Software Development Lifecycle

• Course #3 is Cycle de vie

Cycle de vie

• Cycle de vie involves software development and evolution, realized as a process.

Process

• Process is a set of coordinated and regulated activities, the purpose of which is to create a product.

Development Process

• The development process involves a set of activities, their order, and how they are chained together, representing the stages of development.

Activities within a Process

• Activities within a process include inputs, outputs, the activity description, and the stakeholders and roles involved.
• Activity details consist of the name, description, and applicable guides and standards.

Current Activities

• Study the feasibility of the project
• Specify what the project needs to do
• Design
• Code
• Integrate
• Validate
• Maintain

Feasibility (Why)

• Feasibility involves problem-solving and achieving objectives
• It addresses questions like why develop, market presence, availability of better alternatives, and resource requirements (budget, personnel, and materials).
• The activity involves studying the project's feasibility, technical constraints (cost, time, quality), and potential alternatives.
• It leads to making a decision about whether to proceed with the project, assessing methods, tools, and techniques for producing software.
• It considers producing quality software within cost and time constraints.

Specification (What)

• Specification considers the client's ideas, system requirements, and needs.
• The activity involves describing what the software should do (black box behavior) and how to verify its functionality.
• The deliverable is the software's specifications document, expressed in text and diagrams.
• A precise definition of requirements leads to project success.
• Client needs can be imprecise and changing
• Solutions include freezing client needs early or tolerating imprecision and changes later.

Design (How)

• Activity involves using a specification to organize the software.
• It considers how to organize the software to fulfill its duties, technical choices, and ensuring correct organization.
• This results in a description of design decisions and test procedures.

Architectural Design

• Concerns decomposing the system, considering subsystems, interfaces, and component links.
• A description of the software architecture results.

Detailed Design

• Involves detailing the functioning of components, defining unit tests, and defining algorithms and data structures.
• A complete record of the detailed design and unit tests for each component results.

Quality of Software

• Software quality depends on whether the software is maintainable
• This involves maximizing internal consistency and minimizing coupling between components.

Coupling vs Coherence

• High cohesion and low coupling are desirable attributes in software design.
• Coupling indicates the degree to which one component is connected to other components
• Coherence or cohesion indicates the degree to which the elements inside that module belong together.

Implementation

• Implementation entry points are specification and design.
• The activity involves translating the design into code, writing it, and unit testing it.
• Code sources, unit tests, and documentation result.

Integration

• Integration entry points are design, source code, and integration tests.
• The activity involves assembling the code and performing integration tests to confirm if the software is organized as required.
• A report of integration tests results.

Validation

• Validation entry point is complete executable software to validate.
• The activity involves constructing the complete software and conducting integration tests to validate if the software fulfills expectations and quality standards.
• A report of validation tests results.

Maintenance

• Maintenance entry point is any stage of software development
• Involves corrective, adaptive, perfective, and preventive changes.
• The result is corrected software, updates, and revised documents.

Post-Deployment Activities

• During preventive maintenance, testing is done to address weaknesses and vulnerabilities found post-deployment.
• Corrective maintenance addresses errors, bugs, and imperfections.
• Adaptive maintenance ensures functionality across different software and hardware environments, adapting to current context requirements.
• Perfective maintenance aims to enhance functions, data structures, and interface design.