Re: File browser
Gordon Beaton wrote:
On Fri, 08 Feb 2008 09:57:33 +0100, Philipp wrote:
Daniel Pitts wrote:
Case and point, there was once an automated medical scanning device that
worked 99.9% of the time, but there were a few accidents that no one
could figure out what happened. A few patients died from over-exposure
to radiation. This product of course had been extensively tested and
retested, and worked for so much of the time, but due to a race
condition it could fail (catastrophically) in an unexpected way.
I'd be interested in a reference for that. Can you remember where you
read it?
http://en.wikipedia.org/wiki/Therac-25 summarizes and has links to
further reading, all of it interesting.
Actually the manufacturer *claimed* that it had been extensively
tested, but that wasn't really the case.
The original article describing the details of the case was published in the
IEEE publication /Computer/ in the early 90s, IIRC. (The article is
referenced from the Wikipedia link.) It was written in a dry, dispassionate
and objective style that made the account all the more chilling for its
refusal to sensationalize.
The manufacturer didn't start claiming that it fixed the problem until enough
people found out that there was a problem; originally they suppressed the
information. Once they were called to account, they were fond of rapidly
responding with bizarre claims like "reliability has been improved 5000%".
Aside from the meaninglessness of such statements absent any baseline
measurement of "reliability", it is clear the manufacturer actually did
nothing to solve the problem except try to hide it and let people die.
--
Lew