Software Process and Models Overview

Software Process

• Software process encompasses all activities involved in software engineering.
• A generic process model outlines a framework for software development. This includes umbrella activities and framework activities.
• Umbrella activities provide support throughout the entire software development life cycle (e.g., quality assurance, risk management).
• Framework activities define the core work tasks (e.g., communication, planning, modeling, construction, deployment).
• Each framework activity is further broken down into tasks sets with work tasks, work products, quality assurance points, and project milestones.

Process Flow Models

• Linear process flow: sequential phases without iterations.
• Iterative process flow: revisiting phases multiple times based on feedback and refinement.
• Evolutionary process flow: evolving the product iteratively from a basic prototype to a final product.
• Parallel process flow: concurrent execution of different phases, allowing some tasks to overlap.

Task Set Identification

• A task set outlines the actual work necessary to achieve specific software engineering actions.
• This involves a list of tasks, work products, and quality assurance processes.

Process Patterns

• A process pattern describes a recurring problem in software development.
• It identifies the environment where the pattern arises and suggests solutions to address the pattern.
• Specific patterns are discussed: stage, task, and phase.

Process Assessment and Improvement

• Standard CMMI Assessment Method (SCAMPI) is a five-step process for assessing software process maturity.
• CMM-based Appraisal for Internal Process Improvement (CBA/IPI) analyzes the maturity of an organization's software process, using the SEI CMM as a basis.
• SPICE (ISO/IEC15504) outlines the requirements for assessing software processes and provides guidelines to aid organizations.
• ISO 9001:2000 provides a generic quality standard applicable to software organizations.

Prescriptive Process Models

• Waterfall Model: sequential phases, inflexible to change.
• V-Model: illustrates verification and validation activities.
• Incremental Model: delivers working software incrementally.
• Evolutionary Model: focuses on prototyping and iterative refinement.

The Waterfall Model

• Follows a sequential life cycle, from communication, planning, modeling, construction, to deployment.

The V-Model

• A visual representation of the verification and validation activities throughout software development.

The Incremental Model

• Delivers working software in increments, adding functionality in each iteration.

The Evolutionary Model

• Uses prototyping and iterative development to progressively refine the product.

Prototyping

• Iterative refinement of a software product based on iterative feedback.

The Spiral Model

• Combining prototyping and controlled systematic aspects of waterfall model.

Concurrent Model

• Concurrent execution of different phases, allowing overlapping of tasks.

Specialized Process Models

• Component-based development involves reusing components instead of developing from scratch.
• Formal methods utilize mathematical specifications in software development.
• Aspect-oriented development focuses on integrating aspects to the software being developed.
• Unified Process (UP) is a "use case driven, architecture-centric" process closely aligned with UML.

Unified Process (UP)

• A software development process consisting of four phases: inception, elaboration, construction, and transition.

The Manifesto for Agile Software Development

• Values individuals and interactions over processes and tools.
• Working software over comprehensive documentation.
• Customer collaboration over contract negotiation.
• Responding to change over following a plan.

Agility

• Effective and rapid response to change.
• Effective communication among stakeholders.
• Bringing developers and customers together.
• Timely, incremental delivery of software.

Cost of Change with Agile vs. Conventional Processes

• Shows the cost of change decreases in agile processes when compared to conventional.

An Agile Process

• Driven by customer-defined requirements.
• Plans are short-lived, with iterative development.
• Focuses on construction activities.
• Delivers software increments.
• Adapts to changes.

Agile Principles

• Prioritizes customer satisfaction and continuous delivery.
• Welcomes changing requirements, even late in the process.
• Prioritizes frequent delivery of working software.
• Encourages customer collaboration and frequent communication.
• Focuses on individuals and interactions over processes and tools.
• Promotes self-organizing teams and supporting them.
• Embraces change for business advantage.
• Emphasizes continuous attention to quality and good design.
• Maximizing work not done is essential for simplicity.
• Builds best architecture, requirements and designs from self-organizing teams.
• Revisits behavior/process at periodic intervals to improve effectiveness, adapt, and tune.

Types of Agile Processes

• Extreme Programming (XP).
• Industrial XP (IXP).
• Scrum.
• Dynamic Systems Development Method (DSDM).

Extreme Programming (XP)

• Planning emphasizes "user stories."
• Stories are grouped into deliverable increments.
• A commitment is made on a date for increments. Project velocity is used to help define dates for subsequent deliveries.
• XP Design employs the KIS (Keep it Simple) principle, uses CRC (class-responsibility-collaborator) cards, and uses "spike solutions" (design prototyping) for tough design problems.
• XP Coding includes pre-coding unit tests and pair programming.
• XP Testing ensures all unit tests are executed daily and acceptance tests are defined by customers.

Industrial XP (IXP)

• Encompasses management and expanded customer roles/responsibilities.
• Includes practices like readiness assessment, project chartering, test-driven management, retrospectives, and continuous learning.

Scrum

• Work is partitioned into packets or sprints.
• Testing and documentation are ongoing alongside product construction.
• Work is derived from a backlog of existing requirements and evolves over sprints.
• Uses short, sometimes informal meetings (demos).

Dynamic Systems Development Method (DSDM)

• Encourages active user involvement, empowering teams to make decisions, and focuses on frequently delivering working products.
• Requires iterative and incremental development with focus on business use. All changes are reversible. Requirements are baselined at a high level.
• Testing is integrated throughout the life cycle.

Agile Modeling

• Originated by Scott Ambler.
• Utilizes multiple models, while emphasizing content over representation.

Agile Unified Process (AUP)

• Each iteration involves activities like Modeling, Implementation, Testing, Deployment, configuration and project management, and environment management.