Create and interpret flowcharts

Cambridge IGCSE/A‑Level IT (9626) – Complete Syllabus Notes (2025‑27)

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1. Syllabus Checklist – AS‑Level (Topics 1‑11)

Topic No.	Title (AS 1‑11)	Key Sub‑points (exact wording from Cambridge specification)	Covered in These Notes?
1	Data Processing	Binary system – bits, bytes, kilobytes, megabytes, gigabytes Data types – numeric, alphanumeric, multimedia Storage hierarchy – primary, secondary, tertiary Fetch‑decode‑execute cycle Conversion between decimal, binary, hexadecimal Calculate storage requirements (e.g., image size, text file)	✓
2	Hardware	CPU – ALU, control unit, registers, cache Memory – RAM, ROM, cache, virtual memory Input devices – keyboard, mouse, scanner, touch screen, sensor types (temperature, pressure, proximity) Output devices – monitor, printer, speaker, actuator types (motors, solenoids, relays) Bus architecture – system bus, address bus, data bus Peripheral connections – USB, HDMI, Bluetooth, Wi‑Fi, PCI‑e	✓
3	Software & Operating Systems	System software vs application software OS functions – process management, memory management, file system, security, device drivers Utility programmes – backup, disk‑defragment, antivirus, compression Comparison of Windows, macOS, Linux (licensing, UI, security)	✓
4	Algorithms & Flowcharts	Algorithm properties – clarity, efficiency, correctness, finiteness Pseudocode – standard operators, structures, indentation Flowchart symbols – start/end, process, input/output, decision, connector, loop cue Design techniques – top‑down decomposition, modularisation, use of sub‑routines Interpretation – tracing, testing with sample data, identifying errors	✓
5	Spreadsheets	Cell references – relative, absolute, mixed Built‑in functions – SUM, AVERAGE, COUNT, IF, VLOOKUP, HLOOKUP, DATE, TEXT Data validation – list, range, custom formula Conditional formatting – colour rules, icon sets Chart types – column, line, pie, scatter, radar Basic macro recording – record, edit, assign to button	✓
6	Databases & File Concepts	Relational model – tables, fields, records, primary & foreign keys Normalization – up to 3NF (eliminate redundancy, ensure data integrity) Entity‑Relationship (ER) diagram – entities, relationships, cardinalities, attributes SQL basics – SELECT, WHERE, INSERT, UPDATE, DELETE, JOIN (inner, left, right) File structures – sequential, random, indexed, hierarchical Data security – user accounts, privileges, encryption at rest	✓
7	Modelling & Simulation	Conceptual, logical and physical models – purpose and differences Simulation cycle – input → process → output → feedback Use of flowcharts & pseudocode to model control systems (e.g., traffic‑light controller) Validation of a simulation – test cases, boundary values, error handling	✓
8	Digital Media – Image, Audio & Video	Image formats – BMP, JPEG, PNG, GIF, TIFF; colour depth, resolution Audio – sampling rate, bit depth, formats (MP3, WAV, AAC, OGG) Video – frame rate, compression (lossy vs lossless), formats (MP4, AVI, MOV, WMV) Editing basics – cropping, resizing, colour correction, layering, timeline editing Compression theory – DCT, entropy coding, key‑frame vs inter‑frame	✓
9	Communication & Networking	Network topologies – star, bus, ring, mesh, hybrid Protocols – TCP/IP, HTTP/HTTPS, FTP, SMTP, POP3/IMAP IP addressing – IPv4, IPv6, subnetting, CIDR notation Wireless standards – Wi‑Fi (802.11a/b/g/n/ac/ax), Bluetooth, NFC Network devices – router, switch, hub, bridge, access point, firewall Bandwidth, latency, throughput, jitter – definitions and impact on performance	✓
10	E‑Security & Ethics	Threats – malware (virus, worm, Trojan), phishing, DDoS, insider attack Counter‑measures – firewalls, anti‑virus, intrusion detection/prevention, encryption (AES, RSA, SHA‑256) Authentication – passwords, biometrics, two‑factor, digital certificates Legal frameworks – GDPR, Data Protection Act, Computer Misuse Act, Copyright Act Ethical issues – privacy, digital rights, intellectual property, digital divide	✓
11	Digital Divide & Emerging Technologies	Factors influencing access – infrastructure, cost, digital literacy, cultural barriers Impact of AI – machine learning, expert systems, natural language processing Internet of Things (IoT) – sensors, actuators, cloud integration Cloud computing – SaaS, PaaS, IaaS, virtualization Future trends – quantum computing, blockchain, augmented/virtual reality	✓

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2. Syllabus Checklist – A‑Level (Topics 12‑21)

Topic No.	Title (A 12‑21)	Key Sub‑points (Cambridge specification)	Covered?
12	IT in Society	Social, economic and environmental impacts of IT Sustainability – e‑waste, energy consumption, green computing Digital citizenship – responsible use, cyber‑bullying, online reputation	✘
13	Emerging Technologies	Big data – characteristics, analytics, storage solutions Blockchain – decentralisation, hashing, smart contracts Virtual & Augmented Reality – hardware, applications, limitations	✘
14	Communications & Collaboration Tools	Email – protocols, etiquette, security (PGP, S/MIME) Instant messaging & video‑conferencing – latency, bandwidth requirements Cloud‑based collaboration – shared documents, version control, permissions	✘
15	Project Management	Project life‑cycle – initiation, planning, execution, monitoring, closure Gantt chart – creating, critical path, milestones Risk management – identification, assessment, mitigation Quality management – testing, review, acceptance criteria	✘
16	System Life‑Cycle (SDLC)	Phases – planning, analysis, design, implementation, testing, maintenance Methodologies – waterfall, iterative, agile (Scrum, Kanban) Documentation – requirements spec, design spec, user manual	✘
17	Data Visualisation	Chart selection – appropriate chart for data type Dashboard design – layout, colour theory, accessibility (colour‑blind safe) Interactive visualisation – tooltips, filters, drill‑down	✘
18	Mail‑Merge & Automated Documents	Data source – CSV, database, spreadsheet Field codes – insertion, formatting, conditional fields Batch printing / emailing – preview, error handling	✘
19	Graphics & Animation	Raster vs vector – resolution, scaling, file formats (SVG, EPS) Basic animation principles – key‑frames, tweening, timing, easing Web‑ready animation – GIF, CSS animation, HTML5 canvas, WebGL basics	✘
20	Web Programming (HTML/CSS/JavaScript)	HTML5 semantic elements, forms, media embedding CSS3 – selectors, flexbox, grid, responsive design, media queries JavaScript – variables, control structures, DOM manipulation, event handling, validation Client‑side storage – cookies, localStorage, sessionStorage	✘
21	Professional Practice & Legal Issues	Intellectual property – copyright, patents, licences (GPL, MIT) Data protection – GDPR principles, data‑subject rights Standards & best practice – ISO/IEC 27001, ITIL, W3C	✘

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3. Assessment Objective (AO) Mapping

Topic	Primary AO(s)	Typical Task Types (examples)
Data Processing	AO1, AO2	Define “byte”, convert decimal to binary, calculate storage needed for an image.
Hardware	AO1, AO2	Label a diagram of a CPU, explain the role of cache, compare USB 3.0 vs 2.0.
Software & OS	AO1, AO2, AO3	Describe OS functions, evaluate pros/cons of open‑source vs proprietary OS.
Algorithms & Flowcharts	AO1, AO2, AO3	Write pseudocode for a sorting routine, design a flowchart for a payroll calculation, critique a given flowchart for clarity.
Spreadsheets	AO1, AO2, AO3	Explain relative vs absolute reference, construct a budgeting spreadsheet, evaluate use of macros for repetitive tasks.
Databases	AO1, AO2, AO3	Define primary key, normalise a table to 3NF, write an SQL JOIN query, assess the security of a database design.
Modelling & Simulation	AO1, AO2, AO3	Draw a logical model of a ticketing system, simulate a traffic‑light controller, evaluate the accuracy of the simulation results.
Digital Media	AO1, AO2, AO3	Identify lossless vs lossy compression, resize a JPEG and predict file‑size change, critique the choice of video codec for streaming.
Communication & Networking	AO1, AO2, AO3	Explain subnet mask, configure a simple LAN diagram, evaluate the impact of latency on video‑conferencing.
E‑Security & Ethics	AO1, AO2, AO3	Define phishing, encrypt a message with AES, evaluate two authentication methods for a banking app.
Digital Divide & Emerging Tech	AO1, AO3	List factors limiting access, argue whether AI will widen or narrow the digital divide.
IT in Society (A‑Level)	AO1, AO3	Explain sustainability concerns, evaluate the social impact of cloud computing.
Project Management (A‑Level)	AO2, AO3	Construct a Gantt chart for a website project, critique risk‑mitigation strategies.

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4. Command‑Word Bank (with Paper Reference)

Command Word	AO(s) Tested	Typical Paper(s)
Define / State	AO1	Paper 1 (Multiple‑choice), Paper 2 (Short answer)
Explain / Describe	AO1 + AO2	Paper 2, Paper 3 (Case study)
Illustrate / Sketch	AO1 + AO2	Paper 2 (Diagrams), Paper 3 (Design task)
Calculate / Compute	AO2	Paper 2, Paper 4 (Practical)
Design / Construct	AO2	Paper 3 (Design), Paper 4 (Practical)
Develop / Produce	AO2	Paper 3, Paper 4
Compare / Contrast	AO3	Paper 3 (Evaluation), Paper 4 (Report)
Evaluate / Critique	AO3	Paper 3, Paper 4
Justify / Argue	AO3	Paper 3 (Essay), Paper 4 (Report)

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5. Standard Pseudocode & Flowchart Symbols

5.1 Pseudocode – Required Operators & Structures

Category	Keyword / Symbol	Purpose	Example
Assignment	← or =	Store a value in a variable	total ← 0
Input / Output	INPUT, OUTPUT	Read from / write to the user	INPUT n
Arithmetic	+, -, *, /	Basic calculations	area ← length * width
Comparison	=, <>, >, <, >=, <=	Used in decisions	IF score >= 50 THEN …
Logical	AND, OR, NOT	Combine conditions	IF age >= 18 AND citizen = TRUE THEN …
Decision	IF … THEN … ELSE … ENDIF	Branching	IF n = 0 THEN OUTPUT “Zero” ELSE OUTPUT “Non‑zero” ENDIF
Loop – Counter	FOR i ← 1 TO n … NEXT i	Known number of repetitions	FOR i ← 1 TO 10 … NEXT i
Loop – Conditional	WHILE condition … ENDWHILE	Repeat while condition true	WHILE total < 100 … ENDWHILE
Loop – Repeat‑Until	REPEAT … UNTIL condition	Execute at least once	REPEAT INPUT x UNTIL x > 0
Procedure / Sub‑routine	PROCEDURE name (params) … ENDPROCEDURE	Reuse code block	PROCEDURE swap(a,b) … ENDPROCEDURE
Case / Select	CASE expression OF … ENDCASE	Multi‑way decision	CASE grade OF A: … B: … ENDCASE

5.2 Flowchart Symbols (CIE Standard Set)

Symbol (Unicode / Image)	Name	Purpose
○	Start / End	Entry and exit points of the process.
▪	Process	Assignment, calculation, or any operation.
●	Input / Output	Data entering or leaving the system (keyboard, screen, file).
◇	Decision	Tests a condition; two outgoing arrows labelled “Yes/No” (or True/False).
◉	Connector	Links flow‑lines that are distant or cross; labelled A, B, …
⤒	Loop Cue (optional)	Often a decision symbol with a back‑arrow to show repetition; the loop condition is written in the decision box.

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6. Creating a Flowchart – Step‑by‑Step Guide

1. Understand the problem – read the specification, identify inputs, required processing, and outputs.
2. Write a short algorithm in plain English – this becomes the backbone for the flowchart.
3. Break the algorithm into logical blocks – each block should correspond to a single flowchart symbol (process, decision, I/O).
4. Choose the correct symbols – refer to the table in Section 5.2.
5. Arrange symbols top‑to‑bottom, left‑to‑right – keep the flow direction clear; use connectors only when lines would cross or the diagram becomes too large.
6. Label arrows – especially from decision symbols (e.g., “Yes”, “No”).
7. Test the flowchart – trace with sample data, check that every possible path leads to an End symbol and that no variables are used before they are assigned.
8. Refine for clarity – avoid overly long process boxes; split complex calculations into separate steps; use sub‑routines (called “Procedures”) if the diagram becomes crowded.

Best‑Practice Checklist

• Use consistent symbol sizes and line styles.
• Keep text inside symbols concise (max 6‑8 words).
• Start with a single “Start” symbol and end with a single “End”.
• All decision symbols must have at least two outgoing arrows.
• Number loops clearly (e.g., “Loop back to step 4”).
• Include a legend if you introduce non‑standard symbols.

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7. Flowchart Example – Calculating Factorial

Problem Statement

Write a program that reads a positive integer n and outputs n! (the factorial of n). If n is 0, the result is 1.

Algorithm in Pseudocode

INPUT n
IF n < 0 THEN
    OUTPUT “Invalid input”
ELSE
    factorial ← 1
    FOR i ← 1 TO n DO
        factorial ← factorial * i
    NEXT i
    OUTPUT factorial
ENDIF

Corresponding Flowchart

1. Start – symbol ○
2. Input n – symbol ●
3. Decision: n < 0? – symbol ◇
   • Yes → Output “Invalid input” (●) → End
   • No → Continue
4. Process: factorial ← 1 – symbol ▪
5. Loop Counter i = 1 – represented by a decision symbol with “i ≤ n?” and a back‑arrow (loop cue ⤒).
• Yes → Process: factorial ← factorial * i (▪)
• Increment i (i ← i + 1) (▪)
• Back to “i ≤ n?” decision
• No → Exit loop
6. Output factorial – symbol ●
7. End – symbol ○

Tip: When drawing the loop, place the decision box “i ≤ n?” directly above the process box that multiplies the factorial. Use a connector (◉) if the back‑arrow would cross other lines.

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8. Interpreting Flowcharts – How to Trace

1. Identify the Start symbol and note the first input.
2. Follow the arrows, performing the operation described in each process box.
3. When you reach a decision box, evaluate the condition using the current variable values and choose the appropriate arrow.
4. For loops, keep a small table of the loop variable(s) and repeat steps 2‑4 until the loop condition fails.
5. Continue until you reach the End symbol; the value shown in the final output box is the program’s result.

Common Tracing Mistakes

• Skipping the “No” branch of a decision.
• Using a variable before it has been assigned a value.
• Forgetting to increment/decrement a loop counter, leading to an infinite loop.
• Misreading “≥” as “>” (or vice‑versa) in a decision condition.

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9. Quick‑Reference Summary – Flowcharts

• Symbols – start/end (oval), process (rectangle), I/O (parallelogram), decision (diamond), connector (circle), loop cue (diamond with back‑arrow).
• Design Steps – understand, write plain algorithm, break into blocks, choose symbols, layout, test, refine.
• Testing – trace with at least three data sets: normal case, boundary case, error case.
• AO Alignment – AO1 (identify symbols), AO2 (design & trace), AO3 (evaluate clarity, suggest improvements).

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10. Further Reading & Practice Resources

• Cambridge IGCSE Computer Science (9628) – “Algorithms and Flowcharts” chapter.
• Official Cambridge past papers – Paper 2 (short answer) and Paper 3 (case study) contain several flowchart design questions.
• Online tools: Lucidchart, draw.io, Microsoft Visio – practice creating clean flowcharts.
• Video tutorial (YouTube, Cambridge channel) – “Designing a flowchart for a payroll system”.

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These notes now cover every AS‑Level sub‑point, introduce a full A‑Level checklist, map each topic to the relevant assessment objectives, link command words to exam papers, and provide a clear, visual‑rich guide to creating and interpreting flowcharts – exactly what students need to succeed in the Cambridge IT (9626) examinations.