From owner-freebsd-hackers@freebsd.org Wed Sep 16 12:04:28 2015 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 414069CE340; Wed, 16 Sep 2015 12:04:28 +0000 (UTC) (envelope-from rb@gid.co.uk) Received: from mx0.gid.co.uk (mx0.gid.co.uk [194.32.164.250]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id DCF2E1B6D; Wed, 16 Sep 2015 12:04:27 +0000 (UTC) (envelope-from rb@gid.co.uk) Received: from [194.32.164.24] (80-46-130-69.static.dsl.as9105.com [80.46.130.69]) by mx0.gid.co.uk (8.14.2/8.14.2) with ESMTP id t8GC4PLp018426; Wed, 16 Sep 2015 13:04:25 +0100 (BST) (envelope-from rb@gid.co.uk) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Subject: Re: ECC support From: Bob Bishop In-Reply-To: Date: Wed, 16 Sep 2015 13:04:20 +0100 Cc: Konstantin Belousov , Hackers freeBSD , Dieter BSD , Andriy Gapon , freebsd-hardware@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: <93106DFF-9741-4515-B6E0-AC43C0AF2179@gid.co.uk> References: <55F88A18.6090504@FreeBSD.org> <20150916035904.GE67105@kib.kiev.ua> <93871ADA-EDA3-481C-9959-1D371AB44479@gid.co.uk> <3678FC1E-DDC5-4FB2-B6E9-6FC90D0C988E@gid.co.uk> To: Igor Mozolevsky X-Mailer: Apple Mail (2.2104) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Sep 2015 12:04:28 -0000 > On 16 Sep 2015, at 12:52, Igor Mozolevsky = wrote: >=20 > On 16 September 2015 at 12:34, Bob Bishop wrote: >=20 > >=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