Introduction to Software EngineeringWhat is a Software?Attributes of Good SoftwareSoftware CrisisSome FactsImportance of SWEWhat is Software Engineering?The Big PictureSWE vs. Computer ScienceSWE vs. System EngineeringWhat is a Software Process (SP)?What is a Software Process Model (SPM)?What is CASE?Key Challenges Facing Software EngineeringSummaryJan 14, 2019Introduction to SWE 1Introduction toSoftware Engineering Softwares Importance of SWE  Basic SWE ConceptsJan 14, 2019Introduction to SWE 2What is a Software?Software is a computer program with its documentation such as requirements, design models and user manuals.Software products may beGeneric - developed to be sold to a range of different customers e.g. general PC software such as Excel or Word.Bespoke (custom, tailored) - developed for a single customer according to their specification.Jan 14, 2019Introduction to SWE 3Attributes of Good SoftwareA good software shoulddeliver the required functionality and performance to the user be maintainable: can be evolved to meet changing needs;be dependable: reliable and trustworthybe efficient : should not waste the system resourcesbe acceptable by end-user, i.e., usable, understandable and compatible with other systems.Jan 14, 2019Introduction to SWE 4Software CrisisThe notion of software engineering was first proposed in 1968 at a conference to discuss what was then called ‘software crisis’:Informal (ad-hoc) software developmentMajor projects were sometimes years late and over budget, Softwares were unreliable, difficult to maintain and performed poorly.Jan 14, 2019Introduction to SWE 5Some FactsFailed software projects in USA costs $81 bn annually.http://www.it-cortex.com/Stat_Failure_Rate.htmFailure can be severe and expensive.Problems may happen during any stage of the Software development life-cycle.Purpose of SWE is to avoid problems and hence failureJan 14, 2019Introduction to SWE 6Importance of SWEThe economies of ALL developed nations depends (somehow) on software.More and more systems are software controlledSoftware cost often dominate computer system costs. The costs of software on a PC are often greater than the hardware cost.SWE develop theories, methods and tools that help to build cost-effective and high-quality software.Jan 14, 2019Introduction to SWE 7What is Software Engineering?SWE is an engineering discipline that is concerned with all aspects of software production.Software engineers should adopt a systematic and organised approach to their work, use appropriate tools and techniques depending on the problem to be solved (the development constraints + the resources available.)Jan 14, 2019Introduction to SWE 8The Big PictureComputer ScienceComputer EngineeringSystem EngineeringSoftware EngineeringScience is Theory Engineering is more practicalSoftware  Computer  SystemJan 14, 2019Introduction to SWE 9SWE vs. Computer ScienceComputer science is concerned with theory and fundamentalsSWE is concerned with the practicalities of developing and delivering useful software.Computer science theories are still insufficient to act as a complete foundation for software engineering.Jan 14, 2019Introduction to SWE 10SWE vs. System EngineeringSystem engineering is concerned with all aspects of computer-based systems development including hardware, software and process engineering. SWE is part of the process concerned with developing the software infrastructure, control, applications and databases in the system.System engineers are involved in system specification, architectural design, integration and deployment.Jan 14, 2019Introduction to SWE 11What is a Software Process (SP)?SP is a set of activities whose goal is the development or evolution of software.General activities in all SPs are:Specification: what should the system do and what are its development constraints?Development: production of the softwareValidation: checking that the software is what the customer wantsEvolution: changing the software in response to changing demands.Jan 14, 2019Introduction to SWE 12What is a Software Process Model (SPM)?SPM is a simplified representation of a software process, presented from a specific perspective such asWorkflow perspective: sequence of activities;Data-flow perspective: information flow;Role/action perspective: who does what.Examples of generic SPMWaterfallIterative developmentComponent-based software engineeringJan 14, 2019Introduction to SWE 13What is CASE?CASE (Computer-Aided Software Engineering) are software systems that are intended to provide automated support for software process activities. CASE are often used for method support.Upper-CASE: support the early process activities of requirements and design;Lower-CASE: support later activities such as programming, debugging and testing.Jan 14, 2019Introduction to SWE 14Key Challenges Facing Software EngineeringHeterogeneity: developing techniques for building software that can cope with heterogeneous (different) platforms and execution environmentsDelivery: developing techniques that lead to faster delivery of softwareTrust: developing techniques that demonstrate that software can be trusted by its users.Jan 14, 2019Introduction to SWE 15SummarySWE is an engineering discipline that is concerned with all aspects of software production.Software products consist of developed programs and associated documentation. Essential product attributes are maintainability, dependability, efficiency and acceptability.SP consists of activities that are involved in developing softwares. Basic activities are software specification, development, validation and evolution.CASE tools are software systems which are designed to support routine activities in the