Shortcomings of the Traditional Process Models

The traditional Systems Development Life Cycle (SDLC) used by many companies is activity- or task-driven. With variations across methodologies, the traditional life cycle typically consists of the distinct phases shown in the following list: Definition; Analysis; Design; Construction; Test; Transition and Migration; Production.

The term "phase" implies that each set of tasks must be completed before the next phase can begin. Typically, different teams handle each phase in the life cycle, and each phase must be heavily documented to allow for a different team to pick up the next phase. As a result, decisions freeze early and flexibility is minimized.

While this model provides a useful way to categorize the types of tasks that occur throughout the development life cycle, it does not recognize or leverage the characteristics of component-based enterprise development.

The major problem with the waterfall process model for component-based development is that it is task-focused rather than process-oriented. This makes it difficult to make the flexible decisions and meet the rapidly changing priorities that are vital to managing an enterprise development project with its multiple components and heavy emphasis on user interface requirements.

Overcoming these drawbacks requires a more flexible, iterative, process-oriented development model. The milestone-based process model is derived from the product life cycle model proven so successful within Microsoft Corporation. It encourages thinking about work in terms of processes rather than tasks. Milestones mark the self-regulation points of these processes.

The four characteristics of the milestone-driven model are:

• Milestone-based approach. The application development process is driven by external and internal milestones, which are checkpoints to guide the development process.

• Clear ownership and accountability. The process model connects responsibility for each milestone to the project team roles.

• Risk-driven scheduling. High risk components of a project are completed as early as possible.

• Versioned releases. The concept of versioned releases is an important one throughout the systems development life cycle because it impacts how expectations are set and how the entire project is planned and managed.