1. OHJELMISTOJEN TOTEUTUS - SOFTWARE ENGINEERING
Today - motivation: - Software Engineering: Why? - Software Engineering: What?

2. WHY SOFTWARE ENGINEERING?
High failure rate of software projects.
Also the partially succesfull software projects have problems.
A belief that systematic work could improve things.

3. HOW TO IDENTIFY SOFTWARE PROJECT SUCCESS
The product is accepted or sells
Economical profit
Low error rate
Schedule and budget are kept

4. SUCCESS FACTORS Good project management
Understanding the needs and freezing the requirements
Controlled implementation and delivery
Skilled project personnel
Sufficient resources
Good communication between groups

5. MAJOR ERRORS Too optimistic design Over-emphasizing technology
Management problems
No profitability pre-evaluation
Unrealistic resources
Communication problems

6. SUCCESS STUDIES - ONNI’88 (Finland)
Over 100 projects
Good success: 33%
Questionable: 42%
Failure: 25%

7. ONNI’88 - REASONS FOR FAILURE
Inabilities of the Software Engineering personnel
Insufficient resources
Management problems

8. SUCCESS STUDIES: USA’82 - Gibson & Singer
18 projects
Good success: 17%
Partly usable/in use: 28%
Satisfactory (just about?) 11%
Failure: 22%
No evaluation: 11%

9. USA’82 - REASONS FOR FAILURE
Organisational problems
New work methods and salary policies
Unexpected changes in business

10. FORSMAN’S STUDIES (FINLAND)
From Forsman’s book ”ATK-projektin läpivienti”, Suomen ATK-kustannus Oy, 1995
17 projects
Good success: 18%
Partially usable/in use: 29%
Satisfactory (just about?): 29%
Failure: 24%

11. FORSMAN - REASONS FOR FAILURE
Problems in organisation and attitudes
The customer could not decide what it wants
Problems with customer and software producer communication
Inexperience of the software producer

12. EXAMPLES OF FAILING SOFTWARE RISKS:
Nuclear war
General technical device malfunction (e.g. failing life-support devices)
Economical transaction failures
Economical losses in business
Personal tragedies from faulty information
Y2K - ?

13. A BELIEF IN SYSTEMATIC WORK AND METHODS
There is no way to guarantee success
Sometimes also the not so good practices seem to bring some success
However, the studies suggest that the way software is made is meaningful for the success, at least statistically
Practical observations support the belief

14. LARGE SYSTEMS
Some problems grow with the size of the software, below we give example sizes:
Dutch KLM airline reservation system (1993), assembler loc (lines of code)
Unix System V, relese 4.0 with Xnews and X11, over loc
Nokia NMS/2000 network management system, over loc
NASA Space Shuttle software, lines of object code
IBM OS360: 5000 man years of development

15. SOFTWARE ENGINEERING - WHAT
IEEE: Software engineering is the systematic approach to the development, operation, maintenance, and retirement of software
An earlier definition: Software engineering is the establishment and use of sound engineering principles in order to obtain economically software that is reliable and works efficiently on real machines.

16. SOFTWARE ENGINEERING - WHAT (observations)
Software engineering concerns the construction of large programs.
Mastering complexity is essential.
Regular co-operation between people is an integral part of the process.
Software evolves.
Software development efficiency is important
The software has to serve its purpose and users.