From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31219 invoked by alias); 12 Oct 2009 01:13:12 -0000 Received: (qmail 31210 invoked by uid 22791); 12 Oct 2009 01:13:11 -0000 X-SWARE-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from virtual.bogons.net (HELO virtual.bogons.net) (193.178.223.136) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 12 Oct 2009 01:13:04 +0000 Received: from jifvik.dyndns.org (jifvik.dyndns.org [85.158.45.40]) by virtual.bogons.net (8.10.2+Sun/8.11.2) with ESMTP id n9C1D0428581; Mon, 12 Oct 2009 02:13:01 +0100 (BST) Received: from [172.31.1.126] (neelix.jifvik.org [172.31.1.126]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by jifvik.dyndns.org (Postfix) with ESMTP id 883B53FEB; Mon, 12 Oct 2009 02:13:00 +0100 (BST) Message-ID: <4AD2829B.3050807@jifvik.org> Date: Mon, 12 Oct 2009 01:13:00 -0000 From: Jonathan Larmour User-Agent: Mozilla Thunderbird 1.0.8-1.1.fc4 (X11/20060501) MIME-Version: 1.0 To: =?ISO-8859-1?Q?J=FCrgen_Lambrecht?= Cc: eCos developers Subject: Re: NAND technical review References: <4ACB4B58.2040804@ecoscentric.com> <4ACD9FC3.1030508@televic.com> In-Reply-To: <4ACD9FC3.1030508@televic.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Mailing-List: contact ecos-devel-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: ecos-devel-owner@ecos.sourceware.org X-SW-Source: 2009-10/txt/msg00011.txt.bz2 Jürgen Lambrecht wrote: > Ross Younger wrote: >> Now, I mentioned ECC data. NAND technology has a number of underlying >> limitations, importantly that it has reliability issues. I don't have >> a full >> picture - the manufacturers seem to be understandably coy - but my >> understanding is that on each page, a driver ought to be able to cope >> with a >> single bit having flipped either on programming or on reading. The >> > > Such a "broken bit" is because the transistor that contains the bit is > physically broken, and is stuck at 1 or at 0 (I don't know if it can be > both). So you cannot anymore erase it (flip it back to 1) or program it > (flip to 0). > > I thought only programming or erasing could break it, not reading? > Is somebody sure about this? I've had experience of dodgy flash that spontaneously started getting bit errors either over time or on reads - couldn't tell which. Really it was NOR, rather than NAND, but that should be /more/ reliable! I think it's probably best to assume that if it's hardware, it can go wrong :-). [ NB I'll be replying to other mails in this thread tomorrow, but it's a bit late here at the moment for me to start ] Jifl -- --["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine