Software Development Life Cycle Models

Software Development Life Cycle Models

Waterfall Model

Description

The waterfall Model is a linear sequential flow. In which progress is seen as flowing steadily downwards (like a waterfall) through the phases of software implementation. This means that any phase in the development process begins only if the previous phase is complete. The waterfall approach does not define the process to go back to the previous phase to handle changes in requirement. The waterfall approach is the earliest approach that was used for software development.

Advantages

Disadvantages

· Easy to explain to the user                                       · Structures approach.                                               · Stages and activities are well defined                        · Helps to plan and schedule the project                     · Verification at each stage ensures early detection of errors / misunderstanding                                            · Each phase has specific deliverables

· Assumes that the requirements of a system can be frozen                                                                       · Very difficult to go back to any stage after it              finished                                                                     .· Little flexibility and adjusting scope is difficult and expensive                                                                 .· Costly and required more time, in addition to detailed plan

 

V-Shaped Model

Description

It is an extension for waterfall model, Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the typical V shape. The major difference between v-shaped model and waterfall model is the early test planning in v-shaped model.

The usage

· Software requirements clearly defined and known
· Software development technologies and tools is well-known

Advantages

Disadvantages

· Simple and easy to use.                                            · Each phase has specific deliverables                         .· Higher chance of success over the waterfall model due to the development of test plans early on during the life cycle.                                                                        · Works well for where requirements are easily understood.

· Very inflexible, like the waterfall model.                    · Little flexibility and adjusting scope is difficult and expensive.                                                                 · Software is developed during the implementation phase, so no early prototypes of the software are produced.                                                                 · Model doesn’t provide a clear path for problems found during testing phases.                                       · Costly and required more time, in addition to detailed plan