Software Development Life Cycle Models

Typical models:

• Sequential: Waterfall
• Iterative and incremental: Agile/Scrum

Sequential

Linear process:

• Testing only begins once development has been completed.
• V-model integrates testing throughout, but it’s still waterfall.

Waterfall is basically when you’re testing once the software is implemented.

Iterative

Iterative process:

• Software is built incrementally in smaller cycles.
• Enables continuous feedback that informs future cycles.
• More flexible and adaptable than sequential.

Sequential vs Incremental

Whether waterfall or agile is better depends on the environment.

Stable software that rarely changes, where the requirements are well known and unlikely to change, is often better suited to waterfall.

Projects that are continuously changing in response to feedback are best suited to iterative models.