What is software engineering?

Before we dive deeper into this chapter, we need to establish an understanding of some of the basic terms and concepts around software engineering. For starters, how do we define software engineering and in what ways does it differ from software development and programming in general? To begin answering this question, we will start by examining the formal definition of software engineering, as published in IEEE's Standard Glossary of Software Engineering Terminology ^[7]:

"Software engineering is defined as the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software."

The main takeaway from this definition is that authoring code is just one of the many facets of software engineering. At the end of the day, any capable programmer can take a well-defined specification and convert it into a fully functioning program without thinking twice about the need to produce clean and maintainable code. A disciplined software engineer, on the other hand, would follow a more systematic approach by applying common design patterns to ensure that the produced piece software is extensible, easier to test, and well documented in case another engineer or engineering team assumes ownership of it in the future.

Besides the obvious requirement for authoring high-quality code, the software engineer is also responsible for thinking about other aspects of the systems that will be built. Some questions that the software engineer must be able to answer include the following:

• What are the business use cases that the software needs to support?
• What components comprise the system and how do they interact with each other?
• Which technologies will be used to implement the various system components?
• How will the software be tested to ensure that its behavior matches the customer's expectations?
• How does load affect the system's performance and what is the plan for scaling the system?

To be able to answer these questions, the software engineer needs a special set of skills that, as you are probably aware, go beyond programming. These extra responsibilities and required skills are the main factors that differentiate a software engineer from a software developer.