Software Development Essentials: Myths, Models, and Maintenance

Posted on Nov 21, 2024 in Other subjects

Debunking Software Myths

Hardware is not more important than software. Software development is not just programming; it’s a complex process. Errors in software are common but manageable.

Software Lifecycle Models

Waterfall Model

Each phase produces an output that serves as input for the next. Variants differ in how they define phases.

Stages:

  • Analysis: Define user needs and create the Software Requirement Document (SRD).
  • Design: Organize the system and create the Software Design Document (SDD).
  • Coding: Write and test source code with clear comments.
  • Integration: Combine components and conduct extensive testing.
  • Maintenance: Implement changes due to defects or improvements.

V-Model

A two-dimensional diagram representing development levels. Verification checks if a module meets specifications. Validation checks if the system meets user requirements.

Using Prototypes

Auxiliary elements to test solutions experimentally. Fast prototypes gain experience. Evolutionary prototyping refines the prototype iteratively.

Tools for Prototyping

  • 4th generation languages (declarative style).
  • Specification languages with prototype compilers.
  • Software reuse.

Spiral Model

Introduces risk analysis to guide development. Each cycle includes:

  • Planning: Define the development context.
  • Risk Analysis: Evaluate alternatives.
  • Engineering: Analysis, design, coding, integration, and maintenance.
  • Evaluation: Analyze results and plan the next cycle.

Models can be combined for a mixed lifecycle approach.

Software Maintenance

Repeating or redoing activities due to changes. Types:

  • Corrective: Fixing errors.
  • Adaptive: Adapting to new environments.
  • Perfective: Optimizing for performance.

Change management uses problem reports and change reports. Reengineering helps support older applications.

Software Quality Assurance

Ensuring product quality through reviews and testing.

Quality Factors:

  • Correction: Product performs as expected.
  • Reliability: Degree of non-failure.
  • Efficiency: Resource utilization.
  • Safety: Data access control.
  • Ease of Use: Learning effort.
  • Maintainability: Ease of fixing.
  • Flexibility: Ability to change.
  • Test Facility: Ease of testing.
  • Transportability: Adaptability to different platforms.
  • Reusability: Use in other developments.
  • Interoperability: Combination with other products.

Quality Assurance Plan (SQAP):

  • Team organization.
  • Lifecycle model.
  • Required documentation.
  • Reviews and audits.
  • Testing organization.
  • Maintenance organization.

Reviews: Inspect results for defects. Follow formal guidelines.

Tests: Run software under specific conditions to find errors.

Configuration Management:

  • Version control: Store successive versions.
  • Change control: Ensure compatibility.
  • Baseline: Specific system configuration.
  • Frozen baseline: Modified baseline that is not deleted.