Comparison between Spiral model vs Waterfall model

Comparison between Spiral Model vs Waterfall Model

Spiral model vs Waterfall model

The Waterfall and Spiral models are the process models used for developing software in a well-defined, systematic and cost-effective way. Waterfall model is also known as classical or linear model because it follows sequential stages while the spiral model does not follow the sequential stages it follows the evolutionary way. The major difference between these software process models waterfall and the spiral is that the waterfall model is comprised of the separate and isolate phases of specification and development. On the other hand, in a spiral model the different specification, development and validation phases are interleaved.

There are some difference between these two models waterfall and spiral model which are given below:

Sr. No.

Key

Spiral Model

WaterFall Model

1

Definition

Spiral Model is the development model in which the entire model is divided into various sub development phase where corresponding testing phase for each development phase is practices. In other words we can say that for every stage in the development cycle, there is an associated testing phase and corresponding testing phase of the development phase is planned in parallel. On other hand Waterfall model there is first development of the application and after which the different testing of application take place. In other words we can say that in WaterFall the complete process is divided into several phases among which one phase should be completed in order to reach the next phase and testing is almost at end phase of the development.

2

Type/Nature

As mentioned above that in Spiral Model the execution of the phases i.e., development and testing happens in a sequential manner so type of Spiral Model is evolutionary in nature. On other hand WaterFall Model is a relatively linear sequential design approach as each phase should be completed in order to reach the next phase. So type of this model is Continuous in nature.

3

Testing and Validation

In Spiral Model each development phase get tested at its own level and hence no pending testing occurs in this model also if any validation requires to be implemented then it could be implemented at that phase. On other hand in case of WaterFall Model the testing occurs after development is completed and thus if any missing validation is identified to be implemented then first that phase of development needs to be recognized and then that validation get implemented.

4

Cost and Complexity

As sequential phases need to be functional hence the cost is higher as compared to that of WaterFall Model also the complexity is more than WaterFall. On other hand in WaterFall Model due to linear development only one phase of development is operational and hence cost and complexity is low as compared to that of Spiral Model.

5

Simplicity

The waterfall model is simple and easy. The spiral model is a complex model.

6

 Customer Involvement

In spiral model, the customer involvement is high. The customer has an awareness of what the product is. In waterfall model, the customer involvement is minimum.

7

Flow of the Phases

Spiral model operates on iterations so it is possible to go back to the previous phases. In waterfall model, after completing a phase and reached a new phase, it is not possible to go back to the previous phase.

8

Usage

The waterfall model can be used for small projects and for projects with clear requirements. The spiral model can be used for large, complex project that requires continuous risk analyzing.

9

Requirement

Requirements can be added up in the new iterations if required. Needs a thorough understanding of requirements from the beginning.

10

Risk management

Risks are identified and rectified earlier. Risks can only be detected during the completion of the model.

11

Working model of the product

Each iteration produces a working model. Can only be generated in the end.

12

Preferred by

Customers Developers

13

Suitable for

Small systems Large systems

14

Defects

In Spiral Model the probability of total number of defects in the development of application is low as testing is done in parallel to the development. On other hand in WaterFall Model the probability of total number of defects in the development of application is high as testing is done post development.

Summary – Waterfall vs Spiral Model

Two software process models are waterfall and spiral model. The difference between waterfall and spiral model is that waterfall model is used for smaller projects and projects with clear requirements while the spiral model is used for large, complex projects that require continuous risk analyzing.
The spiral model is different from waterfall model due to the feature of definite identification of the risk which reduces the chances of failure of the project. On the other hand, the waterfall is quite risky as there are no iterations everything have to be done at once meaning the requirements are gathered, planned, designed, coded, integrated at one time for a software product.

I hope this post helps you to understand all the comparisons between “Spiral Model and Waterfall Model”.
Keep Learning 🙂

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