1. Reliability and Safety
What can go wrong?

2. Risks of Computing They support many aspects of our security:
Fly by wire aircraft
Patient monitoring and care administration
Financial transactions
Telephone networks
Military surveillance and responses

3. Three Categories of Failures
Problems for individuals
System failures that affect large numbers of people or cost large amounts of money
Problems in safety-critical applications

4. Problems for Individuals
Billing Errors
Not enough care - input error
Not enough testing - reasonable range
Not enough training

5. Database Accuracy Problems
Info in database is not accurate
Automatic entering of info - mistakes can be overlooked
Erroneous duplication - copies of incorrect info can be in other systems
Insufficient training - not knowledgeable enough about the system

6. Possible States of a Computer
Functioning correctly
Functioning incorrectly
Down
Intentionally off

7. Causes of Computer Failure
Faulty design of software or hardware
Sloppy implementation
Careless or insufficiently trained users
Poor user interfaces
Hardware/Software malfunctions
Specification errors
Scope/Application inconsistency

8. Computer Users Perspective
Should user should understand…
limitations of the computers
the need for proper training
the need for responsible use
the difference between good products and bad ones

9. Computer Professional Perspective
The professional should…
study computer failures
study computer ethics

10. Educated Member of Society Perspective
Education will…
help us evaluate the reliability and safety of various computer applications
help evaluate computer technology

11. Relevant Research Topics
Architecture: hardware and software
Systems engineering
Reasoning; languages, techniques and engineering
Requirements analysis
Fault tolerance
Repair and maintenance
Holistic safety arguments
Formal methods
Real-time issues

12. Consumer Hardware and Software
Usually have more serious errors in their first releases
Regularly sold with known bugs
Hardware also has flaws
Tradeoff between cost, debugging, and marketing
Dishonesty, denials of problems, lack of adequate response to complaints