Fundamental of software engineering: Introduction

Introduction

• What is software? Not hardware, procedure documentation, data
• Type of application: application, system
• Craft (hacking) + science (computer science) + engineering (software engineering)
• Software engineering :
• real products for real people
• based on scientific principle
• require academic background
• repeatable, well-defined procedures and processes.

Origin

• Definition: the establishment and use of sound engineering principles in order to obtain economically software that is reliable and works efficiently on real machine.
• Software crisis: late and over-budget, poor quality, code hard to maintain, customers and users not happy, project difficult to manage. ⇒ complexity

Complexity

• Numbers of interactions between lines of code
• Moore’s law: density of transistors on a chip will double every two or so years
• corollaries: RAM size in a computer, hard drive space in a computer, internet bandwidth.
• Complexity trend:
• max line of code: n = 2^t
• max interaction: n =n*(n-1)/2

Goals and Principles

• Goals: modifiability, efficiency, reliability, usability
• Principles:
• modularity (reduce complexity, divide and conquer)
• abstraction
• encapsulation (high cohesion, low coupling)
• 4c (correct, complete, consistent, confirmable)

Is software engineering a profession

• Organization: ACM, IEEE-CS