Introduction
Every piece of software — from a small mobile app to a national banking system — is built by following a series of organized stages. The Software Development Life Cycle (SDLC) is the structured process (a framework) that describes those stages: from the first idea, through analysis, design, coding, testing, deployment, and finally maintenance. An SDLC model is a particular arrangement of these stages — a strategy that decides the order, overlap, and repetition of the phases.
For BCS, Bank IT, and IT-officer examinations, SDLC models are among the most frequently asked topics in Software Engineering. Examiners love this area because it produces clean, factual MCQs: "Which model is also called the linear-sequential model?", "Who proposed the Spiral model?", "In which model is a prototype built first?". If you master the phases, the model characteristics, and the comparison points, you can answer almost any question in this area with confidence.
Learning objectives
- Define SDLC and explain why a structured process is needed.
- List and explain the standard phases of the SDLC in correct order.
- Describe the major SDLC models: Waterfall, V-Model, Incremental, Iterative, Prototype, Spiral, RAD, Big Bang, and Agile.
- State the advantages, disadvantages, and best-use situations of each model.
- Compare the models across key dimensions (risk handling, cost of change, flexibility, customer involvement).
- Correctly answer exam MCQs, including "who proposed", "also known as", and "which model suits scenario X".