Introduction: SDLC is a process through which a product will get completed or a product get rid from any problem. Software development process is described as a number of phases, procedures and steps that gives the complete software. SDLC follows series of steps which is used for product progress. It is nothing but a ladder for project management in an organized manner. Now-a-days a number of different process models are followed. Some of those are:
(i)Waterfall Model
(ii)Spiral Model
(iii)RAD
(iv)Iterative Model
(v)V-Model
Spiral Model: Spiral model is nothing but the royal combination of Waterfall Model with Risk Analysis factor. It follows four phases like planning, Risk Analysis, Engineering and Evaluation. In large projects this model is preferable.
RAD: RAD or Rapid Application Development explains the model itself. For rapid development of projects in time we prefer this model. In other words we can say RAD is a variation of the Prototyping Model. But it strictly follows time constraint on each phase for quick development of project.
Iterative Model: Iterative Model is the combination some mini-Waterfall Model in each iteration. Though it is looking more effective but the time factor, steps followed and delay in each phase matters here.
V-Model: V model is the classic software development model. It encapsulates the steps in Verification and Validation phases for each step in the SDLC. For each phase, the subsequent phase becomes the verification (QA) phase and the corresponding testing phase in the other arm of the V becomes the validating (Testing) phase.
Waterfall Model:
Apart from these known models there are several other models are used by the software industry depending on the project size, time and budget. Here I put a glance on well known Waterfall model. It is a unique model which is followed by most of the companies. In fact certain features of Waterfall attracts the top executives to adapt it. Some of the unique features are:
1.It can be implemented for all size project.
2.It leads to a concrete and clear approach to software development.
3.In this model testing is inherent in every phase.
4.Documentation is produced at every stage of model which is very helpful for people who are involved.
There are various phases can be maintained in Waterfall model:
(i)Preliminary investigation and feasibility analysis.
(ii)Requirement Analysis
(iii)System design
(iv)Coding
(v)Integration and testing
(vi)Implementation and maintenance
[Preliminary Investigation]
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[Requirement Analysis]
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[System Design]
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[Coding]
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[Integration & Testing]
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[Implementation & Maintenance]
(Waterfall Model Diagram)
One important thing of the Waterfall Model is that at each phase a conscious decision is taken whether to continue the project or to stop it.
Phase1--> Preliminary Investigation:
It is the starting phase of project. Actually it is the job of top executives. The aim of this phase is not develop system but to investigate the problem or to take decision for new requirements. When the executives are taking decisions on a project they take various factors in to consideration, like Technology, Time, Budget.. When the agreement has been made to continue with the project the second phase of the SDLC is implemented.
Phase2--> Requirement Analysis:
This phase is concerned about collection of requirement of the system. This phase is otherwise known as Data gathering phase. This process involves to generate document and requirement review. The output of this phase is a formal requirements document i.e software requirement specification.
Phase3-->System Design:
Keeping the requirements in mind the system specifications are translated in to a software representation. In this phase the designer emphasizes on
i)Algorithm
ii)Data structure
iii)Software Architecture
iv)Interface design
In this phase various components always comes first those are input, output, processing and files. Designer is responsible for all these things. The system design is nothing but a platform for how well a programmer code. The design phase leads to an output for the next phase i.e Formal Requirement Statements.
Phase4-->Coding:
In this phase programmer starts his coding in order to give a full sketch of product. In other words system specifications are only converted in to machine readable compute code. But sometimes it is tough for coding people to maintain the design .So for that reason examination and re-examination of the requirement statement is necessary. Whenever any deviations, would always approved either by the PL or by the Client.
Phase5-->Integration & Testing:
In this phase all programs(models) are integrated and tested to ensure that the complete system meet the software requirements. The testing is concerned with verification and validation. Apart from this Unit testing and Integration testing is done in order to test all classes and functions etc. Integration testing is done by including unit together with other unit and testing them whole.
Phase6-->Implementation & Maintenance:
The implementation phase involves the actual coding or programming of the software. The output of this phase is typically the library, executables , user manuals and additional software documentation. The maintenance phase is the longest phase of the SDLC. In this phase the software is updated to:
-fulfill the changing customer need
-adapt to accommodate change in the external environment
-correct errors and oversights previously undetected in the testing phase.
-enhance the efficiency of the software.
Conclusion:
In conclusion i will prefer to say Waterfall Model is a document driven and well organized process model which will lead to a concrete , more secured and reliable software.