JNTU MCA 2020 SOFTWARE ENGINEERING Previous Question Paper (October/ November - 2020 - R15)

The Waterfall model is a linear-sequential software development life cycle (SDLC) approach where progress flows steadily downwards through distinct phases. Each phase must be completed before the next begins, and there is typically no overlapping.

The phases are:

• Requirement Analysis: All possible requirements of the system to be developed are captured in a requirement specification document.
• System Design: The requirements are studied and the system architecture is designed.
• Implementation: The system is developed in small units which are integrated in the next phase.
• Integration and Testing: All units are integrated and tested for faults and failures.
• Deployment and Maintenance: The product is deployed in the customer environment and maintained to address issues or enhancements.

Diagram representation: Requirements → System Design → Implementation → Integration & Testing → Deployment → Maintenance. This model is best suited for projects with well-defined, stable requirements.

The Spiral Model is a risk-driven process model that combines the iterative nature of prototyping with the controlled and systematic aspects of the waterfall model. It is particularly useful for large, expensive, and complicated projects.

The model is divided into four quadrants:

• Objective Setting: Identifying objectives for that phase and alternative solutions.
• Risk Assessment and Reduction: Identifying potential risks and developing strategies to resolve them, often through prototyping.
• Development and Validation: Developing the software and verifying it through testing.
• Review and Planning: Evaluating the results with the customer and planning the next iteration.

The project passes through these phases repeatedly in a spiral fashion, where each loop represents a phase of the software process. As the spiral progresses, the software grows in complexity and maturity, with each iteration reducing project risk.