Subject: Re: memory error
To: Rui Paulo <rpaulo@netbsd-pt.org>
From: Michael <macallan18@earthlink.net>
List: port-sparc
Date: 06/09/2005 07:25:36
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Hello,

> > It would be good if NetBSD could use, store, and maintain a "bad page=20
> > map" so that once a bad page in RAM is identified (through parity/ECC=20
> > errors), it can be avoided.
>=20
> Hmm, if a parity error happens, does it mean it's going to happen again a=
nd
> again ?

Most likely. And if ECC can't cover it up you'll get all kinds of nastiness=
 from it.=20

> How can we be sure that reading/writing again to the same RAM location
> will yield the same error ?

We can't. If it's just one bit that's stuck you won't even get a parity err=
or every time you access it ( because it would be in the right position hal=
f the time )

But adding code that checks for a stuck bit in the NMI handler and then dis=
ables the page ( or puts it on a bad list or whatever ) wouldn't be too har=
d I guess.

have fun
Michael

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