What is a software development model?

Answer 1

There is nothing like a "best" software development model. However, let us how it has evolved. Conventionally, everybody was using the waterfall model, where you start with requirements gathering, then analysis and design, architecture, coding, testing and maintenance. All these were done sequentially. But then, the characteristics of software is different from something like a "building construction". There are different set of problems: 1. Requirements may not be clear. 2. Users may not be able to tell or the developers may not be able to understand, the "real requirements" 3. A particular design may not suite the chosen architecture 4. Users will "ask for more" when they see the software. 5. It is important we "attack" the most risky items first. 6. Testing cannot be an activity at the end. All these prompted a spiral model, or what is referred to as "iterative" and "incremental". In fact Unified Modeling Language (UML) which is being commonly used now is closely related to iterative and incremental process. For most of the modern software development efforts iterative and incremental process suits well.

Answer 2

Software engineering is done various phases, these phases are like requirement gathering , designing etc. For software engineering there are various models, these are known as software development models.