Testing_105 : SDLC Models : Waterfall Model

A software development life cycle (SDLC) model is a conceptual framework describing all activities in a software development project from planning to maintenance. This process is associated with several models, each including a variety of tasks and activities.

Types of SDLC Models :

1. Waterfall Model
2. Prototype Model
3. Iterative Model and Incremental development Model
4. Rapid application development model
5. Spiral Model
6. Agile Model

1) Waterfall Model :

• Also known as 'classic life cycle model' and 'Linear Sequential Model'.
• This Model suggests a systematic ans sequential approach to software development that begins at requirements analysis and progresses through all life cycle phase sequentially.
• In a waterfall model, each phase must be completed entirely before the next phase can begin. At the end of each phase, a review takes place to determine if the project is on the right path and whether or not to continue or discard the project.
• Development activities carried out sequentially.
• Review and approval of each phase output (Deliverables).

Suitable for project where :

• Requirement and clearly defined.
• Small & Medium term duration.
• Stable Technology.
• Familiarity with the domain and development environments.

Advantages :

• Simple and easy to use.
• Phases and processed and completed one at a time.
• Work well for smaller projects where requirements are very well understood/stable.

Disadvantages :

• It's difficult to respond to changing customer requirements.
• No working software is produced until late during the life cycle.
• Poor model for long run and ongoing projects.

2) Prototype Model :

1. Identify the basic requirement : A prototype is developed based on the initial understanding of the customer requirements.
2. Develop initial prototype : The initial prototype is developed that includes only user interfaces (HTML).
3. Review : The customers, including end users, examine the prototype and provide feedback on additions or changes.
4. Revise and enhance the  prototype : Using the feedback both the specification and the prototype can be improved.

"A visible working prototype helps customer to define the requirements".

Advantages :

• Can be used customer is not sure about what he wants.
• Faster way of finalizing the requirements.
• Useful for new technologies and domains.

for next model click on link : Iterative and Incremental Model