Re:ECC matters
by EvanAnderson on Sunday January 03, 2021 @02:55PM
(#25624629)
The Space Shuttle had redundant computers. The Apollo Guidance Computer was not redundant (though there were two AGCs onboard-- one in the CM and one in the LEM). The aerospace industry has a history of using redundant dissimilar computers (different CPU architectures, multiple implementations of the control software developed by separate teams in different languages, etc) in voting-based architectures to hedge against various failure modes.
Re:ECC matters
by buildbuildbuild on Sunday January 03, 2021 @03:03PM
(#25624725)
This remains common in aerospace, each voting computer is referred to as a "string". https://space.stackexchange.com/questions/45076/what-is-a-fl...
In aerospace where this is common, you often had multiple implementations, as you wanted to avoid software bugs made by humans. Problem was, different teams often created the same error at the same place, so it wasn’t as effective as it would have seemed.
Forgive my ignorance, but wouldn't the computer actually reacting to the calculation (and sending a command or displaying the data) still be very vulnerable to bit-flips? Or were they displaying the results from multiple machines to humans?
The Apollo missions (or was it the Space Shuttle?) did this. They had redundant computers that would work with each other to determine the “true” answer.