Topic: SDLC and STLC

Verification

 

Verification is the process to ensure that the design outputs of particular phase of the SDLC meet all specified requirements for that phase. Verification is also known as In-Process Testing. Verification typically involves reviews and meeting s to evaluate documents, plans, code, requirements and specifications. It determines consistency, correctness and completeness of a program at each stage.

 

Validation

 

Validation is the process to test whether the product meets the customer requirements in the intended environment. Validation is also known as Exit or End Process Testing. Validation involves actual testing and takes place after the verification are complete. It determines the correctness of final build with respect to its requirements.

 

Verification is the checking or testing of items, including software, for conformance and consistency with an associated specification. Validation is the process of checking that what has been specified is what the user actually wanted.

Validation: Are we building the right product?

Verification: Are we building the product right? 

The software development lifecycle begins with the identification of a requirement for software and ends with the formal verification of the developed software against that requirement. Traditionally, the models used for the software development lifecycle have been sequential, with the development progressing through a number of well defined phases. The sequential phases are usually represented by a V or waterfall diagram. Extension of V model is W Model, which is also known as verification and validation (VnV) model.

Another important purpose of testing is verification and validation (V&V). Testing can serve as metrics. It is heavily used as a tool in the V&V process. Testers can make claims based on interpretations of the testing results, which either the product works under certain situations, or it does not work. We can also compare the quality among different products under the same specification, based on results from the same test.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Waterfall Model

 

In this model the development process is divided into separate and distinct stages. The output of each stage becomes input to the next stage and this process carries on sequentially till end of the process. In this model, the software development process is divided into five stages:

 

-          Requirements Specifications (Outputs – SRS Document, Test Strategy document)

-          System Design and Software Design (Outputs – HLD, LLD, Test Plan)

-          Implementation and Unit Testing

-          Integration and System Testing

-          Operation and Maintenance

 

This model is to be used when SRS is clear. It is simple and effective model for commercial projects with clear requirements. Project monitoring is effective as defined outputs are available at the end of each stage.

 

V Model

 

This process model is similar to Waterfall model, and gives high importance to testing, applicable at every stage of software development process. The V-model contains parallel testing phases for all the development phases. The four main process phases – user requirements, functional specification, technical design and program implementation; have a corresponding verification and validation-testing phase. Implementation of modules is tested by unit testing, technical design is validated by integration testing, functional specifications are verified by system testing and acceptance testing verifies the requirements.

 

Edited by Mithi25 - 02Aug2009 at 11:16pm