Dillon: CSE470: INTRO1 Introduction to Software Engineering Computer Science and Engineering 470

Dillon: CSE470: INTRO2 What is Software Engineering ??? l The study of systematic and effective processes and technologies for supporting software development and maintenance activities  Improve quality  Reduce cost

Dillon: CSE470: INTRO3 Historical Perspective l 1940s: computers invented l 1950s: assembly language, Fortran l 1960s: COBOL, ALGOL, PL/1, operating systems 1969: First conference on S/W Eng l 1970s: multi-user systems, databases, structured programming

Dillon: CSE470: INTRO4 Historical Perspective (cont.) l 1980s: networking, personal computing, embedded systems, parallel architectures l 1990s: information superhighway, distributed systems, OO l 2000s: virtual reality, voice recognition, video conferencing, global computing,...

Dillon: CSE470: INTRO5 Hardware Costs vs Software Costs (% of overall costs) s/w costs h/w costs

Dillon: CSE470: INTRO6 Why is software so expensive? l Hardware has made great advances l But, software has made great advances... l Do the least understood tasks in software l When task is simple & understood, encode it in hardware l Demand more and more of software

Dillon: CSE470: INTRO7 Size of programs continues to grow l Trivial: 1 month, 1 programmer, 500 LOC, Intro programming assignments l Very small: 4 months, 1 programmer, 2000 LOC Course project l Small: 2 years, 3 programmers, 50K LOC Nuclear power plant, pace maker l Medium: 3 years, 10s of programmers, 100K LOC Optimizing compiler

Dillon: CSE470: INTRO8 Size of programs continues to grow l Large: 5 years, 100s of programmers, 1M LOC MS Word, Excel l Very large: 10 years, 1000s of programmers, 10M LOC Air traffic control, Telecommunications, space shuttle

Dillon: CSE470: INTRO9 Goals of this Course l Expose you to some of the problems typically encountered in s/w eng l Expose you to some of the techniques that have been found to be effective Requires more rigor Often appears “obvious” (but only after being learned )

Dillon: CSE470: INTRO10 What’s the problem? l Software cannot be built fast enough to keep up with »H/W advances »Rising expectations »Feature explosion l Increasing need for high reliability software

Dillon: CSE470: INTRO11 What’s the problem? l Software is difficult to maintain “aging software” l Difficult to estimate software costs and schedules l Too many projects fail »Arianne Missile »Denver Airport Baggage System

Dillon: CSE470: INTRO12 Why is software engineering needed? l To predict time, effort, and cost l To improve software quality l To improve maintainability l To meet increasing demand l To lower software costs l To successfully build large, complex software systems