The employer shall conduct" + "risk assessment

Phases:

Starting point: definition of all requirements, general, preliminary project | Choice of some Subset of system’s functions | Detail project and implementation of the System’s part realizing chosen functions. | Testing of the done part of the System and delivery to the client. | Repetition of the process.

-Planning (Objective setting) | Specific objectives for that phase of the Project are defined | Constraints on the Process and the product are identified|Detailed management plan Is drawn up|Project risks are Identified | Alternative strategies may be planned

-Risk Analysis (assessment and reduction) | For each of identified Risks a detailed analysis is carried out | Reduction of risk | Phase can Include prototype building

- Construction (development and validation) | Development model for The system is chosen. | Choice of The system development model.

-Testing (user’s evaluation): | The project is reviewed | Decision is made whether to continue With the further loop of the spiral.

•General Requirements definition•Prototype construction,•Prototype verification by the Client, •Full requirements definition, •Full requirements definition, •Full System’s realization according to waterfall model, •Requirements definition

•Preliminary Implementation // User’s check // Improvement in many versions until the final System is reached

Advantages

Frequent Contact with the user, not necessary to define all requirements on beginning, Early use by client of system, first increment fulfils most important Requirements, possible to use the system.

Disadvantages

Small Increments, every increment should deliver some functionality, addiotoional Cost of scheleton implementation, risk of no detection of some bugs during Testing phase.

Spiral

§ Advantages: •Explicit risk inclusion •Risk decrease •User evaluation/feedback § Disadvantages: •Useful for systems which can Be implemented with partial functionality and decreased quality •Long time of Reaching the final version

Throw awat Prototyping (this advatanges also useful for evolutionary):

Advantages: •Ability to demonstrate quickly working version of the system •Possibility of Trainings before system is ready §

Disadvantages: •Additional cost of prototype construction •Potential astonishment of the Client (time and cost of prototype creation cf full system)