Introduction:
SDLC is a process through which a product will be completed or a product will be cleared of any issues. The software development process is described as a series of phases, procedures, and steps that result in complete software. SDLC follows a series of steps that are used to progress the product. It is nothing more than a ladder for managing projects in an organized way. Several different process models are followed today. Some of those are:
(i) Waterfall model
(ii) Spiral Model
(iii)RAD
(iv) Iterative model
(v) Model V
Spiral Model – The spiral model is nothing more than the actual combination of the waterfall model with the risk analysis factor. It follows four phases such as 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 over time we prefer this model. In other words, we can say that RAD is a variation of the prototyping model. But strictly follow the time constraint in each phase for fast project development.
Iterative model: The iterative model is the combination of a mini-waterfall model in each iteration. Although it seems more effective, the time factor, the steps followed and the delay in each phase are important here.
Model V: Model V is the classic model of software development. It encapsulates the steps in the Verification and Validation phases for each step in the SDLC. For each phase, the subsequent phase becomes the Verification (QA) phase, and the corresponding Test phase on the other arm of the V becomes the Validation (Test) phase.
Waterfall model:
In addition to these well-known models, the software industry uses several other models depending on the size, time, and budget of the project. Here I take a look at the well-known Waterfall model. It is a unique model that is followed by most companies. In fact, certain features of Waterfall entice top executives to adapt it. Some of the unique features are:
1. It can be implemented for projects of all sizes.
2. It leads to a clear and concrete approach to software development.
3. In this model, the test is inherent to each phase.
4. Documentation occurs at each stage of the model, which is very helpful for the people involved.
There are several phases that can be maintained in the Waterfall model:
(i) Preliminary investigation and feasibility analysis.
(ii) Analysis of requirements
(iii) System design
(iv) Encoding
(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]
(Diagram of the waterfall model)
One important thing about the waterfall model is that at each phase a conscious decision is made to continue with the project or to stop it.
Phase 1–> Preliminary investigation:
It is the initial phase of the project. It’s actually the job of top executives. The objective of this phase is not to develop the system but to investigate the problem or make decisions for new requirements. When executives make decisions about a project, they take into consideration several factors, such as technology, time, budget…
When agreement to proceed with the project has been made, the second phase of the SDLC is implemented.
Phase2–> Requirements analysis:
This phase deals with gathering system requirements. This phase is also known as the data collection phase. This process consists of generating a review of documents and requirements. The result of this phase is a formal requirements document, that is, the software requirements specification.
Phase3–>System design:
Taking the requirements into account, the system specifications are translated into 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 come first: input, output, processing, and files. The designer is responsible for all these things. System design is nothing more than a platform for how well a programmer codes. The design phase leads to a result for the next phase, that is, formal requirements statements.
Phase4–>Coding:
In this phase, the programmer begins his coding to give a complete sketch of the product. In other words, the system specifications are only converted into machine-readable computer code. But sometimes it’s hard for coding people to maintain the design, so the requirements statement needs to be examined and re-examined. Whenever there are deviations, they will always be approved either by the PL or by the Client.
Phase5–>Integration and Testing:
In this phase, all programs (models) are integrated and tested to ensure that the entire system meets the software requirements. Testing is all about verification and validation. Apart from this, unit and integration tests are done to test all the classes and functions etc. Integration testing is done by including a unit together with another unit and testing them as a whole.
Phase6–>Implementation and Maintenance:
The implementation phase involves the actual coding or programming of the software. The output of this phase is usually 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:
-Satisfy the changing needs of the client.
– Adapt to adapt to changes in the external environment.
-correct errors and oversights not previously detected in the testing phase.
-Improve the efficiency of the software.
Conclusion:
In conclusion, I would prefer to say that the Waterfall Model is a well-organized, document-based process model that will lead to concrete, more secure and reliable software.