Waterfall Model
The waterfall model is the simplest and most popular system development life cycle model for software engineering. In this model, each phase is organized in linear and sequential order. Once a phase is completed, one can then proceed to the development of the next phase. It must be noted however, that once a stage is completed, there is no turning back. The stages in the waterfall life cycle modal are as follows:
• Requirements Analysis
• Requirements Specification
• System Design
• Code and test
• Implementation
• Maintenance
Waterfall Life Cycle Model
The advantages of the waterfall Model are:
• One stage must be 100% complete before moving on.
• Each stage relies on the information from the previous stage only.
• There is a lot of documentation.
• There is a specialist at each stage.
• There is a project plan for each stage.
• There is also accountability for each stage.
The disadvantages of the Waterfall Model are:
• There is little user involvement.
• Time delay in the early stages will cause delays in the later stages.
• Errors cannot be rectified until it reaches the maintenance stage.
• It is not a true reflection of the real world since some stages can be done in parallel.
• Very little testing is done.
Prototype Life Cycle Model
Prototyping entails building a simplified subset of the proposed system that simulates the actual processing that will be carried out by the real system (Sommerville, 2000). Basically, it consists of a few screen designs and reports that provide just significant functionality to allow users to experience how the proposed system might look and feel. There are two type of prototyping, throw away and evolutionary. Throw away prototyping entails the creation of a model that will eventually be discarded and one that will not be part of the final system. Evolutionary on the other hand consists of constructing a strong system in