Trust, Safety & Reliability INTRODUCTION TO COMPUTER ERRORS TEXTBOOK: BRINKMAN’S ETHICS IN A COMPUTING CULTURE READING: CHAPTER 5, PAGES ,

Computer errors A range of possible consequences – Seconds lost, other inconvenience – Data lost – $ - $$$ – Injuries and deaths Examples: – Disfranchised voters – False arrests – Price & billing errors – Air traffic control, airplane control

The Apocalypses That Might Have Been

Apocolypse cont’d

Hardware Errors Failure of the physical components of the computer system

Software Errors o “Bugs” o Bug v. mistake debate ◦Ariane 5 ◦ariane 5 explosion – YouTubeariane 5 explosion – YouTube ◦Floating point number storage ◦Arithmetic overflow

Computer Solves the Wrong Problem Complexity of programming: garbage in, garbage out Gemini 5, 105 miles off landing target: Earth’s rotation is not 360° in 24 hr but ° Friendship 7, 40 miles off landing target: Failure to take into account weight loss in aircraft due to use of consumables

Misuse The Hernandez situation: ◦Roberto Hernandez was pulled over running a stop sign ◦When the officer ran his license the officer was convinced that he was dealing with a wanted man, Roberto Hernandez Same birthday, similar height, weight, tattoo. Officer was convinced that the name difference was a mistake in the system. It was not.

Communication Failure Misunderstandings ◦Of what the system is capable of or how it works ◦See example of airliner running out of fuel ◦

Special Topic: Electronic Voting Electronic voting machines: ◦After the "hanging chad" controversy of the 2000 election, Congress passed a federal law that gave states funding to replace their punch card and lever voting systems with electronic voting machines

Implementation of electronic voting North Carolina 2004 ◦Voting machine manufacturer said the electronic voting machine could handle 10,500 votes each ◦Reality – could only hold 3,005 votes ◦Result – lost 4,530 votes Many voting machines do not create a paper trail ◦Voting machines used by as many as a quarter of American voters in 2012 can be hacked with just $26 in parts and an 8th grade science education ◦Vulnerability Assessment Team at Argonne National Laboratory ◦The experts say the hack could change voting results while leaving absolutely no trace of the manipulation behind

System testing ◦Flaws in modeling real events ◦Verification: does the computer program correctly implement program? ◦Not understanding all relevant issues ◦Validation: does the model accurately represent the real system?