One of my profs at Carnegie Mellon relayed a story from the space shuttle program (well, several stories, but this one is germane) — all systems on board had to be heavily redundant, so they installed four identical copies of the control software.
Of course, when the first one fails and rolls over to the second identical copy, what do you expect it’s going to do with the same bad data? And the third, and the fourth?
An unrelated story had do do with the mechanical folks trying to figure out how much the software weighed...
LOL! That's just awesome.
That one smells like an urban legend to me!