Understand software development methods (agile, waterfall, RAD)

Resources | Subject Notes | Information Technology IT | Lesson Plan

System Life Cycle

The system life cycle (SLC) describes the stages a software system goes through from its initial conception to its eventual retirement. Understanding different software development methods is crucial for effectively managing this lifecycle.

Software Development Methods

Several methodologies exist for developing software. This section will explore three prominent methods: Waterfall, Agile, and Rapid Application Development (RAD).

Waterfall Model

The Waterfall model is a traditional, linear sequential approach. Progress flows steadily downwards through the following phases:

  • Requirements: Gathering and documenting all system requirements.
  • Design: Creating the system architecture and detailed design specifications.
  • Implementation: Coding the software based on the design.
  • Testing: Verifying that the software meets the requirements.
  • Deployment: Releasing the software to the users.
  • Maintenance: Addressing bugs and making enhancements.
Phase Description Key Deliverables
Requirements Gathering and documenting all system requirements. Requirements Specification Document
Design Creating the system architecture and detailed design specifications. Design Document
Implementation Coding the software based on the design. Source Code
Testing Verifying that the software meets the requirements. Test Reports, Bug Fixes
Deployment Releasing the software to the users. Deployed Software
Maintenance Addressing bugs and making enhancements. Updated Software, Bug Fixes

Advantages: Simple to understand and manage, well-suited for projects with clear and stable requirements.

Disadvantages: Inflexible, difficult to accommodate changes in requirements, high risk if requirements are not fully understood at the outset.

Agile Methodology

Agile is an iterative and incremental approach that emphasizes flexibility and customer collaboration. It breaks down the project into small, manageable iterations (sprints). Key principles include:

  • Customer collaboration
  • Responding to change over following a plan
  • Working software over comprehensive documentation
  • Individuals and interactions over processes and tools

Common Agile frameworks include Scrum and Kanban.

Advantages: Highly adaptable to changing requirements, faster time to market, improved customer satisfaction.

Disadvantages: Requires strong customer involvement, can be challenging to manage large projects, may lead to scope creep if not carefully managed.

Rapid Application Development (RAD)

RAD focuses on rapid prototyping and iterative development. It involves:

  • Identifying key requirements.
  • Creating a prototype of the system.
  • Iteratively refining the prototype based on user feedback.
  • Developing the final system from the refined prototype.

RAD often utilizes reusable components and tools to accelerate development.

Advantages: Fast development cycles, high user involvement, reduced risk of building the wrong product.

Disadvantages: Requires skilled developers and users, may not be suitable for complex projects with unclear requirements, can lead to a less polished final product if prototyping is not well-managed.

Comparison of Software Development Methods

Feature Waterfall Agile RAD
Approach Linear, sequential Iterative, incremental Rapid prototyping
Requirements Fixed at the beginning Evolving throughout the project Identified early, refined iteratively
Customer Involvement Limited High High
Flexibility Low High Medium
Risk Management High risk if requirements are unclear Lower risk due to iterative development Lower risk due to prototyping

The choice of software development method depends on the specific project requirements, the level of uncertainty, and the available resources.