Design

This step is during which the design of the software is done. The software develpoment process gets technical in here.There are three main thign sdoen during this step.

1. Design Considerations: There are different design considerations like,

• Extensibility
• Fault-tolerance
  
• Maintainability
  
• Reliability
  
• Reusability etc.

All these should be taken into considerations.

2. Modelling Language: There are different types of modelling language which can be used to represent the knowledge about the system as a set of rules. There are both graphical and textual types of languages avalable in the industry.One famous such language is UML ( Unified Modelling Language)

3. Design Pattern: Most softwares developed might have been already developed for some similar problems. Many times it is easy to have that already proven software pattern to solve our problem. In the design phase the software team identifies the pattern that has to be followed for that particular project. Some examples are Factory pattern, proxy pattern etc.