From ben@somanetworks.com Fri May 29 00:56:57 2009 Received: from ns1.somanetworks.com ([216.126.67.39] helo=zimbra.somanetworks.com) by stoneboat.aleph1.co.uk with esmtp (Exim 4.69) (envelope-from ) id 1M9pSw-0001ko-TG for yaffs@lists.aleph1.co.uk; Fri, 29 May 2009 00:56:57 +0100 Received: from localhost (localhost [127.0.0.1]) by zimbra.somanetworks.com (Postfix) with ESMTP id A48A06B0004; Thu, 28 May 2009 19:56:52 -0400 (EDT) X-Virus-Scanned: amavisd-new at zimbra.somanetworks.com Received: from zimbra.somanetworks.com ([127.0.0.1]) by localhost (zimbra.somanetworks.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IJiX8ArE4-JT; Thu, 28 May 2009 19:56:52 -0400 (EDT) Received: from benjamin-gamsas-macbook.local (69-196-152-236.dsl.teksavvy.com [69.196.152.236]) by zimbra.somanetworks.com (Postfix) with ESMTP id 4A3556B0001; Thu, 28 May 2009 19:56:52 -0400 (EDT) Message-ID: <4A1F24C4.8050300@somanetworks.com> Date: Thu, 28 May 2009 19:56:52 -0400 From: Benjamin Gamsa User-Agent: Thunderbird 2.0.0.21 (Macintosh/20090302) MIME-Version: 1.0 To: Charles Manning References: <4A1EBBD1.4090803@somanetworks.com> <200905290938.56581.manningc2@actrix.gen.nz> <4A1F0EE7.8050509@somanetworks.com> <200905291051.39134.manningc2@actrix.gen.nz> In-Reply-To: <200905291051.39134.manningc2@actrix.gen.nz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 216.126.67.39 X-SA-Exim-Mail-From: ben@somanetworks.com X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on stoneboat.aleph1.co.uk X-Spam-Level: X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00 autolearn=no version=3.2.5 X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:14:11 +0000) X-SA-Exim-Scanned: Yes (on stoneboat.aleph1.co.uk) Cc: yaffs@lists.aleph1.co.uk Subject: Re: [Yaffs] failed erases causing block retirement X-BeenThere: yaffs@lists.aleph1.co.uk X-Mailman-Version: 2.1.11 Precedence: list List-Id: Discussion of YAFFS NAND flash filesystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 May 2009 23:56:57 -0000 Charles Manning wrote: > On Friday 29 May 2009 10:23:35 Ben Gamsa wrote: >> Charles Manning wrote: >>> It is safe to retry erases from a yaffs perspective, but if blocks are >>> really failing erases (ie. not just a driver issue) I would be a bit >>> concerned as to their health and would not want to reuse those blocks. >> Right, that was my concern too. I guess what I wasn't sure of is >> whether an erase failure is almost always (barring driver issues) an >> indication of a bad block, or whether, like writes, it can be a >> temporary glitch for which retries make sense. Since in my case it >> turned out to be a driver issue, I still don't know the answer to this >> question, but it is now less pressing. > > It very much depends on flash technology, but if you're getting write and > erase errors I'd say you're typically playing with fire to keep using them. > Since yaffs retries on writes, I presume in the case of writes there is good reason to believe that a block that fails to write once but succeeds a second time is safe to keep using. ben