difference between agile model and spiral model [duplicate]

Question

Can anyone explain me the differences between the spiral and agile models in simple terms as I am beginner?? Can you give me some real world egs. where spiral is more useful than agile and vice-versa... I know there are so many links available on internet but they are hard to understand as I am a beginner .. So it would be great help if you explain in simple terms?? Thanx in advance...

Answer 1

The Spiral Model is an example of iterative development. A typical iteration will be somewhere between 6 months and 2 years and will include all aspects of the lifecycle - requirements analysis, risk analysis, planning, design and architecture, and then a release of either a prototype (which is either evolved or thrown away, depending on the specific methods chosen by the project team) or working software. These steps are repeated until the project is either ended or finished.

Agile development, on the other hand, includes a number of different methodologies with specific guidance as to the steps to take to produce a software project, such as Extreme Programming, Scrum, and Crystal Clear. The commonality between all of the agile methods is that they are iterative and incremental. The iterations in the agile methods are typically shorter - 2 to 4 weeks in most cases, and each iteration ends with a working software product. However, unlike the spiral model, the software produced isn't a prototype - it is always high quality code that is expanded into the final product.