From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from blood.actrix.co.nz ([203.96.16.163]) by canuck.infradead.org with esmtp (Exim 4.52 #1 (Red Hat Linux)) id 1EHWuw-00016j-1h for linux-mtd@lists.infradead.org; Mon, 19 Sep 2005 21:27:50 -0400 From: Charles Manning To: linux-mtd@lists.infradead.org Date: Tue, 20 Sep 2005 13:32:31 +1200 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200509201332.31431.manningc2@actrix.gen.nz> Cc: Gagan Prakash Subject: Re: FAT on raw Nand List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tuesday 20 September 2005 10:36, Gagan Prakash wrote: > Hi > > I am trying to solve the problem of allowing a device with raw nand to be > exposed to any Desktop OS (OS 10, Windows and Linux) without having to > install any sort of driver on the Desktop OS that is not already present. > The only solution I have read of/come up with is for the device to act as > USB external drive and let the host OS mount it as a FAT filesystem. This > means that the filesystem on device partition that is exposed needs to be > FAT. If you can't install any drivers then FAT is probably the only way to go for a FS. The only alternative I can think of to this is to use ethernet + nfs instead. ie. Your device looks like a USB ethernet device with a host running nfs on the other end. That would allow you to run an alternative FS like YAFFS. > > Now from the archives I know its not the easiest and safest thing to > expose a partition as FAT on raw nand. And it also requires the writing of > a FTL layer. I was wondering if there is a better solution for this > problem. > > For example is there a way to emulate FAT on top of existing nand fs like > YAFFS or JFFS2 (this would seem hard specially for writes). Or is the only > solution is to format the device as FAT and expose it as an external USB > drive to the host OS. Unfortunately there is no USB-NFS. There is only a USB mass storage device which can be used with most block file systems (typically FAT). USB-NFS would have been a good idea because it would allow devices to use their own FS internally. The USB Mass Storage spec has no notion of a file system, just read/write blocks of data. To use YAFFS etc on the device and make it look like a USB mass storage device running FAT is probably too much to ask.