Software engineering models or sdlc models...

1. SOFTWARE DEVELOPMENT LIFE
CYCLE & ITS MODELS
Presented By:
Asmita Singh

2. List of Contents
1.) SDLC & ITS PHASES
2.) WATERFALL MODEL: ADVANTAGES &
DISADVANTAGES
3.) RAD MODEL: ADVANTAGES & DISADVANTAGES
4.) SPIRAL MODEL
5.) WINWIN SPIRAL MODEL
6.) PROTOTYPE MODEL

3. SDLC
Software Development Life Cycle (SDLC) is a process
used by the software industry to design, develop and
test high quality softwares. The SDLC aims to produce
a high-quality software that meets or exceeds customer
expectations, reaches completion within times and cost
estimates.

5. WATERFALL MODEL
In "The Waterfall" approach, the whole process of software
development is divided into separate phases.It is also referred to
as a linear-sequential life cycle model. The Waterfall model is
the earliest SDLC approach that was used for software
development. It is best suited for those projects in which
requirements are already stated at the very begining of the
project cycle.

7. The sequential phases in Waterfall model are −
Requirement Gathering and analysis − All possible
requirements of the system to be developed are captured
in this phase and documented in a requirement
specification document.
System Design − This system design helps in specifying
hardware and system requirements and helps in defining
the overall system architecture.
Implementation − With inputs from the system design, the
system is first developed in small programs called units,
which are integrated in the next phase.
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8. Integration and Testing − All the units developed in the
implementation phase are integrated into a system after
testing of each unit. .
Deployment of system − Product is deployed in the
customer environment or released into the market.
Maintenance −To enhance the product, some better
versions are released and check regular updates.
Maintenance is done to deliver these changes in the
customer environment.

9. Waterfall Model - Advantages
1.) Simple and easy to understand and use
2.) Phases are processed & completed one at a time.
3.) Works well for smaller projects where requirements
are very well understood
4.) Clearly defined stages.

10. Waterfall Model - Disadvantages
1.) Poor model for long and ongoing projects.
2.) Cannot accommodate changing requirements.
3.) There is no going back on a previous stage due to the waterfall
nature of the model.
4.) Extremely time consuming model
5.) Unable to build a prototype while the lifecyle and hence one has to
wait until the end.

11. RAD Model
Rapid Application Development focuses on gathering customer
requirements through workshops or focus groups, early testing of
the prototypes by the customer using iterative concept, reuse of
the existing prototypes (components), continuous integration and
rapid delivery.
In the RAD model, the functional modules are developed in
parallel as prototypes and are integrated to make the complete
product for faster product delivery.
TEAM + TIME = RAD

13. RAD projects follow iterative and incremental model and have
small teams comprising of developers, domain experts, customer
representatives and other IT resources working progressively on
their component or prototype
Phases of the RAD Model
1.) Business Modeling: A complete business analysis is performed to
find the vital information flow and its processing for business.
2.) Data Modelling: The information gathered in the Business Modeling
phase is reviewed and analyzed to form sets of data objects vital for the
business

14. 3.) Process Modelling: The data object sets defined in the Data
Modeling phase are converted to establish the business
information flow needed to achieve specific business objectives
as per the business model.
4.)Application Generation: final product(app) gets generated and
coded.
5.)Testing & Turnover: The overall testing time is reduced in the
RAD model as the prototypes are independently tested during
every iteration.

15. RAD: Advantages
1.) This model ensures a speedified delivery of the
product
2.) Teams help in parallel functioning of the models
and functional prototypes.
3.) Iteration time can be short with use of powerful
RAD tools.
4.) Encourages customer feedback

16. RAD: Disadvantages
1.) Dependency on technically strong team members for
identifying business requirements.
2.) Inapplicable to cheaper projects as cost of modeling
and automated code generation is very high.

17. Spiral Model
This Spiral model is a combination of iterative
development process model and sequential linear
development model i.e. the waterfall model
Key Feature: Risk Analysis

19. Spiral model consists of six spirals and there are four phases in each
spiral.
The four phases are:
1.) Product Concept
2.) Product Design
3.) Product Testing
4.) Product Delivery
PROS & CONS
PROS:
1.) Customer communication & evaluation is involved at every
stage.
2.) Risk Driven feature curbs and analyze the probable future risks.

20. CONS
1.) A Risk Analyst has to be hired for this model in the company.
2.) It is a time consuming model .
3.) Not suitable for small or low risk projects and could be
expensive for small projects.
WINWIN Spiral Model
In this model, a process of negotiation takes place between the
customer and the developer. the customer wins by getting the
desired functionalities and developer gets satisfied by the desired
cost and budgeting by the customer

21. PROTOTYPE MODEL

22. Thank You