Lecture 2

Software Process

Software Process

• Life cycle: the process involves the building of a product.
• For a software, its life cycle terminates when the provider stops support.

Software Process Model (Development Patter)

Waterfall Model

• A stepwise refinement of requirement.

• Suitable when the requirement is well-determined and understood.

• Drawback:

  • inflexible partitioning of project
  • difficult to update
  • It describes a process of stepwise refinement of the requirement

Evolutionary Development

• Develop software form a initial implementation, then refine (add new features) it based on user's response.

• Evolutionary development involves Exploratory development. (Exploratory \(\in\) Evolutionary)

  • Exploratory development starts with a well-understood requirement
  • The system evolves by adding new features

• Drawbacks:

  • Lack of process visibility
  • Sometimes poorly structured
  • Not suitable in safety critical projects

Agile and Scrum

• Lightweight approach to software development
• Test driven development
• Pair programming
• Scrum: Incremental Development
  • Development and delivery is broken down into increments (sprints) that gives part of the functionality
  • High priority requirement are included in early increments
  • once the development of an increment is started, the requirements are frozen through requirements, so that later increment can continue to evolve.

Advantage

• Customers' value can be delivered with each increment, so system functionality is avaiable earlier.
• early increments act as a prototype to help elicit requirements for later increment.
• lower risk of overall project failure
• the highest priority functions tend to receive more testing.

Summary

• iterative process models describe the software process as a cycle of activities
• generic process models describe the organisation of software processes
• general activities are: specific specification design and implementation, validation and evolution
• software process at the activities involved in producing and evolving a software system there were represented in a software process model