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Date:      Wed, 16 Sep 2015 13:04:20 +0100
From:      Bob Bishop <rb@gid.co.uk>
To:        Igor Mozolevsky <igor@hybrid-lab.co.uk>
Cc:        Konstantin Belousov <kostikbel@gmail.com>, Hackers freeBSD <freebsd-hackers@freebsd.org>, Dieter BSD <dieterbsd@gmail.com>, Andriy Gapon <avg@freebsd.org>, freebsd-hardware@freebsd.org
Subject:   Re: ECC support
Message-ID:  <93106DFF-9741-4515-B6E0-AC43C0AF2179@gid.co.uk>
In-Reply-To: <CADWvR2ha0-ifBYTswdVF7tzZsHayf%2BKXVdk86S0tuuPmLKj6cg@mail.gmail.com>
References:  <CAA3ZYrBXZn1WpHWYGJYWJDPsk7iDahCas8RhnHC4w%2Babf4w4hA@mail.gmail.com> <55F88A18.6090504@FreeBSD.org> <20150916035904.GE67105@kib.kiev.ua> <93871ADA-EDA3-481C-9959-1D371AB44479@gid.co.uk> <CADWvR2gBDjKFRW-X6ECJaGG7tSvOgk0rTk38O1qQ0hUWjRBF_A@mail.gmail.com> <3678FC1E-DDC5-4FB2-B6E9-6FC90D0C988E@gid.co.uk> <CADWvR2ha0-ifBYTswdVF7tzZsHayf%2BKXVdk86S0tuuPmLKj6cg@mail.gmail.com>

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> On 16 Sep 2015, at 12:52, Igor Mozolevsky <igor@hybrid-lab.co.uk> =
wrote:
>=20
> On 16 September 2015 at 12:34, Bob Bishop <rb@gid.co.uk> wrote:
>=20
> <snip>
>=20
>=20
>> "The best we can conclude therefore is that any chip size effect is
>> unlikely to dominate error rates given that the trends are not =
consistent
>> across various other confounders such as age and manufacturer.=E2=80=9D=

>>=20
>> I=E2=80=99ll admit to talking that point up a bit but it is =
counterintuitive.
>> Memory designers have always been scared of cosmic rays etc but the
>> suspected effects simply have not been noticeable. Most likely as =
they
>> shrink features ever smaller, other factors like material purity =
dominate.
>>=20
>=20
> I saw that after I posted, and had a long ponder as to why it would be =
so.
> The only thing I could think of is that the fab process was(/is?) =
large
> enough to not worry about "nonsense" like cosmic rays &c (but then =
I've not
> had much exposure to semi-conductor electronics theory since late =
90s).
> Perhaps we're at a point where the fab process can't really shrink =
much
> more with DRAM due to the underlying tech (effectively many tiny RC
> circuits), which is the reason the manufacturers just stack ranks to =
get
> more capacity per DIMM instead of packing more in a single chip?..

Dunno. I=E2=80=99ll ask my tame semiconductor expert when I see him =
tomorrow...

> --=20
> Igor M.
> _______________________________________________
> freebsd-hardware@freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-hardware
> To unsubscribe, send any mail to =
"freebsd-hardware-unsubscribe@freebsd.org"

--
Bob Bishop
rb@gid.co.uk







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