincidentally still produce a matching check digit).
Final answer: (a) check digit = 1; (b) transposition error or mis-keyed digit; (c) it detects but does not locate/correct an error, and cannot guarantee detection of every possible error.

(a) 1 mark for correctly multiplying all six digits by their weights (28, 18, 45, 4, 21, 4); 1 mark for the correct total, 120; 1 mark for correctly finding the remainder on division by 11 (remainder 10); 1 mark for the correct final check digit, 1 (= 11 - 10). ECF applies throughout if an early arithmetic slip is carried through consistently. (b) 1 mark for any valid error type, e.g. transposition error, single mis-keyed/mistyped digit. (c) 1 mark for any valid limitation, e.g. detects but does not correct/locate the error, or cannot guarantee all errors (e.g. compensating errors) are detected.

(a) The processor (CPU) is the component that carries out the fetch-execute cycle, fetching, decoding and executing the instructions that make up a program.
(b) Cache memory is a small amount of very fast memory, located close to (or within) the processor, used to store data and instructions that have been recently or frequently used, so the processor can access them more quickly than fetching them from main memory each time.
(c) The address bus carries the memory address that the processor wants to read from or write to, so it specifies the location in memory involved in a data transfer (it does not carry the data itself).
(d) An I/O controller manages the transfer of data between the processor/memory and a connected input or output device (such as a keyboard, printer or storage device), handling the details of that communication so the processor does not have to.
Final answer: (a) executes program instructions; (b) fast memory for frequently used data, speeding access; (c) carries addresses between processor and memory; (d) manages data transfer with an I/O device.

1 mark for each correct description, up to 4: (a) reference to fetching/executing program instructions; (b) reference to fast, small memory storing frequently/recently used data to speed up processor access; (c) reference to carrying memory addresses (not data) between processor and memory; (d) reference to managing/handling data transfer between processor and an input/output device.

(a) In the fetch-execute cycle, the processor fetches the next instruction from main memory (using the address held in a register), decodes the instruction to work out what operation is required, and then executes that operation (which may involve reading/writing data). The processor then repeats this cycle for the next instruction, continuing for as long as the program runs.
(b) The speed of processing can be influenced by the processor type (its architecture/design, including features such as the number of cores) and the clock speed (the rate, measured in Hz, at which the processor carries out fetch-execute cycles) — a higher clock speed and a more capable processor architecture generally allow more instructions to be processed per second.
Final answer: (a) fetch instruction from memory, decode it, execute it, repeat; (b) processor type and clock speed.

(a) 1 mark for reference to fetching the instruction from memory and decoding it; 1 mark for reference to executing the instruction and the cycle repeating. Max 2. (b) 1 mark for 'processor type' (or architecture/number of cores); 1 mark for 'clock speed'. Max 2.

(a) The operating system is system software that manages the computer's hardware resources (such as the processor, memory, storage devices and peripherals), runs and manages application programs, and provides a user interface, acting as an intermediary between the user/applications and the underlying hardware.
(b) A multi-user operating system is designed to allow several different users to access and use the same computer system, typically at the same time, e.g. via separate terminals connected to a central server. A multitasking operating system is designed to allow a single user to have several different programs or tasks open and apparently running at the same time on one device (e.g. browsing the web while playing music), by rapidly switching the processor's attention between them.
Final answer: (a) manages hardware/software resources and provides an interface between user and hardware; (b) multi-user = supports several separate users on one system, multitasking = one user running several programs at once.

(a) 1 mark for reference to managing hardware/software resources; 1 mark for reference to providing an interface between user/applications and hardware. Max 2. (b) 1 mark for correct description of multi-user (multiple users share access to one system); 1 mark for correct description of multitasking (one user runs multiple programs/tasks concurrently). Max 2.

(a) Generic software is designed to be flexible and useful for a wide variety of general tasks across many different users and organisations, such as a word processor or spreadsheet package, which can be applied to many different jobs. Special-purpose software is designed and written to carry out one particular task, or a narrow, specific set of related tasks, for a particular type of user, such as payroll software (used specifically to calculate staff wages) or software controlling a specific machine.
(b) Off-the-shelf software is developed once and sold to many customers, so its development cost is spread across all of those customers, making it considerably cheaper to buy than paying for bespoke development; it is also usually available to buy and use immediately, without waiting for custom development, and has typically already been tested by many other users.
Final answer: (a) generic = flexible, general-purpose (e.g. word processor); special-purpose = designed for one specific task (e.g. payroll software); (b) off-the-shelf is cheaper (shared development cost) and available immediately.

(a) 1 mark for a correct distinction (generic = general/flexible/wide use; special-purpose = one specific task/narrow use) with 1 mark for a valid example of each (e.g. word processor vs payroll software) — award up to 2 total for a complete, correctly exemplified answer. (b) 2 marks for a clear advantage referencing lower cost and/or faster availability (accept 'already tested by many users' as an alternative valid point); 1 mark for a vaguer/partial answer.

(a) A URL (Uniform Resource Locator) is the address that specifies the location of a specific resource (e.g. a web page or file) on the internet, and how to access it.
(b) HTTP (Hypertext Transfer Protocol) is the protocol/set of rules that governs how web pages and other data are requested and transferred between a web browser (client) and a web server.
(c) An ISP (internet service provider) is a company that provides individuals or organisations with a connection to, and access to, the internet, usually for a subscription fee.
(d) A browser cache is a temporary local storage area on a user's device that keeps copies of recently visited web pages, images and other files, so that if the same page/resource is requested again, it can be loaded more quickly from the local cache rather than being downloaded again from the web server.
Final answer: (a) address locating a web resource; (b) protocol for transferring web pages/data between browser and server; (c) company providing internet access; (d) temporary local store of web pages/files for faster reloading.

1 mark for each correct definition, up to 4: (a) must convey 'address that locates a resource/page on the web'; (b) must convey 'protocol for transferring web pages/data between browser and server'; (c) must convey 'company/organisation providing internet access'; (d) must convey 'temporary local storage of web content to speed up future loading'.

(a) Domain names are structured hierarchically, with each part (separated by full stops) narrowing down from the most general level (on the right) to the most specific (on the left). In 'www.ccea.org.uk': 'uk' is the country-code top-level domain (indicating the United Kingdom); 'org' is the second-level domain indicating the type of organisation (a non-commercial/organisational body); 'ccea' identifies the specific organisation; and 'www' identifies the particular host/web server within ccea.org.uk's domain.
(b) An intranet uses the same underlying web technology as the internet but is a private network, typically accessible only to an organisation's own staff (often via a username/password or from within the organisation's own network). This means sensitive internal information (e.g. staff records, internal documents) can be shared and accessed only by authorised staff, giving greater security and control than publishing the same material on the public internet, where it could potentially be accessed by anyone.
Final answer: (a) hierarchical, right-to-left: uk = country-code top-level domain, org = organisation type, ccea = organisation name, www = host; (b) intranet is private/restricted to staff, giving greater security/control over internal information than the public internet.

(a) 1 mark for describing the hierarchical/right-to-left structure of domain names; 1 mark for correctly identifying at least two of the components of 'www.ccea.org.uk' (e.g. uk = country code, org = organisation type, ccea = organisation name). Max 2. (b) 2 marks for a benefit clearly linked to the intranet being private/access-restricted, improving security/control of internal information; 1 mark for a vaguer answer (e.g. just 'it is more secure' with no reason).

(a) The anchor tag () is used to create a hyperlink, allowing a user to click through from one web page to another page, resource or location. The unordered-list tag (

) is used to create a bulleted list (a list of items with no inherent order, each usually marked with a bullet point), as opposed to a numbered list.
(b) CSS (cascading style sheet) is used to control the visual presentation of a web page — such as fonts, colours, spacing and layout — separately from the HTML, which defines the page's content and structure. Because a single CSS file can be linked to many HTML pages, a website's styling can be defined once and applied consistently across the whole site, and updated in one place rather than editing every page individually.
Final answer: (a) anchor tag = creates a hyperlink; unordered-list tag = creates a bulleted list; (b) CSS separates presentation/styling from content and can be applied consistently across multiple pages from one file.

(a) 1 mark for correct purpose of the anchor tag (creates a hyperlink/link); 1 mark for correct purpose of the unordered-list tag (creates a bulleted/non-numbered list). Max 2. (b) 1 mark for reference to CSS controlling presentation/styling (fonts, colours, layout) separately from content; 1 mark for reference to consistent/reusable styling across multiple pages from one file. Max 2.

(a) Client-side processing is carried out by the user's own web browser/device, using code (such as JavaScript) that is downloaded and run locally, for example validating that a form has been filled in correctly before it is submitted. Server-side processing is carried out on the remote web server, for example running code that queries a database and generates the resulting web page's content, before sending the finished page to the browser.
(b) Methods used to help secure data sent over the internet include: encryption (scrambling data, including the use of public and private keys, so it cannot be read if intercepted); HTTPS (the secure version of HTTP); SSL (Secure Sockets Layer, which encrypts the connection between browser and server); and digital signatures/digital certificates (which verify the identity of a website/sender and that data has not been tampered with). Any two of these are acceptable.
Final answer: (a) client-side = processing done in the user's browser/device; server-side = processing done on the web server; (b) any two of encryption, HTTPS, SSL, digital signature/certificate.

(a) 1 mark for correct description of client-side processing (occurs on the user's device/browser); 1 mark for correct description of server-side processing (occurs on the web server). Max 2. (b) 1 mark each for any two of: encryption (including public/private key), HTTPS, SSL, digital signature/digital certificate. Max 2.

(a) In batch processing, transactions or jobs are collected together over a period of time and then processed together, as a single batch, usually when the computer is otherwise free (e.g. overnight); there is no requirement for an immediate response to any individual transaction. In real-time processing, each transaction is processed individually and immediately as it arrives, with the system responding straight away, so that its output can affect what happens next without any noticeable delay.
(b) An ATM uses real-time processing. This is because a customer is standing at the machine waiting for an immediate response — the transaction (e.g. a cash withdrawal) must be validated, the customer's balance checked and updated, and the cash dispensed, all within a few seconds, which batch processing (with its delayed, grouped processing) could not provide.
(c) A POS terminal produces outputs such as a printed receipt for the customer, and/or an updated stock-level record (reducing stock by the quantity sold) sent to the stock-control system.
Final answer: (a) batch = grouped, delayed processing with no immediate response; real-time = immediate individual processing with an immediate response; (b) ATMs use real-time processing, because the customer needs an immediate response; (c) e.g. a printed receipt.

(a) 1 mark for correct description of batch processing (transactions grouped and processed together, later/no immediate response needed); 1 mark for correct description of real-time processing (each transaction processed immediately, immediate response). Max 2. (b) 1 mark for correctly identifying 'real-time processing'; 1 mark for valid justification referencing the need for an immediate response/customer waiting. Max 2. (c) 1 mark for any valid POS output, e.g. printed receipt, updated stock record/stock level.

(a) Data is a raw, unprocessed fact with no context on its own: the reading '18' is data, since alone it has no meaning (18 what? compared to what?). Information is data that has been processed or given context so that it becomes meaningful: 'temperatures are rising across the region' is information, since it results from comparing/interpreting several individual readings. Knowledge is the understanding gained by applying experience, expertise or judgement to information: 'a storm is likely within 48 hours' is knowledge, because it results from the meteorologist applying professional experience/expertise to the information to reach a conclusion/prediction.
(b) Besides accuracy, the quality of information can be affected by: relevance (whether the information is actually useful for the purpose intended); how up to date it is (currency); completeness (whether all necessary information is present); its presentation (whether it is presented clearly/appropriately for the audience); and its reliability (whether the source/method of collection can be trusted). Any two of these are acceptable.
Final answer: (a) data = '18'; information = 'temperatures are rising across the region'; knowledge = 'a storm is likely within 48 hours'; (b) any two of relevance, currency (up to date), completeness, presentation, reliability.

(a) 1 mark each for correctly identifying the data, information and knowledge elements of the scenario (max 3); accept answers that correctly explain why each is classified as such even if the exact quoted phrase differs slightly. (b) 1 mark each for any two of: relevance, up-to-date/currency, completeness, presentation, reliability (max 2; do not credit 'accuracy' again as it is excluded by the question).

i. 31 February does not exist as a valid calendar date, so this would typically be rejected by a format check (the date does not match a valid date pattern/does not exist).
ii. 150 falls outside the accepted range of 0 to 100, so this is detected by a range check.
iii. 'BT' alone is too short to be a valid UK postcode, so this is detected by a length check.
(b) A key limitation of data validation is that it can only check whether data is reasonable, sensible or in the correct format/range — it cannot check whether the data is actually true or correct. For example, a range check would accept a plausible but incorrect date of birth, as long as it fell within a sensible range.
(c) Double-entry verification requires the same data to be entered twice (e.g. independently by two different operators, or twice by the same operator), after which the two entries are compared automatically; if they do not match, an error is flagged, helping to catch data-entry mistakes such as mistyped characters.
Final answer: i. format check; ii. range check; iii. length check; (b) validation cannot confirm data is actually true/correct, only that it is reasonable in form; (c) double-entry verification compares two independent entries of the same data to catch entry errors.

(a) 1 mark each for: i. format check (accept 'type check' or reference to invalid/non-existent date); ii. range check; iii. length check. Max 3. (b) 1 mark for any valid limitation, e.g. validation cannot guarantee data is true/accurate, only that it is reasonable/in the correct format or range. (c) 1 mark for a description that data is entered twice (independently) and compared, to catch entry errors.

(a) A batch total is calculated by adding together a numeric field (e.g. total hours worked, a 'hash' total with no real-world meaning of its own) or counting the number of records across a whole batch of timesheets, both before the batch is entered and again after entry (or during processing). If the total calculated after entry does not match the total calculated before entry, this indicates that at least one record in the batch has been entered incorrectly, omitted, or entered twice, prompting a recheck of the batch.
(b) Data validation is an automatic check, carried out by the software itself, that data entered is reasonable, sensible and in the correct format/range — for example, the payroll system automatically checking that the 'hours worked' entered for an employee falls within a sensible range, such as 0 to 60 hours. Data verification is a check, which may be manual or involve repeated entry, that the data entered exactly matches the original source data — for example, a supervisor proofreading the entered timesheet figures against the original paper timesheets, or the hours being keyed in twice (by the same or different staff) with the two entries compared for an exact match. The key difference is that validation checks data is 'sensible', while verification checks data is 'correct/matches its source'.
Final answer: (a) batch total = a sum/count calculated before and after entry of a batch, used to detect missing, duplicated or mis-entered records if the totals do not match; (b) validation = automatic system check that data is reasonable (e.g. hours in range 0-60); verification = check that entered data matches the original source (e.g. proofreading against paper timesheets, or double entry).

(a) 1 mark for describing a batch total as a sum/count calculated over a batch of records; 1 mark for explaining that a mismatch between the before/after (or expected/actual) totals indicates an error (e.g. missing, duplicated or mis-entered record). Max 2. (b) 1 mark for a correct description of validation (automatic, checks data is reasonable/in correct format or range) + 1 mark for a valid payroll example; 1 mark for a correct description of verification (checks entered data matches the original source, e.g. proofreading or double entry) + 1 mark for a valid payroll example. Max 4.

ASCII (American Standard Code for Information Interchange) traditionally uses 7 or 8 bits per character, giving at most 256 possible characters. This is enough to represent the English alphabet (upper and lower case), digits and common symbols, and ASCII files are small and simple. However, ASCII's character set is far too small to represent the thousands of unique characters used in Mandarin Chinese, or the distinct letterforms and joining rules of the Arabic script; text in these languages simply could not be correctly represented using standard ASCII.

Unicode uses a much larger number of bits per character (allowing many more possible code points), so it can represent characters from virtually every writing system in use worldwide, including the many thousands of Chinese characters and the full Arabic alphabet, as well as English. This makes it possible for a single Unicode-encoded message to correctly mix English, Chinese and Arabic text, which is essential for an international messaging app. The main drawback of Unicode is that it typically requires more storage space (more bits) per character than ASCII, and processing/rendering some scripts (e.g. right-to-left Arabic text) can be more complex.

Since the app must correctly support English, Mandarin Chinese and Arabic text, ASCII is not a viable option at all, as it cannot represent most of the required characters. Unicode is essential here, despite its larger storage requirement, because supporting all three languages correctly is a fundamental requirement of the app.
Final answer: Unicode is recommended, since it can represent the characters needed for English, Mandarin Chinese and Arabic, whereas ASCII's small character set cannot support Chinese or Arabic text at all.

Level 3 (6-7 marks): Accurate, detailed description of both ASCII and Unicode (including reference to character-set size/number of bits); explicit evaluation linking each encoding's capabilities to the specific multi-language requirement of the app; clear justified recommendation; precise technical terminology; high standard of written communication.
Level 2 (3-5 marks): Correct description of both ASCII and Unicode; some evaluation/comparison, but limited or generic contextual justification; a recommendation is given; mostly clear terminology and expression.
Level 1 (1-2 marks): Description of only one encoding system, or a superficial/generic treatment of both with little evaluation or no clear recommendation; minimal technical terminology.
0 marks: No creditable response.

A bitmap (BMP) file typically stores an image's data uncompressed, recording the colour value of every individual pixel exactly. This means bitmap images can offer very high, exact image quality, with no loss of detail. However, because no compression is applied, bitmap files are usually very large, especially for a high-resolution photograph, which means they take a long time to download over a mobile data connection, use more of a visitor's data allowance, and take up more storage space on the website's server.

JPEG (Joint Photographic Experts Group) format applies compression to reduce file size, which is particularly effective for photographic images with many gradual colour changes. JPEG typically uses lossy compression, discarding some image detail that is not easily noticed by the human eye, which can achieve a much smaller file size than an equivalent bitmap for only a small, often barely visible, reduction in image quality. The trade-off is that at very high compression levels, JPEG images can show visible quality loss (e.g. blurring or blocky artefacts), and repeatedly re-saving a JPEG can gradually reduce quality further.

For this website, where fast loading over mobile data connections is a priority, JPEG's much smaller file size is a decisive advantage over bitmap's larger, uncompressed files, and JPEG's image quality (used at a sensible compression level) is more than adequate for viewing photographs on a website. Bitmap's advantage of exact, uncompressed quality is not essential here and is outweighed by its impractically large file size for this use case.
Final answer: JPEG is recommended over bitmap, because its compression gives much smaller file sizes that load faster on mobile data connections, while still providing image quality that is more than adequate for website viewing.

Level 3 (6-7 marks): Accurate, detailed description of both JPEG and bitmap formats, with explicit reference to compression, file size and image quality; evaluation clearly linked to the mobile-loading-speed context; clear justified recommendation; precise technical terminology; high standard of written communication.
Level 2 (3-5 marks): Correct description of both formats; some evaluation/comparison of file size and/or quality, but limited contextual justification; a recommendation is given; mostly clear terminology and expression.
Level 1 (1-2 marks): Description of only one format, or a superficial/generic treatment with little evaluation or no clear recommendation; minimal technical terminology.
0 marks: No creditable response.

Installing off-the-shelf software directly onto each office computer usually involves paying a one-off licence fee (or fee per computer/user), after which the software can be used without needing an internet connection. However, it must be individually installed and manually updated on every computer it runs on, which is time-consuming for a business with several machines, and the software can typically only be accessed from those specific installed computers, not remotely from elsewhere (e.g. from home or while travelling).

Accessing the accounting software as a web-based (cloud) application means the software itself runs on the provider's remote server, and users interact with it through a standard web browser. This means it can generally be accessed from any device with a browser and an internet connection, including from home, on the move or from a different office, which offers much greater accessibility for a small business whose staff may need to check accounts outside the main office. Maintenance (bug fixes, feature updates) is handled centrally by the provider on their server, so the business never needs to manually install updates on each machine. The main drawbacks are that cloud software is usually paid for through an ongoing subscription (which can cost more over a long period than a one-off licence), and it is unusable without a working internet connection, which could disrupt work if the connection fails.

For this small business, the web-based option's much greater accessibility (staff can check accounts from anywhere) and reduced maintenance burden (no manual updates needed on each computer) are likely to outweigh the drawback of an ongoing subscription cost and a dependence on internet connectivity, especially as a small business benefits from not needing dedicated IT staff to manage installed software across multiple machines.
Final answer: the web-based (cloud) deployment option is recommended, because of its greater accessibility from any location/device and lower maintenance burden (centrally updated), despite its ongoing subscription cost and reliance on an internet connection, compared with installed off-the-shelf software.

Level 3 (7-8 marks): Accurate, detailed description of both deployment options; explicit, well-justified evaluation covering all three of cost, accessibility and maintenance, applied to the small-business context; clear conclusion; precise technical terminology; high standard of written communication.
Level 2 (4-6 marks): Correct description of both options; evaluation covers at least two of cost/accessibility/maintenance but with limited or generic justification; a conclusion is present; mostly clear terminology and expression.
Level 1 (1-3 marks): Description of only one deployment option, or superficial treatment covering at most one of cost/accessibility/maintenance, with little evaluation or no clear conclusion; minimal technical terminology.
0 marks: No creditable response.