Matt Dillon writes:
>
> :What happens on an ECC equipped PC when you have a multi-bit memory
> :error that hardware scrubbing can't fix? Will there be some sort of
> :NMI or something that will panic the box?
> :
> :I'm used to alphas (where you'll get a fatal machine check panic) and
> :I am just wondering if PCs are as safe.
> :
> :Thanks,
> :
> :Drew
>
> ECC can typically detect and correct single bit errors and detect
> double bit errors. Anything beyond that is problematic... it may or
> may not detect the problem or may mis-correct a multi-bit error.
> An NMI is generated if an uncorrectable error is detected.
>
> On PC's, ECC is optional. Desktops typically do not ship with ECC
> memory. Branded servers typically do. A year or two ago I would
> have been happy to use non-ECC rams (finding bad RAM through trial
> and error), but now with capacities as they are and memory prices down
> ECC is definitely the way to go.
My sentiments exactly.
> Bit errors can come from many sources, memory being only one. Bit errors
> can occur inside the cpu chip, in the L1 and L2 caches, in memory, in
> controller chips... all over the place. Many modern processors implement
> parity on their caches to try to cover the problem areas. I'm not sure
> how Pentium III's and IV's are setup.
>
> -Matt
Hmm.. Well, it turns out that the box I"m insterested in (Thunder K7)
can be set to send an SERR on multiple bit errors. I wonder what
happens when a pc gets an SERR? (that's another machine check
on alpha)
Drew
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