Waterfall Model: Definition and Description

P1 and P2 Waterfall Model: 1 Definition: 1 How does it work: 1 Advantages of Waterfall Model: 2 Disadvantages of Waterfall Model: 2 Prototyping models: 2 Definition: 2 Types of prototyping models 2 Bibliography 3 Bibliography 4 Advantages of using prototyping models 4 Disadvantages of using prototyping models 4 Spiral Model: 5 Waterfall Model: Definition: A waterfall model is one the basic and simple Software Development Lifecycle model. Advantages of Waterfall Model: Easy to use Step by step completion of each

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Table of Contents
Waterfall Model:.........................................................................................................................................1
Definition:................................................................................................................................................1
How does it work:....................................................................................................................................1
Advantages of Waterfall Model:..............................................................................................................2
Disadvantages of Waterfall Model:.........................................................................................................2
Prototyping models:....................................................................................................................................2
Definition:................................................................................................................................................2
Types of prototyping models...................................................................................................................2
Bibliography................................................................................................................................................3
Bibliography................................................................................................................................................4
Advantages of using prototyping models................................................................................................4
Disadvantages of using prototyping models............................................................................................4
Spiral Model:...............................................................................................................................................5
Waterfall Model:
Definition:
A waterfall model is one the basic and simple Software Development Lifecycle model. Back in the early
days this model was widely used, but nowadays it is not. Despite not being used much in these days it is
still very important because all other SDLC models are based on it. (htt).
How does it work:
As the name suggests, waterfall, in analogy to a waterfall the steps taken first, or the procedures
followed, cannot be reversed, and each step/phase must be completed before the next one is initiated.

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Advantages of Waterfall Model:
 Easy to use
 Step by step completion of each phase
 The stages are well defined
 The tasks are easily manageable
Disadvantages of Waterfall Model:
 Once the application reaches the state of development, if any errors in the previous steps, you
cannot re do the mistakes.
 A functional software is produced after a long amount of time during the cycle
 There is a relatively huge risk of errors and inconstancy
 It is not suitable for in the long run
 Not applicable for projects where there is a min to max risk of changing requirements
Prototyping models:
Definition:
By the word prototyping we are referring to the act of creating prototypes of a certain application
beforehand to acknowledge any errors or bugs in the app to be created, so it can be fixed before
stepping into development phase. This would also lessen the iterations that may occur while using the
waterfall model.
Types of prototyping models
Throwaway prototyping:
In such case the prototypes are abandoned instead of becoming a part of the software.

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Bibliography
(n.d.). Retrieved from https://www.geeksforgeeks.org/software-engineering-classical-waterfall-model/
(n.d.). Retrieved from https://melsatar.blog/2012/03/15/software-development-life-cycle-models-and-
methodologies/
Evolutionary prototyping:
These are progressed into the final software through a repetitive user feedback.

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Bibliography
(n.d.). Retrieved from https://www.geeksforgeeks.org/software-engineering-classical-waterfall-model/
(n.d.). Retrieved from https://melsatar.blog/2012/03/15/software-development-life-cycle-models-and-
methodologies/
Advantages of using prototyping models
 Time and cost are reduced
 The user is involved more frequently
Disadvantages of using prototyping models
 Inadequate analysis

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 Sometimes the developer cannot completely understand the user requirements and can
sometimes even get them wrong, as to what the user demands.
 Development of the prototype can surprisingly be time consuming
 Implementation of the prototype is not cheap and comes with a heavy cost.
Spiral Model:
Definition:
The spiral model is very much alike to an incremental development towards a system, with more
importance towards risk analysis/assessment. It consists of 4 phases: Planning, Design, Build and Asses.
The software in development must pass through these 4 phases again and again in repetition.
Description:
The spiral model is used mainly as a combination of the prototyping and waterfall model. The spiral
model is used for massive, costly projects. It uses many phases which can also be found in the waterfall
model and particularly in the same order distinguished by planning phase and assessment phase.

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Bibliography
(n.d.). Retrieved from https://www.geeksforgeeks.org/software-engineering-classical-waterfall-model/
(n.d.). Retrieved from https://melsatar.blog/2012/03/15/software-development-life-cycle-models-and-
methodologies/
HOW RISK IS MANAGED IN THESE MODELS:
A risk can be thought of as a chance, although not always meeting the investors requirements. It can be
a deviation from the outcome/result.
Spiral:
The most beneficial part of the spiral model is overcoming the risks or problems after the start of the of
a project. The easiest way to do this is by building a prototype firsthand and then continue forward.
The prototyping model also does supports risk assessment, but the risks need to be distinguished first
then only development can continue, apart from the theory, in everyday life, risks can arise after we
have started development, and in such scenario, it is unfit to use this model (prototype).
In every phase of the spiral model the characteristics of the model are put to date and examined for any
risks, if found the risks are pinpointed and rectified through prototypes. Hence the spiral model is the
most pliable of all the SDLC models.
4 Phases of the spiral model:
1: Determination of objectives and identifying possible solutions: Requirements are collected from
users and the main tasks are pinpointed, explained, and checked at the beginning of each phase, after
this all the possible solutions are noted down.
2: Identify and fix Risks: At this phase, every possible solution is evaluated to filter out the best of these
solutions, after doing so the risks that arise with the selected solutions are resolved using the best
method. As the end of the phase nears, a prototype has been built for the best possible outcome.
3: Create an updated version of the product: During the third phase,

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