Methodologies: What and Why?
Software engineering is the practice of using selected process techniques to improve the quality of a software development effort. This is based on the assumption, subject to endless debate and supported by patient experience, that a methodical approach to software development results in fewer defects and, therefore, ultimately provides shorter delivery times and better value. The documented collection of policies, processes and procedures used by a development team or organization to practice software engineering is called its software development methodology (SDM) or system development life cycle (SDLC).
Methodology as Risk Management
The challenge in selecting and following a methodology is to do it wisely -- to provide sufficient process disciplines to deliver the quality required for business success, while avoiding steps that waste time, squander productivity, demoralize developers, and create useless administrivia. The best approach for applying a methodology is to consider it as a means to manage risk. You can identify risks by looking at past projects.
If your organization has been plagued by problems resulting from poor requirements management, then a robust requirements management methodology would be well advised. Once this problem has been solved, through a repeatable process, the organization might then streamline its process, while ensuring that quality is maintained.
Every step along the system development life cycle has its own risks and a number of available techniques to improve process discipline and resulting output quality. Moving through the development life cycle, you might encounter the following major steps:
- Project charter and business case
- Definition of the business process and business requirements
- Documentation of user, functional and system requirements
- Top level architecture, technical approach, and system design
- System decomposition into component and unit specifications and design
- Coding, unit test planning, and unit test
- Generation of test data for unit testing and system testing
- System integration and testing
- Implementation, delivery and cut-over
- Training and user support
- System upgrades and routine software maintenance
