The term software engineering is composed of two words, software and engineering. Software is more than just a program code. A program is an executable code, which serves some computational purpose. Software is considered to be a collection of executable programming code, associated libraries and documentations. Software, when made for a specific requirement is called software product.

Engineering on the other hand, is all about developing products, using well-defined, scientific principles and methods. So, we can define software engineering as an engineering branch associated with the development of software product using well-defined scientific principles, methods and procedures. The outcome of software engineering is an efficient and reliable software product.

IEEE defines software engineering as:

The application of a systematic, disciplined, quantifiable approach to the development, operation and maintenance of software.

Software engineers should

• adopt a systematic and organized approach to their work

• use appropriate tools and techniques depending on

  • the problem to be solved,

  • the development constraints and

• use the resources available

At the first conference on software engineering in 1968, Fritz Bauer defined software engineering as “The establishment and use of sound engineering principles in order to obtain economically developed software that is reliable and works efficiently on real machines”.

Stephen Schach defined the same as “A discipline whose aim is the production of quality software, software that is delivered on time, within budget, and that satisfies its requirements”.

Both the definitions are popular and acceptable to majority.

However, due to increase in cost of maintaining software, objective is now shifting to produce quality software that is maintainable, delivered on time, within budget, and also satisfies its requirements.