From owner-freebsd-hackers@FreeBSD.ORG Fri Jul 9 22:07:43 2004 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0AE8E16A4CF for ; Fri, 9 Jul 2004 22:07:43 +0000 (GMT) Received: from durandal.jeannot.org (durandal.jeannot.org [80.65.225.54]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3536443D5E for ; Fri, 9 Jul 2004 22:07:42 +0000 (GMT) (envelope-from js@jeannot.org) Received: from [127.0.0.1] (localhost [127.0.0.1])i69M7eBf001841 for ; Sat, 10 Jul 2004 00:07:41 +0200 (CEST) (envelope-from js@jeannot.org) Message-ID: <40EF172C.7020508@jeannot.org> Date: Sat, 10 Jul 2004 00:07:40 +0200 From: Jean-Sebastien Roy User-Agent: Mozilla Thunderbird 0.7.1 (X11/20040703) X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Mailman-Approved-At: Sat, 10 Jul 2004 11:57:34 +0000 Subject: Silent errors when reading CDs X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Jul 2004 22:07:43 -0000 Hi ! (Following an advice from someone at freebsd-questions@, this is a repost of a question asked at freebsd-questions@) 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. While the problem occurs on multiple CDs (mostly RW), to my surprise, I was not able to reproduce the problem by reading big files on DVDs. Could someone provide me a hint on what to check next or how to fix this problem ? Can errors on CDs generate such a behavior ? Thank you very much in advance, Regards, Jean-Sebastien