CptS 401 Adam Carter

Announcement  Executive decision: no class Thursday! (CH and exam review will take place tomorrow instead)  Be sure that you submit a digital copy of your final submissions! Failure to do so may result in a reduced grade

Quiz Question The cause of computer system failures can be attributed to A. Faulty design B. Slow computers C. A & B D. None of the above 3

Answer  A “…faulty design, sloppy implementation, careless or insufficiently trained users, and poor interfaces” (405) 4

Quiz Question The following is not a factor that contributes to the problems that computer databases cause for people: A. A large population B. Automated processing without human intervention C. Inaccurate biometric data D. Errors in data entry E. Lack of accountability for errors 5

Answer: C Several Factors Contribute to Database Problems  A large population (many with similar names)  Automated processing can’t always recognize special cases or doesn’t use common sense  Overconfidence in accuracy of data  Human errors in data entry  Data are not updated or maintained  Humans aren’t accountable for problems (blame it on computer!) 6

Quiz Question In the context of Ch. 8, RSI stands for A. Redundant System Inputs B. Recalibrated System Integrity C. Repetitive Safety Isometrics D. Redundant Safety Information E. None of the above 7

Answer: RSI = Repetitive Strain Injuries (E) (see gray box on p. 411)  Have you experienced pain from using a keyboard or mobile device for extended periods of time? A: Yes B: No 8

Quiz Question A strategy mentioned by the book for making electronic voting machines less vulnerable to fraud and sabotage is A. requiring the machines to be housed in a locked cabinet B. requiring the software they use to be public C. keeping the software they use secret D. All of the above E. None of the above 9

Answer  B (416)  Is having open-source software on voting machines a good idea? 10

Quiz Question The book discusses the failures of complex computer systems at three different airports. What was a common reason all three failed? A. They had not undergone sufficient testing B. They were unable to handle incorrect user input C. They were too complex to work properly D. None of the above 11

Answer  A (419)  The book implies that all three systems were rushed.  Do any of our students from Hong Kong remember the airport incident there? 12

Quiz Question  In the past 10 years, the number of fatal accidents in relation to total flights A. Has gone up B. Has gone down C. Has stayed the same

Answer  B (424)

Discussion  Has anyone in this class been the victim of computer error?

Class Discussion  Do software errors worry you?

Discussion  So far, the Daemon’s plans have executed perfectly. Given what we know about software failure, does this seem likely?

Discussion  The book provides several examples of people placing complete trust on computer results. Is this a positive (good) trend? A. Yes B. No

Discussion  The book mentions that at the time of the writing (2008), 30,000 people have been falsely identified as terrorists. More than likely, this number has gone up.  Given that there are probably significantly less than 30,000 terrorists in the world, do our precautions work?

Discussion  Y2K : Real or hype?