By: dmcq (dmcq.delete@this.fano.co.uk), September 21, 2022 4:10 am
Room: Moderated Discussions
hobold (hobold.delete@this.vectorizer.org) on September 20, 2022 6:38 am wrote:
> Michael S (already5chosen.delete@this.yahoo.com) on September 19, 2022 8:47 am wrote:
> [...]
> > Without internal knowledge I fully expect that either classic Hamming codes or something
> > very similar is used in practice for L2 cache ECC and also, on devices that have it, for L1D ECC.
>
> Hamming distances sounds about right. What I was trying to add to the discussion
> is analogous to homomorphic encryption: the possibility to do correct computation
> on encoded data without decoding it first and re-encoding it afterwards.
>
> In the case of encryption this is usually inefficient (because the payload data has to remain verifiably secret
> the whole time). But for ECC purposes there might be codes that allow for efficient partial update
Well one can always exclusive or the bits corresponding to bits that hav changed in ECC - I doubt that's worth the bother though.
> Michael S (already5chosen.delete@this.yahoo.com) on September 19, 2022 8:47 am wrote:
> [...]
> > Without internal knowledge I fully expect that either classic Hamming codes or something
> > very similar is used in practice for L2 cache ECC and also, on devices that have it, for L1D ECC.
>
> Hamming distances sounds about right. What I was trying to add to the discussion
> is analogous to homomorphic encryption: the possibility to do correct computation
> on encoded data without decoding it first and re-encoding it afterwards.
>
> In the case of encryption this is usually inefficient (because the payload data has to remain verifiably secret
> the whole time). But for ECC purposes there might be codes that allow for efficient partial update
Well one can always exclusive or the bits corresponding to bits that hav changed in ECC - I doubt that's worth the bother though.