Software Development Models

Advanced Systems Development Principles

• Software development follows specific models to streamline the process

Software Development Models

• Software Development Life Cycle (SDLC) phases include Planning, Analysis, Design, Implementation, Testing, Deployment, and Maintenance
• The Waterfall model is best for well-defined projects due to its linear and rigid structure
• The Agile model is iterative, flexible, provides continuous feedback, and encourages customer collaboration
• The Spiral model is risk-driven, iterative, and suitable for large projects with evolving requirements
• The V-Model focuses on validation and verification at each phase for structured projects
• DevOps (CI/CD) enables Continuous Integration & Continuous Deployment for automation and faster releases

System Architecture and Integration

• Principles of System Architecture include Scalability, High Availability, Fault Tolerance, and Performance Optimization
• Security best practices include Authentication, Encryption, Access Control, and Multi-Factor Authentication (MFA)
• Point-to-Point (P2P) integration involves a direct system-to-system connection
• Enterprise Service Bus (ESB) is a centralized integration hub for multiple applications
• Event-Driven Architecture (EDA) allows Asynchronous communication for real-time processing
• The API-First Approach uses RESTful API-based integration for flexibility
• ETL (Extract, Transform, Load) is used for large-scale data integration and analytics

System Deployment and Cloud Computing

• Containerization (Docker) differs from Virtualization (Virtual Machines or VMs)
• Infrastructure as Code (IaC) automates deployment using Terraform and AWS CloudFormation
• Cloud Computing Models include Public, Private, and Hybrid Cloud options
• Performance Optimization Strategies involve Load Balancing, Database Replication, and Caching

Requirements Analysis and Engineering

• It focuses on identifying and defining what a system should do and how it should perform

Types of Requirements

• Functional Requirements define what the system should do, such as user authentication, reporting, and transactions
• Non-Functional Requirements define how the system should perform, including aspects like security, scalability, and usability
• Technical Requirements cover infrastructure, database, and software dependencies
• Business Requirements are linked to the business goals that guide system development
• Regulatory & Compliance Requirements adhere to industry standards, security policies, and legal constraints

Requirements Gathering Techniques

• Interviews involve one-on-one discussions with stakeholders
• Surveys & Questionnaires collect structured responses from users
• Observation involves watching users interact with existing systems
• Document Analysis includes reviewing existing system documents and reports
• Prototyping involves building a functional model for early user feedback
• Focus Group Discussions (FGD) engage stakeholders to discuss system needs

Requirements Engineering Process

• A Feasibility Study assesses if the project is technically, operationally, and economically viable
• Requirements Elicitation involves gathering system requirements from stakeholders
• Requirements Specification documents requirements in a structured format (e.g., Software Requirements Specification - SRS)
• Requirements Validation ensures accuracy, completeness, and consistency of requirements
• Requirements Management focuses on tracking and controlling changes to requirements throughout the project

Requirements Prioritization Methods

• MOSCOW Method categorizes requirements as Must-have, Should-have, Could-have, and Won't-have
• The Kano Model categorizes basic, performance, and exciting requirements
• Cost-Benefit Analysis evaluates feasibility based on cost vs. value

Challenges in Requirements Engineering

• Ambiguous Requirements arise from unclear expectations from stakeholders
• Conflicting Stakeholder Needs involve balancing different business and user priorities
• Evolving Requirements involve handling changes during development without project delays
• Overlooking Non-Functional Requirements involves ensuring security, performance, and usability are defined

Architectural Modeling and Design

• It involves creating models and patterns to design software architecture

System Modeling Techniques

• Structural Models use class diagrams and component diagrams
• Behavioral Models use case diagrams and sequence diagrams
• Functional Models use data flow diagrams (DFDs)
• Data Models use Entity-Relationship Diagrams (ERDS)
• Physical Models use deployment diagrams and network topology diagrams

Software Architecture Patterns

• Layered Architecture organizes software into Presentation, Business Logic, and Data layers
• Client-Server Architecture separates the frontend (client) from the backend (server)
• Microservices Architecture uses independent, modular services that communicate via APIs
• Event-Driven Architecture (EDA) enables asynchronous, event-based message processing
• Model-View-Controller (MVC) separates UI, logic, and data handling
• Master-Slave Architecture has a master system controlling multiple slaves for parallel processing

High-Level System Design Principles

• System Architecture Planning involves designing system components and their interactions
• Data Flow Diagrams (DFDs) visualize data movement across the system
• Interface Design defines APIs and system interactions
• Technology Stack Selection involves choosing programming languages, frameworks, and databases
• Deployment Architecture includes cloud hosting, on-premises servers, and hybrid models

Security and Performance Considerations in Architecture

• Authentication & Authorization involves Multi-Factor Authentication (MFA) and Role-Based Access Control (RBAC)
• Encryption Mechanisms use secure communication using TLS, SSL, and database encryption
• Logging and Monitoring tracks system activities for security and auditing
• Load Balancing & Database Replication involves distributing traffic and maintaining data redundancy