System Development Life Cycle

The system development life cycle(SDLC) is a methodology for developing information systems.
It has five phases

1. Analysis
2. Design
3. Development
4. Implementation
5. Maintenance and Review

• Formal review at the end of each phase allows maximum management controls.
• This approach creates considerable system documentation,
• Formal documentation ensures that system requirements can be traced back to stated business needs.
• It produces many intermediate products that can reviewed to see whether they meet users' needs and confirm to standard.
• Users get a system that meets the needs understood by the developers, this may not be what was really needed.
• Documentation is expensive and time consuming to create. It is also difficult to keep current.
• Often users needs go unstated or are misunderstood.
• Users cannot easily review intermediate products and evaluate whether a particular product (i.e data flow diagram) meets their business needs.
• System development life cycle is not the only form of systems development.
• Two main types of systems development are prototyping and rapid application development.
• Prototyping is an iterative approach to the system development process.
• During each iteration, requirements and alternative solutions to the problems are identified and analyzed, new solutions are designed.
• An example is prototyping a new car. Many prototypes are designed until the final car design is developed.
• There are two main types of prototyping
1. Operational prototyping: a functioning prototype that access real data files, edits input and makes necessary computations and comparisons.
2. Non operational prototyping: a mock up or model that include output and input specifications and formats.