SDLC (Linear and Evolutionary)
Difference between Linear and Evolutionary
*Linear:* Step-by-step approach (Waterfall). Each step must be completed, understood and agreed before the next step can be started. *Evolutionary:* The system evolves through early prototyping and progressive versions of the system (Iterative).
What does SDLC contain of:
*Two approaches:-* Evolutionary Linear *Five basic life cycles:-* Waterfall Incremental "V" model Iterative Spiral
The stages of a SDLC *FRDDTI*
1. Feasibility study 2. Requirements engineering 3. Design 4. Development 5. Testing 6. Implementation
The linear life cycles include: WIV
1. Waterfall 2. Incremental 3. "V" model
The five SDLC's are? WIVIS
1. Waterfall 2. Incremental 3. "V" model 4. Iterative 5. Spiral
The evolutionary life cycles: IS
4. Iterative 5. Spiral
Iterative development
A minimum of 3 iterations would typically be required to achieve an external release.
What is a Systems development lifecycle? *PBT&D*
A systems development life cycle is a *"Framework"* Describes the stages we follow to plan, design, build, test and deliver information systems.
3rd Iteration:
Consolidate
1st Iteration:
Investigate
What is Iterative?
It is a life cycle where the overall project is composed of several small time- boxed developments, called iterations which take place in sequence. They can look a bit like mini-linear projects.
2nd Iteration:
Refine
What is the "V" model?
The "V" model is an extension to the waterfall model to deal with problems that occurred during a waterfall life cycle. The problems include running out of time and money.
What is an incremental model?
The incremental model is implemented and incremented (a little more is added each time) until the product is finished.
What is spiral?
The spiral life cycle does not need requirements to be defined in advance. The project has 4 phases called spirals, which are concepts that need to be repeatedly revisited until a working product is complete.
What is the waterfall model?
The waterfall model illustrates the software development process in a linear sequential flow.
What is scope creep?
Uncontrolled changes in a project scope. Can occur if the scope of a project is not properly defined, documented or controlled. It is considered harmful.