Software Engineering Notes

Introduction to Software Engineering

Unit A Overview

• Introduction to Software Engineering and Process Models.
• Covers requirements engineering, software design, implementation, testing, and quality.
• Topics include significance, challenges, and software myths.
• Software Development Methodologies: Waterfall, prototyping, incremental, and spiral models.
• Agile process models: Extreme Programming (XP), Adaptive Software Development (ASD), Scrum.

What is Software?

• Software = Program + Documentation + Operating Procedures
• Program: Instructions that provide desired function and performance when executed.
• Documentation: Manuals, analysis/specification, design, implementation, testing details (Context-Diagram, Data Flow Diagrams, Flow Charts, Entity-Relationship Diagram, Source Code Listings, Cross-Reference Listing, Test Data/Results).
• Operating Procedure: Used to set up and operate the software system (System Overview, User Manuals, Operational Manuals, Beginner's Guide, Tutorial, Reference Guide, Installation Guide, System Administration Guide).

Software Engineering Defined

• An engineering discipline concerned with all aspects of software production.
• Involves a systematic and organized approach, using appropriate tools and techniques.
• Aims for quality software delivered on time and within budget, satisfying requirements.
• Software Engineering (SE) applies engineering principles to software development.

Software Engineering vs. Computer Science

• Computer Science: Focuses on theory, fundamentals.
• Software Engineering: Focuses on the practicalities of developing and delivering useful software.
• Computer science theories act as a foundation for software engineering.

Software Engineering vs. System Engineering

• Software engineering is a part of system engineering.
• System engineering includes hardware, software, and process engineering.
• System engineers handle system specification, architectural design, integration, and deployment.

Software Process

• The way in which software is produced.
• A set of activities for software development or evolution.
• Generic activities: Specification, development, validation, evolution.

Product and Process

• Product: What is delivered to the customer (source code, specification document, manuals).
• Process: How software is produced; activities leading to a product.
• An efficient process is required to produce good quality products.

Software Product Types

• Generic: Sold to a range of customers (e.g., word processors).
• Bespoke (Custom): Developed for a single customer according to their specifications (e.g., traffic control system).

Software Characteristics

• Software is engineered/developed, not manufactured.
• Software does not "wear out" like hardware.
• Reusability of components is a key aspect.
• Software is flexible.
• $Failure Rate = f(time)$
• $f(software) \neq f(hardware)$