From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wproxy.gmail.com ([64.233.184.194]) by canuck.infradead.org with esmtp (Exim 4.43 #1 (Red Hat Linux)) id 1CrLmZ-0005O2-06 for linux-mtd@lists.infradead.org; Wed, 19 Jan 2005 14:46:24 -0500 Received: by wproxy.gmail.com with SMTP id 36so37077wra for ; Wed, 19 Jan 2005 11:46:16 -0800 (PST) Message-ID: <6934efce05011911462552f555@mail.gmail.com> Date: Wed, 19 Jan 2005 11:46:16 -0800 From: Jared Hulbert To: "Artem B. Bityuckiy" In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit References: <1105619501.26551.163.camel@hades.cambridge.redhat.com> <6934efce05011810013ea479b@mail.gmail.com> Cc: David Woodhouse , MTD List Subject: Re: CRC on Read-Only partition Reply-To: Jared Hulbert List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > The question is: if we've read page and encounter ECC error, is it > possible that if we re-read it several times we will have no errors? This > means does NAND technology assume random occasional bit flips which go > away after we re-read page? Whether or not the error goes away was not the point. My point is that with NAND you can get errors even with RO data. That's all. > P.S. : > Toshiba's guide stands bit flipping is possible, but they stay until block > is erased. Re-read as many times as yiu want - you will still have this > bit error. But this doesn't mean block is bad - erase the block and be > happy. I think the real question is whether the likelyhood of errors getting past the NAND's ECC is > or < than the users tolerance level. I don't believe that the answer should be terribly different for RO or RW data. Yet this depends on temperature, frequency of read, and yes even solar flares :) Therefore the answer is different for a set top box with an expected useful life of 2 years and a car.