From owner-freebsd-small@FreeBSD.ORG Thu May 18 02:25:27 2006 Return-Path: X-Original-To: freebsd-small@freebsd.org Delivered-To: freebsd-small@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 203EA16A739 for ; Thu, 18 May 2006 02:25:27 +0000 (UTC) (envelope-from mf.danger@gmail.com) Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.185]) by mx1.FreeBSD.org (Postfix) with ESMTP id E8A1143D45 for ; Thu, 18 May 2006 02:25:25 +0000 (GMT) (envelope-from mf.danger@gmail.com) Received: by nf-out-0910.google.com with SMTP id x29so23412nfb for ; Wed, 17 May 2006 19:25:24 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=UUsCXAlffb/rC9DeI87nmqiIaoVJvWbCB9HyuqbTaHyZ4+ZFDyeqWa1lWQfWRVX2GkfK/MClj8y0E54juz0xrHaTYX1bG/1ofzcKljuibNqDHmJ+YsZUZKJZX+RFsm1xfUbqW4MvCCJd8SPfiJBQ1KR7W3WokXQncmAg6nfW1DY= Received: by 10.48.48.19 with SMTP id v19mr1245155nfv; Wed, 17 May 2006 17:46:16 -0700 (PDT) Received: by 10.49.55.14 with HTTP; Wed, 17 May 2006 17:46:16 -0700 (PDT) Message-ID: <9f7850090605171746p5ff4dbefq46211ce93aafc116@mail.gmail.com> Date: Wed, 17 May 2006 17:46:16 -0700 From: "marty fouts" To: "Benno Rice" In-Reply-To: <446BBE65.50104@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <446BBE65.50104@FreeBSD.org> Cc: gnn@freebsd.org, freebsd-small@freebsd.org Subject: Re: Flash File Systems or Translation Layers? X-BeenThere: freebsd-small@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Dedicated and Embedded Systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 May 2006 02:25:27 -0000 On 5/17/06, Benno Rice wrote: > gnn@freebsd.org wrote: > > Howdy, > > > > So, a few of us have talked off list of the need for a flash file > > system or translation layer for FreeBSD in order to better target the > > kind of boards we want to support. The one lead I had was to a poorly > > written, binary only solution with nasty licensing. That is, it was > > a dead end. Does anyone know of anything that exists now that we > > might coopt or have the knowledge to do this right/well? > > I thought about doing a port of jffs2. Probably a rewrite actually, so > we can have a non-GPL version. It's waiting on me getting to the point > where I need it though. =3D) > You probably don't want jffs2, because it has, um, interesting, performance characteristics. I also vaguely recall reading that the authors had stopped development on jffs3. Also, jffs requires MTD, and it's debatable whether a rewrite of MTD would be a good thing or not. See discussions on the yaffs mailing list and, IIRC, one of the NetBSD mailing lists on this recently. It's not clear to me that "flash" is a good dividing point for making a file system. It seems a lot more likely that NOR and NAND flash are enough different that they would require their own file systems, or, at the least, their own address translation layers. Marty