From owner-freebsd-fs@FreeBSD.ORG Tue Jun 20 15:51:06 2006 Return-Path: X-Original-To: freebsd-fs@freebsd.org Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DE68216A47B for ; Tue, 20 Jun 2006 15:51:06 +0000 (UTC) (envelope-from matt@genesi-usa.com) Received: from mail.genesippc.com (mithrandir.softwarenexus.net [66.98.186.96]) by mx1.FreeBSD.org (Postfix) with ESMTP id 326B843D45 for ; Tue, 20 Jun 2006 15:51:06 +0000 (GMT) (envelope-from matt@genesi-usa.com) Received: from p54b0ffec.dip.t-dialin.net ([84.176.255.236] helo=yukito) by mail.genesippc.com with esmtpa (Exim 4.62 (FreeBSD)) (envelope-from ) id 1FsiRl-00026Y-7Y; Tue, 20 Jun 2006 15:47:21 +0000 From: "Matt Sealey" To: "'Simon Truss'" , Date: Tue, 20 Jun 2006 10:51:00 -0500 Organization: Genesi Message-ID: <00bf01c69481$57a793d0$99dfdfdf@bakuhatsu.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 Thread-Index: AcaUf7hGXMcuzdaZSAa9DGmhTv2gtwAAMh4w In-Reply-To: <449817BE.50104@bigblue.demon.co.uk> Cc: Subject: RE: On-disk format of UFS/UFS2 (for firmware implementation) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: matt@genesi-usa.com List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Jun 2006 15:51:07 -0000 > You probably are looking for this paper: > > A Fast File System for UNIX (1984) > http://citeseer.ist.psu.edu/12920.html We have this implemented already in the firmware. However this does not help reading UFS2 (64-bit numbers, extents etc. and myriad other things to look out for). > Sleuthkit contains code to read many file systems and its > code may assist in extracting the design of FFS. > http://www.sleuthkit.org/ > > There has been work on flash file systems for BSD, a quick > search may turn up something useful. Why a flash filesystem? Our OpenFirmware has disk support, it pushes them into the device tree and you can load/boot any file on any supported filesystem (this includes IDE, SCSI, USB disks..) We just want to parse and use UFS filesystems, i.e. the modern ones that OpenBSD (UFS) and FreeBSD and NetBSD (UFS2) use. FFS isn't the same thing, as I am told by hundreds of articles... at least there are some differences which I have found hard to find the documentation on. In theory we should be able to implement the entire gamut in one filesystem support package, the same way the Linux ufs driver does, by adapting the "1984 FFS" driver. For that we need to know what we are doing.. :) The Sleuthkit guy seems to have written a book which may be very useful to us (if we order it..) http://www.digital-evidence.org/fsfa/ and this is more like what we are looking for. Source code as documentation is really the last resort when it comes to supporting things as it makes for very hard and expensive work. -- Matt Sealey Manager, Genesi, Developer Relations