Software Design

Software design is a process of problem-solving and planning for a software solution. After the purpose and specifications of software is determined, software developers will design or employ designers to develop a plan for a solution. It includes low-level component and algorithm implementation issues as well as the architectural view.

The Software Design Document (SDD) is a comprehensive software design model consisting of four distinct but interrelated activities: data design, architectural design, interface design, and procedural design.

1. Data Design describes structures that reside within the software. Attributes and relationships between data objects dictate the choice of data structures. 
2. Architecture Design uses information flow characteristics, and maps them into the program structure. Transformation mapping method is applied to exhibit distinct boundaries between incoming and outgoing data. The Data Flow diagrams allocate control input, processing, and output along three separate modules. 
3. Interface Design describes internal and external program interfaces as well as the design of human interface. Internal and external interface design are based on the information obtained from the analysis model. 
4. Procedural Design describes structured programming concepts using graphical, tabular, and textual notations. These design mediums enable the designer to represent procedural detail that facilitates translation to code. This blueprint for implementation forms the basis for all subsequent software engineering work.