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Then you're replicating and not error correcting. I've not seen any replication systems that use the replicas to detect errors. Even RAID 1 which is a pure mirroring solution only fetches one of the copies when reading & will ignore corruption on one of the disks unless you initiate a manual verification. There are technical reasons why that is related to read amplification as well as what it does to your storage cost.

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cortesoft 3 days ago | parent [-]

I guess that is true, pure replication would not allow you to correct errors, only detect them.

However, I think explaining the concept as duplicating some data isn’t horrible wrong for non technical people. It is close enough to allow the person to understand the concept.

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vlovich123 3 days ago | parent [-]

To be clear. A hypothetical replication system with 3 copies could be used to correct errors using majority voting.

However, there's no replication system I've ever seen (memory, local storage, or distributed storage) that detects or corrects for errors using replication because of the read amplification problem.

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bawolff 3 days ago | parent [-]

https://en.wikipedia.org/wiki/Triple_modular_redundancy

	▲	vlovich123 2 days ago \| parent [-]
		The ECC memory page has the same non sensical statement: > Error-correcting memory controllers traditionally use Hamming codes, although some use triple modular redundancy (TMR). The latter is preferred because its hardware is faster than that of Hamming error correction scheme.[16] Space satellite systems often use TMR,[17][18][19] although satellite RAM usually uses Hamming error correction.[20] So it makes it seem like TMR is used for memory only to then back off and say it’s not used for it. ECC RAM does not use TMR and I suggest that the Wikipedia page is wrong and confused about this. The cited links on both pages are either dead or are completely unrelated, discussing TMR within the context of fpgas being sent into space. And yes, TMR is a fault tolerance strategy for logic gates and compute more generally. It is not a strategy that has been employed for storage full stop and evidence to the contrary is going to require something stronger than confusing wording on Wikipedia.