From owner-freebsd-hackers@FreeBSD.ORG Sat Jul 10 13:47:49 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 0C8D216A4CE for ; Sat, 10 Jul 2004 13:47:49 +0000 (GMT) Received: from woozle.rinet.ru (woozle.rinet.ru [195.54.192.68]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5EE1343D1F for ; Sat, 10 Jul 2004 13:47:48 +0000 (GMT) (envelope-from marck@rinet.ru) Received: from localhost (localhost [127.0.0.1]) by woozle.rinet.ru (8.12.11/8.12.11) with ESMTP id i6ADlk5J042672; Sat, 10 Jul 2004 17:47:46 +0400 (MSD) (envelope-from marck@rinet.ru) Date: Sat, 10 Jul 2004 17:47:46 +0400 (MSD) From: Dmitry Morozovsky To: Jean-Sebastien Roy In-Reply-To: <40EF172C.7020508@jeannot.org> Message-ID: <20040710174546.T85065@woozle.rinet.ru> References: <40EF172C.7020508@jeannot.org> X-NCC-RegID: ru.rinet MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: freebsd-hackers@freebsd.org Subject: Re: 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: Sat, 10 Jul 2004 13:47:49 -0000 Hi there, On Sat, 10 Jul 2004, Jean-Sebastien Roy wrote: JR> I'm currently using FreeBSD 4.10 on an HP D530 SFF. JR> The system is perfectly stable except for the following problem JR> I'm unable to understand : JR> JR> When I mount a cdrom (mount /cdrom), then calculate the MD5 hash JR> of a big file on a CD (md5 /cdrom/bigfile), the results are often random: JR> unmounting, mounting again and calculating again the MD5 often result in JR> a different value. What disturb me the most is that absolutely no errors JR> are reported in any log (no read errors for example). JR> JR> I thought the CDROM reader, a LITE-ON LTR-48327S PQS3, was the culprit, JR> so I replaced it with a PLEXTOR DVDR PX-712A and got the exact same JR> results (i.e. random MD5 values). I checked the RAM using memtest and JR> got no errors. The problem does not occur for files on the harddisk. JR> JR> hw.ata.atapi_dma is set since both drives support it and it seems to be JR> required for proper CD/DVD burning. The CD drive is the master on its JR> own ATA bus. JR> JR> While the problem occurs on multiple CDs (mostly RW), to my surprise, I JR> was not able to reproduce the problem by reading big files on DVDs. JR> JR> Could someone provide me a hint on what to check next or how to fix this JR> problem ? Can errors on CDs generate such a behavior ? What if you copy that big file from CD to HD twice (possibly with unmounting/remounting in the middle) and check MD5s there? Testing your memory with memtest86.com's test would also be helpful to eliminate RAM issues. Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------