What is Waterfall Model design?
Waterfall approach
was first SDLC Model to be used widely in Software Engineering to ensure
success of the project. In "The Waterfall" approach, the whole
process of software development is divided into separate phases. In Waterfall
model, typically, the outcome of one phase acts as the input for the next phase
sequentially.
Following is a
diagrammatic representation of different phases of waterfall model.
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 doc.
·
System Design: The requirement specifications
from first phase are studied in this phase and system design is prepared.
System Design helps in specifying hardware and system requirements and also
helps in defining overall system architecture.
·
Implementation: With inputs from system design,
the system is first developed in small programs called units, which are
integrated in the next phase. Each unit is developed and tested for its
functionality which is referred to as Unit Testing.
·
Integration and Testing: All the units
developed in the implementation phase are integrated into a system after
testing of each unit. Post integration the entire system is tested for any
faults and failures.
·
Deployment of system: Once the
functional and non functional testing is done, the product is deployed in the
customer environment or released into the market.
·
Maintenance: There are some issues which come
up in the client environment. To fix those issues patches are released. Also to
enhance the product some better versions are released. Maintenance is done to
deliver these changes in the customer environment.
All these phases are
cascaded to each other in which progress is seen as flowing steadily downwards
(like a waterfall) through the phases. The next phase is started only after the
defined set of goals are achieved for previous phase and it is signed off, so
the name "Waterfall Model". In this model phases do not overlap.
Waterfall Model Application
Every software
developed is different and requires a suitable SDLC approach to be followed
based on the internal and external factors. Some situations where the use of
Waterfall model is most appropriate are:
·
Requirements are very well documented, clear and fixed.
·
Product definition is stable.
·
Technology is understood and is not dynamic.
·
There are no ambiguous requirements.
·
Ample resources with required expertise are available to support the
product.
·
The project is short.
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