CSCI 310 Midterm Questions With Complete Solutions

Software Engineering Failures correct answer: Ariane 5 Rocket - overflow caused rocket to explode Mars Climate Orbitor - did not use metric units so orbitor crashed Therac 25 - gave 100x radiation due to lack of testing and user interface World War III - soviet early warning system registered sun off of clouds as nukes Hartford Coliseum Collapse - wet snow caused roof to collapse since there was an error in domain knowledge by the cad software Patriot Fails - gulf war missle interception system had a rounding error that caused the missiles to be too slow and a barracks blew up Disastrous Study - The New England Journal of Medicine reported increased suicide rates after severe natural disasters but were false since error doubled the suicides for one year y2k - computer systems only used 2 numbers for date which would cause issues in 2000 cost billions - did not test with lots of users so only 1% of people could sign up Challenges in Software Design correct answer: Scale: Larger = harder Complexity: lots of APIs, web services Uniqueness: no software is the same Culture: requires a lot of planing of complex systems and maitnence Speed: software expected to be faster which is hard Legacy software: understanding and using past software Changeability software must be flexible Systematic correct answer: done according to