Software Development life cycle models

Source :http://elearning.tvm.tcs.co.in/sdp_html/sdp_waterfall.php

 

In the Industry there are two types of software Development life cycle models:

·         Sequential model

·         Iterative model

Waterfall model / Sequential model

Sequential model represents the development process as a sequence of steps (as phases).

After completion of one phase only the next phase is started

This model is suitable

·         Project size is small

·         All the requirements are freezed in the beginning of project and no changes in the requirements

Prototype

This model approach is develop a sample design based on initial understanding of requirements, present to customer and based on feedback update the design and again present to customer until the requirements are finalized then start development

 There are two types of prototype models

·         Throw away prototype

·         Evolutionary prototype

Spiral Model

This model combines elements of both design and prototyping-in-stages.

This model combines the features of the prototyping and waterfall model.

This model is suitable for large projects and involves new technologies.

ETVX Model

IBM introduced the ETVX model during the 80's to document their processes. 'E' stands for the entry criteria which must be satisfied before a set of tasks can be performed, 'T' is the set of tasks to be performed, 'V' stands for the verification & validation process to ensure that the right tasks are performed, and 'X' stands for the exit criteria or the outputs of the tasks. If an activity fails in the validation check, either corrective action is taken or a rework is ordered. It can be used in any development process. Each phase in the process can be considered as an activity and structured using the ETVX model. If required, the tasks can be further subdivided and each subtask can be further structured using the ETVX model