Cambridge IGCSE ICT 0417 – The Systems Life Cycle & Data Structures
7. The Systems Life Cycle
The systems life cycle (SLC) provides a structured approach to developing, implementing and maintaining information systems. It ensures that each stage is completed before moving to the next, reducing risk and improving quality.
Stages of the Systems Life Cycle
Planning – Identify the problem or opportunity and define the scope.
Analysis – Gather detailed requirements from users and document them.
Design – Create logical and physical designs for data, processes and user interfaces.
Development – Build or configure the system according to the design specifications.
Implementation – Install, test and roll‑out the system to users.
Maintenance – Provide ongoing support, updates and improvements.
Suggested diagram: A circular flowchart showing the six stages of the systems life cycle.
Objective: File/Data Structures
A file or database is organised into records, each consisting of fields. Understanding the components of a field is essential for designing efficient data storage.
Key Components of a Field
Field Name – A descriptive identifier (e.g., FirstName).
Field Length – The maximum number of characters or bytes the field can hold.
Data Type – The kind of data stored (e.g., Text, Integer, Decimal, Date, Boolean).
Coding of Data – A method of representing values with a single character or code (e.g., M for Male, F for Female).
Example: Student Record Structure
Field Name
Field Length
Data Type
Coding / Example \cdot alue
StudentID
8
Alphanumeric
20230001
FirstName
20
Text
Emily
LastName
25
Text
Brown
Gender
1
Character
M / F
DateOfBirth
10
Date (DD/MM/YYYY)
15/04/2005
EnrolYear
4
Integer
2023
IsFullTime
1
Boolean
Y / N
Calculating Record Size
To estimate the storage required for a single record, sum the field lengths (in bytes). For character data, 1 character = 1 byte (assuming ASCII). For Unicode, use 2 bytes per character.