Spiral Model
Why Spiral Model came into existence?
It came into existence for mission critical projects, where the risk factor was to be evaluated. Used in Mission Critical System such as guided missile systems.
Risk Analysis
Critical Software
Risk
Trigger Event
Monitor
Manage
Engineering
Design
Develop
Integration and Testing
While drawing the life cycle, draw it segment by segment.
The spiral model, originally proposed by Boehm is an evolutionary software process model that couples the iterative nature of prototyping with the controlled and systematic aspects of the linear sequential model.
It provides the potential for rapid development of incremental versions of the software. Using the spiral model, software is developed in a series of incremental releases. During early iterations, the incremental release might be a paper model or prototype. During later iterations, increasingly more complete versions of the engineered system are produced.
The spiral model is intended for large, expensive, risky and complicated projects. For larger, more critical projects, each task region contains more work tasks that are defined to achieve a higher level of formality.
Spiral model that contains six task regions:
• Planning—tasks required to define resources, timelines, and other project related information.
• Risk analysis—tasks required to assess both technical and management risks.
• Engineering—tasks required to design, develop, integrate and test.
• Customer evaluation—tasks required to obtain customer feedback based on evaluation of the software representations created during the engineering stage and implemented during the installation stage.
Advantages:
1. Best for development of Critical applications.
2. Software build is robust in nature.
3. Can cope with the changes in the requirements.
Drawbacks:
1. Time increases.
2. Cost increases, as a new phase is added in the life cycle.
RAD Model
Rapid application development (RAD), follows the water fall model itself. Each of the phase of the waterfall model is mapped with the automation tool. RAD is designed to take advantage of powerful development software like CASE (Computer Aided Software Engineering) tools, prototyping tools and code generators (MS Visual Studio, MS Front Page) it is described as a process through which the development cycle of an application is expedited. Rapid Application Development thus enables quality products to be developed in a very short span.
Phase Tool
1. Project Management Project Console
2. Requirements Gathering Requisite Pro
3. Design and Development Rational Rose
4. Test Management QTP, QC, WR
Advantages.
1. Product is operational very soon.
2. Emphasizes on extremely short development life cycle.
3. Requirements are well understood.
4. Creates a fully functional system in a very short span.
5. Component based construction.
Disadvantages
1. High cost to buy the licenses of the RAD tools
Some of these tools costs 10 cr. Client is not going to buy these expensive tools right.
V MODEL
What was the need of V model?
In earlier SDLC models defects were discovered very late in the life cycle. Necessity is the mother of invention. Right!!!
What it is?
Implements the waterfall model. Testing is done very early in the Life cycle. V model emphasis on early discovery of defects, and eventually brings down the cost.
Requirements 1 <-------------------------------------------> 2 Acceptance Test cases
High Level Design 3 <------------------------------> 4 System Test cases
Low Level Design 5 <-----------------------> 6 Integration Test cases
Unit Level Design 7 <----------> 8 Unit Test cases
9 Code
The ‘V’ can also stand for the terms Verification and Validation.
Advantages:
1. The errors of the particular phases are identified in that particular phase only. So stops the propagation of defect to another phase. Prevents defect multiplication.
2. Optimization of the test resources i.e. the testers.
3. Relative reduction on cost compared to the other SDLC models.
4. Starting early means the duration of the life cycle is reduced.
5. Testing activities like test designing start at the beginning of the project well before coding and therefore saves a huge amount of the project time.
Verification and Validation model à V and V model à V model
Some computer illiterates also call it as V shaped model
Why Spiral Model came into existence?
It came into existence for mission critical projects, where the risk factor was to be evaluated. Used in Mission Critical System such as guided missile systems.
Risk Analysis
Critical Software
Risk
Trigger Event
Monitor
Manage
Engineering
Design
Develop
Integration and Testing
While drawing the life cycle, draw it segment by segment.
The spiral model, originally proposed by Boehm is an evolutionary software process model that couples the iterative nature of prototyping with the controlled and systematic aspects of the linear sequential model.
It provides the potential for rapid development of incremental versions of the software. Using the spiral model, software is developed in a series of incremental releases. During early iterations, the incremental release might be a paper model or prototype. During later iterations, increasingly more complete versions of the engineered system are produced.
The spiral model is intended for large, expensive, risky and complicated projects. For larger, more critical projects, each task region contains more work tasks that are defined to achieve a higher level of formality.
Spiral model that contains six task regions:
• Planning—tasks required to define resources, timelines, and other project related information.
• Risk analysis—tasks required to assess both technical and management risks.
• Engineering—tasks required to design, develop, integrate and test.
• Customer evaluation—tasks required to obtain customer feedback based on evaluation of the software representations created during the engineering stage and implemented during the installation stage.
Advantages:
1. Best for development of Critical applications.
2. Software build is robust in nature.
3. Can cope with the changes in the requirements.
Drawbacks:
1. Time increases.
2. Cost increases, as a new phase is added in the life cycle.
RAD Model
Rapid application development (RAD), follows the water fall model itself. Each of the phase of the waterfall model is mapped with the automation tool. RAD is designed to take advantage of powerful development software like CASE (Computer Aided Software Engineering) tools, prototyping tools and code generators (MS Visual Studio, MS Front Page) it is described as a process through which the development cycle of an application is expedited. Rapid Application Development thus enables quality products to be developed in a very short span.
Phase Tool
1. Project Management Project Console
2. Requirements Gathering Requisite Pro
3. Design and Development Rational Rose
4. Test Management QTP, QC, WR
Advantages.
1. Product is operational very soon.
2. Emphasizes on extremely short development life cycle.
3. Requirements are well understood.
4. Creates a fully functional system in a very short span.
5. Component based construction.
Disadvantages
1. High cost to buy the licenses of the RAD tools
Some of these tools costs 10 cr. Client is not going to buy these expensive tools right.
V MODEL
What was the need of V model?
In earlier SDLC models defects were discovered very late in the life cycle. Necessity is the mother of invention. Right!!!
What it is?
Implements the waterfall model. Testing is done very early in the Life cycle. V model emphasis on early discovery of defects, and eventually brings down the cost.
Requirements 1 <-------------------------------------------> 2 Acceptance Test cases
High Level Design 3 <------------------------------> 4 System Test cases
Low Level Design 5 <-----------------------> 6 Integration Test cases
Unit Level Design 7 <----------> 8 Unit Test cases
9 Code
The ‘V’ can also stand for the terms Verification and Validation.
Advantages:
1. The errors of the particular phases are identified in that particular phase only. So stops the propagation of defect to another phase. Prevents defect multiplication.
2. Optimization of the test resources i.e. the testers.
3. Relative reduction on cost compared to the other SDLC models.
4. Starting early means the duration of the life cycle is reduced.
5. Testing activities like test designing start at the beginning of the project well before coding and therefore saves a huge amount of the project time.
Verification and Validation model à V and V model à V model
Some computer illiterates also call it as V shaped model
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