Software Development and Quality Attributes

Software Engineering Definition

• Software Engineering is the systematic application of engineering principles, methodologies, and practices to the design, development, testing, deployment, and maintenance of software systems.
• It uses structured processes, tools, and techniques to create software that meets user requirements, is reliable, scalable, maintainable, and delivered on time and within budget.

Key Aspects of Software Engineering

• Systematic Approach: Software engineering employs a structured, well-defined approach to the entire software development lifecycle to ensure quality and efficiency.
• Engineering Principles: Utilizes engineering principles such as systematic analysis, design, testing, evaluation, and implementation to develop software.
• Processes and Methods: Involves defined processes (requirement analysis, design, coding, testing, maintenance), along with models and methods for managing these processes.
• User Requirements Focus: Prioritizes understanding and satisfying user needs by creating functional, usable, and efficient software solutions.
• Quality, Cost, and Schedule Management: Aims to balance quality with constraints like development time (schedule) and financial costs.

Objectives of Software Engineering

• Quality Software Development: Creating reliable, efficient, maintainable, and error-free software.
• Timely Delivery: Completing projects on time while adhering to the agreed-upon schedule.
• Cost Management: Ensuring the project is completed within budget.
• User Satisfaction: Producing software that aligns with user expectations.
• Maintenance and Flexibility: Designing software that can adapt to future changes with minimal cost and effort.
• Risk Management: Identifying, analyzing, and addressing potential problems early.

Software Engineering vs Programming

• Programming focuses on writing and debugging code.
• Software engineering is broader, encompassing requirements gathering and analysis, design of software architecture, application of software development models and methodologies, rigorous testing to find and fix bugs, and management of the deployment and maintenance lifecycle.

Importance of Software Engineering

• Complexity Management: Provides systematic methods to manage the complexity of software systems.
• Quality Assurance: Employing systematic testing, validation, and development practices ensures the delivery of high-quality systems.
• Timely Delivery and Budget Constraints: Structured approaches to ensure projects are delivered on time and within budget.
• User-Centered Development: Emphasizes meeting user requirements and incorporating feedback throughout the development process.
• Adapting to Change: Incorporates flexibility to adjust to technological changes.

Cost, Schedule, and Quality in Software Engineering

• These three elements are interconnected (often referred to as the "triple constraint" or "iron triangle").
• Changes to one factor (e.g., cost) can impact the others (e.g., schedule and quality).
• Cost refers to the total financial resources required to develop and deliver the software product (labor, tools, licenses, hardware, training, testing, and maintenance).

Factors Influencing Software Cost

• Personnel costs (salaries).
• Tool and technology costs.
• Training costs.
• Project complexity.
• Team experience.

Factors Influencing Schedule

• Project size and complexity.
• Team size.
• Development model (e.g., Waterfall, Agile).
• Tools and technology.
• Resource availability.

Factors Influencing Quality

• Requirements changes.
• Effective time management (project planning, task prioritization, risk management, monitoring & tracking).
• Using Agile or iterative models for flexibility and adaptability.

Definition of Quality Attributes

• Correctness: Extent to which software meets user requirements and performs intended functions.
• Reliability: Capacity to function correctly over time.
• Usability: Ease of use for end-users.
• Maintainability: Ease of fixing bugs, upgrading, and adapting the software.
• Portability: Ease of adaptation to new environments or platforms.
• Scalability: Ability to efficiently handle increasing workloads or numbers of users.
• Robustness: Capacity to handle unexpected or erroneous inputs.

Ensuring Quality

• Requirements analysis.
• Design and architecture.
• Testing.
• Code reviews and inspections.
• Standards and best practices (coding standards, design principles).
• User feedback and validation.

Summary of Common Quality Attributes

• Each attribute is briefly defined and accompanied by example of how the attribute is achieved.

Software Development Process Models

• Methods to organize and manage the SDLC (e.g., Waterfall, Prototyping, Iterative, Spiral, Agile). Each model has unique phases, advantages and disadvantages; uses cases to know which model is suitable for a project.
• The various models and their key characteristics, strengths, and weaknesses.

COCOMO Model

• A software cost estimation model.
• Helps project managers predict effort, cost, and time for software development projects using mathematical formulas based on project attributes and the project's size.
• Key concepts of the COCOMO model are discussed.
• The different COCOMO model variants are discussed (Basic, Intermediate, and Detailed). Each includes the different cost drivers.
• Mathematical representation used by the model.

Errors, Faults, and Failures in Software Engineering

• Distinguishes "error," "fault," and "failure."
• Human error, design errors, coding errors, testing errors, requirement errors, configuration errors, integration, and environment issues are examples of possible root causes of errors.
• Also details the types of software errors, including possible implications of their effects on the development projects, and describes how they are handled.
• Includes strategies for the prevention of errors, faults, and failures.

Top-Down vs Bottom-Up Approach

• Explaining top-down and bottom-up approaches in software design and development, the advantages and disadvantages of both, and when to use each approach.
• Top-down (starts with the overall system and breaks it down into smaller modules), bottom-up (starts with individual modules and combines them into larger subsystems).

Black Box Testing

• Overview of testing techniques focused on the functionality of software without examining its internal structure (e.g., equivalence partitioning, boundary value analysis, decision tables, state transition testing, error guessing).
• Methods, rationale and advantages and disadvantages of black-box testing.
• Typical examples of black box testing are also given

White Box Testing

• Overview of testing techniques focused on the internal structure of software (e.g., coding/logic testing, static analysis, control flow, data flow).
• Methods, rationale, and advantages and disadvantages of white-box testing.
• Typical examples are given.

Alpha Testing

• A type of testing done by internal testers.
• Focused on functionality and usability, and performed in a controlled environment.
• Used to identify issues in the early stages of the development cycle, before external users.
• Key characteristics, objectives, and process and personnel involved.

Beta Testing

• Testing done by external users, often for a period of time.
• Conducted after Alpha Testing
• Provides real-world usage feedback.
• Key characteristics, objectives, and process
• Types of beta testing (closed and open).

Validation vs Verification

• Definitions and key differences of validation and verification.
• Their roles within the SDLC and rationale for both are clarified.
• Typical use cases are given.

This quiz explores critical trade-offs in software development and the impact of resource allocation on project schedules. It delves into software quality attributes, including correctness, reliability, and robustness, and discusses various testing methods to ensure high quality. Additionally, the quiz examines design approaches and the significance of system testing in the software testing life cycle.