Software Errors Who is to blame?

Almost everything in our daily lives is controlled by CPU’s and software… Does Embedded Software = Embedded Disasters? 3 concerns: Reliability Safety Security

You might choose to believe that once software runs correctly, it will run correctly forever. However, a series of tragedies and chaos caused by software proves this is wrong

Therac-25 alerts us that it is dangerous to surrender completely to a software-controlled mechanism (1986) The British destroyer Sheffield was sunk because the radar system identified an incoming missile as “friendly.” (1982)

Mars Climate Orbiter (1999) ◦Was designed to land on Mars, but was destroyed as it attempted to land. NASA believed is entered the atmosphere at a higher speed than intended. ◦Some of the software developers used metric units (newtons), others used pounds. ◦Simple miscommunication led to lose of the $327 million probe.

Software can have small, unnoticeable errors that can culminate in disaster In 1991, during the Gulf War an missile defense system’s clock error missed /second in precision in every.1 of a second, accumulating for 100 hours. This made a Patriot missile fail to intercept a scud missile. The Scud struck an American Army barracks and killed 28 soldiers. After 100 hours of operation there was an error of at least 0.34 seconds, which translates to over 544 meters (1/3 of a mile) of error in prediction of the missile’s location.

Having the embedded software in your washing machine or ATM issue incorrect commands may not seem very serious; But, in airplanes, heart pace-makers, or radiation therapy machines, a software error can easily claim people’s lives.

Apple Maps directions send drivers to Alaska airport — via the main runway Fairbanks airport officials barricaded access road after iPhones gave Apple Maps directions that sent drivers across the runway. Two vehicles in the past three weeks have turned onto airport property and pulled up to the terminal on the passenger jet side. (2013)

Let’s begin with the Therac-25…