Software Engineering - Waterfall Model

1. Software Engineering
Waterfall model
Prof. Navya Francis
Asst. Professor
Kristu Jayanti College

2. Software Development Life Cycle (SDLC)

3. 1. Waterfall Model
2. Prototype Model
3. Rapid application development Model
4. Evolutionary Model
5. Incremental Model
6. Iterative Model
7. Component based software engineering
8. Spiral Model
Process Models

4. WATERFALL
MODEL

5. WATERFALL
MODEL
The Waterfall Model was the first Process Model to be introduced.
It was developed by Royce, 1970
It is also referred to as a linear-sequential life cycle model or software life cycle.
It is very simple to understand and use.
In a waterfall model, each phase must be completed before the next phase can begin
and there is no overlapping in the phases.

6. DIFFERENT
STAGES OF
WATERFALL
MODEL

7. 1. REQUIREMENTS ANALYSIS AND DEFINITION
• The system’s services, constraints and goals are established by
consultation with system users.
• They are then defined in detail and serve as a system
specification.

8. 2. SYSTEM AND SOFTWARE DESIGN
The systems design process
partitions the requirements to
either hardware or software
systems.
It establishes an overall
system architecture.
Software design involves identifying
and describing the fundamental
software system abstractions and
their relationships

9. 3. IMPLEMENTATION AND UNIT TESTING
During this stage, the software design is realised
as a set of programs or program units.
Unit testing involves verifying that each unit
meets its specification.

10. 4. INTEGRATION AND SYSTEM TESTING
The individual program units or programs are
integrated and tested as a complete system
to ensure that the software requirements
have been met.
After testing, the software system is
delivered to the customer.

11. 5. OPERATION AND MAINTENANCE
Normally (although
not necessarily) this is
the longest life-cycle
phase.
The system is installed
and put into practical
use.
Maintenance involves
correcting errors
which were not
discovered in earlier
stages of the life cycle,
improving the
implementation of
system units and
enhancing the
system’s services as
new requirements are
discovered.

12. Advantages of Waterfall Model
ADVANTAGES
ADVANTAGES
• Easy to understand and implement.
• Widely used and known.
• Identifies deliverables and milestones.
• It redeems the software development process of the code and fix problems.
• Main strength lies in the fact that it emphasizes the software development
process must be planned and well managed.
• It allows for communication between the customer and developer and specifies
what will be delivered.

13. Disadvantages of Waterfall Model
DISADVANTAGES
• Cannot accommodate changing requirements.
• Model is rigid
• High amounts of risk and uncertainty.
• Huge gap in-between phases and there is no way to cross check
user requirements.
• Not a good model for complex and object-oriented projects.
• Adjusting scope during the life cycle can end a project.

14. Where to use waterfall model?
When to use
WATERFALL
MODEL
• Requirements are very well known, clear and fixed.
• Product definition is stable.
• Technology is understood.
• There are no ambiguous requirements.
• Ample resources with required expertise are available.
• The project is small

15. THANK YOU