7 The Systems Life Cycle (SLC)
The SLC gives a systematic, step‑by‑step framework for creating, installing, evaluating and maintaining an information system. At each stage decisions are recorded, reviewed and, where necessary, revised before moving on.
Key Stages
- Planning & Feasibility
- Define the problem, set clear objectives and scope.
- Analyse costs, benefits, risks and resource requirements.
- Produce a feasibility report and obtain stakeholder approval.
- Analysis
- Gather detailed user requirements (functional & non‑functional).
- Create use‑case diagrams, data‑flow diagrams and a requirements specification.
- Design
- Develop logical designs (data models, algorithms) and physical designs (hardware, network, UI mock‑ups).
- Produce a technical design document that will guide development.
- Development
- Write code, configure hardware, set up databases and integrate components.
- Document source‑code comments, build scripts and configuration settings.
- Testing
- Unit, integration, system and acceptance testing against the specifications.
- Record defects, retest after fixes and produce a test‑summary report.
- Implementation
- Install the system, migrate data, train users and provide support material.
- Choose an implementation method (see table below).
- Evaluation
- Compare the delivered system with the original brief.
- Assess efficiency, usability, reliability and security.
- Identify limitations and suggest improvements.
- Maintenance (ongoing)
- Provide user support, apply updates/patches and implement enhancements.
- Maintain change logs and version‑controlled documentation.
Implementation Methods (Syllabus 7.5)
| Method |
How it works |
Advantages |
Disadvantages |
| Direct change‑over |
Old system is switched off and the new system goes live at once. |
Fast; no need to run two systems. |
High risk – any failure stops the service. |
| Parallel |
Both old and new systems run together for a set period. |
Safe fallback; allows performance comparison. |
More costly; duplicate work. |
| Pilot |
New system is introduced to a limited user group first. |
Problems identified early; limited impact of failures. |
May not represent whole‑organisation use. |
| Phased |
System is rolled out in stages (e.g., module‑by‑module). |
Reduces risk; users adapt gradually. |
Longer overall rollout time. |
Evaluation of a Solution (AO3)
- Check every functional and non‑functional requirement has been met.
- Measure efficiency (speed, resource use) and usability (ease of learning, satisfaction).
- Identify any limitations – missing features, performance bottlenecks, security gaps.
- Suggest realistic improvements – upgrades, additional training, process changes.
Example: A school‑management database is evaluated by confirming it records attendance, grades and timetables (requirements), returns results in ≤ 2 seconds per query (efficiency), can be used by teachers after a 30‑minute induction (usability), and noting the lack of a mobile app (limitation). An improvement could be to develop a simple mobile interface.
Technical and User Documentation (Syllabus 7.5)
Technical Documentation
- Characteristics
- Highly detailed and precise.
- Uses technical terminology, standards and conventions.
- Contains diagrams, code listings, API specifications, configuration settings.
- Structured for quick reference (indexed, searchable, version‑controlled).
- Uses
- Guide coding, integration and system configuration.
- Support installation, deployment and migration.
- Provide a basis for test‑case design.
- Aid troubleshooting, upgrades and future development.
- Purpose
- Ensure consistency and quality in system creation.
- Facilitate knowledge transfer within the technical team.
- Reduce errors, re‑work and downtime.
- Supply legal/compliance evidence (e.g., data‑handling procedures).
User Documentation
- Characteristics
- Clear, concise and written in plain language.
- Task‑focused – “how to” perform a specific activity.
- Includes step‑by‑step instructions, screenshots, mock‑ups or short videos.
- Organised by user role, workflow or feature set.
- Uses
- Training new staff.
- Reference for routine operations.
- Self‑service support and help‑desk assistance.
- Ensuring compliance with operational procedures.
- Purpose
- Enable users to operate the system efficiently and safely.
- Minimise user errors and support calls.
- Promote consistent use of system features.
- Provide legal or safety instructions where required.
Documentation Checklist – Required Components (Syllabus 7.5)
| Component |
Technical Documentation |
User Documentation |
| Purpose of the system |
Technical overview, design goals, architecture description |
Plain‑language description of what the system does and who benefits |
| Limitations / known issues |
Performance limits, compatibility notes, hardware constraints |
Restrictions users must be aware of (e.g., file‑size limits, supported browsers) |
| Hardware & software requirements |
Server specifications, OS, middleware, libraries, network topology |
Minimum PC specs, required operating system, browsers, peripherals |
| Installation / setup instructions |
Server installation, network configuration, database creation, security settings |
Step‑by‑step install‑wizard guide, first‑run configuration, licensing |
| Running the system (start, log in, shut down) |
Service start‑up scripts, command‑line options, environment variables |
Login procedure, navigation basics, logout and shutdown steps |
| Saving, printing, editing files |
File‑system paths, backup scripts, version‑control commands |
How to save a document, print a report, edit a record, export data |
| Error handling & troubleshooting |
Error codes, log‑file locations, corrective actions, rollback procedures |
Common error messages, FAQ‑style fixes, contact details for support |
| FAQs / Glossary |
Technical term definitions, acronyms, protocol specifications |
Plain‑language glossary of key terms used in the user guide |
Version Control & Document Indexing
- Adopt a consistent naming convention, e.g.
DocName_v1.0_2025‑12‑01.pdf.
- Include a revision‑history table at the start of each document (date, author, changes).
- Store documents in a controlled folder structure or a wiki with appropriate access rights.
- Number sections, provide a table of contents and use cross‑references for easy navigation.
Comparison of Technical and User Documentation
| Aspect |
Technical Documentation |
User Documentation |
| Audience |
Developers, engineers, testers, maintainers |
End‑users, managers, support staff |
| Language |
Technical, formal, uses standards |
Plain, conversational, task‑focused |
| Content Types |
Design specs, code comments, architecture diagrams, configuration files |
User manuals, quick‑start guides, FAQs, tutorial videos |
| Level of Detail |
High – algorithms, data structures, interfaces |
Moderate – “how‑to” steps with screenshots |
| Update Frequency |
Often updated with each code change or patch |
Updated when UI or procedures change |
Creating Effective Documentation
- Identify the target audience and their specific information needs.
- Choose an appropriate format (printed manual, online help, wiki, video tutorial).
- Use consistent headings, numbering, terminology and style.
- Include examples, screenshots, diagrams or short videos where they aid understanding.
- Test the documentation with a sample of the intended users and revise accordingly.
- Maintain version control, record revisions and keep an index or table of contents.
Documentation Checklist for Each SLC Stage
- Planning – Project charter, feasibility report, stakeholder analysis.
- Analysis – Requirements specification, use‑case diagrams, data‑flow diagrams.
- Design – System architecture, database schema, interface mock‑ups, technical design document.
- Development – Source‑code comments, build scripts, configuration guides.
- Testing – Test plans, test cases, defect logs, test‑summary report.
- Implementation – Installation guide, migration plan, training materials, user manual.
- Evaluation – Evaluation report (requirements match, efficiency, user feedback, improvement suggestions).
- Maintenance – Change log, support procedures, backup & recovery documentation.
8 Safety and Security
Physical Safety
- Keep cables tidy and away from walkways.
- Use proper lifting techniques for heavy hardware.
- Ensure adequate ventilation for servers and avoid overheating.
- Follow electrical safety rules – do not plug/unplug equipment while powered.
e‑Safety (Health & Well‑being)
- Maintain correct posture; keep monitor at eye level.
- Take regular breaks (e.g., 5 minutes every hour) to reduce eye strain and repetitive‑strain injury.
- Adjust screen brightness and use anti‑glare filters.
- Use headphones at a safe volume and keep the workstation ergonomically sound.
Data Protection & Legal Requirements
- Store personal data securely – use strong passwords, encryption and access controls.
- Comply with data‑protection legislation (e.g., GDPR): obtain consent, keep data only as long as needed, provide a right to access and delete.
- Maintain a data‑retention schedule and regular backups.
- Document any data‑handling procedures for audit purposes.
Threats to ICT Systems
- Malware (viruses, ransomware, spyware).
- Phishing and social engineering attacks.
- Unauthorised access (hacking, insider threats).
- Denial‑of‑service (DoS) attacks.
- Physical theft or loss of devices.
Protection Measures
- Install and regularly update firewalls and anti‑virus software.
- Apply operating‑system and application patches promptly.
- Use strong, unique passwords and enable two‑factor authentication.
- Implement role‑based access control and least‑privilege principles.
- Encrypt sensitive files and communications (e.g., TLS/SSL for web traffic).
- Maintain regular backups and test restoration procedures.
9 Understanding the Audience
- Analyse who will read the document (technical staff, end‑users, managers) and what they already know.
- Adapt language, tone and level of detail accordingly – avoid jargon for non‑technical users.
- Consider accessibility (large fonts, clear contrast) for users with disabilities.
- Respect copyright: obtain permission for third‑party images, code snippets or diagrams, or use openly licensed resources and provide proper attribution.
10 Communication (Email, Internet & Evaluating Information)
Email Etiquette
- Use a clear subject line and professional greeting.
- Keep the message concise; use bullet points for readability.
- Check spelling and tone before sending.
- Attach files using appropriate formats and mention them in the body.
- Use “Reply‑All” only when necessary.
Internet Use & Netiquette
- Distinguish between intranet (internal), extranet (partner) and the World Wide Web.
- Observe organisational policies on acceptable use, bandwidth and content.
- Protect personal information; avoid sharing passwords or confidential data.
- Use secure connections (HTTPS) for sensitive transactions.
Evaluating Information Sources
- Check the author’s credentials and the site’s domain (.gov, .edu, .org are usually reliable).
- Assess the purpose – is it to inform, persuade, sell, or entertain?
- Look for citations, dates and evidence of peer review.
- Cross‑reference with at least two other reputable sources.
- Beware of bias, outdated data and sensational headlines.
11 File Management
- File Types – .doc/.docx (documents), .pdf (portable), .xls/.xlsx (spreadsheets), .ppt/.pptx (presentations), .jpg/.png/.gif (images), .html/.css/.js (web files).
- Naming Conventions – use meaningful, consistent names (e.g.,
Report_2025_Q1_v2.docx) and avoid spaces/special characters.
- Compression – zip files to reduce size for transfer; remember to label compressed archives.
- Backup – regular automated backups to external drives or cloud storage; verify restore capability.
12 Images
- Common formats: JPEG (photographs, lossy), PNG (transparent backgrounds, lossless), GIF (simple animations).
- Resolution: 72 dpi for web, 300 dpi for print.
- Basic editing – cropping, resizing, adjusting brightness/contrast – can be done with built‑in tools or free software (e.g., GIMP, Paint.NET).
- Use alt‑text for accessibility and SEO.
13 Layout, Styles & Proofreading
Layout & Styles
- Apply consistent paragraph styles (Heading 1, Heading 2, Normal) to enable automatic tables of contents.
- Use page margins, headers/footers and page numbers for professional appearance.
- Employ templates or master pages for repeated design elements.
Proofreading Tools
- Spell‑check and grammar check (built‑in or add‑ins).
- Readability statistics (Flesch‑Kincaid) to gauge audience suitability.
- Peer‑review – ask a colleague to read the document for clarity and errors.
14 Graphs & Charts
- Choose the right type: bar charts for comparisons, line graphs for trends, pie charts for parts‑of‑a‑whole, scatter plots for relationships.
- Label axes, include units, and provide a clear title.
- Use colour or shading consistently; avoid 3‑D effects that distort data.
- Provide a data source note underneath the chart.
15 Document Production (Word Processing)
- Create, edit and format text documents; insert tables, images, hyperlinks and footnotes.
- Use mail‑merge for bulk letters or labels.
- Apply automatic spelling/grammar checks and track changes for collaborative editing.
- Export to PDF for secure distribution.
16 Databases
- Key Concepts – tables, fields (columns), records (rows), primary key, foreign key, relationships.
- Design a logical data model (entity‑relationship diagram) before creating tables.
- Use queries (SELECT, WHERE, JOIN) to retrieve and manipulate data.
- Create forms for data entry and reports for presenting results.
- Maintain data integrity with validation rules and referential integrity constraints.
17 Presentations
- Structure: title slide, agenda, main content slides, conclusion, references.
- Design principles – keep slides uncluttered, use high‑contrast text/background, limit to 6‑bullet points per slide.
- Incorporate multimedia (images, video, audio) where it adds value.
- Practice delivery: speak clearly, maintain eye contact, use a remote clicker.
18 Spreadsheets
- Cells, rows, columns, worksheets – basic navigation.
- Formulas (e.g.,
=A1+B1) and functions (SUM, AVERAGE, VLOOKUP, IF).
- Use absolute vs. relative cell references.
- Data analysis tools – sorting, filtering, pivot tables, conditional formatting.
- Create charts directly from data ranges.
19 Website Authoring
- HTML basics – tags for headings (
<h1>–<h6>), paragraphs (<p>), links (<a href="...">), images (<img src="..." alt="...">).
- CSS for styling – selectors, properties (colour, margin, font), external style sheets.
- Linking pages together (internal navigation) and to external resources.
- Test in multiple browsers and ensure responsive design for different devices.
- Publish using a web host or a school intranet server; maintain a change log.
Key Take‑aways
- The Systems Life Cycle guides a project from idea to ongoing support, with clear documentation at each stage.
- Technical documentation underpins development and maintenance; user documentation empowers safe, efficient operation.
- Accurate, version‑controlled documentation reduces errors, saves time and provides legal/compliance evidence.
- Safety, security, audience awareness and effective communication are integral to responsible ICT practice.
- Mastery of file management, image handling, layout, proofreading, graphs, and the core ICT applications (word processing, databases, presentations, spreadsheets, web authoring) completes the IGCSE 0417 syllabus.