Software development life cycle (SDLC) models are frameworks that define the processes and stages involved in the development, deployment, and maintenance of software systems. Different SDLC models offer various approaches to organizing and executing these processes.

Waterfall Model

The waterfall model follows a linear and sequential approach to software development, where each phase must be completed before moving on to the next. The phases typically include requirements gathering, design, implementation, testing, deployment, and maintenance.

Advantages:

a. Clear and well-structured process.

b. Easy to understand and manage.

c. Each phase has specific deliverables and milestones.

d. Suitable for projects with stable and well-defined requirements.

Disadvantages:

a. Limited flexibility to accommodate changes once a phase is completed.

b. No working software is produced until late in the life cycle.

c. Customer feedback is not incorporated until the end, which may lead to dissatisfaction.

d. High risk of project failure if requirements are not accurately defined upfront.

Agile Model

Agile is an iterative and incremental approach to software development, emphasizing flexibility, customer collaboration, and rapid delivery of working software. Agile methods, such as Scrum and Kanban, involve breaking the project into small, manageable increments called sprints or iterations.

Advantages:

a. Flexibility to adapt to changing requirements and priorities.

b. Continuous involvement of stakeholders ensures that the final product meets their needs.

c. Early and frequent delivery of working software increments.

d. Emphasis on collaboration and communication within cross-functional teams.

Disadvantages:

a. Requires active involvement and commitment from all stakeholders.

b. Emphasis on working software over comprehensive documentation may lead to documentation gaps.

c. May not be suitable for projects with fixed requirements and tight deadlines.

d. Dependency on customer feedback can sometimes lead to scope creep and project delays.

Spiral Model

The spiral model combines elements of both waterfall and iterative development models, emphasizing risk analysis and mitigation throughout the life cycle. The model consists of multiple cycles, each involving risk identification, planning, implementation, and evaluation.

Advantages:

a. Early identification and mitigation of risks.

b. Allows for incremental development and refinement of software features.

c. Suitable for large and complex projects with evolving requirements.

d. Provides flexibility to accommodate changes at any stage of the development process.

Disadvantages:

a. Can be time-consuming and costly due to multiple iterations.

b. Requires experienced and skilled personnel to effectively manage risks.

c. Documentation and formal reviews may become cumbersome.

d. May not be suitable for small or straightforward projects.

V-Model

The V-Model is an extension of the waterfall model where testing activities are integrated into each phase of the development life cycle. It emphasizes the verification and validation of deliverables at each stage, ensuring that software meets quality standards.

Advantages:

a. Ensures early detection and correction of defects through parallel testing activities.

b. Improves overall quality by focusing on verification and validation.

c. Provides a systematic approach to software testing.

d. Well-suited for projects with strict quality and compliance requirements.

Disadvantages:

a. Rigidity in accommodating changes once development has started.

b. Requires significant upfront planning and documentation.

c. Testing activities may become bottlenecked if not properly managed.

d. Limited flexibility compared to iterative or agile models.

Iterative Model

The iterative model involves repeating cycles of development, where software is developed, tested, and refined in successive iterations. Each iteration adds new features or enhancements based on feedback from stakeholders.

Advantages:

a. Allows for incremental development and frequent releases.

b. Enables early validation of key features and functionalities.

c. Flexibility to incorporate changes at any stage of the development process.

d. Suitable for projects with evolving requirements and priorities.

Disadvantages:

a. Requires careful management of scope and requirements to prevent scope creep.

b. May lead to increased complexity if iterations are not well-planned.

c. Dependency on customer feedback and involvement can be challenging to manage.

d. Iterations may require additional time and resources compared to other models.

Tribhuwan University

Institute of Science and Technology

Model

Section A

Attempt any TWO questions

Section B

Attempt any EIGHT questions