From owner-freebsd-questions@FreeBSD.ORG Fri Jul 9 20:43:43 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2E5F816A4CE for ; Fri, 9 Jul 2004 20:43:43 +0000 (GMT) Received: from internet.potentialtech.com (h-66-167-251-6.phlapafg.covad.net [66.167.251.6]) by mx1.FreeBSD.org (Postfix) with ESMTP id 083A943D3F for ; Fri, 9 Jul 2004 20:43:43 +0000 (GMT) (envelope-from wmoran@potentialtech.com) Received: from working.potentialtech.com (pa-plum-cmts1e-68-68-113-64.pittpa.adelphia.net [68.68.113.64]) by internet.potentialtech.com (Postfix) with ESMTP id 529D369A39; Fri, 9 Jul 2004 16:43:42 -0400 (EDT) Date: Fri, 9 Jul 2004 16:43:41 -0400 From: Bill Moran To: Jean-Sebastien Roy Message-Id: <20040709164341.6b0d4523.wmoran@potentialtech.com> In-Reply-To: <40EEC01F.8030405@jeannot.org> References: <40EEC01F.8030405@jeannot.org> Organization: Potential Technologies X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; i386-portbld-freebsd4.9) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit cc: freebsd-questions@freebsd.org Subject: Re: Silent errors when reading CDs X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Jul 2004 20:43:43 -0000 Jean-Sebastien Roy wrote: > Hi ! > > I'm currently using FreeBSD 4.10 on an HP D530 SFF. > The system is perfectly stable except for the following problem > I'm unable to understand : > > When I mount a cdrom (mount /cdrom), then calculate the MD5 hash > of a big file on a CD (md5 /cdrom/bigfile), the results are often random: > unmounting, mounting again and calculating again the MD5 often result in > a different value. What disturb me the most is that absolutely no errors > are reported in any log (no read errors for example). > > I thought the CDROM reader, a LITE-ON LTR-48327S PQS3, was the culprit, > so I replaced it with a PLEXTOR DVDR PX-712A and got the exact same results > (i.e. random MD5 values). I checked the RAM using memtest and got no > errors. The problem does not occur for files on the harddisk. > > hw.ata.atapi_dma is set since both drives support it and it seems to be > required for proper CD/DVD burning. The CD drive is the master on its > own ATA bus. > > Could someone provide me a hint on what to check next or how to fix this > problem ? > > Thank you very much in advance, I tried this out on my machine, which is completely different hardware/config than yours, and I could not reproduce the problem. It would seem to me that the problem is either hardware-specific or the result of the above-mentioned sysctl (my atapi_dma is turned off, and I'm too lazy to reboot to try it on) This question may be better suited for hackers@ -- Bill Moran Potential Technologies http://www.potentialtech.com