From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ig0-x229.google.com ([2607:f8b0:4001:c05::229]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xx8zY-0000CR-B7 for linux-mtd@lists.infradead.org; Sat, 06 Dec 2014 06:37:20 +0000 Received: by mail-ig0-f169.google.com with SMTP id hl2so1886769igb.2 for ; Fri, 05 Dec 2014 22:36:58 -0800 (PST) Received: from [172.16.10.16] (66-162-60-14.static.twtelecom.net. [66.162.60.14]) by mx.google.com with ESMTPSA id uf2sm404183igc.11.2014.12.05.22.36.56 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Dec 2014 22:36:57 -0800 (PST) Message-ID: <5482A407.4070002@gmail.com> Date: Sat, 06 Dec 2014 01:36:55 -0500 From: Peter Barada MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: Re: What does oob stand for in mtd.h? References: <54827EEB.7030305@gmail.com> In-Reply-To: <54827EEB.7030305@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 12/05/2014 10:58 PM, nick wrote: > Greetings MTD subsystem developers, > I am wondering what oob stands for in mtd.h as a lot of functions are using it in their names. This would greatly need in me understanding the core of this subsystem if something points out what this stands for. > "Google is your friend". :) A search for "NAND oob" turns up multiple URLs that can shed light on the meaning of OOB in the context of a NAND device. But to suffice, OOB = "Out Of Band" meaning the bytes of "extra" sotrage read/written with every page access of a NAND device (aka the "spare area" of each page). Usually the OOB area contains ECC bytes (to correct the NAND in the case of a bit flip during read), and probably metadata (used by YAFFS and other NAND-based filesystems). -- Peter Barada peter.barada@gmail.com