Questions
4 questions per paper
Difficulty
Medium
Importance
Medium yield — focus on core definitions
Overview
Software Engineering and System Design cover the processes and architectural decisions behind building reliable, scalable software. For PSU exams, this topic is critical as it tests your theoretical understanding of development lifecycles and modern architectural paradigms often used in large-scale industrial systems.
SDLC Models: Waterfall and Agile
The Software Development Life Cycle (SDLC) defines the stages of software creation, with Waterfall being linear and Agile being iterative. PSUs frequently ask about the sequential nature of Waterfall versus the customer-centric, flexible nature of Scrum or XP within Agile.
- Waterfall is document-driven and lacks backtracking flexibility
- Agile methodologies emphasize working software over comprehensive documentation
- Scrum roles: Product Owner, Scrum Master, and Team
- Waterfall is best suited for projects with fixed requirements
- Agile utilizes Sprints typically lasting 2 to 4 weeks
Software Testing Levels
Testing ensures quality by identifying defects at various stages of the development process. Understanding the hierarchy from individual module checks to complete environment validation is a staple of technical objective papers.
- Unit testing validates individual components by developers
- Integration testing focuses on the interface between modules
- System testing verifies the software against functional requirements
- Acceptance testing is the final phase performed by the user
- White-box testing focuses on internal logic and code structure
UML and Design Patterns
Unified Modeling Language (UML) provides standard visual representations of software architecture, while design patterns offer reusable solutions to common problems. Examiners test your ability to recognize specific diagrams or the purpose of common patterns.
- Use Case Diagrams represent system functionality from a user perspective
- Class Diagrams illustrate the static structure of the system
- Singleton pattern ensures a class has only one instance
- Observer pattern is used for event-driven distributed systems
- Factory pattern provides an interface for creating objects in a superclass
Microservices and REST APIs
Modern system design often shifts from monoliths to microservices, utilizing REST APIs for inter-service communication. You must understand how these distributed components communicate via standardized web protocols.
- REST uses HTTP methods: GET, POST, PUT, DELETE
- Microservices promote independent deployability and scalability
- Statelessness is a core constraint of the REST architectural style
- JSON is the primary data exchange format for REST APIs
- API Gateways act as the single entry point for microservice clusters
Exam Tip
Focus on memorizing the core characteristics and key terminologies of each SDLC model, as PSU questions are usually direct and definition-based.
Common Mistakes
- Confusing the order of SDLC phases in the Waterfall model
- Misidentifying the purpose of specific UML diagrams in exam scenarios
- Overlooking the difference between white-box and black-box testing techniques
More Revision Notes
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