Spiral Model

SPIRAL MODEL

Ø  The Spiral Model is similar to the incremental model, with more emphasis placed on risk analysis.

Ø  In spiral Model, the angular component represents “PROGRESS” & the radial component represent “COST”.

Ø  Each cycle in the spiral begins with the identification of objectives for that cycle, the different alternatives that r possible for achieving the objectives & the constraint that exist.

Ø  Next Step in the cycle is to evaluate these different alternatives based on objectives & constraint, design for that cycle. The focus of evaluation in this step is based on the risk perception for the project. Risk reflects the chances that some of the objectives of the project may be not met.

Ø  The next step is to develop strategies that resolve uncertainties & risk. This step may involve activities such as benchmarking, simulation & prototyping.

Ø  Finally in 4^th quadrant we plan for the next cycle or module.

Ø  The spiral model works for development as well as enhancement projects.

ADVANTAGES

1)      High amt of risk analysis, so preferred for high risks projects.

2)      Good for large & mission critical projects.

3)      S/W is produced early in the s/w life cycle.

DISADVANTAGES

1)      Can be a costly model to use.

2)      Risk analysis requires specific expertise...

3)      Project’s success is highly dependent.