Software Development Methodologies

Study Notes

Exploratory Development

Aims to collaborate with customers to develop a final system from an initial outline specification.
Begins with well-understood requirements and evolves by adding customer-proposed features.

Throw-away Prototyping

Focuses on clarifying poorly understood system requirements.
Initial prototypes created are discarded after understanding the necessary features.

Evolutionary Development

Problems include lack of process visibility and poorly structured systems.
May require special skills for rapid prototyping.
Suited for small to medium-sized interactive systems or specific parts of larger systems.

Component-based Software Engineering

Emphasizes systematic reuse by integrating existing components or commercial-off-the-shelf (COTS) systems.
Key process stages: Component analysis, requirements modification, system design with reuse, and development/integration.
Growing trend due to emerging component standards.

Reuse-oriented Development

Focuses on maximizing the reuse of existing software components to enhance efficiency.

Process Iteration

System requirements evolve throughout the project; iteration involves revisiting earlier stages.
Applicable to all generic process models.
Associated approaches include incremental delivery and spiral development.

Incremental Delivery

Breaks development into increments rather than a single delivery.
Prioritizes user requirements, focusing on high-priority needs first.
Requirements are frozen once an increment's development starts, though later increments can adapt.

Incremental Development Advantages

Delivers customer value with each increment; functionality becomes available sooner.
Early increments serve as prototypes for future requirements.
Reduces overall project failure risk, with more testing focused on high-priority services.

eXtreme Programming (XP)

A development approach characterized by very small functional increments.
Encourages constant code improvement, active user involvement, and pair programming.

Spiral Development

Represents the process as a spiral with phases not fixed, allowing for flexibility.
Each loop represents a phase where risks are assessed and resolved continuously.

Spiral Model Sectors

Objective setting: Define specific phase goals.
Risk assessment and reduction: Identify and mitigate key risks.
Development and validation: Choose a suitable development model.
Planning: Review project and plan the next spiral phase.

Process Activities

Include software specification, design, implementation, validation, and evolution.

Software Specification

Involves defining necessary services and system constraints.
The requirements engineering process consists of feasibility study, requirements elicitation/analysis, specification, and validation.

Software Design and Implementation

Converts specifications into an executable system.
Activities are closely related and often interleaved, covering architectural design, interface design, and algorithm design.

Structured Methods

Systematic approaches involving understanding the problem domain and designing systems.
Three phases: Elaboration (understanding), Construction (design, programming, testing), and Transition (deployment).

RUP Good Practices

Emphasizes iterative development, effective requirement management, use of component architectures, visual modeling, verification of quality, and change control.

Static Workflows

Business modeling, requirements development, analysis and design, implementation, testing, deployment, configuration/change management, and project management are crucial workflows in software development.

Computer-Aided Software Engineering (CASE)

Tools designed to support software development processes through activity automation.
Includes graphical editors, debugging tools, data management, and code generation.

CASE Technology Impacts

Though improvements in the software process have been realized, they are less significant than initially expected due to the need for creativity and team collaboration in software engineering.

CASE Classification

Functional perspective: Classifies tools based on specific functions.
Process perspective: Classification based on supported process activities.
Integration perspective: Classification based on organization into integrated units.

Functional Tool Classification

Includes various tools for planning, editing, change and configuration management, prototyping, and testing.

Activity-Based Tool Classification

Categorizes tools according to their support in specification, design, implementation, and verification.

CASE Integration

Tools support individual tasks while workbenches aid specific process phases.
Environments encompass multiple integrated workbenches covering extensive parts of the software process.

Key Points on Software Processes

Software processes involve a sequence of activities for producing and evolving software systems.
Software process models generalize activities such as specification, design, implementation, validation, and evolution.
Iterative models depict cycles of activities, with examples including the waterfall model and evolutionary development.
Requirements engineering is essential for developing software specifications, and the rational unified process separates activity from phases.
CASE technologies significantly support these software process activities.