PPRuNe Forums - View Single Post - Why so many computers for flight controls in A320?
Old 28th Jun 2013, 17:24
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DozyWannabe
 
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Originally Posted by IFLY_INDIGO
Another point I would like to add is that redundancy means duplication which usually 'kicks in' AFTER a failure.

Sharing processing job among many computer is not redundancy. it is reducing risk of failure by not letting a single computer run the entire show.
Not always true. Even simple redundant systems such as multiple elevator (as in lift) cables can have all of them sharing a load at any given time, it's just that losing one or more of them will allow the system to continue functioning enough to ensure a safe outcome. Likewise, the cross-checking that goes on between the ADIRU modules has all of them working on similar data, monitoring for discrepancies.

Such functions in the computing world are a specialised form of redundancy known as "Defence In Depth".

http://en.wikipedia.org/wiki/Defense...pth_(computing)

Last edited by DozyWannabe; 28th Jun 2013 at 17:31.
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