“I am not in the office at the moment. Send any work to be translated.”

WinVote Security One of several systems built in response to Help America Vote Act of 2002 Based on Windows XP Uses Wi-Fi to program election details and download results In 2014 reports of crashing when a poll worker downloaded music on his iPhone Led to new assessment of the system

WinVote Security Results XP embedded not patched since 2004 Uses WEP, considered obsolete in 2004 due to security flaws WEP key hardwired to “abcde” Disabling Wi-Fi disabled the WinVote app, left XP exposed Windows administrator password set to “admin” with no interface to change it No logs or checksums to detect tampering with system’s database “If system was not hacked it was only because nobody tried”

In other cases it is not so funny.

Patriot Timing Glitch Loses Scud 25 Feb 1991 (Gulf War) Iraqi scud rocket hits American base in Saudia, killing 28 Patriot missile battery failed to track the scud Patriot keeps time using 0.1 sec clock Calculates seconds by multiplying by 1/10 Using 24-bit value for 1/10 lost 0.34 sec after 100 hours of operation Scud travels >500m in this time, and tracking failed

AA 965 Crash – 159 Dead 20 Dec 1995 flight from Miami to Colombia Pilots entered “R” for Rozo waypoint into navigational computer “R” also represented Romeo waypoint, which was somewhere else Romeo was more common, so it was the default Plane automatically turned towards Romeo Unfortunately there was a mountain in the way

Ariane 5 Explodes 4 Jun 1996, maiden flight of new launcher for placing satellites into orbit Destroyed after ~40 seconds due to obvious flight problems Primary cause: failure to convert a 64-bit value into 16-bits in inertial reference system (SRI) Secondary cause: diagnostic error data from SRI was interpreted as (extremely strange) flight data by main computer Trying to “correct” flight led to instability

Ariane 5 Irony The original 64-bit value is used only for alignment before launch, but left on for ~45 sec later as was desired in Ariane 4 Backup SRI ran identical software, had same failure – Assumes that errors are random and shutdown is a good solution Conversion was not checked because in Ariane 4 values were indeed much smaller

NASA Loses Mars Climate Orbiter Orbiter Launched in 1998, reached Mars in 1999 Supposed to orbit at km, but went as low as 57km, causing excessive stress and friction Cause: computer controlling the thrusters underestimated their power by a factor of 4.45 Root cause: not converting metric units specified by NASA to Imperial units used by software

LA Air Traffic Loses Radio Contact 14 Sep 2004 afternoon Air traffic controllers lose radio contact with ~400 planes, backup fails within 1 minute System uses touch screen to create voice channels between controller and airplane or other controller Upon failure controllers couldn’t alert pilots about necessary course changes Several near collisions avoided by on-board collision avoidance systems that alerted pilots

LA Air Contact Lose Causes Technicians did not perform 30-day reboot – System looked OK Reboot regulation instated after previous failures occurred after 49.7 days Cause of failures is a 32-bit millisecond timer used for continuous self test (and other things) When counter reaches 0 system crashes

Knight Trading loses $440M 1 Aug 2012 at 9:30-10:15 AM Repeatedly trade about 140 securities, buying them at the (high) ask price and selling at the (low) bid price Repeat ~40 times per second for 45 minutes Example: in security where price difference is 15 cents/share, lose $6/sec = $360/min or $16,200 in the 45 minutes for each share This was part of testing new software