From owner-freebsd-arch@FreeBSD.ORG Tue Apr 1 04:55:21 2008 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8E7AF10656CD; Tue, 1 Apr 2008 04:55:21 +0000 (UTC) (envelope-from mfouts@danger.com) Received: from mx.danger.com (wall.danger.com [216.220.212.140]) by mx1.freebsd.org (Postfix) with ESMTP id 7617F8FC30; Tue, 1 Apr 2008 04:55:21 +0000 (UTC) (envelope-from mfouts@danger.com) Received: from danger.com (exchange3.danger.com [10.0.1.7]) by mx.danger.com (Postfix) with ESMTP id 6F771409D23; Mon, 31 Mar 2008 21:55:07 -0700 (PDT) X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Date: Mon, 31 Mar 2008 21:55:15 -0700 Message-ID: In-Reply-To: <20080331223846.CFD975BAE@mail.bitblocks.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Flash disks and FFS layout heuristics Thread-Index: AciTf/3rlDZiIGCpSl2L4XsPLGVpdwANHLxA References: Your message of "Mon, 31 Mar 2008 22:23:37 -0000." <26080.1207002217@critter.freebsd.dk> <20080331223846.CFD975BAE@mail.bitblocks.com> From: "Martin Fouts" To: "Bakul Shah" , "Poul-Henning Kamp" Cc: Christopher Arnold , arch@freebsd.org, qpadla@gmail.com, freebsd-arch@freebsd.org Subject: RE: Flash disks and FFS layout heuristics X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Apr 2008 04:55:21 -0000 =20 > -----Original Message----- > From: Bakul Shah [mailto:bakul@bitblocks.com]=20 > Sent: Monday, March 31, 2008 3:39 PM > To: Poul-Henning Kamp > Cc: Matthew Dillon; Christopher Arnold; arch@freebsd.org;=20 > qpadla@gmail.com; freebsd-arch@freebsd.org; Martin Fouts > Subject: Re: Flash disks and FFS layout heuristics=20 > One thing I forgot to add: I'd let the lower level handle bad=20 > block forwarding and wear levelling (like on the m-tron device). >=20 One of the difficulties of doing things this way comes from the complexity of dealing with garbage collection when you want to reuse an erase unit.