Software Processes

• Software process


  A set of related activities that leads to the production of the software
• Four activities in any software process

  • Software specifications
  • Software development
  • Software validation
  • Software evolution
• Supporting activities in software process

  • Configuration and change management
  • Quality assurance
  • Project management
  • User experience
• Change Management


  Managing changes related to project management plans, processes, and baselines
• Configuration Management


  Managing changes related to product scope
• Software quality assurance (SQA)


  A process which assures that all software engineering processes, methods, activities and work items are monitored and comply against the defined standards
• Project Management


  The application of knowledge, skills, tools, and techniques to project activities to meet the project requirements
• User Experience (UX) design

  The process design teams use to create products that provide meaningful and relevant experiences to users
• Software process is complex, it relies on making decisions
• There's no ideal process and most organizations have developed their own software process
• Software process model


  A simplified representation of a software process
• Software process models


  • Each model represents a process from a specific perspective
  • They can be adapted and extended to create more specific processes
• Waterfall Model


  A sequential approach, where each fundamental activity of a process represented as a separate phase, arranged in linear order

  
• Plan-driven process


  A process where all the activities are planned first, and the progress is measured against the plan
• Phases of Waterfall model

  1. Requirements gathering and analysis

  2. System Design

  3. Implementation

  4. Integration and Testing

  5. Deployment of system

  6. Maintenance

  
• In practice, the phases of Waterfall model overlap and feed information to each other

  
• Prototyping


  A version of a system or part of the system that's developed quickly to check the customer's requirements or feasibility of some design decisions
• Phases of Prototyping


  1. Establish objectives

  2. Define prototype functionality

  3. Develop the prototype

  4. Evaluate the prototype
• Incremental Development


  Developing an initial implementation, exposing this to user feedback, and evolving it through several versions until an acceptable system has been developed
• Each system increment reflects a piece of the functionality that is needed by the customer
• Spiral Model


  A risk-driven model where the process is represented as spiral rather than a sequence of activities
• Phases of Spiral Model

  1. Objective setting

  2. Risk assessment and reduction

  3. Development and validation

  4. Planning
• Iterative Development


  Aims to develop a system through building small portions of all the features, across all components
• Phases of Iterative Development

  1. Inception

  2. Elaboration

  3. Construction

  4. Transition
• Agile


  A group of software development models based on the incremental and iterative approach
• Agile methods minimize documentation by using informal communications rather than formal meetings with written documents
• Increment


  Builds a complete feature of the software
• Iterative


  Builds small portions of all the features
• Agile


  Combines the incremental and iterative approach by building a small portion of each feature, one by one, and then both gradually adding features and increasing their completeness
• Software crisis


  The difficulty of writing useful and efficient computer programs in the required time
• Aspects of software crisis

  • Size
  • Quality
  • Cost
  • Delayed Delivery
• Software testing typically finds 25 errors per 1000 lines of code
• Development of the FAA's Advanced Automation System cost over $700 per lines of code
• One in four large-scale development projects is never completed