6/10/20151 Introduction to Software Engineering

6/10/20152 Programming versus Software Engineering l programming 1. The process of translating a problem from its physical environment into a language that a computer can understand and obey. (Webster’s New World Dictionary of Computer Terms) 2. The art of debugging a blank sheet of paper. 3. A pastime similar to banging one's head against a wall, but with fewer opportunities for rewards. (2 and 3 from The New Hacker’s Dictionary) l software engineering (according to Fritz Bauer) “The establishment and use of sound engineering principles in order to obtain economically software that is reliable and works efficiently on real machines.”

6/10/20153 Other Definitions of Software Engineering l “A systematic approach to the analysis, design, implementation and maintenance of software.” (The Free On-Line Dictionary of Computing) l “The systematic application of tools and techniques in the development of computer-based applications.” (Sue Conger in The New Software Engineering) l “Software Engineering is about designing and developing high-quality software.” (Shari Lawrence Pfleeger in Software Engineering -- The Production of Quality Software)

6/10/20154 Software Engineering is Nothing New In 1945 George Polya Published a Book Called How to Solve It Outlining Four Steps in Problem Solving. 1. Understand the Problem (Requirements Analysis) 2. Devise a Plan (Software Design and Implementation Plan) 3. Carry out the Plan (Coding) 4. Look Back (Testing the Solution)

6/10/20155 Development Costs Analysis by Capers Jones (1981)

6/10/20156 The Origin of Software Defects

6/10/20157 Maintenance Costs

6/10/20158 Development Schedules For Large Systems –25% are canceled before completion –60% experience significant cost and schedule overruns –75% of completed systems experience major problems –Less than 1% finish on time, within budget, and satisfy user needs –The mode is to finish over a year late and cost almost twice original estimates