Date: Sun, 3 Mar 2013 14:56:42 -0800 (PST) From: Andrew Pack <andrewpack54@yahoo.com> To: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: VIA PV530 Message-ID: <1362351402.61999.YahooMailNeo@web164001.mail.gq1.yahoo.com>
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Does anyone have any experience running FreeBSD on this platform? Unless I'= m mistaken, I could't find it listed under the new release compatibility li= st.=A0 From owner-freebsd-questions@FreeBSD.ORG Mon Mar 4 00:36:06 2013 Return-Path: <owner-freebsd-questions@FreeBSD.ORG> Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 29370233 for <freebsd-questions@freebsd.org>; Mon, 4 Mar 2013 00:36:06 +0000 (UTC) (envelope-from freebsd@edvax.de) Received: from mx01.qsc.de (mx01.qsc.de [213.148.129.14]) by mx1.freebsd.org (Postfix) with ESMTP id CB4F7E4 for <freebsd-questions@freebsd.org>; Mon, 4 Mar 2013 00:36:05 +0000 (UTC) Received: from r56.edvax.de (port-92-195-109-47.dynamic.qsc.de [92.195.109.47]) by mx01.qsc.de (Postfix) with ESMTP id D7F233CDE4 for <freebsd-questions@freebsd.org>; Mon, 4 Mar 2013 01:36:03 +0100 (CET) Received: from r56.edvax.de (localhost [127.0.0.1]) by r56.edvax.de (8.14.5/8.14.5) with SMTP id r240a8jP076942 for <freebsd-questions@freebsd.org>; Mon, 4 Mar 2013 01:36:08 +0100 (CET) (envelope-from freebsd@edvax.de) Date: Mon, 4 Mar 2013 01:36:08 +0100 From: Polytropon <freebsd@edvax.de> To: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Grepping though a disk Message-Id: <20130304013608.7981e8a9.freebsd@edvax.de> Organization: EDVAX X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; i386-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: Polytropon <freebsd@edvax.de> List-Id: User questions <freebsd-questions.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>; List-Post: <mailto:freebsd-questions@freebsd.org> List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, <mailto:freebsd-questions-request@freebsd.org?subject=subscribe> X-List-Received-Date: Mon, 04 Mar 2013 00:36:06 -0000 Due to a fsck file system repair I lost the content of a file I consider important, but it hasn't been backed up yet. The file name is still present, but no blocks are associated (file size is zero). I hope the data blocks (which are now probably marked "unused") are still intact, so I thought I'd search for them because I can remember specific text that should have been in that file. As I don't need any fancy stuff like a progress bar, I decided to write a simple command, and I quickly got something up and running which I _assume_ will do what I need. This is the command I've been running interactively in bash: $ N=0; while true; do echo "${N}"; dd if=/dev/ad6 of=/dev/stdout bs=10240 count=1 skip=${N} 2>/dev/null | grep "<PATTERN>"; if [ $? -eq 0 ]; then break; fi; N=`expr ${N} + 1`; done To make it look a bit better and illustrate the simple logic behind my idea: N=0 while true; do echo "${N}" dd if=/dev/ad6 of=/dev/stdout bs=10240 count=1 skip=${N} \ 2>/dev/null | grep "<PATTERN>" if [ $? -eq 0 ]; then break fi N=`expr ${N} + 1` done Here <PATTERN> refers to the text. It's only a small, but very distinctive portion. I'm searching in blocks of 10 kB so it's easier to continue in case something has been found. I plan to output the resulting "block" (it's not a real disk block, I know, it's simply a unit of 10 kB disk space) and maybe the previous and next one (in case the file, the _real_ block containing the data, has been split across more than one of those units. I will then clean the "garbage" (maybe from other files) because I can easily determine the beginning and the end of the file. Needless to say, it's a _text_ file. I understand that grep operates on text files, but it will also happily return 0 if the text to search for will appear in a binary file, and possibly return the whole file as a search result (in case there are no newlines in it). My questions: 1. Is this the proper way of stupidly searching a disk? 2. Is the block size (bs= parameter to dd) good, or should I use a different value for better performance? 3. Is there a program known that already implements the functionality I need in terms of data recovery? Results so far: The disk in question is a 1 TB SATA disk. The command has been running for more than 12 hours now and returned one false-positive result, so basically it seems to work, but maybe I can do better? I can always continue search by adding 1 to ${N}, set it as start value, and re-run the command. Any suggestion is welcome! -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
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