Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757511AbXFKTpr (ORCPT ); Mon, 11 Jun 2007 15:45:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753519AbXFKTpg (ORCPT ); Mon, 11 Jun 2007 15:45:36 -0400 Received: from bill.weihenstephan.org ([82.135.35.21]:40697 "EHLO bill.weihenstephan.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756928AbXFKTpf (ORCPT ); Mon, 11 Jun 2007 15:45:35 -0400 X-Greylist: delayed 1064 seconds by postgrey-1.27 at vger.kernel.org; Mon, 11 Jun 2007 15:45:34 EDT From: Juergen Beisert Organization: Privat To: DervishD , Linux-kernel Subject: Re: ext2 on flash memory Date: Mon, 11 Jun 2007 21:27:41 +0200 User-Agent: KMail/1.9.4 References: <20070611101319.GA14284@DervishD> <20070611174223.GB2433@DervishD> In-Reply-To: <20070611174223.GB2433@DervishD> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706112127.42119.juergen127@kreuzholzen.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1668 Lines: 34 On Monday 11 June 2007 19:42, DervishD wrote: > I just was curious about the issue and I was asking to know if > anybody had tried this. Think about compact flash devices. They also using some kind of flash memory and also doing wear leveling. And I think they are not only used with FAT16/32! If they run with different filesystems, then your pendrive stick will also. Only the interface is different. > I know about cheap pendrives that you cannot format even with FAT32, only > with FAT16. I'm not sure if the price was the reason that they failed with different filesystems. Some kind of wear leveling tries to guess which blocks of the filesystem are in use and which are unused (to avoid wear leveling of unused data). But it only works if you are using a filesystem that is "known" by the wear leveling process. If you are using a different one, it fails badly, because it tries to interpret a FAT that does not exists, and destroys your filesystem while the wear leveling process is running. So this cheap pendrive was too intelligent for filesystems other than FAT16.... So if you can use a different filesystem than FAT16/32 on your pendrive, it does not matter what kind of filesystem you are using. The wear leveling process has no clue about it and always "wear leveling" used *and* unused data (means: every block of the whole disk) until it ruins the flash memory. Hope it helps Juergen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/