1. Objectives of the Lecture
To introduce software engineering and to explain its importance in dealing with large software systems.
To provide answers to key questions about software design and development as part of software engineering discipline.

2. Software systems
The impact of software systems on modern society and technology for 50 years.
Process automation: automobile industry; refinery; software product family for electronic devices; telephony and switching systems
Equipment control: embedded systems in different electronic devices such as home appliances; automobile control gadgets
Scientific problems: differential equations; matrix operations; model checking; searching algorithms; information system manipulation
Entertainment industry: gaming; graphics; movies; music
Education and office management: distance education; word processors; databases; spreadsheets; slide presenters
Software systems are around for more than 50 years. They are implemented to assist human in different aspects of their lives such as: process……

3. Software systems … Example of very large software systems
Flight simulators; medical and imaging applications; air-traffic control; banking; telecommunications; etc.
These systems are written in more than 500 different languages.
Billions of lines of source code are written for mission critical software systems worldwide.
process automation: automobile industry; product families; refineries; ..
Equipment control: embedded systems in different electronic devices

4. Software engineering to solve software crisis
Software crisis refers to the current state of software technology in dealing with development and maintenance of large and complex software systems. Instances are:
For every 8 large projects, 2 are cancelled.
Most projects exceed their time-schedule by 50%.
75% of large software systems malfunction after completion.
Detecting and correcting errors take 50% of time and effort.
Maintenance cost of a system is 60% of entire cost.
An example: baggage-handling system at Denver international airport
4000 telecars, 5000 electric-eyes, 400 radio receivers, 100 computers, cost $193 million
Discuss the cause of each instance of software crisis:
Project management
Project management and lack of understanding of the problem
Lack of accurate software specification
Errors that are left in the system since the development was not standard and precise
Errors that remained in the system from beginning that is requirement specification SRS
The grand opening of the airport was delayed for 9 months because the baggage conveyer belt did not work properly, and had high speed at in the curves that caused the luggage's to be thrown out of the conveyer belt. It cost one-million dollar per day for the airport because of delay in operation.
Software engineering tackles the software crisis by providing disciplined processes and methodologies to design, implement, and maintain large systems.

5. Software engineering key questions
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?

6. Software engineering…
What are the costs of software engineering?
What are software engineering methods?
What is CASE (Computer-Aided Software Engineering)
What are the attributes of good software?
What are the key challenges facing software engineering?

7. What is software? Computer programs and associated documentation:
SRS, SDS, Technical manual, User manual, Source code, Binary files, Build files, Versions
Tool provided documents: Reverse Engineering aspects, Tracing code to requirement
Software products may be
Generic - developed to be sold to a range of different customers
Customized - developed for a single customer according to their specification

8. What is software engineering?
“Multi-person construction of multi-version software” [Parnas 1978]
Software engineering is an engineering discipline which is concerned with all aspects of software production
Software engineers should adopt a systematic and organised approach to their work and use appropriate tools and techniques depending on the problem to be solved, the development constraints and the resources available

9. Professional Responsibilities of Software Engineers
Accept individual responsibility
Solve the real problem
Be honest about capabilities and competence
Produce reviewable designs
Consider maintainability of product
Respect to confidentiality of the clients
Knowledge of IP rights for patents, copyright, etc.
No computer miss-use by e.g., computer games; spreading computer viruses
P.Eng. Applicants write Ethics and Law Exams

10. What is the difference between software engineering and computer science?
Computer science is concerned with theory and fundamentals; software engineering is concerned with the practicalities of developing and delivering useful software
Computer science theories are currently insufficient to act as a complete underpinning for software engineering
Computer science:
* Theory: design of algorithms, complexity of the computations; computational geometry;
* System: databases, distributed systems; web technology;
* Scientific computation; computer graphics;
* Software Engineering deals with the appropriate methodologies, techniques, and tools to design or analysis of large software systems. : reverse engineering; forward engineering; formal methods and tools

11. 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

12. 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

13. 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

14. What are the costs of software engineering?
Roughly 60% of costs are development costs, 40% are testing costs. For custom software, evolution costs often exceed development costs
Costs vary depending on the type of system being developed and the requirements of system attributes such as performance and system reliability
Distribution of costs depends on the development model that is used

15. What are software engineering methods?
Structured approaches to software development which include system models, notations, rules, design advice and process guidance
Model descriptions
Descriptions of graphical models which should be produced
Rules
Constraints applied to system models
Recommendations
Advice on good design practice
Process guidance
What activities to follow

16. What is CASE (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

17. What are the attributes of good software?
The software should deliver the required functionality and performance to the user and should be maintainable, dependable and usable
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

18. 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