《软件工程》Computer Science 上.ppt

Computer Science 3061/15/03 Bill Bond Class Communication Email your name and email address to bondw@ Normally will post notes before class Assignments got to bondw@ Web page should be in following location: /~umreec/web-courses/ Software Crisis Programs don’t reflect customer desires Schedule and cost estimates are often grossly inaccurate “Productivity” of software people has not kept pace with the demand for their services Software complexity increases Quality of software is sometimes less than adequate Difficult to maintain existing programs The Problem Building computer solution is hard Understand problem Design solution Implement solution Complexity is the problem Lots to do Lots to keep track of Software Engineering Managing complexity by imposing discipline Abstraction - focus only on essential details, ignore others (for now) Decomposition - break into manageable pieces Analysis/Design methods and Tools support these ideas Large Projects Require Teams Key elements Communication - has cost Artifacts - support communication Artifacts Which should be produced? “Discovery” value Which should be maintained? Maintenance value Recognize cost of producing artifacts Software Engineering Book definition – The establishment and use of sound engineering principles in order to obtain economical software that is reliable and works efficiently on real machines Result Comprehensive methods – “how to” Process – context in which technical methods applied, deliverables produced Better tools More powerful building blocks Better quality assurance Communication Three Generic Phases Definition phase What Information to be processed Function/Performance desired System Engineering Software Project Planning Requirements Analysis Three Generic Phases, cont Development phase – how Software architecture Implementation Testing Three Generic Phases, cont Maintenance phase – change Correction – defect correction Adaptation – supports new environment Enhancement Prevention – changes