·         The high amount of risk analysis hence, avoidance of possible risk is certainly reduced
·         This model is good for large size and critical projects
·         In the spiral model, additional functionality can be added at a later date

·         It is certainly the costly model to use in terms of development
·         The success of the entire project is dependent on the risk analysis phase thus, failure in this phase may damage entire project
·         It is not appropriate for low-risk projects

2) The waterfall model is one of the most traditional and commonly used software development methodologies for software development.

Advantages of Waterfall Model:

·         Waterfall model is very simple and easy to understand and use a method that is why it is really beneficial for the beginner or novice developer
·         It is easy to manage, because of the rigidity of the model. Moreover, each phase has specific deliverables and individual review process
·         In this model phases are processed and completed are at once in a time thus it saves a significant amount of time

·         This model can only be used when very precise up-front requirements are available
·         This model is not applicable for maintenance type of projects
·         The main drawback of this method is that once an application is in the testing stage, it is not possible to go back and edit something

 3) Agile Software Development is an approach that is used to design a disciplined software management process which also allows some frequent alteration in the development project.

.         Agile methodology has an adaptive approach which is able to respond to the changing requirements of the clients
·         Direct communication and constant feedback from customer representative leave no space for any guesswork in the system

·         This methodology focuses on working software rather than documentation, hence it may result in a lack of documentation
·         The software development project can get off track if the customer is not very clear about the final outcome of his project

The advantages of the waterfall process are that it allows for departmentalization and managerial control. A schedule is typically set with deadlines for each stage of development. The product can proceed through the development process. This process leads to the project being delivered on time because each phase has been planned in detail.

 

Disadvantages 

The disadvantages of waterfall process is cannot be used where the software requirements are likey to change. It also have lots of risks and uncertainty. The working software is produced until very late in this life cycle. It not suitable for complex projects. The process also not real flexibility.

In iterative model we can only create a high-level design of the application before we actually begin to build the product and then define the design solution for the entire product. Later on we can design and built a skeleton version of that, and then evolved the design based on what had been built. We can track the defects at early stages since we are building and improving the product step by step. 

Each of the phase of an iteration is rigid with no overlaps. Costly system architecture or design issues may arise because not all requirements are gathered up front for the entire lifecycle.

It is simple and easy to use. Testing activities, like planning, test designing happens well before coding. This saves a lot of time and has a higher chance of success over waterfall model. V-model can found defects at early stage, avoids the downward flow of the defects and works well for small projects where requirements are easily understood. It is also easy to keep track on the progress.

It is very rigid and least flexible. Software is developed during the implementation phase, so no early prototypes of the software are produced. If any changes happen in midway, the test documents along with requirement documents has to be updated. It is not suitable for bigger and complex projects and the client can see only the final project, not intermediate modules

 

Advantages 

-          Easy to explain to users

Disadvantages

-          Very difficult to go back to any stage after it finished.

 

Advantages 

-          Higher chance of success over the waterfall model due to the development of test plans early on during the life cycle.

Disadvantages

-          Very inflexible, like the waterfall.

 

Advantages 

-          Reduced time and costs, but this can be a disadvantage if the developer loses time in developing the prototypes.

Disadvantages

-          Excessive development time of the prototype.

Advantages 

-          Estimates (i.e. budget, schedule, etc.) become more realistic as work progressed because important issues are discovered earlier.

Disadvantages

-          Needs special skills to evaluate the risks and assumptions.

 

Advantages 

-          More focused on customer value than the linear approaches.

Disadvantages

-          Integration between iteration can be an issue if this is not considered during the development.

Advantages 

-          Face to face communication and continuous inputs from customer representative leaves no space for guesswork.

Disadvantages

-          The ability and collaboration of the customer to express user needs.

 

 

 

Agile development model is also a type of Incremental model. Software is developed in incremental, rapid cycles. This results in small incremental releases with each release building on previous functionality. Each release is thoroughly tested to ensure software quality is maintained.

Advantages: Face-to-face conversation is the form of communication and it is continuous attention to technical excellence and good design.

Disadvantages: There is lack of emphasis on necessary designing and documentation. The project can easily get taken off track if the customer representative is not clear what final outcome that they want.

·         If project is small and easy to understand, V Model is the best approach as its easy and simple to use.

·         Many testing activities are performed in the beginning like planning and design which saves lots of testing time.

·         Most of the defects and bugs are found in the beginning of the project development. So less chances of defect or bug to be occurred at final testing phase.

 

·         Guessing the error in the beginning of the project could take more time.

·         Less flexibility.

·         Any changes done in the middle of the development which is unplanned could make difficult to make the changes at all the places like test document and requirements.

 

Advantage : Risk monitoring is one of the core parts which makes it pretty attractive, especially when you manage large and expensive projects. Moreover, such approach makes your project more transparent because, by design, each spiral must be reviewed and analyzed.

 

Disadvantage : Rules and protocols should be followed properly to effectively implement this model. Doing so, through-out the span of project is tough.
 

 Waterfall Model 

·         Advantage : It is easy to manage, because of the rigidity of the model. Moreover, each phase has specific deliverables and individual review process

·         Disadvantage : The main drawback of this method is that once an application is in the testing stage, it is not possible to go back and edit something

Advantage: Allows for easy testing and analysis.

Disadvantage: No option to know possible outcome of project.

2)      Prototype

Advantage: Gives clear idea about the functional process of the software.

Disadvantages: Chances of extension in management cost.

3)      Agile methodology

Advantage: Adaptive approach that responds to changes favourably.

Disadvantages: Focuses on working with software and lack of documentation efficiency.

4)      Spiral model

Advantage: Allows for additional functionality later.

Disadvantages: Failure in risk analysis phase may damage the whole project.

ADVANTAGES :  Easy to understand and functional.

DISADVANTAGES: Not applicable for maintenance projects.

ADVANTAGES :Adaptive approach that responds to changes favourably.

DISADVANTAGES: Focuses on working with software and lacks documentation efficiency.

ADVANTAGES :  Risk factors are considerably reduced

DISADVANTAGES: Failure in risk analysis phase may damage the whole project.

ADVANTAGES: Proactive defect tracking – that is defects are found at early stage.

DISADVANTAGES: Very rigid and least flexible.

 

 

 

AGILE MODEL

Advantages of Agile model:

RAD MODEL
Advantages of waterfall model:

 

 V model:            
 Advantage
-Testing activities like planning, test designing happens well before coding. This saves a lot time. Hence higher chance of success over the waterfall model

 
Disadvantage
-Very rigid and least flexible

-if any changes happen in midway, then the test documents has to be 

  updated.

 

                                                

 

Advantages

·         It is easy to manage due to the rigidity of the model – each phase has specific deliverables and a review process.

·         Waterfall model works well for smaller projects where requirements are very well understood.

Disadvantages

·         Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.

·         Poor model for long and ongoing projects.

 

ADVANTAGES: in this model, phases are processed and completed one at a time. Moreover, the phases do not overlap.

 

DISADVANTAGES: once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage

 

V-Model

ADVANTAGES: Proactive defect tracking – that is defects are found at early stage.

DISADVANTAGES: Very rigid and least flexible.