Classic Waterfall model in Software Engineering
Summary
TLDRIn this educational video, the classical waterfall model in software development is explained, highlighting its linear, sequential phases: feasibility study, requirement analysis, design, coding, testing, and maintenance. The video emphasizes its simplicity and suitability for small projects with fixed requirements. However, it also points out its rigidity, lack of flexibility, absence of parallelism, and high risk due to late feedback, often resulting in a significant maintenance phase where most issues are addressed.
Takeaways
- đ Classical Waterfall model was introduced in the 1970s and is a very old model.
- đ It is called a 'waterfall' because the steps are sequential, like a waterfall.
- đ The model includes phases such as feasibility study, requirement analysis, design, coding, testing, and maintenance.
- đ Feasibility study ensures the project is viable technically and financially.
- đ Maintenance is the most important phase as it requires around 60% of the effort.
- đ The Waterfall model is rigid; once a phase is completed, it cannot be revisited.
- đ It works well for small projects where the customer's requirements are clear and fixed.
- đ Lack of feedback between phases is a major disadvantage of the model.
- đ There is no parallelism, meaning one phase must be completed before the next can start.
- đ High risk is associated with the Waterfall model because issues are only identified in the final stages.
Q & A
What is the classical waterfall model?
-The classical waterfall model is an old software development model from the 1970s, characterized by a linear and sequential approach where each phase must be completed before the next one begins.
Why is it called the 'waterfall' model?
-It is called the 'waterfall' model because the phases in the process are depicted in a diagram that resembles a waterfall, flowing in a systematic way from one phase to the next without looping back.
What are the main phases of the classical waterfall model?
-The main phases of the classical waterfall model include feasibility study, requirement analysis, specification design, coding and unit testing, system testing and integration, and maintenance.
What is the purpose of the feasibility study in the waterfall model?
-The feasibility study determines whether a project is feasible, considering technical and financial aspects, ensuring that the project can be completed within the given budget and resources.
Why is the waterfall model considered rigid?
-The waterfall model is considered rigid because it does not allow for changes once a phase is completed and the process moves to the next phase, lacking flexibility and feedback mechanisms.
What are the advantages of using the classical waterfall model?
-The advantages of the classical waterfall model include its simplicity, systematic approach, and suitability for small projects with clear and fixed requirements.
What are the disadvantages of the classical waterfall model?
-The disadvantages include its rigidity, lack of flexibility, absence of parallelism, high risk due to the late identification of issues, and the need for a significant amount of effort in the maintenance phase.
Why is the maintenance phase considered very important in the waterfall model?
-The maintenance phase is crucial because it is where most of the effort (up to 60%) is spent fixing problems and bugs that were not identified in earlier phases due to the model's rigidity.
How does the waterfall model handle changes in requirements?
-The waterfall model does not handle changes in requirements well, as it is designed to move forward through phases without looping back, making it difficult to incorporate changes after the initial requirements phase.
What is an example given in the script to illustrate the problems with the waterfall model?
-The script uses the example of building a dream house where the customer does not see the progress until the end, leading to late discovery of issues like a small kitchen or misplaced bedroom, which then require costly and time-consuming changes during the maintenance phase.
Outlines
đ» Introduction to the Classical Waterfall Model
The video begins with an introduction to the Classical Waterfall Model, a traditional software development approach dating back to the 1970s. The presenter outlines the various phases of the model, including feasibility study, requirement analysis, specification design, coding and unit testing, system testing and integration, and maintenance. The video emphasizes the importance of each phase, using examples to illustrate the process. The presenter also discusses the model's advantages, such as its systematic and straightforward nature, which makes it suitable for small projects with clear and unchanging requirements. However, the rigidity of the model is highlighted as a significant disadvantage, as it lacks flexibility and does not accommodate feedback or changes once a phase is completed.
đ§ Disadvantages and Risks of the Classical Waterfall Model
In the second paragraph, the presenter delves into the disadvantages and risks associated with the Classical Waterfall Model. The rigidity of the model is critiqued for not allowing for changes or parallel work, which can lead to inefficiencies and idle resources. The lack of feedback and the inability to incorporate new experiments or ideas during the development process are also highlighted as major drawbacks. The presenter uses the analogy of building a dream house to illustrate the high risk and potential for costly mistakes when problems are only discovered in the final phase. The video concludes with a discussion on the significant effort and resources often required in the maintenance phase due to the model's inflexibility, which can lead to wasted time and additional costs.
Mindmap
Keywords
đĄClassical Waterfall Model
đĄFeasibility Study
đĄRequirement Analysis
đĄSpecification Design
đĄCoding and Unit Testing
đĄSystem Testing and Integration
đĄMaintenance
đĄRigidity
đĄParallelism
đĄRisk
đĄFeedback System
Highlights
Introduction to the classical waterfall model.
The classical waterfall model originated in the 1970s.
The model is often used for small projects due to its simplicity.
The waterfall model is visually represented as a series of steps, like a waterfall.
Phases of the waterfall model include feasibility study, requirement analysis, design, coding, testing, and maintenance.
Feasibility study determines if a project is technically and financially viable.
Requirement analysis and specification involve understanding and documenting customer needs.
Design phase lays out the blueprint for the software development.
Coding and unit testing involve implementing the software and testing individual components.
System testing and integration ensure that all parts of the software work together.
Maintenance is a critical phase where most of the effort is spent fixing bugs and issues.
The waterfall model is advantageous for its simplicity and systematic approach.
It is a rigid model with no flexibility for changes once a phase is completed.
Lack of feedback and parallelism can lead to high risk and potential for errors.
The model is not suitable for projects with evolving requirements.
A real-life analogy compares the waterfall model to building a house without the ability to make changes during construction.
The importance of the maintenance phase, where most of the effort is spent addressing issues.
The classical waterfall model is foundational, serving as a base for other software development models.
Transcripts
Dear students welcome to Gate Smashers
In this video I'm going to explain what is classical waterfall model
And all the related points to it
Advantages disadvantages
I will explain each and every fact with example in this video
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So first of all we will start
Over here classical waterfall model
It came at the time of 1970s it is a very old model
Practically if you talk about software development
I don't think so anyone might have used it more
Maybe it might have been used for small projects
Because why it is actually called waterfall
See and waterfall steps are like this in a systematic way
And you can see this diagram like waterfall
Now look the steps in this
Feasibility study is there
Work is the same
We had discussed in SDLC
All the phases that are there in software development life cycle
All that phases are only there
Even if you talk about prototype model spiral model
Are you talk about waterfall
No matter you talk about which model
But all the main points in this
That I'm actually telling you
Look feasibility studies their requirement analysis is there
Specification design is there
Coding and unit testing is there
System testing and integration
And finally we have maintenance
If we talk about feasibility study
What is the meaning of feasibility study
That whether your project is feasible or not
If we talk technically
Are you talk financially
Then whether it is feasible or not
It is not that you have taken such a big project
And your budget is very less
And the project should be technically so sound that
That's somewhere a platform and a team should be available
So first of all we will check that whether it is feasible
Can you make it in that much money
When all that thing will be gathered
And you will go and requirement analysis and specifications
You have checked it
After that what you have finalized
That how much team will I require
How much time will I need you will do the estimation
And you will prepare SRS document over here
So that you can give all the specification in written to your customer
Then we have designing phase
Coding and unit testing
Coding is the same implementation
After that unit testing
You are testing each and every small unit
System testing and integration
You have integrated small units
After that you did system testing
Alpha testing is there beta testing is there
Acceptance testing is there
Later on you will get each and every point
But what happens is in unit testing first to tested each and every unit
After that when you combined all the modules and the system was big
So after integrating it
Alpha testing which is done by the team that is developing it
Beta testing is done by your friendly customer
Acceptance means after checking properly customer will tell whether he will accept this
Or I will not accept this software
And finally comes maintenance
This is a very very important phase
In this
In this the maintenance phase is very important because
Because Sir maximum 60% effort is on maintenance phase only
Why is it so that you will come to know now
What is the meaning of maintenance phase
If any problem comes or any bug comes
You have to fix it
Each and every whatever problem is coming technical or non technical
You have to fix all of them
So look over here
If you talk about its advantages
What are advantages of this model
It is a basic model
It is a very basic model so whichever later on model
Somewhere it is working like a base for them
That means it was the first model
It will tell you that this is the story
Letter on they have removed its problems
So it works like a base
Let us simple it is easy there is no long story in it
Your steps are mentioned in a systematic way
You can say it is easy for small projects
Where all the requirements of customer
He clearly knows
First customer has given a requirement and after that he makes changes in that
No whatever he has told once that is fixed
That is why this model is a bit rigid
There is no flexibility
It is rigid
Why is it rigid? Okay it is an advantage for small projects
But what is the big disadvantage over here
What is your project
Whatever you have told once to your service provider
That I want this
When he has started working
After that you don't have any role
Your role will start when you will get the project
Whatever problem, bugs, issues will come
That will be removed in this phase
That means what is the biggest and major problem over here
There is no feedback
What is not there? Feedbacks are not there
That means whatever work you have done over here you have handed it over to the next team
Then you handed it to next team
Now if anyone feels in between that there is some problem
I should tell to the previous team
That rectify it a bit
No it is not there
The model is very rigid it tells I'm not going to do any changes
Once what is done in one phase
Then it will go in next phase only
No value will go in back phase
Then if you talk about experiments
It is the same thing that you cannot do any changes
Or you cannot bring any new experiment over here
Whatever the previous team has done that only you will have to carry forward
You have to submit it to the next to the next in this way you have to work
There is no parallelism
What is the meaning of parallelism
That at a time multiple teams can work
No
Over here it is not so first this team will work
Other teams are sitting idle
When this team has got work other teams are sitting idle
When he has got to work others are sitting idle
That means parallelism is not there
At a time you are not doing multiple work
High risk is there obviously there will be high risk
Because rigidity is there
Over here flexibility is not there
So risk will be there
Why? Because all the problem that is occurring
That all you will be able to see in the last phase
If I tell you this with our simple and real life example
You want to make your dream house
You took land
You got a map prepared from an architect
Each and everything is done
You have also given money to the builder
Builder has built the house
That means the time from which you purchased your house till your grah privesh
You have not seen what is going on how is it going on
When you have to go inside the house
Then you saw that here is the mistake
Kitchen is very small
Bedroom should not have been over here, it should have been over here
I want to do this, now if you will do changes
Batman's your directly doing this change in maintenance phase
That means you have entered the house and along with that you have also started breaking it
Sometimes you will break here, sometimes you will do this
So obviously it is such a big problem
It's better that you have a feedback system in between only
If there is any mistake
If there is any problem
We can remove it in that phase only
In that phase only we can fix bugs
This thing is missing over here
That is why 60% effort is there in maintenance phase only
Because other phases have done their work and are sitting relaxed
They know that whatever problem will come, it will come in maintenance phase and at that time we will solve it
Maintenance again and again you will have bugs and problems
Because actually when the customer got the software and he has given to his users ahead
At that time all the problems will occur
And then you will slowly try to remove them
So somewhere your time will also be wasted
Obviously you will require extra money also
So these are the major problems over here
In classical waterfall model
There is nothing in it other than this
No matter whatever they ask you
If you have told these points
This is more than sufficient
Thank you
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