Introduction to Software Development

Lecture 2 investigates the primary activities involved throughout the software development process. Development activities are broadly divided into two major complementary categories: construction activities and management activities. Construction activities directly produce the software deliverable and include requirements gathering, system analysis, architectural and detailed design, coding, testing, and deployment. Management activities complement and govern construction, encompassing project planning, cost estimation, resource scheduling, risk management, quality assurance, configuration control, and progress tracking. Students examine the critical balance required between technical construction and structured process management, analyzing how disciplined workflows prevent chaotic ad-hoc development, reduce defect leakage, and guarantee predictable engineering delivery. Key concepts such as source and sink analysis, context boundaries, and external data interfaces are rigorously analyzed in system modeling scenarios. Use case modeling techniques demonstrate how primary actors, preconditions, postconditions, and alternative execution flows document user interactions. State transition diagrams illustrate how event-driven systems transition between operational states in response to external triggers and guard conditions. The lecture contrasts traditional sequential lifecycle models like the Waterfall model against iterative, prototyping, and risk-driven evolutionary approaches. Software design principles emphasize high cohesion and low coupling to minimize ripple effects and enhance long-term system maintainability. Coupling classifications, spanning content, common, control, stamp, and data coupling, are critically evaluated to eliminate structural dependencies. Cohesion levels, from coincidental and logical to communicational and functional cohesion, provide objective criteria for evaluating module quality. Object-oriented analysis using the Coad and Yourdon methodology illustrates identifying classes, responsibilities, attributes, and services. Structural relationships, including Generalization-Specialization inheritance hierarchies and Whole-Part aggregation assemblies, are modeled with precision. Dynamic interaction modeling demonstrates sequence diagrams, object lifelines, activation bars, and synchronous versus asynchronous message exchanges. Software architecture frameworks explore Kruchten's 4+1 view model, connecting logical, process, development, and physical architectural perspectives. Architectural styles, including layered hierarchies, repository patterns, client-server structures, and pipe-and-filter pipelines, are contrasted. Design pattern principles demonstrate how Gang of Four solutions, such as the Observer pattern, decouple subjects from observers to handle state changes.