1. Introduction to Software Engineering
Attributes of Software-Intensive Systems
Software Engineering Definitions
Software Engineering as a Process
Software Engineering Challenges
Professional Responsibilities of Software Engineers
9/19/2018
Kal Toth, Oregon State University, Software Engineering

2. Software-Intensive Systems
Large Numbers (100s, 1000s, millions) of:
Users
Developers
Lines of code
Pages of User Documentation and help screens
Pages of Requirements and Design Documentation
Customers: Governments, Businesses, Individuals
9/19/2018
Kal Toth, Oregon State University, Software Engineering

3. Software-Intensive Systems
Implementation involves distributed objects, database systems, web servers. Portable across multiple platforms.
Requirements and specifications obtained through extensive interviews, prototypes, and participant research.
Detailed test plan with automated testing.
Project requires 1-2 years.
System will evolve for 20 years after initial installation.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

4. FAQs about software engineering
What is software?
What is software engineering?
What is the difference between software engineering and computer science?
What is the difference between software engineering and system engineering?
What is a software process?
What is a software process model?
9/19/2018
Kal Toth, Oregon State University, Software Engineering

5. FAQs about software engineering
What are the costs of software engineering?
What is CASE (Computer-Aided Software Engineering)
What are the attributes of good software?
What are the key challenges facing software engineering?
9/19/2018
Kal Toth, Oregon State University, Software Engineering

6. Kal Toth, Oregon State University, Software Engineering
What is software?
Computer programs and associated documentation, installation and un-installation scripts, etc.
Software products may be
Generic - developed to be sold to a range of different customers
Custom - developed for a single customer according to their specification
9/19/2018
Kal Toth, Oregon State University, Software Engineering

7. What is software engineering?
A set of methods for the cost-efficient development and evolution of software systems.
Issues, techniques, and lessons learned from previous software projects.
Methods for acquiring and debugging requirements.
Methods for refining and debugging specifications.
Representations and languages for communicating with other software engineers.
Methods for project management (costing and scheduling).
A typical software engineer will only work on about 20 projects in his/her career. That doesn’t provide much opportunity to learn from experience. Need to study the experiences of other software engineers.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

8. Kal Toth, Oregon State University, Software Engineering
What is the difference between software engineering and computer science?
Software engineering requires skills and knowledge from computer science, but also from management, speech communications, and writing.
Computer science is concerned with the development of theory and technology.
Software engineers apply this technology, but sometimes they stumble upon new problems that have not yet been formally studied by computer scientists.
Real-world software projects are an important source of new problems for computer science.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

9. Kal Toth, Oregon State University, Software Engineering
What is the difference between software engineering and 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
System engineers are involved in system specification, architectural design, integration and deployment
9/19/2018
Kal Toth, Oregon State University, Software Engineering

10. What is a software process?
A set of activities whose goal is the development or evolution of software
Generic activities in all software processes are:
Specification - what the system should do and its development constraints
Development - production of the software system
Validation - checking that the software is what the customer wants
Evolution - changing the software in response to changing demands
9/19/2018
Kal Toth, Oregon State University, Software Engineering

11. What is a software process model?
A simplified representation of a software process, presented from a specific perspective
Examples of process perspectives are
Workflow perspective - sequence of activities
Data-flow perspective - information flow
Role/action perspective - who does what
Generic process models
Waterfall
Evolutionary development
Formal transformation
Integration from reusable components
9/19/2018
Kal Toth, Oregon State University, Software Engineering

12. Kal Toth, Oregon State University, Software Engineering
What are the costs?
Replace this with details from the text.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

13. Kal Toth, Oregon State University, Software Engineering
Development Costs
9/19/2018
Kal Toth, Oregon State University, Software Engineering

14. Kal Toth, Oregon State University, Software Engineering
Lessons
Most important goal: Reduce testing and evolution costs
Get the requirements right!
Coding is a small part of the software development cost.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

15. Computer-Aided Software Engineering?
Software systems which are intended to provide automated support for software process activities. CASE systems are often used for method support
Upper-CASE
Tools to support the early process activities of requirements and design
Lower-CASE
Tools to support later activities such as programming, debugging and testing
9/19/2018
Kal Toth, Oregon State University, Software Engineering

16. Attributes of good software?
Deliver the required functionality and performance to the user.
Maintainability
Software must evolve to meet changing needs
Dependability
Software must be trustworthy
Efficiency
Software should not make wasteful use of system resources
Usability
Software must be usable by the users for which it was designed
9/19/2018
Kal Toth, Oregon State University, Software Engineering

17. What are the key challenges facing software engineering?
Coping with legacy systems, coping with increasing diversity, and coping with demands for reduced delivery times
Legacy systems
Old, valuable systems must be maintained and updated
Heterogeneity
Systems are distributed and include a mix of hardware and software
Delivery
There is increasing pressure for faster delivery of software
9/19/2018
Kal Toth, Oregon State University, Software Engineering

18. Professional and ethical responsibility
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 behavior is more than simply upholding the law.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

19. 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 beyond their competence.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

20. 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).
9/19/2018
Kal Toth, Oregon State University, Software Engineering

21. 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 behavior 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.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

22. Code of ethics - 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.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

23. Code of ethics - principles
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.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

24. Code of ethics - principles
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.
9/19/2018
Kal Toth, Oregon State University, Software Engineering

25. Kal Toth, Oregon State University, Software Engineering
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 systems that have clear potential for harm as well as good (e.g., unbreakable encryption, eavesdropping and profiling tools, weapons systems)
9/19/2018
Kal Toth, Oregon State University, Software Engineering

26. Kal Toth, Oregon State University, Software Engineering
Conclusion
Systems engineering is hard! There will never be an easy answer to the problems of complex system development
Software engineers do not have all the answers but may be better at taking a systems viewpoint
Disciplines need to recognize each others strengths and actively rather than reluctantly cooperate in the systems engineering process
9/19/2018
Kal Toth, Oregon State University, Software Engineering