Software engineering is an engineering discipline that applies scientific principles and methods to the development of software. It aims to deliver reliable and efficient software on time and within budget by defining processes and procedures. The need for software engineering has arisen due to factors like increasing changes in user requirements and environments, large and complex software projects, ensuring scalability and cost-effectiveness, and managing quality.

1. INTRODUCTION
Software engineering is an engineering branch associated with
development of software product using well-defined scientific
principles, methods and procedures. The outcome of software
engineering is an efficient and reliable software product.
Software engineering may also be defined as “A discipline whose
aim is the production of quality software, software that is
delivered on time within budget and that satisfies its
requirements.”

2. WHY DO WE NEED IT?
The need of software engineering arises because of higher rate of change in user
requirements and environment on which the software is working.
■ Large software - It is easier to build a wall than to a house or building, likewise, as the
size of software become large engineering has to step to give it a scientific process.
■ Scalability- If the software process were not based on scientific and engineering
concepts, it would be easier to re-create new software than to scale an existing one.
■ Cost- As hardware industry has shown its skills and huge manufacturing has lower down
he price of computer and electronic hardware. But the cost of software remains high if
proper process is not adapted.
■ Dynamic Nature- The always growing and adapting nature of software hugely depends
upon the environment in which user works. If the nature of software is always changing,
new enhancements need to be done in the existing one. This is where software
engineering plays a good role.
■ Quality Management- Better process of software development provides better and
quality software product.

3. CHARACTERISTICS
■ Software is developed
■ Software does not “Wear Out”
■ Software is highly malleable
■ Most software is created and not assembled
from existing components

4. SOFTWARE COMPONENTS
■ Off the self components
■ Full experience components
■ Partial experience components
■ New components

5. SOFTWARE
APPLICATIONS
■ Business software
■ System software
■ Embedded software
■ Scientific software
■ Personal computer software
■ Real time software
■ Web-based software

6. SOFTWARE CRISIS
■ Software is easy to change.
■ Software can work right the first time.
■ Reusing software increases the right code.
■ Computers provide great reliability than the devices
they replace.