The Unified Process lifecycle is an implementation of the spiral model. It has been created by assembling the content elements into semi-ordered sequences. Consequently the Unified Process lifecycle is available as a work breakdown structure, which will be customised to address the specific needs of a project. The Unified Process lifecycle organises the tasks into phases and iterations.
A project has four phases:
 Inception phaseThe Project Inception is the smallest phase in the project, and ideally it should be quite short. If the Inception Phase is long then it is usually an indication of excessive up-front specification, which is contrary to the spirit of the Unified Process. The following are the goals for the Inception phase. - Establish a justification or business case for the project which includes business context, success factors and financial forecast
- Establish the project scope, boundary conditions and project description (the core project requirements, constraints and key features)
- Outline the use cases and key requirements that will drive the design tradeoffs
- Outline one or more candidate architectures
- Outline the project plan
- Produce a system specification
- Produce a system interactive blueprint
- Identify risks
- Prepare a preliminary project schedule and cost quotation
After these are completed, the project is checked, via a champion / challenge process against the following criteria: - Stakeholder concurrence on scope definition and cost/schedule estimates.
- Requirements understanding as evidenced by the fidelity of the primary use cases.
- Credibility of the cost/schedule estimates, priorities, risks, and development process.
- Depth and breadth of any architectural prototype and interactive blueprint.
If the project does not pass this milestone, called the Lifecycle Objective Milestone, it can either be cancelled or it can repeat this phase after being redesigned to better meet the criteria.
The Lifecycle Objective Milestone marks the end of the Inception phase.
Elaboration phaseThe elaboration phase is where the project starts to take shape. In this phase the problem domain analysis is made and the architecture of the project gets its basic form. However, the primary goals of Elaboration are to address known risk factors and to establish and validate the system architecture. The architecture is validated primarily through the implementation of an Executable Architecture Baseline. This is a partial implementation of the system which includes the core, most architecturally significant, components. It is built in a series of small, time boxed iterations. By the end of the Elaboration phase the system architecture must have stabilised and the executable architecture baseline must demonstrate that the architecture will support the key system functionality and exhibit the right behaviour in terms of performance, scalability and cost. The final Elaboration phase deliverable is a plan (including cost and schedule estimates) for the Construction phase. At this point the plan should be accurate and credible, since it should be based on the Elaboration phase experience and since significant risk factors should have been addressed during the Elaboration phase. This phase must pass the Lifecycle Architecture Milestone by meeting the following criteria: - A use-case model in which the use-cases and the actors have been identified and most of the use-case descriptions are developed. The use-case model should be 80% complete.
- A description of the software architecture in a software system development process.
- An executable architecture that realises architecturally significant use cases.
- Business case and risk list which are revised.
- A development plan for the overall project.
- If the project cannot pass this milestone, there is still time for it to be cancelled or redesigned. After leaving this phase, the project transitions into a high-risk operations where changes are much more difficult and detrimental when made.
The Lifecycle Architecture Milestone marks the end of the Elaboration phase.
Construction is the largest phase in the project. In this phase the remainder of the system is built on the foundation laid in Elaboration. System features are implemented in a series of short, time boxed iterations. Each iteration results in an executable release of the software.
In this phase the main focus goes to the development of components and other features of the system being designed. This is the phase when the bulk of the coding takes place. In larger projects, several construction iterations may be developed in an effort to divide the use cases into manageable segments that produce demonstrable prototypes.
This phase produces the first external release of the software. Its conclusion is marked by the Initial Operational Capability Milestone.
The Initial Operational Capability Milestone marks the end of the Construction phase Transition phaseThe final project phase is Transition. In this phase the system is deployed to the target users. Feedback received from an initial release (or initial releases) may result in further refinements to be incorporated over the course of several Transition phase iterations. The Transition phase also includes system conversions and user training. In the transition phase, the product has moved from the development organisation to the end user. The activities of this phase include training of the end users and maintainers and beta testing of the system to validate it against the end users' expectations. The product is also checked against the quality level set in the Inception phase. If it does not meet this level, or the standards of the end users, the entire cycle in this phase begins again. If all objectives are met, the Product Release Milestone is reached and the development cycle ends. The Product Release Milestone marks the end of the Transition phase More Information:
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