Software Engineering Course Overview

Introduction to Software Engineering

• This course introduces software engineering, covering its challenges, processes, and contents.
• The course aims to help students avoid pitfalls and myths in software design.
• It also covers different software processes for suitable selection and designing high-quality, efficient, usable, and maintainable software.

Course Objectives

• Learn about challenges in software development to prevent pitfalls and misconceptions.
• Learn about various software processes to choose appropriate approaches.
• Design high-quality software capable of efficient operation and maintenance.
• Understand advanced software engineering methods.

Course Contents

• Introduction to software engineering
• Software processes
• Requirements engineering
• Software design
• Object-oriented software development
• Software testing and verification
• Software project management
• Advanced methods

Chapter 1: Introduction to Software Engineering

• Provides an overview of software engineering, including the software crisis, myths, methods, evolution, and current status.

Contents

• Software crisis
• Software myths
• What is software engineering
• Evolution of software engineering
• State-of-the-art in software engineering

Statistics - Chaos Report (1995)

• 365 IT executives surveyed 8,380 projects
• Average time overrun: 222%
• Average cost overrun: 189%
• 189% of original budget
• 221% of original schedule
• 61% of original functionality
• 61% of specified features included
• 16% of projects completed on time and on budget
• 31% cancelled before completion

Symptom of Software Crisis

• Annual US spending on application development is approximately $250 billion.

• $140 billion wasted due to project abandonment or rework.

• Poor practices contributing to problems.

• 10% of client/server applications are abandoned or restarted from scratch.

• 20% of applications are significantly altered to avoid disaster.

• 40% of applications are delivered significantly late.

• Study of 70 large client/server applications from 30 European firms.

Observed Problems

• Software products fail to meet user requirements.
• Software products crash frequently.
• Software products are expensive.
• Software products are difficult to alter, debug, enhance, and often delivered late.
• Software products use resources non-optimally.

Why are the Statistics So Bad?

• Misconceptions about software development.
• Software myths (e.g., the man-month myth).
• Incorrect assumptions.
• Inability to distinguish between coding and software development.
• Exponential growth in complexity and difficulty with software size.
• Ad hoc approaches break down with increasing software size.
• Software professionals lacking engineering training.
• Programmers with programming skills but without engineering mindset/process discipline.
• Internal complexities
• Essences and accidents in software development.

How is Software Usually Constructed?

• Illustrates the common misconceptions in software construction with a graphical representation depicting how requirements are often misrepresented, leading to different and misaligned end products.

Software Myths (Customer Perspectives)

• General statements of objectives suffice for software development initiation.
• Missing/vague requirements can easily be dealt with later.
• Application requirements are never stable; software must be flexible enough to accommodate changes.

Software Myths (Developer Perspectives)

• The job is done when the software is demonstrated.
• Problems only begin after demonstration.
• Software quality cannot be assessed before coding and testing.
• Bugs accumulate during development.

Software Myths (Management Perspectives)

• Good standards and procedures suffice for successful software development.
• Proof of success is found in the product's use, not just the development process.
• The environment alone does not determine the quality of the product.
• Adding more specialists won't always solve schedule slip problems.

Misplaced Assumptions

• All requirements can be pre-specified.
• Users are experts at specifying their needs.
• Users and developers are equally good at visualization.
• Project teams can communicate unambiguously.

Confused with Programs and Products

• Programs are typically small, with the author being the sole user (e.g. small personal software).
• Software products are large, with multiple users.
• Professional software development involves teams.
• Large products have well-designed interfaces, well-documented processes, and systematic development methods.
• Small programs often lack proper user interfaces, documentation, and systematic development.

Software Programming ≠ Software Engineering

• Software programming involves translating problems into computer understandable language.
• Software engineering involves developing, managing, evolving software products with teams of developers, complex systems, indefinite lifespan, and numerous stakeholders.

What is Software?

• Software is a combination of programs, documents, and data that form a configuration with programs designed to perform desired actions based on provided data. It also consists of documents to elaborate the operation and use of programs.

• Software is an intangible, dynamic model of reality encompassing behaviors, real-world scenarios, computers, and auxiliary equipment interacting on the real world, which is constantly changing.

Unique Characteristics of Software

• Malleable (changeable)
• Human-intensive (demands significant human effort)
• Intangible and difficult to measure
• Complex problems
• Depends deeply on hardware (directly linked)
• Top in the system engineering "food chain".
• Does not wear out, but deteriorates (maintaining it is important if it is constantly used)
• Requires high rigor in solutions
• Has a discontinuous operational nature (on/off type functionality)

Casting the Term

• Software engineering emerged from NATO conferences in 1968 to address issues connected with project failures.

What is Software Engineering?

• The application of systematic, disciplined, quantifiable approaches to software; that is, the application of engineering to software.

What is Software Engineering? (ctd.)

• Concerned with the theories, methods, and tools used for software development, maintenance, and evolution.
• Aims to produce quality software on time, within budget, and satisfying users' needs.
• Deals with large software systems developed by teams.
• Practical application of scientific knowledge to design, construct, and maintain computer programs and documentation.

Other Definitions of Software Engineering

• A systematic approach to software analysis, design, implementation, and maintenance (free online dictionary definition).
• Systematic application of tools and techniques (development of applications).
• Design and development of high-quality software.

Scope and Goals of Software Engineering

• Scope: study of software processes, development principles, techniques, and notations
• Goals: production of quality software, delivered on time and within budget, satisfying customer needs.

Software Process

• Waterfall life cycle
• Prototyping
• Spiral model
• Automatic synthesis model
• Object-oriented model
• 4 GL model

Traditional Software Engineering

• Focuses on functions, data, and behavior represented by data flow diagrams, entity-relationship diagrams, and state transition diagrams.

Object-Oriented Software Engineering

• Focuses on objects, functions, and behavior represented by class diagrams, data flow diagrams, and state charts.

Evolution of Software Industry

• Independent programming services
• Software products
• Enterprise solutions
• Packaged software for the masses
• Internet software and services

Evolution of Design Techniques

• Ad hoc
• Data structure based
• Control flow based
• Object oriented

Related Knowledge

• Application domain knowledge
• Specialized SE knowledge
• Advanced SE knowledge

IT Market

• Hardware products
• Hardware maintenance
• Software (embedded, professional, software products, packaged mass-market, enterprise solutions)
• Processing services and Internet services

Software Products and Services

• A list of companies/products associated with the different software categories (professional services, enterprise solutions, packaged, and mass-market software)

Software Engineering Today?

• Organizations rely on past practices.
• Difficulty in effectively training people on today's software processes leads to 'institutionalized' ineffective practices.
• Few people are capable of integrating best software practices or adopting proven methodologies.

Not Crisis, but a Chronic Problem

• Software issues persist, even after 35 years.
• Major problems remain, such as poor quality, budget overruns, and late or missed delivery dates.

What's Wrong?

• Software engineering has made progress but some areas still suffer from the issues of unrealistic expectations regarding delivering, maintainable, and quality software.

A More Close Look

• Comparing 1995 and 2003 reports indicates some progress.

So, What's the Problem?

• Issues change with the software industry.
• Increasing emphasis on methods and tools, but insufficient education and training on techniques.
• Lack of known proven software practices.

Software Changes in the Past Years

• Software size increased drastically.
• Operating environments became more complex (e.g., batch, time-sharing, distributed systems).
• Software development has become equally complex as operating systems.

Situations for Software are Different Too

• Intense market forces and unrealistic delivery time schedules.
• Rapidly changing requirements.
• Pressure for faster time to market.
• Evolving software methodologies, systems, and techniques.
• Need to re-design major systems.

Talent Shortages and Constant Evolution

• Software engineering talent is often in short supply.
• Moore's law and software complexity make it necessary to constantly adapt to new methods and techniques
• Trial and error is common to find software design limits.

The Software Industry Today

• Current state shows some progress, yet it is not much better than before due to the urgency of schedules and rapid evolution.
• Need to improve understanding of how to improve overall production.

Future of SE

• Future areas of focus for software engineering (process, requirements engineering, testing, reverse engineering, maintenance, software architecture, OO modeling, SE and middleware tool and environment, configuration management, databases, SE education) with different categories (analysis, formal specifications, and foundations), alongside detailed principles, concepts and considerations.

Three Key Challenges

• Legacy systems
• Heterogeneity
• Software delivery

Ever-Present Difficulties

• Lack of guiding scientific principles.
• Lack of universally applicable methods.
• Importance of managerial, psychological, and sociological aspects alongside tech aspects.

Test your knowledge about the objectives and key insights from the software engineering course. This quiz covers various aspects such as project management, software processes, and quality assurance. Engage with questions that highlight the challenges and improvements in the field of software engineering.