Modern Software Problems - The Technical and Social History of Software Engineering - page 371

This is a cautionary tale about how software bugs can potentially damage na-
tional and global economies. The problem was almost immediately recognized as
a software bug, but in an industry where millions of dollars of stocks change hands
every minute, it took more than 30 minutes to stop programmed trading with the
software. Apparently, the problem was in a new update installed on the day of the
problem, clearly without adequate testing or validation.
Rogue trading software or major bugs in trading software has the theoretical
potential of damaging the entire world's financial systems. Knight Capital's own
stock declined by about 77% due to this software problem. There may also be fu-
ture litigation from stock purchasers or companies who feel that they were dam-
aged by the event. The SEC called for a meeting to examine the problem.
Lessons learned: The major lesson from the Knight Capital software bug is that
financial software in the United States needs much stronger governance than it
gets today. Financial applications should have, but do not have, the same kinds
of certification that is required of medical applications by the FDA and avion-
ics applications by the FAA. In these fields, bugs or errors can cause enormous
and totally unpredictable damages. In the case of medical and avionics software,
deaths can occur. In the case of financial software, national or even global mal-
functions of the economy might occur.
Problem avoidance: In thinking about the Knight Capital software problems,
formal inspections and requirements modeling are the two methods with the
highest probability of finding the problems. Static analysis would probably have
missed it since the issue was a logical omission rather than a syntactic problem.
Pair programming might not have worked because the problem seems to have ori-
ginated upstream in requirements and design.
Deeper analysis is needed to find out why testing did not identify the problem,
but the obvious reasons are casual test-case design, lack of risk-based testing, and
probably testing by amateurs instead of certified test personnel.
2012: Automotive Safety Recalls Due to Software
The original intent of this discussion was to show the specific software recalls for
a single automobile line such as Toyota. However, the web has so many stories of
software recalls involving so many automobiles that it is becoming an automot-
ive industry scandal. Software now controls fuel injection, brakes, automobile en-
gines, navigation packages, and other systems. Any or all of these software-con-
trolled features can malfunction.