Software Engineering Question Bank Solution 2080

In the software development process, how does software configuration management facilitate the changes that may occur during different stages of a software development life cycle? Justify your explanation with example.

Software Configuration Management (SCM) is the process of tracking and controlling changes to software and related documentation throughout the software development life cycle (SDLC). SCM facilitates the management of changes by providing mechanisms for version control, configuration identification, change control, and configuration auditing.

1. Version Control

SCM enables developers to keep track of different versions of software artifacts such as source code, documents, and configurations. Version control systems (VCS) allow developers to manage changes, revert to previous versions if needed, and collaborate effectively. For example, if a developer needs to modify a source code file during the development phase, SCM ensures that previous versions are preserved, and changes are tracked. This prevents the loss of valuable code and allows for easy rollback if the modifications introduce errors.

2. Configuration Identification

SCM helps in identifying and managing different configurations of software products. It defines baselines for each configuration, including the set of components, their versions, and dependencies. For instance, during the testing phase, SCM ensures that the test environment is properly configured with the correct version of the software under test, along with any necessary test data and dependencies. If changes are made to the configuration, SCM ensures that the changes are documented and tracked.

3. Change Control

SCM provides mechanisms for controlling and managing changes to software artifacts. Change control processes ensure that proposed changes are evaluated, approved, and implemented in a controlled manner. For example, if a new feature request is received during the maintenance phase, SCM ensures that the request goes through a formal change control process. This may involve assessing the impact of the change, obtaining approvals from stakeholders, and updating documentation accordingly.

4. Configuration Auditing

SCM facilitates auditing of software configurations to ensure compliance with standards, policies, and regulations. Auditing helps in verifying the integrity and consistency of software artifacts across different stages of the SDLC. For instance, during the deployment phase, SCM conducts configuration audits to ensure that the deployed software matches the intended configuration specified in the release documentation. Any discrepancies or unauthorized changes are identified and addressed through corrective actions.

Explain the main activities used in requirements engineering. What are the desirable characteristics of a good SRS documents? Explain with example.

The main activities used in requirements engineering:

Elicitation

Elicitation involves gathering requirements from stakeholders, including end-users, customers, domain experts, and other relevant parties. The goal is to understand their needs, expectations, and constraints regarding the software system. Various techniques such as interviews, surveys, workshops, brainstorming sessions, observations, and document analysis are commonly used to elicit requirements. Eliciting requirements can be challenging due to incomplete or inconsistent stakeholder input, changing requirements, and communication barriers.

Analysis:

Requirement analysis focuses on understanding, refining, and organizing the gathered requirements to ensure they are complete, consistent, feasible, and relevant to the project goals. It involves identifying stakeholders’ needs, priorities, and conflicts and defining the scope of the system. Techniques such as requirements prioritization, requirement structuring (e.g., use case modeling, data modeling), and requirements validation (e.g., reviews, prototyping) are used during analysis. Analyzing requirements requires balancing conflicting priorities, managing changing requirements, and ensuring alignment with the overall project objectives.

Specification:

Requirement specification involves documenting the elicited and analyzed requirements in a structured format to ensure clarity, completeness, and unambiguity. The specifications serve as a baseline for the development team and other stakeholders. Specifications may include textual descriptions, diagrams (e.g., use cases, activity diagrams, class diagrams), prototypes, formal models, or a combination of these depending on the project’s needs. Specifying requirements requires translating stakeholder needs into precise and understandable terms, avoiding ambiguity, and ensuring that all relevant aspects of the system are adequately described.

Validation:

Requirement validation ensures that the specified requirements accurately represent stakeholders’ needs and can be implemented to achieve the desired objectives. It involves verifying the correctness, consistency, completeness, and verifiability of the requirements. Validation techniques include reviews (e.g., walkthroughs, inspections), prototyping, simulation, and validation testing. Validating requirements requires addressing conflicts and inconsistencies, managing stakeholder expectations, and ensuring that the requirements align with the system’s goals and constraints.

Management:

Requirement management involves tracking changes to requirements, ensuring traceability between requirements and other project artifacts, and maintaining consistency throughout the development process. It also includes communication and collaboration among stakeholders to address evolving requirements. Requirement management tools, version control systems, and collaboration platforms are used to manage requirements effectively. Managing requirements involves handling changes, controlling scope creep, resolving conflicts, and ensuring that requirements remain aligned with the project’s goals and constraints.

 

The Software Requirements Specification (SRS) document serves as a comprehensive guide that outlines the functional and non-functional requirements of the software system to be developed. Some desirable characteristics of a good SRS document:

1. Clear and Unambiguous: The SRS should be written in clear and concise language without ambiguity. It should be easily understandable by all stakeholders, including developers, testers, and clients.
2. Complete: The document should capture all relevant requirements, including functional requirements (what the system should do) and non-functional requirements (quality attributes such as performance, usability, security, etc.).
3. Consistent: The requirements specified in the SRS should be consistent with each other and should not contradict one another.
4. Correct: The requirements should accurately reflect the needs and expectations of the stakeholders.
5. Verifiable: Each requirement should be verifiable, meaning it should be possible to determine whether the system meets that requirement once it is implemented.
6. Traceable: The SRS should provide traceability between the requirements and their sources (e.g., stakeholder requests, business processes) and between requirements and other system artifacts (e.g., design documents, test cases).

Example: Let’s consider an example of an SRS document for an online shopping website:

• Functional Requirement:
  • FR1: The system shall allow users to browse products by category.
  • FR2: The system shall allow users to add products to their shopping cart.
• Non-functional Requirement:
  • NFR1: The system shall respond to user actions within 2 seconds under normal load conditions.
• Traceability:
  • TR1: FR1 is derived from stakeholder interviews conducted with potential users.
  • TR2: FR2 is derived from the business requirement to facilitate easy shopping experience for users.

Explain architectural views. Illustrate on layered architecture, repository architecture, and pipe and filter architecture.

Architectural views provide different perspectives or abstractions of a software system’s architecture, each focusing on specific aspects of the system. These views help stakeholders understand different aspects of the system’s design and aid in communication between various stakeholders involved in the software development process.

Layered Architecture

Layered architecture organizes the system into horizontal layers where each layer represents a different level of abstraction or functionality. Each layer provides services to the layer above it and consumes services from the layer below it.

Illustration:

• Presentation Layer: Handles user interaction and interfaces.
• Application Layer: Implements business logic and workflows.
• Data Access Layer: Manages data access and storage.

Benefits:

• Separation of concerns: Each layer focuses on specific responsibilities.
• Modifiability: Changes in one layer do not necessarily affect other layers.
• Reusability: Layers can be reused in different parts of the system.

Repository Architecture

Repository architecture centralizes data management by using a repository or a centralized store for data. It separates the business logic from data access and manipulation operations.

Illustration:

• Repository: Acts as a central store for data storage and retrieval.
• Business Logic: Implements application-specific logic.
• Data Access Objects (DAOs): Handles database operations and interacts with the repository.

Benefits:

• Centralized data management: Simplifies data access and ensures consistency.
• Encapsulation: Business logic is decoupled from data access operations.
• Flexibility: Allows for easier integration with different data sources.

Pipe and Filter Architecture

Pipe and filter architecture decomposes the system into a series of components (filters) connected by communication channels (pipes). Each filter performs a specific transformation or processing task on data passing through it.

Illustration:

• Filters: Individual components responsible for processing data.
• Pipes: Channels through which data flows between filters.
• Source Filter: Produces initial data.
• Sink Filter: Consumes processed data.

Benefits:

• Modularity: Filters are independent and can be easily added, removed, or modified.
• Reusability: Filters can be reused in different configurations.
• Scalability: Supports parallel processing and distributed architectures.

Explain software engineering ethics with example.

Software engineering ethics refers to the principles and standards that guide the behavior and decision-making of software engineers in their professional practice. These ethics encompass responsibilities towards clients, users, colleagues, employers, and society as a whole.

Professional Responsibility:

Software engineers have a responsibility to ensure that their work meets high standards of professionalism and integrity. They should strive to deliver quality software that meets the needs of clients and users while adhering to legal and ethical guidelines.

Example: A software engineer discovers a critical security vulnerability in a widely used software application developed by their company. Despite pressure from management to release the software on schedule, the engineer insists on delaying the release to address the security flaw properly. This action demonstrates the engineer’s commitment to professional responsibility and prioritizing the safety and security of users over meeting deadlines.

Honesty and Integrity:

Software engineers should be honest and truthful in their interactions with clients, colleagues, and other stakeholders. They should not engage in deceptive practices or misrepresentations that could undermine trust or compromise the integrity of their work.

Example: During a client meeting, a software engineer accurately communicates the limitations and risks associated with a proposed software solution, even though doing so may lead to potential project delays or additional costs. By being transparent about the project’s challenges, the engineer upholds honesty and integrity, fostering trust with the client and promoting realistic expectations.

Respect for Privacy and Confidentiality:

Software engineers should respect the privacy and confidentiality of sensitive information obtained during the course of their work. They should safeguard personal data and proprietary information against unauthorized access, disclosure, or misuse.

Example: A software engineer working for a healthcare company is entrusted with access to patients’ medical records as part of developing a new electronic health records system. The engineer ensures that appropriate security measures are in place to protect patient confidentiality and adheres to strict privacy policies to prevent unauthorized access or disclosure of sensitive health information.

Social Responsibility:

Software engineers have a responsibility to consider the broader societal impacts of their work and to use their skills for the public good. They should strive to create software that promotes fairness, diversity, accessibility, and sustainability while minimizing negative consequences such as environmental harm or societal inequities.

Example: A team of software engineers develops a mobile app aimed at helping people reduce their carbon footprint by providing information and tools for adopting environmentally friendly habits. The app includes features such as carbon footprint tracking, eco-friendly product recommendations, and community forums for sharing sustainability tips. By addressing environmental concerns and promoting sustainable behavior, the engineers demonstrate social responsibility in their work.

Differentiate between evolutionary and throw-away prototyping model.

Evolutionary model	Throw-away model
The main purpose of evolutionary prototyping is to develop a robust, incremental version of the final product. It involves building a basic system that can evolve through successive iterations, with each iteration adding new features and improvements based on user feedback and changing requirements.	The primary purpose of throw-away prototyping is to quickly explore and validate concepts, designs, or specific functionalities. The prototype is not intended to be part of the final product and is discarded after it serves its purpose of gathering feedback and insights.
The prototype developed in an evolutionary prototyping approach is intended to evolve gradually into the final product. It serves as a foundation upon which subsequent iterations are built, and its lifespan extends throughout the development process.	The prototype developed in a throw-away prototyping approach is disposable and has a short lifespan. Once its purpose of validating concepts or gathering feedback is fulfilled, it is discarded, and its code is not reused in the final product.
Evolutionary prototypes typically cover a broader scope of the final product’s functionality. They aim to address a significant portion of the requirements and may include core features and functionalities that are expected to evolve over time.	Throw-away prototypes usually focus on specific aspects or functionalities of the final product. They are often limited in scope and may only address particular user interactions, interfaces, or design elements.
The feedback loop in evolutionary prototyping is continuous and iterative. Users and stakeholders provide feedback on each iteration, which is then used to refine and improve subsequent versions of the prototype.	The feedback loop in throw-away prototyping is typically shorter and more focused. The prototype is quickly developed, tested, and evaluated to gather immediate feedback and insights, after which it is discarded.
Evolutionary prototyping helps mitigate risks associated with changing requirements and uncertainties by allowing for early validation and adaptation. It enables stakeholders to explore various solutions iteratively, reducing the likelihood of costly changes later in the development process.	Throw-away prototyping helps mitigate risks associated with unclear or ambiguous requirements by providing a platform for rapid experimentation and validation. It allows stakeholders to quickly explore different design alternatives and identify potential issues early in the development cycle.

Differentiate plan driven and agile development.

Plan-driven	Agile
In plan-driven development, detailed plans and schedules are created upfront, outlining the entire development process from requirements gathering to deployment. These plans are based on comprehensive documentation and predictive forecasting, with emphasis on following a predefined sequence of activities.	Agile development emphasizes flexibility and adaptability over detailed upfront planning. Rather than creating exhaustive plans at the beginning of the project, Agile teams prioritize iterative development and continuous planning. Planning is done incrementally, with a focus on responding to change and adjusting priorities based on feedback from stakeholders.
Plan-driven approaches tend to be less flexible in accommodating changes to requirements, scope, or priorities once the project has started. Changes often require extensive rework and may impact the project’s timeline and budget.	Agile methodologies prioritize flexibility and responsiveness to change. Agile teams embrace changes in requirements and priorities, accommodating them through iterative development cycles and frequent feedback loops. This flexibility allows Agile projects to adapt to evolving needs and deliver incremental value to stakeholders.
Plan-driven approaches rely heavily on comprehensive documentation, including detailed requirements specifications, design documents, and project plans. Documentation serves as a contract between stakeholders and provides a basis for managing expectations and tracking progress.	Agile methodologies prioritize working software over comprehensive documentation. While Agile projects still produce documentation, the emphasis is on delivering value through working software and frequent collaboration with stakeholders. Documentation is kept to a minimum and is typically focused on capturing essential information needed for development and decision-
Plan-driven approaches often involve a more hierarchical structure with clearly defined roles and responsibilities. Team members may work in silos, with limited collaboration between different functional areas (e.g., development, testing, requirements analysis).	Agile methodologies promote cross-functional teams that collaborate closely throughout the development process. Team members from different disciplines work together in a collaborative environment, sharing knowledge, skills, and responsibilities. Collaboration is emphasized through practices such as daily stand-up meetings, frequent reviews, and continuous communication.
Feedback loops in plan-driven approaches tend to be less frequent and may occur at predefined milestones or checkpoints. Changes based on feedback are typically managed through formal change control processes and may involve significant overhead.	Agile methodologies prioritize continuous feedback and iteration. Agile teams engage stakeholders early and often, seeking feedback on working software through regular demonstrations and reviews. Changes based on feedback are integrated into the development process quickly, allowing for rapid adaptation and improvement.

What is the difference between functional and non-functional requirement? Which is more critical and why?

Functional	Non-functional
What the product does	How the product works
Focus on user requirements	Focus on user expectations
Product features	Product properties
Defined by user	Defined by developers
Mandatory	Not mandatory, but desirable

Functional requirements are often considered more critical than non-functional requirements. Here’s why:

1. Direct User Interaction: Functional requirements directly dictate the features and functionalities that users interact with, shaping their experience with the software. Meeting functional requirements ensures that the software meets the core needs and expectations of its users.
2. Primary Purpose: The primary purpose of software is to provide specific functions and capabilities to users. Functional requirements define what the software should do and form the basis for its development. Without meeting functional requirements, the software would not fulfill its intended purpose.
3. Client Satisfaction: Clients and stakeholders typically prioritize functional requirements as they directly address their needs and objectives for the software. Meeting these requirements ensures client satisfaction and increases the likelihood of project success.
4. Measurable Deliverables: Functional requirements are often more tangible and easier to measure compared to non-functional requirements. They provide clear criteria for evaluating the completeness and success of the software system.
5. Foundation for Further Development: Functional requirements serve as the foundation for further development and refinement of the software. Once the core functionalities are in place, non-functional aspects such as performance, security, and usability can be addressed to enhance the overall quality of the software.

What is release testing? Differentiate between release testing and system testing.

Release testing, also known as acceptance testing or deployment testing, is conducted to ensure that a specific version or release of the software is ready for deployment to users or customers. The primary goal of release testing is to validate that the software meets the required quality standards and is fit for production use.

Release Testing	System Testing
The purpose of release testing is to validate that a specific version or release of the software is ready for deployment to users or customers.	The purpose of system testing is to evaluate the behavior of the entire software system as a whole, typically before it is released for production use.
Release testing occurs after system testing and focuses on validating the software for deployment.	System testing occurs before release testing and focuses on evaluating the system’s behavior and quality in a controlled test environment.
Release testing verifies the overall functionality, reliability, and performance of the software as a whole in a production-like environment.	System testing evaluates the integrated components of the system and tests its functionality, performance, security, and other non-functional aspects in a controlled test environment.
Release testing involves stakeholders such as product owners, end-users, and customer representatives who assess whether the software meets their expectations and requirements.	System testing primarily involves members of the development team, QA engineers, and technical stakeholders responsible for ensuring the integrity and reliability of the software system.

What do you mean by legacy system? Explain its importance.

A legacy system refers to an outdated or obsolete software application, platform, or technology that is still in use within an organization despite being outdated or unsupported by the original vendor. Legacy systems often lack modern features, may be difficult to maintain or extend, and may not meet current business requirements or technological standards.

Importance of Legacy Systems:

1. Business Continuity: Legacy systems often form the backbone of critical business operations, holding vast amounts of historical data and supporting essential functions such as finance, inventory management, and customer relationship management. Maintaining and operating legacy systems ensures the continuity of business operations and prevents disruptions to essential services.
2. Investment Protection: Many organizations have made significant investments in developing, customizing, and integrating legacy systems over time. Despite their age, these systems continue to provide value to the organization, and replacing them entirely may require substantial investments in time, resources, and training. Therefore, maintaining and extending the lifespan of legacy systems helps protect the organization’s investment in existing technology infrastructure.
3. Data Preservation: Legacy systems often contain valuable historical data accumulated over years or decades of operation. Migrating data from legacy systems to newer platforms can be complex, time-consuming, and risky, with potential data loss or corruption. Therefore, preserving and maintaining legacy systems ensures the integrity and accessibility of historical data for regulatory compliance, auditing, reporting, and analysis purposes.
4. Integration with External Systems: Legacy systems may be deeply integrated with other systems, databases, or third-party applications within the organization’s IT ecosystem. Disrupting or replacing these legacy systems could have cascading effects on downstream processes and integrations, leading to compatibility issues, data inconsistencies, or workflow disruptions. Therefore, maintaining legacy systems ensures seamless integration and interoperability with existing IT infrastructure.
5. Regulatory Compliance: In regulated industries such as finance, healthcare, and government, legacy systems may be subject to stringent compliance requirements and industry standards. These systems may have been validated, audited, and certified to meet specific regulatory requirements, and replacing them could entail significant regulatory hurdles and compliance risks. Therefore, maintaining legacy systems helps ensure ongoing compliance with industry regulations and standards.

Draw use case diagram and class diagram for online bus ticketing system.

Explain the behavioral model with example.

In software engineering, the behavioral model refers to a type of model that focuses on describing the dynamic behavior of a software system. It emphasizes how the system responds to various inputs, events, and stimuli, as well as how it transitions between different states or behaviors over time. Behavioral models are commonly used to specify the functional requirements of a system and to illustrate the system’s behavior in response to user interactions or external events.

One popular method for representing behavioral models is through Unified Modeling Language (UML) diagrams, such as use case diagrams, activity diagrams, and state machine diagrams. These diagrams provide visual representations of the system’s behavior, helping stakeholders understand how the system functions and interacts with its environment.

Example: Use case diagram for Library Management System

Explain COCOMO model.

COCOMO (Constructive Cost Model) is a widely used software cost estimation model developed by Barry Boehm in the late 1970s and later extended and refined. COCOMO provides a framework for estimating the effort, time, and resources required to develop a software project based on various factors such as project size, complexity, and development environment. COCOMO is based on empirical data collected from numerous software projects and has evolved into several versions to accommodate different development environments and project characteristics.

There are three main versions of the COCOMO model:

1. Basic COCOMO (COCOMO I): Basic COCOMO is the original version of the model and is primarily used for early-stage rough estimates of software projects. It estimates software development effort as a function of the project size measured in lines of code (LOC). The formula for Basic COCOMO is as follows: Effort (E) = a * (KLOC)^bWhere:
   • E is the effort required to develop the software project.
   • KLOC is the estimated size of the software project in thousands of lines of code.
   • a and b are constants derived from historical data and depend on the project type and development environment.
2.  Intermediate COCOMO (COCOMO II): Intermediate COCOMO extends the basic model by incorporating additional factors that influence software development effort and cost. It introduces different cost drivers that affect the overall project effort, including product, platform, personnel, project, and process attributes. These cost drivers are categorized into various factors such as product complexity, development environment, team experience, and project constraints. The formula for Intermediate COCOMO is more complex than Basic COCOMO and accounts for these additional factors.
3. Detailed COCOMO (COCOMO III): Detailed COCOMO is the most comprehensive version of the model and provides a detailed breakdown of effort estimation by considering individual software development activities and phases. It takes into account factors such as software requirements, design, implementation, testing, and maintenance. Detailed COCOMO allows for a more fine-grained estimation of effort and resources based on specific project characteristics and development methodologies.

Advantages of COCOMO:

• Provides a structured and systematic approach to software cost estimation.
• Accounts for various project factors and attributes that influence development effort.
• Can be tailored to different types of software projects and development environments.
• Relies on empirical data and historical experience, making it more accurate and reliable.
• Helps in early-stage project planning and budgeting, enabling better decision-making and resource allocation.

Disadvantages of COCOMO:

• Requires accurate estimation of project size and other input parameters, which may be challenging, especially for large and complex projects.
• Assumes a linear relationship between project size and effort, which may not always hold true in practice.
• Does not consider factors such as team dynamics, organizational culture, and external dependencies, which can significantly impact project outcomes.
• May not be suitable for projects using modern development approaches such as agile or iterative methodologies, as it is based on traditional waterfall development models.