Lec2- Introduction.pptx

University of Science & Technology Faculty of Computer Science and Information Technology Information Technology Department software Engineering I Dr. Ammar Mohamed Abdo 1 Lec2: Introduction to softwar...

University of Science & Technology Faculty of Computer Science and Information Technology Information Technology Department software Engineering I Dr. Ammar Mohamed Abdo 1 Lec2: Introduction to software Engineering Lec2- Introduction 2 Software process activities  Software specification, where customers and engineers define the software that is to be produced and the constraints on its operation.  Software development, where the software is designed and programmed.  Software validation, where the software is checked to ensure that it is what the customer requires.  Software evolution, where the software is modified to reflect changing customer and market requirements. Lec2- Introduction 3 General issues that affect software  Heterogeneity  Increasingly, systems are required to operate as distributed systems across networks that include different types of computer and mobile devices.  Business and social change  Business and society are changing incredibly quickly as emerging economies develop and new technologies become available. They need to be able to change their existing software and to rapidly develop new software. Lec2- Introduction 4 General issues that affect software  Security and trust  As software is intertwined with all aspects of our lives, it is essential that we can trust that software.  Scale  Software has to be developed across a very wide range of scales, from very small embedded systems in portable or wearable devices through to Internet-scale, cloud-based systems that serve a global community. Lec2- Introduction 5 Software engineering diversity  There are many different types of software system and there is no universal set of software techniques that is applicable to all of these.  The software engineering methods and tools used depend on the type of application being developed, the requirements of the customer and the background of the development team. Lec2- Introduction 6 Application types  Stand-alone applications  These are application systems that run on a local computer, such as a PC. They include all necessary functionality and do not need to be connected to a network.  Interactive transaction-based applications  Applications that execute on a remote computer and are accessed by users from their own PCs or terminals. These include web applications such as e-commerce applications.  Embedded control systems  These are software control systems that control and manage hardware devices. Numerically, there are probably more embedded systems than any other type of system. Lec2- Introduction 7 Application types  Batch processing systems  These are business systems that are designed to process data in large batches. They process large numbers of individual inputs to create corresponding outputs.  Entertainment systems  These are systems that are primarily for personal use and which are intended to entertain the user.  Systems for modeling and simulation  These are systems that are developed by scientists and engineers to model physical processes or situations, which include many, separate, interacting objects. Lec2- Introduction 8 Application types  Data collection systems  These are systems that collect data from their environment using a set of sensors and send that data to other systems for processing.  Systems of systems  These are systems that are composed of a number of other software systems. Lec2- Introduction 9 Software engineering fundamentals  Some fundamental principles apply to all types of software system, irrespective of the development techniques used:  Systems should be developed using a managed and understood development process. Of course, different processes are used for different types of software.  Dependability and performance are important for all types of system.  Understanding and managing the software specification and requirements (what the software should do) are important.  Where appropriate, you should reuse software that has already been developed rather than write new software. Lec2- Introduction 10 Internet software engineering  The Web is now a platform for running application and organizations are increasingly developing web-based systems rather than local systems.  Web services allow application functionality to be accessed over the web.  Cloud computing is an approach to the provision of computer services where applications run remotely on the ‘cloud’.  Users do not buy software buy pay according to use. Lec2- Introduction 11  Web software engineering  Software reuse  Software reuse is the dominant approach for constructing web- based systems. When building these systems, you think about how you can assemble them from pre-existing software components and systems.  Incremental and agile development  Web-based systems should be developed and delivered incrementally. It is now generally recognized that it is impractical to specify all the requirements for such systems in advance. Lec2- Introduction 12 Software engineering ethics Lec2- Introduction 13 Software engineering ethics  Software engineering involves wider responsibilities than simply the application of technical skills.  Software engineers must behave in an honest and ethically responsible way if they are to be respected as professionals.  Ethical behaviour is more than simply upholding the law but involves following a set of principles that are morally correct. Lec2- Introduction 14 Issues of professional responsibility  Confidentiality  Engineers should normally respect the confidentiality of their employers or clients irrespective of whether or not a formal confidentiality agreement has been signed.  Competence  Engineers should not misrepresent their level of competence. They should not knowingly accept work which is outwith their competence. Lec2- Introduction 15 Issues of professional responsibility  Intellectual property rights  Engineers should be aware of local laws governing the use of intellectual property such as patents, copyright, etc. They should be careful to ensure that the intellectual property of employers and clients is protected.  Computer misuse  Software engineers should not use their technical skills to misuse other people’s computers. Computer misuse ranges from relatively trivial (game playing on an employer’s machine, say) to extremely serious (dissemination of viruses). Lec2- Introduction 16 ACM/IEEE Code of Ethics  The professional societies in the US have cooperated to produce a code of ethical practice.  Members of these organisations sign up to the code of practice when they join.  The Code contains eight Principles related to the behaviour of and decisions made by professional software engineers, including practitioners, educators, managers, supervisors and policy makers, as well as trainees and students of the profession. Lec2- Introduction 17 Rationale for the code of ethics  Computers have a central and growing role in commerce, industry, government, medicine, education, entertainment and society at large. Software engineers are those who contribute by direct participation or by teaching, to the analysis, specification, design, development, certification, maintenance and testing of software systems.  Because of their roles in developing software systems, software engineers have significant opportunities to do good or cause harm, to enable others to do good or cause harm, or to influence others to do good or cause harm. To ensure, as much as possible, that their efforts will be used for good, software engineers must commit themselves to making software engineering a beneficial and respected profession. Lec2- Introduction 18 The ACM/IEEE Code of Ethics Software Engineering Code of Ethics and Professional Practice ACM/IEEE-CS Joint Task Force on Software Engineering Ethics and Professional Practices PREAMBLE The short version of the code summarizes aspirations at a high level of the abstraction; the clauses that are included in the full version give examples and details of how these aspirations change the way we act as software engineering professionals. Without the aspirations, the details can become legalistic and tedious; without the details, the aspirations can become high sounding but empty; together, the aspirations and the details form a cohesive code. Software engineers shall commit themselves to making the analysis, specification, design, development, testing and maintenance of software a beneficial and respected profession. In accordance with their commitment to the health, safety and welfare of the public, software engineers shall adhere to the following Eight Principles: Lec2- Introduction 19 Ethical principles 1. PUBLIC - Software engineers shall act consistently with the public interest. 2. CLIENT AND EMPLOYER - Software engineers shall act in a manner that is in the best interests of their client and employer consistent with the public interest. 3. PRODUCT - Software engineers shall ensure that their products and related modifications meet the highest professional standards possible. 4. JUDGMENT - Software engineers shall maintain integrity and independence in their professional judgment. 5. MANAGEMENT - Software engineering managers and leaders shall subscribe to and promote an ethical approach to the management of software development and maintenance. 6. PROFESSION - Software engineers shall advance the integrity and reputation of the profession consistent with the public interest. 7. COLLEAGUES - Software engineers shall be fair to and supportive of their colleagues. 8. SELF - Software engineers shall participate in lifelong learning regarding the practice of their profession and shall promote an ethical approach to the practice of the profession. Lec2- Introduction 20 Case studies Lec2- Introduction 21 Ethical dilemmas  Disagreement in principle with the policies of senior management.  Your employer acts in an unethical way and releases a safety-critical system without finishing the testing of the system.  Participation in the development of military weapons systems or nuclear systems. Lec2- Introduction 22