Topic 1
2.1 System life cycle
2.1 System life cycle learning objectives and workbook content.
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11.2.1.1
Paper 2
explain the life cycle stages used in the solving of problems
Theory
Overview
What is the System Life Cycle?
The system life cycle is a structured process used to analyse, design, develop, test, implement, evaluate, and maintain a system.
It helps developers solve problems step by step instead of building a system without a clear plan.
Mini-example: a school wants a Library Management System. Developers first collect information about student and librarian needs, then plan the system, build it, test it, install it, and improve it over time.
Common mistake: students often confuse analysis with design. Analysis is about finding out what is needed. Design is about planning how it will work.
It helps developers solve problems step by step instead of building a system without a clear plan.
Mini-example: a school wants a Library Management System. Developers first collect information about student and librarian needs, then plan the system, build it, test it, install it, and improve it over time.
Common mistake: students often confuse analysis with design. Analysis is about finding out what is needed. Design is about planning how it will work.
Text
Main Stages of the System Life Cycle
Main stages:
1. Analysis – collect information and identify the problem.
2. Design – plan inputs, outputs, storage, interface, and algorithms.
3. Development – create the program or system.
4. Testing – find and fix errors.
5. Implementation – install and use the system.
6. Documentation – prepare user guides and technical notes.
7. Evaluation – review whether the system solved the original problem.
8. Maintenance – update, improve, and repair the system over time.
Quick clue guide:
collect user needs → analysis
plan screens / algorithms / data storage → design
write code → development
find bugs → testing
install system → implementation
write manuals → documentation
review success → evaluation
fix after release → maintenance
1. Analysis – collect information and identify the problem.
2. Design – plan inputs, outputs, storage, interface, and algorithms.
3. Development – create the program or system.
4. Testing – find and fix errors.
5. Implementation – install and use the system.
6. Documentation – prepare user guides and technical notes.
7. Evaluation – review whether the system solved the original problem.
8. Maintenance – update, improve, and repair the system over time.
Quick clue guide:
collect user needs → analysis
plan screens / algorithms / data storage → design
write code → development
find bugs → testing
install system → implementation
write manuals → documentation
review success → evaluation
fix after release → maintenance
Workbook
Matching
Match each stage to its description
Linked LO: 11.2.1.1
Match each stage of the system life cycle with the correct description.
Matching
Match each stage to its description
Linked LO: 11.2.1.1
Match each stage of the system life cycle with the correct description.
Part A
Connect each stage with the correct description.
Click one item in Column A, then one item in Column B to create a pair.
Column A
Column B
11.2.1.2
Paper 2
analyse the advantages and disadvantages of agile, waterfall and spiral models
Theory
Worked example
Waterfall, Agile and Spiral Models
Waterfall: a linear model where each stage is completed before the next begins.
Advantages: clear structure, easy to understand, suitable when requirements are fixed.
Disadvantages: difficult to make changes later, less flexible.
Agile: a flexible model based on short repeated cycles and regular feedback.
Advantages: handles changing requirements well, encourages feedback, finds problems earlier.
Disadvantages: harder to plan everything at the start, depends on strong communication.
Spiral: a model that repeats stages in cycles and focuses strongly on risk analysis.
Advantages: useful for complex or risky projects, risk is considered carefully.
Disadvantages: more expensive, more complex to manage.
How to choose in tasks:
clear and stable requirements → Waterfall
changing requirements and frequent feedback → Agile
large, risky, complex project → Spiral
Advantages: clear structure, easy to understand, suitable when requirements are fixed.
Disadvantages: difficult to make changes later, less flexible.
Agile: a flexible model based on short repeated cycles and regular feedback.
Advantages: handles changing requirements well, encourages feedback, finds problems earlier.
Disadvantages: harder to plan everything at the start, depends on strong communication.
Spiral: a model that repeats stages in cycles and focuses strongly on risk analysis.
Advantages: useful for complex or risky projects, risk is considered carefully.
Disadvantages: more expensive, more complex to manage.
How to choose in tasks:
clear and stable requirements → Waterfall
changing requirements and frequent feedback → Agile
large, risky, complex project → Spiral
Workbook
Multiple Choice
Choose the best development model
Linked LO: 11.2.1.2
A school is developing a library system. The librarian wants to test parts of the system early and expects some requirements to change after trying the first version.
Multiple Choice
Choose the best development model
Linked LO: 11.2.1.2
A school is developing a library system. The librarian wants to test parts of the system early and expects some requirements to change after trying the first version.
Part A
Which development model is the most suitable?
Part B
Explain your choice in one or two sentences.
11.2.1.3
Paper 2
describe data collection methods
Theory
Text
Data Collection and Data Analysis
Data collection methods:
Interview – good for detailed answers and follow-up questions.
Questionnaire – good for collecting responses from many users quickly.
Observation – useful when seeing how the current system works is important.
Existing documents – useful for studying forms, reports, and records from the current system.
Data analysis techniques:
counting responses, comparing answers, identifying repeated needs, and summarising results using tables or charts.
How to choose the method:
many students → questionnaire
one expert user → interview
understand current process → observation
study current records → existing documents
Interview – good for detailed answers and follow-up questions.
Questionnaire – good for collecting responses from many users quickly.
Observation – useful when seeing how the current system works is important.
Existing documents – useful for studying forms, reports, and records from the current system.
Data analysis techniques:
counting responses, comparing answers, identifying repeated needs, and summarising results using tables or charts.
How to choose the method:
many students → questionnaire
one expert user → interview
understand current process → observation
study current records → existing documents
Workbook
Short Answer
Choose the best data collection method
Linked LO: 11.2.1.3
The school wants to collect opinions from 400 students about which search features should be included in the new library system.
Short Answer
Choose the best data collection method
Linked LO: 11.2.1.3
The school wants to collect opinions from 400 students about which search features should be included in the new library system.
Part A
Which data collection method is the most suitable? Explain why it is better than an interview.
11.2.1.4
Paper 2
compare different data analysis techniques
Theory
No theory linked to this LO yet.
Workbook
Short Answer
Analyse collected data
Linked LO: 11.2.1.4
A questionnaire produced these results: 82% want search by title, 76% want search by author, 21% want dark mode, and 88% want a clear borrowed-books section.
Short Answer
Analyse collected data
Linked LO: 11.2.1.4
A questionnaire produced these results: 82% want search by title, 76% want search by author, 21% want dark mode, and 88% want a clear borrowed-books section.
Part A
Identify two important features that should be included first and explain why.
11.2.1.5
Paper 2
compare alternative solutions to a problem in order to choose the most effective algorithm
Theory
Exam tip
Choosing Solutions and Writing Requirements
To choose the most effective solution, compare speed, simplicity, storage needed, accuracy, ease of use, and cost.
Functional requirements describe what the system must do.
Examples: The system must allow students to search by title. The system must record borrowed books.
Non-functional requirements describe qualities the system should have.
Examples: The system should be easy to use. The system should keep user data secure. The system should respond quickly.
Good requirements should be clear, specific, and based on collected information.
Functional requirements describe what the system must do.
Examples: The system must allow students to search by title. The system must record borrowed books.
Non-functional requirements describe qualities the system should have.
Examples: The system should be easy to use. The system should keep user data secure. The system should respond quickly.
Good requirements should be clear, specific, and based on collected information.
Workbook
Long Answer
Write system requirements
Linked LO: 11.2.1.5
Collected information shows that students want to search for books by title and author, librarians want to add and remove book records, the school wants the system to be easy to use, and the school wants user data to be secure.
Long Answer
Write system requirements
Linked LO: 11.2.1.5
Collected information shows that students want to search for books by title and author, librarians want to add and remove book records, the school wants the system to be easy to use, and the school wants user data to be secure.
Part A
Write two functional requirements and two non-functional requirements.
11.2.1.6
Paper 2
use data flow diagrams (DFD) to input, process, store and output data in computing systems
Theory
Key terms
DFDs and Flowcharts
A Data Flow Diagram (DFD) shows how data moves through a system.
It focuses on input, process, storage, and output.
DFD elements:
External entity – a person or system outside the process
Process – transforms or handles data
Data store – holds data
Data flow – arrow showing movement of data
DFD rules:
Data should move through arrows.
Processes must transform data.
Data should not move directly from entity to entity without a process.
Data should not move directly from store to store without a process.
DFD types:
Context diagram / Level 0 – whole system as one process.
Level 1 DFD – breaks the system into smaller processes.
A flowchart shows the sequence of actions or decisions in a process.
Main symbols: oval = start/end, parallelogram = input/output, rectangle = process, diamond = decision.
Difference:
DFD shows how data moves.
Flowchart shows the order of steps.
It focuses on input, process, storage, and output.
DFD elements:
External entity – a person or system outside the process
Process – transforms or handles data
Data store – holds data
Data flow – arrow showing movement of data
DFD rules:
Data should move through arrows.
Processes must transform data.
Data should not move directly from entity to entity without a process.
Data should not move directly from store to store without a process.
DFD types:
Context diagram / Level 0 – whole system as one process.
Level 1 DFD – breaks the system into smaller processes.
A flowchart shows the sequence of actions or decisions in a process.
Main symbols: oval = start/end, parallelogram = input/output, rectangle = process, diamond = decision.
Difference:
DFD shows how data moves.
Flowchart shows the order of steps.
Workbook
Matching
DFD or Flowchart?
Linked LO: 11.2.1.6
Decide whether each statement describes a DFD or a Flowchart.
Matching
DFD or Flowchart?
Linked LO: 11.2.1.6
Decide whether each statement describes a DFD or a Flowchart.
Part A
Connect each statement with the correct diagram type.
Click one item in Column A, then one item in Column B to create a pair.
Column A
Column B
11.2.1.7
Paper 2
use flow charts to input, process, store and output data in computing systems
Theory
No theory linked to this LO yet.
Workbook
No workbook tasks linked to this LO yet.
11.2.1.8
Paper 2
develop a system requirement based on collected information
Theory
No theory linked to this LO yet.
Workbook
No workbook tasks linked to this LO yet.
Glossary
System life cycle
A structured process used to develop a system in stages.
Analysis
The stage where user needs and the current problem are identified.
Design
The stage where the structure of the new system is planned.
Agile
A flexible development model based on short repeated cycles and feedback.
Waterfall
A linear development model where each stage is completed before the next.
Spiral
A development model that focuses on repeated cycles and risk analysis.
Questionnaire
A written set of questions used to collect information from many users.
Data Flow Diagram (DFD)
A diagram showing how data moves through a system.
Flowchart
A diagram showing the sequence of steps in a process or algorithm.
Functional requirement
A statement describing what the system must do.