7M822 Software Engineering Introduction 7 September 2010

7M822 Software Engineering – Why ? Software problems –Bugs: low quality –High cost: budget overrun –Late delivery: schedule overrun

7M822 Software Engineering – Goal Make quality software, on time, within budget –Large and complex systems –Exist in may versions and variants –Last for many years in a changing environment –Undergo frequent changes –Built by project teams

7M822 What is software engineering? SE is an engineering discipline which is concerned with all aspects of software production – implied a systematic and organised approach to the development operation, and maintenance of software

7M822 Software Engineering vs. System Engineering System engineering is concerned with all aspects of computer-based systems development including hardware, software and process engineering Software engineering is part of this process

7M822 What is software Computer programs and associated documentation

7M822 Nature of software Intangible Easy to modify Trivial replication Labor-intensive

7M822 Types of software Software products may be developed for a particular customer or may be developed for a general market –Custom –Generic –Embedded

7M822 Another categorization of software Real time software –It has to react immediately to stimuli from the environment Data processing software –Is used to run business

7M822 Stakeholders in software engineering Users Customers (clients) Software developers Development managers

7M822 Quality Software Customer: solves problems at an acceptable cost in terms of money paid and resources used User: easy to learn; efficient to use; and helps get work done Developer: easy to design; easy to maintain; and easy to reuse parts Development manager: sells more and pleases customers while costing less to develop and maintain

7M822 Software Quality Usability Efficiency Reliability Maintainability Reusability

7M822 Software process A structured set of activities required to develop a software system Generic activities in all software processes are –Specification –Design –Validation –Evolution

7M822 Compare SE with building a house Search for a location What type of house Make a design (architect) Design  drawings Realise house Completion of the house Use of the house

7M822 References Sommerville, Ian (2001) Software Engineering, 6 th edition Timothy Lethbridge & Robert Laganière (2005) Object-Oriented Software Engineering, 2 nd edition